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Evaluation of<br />
Opportunities for<br />
Converting Indigenous UK<br />
Wastes <strong>to</strong> Fuels and<br />
Energy<br />
Report <strong>to</strong> <strong>the</strong> National Non-Food Crops Centre<br />
This project was managed <strong>by</strong> <strong>the</strong> NNFCC and<br />
funded Report/proposal <strong>by</strong> DECC. <strong>to</strong> (name of company)<br />
Restricted Commercial<br />
Restricted Commercial<br />
ED Numbers<br />
ED45551<br />
Issue Number<br />
Issue Number 1<br />
Date 2007<br />
July 2009
2<br />
Evaluation of Opportunities for Converting Indigenous UK Wastes <strong>to</strong> Fuels and Energy<br />
AEA/ED45551/Issue 1<br />
Title Evaluation of Opportunities for Converting Indigenous UK Wastes <strong>to</strong> Fuels<br />
and Energy<br />
Cus<strong>to</strong>mer National Non-Food Crops Centre (NNFCC)<br />
Cus<strong>to</strong>mer reference 09/012<br />
Confidentiality,<br />
copyright and<br />
reproduction<br />
Copyright AEA Technology<br />
This proposal is submitted <strong>by</strong> AEA Technology in response <strong>to</strong> an invitation<br />
<strong>to</strong> tender from <strong>the</strong> NNFCC “Review of technologies for gasification of<br />
biomass and wastes in <strong>the</strong> UK”. It may not be used for any o<strong>the</strong>r purposes,<br />
reproduced in whole or in part, nor passed <strong>to</strong> any organisation or person<br />
without <strong>the</strong> specific permission in writing of <strong>the</strong> Commercial Manager, AEA<br />
Technology plc.<br />
File reference M:\Projects\Consultancy\NNFCC\Report<br />
Reference number ED45551<br />
AEA Energy & Environment<br />
The Gemini Building<br />
Fermi Avenue<br />
Harwell International Business Centre<br />
Didcot<br />
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t: 0870 190 6036<br />
f: 0870 190 6318<br />
AEA is a business name of AEA Technology plc<br />
AEA is certificated <strong>to</strong> ISO9001 and ISO14001<br />
Author Name Louise Evans, Shoko Okamura, Jim Poll, Nick Barker<br />
Approved <strong>by</strong> Name Pat Howes<br />
Signature<br />
Date 04.09.2009
Evaluation of Opportunities for Converting Indigenous UK Wastes <strong>to</strong> Fuels and Energy<br />
AEA/ED45551/Issue 1<br />
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1 Executive Summary<br />
Main Conclusions<br />
The UK has a large resource of waste materials that could be used for renewable energy.<br />
Data on municipal solid waste composition and arisings is very good; however data for industrial and<br />
commercial arisings is poor.<br />
Processes that deliver heat, or combined heat and power with a high heat <strong>to</strong> power ratio, give excellent<br />
greenhouse gas abatement potential. To maximise <strong>the</strong> benefit installations need <strong>to</strong> be sized <strong>to</strong> match <strong>the</strong><br />
energy demand, ra<strong>the</strong>r than <strong>the</strong> <strong>to</strong>nnage of waste, resulting often in smaller installations in a multiplicity of<br />
locations. These will require <strong>the</strong> use of fuels with consistent properties such as graded wood chip, or<br />
solid recovered fuels. Processes for <strong>the</strong> production of <strong>the</strong>se fuels should be regarded as important<br />
enabling technologies. Their technical development should be supported as should <strong>the</strong>ir introduction in <strong>to</strong><br />
<strong>the</strong> market as a traded commodity such through <strong>the</strong> development of standards and codes.<br />
Anaerobic digestion for <strong>the</strong> treatment of food and o<strong>the</strong>r wet organic waste is technically viable and has<br />
substantial environmental benefits when <strong>the</strong> product gas is used <strong>to</strong> fuel combined heat and power<br />
installations or is cleaned for injection in<strong>to</strong> <strong>the</strong> natural gas distribution system. There is however a<br />
potential barrier <strong>to</strong> future progress due <strong>to</strong> <strong>the</strong> constraint on land availability for <strong>the</strong> disposal of <strong>the</strong><br />
digestate posed <strong>by</strong> its nitrogen content, in additional <strong>to</strong> its economic feasibility in a number if situations.<br />
Combustion remains <strong>the</strong> default technology for energy generation. Gasification processes are less<br />
developed but those that burn <strong>the</strong> product gas in a boiler seem <strong>to</strong> be a robust option with some<br />
advantages over conventional combustion.<br />
Considerable work is currently underway <strong>to</strong> develop and demonstrate <strong>the</strong> production of transport fuels<br />
from biomass and waste using gasification. It is likely <strong>to</strong> be several years before <strong>the</strong>se technologies<br />
make an impact on <strong>the</strong> UK market.<br />
The production of pipeline gas <strong>by</strong> gasification and methanation shows great potential but <strong>the</strong>re is little<br />
data on <strong>the</strong> benefits of <strong>the</strong> process in particular <strong>the</strong> use of <strong>the</strong> high grade heat available from <strong>the</strong><br />
methanation reac<strong>to</strong>r.<br />
The majority of <strong>the</strong>rmal gasification and pyrolysis processes require regularly sized, consistent feeds<strong>to</strong>cks<br />
underling <strong>the</strong> importance of <strong>the</strong> development of a market for traded waste fuels.<br />
NNFCC can make a very useful contribution <strong>by</strong> building on its strengths in information provision and<br />
communication with stakeholders.<br />
The NNFCC tasked AEA with delivering an Evaluation of Opportunities for Converting Indigenous UK<br />
Wastes <strong>to</strong> Fuels and Energy. Such a study requires an investigation of <strong>the</strong> UK waste arisings <strong>by</strong> type<br />
and <strong>by</strong> region, combined with an in depth consideration of <strong>the</strong> technologies available <strong>to</strong> convert such<br />
wastes and how <strong>the</strong>ir adoption might best be encouraged.<br />
This study is an important element in developing <strong>the</strong> NNFCC’s position with regard <strong>to</strong> waste utilisation<br />
options. The findings will enable <strong>the</strong> NNFCC <strong>to</strong> develop an appropriate and effective insight in<strong>to</strong> <strong>the</strong><br />
waste situation and market in <strong>the</strong> UK, and how it might be used as a resource <strong>to</strong> derive energy and fuels.
Evaluation of Opportunities for Converting Indigenous UK Wastes <strong>to</strong> Fuels and Energy<br />
AEA/ED45551/Issue 1<br />
The NNFCC’s current focus is materials and energy from crops, and as a proportion of <strong>the</strong> UK’s waste<br />
arisings originate from agricultural activities, <strong>the</strong> opportunity <strong>the</strong>refore exists <strong>to</strong> develop a strong and<br />
coherent position on <strong>the</strong> utilisation of <strong>the</strong>se wastes <strong>to</strong> generate energy and fuels.<br />
To fulfil <strong>the</strong> objectives of <strong>the</strong> task set for this study we <strong>the</strong>refore need <strong>to</strong> understand a number of aspects<br />
of <strong>the</strong> current and future waste industry. The most important are<br />
• <strong>the</strong> character and extent of <strong>the</strong> waste resource,<br />
• <strong>the</strong> status of those energy technologies with improved resource efficiency, and,<br />
• <strong>the</strong> benefits that <strong>the</strong>ir adoption might bring.<br />
• Following <strong>the</strong> review of technologies we considered what role NNFCC might have in realising<br />
<strong>the</strong> benefits.<br />
1.1 The character and extent of <strong>the</strong> waste resource<br />
In this study <strong>the</strong> wastes that have been identified as having <strong>the</strong> potential for conversion <strong>to</strong> fuels and<br />
energy have been subdivided as follows:<br />
• Municipal solid wastes (MSW)<br />
• Commercial and industrial wastes (C&I)<br />
• Construction and Demolition (C&D)<br />
• Bio-Solids (Sewage Sludge)<br />
• Agricultural<br />
o Wet residues<br />
o Dry residues<br />
• Forestry Residues<br />
The <strong>to</strong>tal UK waste arisings of all types were estimated <strong>to</strong> be 335 million <strong>to</strong>nnes in 2004 and 307 million<br />
<strong>to</strong>nnes in 2005. This includes nearly 100 million <strong>to</strong>nnes of minerals waste from mining and quarrying, and<br />
220 million <strong>to</strong>nnes of controlled wastes from households, commerce and industry. Household wastes<br />
represent about 9 per cent of <strong>to</strong>tal arisings.<br />
His<strong>to</strong>rically, waste arisings have been shown <strong>to</strong> grow in line with, or even above, <strong>the</strong> level of economic<br />
growth. However, <strong>the</strong> continuation of this trend is now considered <strong>to</strong> be unsustainable, and thus <strong>the</strong> sixth<br />
Environment Action Programme 1 set an objective <strong>to</strong> achieve a decoupling of resource use from economic<br />
growth through significantly improved resource efficiency, dematerialisation of <strong>the</strong> economy and waste<br />
prevention.<br />
The premise of this study is that much of <strong>the</strong> waste that is currently disposed of through conventional<br />
incineration or <strong>to</strong> landfill could be used more efficiently as a feeds<strong>to</strong>ck for more efficient generation of<br />
heat and power, pipeline gas, or <strong>the</strong> production of transport fuels.<br />
To investigate this we first consider each waste resource from <strong>the</strong> viewpoint of its origin <strong>the</strong>n from <strong>the</strong><br />
perspective of its content of material that could be used for fuels.<br />
Municipal Solid Waste comprises a very large range of materials, and <strong>to</strong>tal waste arisings are<br />
increasing. Recycling initiatives decrease <strong>the</strong> proportion of waste going straight for disposal, and <strong>the</strong><br />
level of recycling is increasing each year. Most growth forecasts use a growth rate of 0.75% per annum.<br />
Commercial and Industrial waste is also comprised of a very large range of materials. Overall levels of<br />
industrial waste are decreasing, while levels of commercial wastes are increasing. Again, recycling<br />
initiatives decrease <strong>the</strong> proportion of waste going straight for disposal, and <strong>the</strong> level of recycling is<br />
increasing each year. Growth rates have been taken as 1% per annum for commercial waste, and 0%<br />
per annum for industrial waste.<br />
1 The Sixth Environment Action Programme of <strong>the</strong> European Community 2002-2012, http://ec.europa.eu/environment/newprg/index.htm<br />
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Construction and Demolition waste is largely comprised of mineral waste, with small amounts of wood,<br />
plastics and metals. Most investigation of this waste stream has focused on recycling <strong>the</strong> mineral<br />
proportion in<strong>to</strong> aggregate. Of <strong>the</strong> three controlled waste streams this one produces <strong>the</strong> greatest <strong>to</strong>nnage<br />
of waste, but has little or no fuel content.<br />
Bio-solids are produced from waste water treatment sites, as <strong>the</strong> main <strong>by</strong>-product. Data quality is<br />
generally good and in 2004/5 1.72 Mt of dry bio-solids was produced. Estimates are that this will increase<br />
<strong>to</strong> 2.5 Mt <strong>by</strong> 2030 due <strong>to</strong> an increasing number of households and tighter waste water and pollutions<br />
controls through legislation.<br />
Agricultural residues include manures and slurries, and straw and poultry litter. Levels of available<br />
straw (after traditional uses) for 2006 were estimated <strong>to</strong> be 2.9 million <strong>to</strong>nnes for <strong>the</strong> UK, while poultry<br />
litter with an energy content of 37 million GJ was produced. Manures and slurries from cattle were<br />
estimated <strong>to</strong> produce a <strong>to</strong>tal, collectable, 9.9 million kilograms per day of volatile solids, pigs 669<br />
thousand kilograms per day of volatile solids and fowls 1.8 million kilograms per day of volatile solids.<br />
Accurate current and future arisings are difficult <strong>to</strong> predict as <strong>the</strong> sec<strong>to</strong>r is highly dependent on wea<strong>the</strong>r,<br />
farming practices and markets. Residues are usually recycled <strong>to</strong> land apart from poultry litter, that is<br />
al<strong>read</strong>y approximately 50 percent is committed <strong>to</strong> energy from waste plants, and a small proportion of<br />
cereal<br />
Forestry residues arise from forests and woodlands, primary processing co-products and arboricultural<br />
work. Total available forestry residues in <strong>the</strong> UK are estimated <strong>to</strong> be 1,987,000 odt per annum, although<br />
it is unlikely this <strong>full</strong> amount could be realised for energy, and <strong>the</strong> data quality is generally uncertain.<br />
Some future estimations show an increase of material available, but no significant changes are expected.<br />
Not all waste is suitable as a renewable fuel and some waste streams contain only a proportion of<br />
material that could be used as fuel. Figure 1 illustrates <strong>the</strong> <strong>to</strong>tal quantities of waste from each of <strong>the</strong><br />
streams above and <strong>the</strong> <strong>to</strong>tal content of materials that could be used for energy.
Evaluation of Opportunities for Converting Indigenous UK Wastes <strong>to</strong> Fuels and Energy<br />
AEA/ED45551/Issue 1<br />
Total MSW<br />
34,400,000 <strong>to</strong>nnes pa<br />
Total C&I<br />
82,600,000 <strong>to</strong>nnes pa<br />
Total C&D<br />
118,600,000 <strong>to</strong>nnes pa<br />
Bio-solids<br />
1,720,000 <strong>to</strong>nnes pa<br />
Figure 1 Total Waste Arisings for <strong>the</strong> UK<br />
Estimated Food<br />
12,325,000 <strong>to</strong>nnes pa<br />
Estimated Paper and<br />
board<br />
26,309,000 <strong>to</strong>nnes pa<br />
Estimated Wood from<br />
all waste sources<br />
10,541,000 <strong>to</strong>nnes pa<br />
Agricultural Residues<br />
Total Manure 12,400,000t pa<br />
Straw 2,912,000t pa after<br />
traditional uses have been taken in<strong>to</strong><br />
account<br />
Forestry Residues<br />
1,987,000 odt pa<br />
After traditional uses have been taken in<strong>to</strong><br />
account<br />
As is apparent from <strong>the</strong>se figures <strong>the</strong>re is a very substantial amount of potential fuel available in <strong>the</strong><br />
waste arisings from <strong>the</strong> UK. Clearly not all of <strong>the</strong>se are immediately available for energy production and<br />
many fac<strong>to</strong>rs can influence <strong>the</strong> amount of renewable energy that waste can contribute:<br />
• recycling is increasing rapidly and will reduce <strong>the</strong> availability of wood and paper;<br />
• pressure <strong>to</strong> reduce landfill <strong>to</strong> meet EU directives may result in take up of <strong>the</strong> more proven options<br />
of mass burn combustion with energy recovery, and composting, ra<strong>the</strong>r than more innovative<br />
approaches that could offer a higher energy return but require time <strong>to</strong> become established;<br />
• <strong>the</strong> Renewables Obligation could drive cleaner waste resources <strong>to</strong>ward electricity generation<br />
ra<strong>the</strong>r combined heat and power and o<strong>the</strong>r more resource efficient applications.<br />
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These fac<strong>to</strong>rs and how waste is collected and used generally are controlled <strong>to</strong> an overwhelming degree<br />
<strong>by</strong> legislation and incentives. The European Commission determine <strong>the</strong> broad direction of policy and<br />
fur<strong>the</strong>r directives and UK legislation determine <strong>the</strong> detail of its execution.<br />
The main measures that will shape <strong>the</strong> industry and encourage <strong>the</strong> generation of energy are:<br />
The Renewables Obligation – rewards electricity generation from electricity for clean biomass wastes<br />
and CHP from all biomass wastes.<br />
Renewable Transport Fuels Obligation – will create a market for renewable transport fuels.<br />
Future heat incentives – will reward <strong>the</strong> production of heat and CHP from renewable waste.<br />
The Landfill Directive – sets legally binding targets for diversion from landfill of organic material from<br />
MSW, national legislation imposes financial penalties for non compliance.<br />
Waste Framework Directive – revised and updated it places an emphasis on carbon-efficient resource<br />
recovery and requires <strong>the</strong> bio-waste fraction of MSW <strong>to</strong> be collected separately <strong>to</strong> enable composting and<br />
digestion.<br />
The long term impact of <strong>the</strong>se measures on <strong>the</strong> flow of waste materials and <strong>the</strong> proportion diverted <strong>to</strong><br />
energy is not clear at present.<br />
1.2 The status of those energy technologies with<br />
improved resource efficiency<br />
An energy system based on <strong>the</strong> use of wastes and biomass is built up as a chain of several operations.<br />
Waste is collected, processed and delivered <strong>to</strong> a generating plant where it can be converted <strong>to</strong> heat,<br />
power or transport fuels. Each step is delivered <strong>by</strong> a different sec<strong>to</strong>r with its own priorities and<br />
constraints.<br />
The technologies that have been explored within this study are:<br />
• Processes for <strong>the</strong> manufacture of solid recovered fuels and o<strong>the</strong>r manufactured fuels.<br />
o Mechanical Biological Treatment<br />
o Mechanical Heat Treatment<br />
o Wood chips and pellet fuels<br />
• Technologies for <strong>the</strong> conversion of waste <strong>to</strong> energy products.<br />
o Combustion technologies<br />
o Anaerobic Digestion<br />
o Hydrolysis<br />
o Gasification<br />
o Pyrolysis<br />
Examining <strong>the</strong> processes that would offer a high energy return from <strong>the</strong> waste fuel we found that this<br />
could be achieved ei<strong>the</strong>r from application in heat and CHP, or <strong>the</strong> use in advanced processes such as<br />
gasification and pyrolysis. Both cases require fuels that have improved properties and consistency<br />
compared with <strong>the</strong> raw state. Consequently we investigated processes for <strong>the</strong> manufacture of fuel<br />
products from waste streams as a key enabling technology. Manufactured fuels can offer <strong>the</strong> following<br />
benefits<br />
• Consistent properties that can be defined and used in contracts making <strong>the</strong> material a tradable<br />
commodity.<br />
• Physical and biological stability that makes longer term s<strong>to</strong>rage possible and can even out<br />
unbalances between <strong>the</strong> constant supply of waste and <strong>the</strong> seasonal demand for energy.<br />
• An opportunity <strong>to</strong> manage <strong>the</strong> properties of <strong>the</strong> fuel <strong>to</strong> achieve optimum performance from <strong>the</strong><br />
energy technology.
Evaluation of Opportunities for Converting Indigenous UK Wastes <strong>to</strong> Fuels and Energy<br />
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We have identified <strong>the</strong> following manufactured fuels on sale or planned in <strong>the</strong> UK.<br />
• Solid recovered fuels. These fuels are produced from mixed wastes from <strong>the</strong> municipal and<br />
commercial stream <strong>by</strong> separating <strong>the</strong> high heating value components.<br />
• Graded waste wood fuels. Waste wood is collected from industry and amenity centres and<br />
graded depending on <strong>the</strong> level of contamination. The grades are <strong>the</strong>n chipped and sold <strong>to</strong> a<br />
specification.<br />
• Clean grade wood chips from virgin materials. Wood residues for forestry and sawmills are<br />
chipped and potentially dried <strong>to</strong> meet a specification.<br />
• Domestic grade wood pellet fuel from saw mill <strong>by</strong>-product. Sawmill residues, in particular<br />
sawdust, is dried and compressed through a die in<strong>to</strong> small cylinders. This fuel is clean, free<br />
flowing and suitable for small scale combustion appliances.<br />
• Industrial grade pellet from forestry, cereal processing residue and clean waste wood.<br />
This is similar <strong>to</strong> <strong>the</strong> domestic pellet but has a higher ash content and larger size.<br />
• Thermochemical fuels. These are chars and pyrolysis oils produced close <strong>to</strong> <strong>the</strong> point of<br />
arising. We also include <strong>to</strong>rrefaction, or high temperature drying in this category.<br />
Following a review of <strong>the</strong> area our conclusions were as follows;<br />
• Processes are commercially available for producing fuels from MSW and C&I waste using <strong>the</strong><br />
heat from composting as <strong>the</strong> energy for drying.<br />
• Processes for <strong>the</strong> production of fuels using <strong>the</strong>rmal energy <strong>to</strong> dry and sterilise waste are currently<br />
being demonstrated and may offer advantages in providing a more consistent product that is<br />
biologically stable for longer periods.<br />
• Standards for fuels derived from MSW are being developed but are not as yet widely used.<br />
• The production of graded wood waste fuels has expanded rapidly in <strong>the</strong> last three years.<br />
Standards and codes are being adopted <strong>by</strong> <strong>the</strong> industry which is aiding acceptance and<br />
development.<br />
• Clean wood fuels are becoming widesp<strong>read</strong> and standards and codes are being adopted <strong>by</strong> <strong>the</strong><br />
industry.<br />
• Fuels prepared using pyrolysis and <strong>to</strong>rrefaction have been proposed but as yet are not<br />
implemented commercially.<br />
• There is no technical constraint for <strong>the</strong> development of this sec<strong>to</strong>r although <strong>the</strong>re are some non<br />
technical barriers remaining concerned with <strong>the</strong> adaptation of codes and standards.<br />
The wide variation in <strong>the</strong> physical and chemical properties of <strong>the</strong> various waste streams has led <strong>to</strong> many<br />
processes being developed and proposed. For example, <strong>the</strong> only energy recovery solution for <strong>the</strong><br />
majority of wet wastes is anaerobic digestion - for dry wastes <strong>the</strong>rmal processes such as combustion are<br />
more suitable. Given <strong>the</strong> wide differences in <strong>the</strong> technologies we chose <strong>to</strong> treat <strong>the</strong> conversion<br />
technologies in three categories; combustion, <strong>the</strong>rmochemical processes, and biological processes.<br />
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Combustion, or incineration is <strong>by</strong> far <strong>the</strong> most common method of extracting energy from solid waste in<br />
most European countries, in ei<strong>the</strong>r untreated form or as a prepared fuel.<br />
Our conclusions following a review of <strong>the</strong> area are as follows;<br />
• Combustion is a well established technology and <strong>the</strong> main technical challenges have been<br />
addressed. Whatever <strong>the</strong> difficulties with <strong>the</strong> properties of <strong>the</strong> fuel engineers have developed<br />
robust solutions that have been proven <strong>to</strong> work commercially at most scales. As a result of this,<br />
combustion remains <strong>the</strong> default technology for heat and power against which all new, more<br />
innovative, options must be measured.<br />
• There seems <strong>to</strong> be a combustion solution for all waste fuels.<br />
• There remains however significant technical uncertainty surrounding <strong>the</strong> impact of <strong>the</strong><br />
composition of <strong>the</strong> waste on <strong>the</strong> performance of <strong>the</strong> heat exchange surfaces, particularly fouling<br />
and corrosion.<br />
• O<strong>the</strong>r barriers remain, such as <strong>the</strong> largely negative public perception of such sites in some<br />
countries, notably <strong>the</strong> UK.<br />
• There are countless examples of combustion practice worldwide on which <strong>to</strong> draw.<br />
The technologies available for conversion of waste <strong>to</strong> heat and power are more widesp<strong>read</strong> than those for<br />
conversion <strong>to</strong> transport fuels, although work is ongoing on advanced conversion for liquid biofuels.<br />
Combustion gasification and pyrolysis all use heat <strong>to</strong> break down <strong>the</strong> structure of <strong>the</strong> feeds<strong>to</strong>ck so that<br />
<strong>the</strong> chemical energy can be released ei<strong>the</strong>r as heat or a fuel product. The conditions in <strong>the</strong> reac<strong>to</strong>r<br />
determine <strong>the</strong> products.<br />
When combustible waste enters a high temperature environment it will first dry and <strong>the</strong>n decompose in<strong>to</strong><br />
volatile gas and char components.<br />
Gasification processes use a limited supply of oxidant; usually air, <strong>to</strong> maintain both combustion<br />
and reducing reactions in <strong>the</strong> same reac<strong>to</strong>r. Most of <strong>the</strong> energy in <strong>the</strong> fuel is transferred in<strong>to</strong> <strong>the</strong><br />
calorific value (CV) of <strong>the</strong> gas leaving <strong>the</strong> reac<strong>to</strong>r. This gas can be burned separately in a boiler,<br />
engine or gas turbine. Alternatively it can be converted <strong>by</strong> a syn<strong>the</strong>sis reaction <strong>to</strong> methane for<br />
injection <strong>to</strong> <strong>the</strong> Natural Gas Grid or liquid fuels for transport.<br />
In a pyrolysis process <strong>the</strong>re is no oxygen and <strong>the</strong> char and volatile gas remain largely<br />
unchanged. The energy in <strong>the</strong> waste is retained in <strong>the</strong> CV of <strong>the</strong> gas and char removed from <strong>the</strong><br />
reac<strong>to</strong>r.<br />
There are a number of perceived advantages that are often quoted <strong>by</strong> gasification and pyrolysis suppliers<br />
as solutions for perceived weaknesses in <strong>the</strong> current market leader – incineration. These claims with our<br />
comment are shown in <strong>the</strong> Table 1 below.<br />
Table 1 Claims for gasification/pyrolysis with comments<br />
Incineration Gasification/pyrolysis Comment<br />
Large (Regional) size and fuel<br />
demand suppresses recycling.<br />
Small volume of hazardous<br />
and <strong>to</strong>xic fly ash.<br />
Bulky residual ash can be<br />
used as a aggregate.<br />
Can be built economically at <strong>the</strong><br />
smaller sizes that can be<br />
integrated in<strong>to</strong> local schemes.<br />
This remains <strong>to</strong> be<br />
demonstrated, but is probably<br />
true.<br />
No dioxin found in fly ash. This seems <strong>to</strong> be valid.<br />
Some options give low volume<br />
compact ash.<br />
Valid. Some incinera<strong>to</strong>rs can give<br />
low volume slag like ash but at a<br />
very high energy cost for ash<br />
melting.
Evaluation of Opportunities for Converting Indigenous UK Wastes <strong>to</strong> Fuels and Energy<br />
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Incineration Gasification/pyrolysis Comment<br />
Poor electrical efficiency and<br />
lack of suitable heat loads<br />
gives poor resource use<br />
efficiency.<br />
Some options can give very high<br />
electrical efficiencies. Smaller<br />
sizes can match heat loads<br />
better. Particularly as <strong>the</strong>se are<br />
often independent of <strong>the</strong> power<br />
supply.<br />
Electricity and or heat only. Some options can be used <strong>to</strong><br />
generate gas or transport fuels.<br />
Very few demonstrations of high<br />
electrical efficiency. Lack of<br />
enthusiasm for CHP.<br />
Installations in wood waste<br />
sec<strong>to</strong>r now making progress.<br />
True at very large scale.<br />
Following our review our conclusions were as follows;<br />
• Gasification technologies are being developed but often encounter severe technical difficulties<br />
when attempting <strong>the</strong> step of using <strong>the</strong> gas for power generation in an engine or gas turbine.<br />
• The robust approach of firing <strong>the</strong> gas in a boiler is proving reliable and a worthwhile innovation.<br />
These units can be produced in smaller sizes than conventional incineration and can be matched<br />
<strong>to</strong> heat loads in CHP and process heating applications <strong>to</strong> give potentially <strong>the</strong> best GHG<br />
abatement potential.<br />
• Gasification as a pre-treatment is likely <strong>to</strong> become more popular in cofiring as genera<strong>to</strong>rs seek <strong>to</strong><br />
increase <strong>the</strong> proportion of biomass in coal fired utility boilers.<br />
• There are few commercial pyrolysis plant operating on waste.<br />
• The use of gasification at very large scale for <strong>the</strong> production of transport fuels or pipeline<br />
methane is attracting increasing attention and is potentially an efficient use of resources.<br />
Biological processes for waste include anaerobic digestion for <strong>the</strong> production of methane fuel gas and<br />
<strong>the</strong> hydrolysis and subsequent fermentation <strong>to</strong> ethanol fuels of <strong>the</strong> hemi-cellulose and cellulose fractions<br />
of lignocellulosic materials.<br />
Following our review of <strong>the</strong>se technologies our conclusions were as follows;<br />
• Anaerobic digestion processes are technically viable and available for most wet waste feeds<strong>to</strong>cks<br />
including sewage bio-solids.<br />
• Using a proportion of food waste is important <strong>to</strong> <strong>the</strong> economics of anaerobic digestion due <strong>to</strong> its<br />
high gas generation potential and gate fee. Manures are bulky and have poor gas potential.<br />
• Digestate disposal is becoming difficult due <strong>to</strong> constraints in nitrogen sensitive areas.<br />
• Composting is a lower cost alternative <strong>to</strong> AD but does not produce energy and can be regarded<br />
as a competi<strong>to</strong>r <strong>to</strong> AD. It is popular with waste managers due <strong>to</strong> <strong>the</strong> cost and its status as a<br />
recovery, ra<strong>the</strong>r than a disposal process. Disposal of compost <strong>to</strong> land suffers from <strong>the</strong> same<br />
constraints as AD digestates.<br />
• Hydrolysis and subsequent fermentation <strong>to</strong> alcohol fuels of <strong>the</strong> hemicellulose and cellulose<br />
fractions of lignocellulosic materals is still at <strong>the</strong> research stage although <strong>the</strong>re are plans for<br />
demonstration plants in <strong>the</strong> EU and USA. These are likely <strong>to</strong> be co-located with conventional<br />
grain ethanol facilities.<br />
• Feeds<strong>to</strong>cks are limited at present <strong>to</strong> clean wood and agricultural residues.<br />
• We question whe<strong>the</strong>r it should be a priority for <strong>the</strong> UK at present where clean residues are<br />
relatively expensive and could potentially be used in more efficient ways.<br />
1.3 Risks and barriers <strong>to</strong> deployment<br />
The risks and barriers that are faced when adopting novel technologies can be considerable. In <strong>the</strong> table<br />
below we first identify <strong>the</strong> main risks in deploying <strong>the</strong> technologies described above we <strong>the</strong>n describe in<br />
more detail those that we have classed as high or medium.<br />
11
Table 2 Summary of Technologies and <strong>the</strong> Risks and Barriers <strong>to</strong>wards adoption.<br />
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Colour of red, yellow or green signifies <strong>the</strong> risk status of <strong>the</strong> technology: red is high risk, yellow is medium risk and green is low risk.<br />
Risks<br />
Technology Technical Social and Planning Financial Regula<strong>to</strong>ry<br />
Mechanical and<br />
Biological<br />
Treatment (MBT)<br />
Mechanical and<br />
Heat Treatment<br />
(MHT)<br />
Low Medium<br />
Not as divisive as an<br />
incinera<strong>to</strong>r but still subject of<br />
concern as a waste<br />
technology.<br />
High<br />
Demonstration projects only at present.<br />
Combustion Low <strong>to</strong> medium<br />
Many commercial installations,<br />
however <strong>the</strong> materials handling aspects<br />
have proved troublesome in <strong>the</strong> UK and<br />
<strong>the</strong>re is a lack of experience.<br />
Agricultural residues and poor quality<br />
wood fuels may give high ash contents<br />
that lead <strong>to</strong> problems with boiler fouling.<br />
Wastes regulated under WID will need<br />
extensive emissions moni<strong>to</strong>ring<br />
equipment.<br />
Medium<br />
Not as divisive as an<br />
incinera<strong>to</strong>r but still subject of<br />
concern as a waste<br />
technology.<br />
High<br />
High where used <strong>to</strong> produce<br />
electricity on a regional basis<br />
as it will be perceived as an<br />
incinera<strong>to</strong>r irrespective of its<br />
efficiency or recycling<br />
credentials<br />
Medium<br />
Requires revenue from sale of<br />
fuel but market not well<br />
established.<br />
Fuel is still classed as a waste<br />
which may give problems with<br />
sale and use, and hence<br />
price.<br />
Standards and agreed<br />
specifications are needed <strong>to</strong><br />
make <strong>the</strong> fuel product a<br />
traded commodity.<br />
Medium<br />
Requires revenue from sale of<br />
fuel but market not well<br />
established.<br />
Fuel is still classed as a waste<br />
which may give problems with<br />
sale and use, and hence<br />
price.<br />
Standards and agreed<br />
specifications are needed <strong>to</strong><br />
make <strong>the</strong> fuel product a<br />
traded commodity.<br />
Medium<br />
Track record of delays in<br />
planning for waste projects<br />
are a disincentive.<br />
Wood and agricultural<br />
residues are normally OK in<br />
normal circumstances<br />
Medium<br />
Fuel is still classed as a waste<br />
which may give problems with<br />
sale and use, and hence price.<br />
The legal status needs <strong>to</strong> be<br />
clarified. Standards would help<br />
<strong>to</strong> clarify definitions.<br />
Medium<br />
Fuel is still classed as a waste<br />
which may give problems with<br />
sale and use hence a reduced<br />
price.<br />
The legal status needs <strong>to</strong> be<br />
clarified. Standards would help<br />
<strong>to</strong> clarify definitions.<br />
Medium<br />
Receives subsidy via <strong>the</strong><br />
Renewables Obligation.<br />
Waste incineration directive<br />
compliance is usually<br />
necessary.<br />
Co-firing waste in a utility boiler<br />
is difficult as it would require <strong>the</strong><br />
reclassification of <strong>the</strong> whole<br />
station as an incinera<strong>to</strong>r<br />
Fly ash may contain dioxin and<br />
be classed as hazardous waste.
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Technology Technical<br />
Risks<br />
Social and Planning Financial Regula<strong>to</strong>ry<br />
Anaerobic Digestion Low<br />
Medium<br />
Low<br />
Medium<br />
Established mature technology with Not as divisive as an<br />
Receives subsidy via <strong>the</strong><br />
operating commercial plant in incinera<strong>to</strong>r but transport of<br />
Renewables Obligation at an<br />
existence.<br />
slurries in rural areas is a<br />
enhanced rate of 2 ROCs under<br />
Limited experience in UK. Recent major issue and focus for<br />
<strong>the</strong> banding arrangements.<br />
incentives may stretch UK suppliers. opposition, as may be large<br />
Policy may change under<br />
Poor reputation from Holsworthy scale transport of food wastes.<br />
installations lifetime although<br />
experience.<br />
current practice is <strong>to</strong> maintain<br />
Sensitive <strong>to</strong> feeds<strong>to</strong>ck composition,<br />
<strong>the</strong> financial position of existing<br />
can be poisoned <strong>by</strong> trace elements.<br />
plant.<br />
The installation is classed as a<br />
waste management operation<br />
and subject <strong>to</strong> regulation as<br />
such which brings additional<br />
costs and responsibility.<br />
Digestate disposal is an<br />
important consideration and a<br />
change of rules could materially<br />
affect <strong>the</strong> operating costs of <strong>the</strong><br />
installation or even prevent<br />
operation.<br />
Hydrolysis High<br />
Medium<br />
High<br />
Medium<br />
The technology remains innovative Process should be no more The combination of<br />
Would require additional<br />
with only small demonstration and difficult <strong>to</strong> implement than a expensive processing and <strong>the</strong> subsidy from Renewable<br />
pilot projects built so far.<br />
biomass power plant. need for good quality transport fuels obligation.<br />
Feeds<strong>to</strong>cks are currently limited <strong>to</strong><br />
feeds<strong>to</strong>ck means that product<br />
clean wood and agricultural<br />
will be more expensive than<br />
residues. Contamination from o<strong>the</strong>r<br />
imported ethanol for some<br />
sources could damage fermentation<br />
time. This may make it<br />
process.<br />
unsuitable for use in <strong>the</strong> UK.<br />
Gasification High<br />
Medium<br />
High<br />
Medium<br />
Local<br />
Very few operating commercial plant Likely <strong>to</strong> be located on an Poor track record of<br />
for power or CHP.<br />
Significant residual risk in gas<br />
cleaning for power production.<br />
industrial site where impacts<br />
can be minimised.<br />
gasification technologies.<br />
Receives subsidy via <strong>the</strong><br />
Renewables Obligation.<br />
13<br />
Status of ash product is unclear<br />
under Waste Incineration<br />
Directive due <strong>to</strong> high carbon<br />
content.
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Technology Technical<br />
Risks<br />
Social and Planning Financial Regula<strong>to</strong>ry<br />
Gasification High<br />
High<br />
High<br />
Medium<br />
Regional Very few operating commercial plant Where process is used Poor track record of<br />
Receives subsidy via <strong>the</strong><br />
for power or CHP.<br />
<strong>to</strong> produce electricity gasification technologies. Renewables Obligation. Status of<br />
Significant residual risk in gas on a regional basis as it<br />
ash product is unclear under Waste<br />
cleaning for power production. will be perceived as an<br />
Incineration Directive due <strong>to</strong> high<br />
Substantially lower risk for gas untried form of<br />
carbon content.<br />
combustion in boilers and process<br />
units.<br />
incinera<strong>to</strong>r.<br />
Gasification Medium<br />
Low<br />
Medium<br />
Medium<br />
National Little experience of biomass For syn gas production Poor track record of<br />
Receives subsidy via <strong>the</strong><br />
gasification for this application but at large scale on a gasification technologies but Renewable transport fuels<br />
substantial coal experience. petrochemical complex. developers are likely <strong>to</strong> be obligation. Risk for change in long<br />
Closely allied <strong>to</strong> refinery practice.<br />
substantial and have track<br />
record of delivery.<br />
lead time for build.<br />
Pyrolysis all scales High<br />
High<br />
High<br />
Medium<br />
Operating commercial plant in Where process is used Few suppliers and uneven Receives subsidy via <strong>the</strong><br />
existence for oil production little <strong>to</strong> produce electricity at track record.<br />
Renewables Obligation.<br />
experience in energy generation. a regional scale where<br />
it may be perceived as<br />
an untried and unsafe<br />
incinera<strong>to</strong>r.<br />
Low for syn gas<br />
production or <strong>the</strong>rmo<br />
chemical fuel<br />
production where it will<br />
be perceived as<br />
ano<strong>the</strong>r industrial<br />
process.
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1.4 Green house gas balances<br />
Life cycle analyses of waste <strong>to</strong> energy chains are complex and contain a range of fac<strong>to</strong>rs that are not<br />
always obvious or apparent. As part of this work we carried out analyses for a selection of routes for food<br />
waste and wood waste using <strong>the</strong> Defra / Environment Agency BEAT <strong>to</strong>ol. We also reviewed o<strong>the</strong>r work<br />
<strong>by</strong> <strong>the</strong> Environment Agency. Our conclusions are as follows:<br />
• Heat applications are <strong>the</strong> most beneficial in terms of GHG abatement followed <strong>by</strong> CHP where <strong>the</strong><br />
heat load is high.<br />
• Transport fuel production <strong>by</strong> means of gasification is predicted <strong>to</strong> be mid range. Methanation<br />
should be very beneficial if <strong>the</strong> high grade heat from <strong>the</strong> exo<strong>the</strong>rmal reaction is <strong>full</strong>y used,<br />
however we have no data on <strong>the</strong>se systems at present.<br />
• Electricity production comes lower in <strong>the</strong> hierarchy as do biological transport fuel processes and<br />
low heat load CHP.<br />
• Those applications that have <strong>the</strong> highest GHG benefit, such as industrial boilers and smaller<br />
CHP, are those that tend <strong>to</strong> use fuels that have consistent properties that can be s<strong>to</strong>red <strong>to</strong> match<br />
fuel supply with energy demand. These findings reinforce our conclusion that solid recovered<br />
fuels and o<strong>the</strong>r manufactured fuels are essential <strong>to</strong> <strong>the</strong> recovery of energy from waste at high<br />
levels of efficiency.<br />
• AD schemes score well due <strong>to</strong> <strong>the</strong> avoidance of methane emissions from landfill however this is<br />
mitigated <strong>to</strong> some extent <strong>by</strong> nitrous oxide emissions from land sp<strong>read</strong>ing of digestate.<br />
1.5 Challenges, issues and <strong>the</strong> role of NNFCC<br />
Throughout this <strong>report</strong> we have identified areas of uncertainty, and specific challenges that need work if<br />
<strong>the</strong> <strong>full</strong> potential of energy from waste is <strong>to</strong> be realised. These are set out in <strong>the</strong> table below. Most of<br />
<strong>the</strong>se are concerned with building business confidence in <strong>the</strong> links between each of <strong>the</strong> technology steps.<br />
Not all of this work will come under NNFCC’s remit but a significant amount is concerned with<br />
coordination of stakeholders and <strong>the</strong> provision of information <strong>to</strong> <strong>the</strong> market.<br />
Those <strong>to</strong>pics we feel are most appropriate for NNFCC initiatives are as follows:<br />
• Improve quality of policy and investment decision making <strong>by</strong> developing an understanding of <strong>the</strong><br />
fit between SRF properties and energy production technologies. What properties does each of<br />
<strong>the</strong> technologies require?<br />
• There is a wide difference in <strong>the</strong> benefits brought <strong>by</strong> various waste <strong>to</strong> energy chains and it is<br />
important that policy support those that contribute <strong>the</strong> most. NNFCC could add value <strong>to</strong> current<br />
and future work <strong>by</strong> developing an evidence base for <strong>the</strong> design and implementation of policy and<br />
a hierarchy of uses for each class of resource based on environmental and social benefits<br />
including life cycle GHG impact.<br />
• To maximise <strong>the</strong> benefits of using waste for energy we will need <strong>to</strong> change current practices<br />
across a wide range of stakeholders. NNFCC could add value <strong>by</strong> developing an understanding of<br />
15
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<strong>the</strong> relative timeframes of structural changes and technology developments necessary <strong>to</strong><br />
maximise implementation.<br />
• Develop a better market understanding of <strong>the</strong> impacts of increased energy usage on alternative<br />
and existing markets for straw and o<strong>the</strong>r residues.<br />
• Municipal and solid waste is being managed using more sustainable technologies. There is<br />
interest in developing <strong>the</strong>se technologies on one site, so that recycling, separation technologies<br />
or mechanical and biological treatment and anaerobic digestion is all integrated. NNFCC could<br />
examine <strong>the</strong> potential energy benefits in such trends and <strong>the</strong> impact <strong>the</strong>y may have on energy<br />
recovery from waste in general.<br />
1.6 System Overview<br />
An energy system based on <strong>the</strong> use of wastes and biomass is built up as a chain of several operations.<br />
Waste is collected, processed and delivered <strong>to</strong> a generating plant where it can be converted <strong>to</strong> heat,<br />
power or transport fuels. Each step is delivered <strong>by</strong> a different sec<strong>to</strong>r with its own priorities and<br />
constraints. The waste management industry prioritises safe and reliable disposal and has in <strong>the</strong> past<br />
selected technologies that guarantee this.<br />
Better matching of resources and end use should result in improved resource use efficiency and GHG<br />
mitigation as CHP installations can be sized <strong>to</strong> match heat loads and higher added value products are<br />
produced in cost effective installations that can use economy of scale.<br />
With <strong>the</strong> exception of conventional incineration all of <strong>the</strong> energy technologies require <strong>the</strong> feeds<strong>to</strong>ck <strong>to</strong> be<br />
treated <strong>to</strong> ensure a measure of consistency of composition and properties. In our opinion <strong>the</strong> conversion<br />
of waste components <strong>to</strong> consistent fuels will be a major fac<strong>to</strong>r in enabling more efficient alternatives <strong>to</strong> be<br />
deployed.
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Figure 2 Material and energy flows and appropriate technology<br />
Arisings Fuels Local scale<br />
applications<br />
MSW<br />
Bio Solids<br />
Commercial &<br />
Industrial<br />
wastes<br />
Forestry<br />
Residues<br />
Agricultural<br />
Residues<br />
Solid recovered<br />
fuels<br />
Graded waste<br />
wood fuel<br />
Clean grade chips<br />
Domestic grade<br />
pellets<br />
Industrial grade<br />
pellet<br />
AD for<br />
CHP and<br />
grid<br />
injection<br />
Commercial<br />
CHP and<br />
District heat<br />
Individual heating<br />
installations<br />
AD for<br />
CHP<br />
Regional scale<br />
applications<br />
Electricity only and<br />
CHP (incineration)<br />
Industrial CHP<br />
Methanation for<br />
grid<br />
Electricity only<br />
Biological 2 nd<br />
gen biofuel<br />
17<br />
National scale<br />
applications<br />
Gasification for<br />
Transport Biofuel<br />
Gasification<br />
and<br />
Methanation for<br />
pipeline gas<br />
Utility co<br />
firing
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Table of contents<br />
1 Executive Summary 4<br />
1.1 The character and extent of <strong>the</strong> waste resource 5<br />
1.2 The status of those energy technologies with improved resource efficiency 8<br />
1.3 Risks and barriers <strong>to</strong> deployment 11<br />
1.4 Green house gas balances 15<br />
1.5 Challenges, issues and <strong>the</strong> role of NNFCC 15<br />
1.6 System Overview 16<br />
Glossary 20<br />
2 Introduction 22<br />
3 UK Waste Arisings 26<br />
3.1 Waste Categories Investigated 26<br />
3.2 Data Sources and Quality 27<br />
3.3 Overall waste arisings in <strong>the</strong> UK 28<br />
3.4 Growth Rates and Future Arisings 29<br />
4 Arisings <strong>by</strong> Waste Type 30<br />
4.1 Municipal Solid Wastes (MSW) 30<br />
4.2 Commercial and Industrial Wastes (C&I) 36<br />
4.3 Construction and Demolition (C&D) 41<br />
4.4 Bio-solids 45<br />
4.5 Agricultural Residues and Waste 50<br />
4.6 Forestry Residues 58<br />
4.7 Conclusions 67<br />
5 Arisings of components suitable for energy 69<br />
5.1 Waste Wood 69<br />
5.2 Food Waste 75<br />
5.3 Tallow 79<br />
5.4 Textiles Waste Arising 81<br />
5.5 Paper Waste Arisings 82<br />
5.6 Conclusions 85<br />
6 Waste Management Legislation and Incentives 88<br />
7 Solid recovered fuels and o<strong>the</strong>r fuels manufactured from waste 95<br />
7.1 Technologies for manufacturing fuels 96<br />
8 Supplying Energy from Waste <strong>by</strong> Combustion 108<br />
8.1 Process Description 108<br />
8.2 Review of UK and international waste combustion practice 112<br />
8.3 EfW Potential 121
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8.4 Conclusions for Combustion Technologies 123<br />
9 Biological Processes 126<br />
9.1 Anaerobic Digestion (AD) 126<br />
9.2 Composting - an alternative <strong>to</strong> Anaerobic Digestion 137<br />
9.3 Hydrolysis and fermentation of lignocellulose (Biological 2 nd Generation Biofuel)<br />
140<br />
9.4 Conclusions for Biological Processes 143<br />
10 Thermochemical processes for generating energy 144<br />
10.1 Gasification 145<br />
10.2 Pyrolysis 160<br />
10.3 Conclusions 165<br />
11 Potential GHG Reductions 166<br />
11.1 Scenario 1: Food Waste 167<br />
11.2 Scenario 2: Wood Waste 170<br />
11.3 O<strong>the</strong>r, recent GHG life cycle analyses 171<br />
12 Recommendations and NNFCC’s role 172<br />
Appendices<br />
Appendix 1 Fur<strong>the</strong>r information on Waste Arisings<br />
Appendix 2 Waste Legislation<br />
Appendix 3 MBT Methods<br />
19
Glossary<br />
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Term Definition<br />
AD Anaerobic Digestion<br />
BERR Department for Business, Enterprise & Regula<strong>to</strong>ry Reform<br />
BFB Bubbling Fluidised Bed.<br />
BFM British Furniture Manufacturers<br />
BSE Bovine spongiform encephalopathy<br />
C Controlled waste<br />
C&D Construction and Demolition<br />
C&I Commercial and Industrial<br />
CA Civic Amenity<br />
CAD Centralised Anaerobic Digestion<br />
CEN European Committee for Standardisation<br />
CFB Circulating Fluidised Bed<br />
CHP Combined Heat and Power<br />
CLO Compost Like Output<br />
CNG Compressed Natural Gas<br />
CPI Centre for Process Innovation<br />
CSL Central Science Labora<strong>to</strong>ry<br />
CV Calorific Value<br />
Defra Department for <strong>the</strong> Environment, Food and Rural Affairs<br />
DTI Department for Trade and Industry<br />
EA Environment Agency<br />
EfW Energy from Waste<br />
EPRL Energy Power Resources Limited<br />
EU European Union<br />
EU-ETS European Union Energy Trading Scheme<br />
F Fluidised bed burners<br />
FAME Fatty Acid Methyl Ester<br />
FDF Food and Drink Federation<br />
FIRA Furniture Industry Research Association<br />
FYM Farm Yard Manure<br />
G Grate burner<br />
GDP Gross Domestic Product<br />
GHG Green House Gases<br />
IPPC Integrated Pollution and Prevention Control<br />
LHV Lower Heating Value<br />
MBM Meat and Bone meal<br />
MBT Mechanical Biological Treatment<br />
MHT Mechanical Heat Treatment<br />
MSW Municipal Solid Waste<br />
NC Non-controlled waste<br />
NNFCC National Non Food Crop Centre<br />
NVZ Nitrate Vulnerable Zones<br />
ODPM Office of <strong>the</strong> Deputy Prime Minister<br />
odt Oven Dried Tonnes<br />
OSR Oil seed rape<br />
pa Per annum<br />
PAHs Polycyclic Aromatic Hydrocarbons<br />
PCBs Poly Chlorinated Biphenyl
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PPC Pollution Prevention and Control<br />
R21 Recycling in <strong>the</strong> Twenty First Century<br />
RCEP Royal Commission on Environmental Pollution<br />
RDA Regional Development Agency<br />
REEIO Regional Economy Environment Input Output Model<br />
RESTATS Renewable Energy STATisticS database for <strong>the</strong> UK<br />
ROC Renewables Obligation Certificate<br />
RTFO Renewable Transport Fuel Obligation<br />
SEERAD Scottish Executive Environment Rural Affairs Department<br />
SEPA Scottish Environment Protection Agency<br />
SME Small and Medium sized Enterprises<br />
SNG Substitute Natural Gas<br />
SRF Solid Recovered Fuel<br />
SWMP Site Waste management Plan<br />
Syn-gas Syn<strong>the</strong>sis Gas (comprising principally hydrogen and carbon<br />
monoxide and used as a feeds<strong>to</strong>ck for chemical syn<strong>the</strong>sis.)<br />
TC Fuels Thermochemical Fuels (fuels prepared from pyrolysis or <strong>to</strong>rrefaction<br />
products)<br />
TRADA Timber Research and Development Association<br />
UK United Kingdom<br />
USA United States of America<br />
UWWT Urban Waste Water Treatment<br />
VS Volatile Solids<br />
WGs Working Groups<br />
WID Waste Incineration Directive<br />
WIP Waste Implementation Programme<br />
WRAP Waste and Resources Action Programme<br />
Wt Weight<br />
GJ Giga joules<br />
ha Hectares<br />
kg Kilograms<br />
kT Kilo <strong>to</strong>nnes<br />
Mt Mega <strong>to</strong>nnes<br />
MW Mega Watts<br />
t Tonnes<br />
TWh Tera Watt hours<br />
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2 Introduction<br />
The Prime Minister announced at <strong>the</strong> Labour Conference in September 2008 that he wants <strong>the</strong> current<br />
target of a 60 percent cut in carbon dioxide emissions <strong>by</strong> 2050, <strong>to</strong> be raised <strong>to</strong> 80 percent. He also called<br />
for an end <strong>to</strong> <strong>the</strong> dicta<strong>to</strong>rship of oil and a transformation in our use of energy. Cuts of this magnitude<br />
imply a step change in <strong>the</strong> energy infrastructure of <strong>the</strong> country, and <strong>the</strong> generation of energy and fuels<br />
from waste sources can play a major role in delivering this step change.<br />
The National Non-Food Crops Centre (NNFCC) is <strong>the</strong> UK's national centre for <strong>the</strong> development and<br />
support of renewable materials, technologies and fuels. It was established in 2003, and has al<strong>read</strong>y done<br />
considerable work <strong>to</strong> establish supply chains and markets for <strong>the</strong>se products.<br />
The NNFCC does not currently have a defined policy on waste. In order <strong>to</strong> develop this, it needs an up<strong>to</strong>-date<br />
picture of <strong>the</strong> current waste situation, and <strong>the</strong> opportunities for utilising this waste <strong>to</strong> generate<br />
energy and fuels.<br />
The NNFCC has tasked AEA with delivering such a study, which is an important element in developing its<br />
position in this area. The findings will enable <strong>the</strong> NNFCC <strong>to</strong> develop an appropriate and effective insight<br />
in<strong>to</strong> <strong>the</strong> waste situation and market in <strong>the</strong> UK, and how it might be used as a resource <strong>to</strong> derive energy<br />
and fuels. The NNFCC’s current focus is materials and energy from crops, and as a proportion of <strong>the</strong><br />
UK’s waste arisings originate from agricultural activities, <strong>the</strong> opportunity <strong>the</strong>refore exists <strong>to</strong> develop a<br />
strong and coherent position on <strong>the</strong> utilisation of <strong>the</strong>se wastes <strong>to</strong> generate energy and fuels.<br />
Sustainable development is a cause for increasing concern within <strong>the</strong> waste sec<strong>to</strong>r. The main concerns<br />
are focussed around:<br />
• global warming methane gas from landfill sites;<br />
• natural resource depletion, and;<br />
• local environmental pollution <strong>to</strong> land, water and air.<br />
The outcome of <strong>the</strong>se concerns has been <strong>the</strong> recognition at international, European and national levels<br />
that large-scale reliance on landfilling of waste is unsustainable. This has resulted in <strong>the</strong> introduction of<br />
legislation at both European and national levels that promotes a waste treatment hierarchy that places of<br />
waste prevention and minimisation as <strong>the</strong> most desirable option and disposal <strong>to</strong> landfill <strong>the</strong> least. This<br />
hierarchy is set out in <strong>the</strong> well known diagram below.
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Figure 3 Waste hierarchy 2<br />
In <strong>the</strong> current waste hierarchy, energy generation is one form of recovery. Such a classification<br />
recognises that many of <strong>the</strong> o<strong>the</strong>r options are, at present, more resource efficient than <strong>the</strong> technologies<br />
used <strong>to</strong> produce energy from waste. However, it is recognised that such classifications may alter in <strong>the</strong><br />
future as technologies that have better resource efficiencies become available. This <strong>report</strong> identifies <strong>the</strong>se<br />
technologies, outlines <strong>the</strong>ir potential and explores <strong>the</strong> barriers that may stand in <strong>the</strong> way of adoption.<br />
Anaerobic digestion, pyrolysis and gasification are typical of <strong>the</strong>se technologies and have <strong>the</strong> potential <strong>to</strong><br />
be more resource efficient ways of extracting energy and higher value products from waste. This can be<br />
in <strong>the</strong> form of electricity, combined heat and power, methane for transport fuel or grid injection, chemicals<br />
and liquid transport fuels. Although progress has been identified in <strong>the</strong> UK and elsewhere <strong>the</strong>se<br />
technologies remain technically less well developed than conventional methods and may demand a<br />
degree of upstream fuel preparation that will be innovative in <strong>the</strong> UK.<br />
To fulfil <strong>the</strong> objectives of <strong>the</strong> task set for this study we <strong>the</strong>refore need <strong>to</strong> understand a number of aspects<br />
of <strong>the</strong> current and future waste industry. The most important are<br />
• <strong>the</strong> character and extent of <strong>the</strong> waste resource,<br />
• <strong>the</strong> status of those energy technologies with improved resource efficiency,<br />
• <strong>the</strong> demands <strong>the</strong>y place on upstream waste management,<br />
• and <strong>the</strong> benefits that <strong>the</strong>ir adoption might bring.<br />
Our <strong>report</strong> is <strong>the</strong>refore structured as follows:<br />
Waste Arisings<br />
It is important <strong>to</strong> establish a baseline for <strong>the</strong> arisings of waste in <strong>the</strong> UK, particularly on a regional basis,<br />
as many of <strong>the</strong> potential solutions will require stable, locally sourced feed s<strong>to</strong>cks for a considerable<br />
number of years.<br />
Total arisings for <strong>the</strong> three categories of controlled wastes are well recorded, for Municipal Solid Waste<br />
(MSW), Commercial and Industrial waste (C&I) and Construction and Demolition waste (C&D). Within<br />
<strong>the</strong>se categories <strong>the</strong> composition proportions have been <strong>the</strong> focus of a number of studies, particularly for<br />
MSW. Wastes that do not fall within <strong>the</strong>se categories are less well recorded and studied, and<br />
consequently less accurate arisings figures are generated.<br />
2 Image taken from Waste in Context, Select Committee on Science and Technology Sixth Report, July 2008,<br />
http://www.publications.parliament.uk/pa/ld200708/ldselect/ldsctech/163/16305.htm<br />
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The waste arisings chapters have been set out as follows:<br />
• Chapter 3: UK Waste Arisings<br />
A summary of <strong>the</strong> UK waste categories in general and sub-categories frequently cited as suitable<br />
for conversion.<br />
• Chapter 4: Waste Arisings <strong>by</strong> Type<br />
A discussion of arisings on a regional basis of <strong>the</strong> main waste categories including MSW, C&I,<br />
C&D, Bio-solids, Agricultural Residues and Forestry Residues.<br />
• Chapter 5: Arisings of components suitable for energy<br />
An exploration of <strong>the</strong> waste materials commonly quoted as suitable <strong>to</strong> recover energy, but sp<strong>read</strong><br />
over a range of waste streams, including waste wood, waste food, tallow, textiles and paper and<br />
board.<br />
• Chapter 6: Waste Management Legislation and Incentives<br />
Legislation and incentives that affect <strong>the</strong> generation and treatment of wastes.<br />
Technology Options<br />
Chapters 7 <strong>to</strong> 10 describe how <strong>the</strong> waste can be converted <strong>to</strong> energy. They cover processes that supply<br />
heat, electricity, transport fuels and methane for injection <strong>to</strong> <strong>the</strong> national transmission system. These<br />
technologies are available at a range of sizes that make <strong>the</strong>m suitable for many locations and end users.<br />
The physical and chemical properties of <strong>the</strong> waste often determine <strong>the</strong> solution used for waste<br />
management. For example, at <strong>the</strong> moment <strong>the</strong> only energy recovery solution for <strong>the</strong> majority of wet<br />
wastes is anaerobic digestion. For dry wastes (e.g. waste wood) <strong>the</strong>rmal processes such as combustion<br />
are <strong>the</strong> best solution at present.<br />
The technology chapters have been set out as follows:<br />
• Chapter 7: Solid recovered fuels and o<strong>the</strong>r fuels manufactured from waste<br />
Processes and products that transform waste in<strong>to</strong> consistent tradable products.<br />
• Chapter 8: Energy from Waste using conventional <strong>the</strong>rmal processes<br />
Combustion for heat, combined heat and power and power only. Also co-firing with coal in a<br />
utility boiler.<br />
• Chapter 9: Energy from Waste using Biological Processes<br />
Anaerobic Digestion <strong>to</strong> produce power, CHP and gas for injection in<strong>to</strong> <strong>the</strong> national gas grid, with a<br />
comparison <strong>to</strong> composting, and <strong>the</strong> hydrolysis and fermentation of lignocellulosic material <strong>to</strong><br />
produce alcohols for transport fuels.<br />
• Chapter 10: Gasification and Pyrolysis processes for <strong>the</strong> generation of energy<br />
Thermal gasification for subsequent methanation and injection in<strong>to</strong> <strong>the</strong> national grid at both high<br />
and low pressures and gasification and pyrolysis for conversion <strong>to</strong> transport fuels or methane.<br />
Each chapter gives a brief description of <strong>the</strong> main technologies, with an indication of technical status,<br />
scale of operation, risks and barriers <strong>to</strong> deployment and <strong>by</strong>-products. Following this description we<br />
discuss <strong>the</strong> UK market situation and give examples of domestic and international practice. The rationale<br />
for <strong>the</strong> content is given below<br />
Chapter 11 considers two different waste materials, food waste and wood waste, and explores <strong>the</strong> GHG<br />
savings that could be achieved if <strong>the</strong>y were converted <strong>to</strong> energy ra<strong>the</strong>r than disposed of in <strong>the</strong> current<br />
way.<br />
Chapter 12 sets out our proposals <strong>to</strong> NNFCC for <strong>the</strong>ir possible future role in this area. Throughout <strong>the</strong><br />
<strong>report</strong> we identify areas of uncertainty, and specific challenges that need work if <strong>the</strong> <strong>full</strong> potential of<br />
energy from waste is <strong>to</strong> be realised. We believe NNFCC are ideally placed <strong>to</strong> contribute in a number of<br />
ways <strong>to</strong> facilitate <strong>the</strong>se changes.
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System Overview<br />
An energy system based on <strong>the</strong> use of wastes and biomass is built up as a chain of several operations.<br />
Waste is collected, processed and delivered <strong>to</strong> a generating plant where it can be converted <strong>to</strong> heat,<br />
power or transport fuels. Each step is delivered <strong>by</strong> a different sec<strong>to</strong>r with its own priorities and<br />
constraints.<br />
With <strong>the</strong> exception of conventional incineration all of <strong>the</strong> energy technologies require <strong>the</strong> feeds<strong>to</strong>ck <strong>to</strong> be<br />
treated <strong>to</strong> ensure a measure of consistency of composition and properties. In our opinion <strong>the</strong> conversion<br />
of waste components <strong>to</strong> consistent fuels will be a major fac<strong>to</strong>r in enabling more efficient alternatives <strong>to</strong> be<br />
deployed. We have <strong>the</strong>refore included a chapter describing <strong>the</strong> technologies used <strong>to</strong> manufacture <strong>the</strong>se<br />
fuels.<br />
Technical status<br />
The waste management industry prioritises safe and reliable disposal and has in <strong>the</strong> past selected<br />
technologies that guarantee this. Whilst for completeness we describe <strong>the</strong>se more conventional solutions<br />
this <strong>report</strong>, concentrates more on wastes as a resource from <strong>the</strong> point of view of energy and looks in<br />
more detail at those technologies with higher levels of energy efficiency.<br />
Scale of operation<br />
We consider that energy conversion technologies fall in<strong>to</strong> three broad categories depending on <strong>the</strong>ir scale<br />
of operation:<br />
Local, where <strong>the</strong> output is typically less than 2 MW and supplies small premises and industries.<br />
These operations are suitable for bulky or wet wastes or for smaller energy users that can use<br />
clean feeds<strong>to</strong>cks that do not bring with <strong>the</strong>m additional costs for regula<strong>to</strong>ry compliance or<br />
pollution control equipment. Typical technologies in this category are anaerobic digestion, and<br />
combustion for heat and small CHP.<br />
Regional where <strong>the</strong> output is typically less than 50MW and supplies major users, district heating<br />
networks and national electricity and gas networks at <strong>the</strong> distribution level. These operations are<br />
suitable for most wastes and include traditional incineration of municipal wastes. O<strong>the</strong>r<br />
technologies would be industrial scale CHP using combustion or gasification, merchant power<br />
stations and gasification and subsequent methanation for injection in<strong>to</strong> <strong>the</strong> natural gas distribution<br />
network at low pressure. Fuel supplies will typically be upgraded waste fuels and agricultural<br />
residues.<br />
National, where <strong>the</strong> output is typically over 50MW and supplies transport fuel and grid connected<br />
syn<strong>the</strong>tic natural gas and electricity. They are major infrastructure projects located on industrial<br />
complexes. The need <strong>to</strong> transport and s<strong>to</strong>re large quantities of fuel restricts <strong>the</strong> choice <strong>to</strong><br />
relatively dense products. Co-firing at a utility coal fired station also comes in this category.<br />
Risks and barriers<br />
Innovative processes in <strong>the</strong> waste management market face a wide range of technical and non technical<br />
risks and barriers <strong>to</strong> deployment. For each technology we discuss <strong>the</strong>se and <strong>the</strong> relationship with <strong>the</strong><br />
technical status.<br />
Examples of UK and international practice<br />
Many countries are ahead of <strong>the</strong> UK in implementing new technologies and <strong>the</strong>re is much <strong>to</strong> learn.<br />
Consequently we describe examples that demonstrate <strong>the</strong> application of new or strategically important<br />
technologies for energy from waste.<br />
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3 UK Waste Arisings<br />
In this chapter we bring <strong>to</strong>ge<strong>the</strong>r <strong>the</strong> current overall estimates of how much waste is produced annually in<br />
<strong>the</strong> UK, its composition and source. These basic figures are fundamental <strong>to</strong> an understanding of <strong>the</strong><br />
energy potential of <strong>the</strong> waste resource and <strong>the</strong> types of technologies that could be used <strong>to</strong> access it. We<br />
also discuss future trends and a methodology of waste categorisation that is more appropriate for energy<br />
use.<br />
3.1 Waste Categories Investigated<br />
The UK Government and <strong>the</strong> EU commonly group waste arisings in<strong>to</strong> <strong>the</strong> following categories:<br />
• Municipal Solid Waste (MSW)<br />
• Commercial and Industrial (C&I)<br />
• Construction and Demolition (C&D)<br />
• Bio-Solids (previously known as Sewage Sludge)<br />
• Agricultural Wastes<br />
• Dredged material<br />
• Minerals (Mining and Quarrying)<br />
While this level of breakdown is useful for identifying quantities and trends, it does not provide a break<br />
down for many of <strong>the</strong> waste streams that are of particular interest for this study.<br />
In this study <strong>the</strong> wastes that have been identified as having <strong>the</strong> potential for conversion <strong>to</strong> fuels and<br />
energy have been subdivided as follows:<br />
• Municipal Solid Wastes (MSW)<br />
• Commercial and Industrial wastes (C&I)<br />
• Construction and Demolition (C&D)<br />
• Bio-Solids (Sewage Sludge)<br />
• Agricultural<br />
o Wet residues<br />
o Dry residues<br />
• Forestry Residues<br />
Mineral and dredging wastes have not been covered, as <strong>the</strong>se waste streams have no practicable<br />
content that would be available for conversion <strong>to</strong> energy or fuels.<br />
A range of waste materials that are highly suitable for energy but <strong>the</strong>ir arisings are dispersed over several<br />
categories. An emerging trend is <strong>to</strong> combine resources from several streams as feeds<strong>to</strong>ck for an energy<br />
plant. We have considered <strong>the</strong>se dispersed arisings as a set of new subcategories. These are:<br />
• Food waste – arising from MSW and C&I waste<br />
• Wood waste – arising from MSW, C&I waste and C&D waste<br />
• Tallow – arising from C&I waste<br />
• Textile – arising from MSW and C&I waste<br />
• Paper and board – arising from MSW and C&I waste.<br />
In <strong>the</strong> following Sections <strong>the</strong>se waste streams and materials have been described in terms of a definition,<br />
<strong>the</strong> composition of each stream, and <strong>the</strong> arisings <strong>by</strong> region.
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3.2 Data Sources and Quality<br />
The information on waste arisings in this study has been obtained for a wide range of sources, such as<br />
<strong>the</strong> surveys conducted <strong>by</strong> <strong>the</strong> Environment Agency (EA) in England and Wales, and <strong>the</strong> Scottish<br />
Environmental Protection Agency in Scotland, National Agricultural Surveys, publicly available <strong>report</strong>s<br />
from <strong>the</strong> UK Government and Devolved Administrations, as well as many <strong>report</strong>s and surveys carried out<br />
<strong>by</strong> waste action groups. The specific data source is detailed and referenced at <strong>the</strong> point of discussion.<br />
Across <strong>the</strong> UK information on different types of waste is collected for a variety of reasons, and so data for<br />
one type of waste may not be directly comparable with ano<strong>the</strong>r type. For example data on MSW arisings<br />
is collected from <strong>the</strong> point of view of <strong>the</strong> source of arisings and management of <strong>the</strong> waste. Meanwhile<br />
some commercial and industrial wastes have data collected only from waste that has been treated, as <strong>the</strong><br />
treatment facility is registered. So <strong>the</strong>re are waste arisings potentially going unrecorded. It would be fair<br />
<strong>to</strong> say that, understandably, waste data has always been collected from <strong>the</strong> point of view of disposal as a<br />
nuisance ra<strong>the</strong>r than as an energy resource.<br />
The UK Government has recognised that a lack of information on <strong>the</strong> arisings of specific waste streams<br />
and <strong>the</strong>ir growth rates is hampering both <strong>the</strong> development of an effective waste strategy for household<br />
and o<strong>the</strong>r waste streams and <strong>the</strong> ability <strong>to</strong> measure and moni<strong>to</strong>r progress effectively. Consequently, as<br />
part of <strong>the</strong> Waste Implementation Programme (WIP), work on obtaining better data is being taken forward<br />
jointly with <strong>the</strong> Environment Agency <strong>to</strong> provide a sound evidence base for improved waste management<br />
policy development, implementation, moni<strong>to</strong>ring and evaluation at both national and local levels. 3<br />
The first part of WIP, which has al<strong>read</strong>y been implemented, is Waste Data Flow, which will provide<br />
quarterly data on arisings and management of municipal solid waste. The next phase is <strong>the</strong> Waste Data<br />
Strategy, which will include data on both commercial and industrial waste and construction and demolition<br />
waste, and started <strong>to</strong> produce data during 2007. A central principle of <strong>the</strong> data strategy is that costly<br />
surveys should be replaced wherever possible <strong>by</strong> better use of administrative data. In particular, better<br />
use should be made of data received <strong>by</strong> <strong>the</strong> Environment Agency from waste opera<strong>to</strong>rs as part of <strong>the</strong>ir<br />
permit requirements. The final phase will address agricultural, forestry, fishing, mines and quarries<br />
wastes, bio-solids and dredging spoils.<br />
Large scale industrial sites are covered <strong>by</strong> PPC (Pollution Prevention and Control permit), and <strong>the</strong><br />
Environment Agency has a list of all of <strong>the</strong>se sites, which include large scale incinera<strong>to</strong>rs and waste<br />
treatment facilities. PPC also covers recycling facilities, such as paper mills. The PPC thresholds for<br />
treatment plants (chemical, biological, <strong>the</strong>rmal) are 10 <strong>to</strong>nnes per day for hazardous waste and 50 <strong>to</strong>nnes<br />
per day for non-hazardous waste. Waste management licences cover facilities with lower capacities.<br />
The Environment Agency collect data from all facilities that have a waste management license. As <strong>the</strong>se<br />
include all landfill sites, <strong>the</strong>n good quality data on <strong>the</strong> amount of waste landfilled is available. However,<br />
<strong>the</strong>re are a number of gaps in <strong>the</strong> data on amount of material recycled. For example:<br />
• Paper merchants are exempt from Waste Management Licensing and are not required under<br />
<strong>the</strong> regulations <strong>to</strong> provide data.<br />
• Not all paper mills are covered <strong>by</strong> PPC, and PPC facilities currently do not have <strong>to</strong> provide<br />
data on <strong>the</strong> inputs of materials processed (if <strong>the</strong> paper mill is registered as an accredited<br />
reprocessor under <strong>the</strong> Packaging Regulations, <strong>the</strong>n data on <strong>the</strong> amount of packaging<br />
processed are available)<br />
• No data are collected on green list wastes (such as paper), which are exported for recycling<br />
from England and Wales (however, data on exported packaging are available).<br />
3 Delivering Data for Moni<strong>to</strong>ring Waste Strategy 2007, Defra 2008,<br />
http://www.defra.gov.uk/environment/statistics/wastedatahub/download/delivering_data_for_moni<strong>to</strong>ring_wastestrat07.pdf<br />
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There is also little data on <strong>the</strong> amount of C&D waste used at licensed exempt sites (sites which are<br />
registered as exempt from waste licensing requirements). 4 However, changes in PPC requirements<br />
mean that all sites will have <strong>to</strong> provide data on waste inputs, and proposed changes will require <strong>report</strong>ing<br />
of data on <strong>the</strong> amount of C&D waste used at registered exempt sites. These changes will improve <strong>the</strong><br />
quality of data on <strong>the</strong> amount of waste recycled when <strong>the</strong>y have been <strong>full</strong>y implemented, and <strong>to</strong>ge<strong>the</strong>r<br />
with o<strong>the</strong>r changes, should improve <strong>the</strong> overall quality of data on arisings of both C&I and C&D waste <strong>by</strong><br />
2012.<br />
3.3 Overall waste arisings in <strong>the</strong> UK<br />
The most recent and accurate UK wide estimates for waste arising are for 2004 and 2005. The <strong>to</strong>tal<br />
figure for 2004 is 335 million <strong>to</strong>nnes of waste, 5 while estimates for 2005 put <strong>the</strong> figure at 307 million<br />
<strong>to</strong>nnes of waste. 6 Figure 4 shows <strong>the</strong> estimated proportion produced <strong>by</strong> each sec<strong>to</strong>r. This includes nearly<br />
100 million <strong>to</strong>nnes of minerals waste from mining and quarrying, which is not subject <strong>to</strong> control under <strong>the</strong><br />
EU Waste Framework Directive, and 220 million <strong>to</strong>nnes of controlled wastes from households, commerce<br />
and industry (including construction and demolition wastes). Household wastes represent about 9 percent<br />
of <strong>to</strong>tal arisings.<br />
Figure 4: Arisings of waste in <strong>the</strong> UK in 2004<br />
Estimates shown in <strong>the</strong> chart are mainly based on data for 2004 except for estimates of bio-solids which<br />
relate <strong>to</strong> 2005 and construction and demolition waste which relate <strong>to</strong> 2002/03. The figure for construction<br />
and demolition wastes includes excavated soil and miscellaneous materials as well as hard materials,<br />
such as brick, concrete and road planings.<br />
4 Registered Exempt sites are sites which are notified <strong>by</strong> <strong>the</strong> site opera<strong>to</strong>r as being exempt from waste management licensing (though not exempt from<br />
waste regulation) and where this exemption has been placed on <strong>the</strong> public register <strong>by</strong> <strong>the</strong> Environment Agency.<br />
5 Key facts about Waste and Recycling, Defra, http://www.defra.gov.uk/environment/statistics/waste/kf/wrkf02.htm<br />
6 Defra Environmental Statistics, www.defra.gov.uk/environment/statistics/waste/download/xls/wsr_data_2006.xls
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Wastes from mining, quarrying, and dredged material contain no usable material and will not be<br />
considered fur<strong>the</strong>r in this <strong>report</strong>.<br />
Waste from <strong>the</strong> agriculture sec<strong>to</strong>r represents less than 1% of <strong>to</strong>tal arisings. This waste, which excludes<br />
manures or straw, and covers items such as packaging, silage plastics and unused pesticides, came<br />
under <strong>the</strong> same legislative controls as o<strong>the</strong>r controlled wastes in May 2006. The arisings of manure and<br />
slurry were estimated as 45 million <strong>to</strong>nnes in 2002/03. If this waste is included in <strong>to</strong>tal waste arisings,<br />
<strong>the</strong>n <strong>the</strong> <strong>to</strong>tal amount of waste produced in <strong>the</strong> UK in 2004 was 380 million <strong>to</strong>nnes.<br />
O<strong>the</strong>r wastes, which include forestry wastes and fishing wastes, represent about 1% of <strong>to</strong>tal waste<br />
arisings.<br />
Table 3 presents <strong>the</strong> most recent published data for arisings of MSW, C&I waste and C&D waste in<br />
England, Wales 7 , Scotland and Nor<strong>the</strong>rn Ireland. The <strong>to</strong>tal arisings of <strong>the</strong>se waste streams is 236 million<br />
<strong>to</strong>nnes per annum. England produced 79% of <strong>the</strong> <strong>to</strong>tal arisings of <strong>the</strong>se waste streams, and MSW<br />
represents about 15% of <strong>the</strong>se waste streams.<br />
Table 3: Waste arisings (‘000,000 <strong>to</strong>nnes) in <strong>the</strong> UK<br />
England Wales Scotland 8 Nor<strong>the</strong>rn<br />
Ireland<br />
Total<br />
MSW 28.5 9 1.8 10 3.0 1.1 11 34.4<br />
C&I waste 67.9 12 5.3 13 7.8 1.6 14 82.6<br />
C&D waste 89.6 15 12.2 16 11.8 5.0 17 118.6<br />
Total 186.0 19.3 22.6 7.7 235.6<br />
3.4 Growth Rates and Future Arisings<br />
In order <strong>to</strong> plan for future waste management requirements, it is clearly important <strong>to</strong> be able <strong>to</strong> estimate<br />
future waste arisings. These can be determined <strong>by</strong> applying growth rates <strong>to</strong> <strong>the</strong> estimates of current<br />
waste arisings.<br />
His<strong>to</strong>rically, waste arisings have been shown <strong>to</strong> grow in line with, or even above, <strong>the</strong> level of economic<br />
growth. Consequently, if this trend continues, a 3% pa. growth in waste would result a doubling of waste<br />
arisings in 20 years. However, <strong>the</strong> continuation of this trend is now considered <strong>to</strong> be unsustainable, and<br />
thus <strong>the</strong> sixth Environment Action Programme 18 set an objective <strong>to</strong> achieve a decoupling of resource use<br />
from economic growth through significantly improved resource efficiency, dematerialisation of <strong>the</strong><br />
economy and waste prevention.<br />
7 A new survey <strong>to</strong> determine C&I waste arisings in Wales is currently being conducted; <strong>the</strong> findings are expected <strong>to</strong> be published <strong>by</strong> Summer 2009.<br />
8 Waste Data Digest 8: Key facts and trends. Scottish Environmental Protection Agency, 2008<br />
9 Defra - http://www.defra.gov.uk/environment/statistics/wastats/bulletin08.htm<br />
10 Municipal Waste Management Report for Wales, 2007-08. Statistics for Wales, Oc<strong>to</strong>ber 2008<br />
11 Municipal Waste Management Nor<strong>the</strong>rn Ireland 2005/06 Summary Report, December 2006<br />
12 Environment Agency 2006 – Strategic Waste Management Assessment 2002/03<br />
13 Environment Agency Wales, http://www.environment-agency.gov.uk/aboutus/organisation/35675.aspx<br />
14 Commercial & Industrial Waste Arisings Survey 2004/05. Environment & Heritage Service, March 2007<br />
15 Survey of Arisings and Use of Alternatives <strong>to</strong> Primary Aggregates in England, 2005; Construction, Demolition and Excavation Waste. Report for<br />
Department for Communities and Local Government <strong>by</strong> Capita Symonds Ltd, in association with WRc plc, February 2008<br />
16 Survey on <strong>the</strong> arising and management of construction and demolition waste in Wales in 2005-06. Environment agency Wales<br />
17 Construction and demolition waste survey. Environment and Heritage Service (EHS), 2004<br />
18 The Sixth Environment Action Programme of <strong>the</strong> European Community 2002-2012, http://ec.europa.eu/environment/newprg/index.htm<br />
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4 Arisings <strong>by</strong> Waste Type<br />
In this Chapter we consider <strong>the</strong> <strong>to</strong>tal arisings for <strong>the</strong> major wastes and residues on a national and regional<br />
basis. We discuss <strong>the</strong>se in this chapter according <strong>to</strong> <strong>the</strong>ir origin.<br />
The waste streams considered are: Municipal Solid Wastes (MSW); Commercial and Industrial wastes<br />
(C&I); Construction and Demolition (C&D); Bio-solids; Agricultural residues, both Wet and Dry residues,<br />
and; Forestry Residues.<br />
The regional subdivisions used were <strong>the</strong> 9 regional development areas for England, as well as <strong>the</strong><br />
devolved regions of Scotland, Wales and Nor<strong>the</strong>rn Ireland. Where reliable information is available, <strong>the</strong><br />
disposal route used <strong>by</strong> each region for <strong>the</strong> wastes and residues has also been discussed, although <strong>the</strong>re<br />
is little information for many waste streams.<br />
4.1 Municipal Solid Wastes (MSW)<br />
4.1.1 Definition<br />
Municipal Solid Waste, commonly referred <strong>to</strong> as MSW is waste collected <strong>by</strong>, or on behalf of, a local<br />
authority, which has a legal duty <strong>to</strong> manage such wastes. MSW is comprised of:<br />
• household waste<br />
• civic amenity waste<br />
• recycling centre arisings<br />
• street litter<br />
• fly-tipped waste<br />
• commercial waste collected <strong>by</strong> local authorities.<br />
52%<br />
10%<br />
10%<br />
4%<br />
24%<br />
Figure 5 Sources of Municipal Waste<br />
Non-household sources<br />
O<strong>the</strong>r Household<br />
sources<br />
Household recycled<br />
Civic amenity sites
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4.1.2 Composition<br />
As MSW comprises largely of household wastes, a considerable range of materials are included, for<br />
example food waste, garden waste, plastics, metals and paper are commonly present. In addition<br />
domestic hazardous and <strong>to</strong>xic waste may also be present, such as medication, paints, fluorescent tubes,<br />
spray cans, and batteries <strong>to</strong> name only a few. Table 4 shows a detailed breakdown of constituent<br />
materials, taken from a survey conducted in Wales, which could be considered typical of <strong>the</strong> UK. 19<br />
Table 4 Composition of MSW<br />
Waste Category Weight Weight<br />
Suitable for <strong>the</strong>rmal processes<br />
(‘000 <strong>to</strong>nnes) (%)<br />
Newspapers and magazines 147.3 9.0<br />
Recyclable paper 34.0 2.1<br />
Cardboard boxes/containers 84.4 5.1<br />
O<strong>the</strong>r paper and card 79.2 4.8<br />
Refuse sacks and carrier bags 20.5 1.3<br />
Packaging film 22.1 1.3<br />
O<strong>the</strong>r plastic film 3.0 0.2<br />
Dense plastic bottles 27.1 1.7<br />
O<strong>the</strong>r packaging 24.3 1.5<br />
O<strong>the</strong>r dense plastic 22.2 1.3<br />
Textiles 30.3 1.8<br />
Shoes 5.9 0.4<br />
Disposable nappies 37.7 2.3<br />
Wood 46.3 2.8<br />
Carpet and underlay 23.9 1.5<br />
Furniture 24.3 1.5<br />
O<strong>the</strong>r miscellaneous combustibles 59.8 3.6<br />
Total<br />
Suitable for composting or <strong>the</strong>rmal<br />
692.3 42.2<br />
Garden waste<br />
Suitable for AD or composting<br />
208.7 12.7<br />
Kitchen waste 257.1 15.7<br />
O<strong>the</strong>r organics 34.3 2.1<br />
Total<br />
Not suitable for energy recovery<br />
291.4 17.8<br />
Packaging glass 87.0 5.3<br />
Non-packaging glass 8.1 0.5<br />
Ferrous food and beverage cans 27.8 1.7<br />
O<strong>the</strong>r ferrous metal 51.6 3.1<br />
Non-ferrous food and beverage cans 5.6 0.3<br />
O<strong>the</strong>r non ferrous metal 7.7 0.5<br />
White goods 13.9 0.8<br />
Large electronic goods 3.1 0.2<br />
TVs and moni<strong>to</strong>rs 4.8 0.3<br />
O<strong>the</strong>r WEEE 10.9 0.7<br />
Lead/acid batteries 3.7 0.2<br />
Oil 1.0 0.1<br />
Identifiable clinical waste 2.7 0.2<br />
O<strong>the</strong>r potentially hazardous items 5.0 0.3<br />
Construction and demolition waste 85.9 5.2<br />
O<strong>the</strong>r MNC 45.3 2.8<br />
Fines 86.0 5.1<br />
Total 450.1 27.3<br />
As can be seen <strong>the</strong>re are substantial quantities of material that are suitable for energy use ei<strong>the</strong>r <strong>by</strong><br />
<strong>the</strong>rmal processes or anaerobic digestion.<br />
19 The composition of municipal solid waste in Wales. Report <strong>by</strong> AEA for <strong>the</strong> Welsh Assembly Government, December 2003.<br />
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4.1.3 Current Arisings on a National and Regional basis<br />
MSW currently represents approximately 9% of <strong>to</strong>tal waste arisings. Final estimates of municipal waste<br />
arisings and management for England and <strong>the</strong> regions in 2007/8 were published in November 2008. 20<br />
Table 5 shows <strong>the</strong> arisings of MSW in each of <strong>the</strong> English regions in 2007/08. The South East has <strong>the</strong><br />
highest arisings, followed <strong>by</strong> London. The latest MSW arisings data for Nor<strong>the</strong>rn Ireland, Scotland and<br />
Wales are also shown below in Table 5, and allow an overview of <strong>the</strong> UK MSW arisings <strong>to</strong> be presented.<br />
Table 5: MSW arisings in <strong>the</strong> UK <strong>by</strong> region and Country in 2007/08<br />
Region MSW Arisings<br />
(‘000 <strong>to</strong>nnes)<br />
East Midlands 2,413<br />
East of England 3,034<br />
London 4,154<br />
North East 1,512<br />
North West 4,052<br />
South East 4,563<br />
South West 2,929<br />
West Midlands 2,984<br />
Yorkshire and Humber 2,865<br />
England - Total 28,507<br />
Nor<strong>the</strong>rn Ireland 1,100 21<br />
Scotland 3,000 22<br />
Wales 1,800 23<br />
UK - Total 34,400<br />
Although <strong>the</strong> recycling rate has increased (see Table 6), 62% of MSW arisings in England are currently<br />
landfilled. 24<br />
Table 6 MSW Recycling Rate<br />
Year England<br />
(Wt %)<br />
Wales<br />
(Wt %)<br />
Scotland<br />
(Wt %)<br />
Nor<strong>the</strong>rn<br />
Ireland<br />
(Wt %)<br />
2000/01 12.3 - - -<br />
2001/02 14.0 8.4 - -<br />
2002/03 16.0 12.5 8.0 -<br />
2003/04 19.0 17.7 12.1 -<br />
2004/05 23.5 21.7 17.5 18.2<br />
2005/06 27.2 25.5 24.4 23.2<br />
2006/07 30.6 29.9 28.5 25.5<br />
2007/08 34.0 33.6 Report due in Report due in<br />
* Not published yet<br />
2009* 2009*<br />
A significant proportion of MSW is now recycled. The increase in <strong>the</strong> recycling rate is due <strong>to</strong> both<br />
Government recycling targets and <strong>the</strong> need for local authorities <strong>to</strong> meet <strong>the</strong> 2010 target for landfilling<br />
20 Defra Statistical Release 352/08, http://www.defra.gov.uk/environment/statistics/wastats/archive/mwb200708_statsrelease.pdf<br />
21 Municipal Waste Management Nor<strong>the</strong>rn Ireland 2005/06 Summary Report, December 2006<br />
22 Waste Data Digest 8: Key facts and trends. Scottish Environmental Protection Agency, 2008<br />
23 Municipal Waste Management Report for Wales, 2007-08. Statistics for Wales, Oc<strong>to</strong>ber 2008<br />
24 Results from WasteDataFlow http://www.defra.gov.uk/environment/statistics/wastats/bulletin.htm
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biodegradable waste. The increase in recycling rates is mainly due <strong>to</strong> <strong>the</strong> introduction of kerbside<br />
collection schemes for dry recyclable materials (paper, glass, metal and plastic) and garden waste.<br />
Increasing <strong>the</strong> recycling rate <strong>to</strong> <strong>the</strong> 2020 target of 50% will require large-scale collection of food waste<br />
from households; <strong>the</strong> England waste strategy promotes this because of both landfill gas reduction and<br />
energy recovery if food waste is treated using anaerobic digestion.<br />
Table 7 shows <strong>the</strong> arisings and management of MSW in each of <strong>the</strong> English regions in 2007/08. This<br />
table illustrates <strong>the</strong> considerable variations in <strong>the</strong> pattern of waste management as a result of population,<br />
socio economic fac<strong>to</strong>rs and policy. For example, London has <strong>the</strong> lowest recycling rate in percentage<br />
terms but has a high <strong>to</strong>nnage, while <strong>the</strong> South West has <strong>the</strong> highest percentage rate but lower <strong>to</strong>nnage<br />
A <strong>to</strong>tal of about 10 million <strong>to</strong>nnes of MSW arisings in England were ei<strong>the</strong>r recycled or composted in<br />
2007/08.<br />
Table 7 Management of MSW in English regions in 2007/08<br />
Region MSW Arisings<br />
(‘000 <strong>to</strong>nnes)<br />
Recycled or<br />
Composted<br />
(Wt %)<br />
Energy<br />
Recovery<br />
(Wt %)<br />
Landfilled<br />
(Wt %)<br />
East Midlands 2,413 40 7 53<br />
East of England 3,034 40 2 58<br />
London 4,154 22 22 56<br />
North East 1,512 29 13 58<br />
North West 4,052 36 2 62<br />
South East 4,563 37 12 51<br />
South West 2,929 41 - 59<br />
West Midlands 2,984 32 30 38<br />
Yorkshire and Humber 2,865 30 10 60<br />
England - Total 28,507 34 11 55<br />
Nor<strong>the</strong>rn Ireland 1,100 28 - -<br />
Scotland 3,000 32 2 66<br />
Wales 1,800 33 1 65<br />
UK- Total 34,407 127 - -<br />
The amount of waste which is landfilled will reduce due <strong>to</strong> both fur<strong>the</strong>r increases in recycling rate and <strong>the</strong><br />
increasing capacity for waste treatment which will enable local authorities <strong>to</strong> meet <strong>the</strong> 2013 and 2020<br />
targets set <strong>by</strong> <strong>the</strong> Landfill Directive (this will also increase <strong>the</strong> percentage of waste which has energy<br />
recovered from it).<br />
4.1.4 Growth Rates and Future trends<br />
The growth in household waste (and hence MSW) is due <strong>to</strong> two key fac<strong>to</strong>rs:<br />
• An increase in <strong>the</strong> number of households, and<br />
• Growth in waste produced per household due <strong>to</strong> increased consumption.<br />
Waste minimisation and re-use initiatives 25 aim <strong>to</strong> tackle <strong>the</strong> growth in waste produced <strong>by</strong> a household.<br />
However, even if <strong>the</strong>se initiatives were <strong>to</strong> reduce <strong>the</strong> growth in waste per household <strong>to</strong> zero, <strong>the</strong>n arisings<br />
of household waste would still increase as a result of an increase in <strong>the</strong> number of households.<br />
25 International Waste Prevention and Reduction Practice: Final Report. Report <strong>by</strong> Enviros for Defra, Oc<strong>to</strong>ber 2004.<br />
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One European study has assessed <strong>the</strong> fac<strong>to</strong>rs affecting household consumption, and <strong>the</strong> effects on <strong>the</strong><br />
environment (resource use, energy use and waste). 26 Ano<strong>the</strong>r European study developed a model which<br />
assesses <strong>the</strong> effects of food, recreation, ‘infotainment’, care, clothing, and housing on waste growth and<br />
used this <strong>to</strong> model four scenarios which all assumed continued economic growth but had different future<br />
lifestyles. 27 The results of both showed that waste continued <strong>to</strong> grow - sometimes considerably higher<br />
than GDP growth rate, sometimes in line with GDP growth rate, and sometimes at lower than GDP growth<br />
rates.<br />
Data on MSW arisings from a number of European countries from 1997 <strong>to</strong> 2003 indicate that in some<br />
countries (e.g. Belgium and <strong>the</strong> Ne<strong>the</strong>rlands) waste arisings are growing more slowly than GDP growth. 28<br />
The data also suggests that countries that have higher MSW recycling rates are seeing lower growth<br />
rates in MSW arisings; this may be because <strong>the</strong> impacts due <strong>to</strong> many years of publicity/education<br />
information on waste awareness and recycling are now becoming noticeable. However, this trend does<br />
not appear <strong>to</strong> be evident in ei<strong>the</strong>r France or Germany.<br />
Figure 6 shows that <strong>the</strong> arisings of MSW in England increased from 24.6 million <strong>to</strong>nnes in 1996/97 <strong>to</strong> 29.4<br />
million <strong>to</strong>nnes in 2002/03. This represents an average growth rate of about 3% per annum. However,<br />
<strong>the</strong>re has been little growth in arisings since <strong>the</strong>n; <strong>the</strong> overall arisings of 29.1 million <strong>to</strong>nnes in 2006/07<br />
were lower than <strong>the</strong> arisings of 29.4 million <strong>to</strong>nnes in 2002/03, and <strong>the</strong> arisings in 2007/08 reduced <strong>to</strong><br />
28.5 million <strong>to</strong>nnes, which was lower than that in 2001/02.<br />
Million <strong>to</strong>nnes of MSW<br />
35,000<br />
30,000<br />
25,000<br />
20,000<br />
15,000<br />
10,000<br />
5,000<br />
0<br />
1996/97<br />
1997/98<br />
1998/99<br />
1999/2000<br />
2000/01<br />
2001/02<br />
2002/03<br />
Year<br />
2003/04<br />
2004/05<br />
2005/06<br />
Figure 6: MSW arisings (‘000 <strong>to</strong>nnes) in England 1996/97 <strong>to</strong> 2007/08<br />
Although MSW arisings grew at an average of 3% per annum from 1997/98 <strong>to</strong> 2000/2001, <strong>the</strong> average<br />
rate of growth since <strong>the</strong>n is now averaging less than 1% per annum. There are a number of possible<br />
reasons for this lower growth rate:<br />
• Waste minimisation campaigns (<strong>the</strong>se usually take at least 5 years <strong>to</strong> show any noticeable effect)<br />
• Lower arisings of garden waste collected due <strong>to</strong> a combination of dryer summers and an increase<br />
in <strong>the</strong> amount of material that is home composted<br />
• Restrictions placed on <strong>the</strong> types of waste taken <strong>to</strong> <strong>the</strong> household waste recycling centres.<br />
2006/07<br />
26 Household Consumption and <strong>the</strong> Environment. European Environment Agency Report 11/2005.<br />
27 Scenarios of Household Waste Generation in 2020. Report <strong>by</strong> Joint Research Centre for <strong>the</strong> European Commission, June 2003.<br />
28 Eurostat - ec.europa.eu/eurostat<br />
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There are a number of predictions for future MSW arisings:<br />
• A model created <strong>by</strong> <strong>the</strong> Future Foundation in 2006 assessed <strong>the</strong> impact of lifestyle changes on<br />
household waste arisings in <strong>the</strong> UK. 29 This model has a base case scenario in which waste<br />
quantities grow at an average of over 2% per annum from 2005 <strong>to</strong> 2020.<br />
• Ano<strong>the</strong>r model <strong>by</strong> Oakdene Hollins in 2005 predicted future waste arisings based on national<br />
waste strategies and <strong>the</strong> need <strong>to</strong> meet various legislative targets. 30 This model has a base case<br />
growth rate of 2% per annum from 2005 <strong>to</strong> 2020.<br />
These models predict average growth rates of between 1% and 2% per annum, and <strong>the</strong> Waste Strategy<br />
2007 developed four growth scenarios for MSW in order <strong>to</strong> assess a range of possible future outcomes <strong>to</strong><br />
2020:<br />
1. 2.25% per annum reflecting recent trends in growth in consumer spending;<br />
2. 1.5% per annum in line with national waste growth in <strong>the</strong> five years <strong>to</strong> 2004/05;<br />
3. 0.75% per annum, in line with current projections of household growth and reflecting more closely<br />
national waste growth in <strong>the</strong> five years <strong>to</strong> 2005/06; and<br />
4. 0% growth, representing <strong>the</strong> possibility that waste growth will be decoupled from household and<br />
economic growth.<br />
It is unlikely that scenario 4 (0% growth) will occur due <strong>to</strong> Government policy regarding future house<br />
building (even if a waste minimisation programme reduces <strong>the</strong> level of growth of waste in a household <strong>to</strong><br />
0%, <strong>the</strong> arisings of MSW will increase because of <strong>the</strong> increase in <strong>the</strong> number of houses). 31 It is also<br />
unlikely that scenario 1 (2.25% growth) will occur due <strong>to</strong> <strong>the</strong> emphasis on future waste minimisation in <strong>the</strong><br />
new national waste strategy. Consequently, most growth forecasts use growth rates for MSW of 0.75%<br />
per annum as this reflects Scenario 3 in <strong>the</strong> national waste strategy, and this growth rate has been used<br />
<strong>to</strong> estimate future arisings of this stream.<br />
One type of waste that is now covered <strong>by</strong> European and UK legislation with <strong>the</strong> aim of reducing <strong>the</strong><br />
amount sent <strong>to</strong> landfill is biodegradable waste. The intention here is <strong>to</strong> reduce <strong>the</strong> uncontrolled release of<br />
greenhouse gas emissions in<strong>to</strong> atmosphere. The Landfill Directive also requires waste <strong>to</strong> be pre-treated<br />
prior <strong>to</strong> disposal. This has significant implications for energy applications as such waste will be available<br />
as a segregated feeds<strong>to</strong>ck, potentially advantageously pre-treated.<br />
4.1.5 Conclusion<br />
In <strong>to</strong>tal <strong>the</strong> UK produced 34.4 million <strong>to</strong>nnes of MSW in 2008. UK local authorities have significant targets<br />
<strong>to</strong> meet in terms of recording information, segregating and recycling <strong>the</strong> waste and landfill diversion.<br />
Largely due <strong>to</strong> <strong>the</strong>se requirements on <strong>the</strong> local authorities this waste stream is one of <strong>the</strong> best recorded<br />
and unders<strong>to</strong>od.<br />
There has been little growth in <strong>the</strong> volume of MSW produced in <strong>the</strong> UK since 2002, thought <strong>to</strong> be due <strong>to</strong> a<br />
combination of recycling schemes, reduced garden wastes due <strong>to</strong> dryer summers and increased controls<br />
on disposals accepted at civic amenity sites.<br />
MSW contains a wide range of materials, although this range is decreasing as recycling initiatives<br />
become more wide sp<strong>read</strong> and more material diverse. Although recycling rates continue <strong>to</strong> increase<br />
each year overall, 62% of MSW is still currently landfilled in England.<br />
29<br />
Modelling <strong>the</strong> Impact of Lifestyle Changes on Household Waste Arisings in <strong>the</strong> UK. Report <strong>by</strong> <strong>the</strong> Future Foundation and Social Marketing Practice<br />
for Defra 2006.<br />
30<br />
Quantification of <strong>the</strong> Potential Energy from Residuals (EfR) in <strong>the</strong> UK. Report <strong>by</strong> Oakdene Hollins for The Institution of Civil Engineers and The<br />
Renewable Power Association, March 2005.<br />
31 Opinion of internal AEA expert.<br />
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Most growth forecasts use growth rates for MSW of 0.75% per annum as this reflects Scenario 3 in <strong>the</strong><br />
national waste strategy. This suggests that MSW will be a stable source of feeds<strong>to</strong>ck for energy in <strong>the</strong><br />
foreseeable future.<br />
Increasing <strong>the</strong> recycling rate <strong>to</strong> <strong>the</strong> 2020 target of 50% will require large-scale collection of food waste<br />
from households; <strong>the</strong> England waste strategy promotes this because of both landfill gas reduction and<br />
energy recovery if food waste is treated using anaerobic digestion. This is a significant opportunity <strong>to</strong><br />
recover renewable energy.<br />
4.2 Commercial and Industrial Wastes (C&I)<br />
4.2.1 Definition<br />
Commercial and Industrial wastes are those arising from premises used for industry, trade or business.<br />
In 2002/3 Industrial and Commercial waste in England <strong>to</strong>talled 68 million <strong>to</strong>nnes. Of this about 38 million<br />
<strong>to</strong>nnes was attributable <strong>to</strong> industry and 30 million <strong>to</strong> commerce.<br />
4.2.2 Composition<br />
The individual sec<strong>to</strong>r that produced <strong>the</strong> most waste was <strong>the</strong> retail sec<strong>to</strong>r, which generated nearly 13<br />
million <strong>to</strong>nnes of waste. This was followed <strong>by</strong> food, drink and <strong>to</strong>bacco manufacturing, and <strong>the</strong> professional<br />
services and o<strong>the</strong>r businesses, both producing more than 7 million <strong>to</strong>nnes, and <strong>the</strong> coke, oil, gas,<br />
electricity and water industries at just over 6 million <strong>to</strong>nnes.<br />
Table 8 Commercial and Industrial waste arisings 2002-3 for England and Wales<br />
Type of Industrial Waste C&I Arisings<br />
(‘000 <strong>to</strong>nnes)<br />
Manufacture of pulp, paper and paper products 1,800<br />
Food, drink and <strong>to</strong>bacco 7,200<br />
Textiles, lea<strong>the</strong>r goods 1,200<br />
Wood and wood products (inc. furniture) 2,000<br />
Publishing, printing and recording 2,200<br />
Production of coke, electricity, oil, gas and water 6,200<br />
Manufacture of metals, fabricated metal and<br />
machinery and equipment<br />
7,700<br />
Manufacture of mo<strong>to</strong>r vehicles and o<strong>the</strong>r transport<br />
1,500<br />
equipment<br />
O<strong>the</strong>r non-metallic mineral products 2,300<br />
Retail, including mo<strong>to</strong>r vehicles, parts and fuel 12,800<br />
Hotels, catering 3,400<br />
Transport, s<strong>to</strong>rage and communications 2,200<br />
Commercial business, finance, real estate and<br />
7,200<br />
computer related activities<br />
Public administration and social work 1,400<br />
Chemical and o<strong>the</strong>r 5,300<br />
Education 1,900<br />
Miscellaneous 1,500<br />
Total 67.9
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This demonstrates that industrial and commercial wastes contain a vast range of materials, and that<br />
discussing <strong>the</strong>m as a single homogenous mass can be misleading. Table 9 gives more detail about <strong>the</strong><br />
possible content of commercial and industrials wastes, based on an Environment Agency survey covering<br />
England and Wales.<br />
Table 9: Composition (‘000 <strong>to</strong>nnes) of commercial and industrial waste in England<br />
Commercial Industrial Total<br />
Chemicals 1,942 5,692 7,634<br />
Metallic 604 2,727 3,330<br />
Non-metallic 8,651 5,181 13,833<br />
Discarded equipment 262 88 350<br />
Animal & plant 2,152 4,143 6,295<br />
Mixed/general waste 15,569 6,056 21,625<br />
Common sludges 154 761 915<br />
Mineral wastes 987 12,939 13,926<br />
Total 30,320 37,587 67,907<br />
Table 9 shows that:<br />
• Mixed/general waste is <strong>the</strong> largest category, representing 32% of <strong>to</strong>tal C&I arisings (a figure<br />
of 37% was determined for <strong>the</strong> survey in Nor<strong>the</strong>rn Ireland), and 50% of commercial waste<br />
arisings<br />
• Mineral wastes represent about 20% of <strong>to</strong>tal C&I arisings. This includes 6 million <strong>to</strong>nnes per<br />
annum of ash from pulverised coal fired power stations, of which about 3 million <strong>to</strong>nnes is<br />
currently being recycled. 32<br />
• Non-metallic wastes represent about 20% of <strong>to</strong>tal C&I arisings. This category includes<br />
recycled paper/cardboard, and over 85% of <strong>the</strong> <strong>to</strong>tal arisings of this category are recycled.<br />
32 The current classification of pulverised fuel ash as a waste is <strong>the</strong> main reason why only about 50% of it is currently recycled. The Waste Pro<strong>to</strong>cols<br />
Project is currently considering whe<strong>the</strong>r <strong>the</strong> ash could be classified as a product for specified recycling uses<br />
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4.2.3 Current Waste Arisings<br />
Table 10 shows <strong>the</strong> arisings of commercial and industrial waste in each of <strong>the</strong> English regions in 2002/03.<br />
London and <strong>the</strong> South East had <strong>the</strong> highest arisings of commercial waste, and Yorkshire and Humber<br />
had <strong>the</strong> highest arisings of industrial waste.<br />
Table 10: Arisings of commercial and industrial waste <strong>by</strong> English Region and Country in 2002/03<br />
Region Commercial<br />
Waste<br />
(‘000 <strong>to</strong>nnes)<br />
Industrial<br />
Waste<br />
(‘000 <strong>to</strong>nnes)<br />
Commercial and<br />
Industrial Waste<br />
(‘000 <strong>to</strong>nnes)<br />
East Midlands 2,322 5,171 8,093<br />
East of England 3,308 3,256 6,564<br />
London 5,604 1,902 7,507<br />
North East 1,199 3,400 4,599<br />
North West 3,833 4,502 8,335<br />
South East 5,271 3,581 8,852<br />
South West 2,967 2,589 5,556<br />
West Midlands 3,019 4,246 7,265<br />
Yorkshire and Humber 2,797 8,339 11,136<br />
England - Total 30,320 37,587 67,907 33<br />
Nor<strong>the</strong>rn Ireland - - 1,600 34<br />
Scotland - - 7,800 35<br />
Wales - - 5,300 36<br />
UK - Total - - 82,600<br />
Figure 7 demonstrates that <strong>the</strong> amount of commercial and industrial waste sent <strong>to</strong> landfill in 2002/03 was<br />
lower than that landfilled in 1998/99. There has been a small increase in energy recovery since 1998/99,<br />
but most of <strong>the</strong> reduction in <strong>the</strong> amount of waste which was landfilled from 1998/99 is due <strong>to</strong> <strong>the</strong> increase<br />
in <strong>the</strong> amount which was recycled. Such a development is likely due <strong>to</strong> <strong>the</strong> increases in landfill tax (this<br />
will increase <strong>to</strong> £48/<strong>to</strong>nne <strong>by</strong> 2010/11). As indicated in Figure 7, 42% (about 29 million <strong>to</strong>nnes) of<br />
commercial and industrial waste was recycled in England in 2002/03.<br />
Table 11 Arisings of commercial and industrial waste in England<br />
Year Commercial<br />
Waste<br />
(‘000 <strong>to</strong>nnes)<br />
Industrial Waste<br />
(‘000 <strong>to</strong>nnes)<br />
Total Waste<br />
(‘000 <strong>to</strong>nnes)<br />
2002/03 30,300 28,700 59,000<br />
1998/99 23,700 36,000 59,700<br />
33 Environment Agency 2006 – Strategic Waste Management Assessment 2002/03<br />
34 Commercial & Industrial Waste Arisings Survey 2004/05. Environment & Heritage Service, March 2007<br />
35 Waste Data Digest 8: Key facts and trends. Scottish Environmental Protection Agency, 2008<br />
36 Environment Agency, Wales, http://new.wales.gov.uk/resilience/o<strong>the</strong>r-responders1/env-agy-wales/?lang=en
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Figure 7 Management of commercial and industrial waste in England<br />
Table 12 Recycling rates for commercial and industrial waste in English Regions in 2002/03<br />
Region Commercial<br />
Waste<br />
(Wt %)<br />
Industrial<br />
Waste<br />
(Wt %)<br />
Commercial and<br />
Industrial Waste<br />
(Wt %)<br />
East Midlands 37 44 42<br />
East of England 38 45 41<br />
London 41 54 44<br />
North East 34 49 45<br />
North West 32 37 35<br />
South East 30 35 32<br />
South West 35 45 40<br />
West Midlands 40 50 46<br />
Yorkshire and Humber 44 55 52<br />
England – Total 37 47 42<br />
Nor<strong>the</strong>rn Ireland - - 24<br />
Scotland - - -<br />
Wales - - 62*<br />
* recycled / reused<br />
Table 12 shows that:<br />
• Information from Scotland is not available, and that from Wales and Nor<strong>the</strong>rn Ireland is not<br />
split between commercial and industrial.<br />
• The overall recycling rate for industrial waste (47%) is higher than <strong>the</strong> overall recycling rate<br />
(37%) for commercial waste<br />
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• The South East had <strong>the</strong> lowest recycling rates for both commercial waste and industrial<br />
waste<br />
• Yorkshire and Humber had <strong>the</strong> highest recycling rates for both commercial and industrial<br />
waste, and London had <strong>the</strong> second highest recycling rates for both streams.<br />
Most commercial and industrial waste is collected <strong>by</strong> private sec<strong>to</strong>r waste management companies, such<br />
as Sita, Veolia and Viridor. Local authorities have a statu<strong>to</strong>ry obligation <strong>to</strong> collect C&I waste, but <strong>the</strong>y<br />
generally only collect from a proportion of small businesses. Collec<strong>to</strong>rs also provide services <strong>to</strong> collect<br />
recyclable materials, such as paper; this allows businesses <strong>to</strong> demonstrate that <strong>the</strong>ir waste has been<br />
sorted in order <strong>to</strong> comply with <strong>the</strong> requirements of <strong>the</strong> Landfill Directive.<br />
The majority of <strong>the</strong> waste which is not recycled is currently landfilled in landfill sites operated <strong>by</strong> private<br />
sec<strong>to</strong>r companies; however, <strong>the</strong> increases in landfill tax, particularly <strong>the</strong> announcement in <strong>the</strong> 2009<br />
budget that landfill tax will increase <strong>to</strong> £72 per <strong>to</strong>nne <strong>by</strong> 2013 will provide fur<strong>the</strong>r encouragement <strong>to</strong><br />
private sec<strong>to</strong>r companies which are currently developing options for treatment plants which will recover<br />
energy from this waste.<br />
4.2.4 Growth Rates and Future Arisings<br />
The two surveys of arisings of commercial and industrial waste were conducted <strong>by</strong> <strong>the</strong> Environment<br />
Agency in 1998/99 and 2002/03. Table 11 shows that although <strong>the</strong>re was little change in overall arisings,<br />
<strong>the</strong> arisings of commercial waste has increased whilst <strong>the</strong> arisings of industrial waste have decreased.<br />
This is due <strong>to</strong> a shift in employment away from manufacturing industry and <strong>to</strong>wards a service-based<br />
economy.<br />
The lack of yearly data on <strong>the</strong> arisings of commercial and industrial waste makes it difficult <strong>to</strong> predict<br />
future arisings using his<strong>to</strong>ric trends. One projection estimated an average annual growth rate of 2% per<br />
annum for both commercial and industrial waste in <strong>the</strong> South East from 2005 <strong>to</strong> 2020. 37 Ano<strong>the</strong>r<br />
projection has been calculated using <strong>the</strong> Regional Economy-Environment Input-Output (REEIO) model<br />
which was developed <strong>by</strong> Cambridge Econometrics for <strong>the</strong> Environment Agency and <strong>the</strong> Regional<br />
Development Agencies. The model integrates economic growth of 50 commercial and industrial sec<strong>to</strong>rs<br />
with a set of key environmental pressures that include waste arisings. After accounting for <strong>the</strong> impact of<br />
future increases in land tax, <strong>the</strong> model predicted that growth would be approximately 1.3% each year, and<br />
rise <strong>to</strong> 84.5 million <strong>to</strong>nnes <strong>by</strong> 2020, as shown in Table 13. 38 The reduction in <strong>the</strong> proportion of industrial<br />
waste predicted is due <strong>to</strong> both <strong>the</strong> decoupling measures aimed at industrial waste and <strong>the</strong> expected<br />
continued shift <strong>to</strong>wards a service based economy.<br />
Table 13 Predicting C&I Waste arisings with <strong>the</strong> REEIO Model<br />
Commercial and Industrial<br />
Waste<br />
Proportion of Commercial<br />
Waste<br />
Proportion of Industrial<br />
Waste<br />
2002/03<br />
67.5 million<br />
<strong>to</strong>nnes<br />
2019/20<br />
84.5 million<br />
<strong>to</strong>nnes<br />
% growth per<br />
annum<br />
1.3%<br />
42% 53% 2.5%<br />
58% 47% -2.5%<br />
Ano<strong>the</strong>r estimate of future arisings used information from four Regional Assembly Strategy <strong>report</strong>s (East<br />
Midlands, East of England, South East and North West which, between <strong>the</strong>m, are estimated <strong>to</strong> account<br />
37<br />
Model for future waste management capacity needs in <strong>the</strong> South East. Report <strong>by</strong> ERM for South East England Regional Assembly (SEERA),<br />
September 2005.<br />
38<br />
Partial Regula<strong>to</strong>ry Impact Assessment of <strong>the</strong> Review of England’s Waste Strategy. Defra, March 2006.
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for about 40% of overall arisings) <strong>to</strong> estimate that commercial and industrial waste arisings in <strong>the</strong> UK<br />
would increase from 83 million <strong>to</strong>nnes in 2001 <strong>to</strong> 94 million <strong>to</strong>nnes <strong>by</strong> 2020 (based on Environment<br />
Agency data for 1998/99). 39 This is equivalent <strong>to</strong> an average growth rate of 0.8% per annum for <strong>the</strong><br />
overall waste stream, which is lower than <strong>the</strong> estimated average growth rate of 1.4% determined using<br />
<strong>the</strong> REEIO model.<br />
It is likely that commercial and industrial waste arisings will grow at different rates, due <strong>to</strong> continuing shift<br />
<strong>to</strong>wards a service based economy and <strong>the</strong> waste minimisation activities and future increases in landfill<br />
tax. Based on <strong>the</strong> sources above, and industry expert opinion, <strong>the</strong> subsequent predictions used here<br />
have assumed an average growth rate of 1% per annum <strong>to</strong> estimate future arisings of commercial waste,<br />
and 0% per annum for industrial waste as it is unlikely <strong>the</strong>re will be any growth in <strong>the</strong> arisings of industrial<br />
waste.<br />
4.2.5 Conclusion<br />
Commercial and Industrial wastes arise from industry, trade or business activities. Although <strong>the</strong> contents<br />
are similar <strong>to</strong> MSW, <strong>the</strong> relative proportions of material content vary. Disposal of this waste stream is not<br />
<strong>the</strong> responsibility of <strong>the</strong> local authority, and consequently information on arisings and disposal is limited.<br />
However it is clear that this waste stream produces considerably more waste than MSW, <strong>to</strong>talling 82.6<br />
million <strong>to</strong>nnes in 2003.<br />
Information from <strong>the</strong> Environment Agency shows that most of this waste stream is disposed of <strong>to</strong> landfill,<br />
although a significant proportion, much larger than for MSW, is recycled.<br />
4.3 Construction and Demolition (C&D)<br />
4.3.1 Definition<br />
Construction and demolition waste arises largely from <strong>the</strong> demolition of buildings and structures, e.g.<br />
residential, commercial and transport systems.<br />
4.3.2 Composition<br />
Such waste usually contains a high proportion of minerals – demolished brick, concrete, cement and<br />
mortar. Minerals are not biodegradable or combustible. Two options exist for its disposal, removal <strong>to</strong><br />
landfill, or recycling <strong>to</strong> aggregate. A fur<strong>the</strong>r component is a proportion of wood waste, which is <strong>read</strong>ily<br />
combustible or biodegradable over time.<br />
Arisings of wood waste from this waste stream often go unrecorded as only material suitable for<br />
aggregate recycling is recorded. In addition <strong>the</strong> wood waste generated is almost invariably treated in<br />
some way, chemically or painted or o<strong>the</strong>rwise contaminated, which may be classified as hazardous under<br />
present legislation and may have <strong>to</strong> be dealt with in specially designated facilities. For more information<br />
on this subsection, please see <strong>the</strong> later section on wood waste.<br />
4.3.3 Current Arisings<br />
There is little data on <strong>the</strong> amount of C&D waste arisings. This will change in years <strong>to</strong> come as <strong>the</strong> PPC<br />
requirements mean that all sites will have <strong>to</strong> provide data on C&D waste inputs <strong>by</strong> 2012.<br />
39 Quantification of <strong>the</strong> Potential Energy from Residuals (EfR) in <strong>the</strong> UK. Report <strong>by</strong> Oakdene Hollins for The Institution of Civil Engineers and The<br />
Renewable Power Association, March 2005.<br />
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Table 14 shows <strong>the</strong> estimated arisings of C&D waste in <strong>the</strong> UK <strong>by</strong> English Region 40 and <strong>by</strong> Country. The<br />
waste will contain a mixture of mineral waste, soil, wood and plastics.<br />
Table 14 C&D Waste arisings in <strong>the</strong> UK, 2005<br />
Region Construction and<br />
Demolition Waste<br />
(‘000 <strong>to</strong>nnes)<br />
East Midlands 9,821<br />
East of England 11,553<br />
London 8,034<br />
North East 4,815<br />
North West 11,345<br />
South East 14,245<br />
South West 9,482<br />
West Midlands 9,840<br />
Yorkshire and Humber 10,497<br />
England - Total 89,632<br />
Nor<strong>the</strong>rn Ireland 12,200 41<br />
Scotland 11,800 42<br />
Wales 5,000 43<br />
UK – Total 118,600<br />
A breakdown of <strong>the</strong> disposal routes for C&D waste arisings is shown in Table 15. 40 As can be seen a<br />
significant proportion of <strong>the</strong> material is al<strong>read</strong>y recycled, almost all of this will be mineral waste that is<br />
crushed and used as aggregate, displacing virgin aggregate.<br />
Table 15 Regional arisings and management (‘000 <strong>to</strong>nnes) of C&D waste in England<br />
Region Recycled Used on Exempt<br />
Site<br />
Landfilled Total<br />
East Midlands 5,591 733 3,497 9,821<br />
East of England 6,031 1,683 3,839 11,553<br />
London 4,846 2,041 1,147 8,034<br />
North East 1,881 804 2,130 4,815<br />
North West 6,721 1,958 2,666 11,345<br />
South East 6,615 2,513 5,117 14,245<br />
South West 4,030 2,017 3,435 9,482<br />
West Midlands 4,918 2,911 2,011 9,840<br />
Yorkshire and Humber 5,806 7856 3,906 10,497<br />
England –Total 46,439 15,445 27,748 89,632<br />
Nor<strong>the</strong>rn Ireland - - - 12,200<br />
Scotland 50% 44 - - 11,800<br />
Wales 29% 56% 15% 5,000<br />
40 Survey of Arisings and Use of Alternatives <strong>to</strong> Primary Aggregates in England, 2005; Construction, Demolition and Excavation Waste. Report for<br />
Department for Communities and Local Government <strong>by</strong> Capita Symonds Ltd, in association with WRc plc, February 2008<br />
41 Survey on <strong>the</strong> arising and management of construction and demolition waste in Wales in 2005-06. Environment Agency, Wales.<br />
42 Waste Data Digest 8: Key facts and trends. Scottish Environmental Protection Agency, 2008<br />
43 Construction and demolition waste survey. Environment and Heritage Service (EHS), 2004<br />
44 Internal AEA estimate from AEA expert.
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4.3.4 Future Arisings<br />
Three surveys of arisings of construction and demolition (C&D) waste in England have been conducted<br />
since <strong>the</strong> year 2000. The findings are summarised in Table 16.<br />
Table 16: Estimated arisings (million <strong>to</strong>nnes) of construction and demolition waste in England<br />
2001 2003 2005<br />
Recycled aggregate and soil 43.3 45.4 46.4<br />
Landfilled at landfill sites 23.2 29.1 27.8<br />
Used at Registered Exempt sites 22.4 16.4 15.4<br />
Total 88.9 90.9 89.6<br />
A comparison of <strong>the</strong> estimates for 2001, 2003 and 2005 shows that <strong>the</strong> <strong>to</strong>tal arisings of C&D waste are<br />
similar. The amount of C&D waste which is recycled has increased from 49% in 2001 <strong>to</strong> 52% in 2005,<br />
but this increase is not statistically significant. The amount of material used on Registered Exempt sites<br />
has fallen <strong>by</strong> 7 million <strong>to</strong>nnes since 2001, and <strong>the</strong> amount of waste landfilled at landfill sites has increased<br />
<strong>by</strong> 4.5 million <strong>to</strong>nnes since 2001. 45<br />
The data in Table 16 show that <strong>the</strong>re has been little growth in C&D arisings since 2001. Ano<strong>the</strong>r<br />
projection estimated an average annual growth rate of 0% per annum for construction and demolition<br />
waste in <strong>the</strong> South East from 2005 <strong>to</strong> 2020. Consequently, an average growth rate of 0% per annum has<br />
been used <strong>to</strong> estimate future arisings of this stream.<br />
4.3.5 Conclusions<br />
Construction and demolition waste is <strong>the</strong> largest of <strong>the</strong> three controlled waste streams, with <strong>the</strong> UK<br />
producing an estimated 118.6 million <strong>to</strong>nnes in 2005.<br />
The majority of <strong>the</strong> waste is mineral, bricks, concrete, etc, and as such can be crushed and used <strong>to</strong><br />
displace virgin aggregate. A significant proportion will be soil, which can be reused as soil or also used <strong>to</strong><br />
displace virgin aggregate. However this waste stream will also contain a proportion of wood and plastics<br />
that could be used for energy production. Although it is possible <strong>to</strong> recycle or recover many of <strong>the</strong>se<br />
materials, in practice this is not often done due <strong>to</strong> <strong>the</strong> level of contamination and <strong>the</strong> diverse nature of <strong>the</strong><br />
sources.<br />
Data on arisings of this waste stream is currently very limited, however this situation should improve in <strong>the</strong><br />
near future with <strong>the</strong> <strong>report</strong>ing requirements of <strong>the</strong> PPC becoming widesp<strong>read</strong>.<br />
4.3.6 Predicted Future Arisings for MSW, C&I and C&D<br />
Table 17 gives <strong>the</strong> summary arisings of Municipal Solid Waste, Commercial and Industrial Waste and<br />
Construction and Demolition Wastes <strong>by</strong> country in <strong>the</strong> UK. For all countries in <strong>the</strong> UK significantly more<br />
construction and demolition waste is produced than any o<strong>the</strong>r waste stream, while MSW waste arisings is<br />
<strong>the</strong> smallest waste stream of <strong>the</strong> three controlled categories.<br />
45 Sites exempted under <strong>the</strong> terms of Paragraphs 9A(1) and/or 19A(2) of Schedule 3 <strong>to</strong> <strong>the</strong> Waste Management Licensing Regulations 1994 as<br />
amended <strong>by</strong> <strong>the</strong> Waste Management Licensing (England and Wales) (Amendment and Related Provisions) (No.3) Regulations 2005 (SI<br />
No.2005/1728); ‘Paragraph 9A(1) sites’ are registered exempt sites where exemption holders are permitted <strong>to</strong> sp<strong>read</strong> up <strong>to</strong> 20,000 m³/ha of certain<br />
specified waste materials including soil, rock, ash, some sludges, dredgings or C&D waste for land reclamation /res<strong>to</strong>ration / improvement purposes or<br />
agricultural improvement. Paragraph 19A(2) sites are registered exempt sites where exemption holders are permitted <strong>to</strong> use certain specified waste<br />
materials including C&D waste, excavation waste, ash, clinker, rock, wood or gypsum in connection with recreational or infrastructure projects,<br />
excluding land reclamation.<br />
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Table 17 Waste arisings (‘000,000 <strong>to</strong>nnes) in <strong>the</strong> UK<br />
Year England Wales Scotland 46 Nor<strong>the</strong>rn<br />
Ireland<br />
Total<br />
MSW 28.5 47 1.8 48 3.0 1.1 49 34.4<br />
C&I waste 67.9 50 5.3 51 7.8 1.6 52 82.6<br />
C&D waste 89.6 53 12.2 54 11.8 5.0 55 118.6<br />
Total 186.0 19.3 22.6 7.7 235.6<br />
Using <strong>the</strong> prediction figures discussed in preceding sections, Table 18 shows <strong>the</strong> estimated arisings of<br />
municipal solid waste, commercial waste, industrial waste and construction and demolition waste in 2010,<br />
2015 and 2020. These have been produced using <strong>the</strong> <strong>to</strong>nnage arisings shown in Table 18 (assuming a<br />
baseline year of 2005) and <strong>the</strong> average growth rates for each of <strong>the</strong>se waste streams determined in this<br />
section of <strong>the</strong> <strong>report</strong>: MSW growth at 0.75%, Commercial waste at 1%, Industrial waste at 0% and C&I<br />
waste at 0%. The <strong>to</strong>tal arisings of <strong>the</strong>se waste streams in <strong>the</strong> UK is estimated <strong>to</strong> rise from 236 million<br />
<strong>to</strong>nnes in 2005 <strong>to</strong> 246 million <strong>to</strong>nnes in 2020 due <strong>to</strong> <strong>the</strong> growth in <strong>the</strong> arisings of both municipal solid<br />
waste and commercial waste.<br />
Table 18: Estimated future UK waste arisings (‘000,000 <strong>to</strong>nnes)<br />
Year<br />
2005 2010 2015 2020<br />
Municipal Solid Waste 34 36 37 38<br />
Commercial Waste 37 39 41 43<br />
Industrial Waste 45 45 45 45<br />
Construction and Demolition Waste 119 119 119 119<br />
Total 236 239 242 246<br />
The projections of future arisings shown in Table 18 have not considered <strong>the</strong> potential impacts <strong>the</strong> current<br />
economic situation may have on future waste arisings. The arisings of some waste streams could reduce<br />
over <strong>the</strong> next few years due <strong>to</strong> <strong>the</strong> following fac<strong>to</strong>rs:<br />
• Municipal solid waste - Reduction in MSW growth rate due <strong>to</strong> fewer houses being built,<br />
<strong>to</strong>ge<strong>the</strong>r with continuing waste reduction activities and less spending per household<br />
• Commercial waste - Reduction in C&I growth rate, and this could become negative as <strong>the</strong><br />
number of commercial businesses reduces (<strong>the</strong> financial situation is anticipated <strong>to</strong> have more<br />
impact on <strong>the</strong> commercial sec<strong>to</strong>r than <strong>the</strong> industrial sec<strong>to</strong>r due <strong>to</strong> <strong>the</strong> reduction in <strong>the</strong> number<br />
of jobs in <strong>the</strong> retail and banking sec<strong>to</strong>rs).<br />
• Construction and demolition waste – reduction in number of buildings being demolished <strong>to</strong><br />
start new construction/development projects.<br />
Waste arisings for all of <strong>the</strong>se streams could fall over <strong>the</strong> next few years, but should begin <strong>to</strong> increase<br />
again as economic recovery occurs.<br />
46<br />
Waste Data Digest 8: Key facts and trends. Scottish Environmental Protection Agency, 2008<br />
47<br />
Defra - http://www.defra.gov.uk/environment/statistics/wastats/bulletin08.htm<br />
48<br />
Municipal Waste Management Report for Wales, 2007-08. Statistics for Wales, Oc<strong>to</strong>ber 2008<br />
49<br />
Municipal Waste Management Nor<strong>the</strong>rn Ireland 2005/06 Summary Report, December 2006<br />
50<br />
Environment Agency 2006 – Strategic Waste Management Assessment 2002/03<br />
51<br />
Environment Agency Wales, http://www.environment-agency.gov.uk/aboutus/organisation/35675.aspx<br />
52<br />
Commercial & Industrial Waste Arisings Survey 2004/05. Environment & Heritage Service, March 2007<br />
53<br />
Survey of Arisings and Use of Alternatives <strong>to</strong> Primary Aggregates in England, 2005; Construction, Demolition and Excavation Waste. Report for<br />
Department for Communities and Local Government <strong>by</strong> Capita Symonds Ltd, in association with WRc plc, February 2008<br />
54<br />
Survey on <strong>the</strong> arising and management of construction and demolition waste in<br />
Wales in 2005-06. Environment agency Wales<br />
55<br />
Construction and demolition waste survey. Environment and Heritage Service (EHS), 2004
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4.4 Bio-solids<br />
4.4.1 Definition<br />
Sewage is <strong>the</strong> wastewater collected from homes, industrial premises, offices and commercial premises<br />
and carried through <strong>the</strong> sewerage system <strong>to</strong> a wastewater treatment works. The residual component,<br />
once <strong>the</strong> clean water has been discharged back in<strong>to</strong> waterways, is <strong>the</strong> bio-solids, (also known as sewage<br />
sludge).<br />
4.4.2 Composition<br />
Sewage is mostly water, including drainage waster from car parks, roads and o<strong>the</strong>r areas of concrete or<br />
tarmac. Sewage contains about 3% solid waste, which reduces <strong>to</strong> under 1% once it has been screened<br />
(i.e. all <strong>the</strong> grit, fats, soil, sanitary and contraceptive waste are removed) at <strong>the</strong> sewage treatment works.<br />
Human waste forms a relatively small proportion of <strong>the</strong> <strong>to</strong>tal volume of sewage. 56<br />
Sewage goes through several treatment processes at a waste-water works before it is returned <strong>to</strong> river or<br />
<strong>the</strong> sea in a condition such that no significant pollution or environmental degradation occurs. The main<br />
<strong>by</strong>-product of any sewage treatment works is bio-solids.<br />
The treatment and disposal of bio-solids is subject <strong>to</strong> various regulations. The two most relevant pieces<br />
are <strong>the</strong> Urban Waste Water Treatment Directive (UWWT Directive), and <strong>the</strong> Sludge (use in agriculture)<br />
Regulations 1989. The Directive details controls for <strong>the</strong> treatment and disposal of bio-solids, and was <strong>the</strong><br />
legislation that banned disposal at sea, <strong>the</strong> option that was widely practiced, before 1998. The Sludge<br />
Regulations control <strong>the</strong> sp<strong>read</strong>ing of this material on land. In addition <strong>the</strong>re is <strong>the</strong> Safe Sludge Matrix<br />
from 2001, a voluntary agreement that ensures bio-solids is applied only <strong>to</strong> certain crops and plants. 57<br />
Sludge from secondary treatment and Anaerobic Digestion (AD) is still very high in water content (>90%<br />
in most cases) and is <strong>the</strong>refore often subjected <strong>to</strong> fur<strong>the</strong>r dewatering before final disposal. The<br />
dewatering decreases <strong>the</strong> volume of sludge and hence <strong>the</strong> cost of transport considerably. Such<br />
processes include centrifugation (which can increase <strong>the</strong> solid content <strong>to</strong> 24-30%, producing a sludge<br />
cake); belt/filter pressing (which can decrease <strong>the</strong> volume <strong>to</strong> 10-20% of <strong>the</strong> un-pressed sludge); and<br />
<strong>the</strong>rmal drying (which increases <strong>the</strong> sludge solids <strong>to</strong> 80-95% and results in sludge in <strong>the</strong> form of dust or<br />
pellets). These processes are used in particular in larger sewage treatment works where <strong>the</strong> cost of<br />
disposing of large volumes of high liquid content sludge is prohibitive.<br />
4.4.3 Current Arisings<br />
Information on <strong>the</strong> quantity of UK bio-solids arising, and <strong>the</strong> methods of disposal are release <strong>by</strong> Defra, up<br />
<strong>to</strong> 2005. 58 Since 1989/90 <strong>the</strong> level of arisings has increased <strong>to</strong> 1.4 million <strong>to</strong>nnes as a result of <strong>the</strong><br />
UWWT Directive and hence wastewater requiring more treatment. 59<br />
The UK produces some 11 billion litres of waste water every day, which goes <strong>to</strong> around 9,000 sewage<br />
treatment works around <strong>the</strong> country before <strong>the</strong> treated effluent is discharged <strong>to</strong> inland waters, estuaries<br />
and <strong>the</strong> sea. 56<br />
56<br />
Sewage Treatment in <strong>the</strong> UK, Defra 2002, http://www.defra.gov.uk/environment/water/quality/uwwtd/<strong>report</strong>02/pdf/uwwt<strong>report</strong>2.pdf<br />
57<br />
Sewage Sludge, Defra, http://www.defra.gov.uk/environment/statistics/waste/wrsewage.htm<br />
58<br />
e-Digest Statistics, Defra<br />
59<br />
Council Directive 91/271/EEC Urban Waste Water Treatment, 1991, http://eur-lex.europa.eu/LexUriServ/site/en/consleg/1991/L/01991L0271-<br />
20031120-en.pdf<br />
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Table 19 Bio-solids Arising in <strong>the</strong> UK (‘000 dry <strong>to</strong>nnes) 57<br />
Region 2000 2001 2002 2003 2004 2005<br />
England and Wales 941 1137 1249 1280 1221 1369<br />
Scotland 97 N/A 113 113 113 140<br />
Nor<strong>the</strong>rn Ireland 34 N/A 28 29 34 -<br />
Total 1,072 - 1,390 1,422 1,368 -<br />
Table 20 shows <strong>the</strong> sewage waste arising <strong>by</strong> UK region in dry weight. 60 The bio-solids arising <strong>by</strong> English<br />
region is difficult <strong>to</strong> calculate since <strong>the</strong> water companies who produce it operate across regions that do<br />
not correspond <strong>to</strong> <strong>the</strong> divisions of <strong>the</strong> development agencies in England. Therefore <strong>the</strong> bio-solid arisings<br />
have been <strong>report</strong>ed according <strong>to</strong> <strong>the</strong> water company regions.<br />
Table 20 Estimated bio-solids arising <strong>by</strong> English and Welsh water companies in 2000 61<br />
Region Dry Solids<br />
(‘000 <strong>to</strong>nnes)<br />
United Utilities Water 258<br />
Welsh Water 86<br />
Yorkshire Water 154<br />
Anglican Water 180<br />
Wessex Water 82<br />
Southwest Water 56<br />
Northumbria Water 65<br />
Severn Trent Water 262<br />
Thames Water 325<br />
Sou<strong>the</strong>rn Water 136<br />
Total 1,605<br />
60 Most figures relating <strong>to</strong> sewage sludge (biosolids) are quoted in terms of dry solids. This is due <strong>to</strong> <strong>the</strong> variable water contents of <strong>the</strong> sludges.<br />
Quoting data as dry solids allows comparison between sludges. However, it must be remembered that water is always present in biosolids or sewage<br />
sludge. If sewage sludge is 10% dry solids, 90% of <strong>the</strong> volume will be water and this will also represent a considerable weight.<br />
61 Ofwat 2004, Utilities Summary of Outputs, http://www.ofwat.gov.uk
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Figure 8 Geographical representation of <strong>the</strong> operating areas of <strong>the</strong> water companies in England and Wales. 62<br />
Ano<strong>the</strong>r source of information are <strong>the</strong> individual water companies, but <strong>the</strong> level of information <strong>report</strong>ed<br />
varies company <strong>by</strong> company.<br />
4.4.4 Current Disposal Options<br />
There are a number of options available for <strong>the</strong> disposal of bio-solids, each of which are used <strong>to</strong> a varying<br />
degree, as illustrated in Figure 9. Although bio-solids are predominantly disposed of <strong>to</strong> land currently,<br />
this situation may change as discussed below.<br />
Application <strong>to</strong> land<br />
Bio-solids are predominately recycled <strong>to</strong> land, acting as a fertiliser. 63 This is a flexible solution for <strong>the</strong><br />
wastewater opera<strong>to</strong>rs as agricultural sites can be changed or sourced relatively quickly in order <strong>to</strong> meet<br />
changing operational needs.<br />
Application of bio-solids <strong>to</strong> land that is being reclaimed is also practiced, as it can help <strong>to</strong> res<strong>to</strong>re soil<br />
nutrients and stability. Bio-solids can be incorporated in<strong>to</strong> spoil <strong>to</strong> increase <strong>the</strong> stability, creating a soil<br />
64,65, 66<br />
that contains nutrients enough <strong>to</strong> support plant growth.<br />
62 Con29DW, Drainage and Water Enquiry, http://www.drainageandwater.co.uk<br />
63 Thames Water 25 year Sludge Strategy, 2008, http://www.thameswater.co.uk/cps/rde/xbcr/SID-54091C65-CAD380F4/corp/sludge-strategy.pdf<br />
64 The Beneficial Use of Sewage Sludge in Land Reclamation, 2004, Water UK,<br />
http://www.water.org.uk/static/files_archive/2Sludge_for_Land_res<strong>to</strong>ration_briefing_Notes_v2_march_15.doc<br />
65 Beneficial Effects of Biosolids on Soil Quality and Fertility ADAS Research review 2001-2002 – Environment ADAS Ltd. www.adas.co.uk<br />
66 Wastewater treatment and use in agriculture - FAO irrigation and drainage paper 47 M.B. Pescod 1992<br />
Food and Agriculture Organisation of <strong>the</strong> United Nations www.fao.org/<br />
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However disposal <strong>to</strong> land may reduce in coming years as legislative and practical constraints limit this<br />
route. 67 The available land bank may reduce due <strong>to</strong> a reluctance <strong>to</strong> have food products grown on land<br />
treated with this waste, although <strong>the</strong> growth of energy crops would provide a (small) mitigating land<br />
availability. 67 The impact of <strong>the</strong> Nitrates Directive (Nitrate Vulnerable Zones Regulations) may be a<br />
reduction in <strong>the</strong> volume of sludge that can be applied in certain areas.<br />
Landfill<br />
A small amount of sludge is disposed of <strong>to</strong> landfill, which is largely used only as a fall back option as it<br />
can be used at very short notice. 56 This route is not sustainable in <strong>the</strong> longer term and <strong>the</strong> costs<br />
associated with it are increasing as landfill tax levels go up and void space is reduced. In addition, due <strong>to</strong><br />
<strong>the</strong> high water content of bio-solids only a limited number of sites are willing <strong>to</strong> accept it due <strong>to</strong> <strong>the</strong><br />
potential impact on <strong>the</strong> landfill sites’ leachate management programme.<br />
Incineration<br />
Incineration is <strong>the</strong> second largest disposal route, generally used <strong>by</strong> <strong>the</strong> larger treatment works. 56 The<br />
heat generated is often used on site <strong>to</strong> meet <strong>the</strong> heating needs of <strong>the</strong> process, i.e. <strong>to</strong> dry <strong>the</strong> bio-solids,<br />
and generate electricity. Several stages of cleaning of <strong>the</strong> flue gases are incorporated within <strong>the</strong> process<br />
<strong>to</strong> ensure <strong>the</strong>y meet EU emission limits set <strong>by</strong> <strong>the</strong> Waste Incineration, <strong>the</strong> Integrated Pollution Prevention<br />
and Control (IPPC) and <strong>the</strong> Landfill Directives. 68 The calorific value of bio-solids is dependent on <strong>the</strong> type<br />
of material, its water content (<strong>the</strong> degree of dewatering) and <strong>the</strong> concentration of organic matter present,<br />
solids content, calorific values and biomass contents vary according <strong>to</strong> <strong>the</strong> type of treatment.<br />
Incineration is a relatively expensive option, so it is only of interest in areas where alternative disposal<br />
methods are not available or <strong>the</strong> cost of transportation is prohibitive.<br />
Incineration of bio-solids involves burning <strong>the</strong> sludge at 600-900°C <strong>to</strong> destroy <strong>the</strong> organic content, leaving<br />
a residue of mineral ash for final disposal (usually <strong>to</strong> landfill or controlled waste re-use such as land<br />
reclamation). The net calorific value of dried bio-solids, i.e. its energy content after deducting <strong>the</strong> heat<br />
required <strong>to</strong> evaporate <strong>the</strong> remaining water is around 23MJ/kg of volatile solids. 69<br />
Co-incineration<br />
The bio-solids, ei<strong>the</strong>r as dewatered cake, but generally as dried pellets, can be burnt in adapted (WID<br />
compliant) plants, often co-fired with coal. It is possible <strong>to</strong> burn bio-solids with municipal waste, however,<br />
<strong>the</strong> burner design system must be capable of handling both fuels.<br />
67 Thames Water 25 year Sludge Strategy, 2008, http://www.thameswater.co.uk/cps/rde/xbcr/SID-54091C65-CAD380F4/corp/sludge-strategy.pdf<br />
68 Waste Incineration Directive http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=OJ:L:2000:332:0091:0111:EN:PDF, Integrated Pollution<br />
Prevention and Control, original legislation, http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=CELEX:31996L0061:EN:HTML, Landfill Directive<br />
http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=OJ:L:1999:182:0001:0019:EN:PDF<br />
69 Sewage Sludge Disposal: operational and environmental issues, Bruce A.M. and Evans, T.D., Foundation of Water Research, 2002.
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20%<br />
1%<br />
11%<br />
4.4.5 Future Arisings<br />
4%<br />
64%<br />
Farmland<br />
Landfill<br />
Incineration<br />
Land reclamation/res<strong>to</strong>ration<br />
O<strong>the</strong>r<br />
Figure 9 Disposal of bio-solids in 2004 70<br />
The volumes of bio-solids created are increasing, through increased population, and through increased<br />
levels of treatment of municipal sewage, and at times dedicated industrial effluent treatment plants run <strong>by</strong><br />
<strong>the</strong> water companies. The increase is also in part due <strong>to</strong> <strong>the</strong> increased levels of sewage treatment<br />
required through tightened Regulations. 71<br />
In 2004-5 1.72 Mt of dry bio-solids were produced. Work carried out internally in AEA has estimated that<br />
this will increase <strong>to</strong> 2.5 Mt <strong>by</strong> 2030 due <strong>to</strong> changes in industry practice brought about <strong>by</strong> legislation<br />
relating <strong>to</strong> requirements for improved treatment practices.<br />
One water company, Thames Water, have estimated <strong>the</strong> future arising of bio-solids until 2021, and<br />
extrapolated fur<strong>the</strong>r <strong>to</strong> 2035. 72 The prediction is for a steady increase in <strong>the</strong>ir production of bio-solids year<br />
on year.<br />
The volume of bio-solids available for conversion in<strong>to</strong> fuels and energy is likely <strong>to</strong> increase in future years,<br />
due <strong>to</strong> increasing populations in some areas, and decreasing opportunities <strong>to</strong> utilise traditional disposal<br />
methods in all areas of <strong>the</strong> UK.<br />
70<br />
Sewage sludge arisings and management 1986/97 – 2005, Defra.<br />
71 th<br />
Determining sludge production from wastewater treatment, Clode, K., Khraisheh, M., Ballinger, D., 2008, 13 European Biosolids and Organic<br />
Resources Conference and Workshop.<br />
72<br />
Thames Water 25 year Sludge Strategy, 2008, http://www.thameswater.co.uk/cps/rde/xbcr/SID-54091C65-CAD380F4/corp/sludge-strategy.pdf,<br />
based on Local Authority growth projections, taking in consideration such variables as new development and housing density until 2021, and <strong>the</strong>n<br />
linearly extrapolated <strong>to</strong> provide best future estimates <strong>to</strong> 2035, with no specific allowance been made for additional sludge arising from currently<br />
unknown changes in legislation treatment standards, cus<strong>to</strong>mer behaviour or o<strong>the</strong>r fac<strong>to</strong>rs, such as impact of Local Authority waste strategies.<br />
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4.4.6 Conclusions<br />
Bio-solids are <strong>the</strong> product of <strong>the</strong> waste-water treatment works. Even after several stages of treatment it is<br />
still largely comprised of water.<br />
Increasing waste-water legislation, and increasing population in <strong>the</strong> UK, results in increased volumes of<br />
bio-solids: up <strong>to</strong> 1,368,000 dry <strong>to</strong>nnes in 2004. Much of this waste is ultimately recycled <strong>to</strong> land as a<br />
fertiliser but this use will be restricted in <strong>the</strong> future due <strong>to</strong> tighter regulation of nitrogen application <strong>to</strong><br />
agricultural land in some sensitive areas.<br />
4.5 Agricultural Residues and Waste<br />
4.5.1 Definition<br />
Agriculture produces a variety of residues, but only limited waste. The distinction is made between<br />
controlled wastes and uncontrolled resides. Wastes are items such as chemicals, plastic, containers and<br />
o<strong>the</strong>r packaging, and controls on this waste stream were introduced in May 2006. Agricultural waste is<br />
<strong>to</strong>o heterogeneous and widely dispersed <strong>to</strong> provide an easy feeds<strong>to</strong>ck. Agricultural residues include<br />
animal manures and slurry, and crop straws and husks, which rarely leave <strong>the</strong> confines of a farm, and<br />
<strong>the</strong>refore are not recorded. Such residues are generally homogeneous which makes <strong>the</strong>m a more<br />
realistic potential feeds<strong>to</strong>ck. Manure and slurry sp<strong>read</strong> at <strong>the</strong> place of production, for <strong>the</strong> benefit of<br />
agriculture, is not considered <strong>to</strong> be waste under <strong>the</strong> current regulations. In 2005 <strong>the</strong> European<br />
Commission judged that lives<strong>to</strong>ck effluent would fall outside <strong>the</strong> classification of waste if it were<br />
subsequently used as a soil fertiliser. 73 The application of <strong>the</strong>se residues <strong>to</strong> land is a traditional practice<br />
that helps <strong>to</strong> replenish nutrients, and reduces <strong>the</strong> amount of artificial fertiliser that would o<strong>the</strong>rwise be<br />
applied.<br />
However, agricultural residues can lead <strong>to</strong> air, land and water pollution if not managed properly. Farm<br />
slurries are many times more polluting than human sewage and when not correctly managed can cause<br />
serious environmental damage, particularly <strong>by</strong> adulterating watercourses and producing odours. Heavy<br />
fines can be imposed on farmers for pollution of watercourses with animal slurries. In addition traditional<br />
disposal methods are increasingly leading <strong>to</strong> problems. Defra now advise against general sp<strong>read</strong>ing of<br />
slurry for example, due <strong>to</strong> concerns about <strong>the</strong> loss of ammonia <strong>to</strong> <strong>the</strong> air. Such concerns are a major<br />
driver <strong>to</strong> re-evaluate <strong>the</strong> methods for treating and disposing of farm wastes and residues.<br />
4.5.2 Composition<br />
Agricultural residues can be subdivided in<strong>to</strong> two categories:<br />
• Wet residues are animal slurries and farmyard manures that have a solid content of under 15%.<br />
• Dry residues include straw, husks and processing waste, as well as poultry litter from poultry<br />
reared for meat.<br />
73 European Court judgment, Case C-416/02 European Commission v Kingdom of Spain,<br />
http://europa.eu.int/smartapi/cgi/sga_doc?smartapi!celexplus!prod!CELEXnumdoc&lg=en&numdoc=62002J0416.
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Wet Agricultural Residues<br />
Wet farm residues are characterised <strong>by</strong> <strong>the</strong> lives<strong>to</strong>ck and waste reception and collection methods, which<br />
are largely consistent throughout <strong>the</strong> UK.<br />
Farm slurries are derived from three major sources: cattle, pigs and egg-laying poultry. In addition <strong>to</strong><br />
animal effluent, o<strong>the</strong>r sources of wet farm residues include parlour/dairy/vegetable washings, waste milk,<br />
bio-solids and silage effluent. Currently <strong>the</strong> majority of <strong>the</strong>se residues are recycled <strong>to</strong> land.<br />
Slurry accumulates and must be managed wherever animals are housed, a particular issue during <strong>the</strong><br />
over wintering of animals indoors, or in milking parlours and egg production facilities. Slurry handling<br />
systems usually consist of floor scrapers <strong>to</strong> move <strong>the</strong> slurry in<strong>to</strong> channels from which it is pumped in<strong>to</strong> a<br />
s<strong>to</strong>rage tank or lagoon. Sophisticated systems also use a separa<strong>to</strong>r <strong>to</strong> remove <strong>the</strong> fibrous portion of <strong>the</strong><br />
slurry for sale as a compost base, while <strong>the</strong> more basic systems allow natural settlement. The type of<br />
system used is relevant because it can dramatically affect <strong>the</strong> level of solids collected.<br />
Lives<strong>to</strong>ck Numbers and Residue Arisings<br />
The key aspect <strong>to</strong> utilising lives<strong>to</strong>ck slurry and manures is that <strong>the</strong>y must be collectable, and in practice<br />
this limits <strong>the</strong> utilisation of <strong>the</strong> residue <strong>to</strong> when <strong>the</strong> animals are housed. When <strong>the</strong> animals are on pasture<br />
fields, especially during <strong>the</strong> summer months, <strong>the</strong> manure is dropped on<strong>to</strong> <strong>the</strong> field and is unavailable for<br />
collection. In addition <strong>the</strong> type of bedding material used will affect <strong>the</strong> characteristics of <strong>the</strong> manure or<br />
slurry produced. Common bedding materials include straw, wood chips, sand, or compost. 74<br />
Fur<strong>the</strong>r, <strong>the</strong> collectable proportion of wet residues is al<strong>read</strong>y widely used as a fertiliser, as discussed<br />
above, and so availability is also an issue.<br />
The UK estimates of lives<strong>to</strong>ck residues vary considerably, as <strong>the</strong>se residues are rarely collected or<br />
regulated for disposal <strong>by</strong> third parties. They are estimated from <strong>the</strong> number and distribution of lives<strong>to</strong>ck,<br />
and <strong>the</strong>se will change as lives<strong>to</strong>ck farming changes each year. The most recent Environment Agency<br />
figure for agricultural wet waste was 45 million <strong>to</strong>nnes, while work performed <strong>by</strong> AEA generated <strong>the</strong><br />
considerably higher figure of 67-88 million <strong>to</strong>nnes produced annually.<br />
The diagram below illustrates <strong>the</strong> quantity and type of residues from typical UK lives<strong>to</strong>ck, and <strong>the</strong><br />
proportion each produces of slurry and farmyard manure (FYM).<br />
Quantity ('000 te)<br />
40000<br />
35000<br />
30000<br />
25000<br />
20000<br />
15000<br />
10000<br />
5000<br />
0<br />
15,124<br />
18,142<br />
34,423<br />
4,481<br />
4,901<br />
2,467<br />
FYM<br />
Slurry<br />
4,276 4,036<br />
Dairy Beef Pigs Poultry Sheep<br />
Figure 10 Slurry and FYM in UK, <strong>by</strong> main lives<strong>to</strong>ck categories<br />
74 Dairy Waste Anaerobic Digestion Handbook, <strong>by</strong> Dennis A. Burke P.E., June 2001 http://www.mrec.org/pubs/Dairy%20Waste%20Handbook.pdf<br />
UK<br />
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Although <strong>the</strong>re is considerable variation in <strong>the</strong> residue output of lives<strong>to</strong>ck, as it is species dependent, age<br />
and type of animal dependent, and residue collection system dependent, some generalisations can be<br />
made:<br />
• Where cows are housed, usually for part of <strong>the</strong> winter, and for regular portions of each day if it is<br />
a dairy herd, <strong>the</strong> slurry is usually collected mixed with straw, using a scraper system. Slurry is<br />
collected on around 18% of beef cattle farms, and 66% of dairy cattle farms. The addition of<br />
straw will alter <strong>the</strong> <strong>to</strong>tal solid composition, as will <strong>the</strong> type of housing system in use. Rinsing of<br />
<strong>the</strong> area is not common, so dilution of <strong>the</strong> slurry with water is minimal. 75<br />
• Most pigs are housed for <strong>the</strong> majority of <strong>the</strong>ir lives, often 100%, making collection of <strong>the</strong>ir<br />
residues viable. However variation in <strong>the</strong> types of housing, and methods of farming mean that<br />
<strong>the</strong>re are large variations of <strong>to</strong>tal solids and organic dry matter. Larger pig farms usually collect<br />
<strong>the</strong> waste as a liquid slurry, at a high dilution. O<strong>the</strong>r methods include <strong>the</strong> use of a scraper system<br />
which produces a higher dry content. 75<br />
• Egg laying poultry do not use bedding, and <strong>the</strong>refore <strong>the</strong>ir residues are quite wet and count as<br />
wet residue. In contract poultry raised for meat will use bedding, often sawdust and wood<br />
shavings, and considerable time elapses before <strong>the</strong> residue is collected, permitting significant<br />
drying <strong>to</strong> occur. Thus <strong>the</strong>se residues are considered <strong>to</strong> be dry residues.<br />
• Sheep are largely un-housed, so it is not possible <strong>to</strong> collect <strong>the</strong>ir residues. For this reason <strong>the</strong>y<br />
have not been considered any fur<strong>the</strong>r in this <strong>report</strong>.<br />
Lives<strong>to</strong>ck can be grouped according <strong>to</strong> <strong>the</strong> category of animal and <strong>the</strong> type of collection system that is<br />
likely <strong>to</strong> be used. Such a scaling system has been used previously <strong>to</strong> estimate <strong>the</strong> potential methane<br />
yield of agricultural residues for Defra. 76 These scaling fac<strong>to</strong>rs can be applied <strong>to</strong> <strong>the</strong> <strong>to</strong>tal number of<br />
lives<strong>to</strong>ck, <strong>to</strong> begin <strong>to</strong> estimate <strong>the</strong> regional arisings of residues.<br />
The <strong>to</strong>tal current lives<strong>to</strong>ck numbers are detailed in Table 21, and have been taken from <strong>the</strong> Farm Surveys<br />
of England, Scotland, Wales and Nor<strong>the</strong>rn Ireland. Fur<strong>the</strong>r breakdown of <strong>the</strong> numbers can be found in<br />
Appendix 1, where more detailed categorisation has been used. 77<br />
Table 21 Lives<strong>to</strong>ck numbers for <strong>the</strong> UK, on a regional basis.<br />
Cattle Pigs Total Fowls<br />
Region<br />
(‘000 head) (‘000 head) (‘000 head)<br />
East Midlands 519 418 24,178<br />
East of England 220 1,066 25,312<br />
North East 286 85 2,428<br />
North West 965 160 8,263<br />
South East inc. London 461 259 9,867<br />
South West 1,804 480 18,316<br />
West Midlands 760 235 16,602<br />
Yorkshire and Humber 583 1,239 14,408<br />
England - Total 5,598 3,943 119,374<br />
Nor<strong>the</strong>rn Ireland 1,623 402 16,322<br />
Scotland 1,897 457 8,308<br />
Wales 1,323 25 5,836<br />
UK - Total 10,440 4,828 150, 000<br />
75 Feeds<strong>to</strong>cks for Anaerobic Digestion, AD-NETT Report 2000.<br />
76 Assessment of Methane Management and Recovery Options for Lives<strong>to</strong>ck Manures and Slurries, 2005, AEA for Defra. Figures calculated from<br />
English data. Applied uniformly here <strong>to</strong> England, Scotland, Wales and Nor<strong>the</strong>rn Ireland.<br />
77 June Survey of Agriculture and Horticulture (Land use, lives<strong>to</strong>ck and labour on agricultural holdings at 1 June 2008) England – Final Results, Defra,<br />
Published 20 November 2008. Welsh Agricultural Statistics 2007, http://wales.gov.uk/<strong>to</strong>pics/statistics/publications/was2007/?lang=en, 2008 June<br />
Agricultural and Horticultural Census for Scotland, http://www.scotland.gov.uk/Publications/2008/06/19154131/1 , The Agricultural Census in Nor<strong>the</strong>rn<br />
Ireland, 2008 http://www.dardni.gov.uk/da1_09_25820__08.09.160_agricultural_census_in_ni_-_results_for_june_2008_amended.pdf.pdf
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Lives<strong>to</strong>ck manure is principally composed of organic matter that if s<strong>to</strong>red in an anaerobic environment will<br />
decompose <strong>to</strong> produce methane. The level of methane production depends on <strong>the</strong> quantity and quality of<br />
<strong>the</strong> manure, and on <strong>the</strong> environment, i.e. <strong>the</strong> proportion that decomposes anaerobically.<br />
Table 22 details <strong>the</strong> manure generation characteristics of <strong>the</strong> various categories of lives<strong>to</strong>ck as discussed<br />
above. The amount of Volatile Solids is closely related <strong>to</strong> <strong>the</strong> quantity of dry matter produced in <strong>the</strong><br />
manure.<br />
Table 22 Animal manure generation characteristics 76<br />
Animal Proportion of <strong>the</strong><br />
year housed<br />
Proportion of<br />
waste collected<br />
as slurry<br />
Volatile Solids<br />
kg/head/day<br />
Dairy cow 59% 66% 3.48<br />
O<strong>the</strong>r cattle<br />
(excl. calves)<br />
50% 18% 2.7<br />
Calves 45% 0% 1.46<br />
Dry sow 100% 35% 0.63<br />
Sows plus litters 100% 75% 0.63<br />
Fattening pig<br />
(20 – 130kg)<br />
90% 33% 0.49<br />
Weaners<br />
(
54<br />
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Currently <strong>the</strong> majority of <strong>the</strong>se residues are recycled <strong>to</strong> agricultural land. The high water content makes<br />
large scale transportation unfeasible, and so utilisation for energy or fuel generation would likely be at a<br />
local scale.<br />
Dry Agricultural Residues<br />
There has been much interest in <strong>the</strong> use of dry agricultural residues for energy for some time. The UK<br />
Government (<strong>the</strong>n Department of Energy) supported a significant programme in <strong>the</strong> 1980s-early 1990s <strong>to</strong><br />
examine <strong>the</strong> potential and support demonstration projects. Two main dry agricultural residues were<br />
identified as: poultry litter and straw.<br />
Straw<br />
Straw is available from cereal and o<strong>the</strong>r 'combinable' crops such as oil seeds. The recent <strong>report</strong> <strong>by</strong> CSL<br />
for NNFCC gives a broad description of <strong>the</strong> straw market. 78 It is produced seasonally and is localised <strong>to</strong><br />
arable farming areas. Straw is produced during crop harvest and often remains on <strong>the</strong> ground after <strong>the</strong><br />
passage of stage one collection – <strong>the</strong> seed crop. It must <strong>the</strong>n be collected and baled in a second<br />
handling stage. For an estimation of regional crop area potentially generating straw, <strong>by</strong> crop type and<br />
region of <strong>the</strong> UK please see Appendix 1.<br />
The three main types of straw that are available in <strong>the</strong> UK are barley, wheat and oil seed rape (OSR). It<br />
is common for barley and oat straw <strong>to</strong> be consumed almost entirely <strong>by</strong> <strong>the</strong> lives<strong>to</strong>ck industry as part of <strong>the</strong><br />
winter diet with additional straw used for bedding, so this must be borne in mind when considering <strong>the</strong><br />
following figures. Cereal straw is also used <strong>to</strong> protect some crops, such as carrots, against frost and <strong>to</strong><br />
keep o<strong>the</strong>rs, such as strawberries, off <strong>the</strong> ground. OSR straw is not suitable for ei<strong>the</strong>r of <strong>the</strong>se uses.<br />
O<strong>the</strong>r potential industrial uses for straw are for paper-making, or in <strong>the</strong> production of industrial fibre,<br />
including constructional board manufacture. 79 Straw can also be used as a feeds<strong>to</strong>ck for power<br />
generation, as is <strong>the</strong> case at <strong>the</strong> EPRL Power station in Ely (see later chapter). OSR straw is popular for<br />
combustion, as it burns fiercely due <strong>to</strong> <strong>the</strong> presence of residual oilseeds. To moderate this, such straw is<br />
mixed with cereal straws <strong>to</strong> contain this volatility at lower levels.<br />
To prevent deterioration during s<strong>to</strong>rage, crops are generally harvested dry, i.e. moisture content below<br />
15% and, as straw is usually harvested immediately after harvesting <strong>the</strong> associated cereal or oilseed<br />
crop, its moisture content will be around <strong>the</strong> same. During poor wea<strong>the</strong>r, however, <strong>the</strong> crops may be<br />
harvested at higher moisture contents, meaning <strong>the</strong> straw will be wetter, or <strong>the</strong> straw may spoil in <strong>the</strong><br />
field, reducing that year’s yield.<br />
Straw is harvested over a short period (typically around 70 days), and for <strong>the</strong> remainder of <strong>the</strong> year<br />
s<strong>to</strong>rage is required. This s<strong>to</strong>rage may be done in Dutch barns or in stacks on <strong>the</strong> field. There will usually<br />
be some losses in dry matter during s<strong>to</strong>rage, mainly due <strong>to</strong> degradation of biomass. This loss is<br />
estimated <strong>to</strong> be around 10-20% of dry matter. Straw s<strong>to</strong>red in <strong>the</strong> open (piles of bales in <strong>the</strong> field) can<br />
also be damaged <strong>by</strong> rainwater and <strong>the</strong> outer bales in <strong>the</strong> stack may rot and be lost. Problems can be<br />
avoided <strong>by</strong> choosing <strong>the</strong> s<strong>to</strong>rage sites care<strong>full</strong>y. If s<strong>to</strong>red damp and under cover, some self-heating can<br />
occur – a potential fire hazard.<br />
A number of estimates for <strong>the</strong> quantity of straw available across <strong>the</strong> UK have been made, however in<br />
reality it varies from year <strong>to</strong> year, depending on <strong>the</strong> harvest and on alternative market demand for straw.<br />
Existing traditional agricultural uses such as lives<strong>to</strong>ck bedding and feed, animal feed compounding, crop<br />
protection and composting consume significant and varying amounts of straw each year. 80<br />
78<br />
National and Regional Supply/demand balance for agricultural straw in Great Britain, Copeland, J., Turley, D., Central Science Labora<strong>to</strong>ry for <strong>the</strong><br />
NNFCC, 2008.<br />
79<br />
ETSU New and Renewable Energy: Prospects in <strong>the</strong> UK for <strong>the</strong> 21st Century: Supporting Analysis.<br />
80<br />
ETSU BM/04/00056/REP/3 (1999) Energy from Biomass: summaries of <strong>the</strong> biomass projects carried out as part of <strong>the</strong> Department of Trade and<br />
Industry’s New and Renewable Energy Programme Volume 5: Straw, poultry litter and energy crops.
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The Carbon Trust’s biomass study for 2003 estimated straw production <strong>to</strong> vary between 10 and 12 million<br />
<strong>to</strong>nnes per annum of which around 25% would be available for use in future energy solutions. 81 The<br />
Royal Commission on Environmental Pollution (RCEP) <strong>report</strong> indicated an availability of 24 million <strong>to</strong>nnes<br />
in 2002. 82 The Biomass Task Force, provided an estimate of 3-4.5 million <strong>to</strong>nnes of straw available for<br />
energy generation per annum. 83.84 The most recent <strong>report</strong> <strong>by</strong> <strong>the</strong> CSL in 2008 estimated that 60% of<br />
straw could be recovered from <strong>the</strong> field, approximately 2.75 – 4 t/ha, and of this 4.9 million <strong>to</strong>nnes would<br />
be available for non-traditional uses in Great Britain, once operational and future straw burning Power<br />
Stations had been taken in<strong>to</strong> account (<strong>to</strong>tal straw arising 11.9 million <strong>to</strong>nnes).<br />
Most of <strong>the</strong>se figures refer only <strong>to</strong> England and Wales. Work for SEERAD indicated that most of <strong>the</strong><br />
straw in Scotland has a <strong>read</strong>y market and <strong>the</strong>re is no or very little surplus in Scotland. 85<br />
The straw arising figures below have used <strong>the</strong> assumption of 3.5 <strong>to</strong>nnes of straw produced per ha in <strong>the</strong><br />
UK, <strong>to</strong>ge<strong>the</strong>r with an availability of 25% for non-traditional uses (such as future energy solutions and<br />
fuels) as described in <strong>the</strong> Carbon Trust <strong>report</strong>. 86<br />
Using <strong>the</strong> above assumptions, an estimation of <strong>the</strong> straw arisings can be made, as well as <strong>the</strong> amount of<br />
straw that might be available for non-traditional uses such as energy generation and transport fuels.<br />
81 Biomass sec<strong>to</strong>r review for <strong>the</strong> Carbon Trust, 2005, Paul Arwas Associates and Black & Vetch Ltd.<br />
82 Royal Commission on Environmental Pollution, 2004, Biomass as a renewable energy source, www.rcep.org.uk/biomass/Biomass%20Report.pdf<br />
83 According <strong>to</strong> Defra Statistics <strong>the</strong> amount of land on which cereals were harvested varied from 3,014,000 <strong>to</strong> 4,026,000 ha over <strong>the</strong> pass 20 years. As<br />
<strong>the</strong> yield of straw varies from 3-4 t/ha, this translates in<strong>to</strong> a range of just over 9Mt just over 16Mt of straw produced in <strong>the</strong> UK per annum. The<br />
availability of straw for energy will <strong>the</strong>n depend on <strong>the</strong> market for alternative use, but is typically about a third of <strong>the</strong> <strong>to</strong>tal available. See:<br />
www.defra.gov.uk/esg/publications/auk/200/3-2.xls<br />
84 Biomass Task Force <strong>report</strong> <strong>to</strong> Government, Oc<strong>to</strong>ber 2005.<br />
85 MLURI, SAC and AEA Technology 2003 Energy from Crops in Scotland. Timber and Agricultural residues Technical Annex.<br />
86 J Nix Farm Management Handbook, 3 rd Edition 2005.<br />
55
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Table 24 Prediction of straw arisings and availability for non-traditional uses.<br />
Year<br />
Region Straw Estimation<br />
(‘000 <strong>to</strong>nnes)<br />
2003 2004 2005 2006 2007 2008<br />
East Midlands Total Straw<br />
Straw available non-<br />
2630 2673 2564 2513 2606<br />
traditional use 658 668 641 628 651<br />
East of Total Straw 1951 2035 1915 1899 1980<br />
England Straw available nontraditional<br />
use 488 509 479 475 495<br />
North East Total Straw<br />
Straw available non-<br />
478 491 471 456 472<br />
traditional use 120 123 118 114 118<br />
North West Total Straw<br />
Straw available non-<br />
266 298 272 262 267<br />
traditional use 67 74 68 66 67<br />
South East Total Straw 1451 1473 1408 1388 1423<br />
and London Straw available nontraditional<br />
use 363 368 352 347 356<br />
South West Total Straw<br />
Straw available non-<br />
1236 1290 1207 1186 1217<br />
traditional use 309 322 302 297 304<br />
West Midlands Total Straw<br />
Straw available non-<br />
923 955 909 890 927<br />
traditional use 231 239 227 223 232<br />
Yorkshire and Total Straw 1444 1514 1436 1383 1450<br />
Humber Straw available nontraditional<br />
use 361 378 359 346 363<br />
England Total Straw available nontraditional<br />
use 2595 2682 2546 2494 2586<br />
Scotland Total Straw<br />
Straw available non-<br />
1551 15889 1493 1428 1463 1638<br />
traditional use 388 397 373 357 366 410<br />
Wales Total Straw<br />
Straw available non-<br />
144 153 139 130<br />
traditional use 36 38 35 32<br />
Nor<strong>the</strong>rn Total Straw 125 123 126 120 112<br />
Ireland Straw available nontraditional<br />
use 31 31 31 30 28<br />
UK - Total Straw available nontraditional<br />
use 3049 3149 2984 2912<br />
As can be seen from <strong>the</strong> above data, <strong>the</strong>re is potentially considerable resource available without<br />
disturbing traditional markets. Dry straw has an energy content of around 18GJ/dry <strong>to</strong>nnes, which is<br />
independent of straw type.<br />
Availability<br />
Agricultural residues are generally large in volume and bulky <strong>to</strong> transport. As such transportation costs<br />
usually prohibit movement of <strong>the</strong>se residues significant distances. High density straw bales are an<br />
exception but it remains a low value commodity and any facility intending <strong>to</strong> make use of <strong>the</strong>se residues<br />
would ideally be constructed near <strong>to</strong> a significant supply of resource and so would be at local or regional<br />
scale.
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In terms of straw, <strong>the</strong> CSL Report identified that Wales and Scotland have straw deficits, while England is<br />
a net exporter of straw once regional lives<strong>to</strong>ck demand had been subtracted from <strong>the</strong> arisings. In addition<br />
<strong>the</strong> conversion of straw <strong>to</strong> energy products would remove <strong>the</strong> straw from <strong>the</strong> fields, removing a nutrient<br />
source (see Appendix 1 for <strong>the</strong> cost quantification of this nutrient source). The decision whe<strong>the</strong>r <strong>to</strong> sell<br />
straw is a balance between <strong>the</strong> price, soil type and suitability for reincorporation, timing for <strong>the</strong> next crop<br />
and <strong>the</strong> cost of replacement fertiliser.<br />
Poultry Litter<br />
The vast majority of poultry raised for meat, broilers, are farmed using intensive farming methods, with <strong>the</strong><br />
use of bedding. This enables easy collection of <strong>the</strong> residues produced, which are commonly high in solid<br />
content with little liquid present. The litter is also usually high in ammonia. 80 The fresh manure is<br />
approximately 75% water, but dries considerably over <strong>the</strong> time it spends in <strong>the</strong> enclosed house. 87<br />
Bedding materials are usually wood shavings, shredded paper or straw, which become mixed with<br />
droppings.<br />
Traditionally poultry litter was applied <strong>to</strong> <strong>the</strong> land as a fertiliser, but as with cow and pig slurry, <strong>the</strong> rise in<br />
poultry production and <strong>the</strong> decreasing availability of land mean that <strong>the</strong> potentially deleterious<br />
environmental impacts are being recognised and <strong>the</strong> traditional litter disposal methods are being<br />
discouraged. Poultry litter is considered a waste under <strong>the</strong> Waste Incineration Directive (WID), and<br />
<strong>the</strong>refore any plant that utilises this resource must be compliant with <strong>the</strong> requirements of WID.<br />
It is estimated that each fowl has <strong>the</strong> equivalent output of 0.036 kg/day (litter plus excreta), with a dry<br />
matter content of 70%. 88 The calorific value of poultry litter is between 8.8 89 and 15 GJ/t and <strong>the</strong> moisture<br />
content varies between 20-50%, 90,91 i.e. a calorific content that is about half that of anthracite coal (32-35<br />
MJ.Kg).<br />
Using <strong>the</strong> litter output estimation of 0.036kg/bird/day and assuming a calorific value of 9 GJ/t estimations<br />
of <strong>the</strong> regional output of poultry litter and its potential energy content are made in Table 25.<br />
Table 25 Total Fowl Numbers raised on bedding, <strong>by</strong> region for <strong>the</strong> UK<br />
Fowls raised on Energy Content<br />
Region<br />
bedding<br />
(GJ)<br />
East Midlands 17,361,450 5,625,110<br />
East of England 22,853,361 7,404,489<br />
North East 2,133,092 691,122<br />
North West 5,809,647 1,882,326<br />
South East inc. London 5,857,657 1,897,881<br />
South West 12,363,066 4,005,633<br />
West Midlands 13,688,062 4,434,932<br />
Yorkshire and Humber 11,888,774 3,851,963<br />
England - Total 91,955,109 29,793,455<br />
Nor<strong>the</strong>rn Ireland 13,923,000 411,052<br />
Scotland 5,388,040 1,745,725<br />
Wales 4,303,711 1,394,402<br />
UK - Total 115,729,164 37,496,249<br />
87<br />
From http://ohioline.osu.edu/b804/804_3.html<br />
88<br />
Poultry Manure (litter and Excreta) in England and Wales in Relation <strong>to</strong> <strong>the</strong> Regional Electricity Companies, ADAS, 1993,<br />
http://www.berr.gov.uk/files/file14939.pdf<br />
89<br />
Estimated average calorific values of fuels – 2004, BERR, http://www.berr.gov.uk/files/file19273.xls<br />
90 st<br />
ETSU R-122: New and Renewable Energy: Prospects for <strong>the</strong> UK for <strong>the</strong> 21 Century, Supporting Analysis.<br />
91<br />
Poultry litter as a fuel, World’s Poultry Science Journal, 49, 175-177, Dagnall, S., 1993.<br />
57
58<br />
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The estimated poultry litter resource in <strong>the</strong> UK is around 1.3 million <strong>to</strong>nnes as a significant proportion of<br />
birds are free range, and <strong>the</strong>re will still be considerable sp<strong>read</strong>ing <strong>to</strong> land occurring. 92 Approximately half<br />
of <strong>the</strong> 1.3 million <strong>to</strong>nnes is al<strong>read</strong>y committed <strong>to</strong> EPRL (Energy Power Resources Limited) energy from<br />
waste plants, generally from <strong>the</strong> largest commercial poultry farmers. Such plants are at Thetford, Eye<br />
and Westfield, <strong>the</strong> centres of <strong>the</strong> UK poultry industry (see later for more information).<br />
4.5.3 Conclusion<br />
Controlled agricultural wastes such as sacks, chemical residues etc are <strong>to</strong>o heterogeneous <strong>to</strong> be a viable<br />
feeds<strong>to</strong>ck.<br />
Agricultural residues have a large potential <strong>to</strong> be utilised for energy. The residues split in<strong>to</strong> two types –<br />
dry residues that can be utilised through combustion, and wet residues that have <strong>the</strong> potential <strong>to</strong> be<br />
utilised through AD. In both cases, <strong>the</strong> data for <strong>to</strong>tal arisings do not represent availability for energy as<br />
significant amounts of <strong>the</strong>se materials are used in traditional applications. In addition arisings are<br />
seasonally dependent, straw only arises for a short period in late summer and must be s<strong>to</strong>red, slurries<br />
and manures are largely available only when animals are wintering, or in enclosed spaces. These two<br />
fac<strong>to</strong>rs make <strong>the</strong> availability of residues for energy uncertain and a function of market conditions at any<br />
one time.<br />
We were unable <strong>to</strong> find information on <strong>the</strong> impact that <strong>the</strong> step change in deployment implied <strong>by</strong> <strong>the</strong><br />
Renewable Energy Strategy would have on alternative uses. This may have detrimental effects on some<br />
affected sec<strong>to</strong>rs that will not be offset <strong>by</strong> <strong>the</strong> increases energy business.<br />
4.6 Forestry Residues<br />
4.6.1 Definition<br />
Woodland covers an estimated 2.8 million hectares in <strong>the</strong> UK mainland, of which 1.57 million ha is conifer<br />
and 1.17 million ha broadleaf. 93 On <strong>the</strong> UK mainland, <strong>the</strong> highest proportion of woodland is in Scotland,<br />
49%, England has 41% and Wales has 10%. Nor<strong>the</strong>rn Ireland has a woodland area of 56,997 ha. 94<br />
4.6.2 Composition<br />
Forestry residues are defined as those parts of a tree left on <strong>the</strong> forest floor after harvesting and not<br />
recovered for commercial purpose. Such material originates from forests and woodlands, as primary<br />
processing co-products and from arboricultural arisings.<br />
Forest and woodland residues include: 95<br />
• Harvesting residues: tips of stems (a diameter of less than 7cm) and side branches.<br />
• Small round-wood: small stems removed from side branches with a diameter of 7-14 cm. 96<br />
• Poor quality wood: trees large enough <strong>to</strong> be used for timber, but of such poor quality <strong>the</strong>y would<br />
o<strong>the</strong>rwise be left on site or sold as firewood.<br />
92 st<br />
ETSU R-122: New and Renewable Energy: Prospects for <strong>the</strong> UK for <strong>the</strong> 21 Century, Supporting Analysis.<br />
93<br />
Addressing <strong>the</strong> land use issues for non-food crops, in response <strong>to</strong> increasing fuel and energy generation opportunities, NNFCC 2008,<br />
http://www.nnfcc.co.uk/metadot/index.pl?id=8253;isa=DBRow;op=show;dbview_id=2539<br />
94<br />
Forest Service, 2002. Facts and Figures, http://www.forestserviceni.gov.uk/factfigures01-02.pdf<br />
95<br />
About Woodfuel, Forest Research, 2003,<br />
http://www.eforestry.gov.uk/woodfuel/pages/AboutWoodfuel.jsp#Primaryprocessingcoproducts<br />
96<br />
Although it could be argued that small round-wood is not a forestry residue but a product. In <strong>the</strong> reference cited small round-wood is included <strong>to</strong><br />
show <strong>the</strong> maximum potential availability. Availability of this resource will depend on price and market conditions.
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By utilising <strong>the</strong> above resources from currently under managed woodlands, as outlined in <strong>the</strong> Forestry<br />
Commissions Wood Fuel Strategy (2006), 97 <strong>the</strong>se woodlands could contribute significantly <strong>to</strong> <strong>the</strong> arisings<br />
of forestry residues available for conversion <strong>to</strong> energy or transport fuels.<br />
A potential disadvantage that would need <strong>to</strong> be accounted for is <strong>the</strong> negative effects of removing this<br />
material from a forest, which if removed in excess could result in a decline in soil quality and structure, a<br />
decline in water quality and a decline in carbon sequestration. 98<br />
Production from commercial forestry systems is usually more complex than for annual or perennial energy<br />
crops, since <strong>the</strong> composition of <strong>the</strong> biomass obtained is a mixture of <strong>the</strong> above. 93<br />
The figures used in this section are based on a detailed <strong>report</strong> <strong>by</strong> McKay et al. (2003), <strong>the</strong> Forestry<br />
Commission for <strong>the</strong> DTI, published in 2003. Any detailed information on <strong>the</strong> methodology used <strong>to</strong><br />
calculate <strong>the</strong> forestry residue arising is available from this <strong>report</strong>. McKay et al. (2003) does not provide<br />
forestry residue data for Nor<strong>the</strong>rn Ireland and this is <strong>the</strong>refore collected from o<strong>the</strong>r sources.<br />
Figures in ‘oven dried <strong>to</strong>nnes’ (odt) are often quoted in this area. This refers <strong>to</strong> wood that is completely<br />
dried (i.e. zero moisture content). In reality it is very difficult <strong>to</strong> produce such wood, particularly from virgin<br />
residues and wood fuel is typically available at a range of moisture contents. To overcome issues that<br />
variable moisture content creates for <strong>the</strong> comparison of wood (and o<strong>the</strong>r biomass) fuels, characteristics<br />
such as calorific value are often quoted for odt.<br />
4.6.3 Current arisings<br />
The map of Great Britain from RESTATS shows <strong>the</strong> resource availability of forestry residues. As <strong>the</strong><br />
arising data for forestry residues shows in <strong>the</strong> latter section of this chapter, a vast amount of forestry<br />
residue exists in <strong>the</strong> UK. However <strong>the</strong> availability of <strong>the</strong> resource is an issue since it is al<strong>read</strong>y marketed<br />
<strong>to</strong> o<strong>the</strong>r industries and any remaining residue left on <strong>the</strong> ground contributes <strong>to</strong> effective forestry<br />
management through decomposition and soil nutrient maintenance. Therefore this chapter provides <strong>the</strong><br />
forestry residue arising data, however <strong>the</strong>y are not necessary available for energy projects.<br />
97 A Woodfuel Strategy for England, Forestry Commission, 2006,<br />
http://www.forestry.gov.uk/pdf/fce-woodfuel-strategy.pdf/$FILE/fce-woodfuel-strategy.pdf<br />
98 Forest Residues, Cranfield University, Ian Truckell, http://www.cranfield.ac.uk/sas/naturalresources/research/projects/forestresidues.jsp<br />
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Figure 11 Resource map of forestry residues for <strong>the</strong> UK (oven dried <strong>to</strong>nnes per annum)<br />
(Source: RESTATS 99 – This Yield map was created for <strong>the</strong> EU funded AMOEBA project. For forestry <strong>by</strong>-products, residue fac<strong>to</strong>rs<br />
from management activities, related <strong>to</strong> hectares of crop, were used <strong>to</strong> derive details of <strong>the</strong> available biomass. The information is<br />
presented here in oven dried <strong>to</strong>nnes of material per acre and not per hectares)<br />
The data below gives an estimation of <strong>the</strong> present annual operationally available resource <strong>by</strong> UK region,<br />
i.e. <strong>the</strong> quantity that would be possible <strong>to</strong> make available at roadside, from within <strong>the</strong> Forestry<br />
Commission and private sec<strong>to</strong>r area, without considering existing industries that use <strong>the</strong>se sources. 100<br />
99 Final <strong>report</strong> September 2004, RESTATS: Renewable Energy Statistics Database for <strong>the</strong> United Kingdom, www.restats.org.uk/index.htm<br />
100 McKay H, Hudson J.B. and Hudson R.J (2003) Wood fuel resource in Britain: main <strong>report</strong> (FES B/W3/00787/REP/1, DTI/Pub URN 03/1436,<br />
http://www.berr.gov.uk/files/file15006.pdf. Additional <strong>report</strong>s supplied <strong>by</strong> <strong>the</strong> Forestry Commission, derived from <strong>the</strong>ir website,<br />
http://www.eforestry.gov.uk/woodfuel/pages/Results.jsp
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Table 26 Annual production of potential operationally available forestry residue <strong>by</strong> UK region within <strong>the</strong><br />
Forestry Commission and private sec<strong>to</strong>r area (not considering existing industries.)<br />
Region Forestry and<br />
Woodland<br />
Residue (odt pa)<br />
East Midlands 53,046<br />
East of England 70,489<br />
North East 82,956<br />
North West 86,063<br />
South East and London 94,994<br />
South West 125,633<br />
West Midlands 41,966<br />
Yorkshire and Humberside 63,285<br />
England Total 618,432<br />
Scotland 848,345<br />
Wales 607,701<br />
Nor<strong>the</strong>rn Ireland 101 83,860<br />
UK Total 2,074,478<br />
Although arising data is available for round-wood with diameters<br />
greater than 7cm, <strong>the</strong>se are more likely <strong>to</strong> be used for products and<br />
<strong>the</strong>y are not included in this <strong>report</strong> as a forestry residue.<br />
These estimates do not take economic feasibility in<strong>to</strong> account. For example, resource is not excluded on<br />
<strong>the</strong> basis that it may be <strong>to</strong>o expensive. The actual availability is likely <strong>to</strong> change over time, dependent on<br />
a host of fac<strong>to</strong>rs - including financial support, infrastructure and incentives, transportation costs,<br />
accessibility, harvesting costs, timber prices, and prices of competing co-product markets.<br />
In a separate estimate <strong>the</strong> Forestry Commission estimate that, of <strong>the</strong> <strong>to</strong>tal available resource, 10% of <strong>the</strong><br />
small round-wood and 100% of poor quality stem-wood, stem tips and branches could be made available<br />
<strong>to</strong> new wood fuel projects without serious disruption <strong>to</strong> existing wood-using industries. 97 These<br />
percentages are applied in <strong>the</strong> latter part of this chapter <strong>to</strong> calculate <strong>the</strong> available forestry residues in <strong>the</strong><br />
presence of existing industries.<br />
The figures in Table 26 allow a comparative assessment of <strong>the</strong> forestry and woodlands residues available<br />
for regions in <strong>the</strong> UK. However regional strategies may provide a better understanding of <strong>the</strong> most recent<br />
data on <strong>the</strong> arisings from specific regions, and several regions have produced such strategies. The<br />
criteria and assumptions used for <strong>the</strong> various strategies differ, which makes direct comparisons difficult,<br />
and thus it has not been attempted here.<br />
An alternative method <strong>to</strong> establish forestry residue is <strong>to</strong> use estimates of residue production per hectare.<br />
The two key types of woodland give rise <strong>to</strong> different levels of residue: 102<br />
• Conifer residue: approximately 1.5 odt per hectare per annum (odt/ha pa)<br />
• Broad-leaved residue: approximately 0.4 odt per hectare per annum (odt/ha pa).<br />
Using <strong>the</strong>se assumptions gives a similar, although higher, estimate of woodland residues, as compared <strong>to</strong><br />
Table 26. This is likely due <strong>to</strong> <strong>the</strong> wider scope of such an estimate – unlike that of McKay et al (2003), it<br />
includes forests managed <strong>by</strong> government departments, such as <strong>the</strong> Ministry of Defence and woodland<br />
owned <strong>by</strong> non-governmental organisations.<br />
101<br />
Nor<strong>the</strong>rn Ireland data derived using an alternative method estimated from <strong>the</strong> assumption of <strong>the</strong> residue available relative <strong>to</strong> <strong>the</strong> forestry area as<br />
specified in Table.28.<br />
102<br />
'UK industry wood fuel resource study: England, Wales and Scotland<br />
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Table 27 Forestry residue arisings in <strong>the</strong> UK, based on <strong>to</strong>tal area of 2.8 M ha, and estimates of residue/ha pa 93<br />
Residue<br />
Broad-Leaf<br />
Residue<br />
Conifer<br />
Total<br />
Residue (odt<br />
pa)<br />
Broadleaf Conifer<br />
Region (‘000 ha) (‘000 ha) (odt pa) (odt pa)<br />
England 757 367 302,800 550,500 853,300<br />
Wales 127 158 50,800 237,000 287,800<br />
Scotland<br />
Nor<strong>the</strong>rn<br />
293 1,048 117,200 1,572,000 1,689,200<br />
Ireland 103 15 56 595 83,265 83,860<br />
UK - Total 1,177 1,573 470,800 2,359,500 2,830,300<br />
The <strong>report</strong> <strong>by</strong> McKay et al (2003) does not provide <strong>the</strong> equivalent data for Nor<strong>the</strong>rn Ireland, hence <strong>the</strong> arising data for Nor<strong>the</strong>rn<br />
Ireland in Table 26 has been estimated using <strong>the</strong> above method.<br />
4.6.4 Primary processing co-products<br />
Definition and Composition<br />
The process of converting trees in<strong>to</strong> usable wooden products creates considerable wastage.<br />
Approximately 50% of <strong>the</strong> volume of stem wood that is sold <strong>to</strong> sawmills is usually converted in<strong>to</strong> timber<br />
products such as planks, ba<strong>to</strong>ns, etc. 100 The remainder is commonly called co-product and can include<br />
bark, chips, off cuts and sawdust. Such co-products are normally sold, used for a variety of different<br />
purposes including paper and panel boards manufacture. Hence <strong>the</strong>se products often al<strong>read</strong>y have an<br />
existing market. However, it is anticipated that 10% of all co-products would be available as fuel sources<br />
without major effects on existing industries.<br />
Current Arisings<br />
Table 28 outlines <strong>the</strong> primary processing co-product arising in Great Britain. It can be seen that<br />
approximately 2% is used as wood fuel, most of which is used <strong>by</strong> <strong>the</strong> sawmills <strong>the</strong>mselves. The latest<br />
figures indicate that 83% of co-product is consumed <strong>by</strong> <strong>the</strong> panel board industries.<br />
Table 28 Proportions of primary processing co-products sold for fur<strong>the</strong>r use. 100<br />
Sold <strong>to</strong> Wood Processing<br />
Industries<br />
O<strong>the</strong>r Sales<br />
Weight Co-product Weight Co-product Weight<br />
Co-product (odt pa)<br />
(odt pa)<br />
(odt pa)<br />
Sawdust 158,742 Sawdust 12,890 Sold as bark 95,664<br />
Slabwood 1,039 Slabwood 48 Burnt for heat 11,931<br />
Peeled<br />
Peeled<br />
Disposed<br />
Chips 487,570 Chips 12,161 rubbish/burning 797<br />
Unpeeled<br />
Unpeeled<br />
Total co-<br />
Chips 63,652 Chips 5,411 products 859,002<br />
O<strong>the</strong>r 5,203 Firewood 2,941 O<strong>the</strong>r 953<br />
Exploring <strong>the</strong> arisings at a regional level produces <strong>the</strong> following results:<br />
• Almost half (47%) of <strong>the</strong> co-product originates from Scottish mills, with 34% from England and<br />
19% from Wales.<br />
• Within England <strong>the</strong>re are striking contrasts in arisings with <strong>the</strong> West Midlands accounting for 35%<br />
of English production and 12% of British output but <strong>the</strong> neighbouring East Midlands producing<br />
less than one tenth of <strong>the</strong> table below.<br />
103 Forest Service, 2002. Facts and Figures, http://www.forestserviceni.gov.uk/factfigures01-02.pdf
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Table 29 Regional arising of co-products 104,105<br />
4.6.5 Arboriculture Arisings<br />
Region<br />
Sawmill Co-product<br />
(odt pa)<br />
East Midlands 7,664<br />
East of England 24,577<br />
North East 50,615<br />
North West 37,899<br />
South East 22,191<br />
South West 27,204<br />
West Midlands 100,460<br />
Yorkshire and Humberside 18,969<br />
England - Total 289,579<br />
Scotland 403,538<br />
Wales 165,783<br />
Nor<strong>the</strong>rn Ireland 100,000<br />
UK - Total 958,900<br />
Definition and Composition<br />
Arboriculture sources of wood residues include <strong>the</strong> products of felling, thinning and pruning of trees, and<br />
include residues from maintenance of trees in roadside and public areas throughout <strong>the</strong> UK. Arboricultural<br />
arising data does not exist for Nor<strong>the</strong>rn Ireland.<br />
The residues are usually left on-site in <strong>the</strong> form of chippings or removed <strong>to</strong> landfill. Only a small<br />
proportion is currently used for energy end markets.<br />
The estimations of arboricultural arisings are based on a questionnaire analysis of arboricultural<br />
companies, tree officers and local authorities. 100 Total values for stem wood, branch wood, wood chips<br />
and foliage produced and subsequently sold was ga<strong>the</strong>red. This information was scaled up <strong>by</strong> multiplying<br />
<strong>the</strong> respondent average <strong>by</strong> <strong>the</strong> <strong>to</strong>tal number of contrac<strong>to</strong>rs in each region.<br />
Current Arisings<br />
The South East, including London, contributes about 25% of <strong>the</strong> English resource, while Yorkshire and<br />
Humberside and <strong>the</strong> East Midlands also have substantial arisings: <strong>the</strong>se three regions provide in <strong>to</strong>tal<br />
more than half <strong>the</strong> arisings in Britain. As with <strong>the</strong> o<strong>the</strong>r resources, actual availability of forestry residues<br />
will be dependent on <strong>the</strong> prices offered for wood fuel end uses in comparison <strong>to</strong> those being offered <strong>by</strong><br />
competing markets.<br />
104 The data is taken from About Woodfuel, Forest Research, 2003. The data is derived from <strong>the</strong> 2000 Annual Sawmill Survey and <strong>the</strong> co-incident<br />
Biennial Sawmill Survey carried out <strong>by</strong> <strong>the</strong> Forestry Commission Economics and Statistics Unit (McKay et al 2003). It is based on a voluntary survey<br />
where <strong>the</strong> data from <strong>the</strong> response is scaled up <strong>to</strong> national scale, which is a source of error.<br />
105 The Committee for Agriculture and Rural Development Report in<strong>to</strong> Renewable Energy and Alternative Land Use Nor<strong>the</strong>rn Ireland Assembly, 2007,<br />
http://www.niassembly.gov.uk/agriculture/2007mandate/<strong>report</strong>s/390708R.htm<br />
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Table 30 Aboricultural arisings for Great Britain.<br />
Total Arboricultural Non-marketed Aboricultural<br />
Regions<br />
Arisings (odt pa)<br />
Arisings (odt pa)<br />
East Midlands 63,451 50,636<br />
East of England 46,656 37,357<br />
North East 15,525 11,133<br />
North West 39,445 25,979<br />
South East 157,344 119,160<br />
South West 34,830 27,012<br />
West Midlands 15,445 7,115<br />
Yorkshire and Humber 72,329 23,814<br />
Scotland 16,146 12,448<br />
Wales 11,000 6,841<br />
Great Britain - Total 472,171 321,495<br />
Due <strong>to</strong> <strong>the</strong> voluntary nature of providing this data <strong>the</strong> above figures should be taken as an estimate.<br />
Figure 12 illustrates <strong>the</strong> relative proportion of material produced from <strong>the</strong>se activities.<br />
53%<br />
4%<br />
20%<br />
23%<br />
Foliage<br />
Wood chips<br />
Branch w ood<br />
Stem w ood<br />
Figure 12 Arboricultural arisings <strong>by</strong> <strong>the</strong> material produced (odt/annum)<br />
Potential Forestry resource, without serious disruption <strong>to</strong> existing wood using industries<br />
It is estimated that if all existing forests were actively managed for timber production and material not<br />
suited for use <strong>by</strong> existing markets (e.g construction and board manufacturers) was recovered, 1.9 million<br />
odt of wood from coniferous forest and 2.3 million odt of wood from broadleaved forest could be<br />
harvested each year, giving a <strong>to</strong>tal current forestry biomass resource of 4.2M odt. 93
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It should be noted though that this figure ignores environmental constraints such as long-term site<br />
sustainability, and physical and economic constraints such as cost of harvesting and extracting this<br />
material from <strong>the</strong> forest.<br />
Making several assumptions on market availability allows <strong>the</strong> availability of arboricultural arisings <strong>to</strong> be<br />
calculated, without serious disruption of existing wood using industries. 100<br />
Assumptions on available arisings:<br />
• 10% of <strong>the</strong> small round-wood<br />
• 100% of poor quality stem-wood, stem tips and branches<br />
• 10% of sawmill product<br />
• On average, 70% of arboricultural arisings<br />
• 100% of material from clearance of utilities and roadside maintenance<br />
The <strong>to</strong>tal potential operationally available forestry residue quantity in Great Britain, in <strong>the</strong> absence of<br />
competing markets, is 3.12 million odt per annum. The main material is small round-wood, followed <strong>by</strong><br />
sawmill co-product (potential <strong>to</strong> contribute around 1.03 and 0.86 million odt per annum respectively), with<br />
arboricultural arisings providing about 14% of <strong>the</strong> <strong>to</strong>tal. Approximately equal quantities are available in<br />
England and Scotland but <strong>the</strong> composition is substantially different. Arboricultural arisings form <strong>the</strong> major<br />
element in England though sawmill co-product, small round-wood, and branches are all significant<br />
components. In Scotland and Wales, small round-wood and sawmill co-products are <strong>the</strong> dominant<br />
resources with all o<strong>the</strong>r resource streams playing only a minor part at <strong>the</strong> moment. It may be argued that<br />
small round-wood is in fact a product and not a residue, however it has been considered that 10% of<br />
small round-wood may be available for use without serious disruption <strong>to</strong> existing wood using industries,<br />
hence it is included within <strong>the</strong> arisings data. 100<br />
Table 31 Current potential operationally available forestry residue resources <strong>by</strong> region, taking in<strong>to</strong> account<br />
competing markets<br />
Total Forests<br />
and Woodlands<br />
(odt pa)<br />
Arboricultural<br />
arising<br />
(odt pa)<br />
Region<br />
Sawmill Coproduct<br />
(odt pa)<br />
East Midlands 39,940 7,664 50,636 98<br />
East of England 45,123 24,577 37,357 107<br />
North East 21,689 50,615 11,133 83<br />
North West 53,678 37,899 25,979 118<br />
South East 50,888 22,191 119,160 192<br />
South West 77,911 27,204 27,012 132<br />
West Midlands<br />
Yorkshire and<br />
23,102 100,460 7,115 131<br />
Humberside 35,654 18,969 23,814 78<br />
England - Total 347,985 289,579 301,933 939<br />
Scotland 302,392 403,538 12,448 718<br />
Wales 157,707 165,783 6,841 330<br />
Great Britain - Total 1,987<br />
Total<br />
(‘000 odt pa)<br />
Future Arisings<br />
Information presented here is an approximation of all British forests and woodlands. There is great<br />
uncertainty about <strong>the</strong> future climate and <strong>the</strong> response of forests <strong>to</strong> that climate. 106 This applies <strong>to</strong> both<br />
direct effects (e.g. in <strong>the</strong> absence of nutrient and water limitations, growth is expected <strong>to</strong> increase due <strong>to</strong><br />
106 Forestry Commission, 2002, National Inven<strong>to</strong>ry of Woodland and Trees http://www.forestresearch.gov.uk/pdf/niengland.pdf/$FILE/niengland.pdf<br />
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increased CO2 and temperature) and indirect effects (e.g. higher winter temperatures are expected <strong>to</strong><br />
increase <strong>the</strong> fecundity of deer and reduce tree growth through increased browsing).<br />
In addition harvesting and thinning plans are not binding and will be influenced <strong>by</strong> a range of fac<strong>to</strong>rs:<br />
policy related, practical and commercial. These are likely <strong>to</strong> have significant consequences for future<br />
forestry residue resources even though <strong>the</strong>y cannot be quantified at <strong>the</strong> moment. 100<br />
• Forestry residue forecast<br />
Forestry residue in <strong>the</strong> form of small round-wood, poor quality stems, branches, tips and foliage<br />
from traditional forestry is expected <strong>to</strong> remain relatively stable at just under 2 million odt per<br />
annum up <strong>to</strong> 2020.<br />
• Private Sec<strong>to</strong>r residue forecast<br />
Small round-wood, poor quality stems, stem tips, branches and foliage <strong>to</strong>ge<strong>the</strong>r increase <strong>to</strong> 1.35<br />
million odt <strong>by</strong> 2012-2016, followed <strong>by</strong> a slight decrease 1.3 million odt <strong>to</strong> 2020.<br />
• Public Sec<strong>to</strong>r residue forecast<br />
Available biomass from <strong>the</strong> public sec<strong>to</strong>r is about half that predicted for private sec<strong>to</strong>r.<br />
Considering small round-wood, tips, branches and foliage (<strong>the</strong>re is no equivalent category <strong>to</strong> poor<br />
quality stems in <strong>the</strong> public sec<strong>to</strong>r), <strong>the</strong> prediction is that <strong>to</strong>tal biomass remains around 617k odt pa<br />
across Great Britain for 2007 – 2016, after which it falls slightly <strong>to</strong> reach 599k odt per annum <strong>by</strong><br />
2021.<br />
Table 32 Summary of future Woodland Arisings across Great Britain, private and public sec<strong>to</strong>r.<br />
Country Forecast Period Total Arising<br />
(odt pa)<br />
Scotland 2007-2011 931,062<br />
2012-2016 1,033,598<br />
2017-2021 1,019,815<br />
Wales 2007-2011 274,794<br />
2012-2016 260,346<br />
2017-2021 242,563<br />
England 2007-2011 664,083<br />
2012-2016 669,653<br />
2017-2021 637,862<br />
Nor<strong>the</strong>rn Ireland 107 2020 21,000 – 30,000<br />
• Primary processing co-products forecast<br />
o The proportions of smaller and poor quality arisings are expected <strong>to</strong> remain stable in <strong>the</strong><br />
near future. However <strong>the</strong> availability of larger dimension material is expected <strong>to</strong> increase<br />
substantially. For example, stem-wood of 18+cm diameter is forecasted <strong>to</strong> increase from<br />
3.8 million odt per annum in 2003-2006 <strong>to</strong> 5.4 million odt per annum in 2017-2021.<br />
Assuming that <strong>the</strong> sawmilling sec<strong>to</strong>r uses this resource, co-product will increase<br />
proportionately.<br />
o In addition <strong>the</strong>re is some indication that, compared <strong>to</strong> <strong>the</strong> present harvest, <strong>the</strong> form of<br />
larger dimension material is poorer than in material that will reach felling age in <strong>the</strong> next<br />
20 years or so years. Conversion efficiency is <strong>the</strong>refore expected <strong>to</strong> fall with a<br />
concomitant increase in co-product unless saw-milling technology can make parallel<br />
improvements.<br />
o In Nor<strong>the</strong>rn Ireland <strong>the</strong> forecast for 2020 is 50,000 – 200,000 odt pa, depending on<br />
whe<strong>the</strong>r a minimum or maximum scenario is pursued.<br />
107 Assessment of <strong>the</strong> potential for bioenergy development in Nor<strong>the</strong>rn Ireland, AEA, 2008,<br />
http://www.detini.gov.uk/cgi-bin/downutildoc?id=2314.
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• Arboricultural forecast<br />
Although operationally available arboricultural arisings cannot be forecast with any certainty, it is<br />
estimated that it is unlikely <strong>to</strong> change dramatically. However, it is expected that arboricultural<br />
arisings will increase. This can be found in more detail Appendix 1.<br />
4.6.6 Conclusions for Forestry Residues<br />
The UK has considerable natural wood resource, one that is not <strong>full</strong>y exploited at <strong>the</strong> moment and thus<br />
<strong>the</strong>re is considerable room for use of this material in future energy solutions. However, traditional and<br />
existing markets must be borne in mind, as must market conditions that will affect <strong>the</strong> cost of such a<br />
resource. In addition <strong>the</strong> environmental implications of removing significantly more natural wood arisings<br />
from land, and <strong>the</strong> impact this may have on future land quality and embedded carbon need fur<strong>the</strong>r<br />
assessment.<br />
The figures discussed here are <strong>the</strong> maximum practicable resource. For such quantities <strong>to</strong> be available a<br />
market for <strong>the</strong> product must exist and funding or incentives would be needed <strong>to</strong> set up <strong>the</strong> equipment and<br />
s<strong>to</strong>rage necessary. Currently <strong>the</strong>re are limited supply chain connections, thus this quantity of wood could<br />
not be brought <strong>to</strong> <strong>the</strong> market in a short timeframe.<br />
The availability and feasibility of using wood based fuels is dependent on <strong>the</strong> policy framework. One such<br />
recent example of <strong>the</strong> Woodfuel Strategy for England (2006) has a target <strong>to</strong> bring an additional 2 million<br />
<strong>to</strong>nnes of woodfuel <strong>to</strong> <strong>the</strong> market, annually <strong>by</strong> 2020 from forestry residues supported <strong>by</strong> o<strong>the</strong>r sources<br />
such as arboricultural arisings and recovered wood. All <strong>the</strong> wood resource described above is clean,<br />
untreated wood, and is <strong>the</strong>refore eligible as biomass fuels under <strong>the</strong> current legislation, and are exempt<br />
from <strong>the</strong> Waste Incineration Directive.<br />
4.7 Conclusions<br />
Waste, both controlled wastes and biological residues, represents a massive potential resource in <strong>the</strong> UK.<br />
Although significant amounts of such materials are al<strong>read</strong>y recycled, especially from MSW waste<br />
streams, or recycled on<strong>to</strong> land, as with many agricultural residues, a considerable amount of waste still<br />
exists and disposing of it is a challenge.<br />
Much of <strong>the</strong> residual waste that is disposed of through incineration or <strong>to</strong> landfill could potentially be more<br />
efficiently utilised, and may be a feeds<strong>to</strong>ck for <strong>the</strong> generation of energy or transport fuels.<br />
Summary of Waste Arisings<br />
• Municipal Solid Waste (MSW) is comprised of a very large range of materials, and <strong>to</strong>tal waste<br />
arisings are increasing. Data quality is good, and in 2007/08 <strong>the</strong> UK MSW arisings were 344<br />
million <strong>to</strong>nnes. Even if <strong>the</strong> level produced <strong>by</strong> each household were <strong>to</strong> remain constant, <strong>the</strong><br />
increasing number of households will result in increasing arisings. Recycling initiatives decrease<br />
<strong>the</strong> proportion of waste going straight for disposal, and <strong>the</strong> level of recycling is increasing each<br />
year. Most growth forecasts use a growth rate of 0.75% per annum.<br />
• Commercial and Industrial waste (C&I) is also comprised of a very large range of materials, with<br />
levels at 83 million <strong>to</strong>nnes in 2002/03. Overall levels of industrial waste are decreasing, while<br />
levels of commercial wastes are increasing. Again, recycling initiatives decrease <strong>the</strong> proportion<br />
of waste going straight for disposal, and <strong>the</strong> level of recycling is increasing each year, although in<br />
general recycling is not as advanced as for MSW. Growth rates have been taken as 1% per<br />
annum for commercial waste, and 0% per annum for industrial waste.<br />
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• Construction and Demolition waste (C&D) is largely comprised of mineral waste, with small<br />
amounts of wood, plastics and metals. Most investigation of this waste stream has been<br />
concerned with recycling <strong>the</strong> mineral proportion in<strong>to</strong> aggregate. Of <strong>the</strong> three controlled waste<br />
streams is produces <strong>the</strong> greatest amount, estimated at 118.6 million <strong>to</strong>nnes of waste in 2005.<br />
• Biosolids are produced from waste water treatment sites, as <strong>the</strong> main <strong>by</strong>-product. Data quality is<br />
generally good and in 2004-5 1.72 Mt of dry bio-solids were produced. Estimations are that this<br />
will increase <strong>to</strong> 2.5 Mt <strong>by</strong> 2030 due <strong>to</strong> an increasing number of households and tighter waste<br />
water and pollutions controls through legislation.<br />
• Agricultural residues include <strong>the</strong> wet residues of manures and slurries, and <strong>the</strong> dry residues of<br />
straw and poultry litter. Levels of available straw (after traditional uses) for 2006 were estimated<br />
<strong>to</strong> be 2.9 million <strong>to</strong>nnes for <strong>the</strong> UK, while poultry litter with an energy content of 37 million GJ was<br />
produced. Manures and slurries from cattle were estimated <strong>to</strong> produce a <strong>to</strong>tal, collectable, 9.9<br />
million kg/day of volatile solids, pigs 669 thousand kg/day of volatile solids and fowls 1.8 million<br />
kg/day of volatile solids. Accurate current and future arisings are difficult <strong>to</strong> predict as <strong>the</strong> sec<strong>to</strong>r<br />
is so dependent on wea<strong>the</strong>r, farming practices and markets. Apart from poultry litter, where<br />
approximately 50% is al<strong>read</strong>y committed <strong>to</strong> energy from waste plants, <strong>the</strong> residues are recycled<br />
<strong>to</strong> land.<br />
• Forestry residues arise from forests and woodlands, primary processing co-products and<br />
arboricultural work. Total available forestry residues in <strong>the</strong> UK are estimated <strong>to</strong> be 1,987 odt per<br />
annum, although it is unlikely this <strong>full</strong> amount could be realised for energy, and <strong>the</strong> data quality is<br />
generally uncertain. Some future estimations show an increase of material available, but no<br />
significant changes are expected.
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5 Arisings of components suitable for<br />
energy<br />
Chapter 4 presented an overview of <strong>the</strong> waste arisings <strong>by</strong> origin across <strong>the</strong> UK. In this chapter we<br />
discuss those components that are commonly cited as suitable for energy and fuel solutions.<br />
Each of <strong>the</strong> waste types discussed here is a subsection of, and a combination of, those al<strong>read</strong>y detailed<br />
above. The arisings presented here <strong>the</strong>refore do not represent additional arisings, but ra<strong>the</strong>r double<br />
counting.<br />
Many of <strong>the</strong>se streams are <strong>to</strong> some degree al<strong>read</strong>y collected separately and used directly for energy or<br />
being traded as fuel. This is a tendency that will increase as demand for renewable fuels increases as a<br />
result of <strong>the</strong> Renewables Obligation and Renewable Heat Incentive.<br />
Immediately identifiable arisings that could provide a biomass resource include:<br />
1. Wood residues: forestry (e.g. thinnings), virgin and treated wood processing waste, used wood.<br />
2. Agricultural residues: dry residues such as straw, husks and poultry litter, and wet residues such<br />
as manures and slurries.<br />
3. Municipal solid wastes including refuse derived fuels, kitchen wastes and garden wastes.<br />
4. Industrial and commercial wastes which include food and drink processing residues, tallow, meat<br />
and bone meal, pulp and paper sludges and liquors, textile residues, recovered vegetable oils.<br />
Those waste materials that have adequate data available, have been discussed. The pulling <strong>to</strong>ge<strong>the</strong>r of<br />
information from different waste streams allows a comprehensive picture of <strong>the</strong> <strong>to</strong>tal resource <strong>to</strong> be given.<br />
5.1 Waste Wood<br />
Background<br />
In this section <strong>the</strong> arisings of treated and post-consumer waste wood are evaluated. Clean waste wood<br />
from untreated wood processing is included in <strong>the</strong> section on forest residues and not included here.<br />
Each year in <strong>the</strong> UK it is estimated that over 7.5 million <strong>to</strong>nnes of wood waste is produced, approximately<br />
1.8% of <strong>to</strong>tal UK waste arisings. Of this over 80% is landfilled, 16% recycled and reused, and energy<br />
recovered from 4%. 108 Taking in<strong>to</strong> account recent economic developments and <strong>the</strong> slowing of <strong>the</strong><br />
economy, it is likely that this amount will fall in <strong>the</strong> short term. Indeed <strong>the</strong>re are al<strong>read</strong>y <strong>report</strong>s that wood<br />
recyclers are dropping <strong>the</strong> fees <strong>the</strong>y charge <strong>to</strong> take in wood, as <strong>the</strong> levels being disposed of go down.<br />
The decrease is most noticeable from <strong>the</strong> construction sec<strong>to</strong>r, and is believed <strong>to</strong> be having a knock on<br />
effect on <strong>the</strong> chipboard and wood panel producers. 109<br />
The markets for virgin untreated wood have developed rapidly in recent years due <strong>to</strong> <strong>the</strong> expansion of<br />
biomass heating in particular. The use of waste wood has not developed in a similar way. Treated waste<br />
wood includes anything that has had a surface coatings applied <strong>to</strong> it such as paints and varnishes or<br />
impregnation with preservative. The Waste Incineration Directive (WID) requires that combustion of wood<br />
waste containing heavy metals or halogenated hydrocarbons must meet strict emissions limits; cleaner<br />
wood is excluded for <strong>the</strong> purpose of combustion, but mixtures are usually regarded as contaminated for<br />
<strong>the</strong> purposes of combustion. Thus it is possible <strong>to</strong> recover energy in <strong>the</strong> form of power and heat from this<br />
contaminated wood, but pollution abatement must be installed <strong>to</strong> ensure <strong>the</strong> emissions limits are not<br />
108 Carbon Balances and Energy Impacts of <strong>the</strong> Management of UK Wastes, Defra R&D Project WRT 237, ERM, 2006,<br />
http://www.resourcesnotwaste.org/members/conf-application-form/Carbon&Waste(ERM).pdf<br />
109 Wood recyclers slash gate fees, 04-02-2009, Lets recycle.com,<br />
http://www.letsrecycle.com/do/ecco.py/view_item?listid=37&listcatid=217&listitemid=10989<br />
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exceeded. 110 Waste wood could potentially become a valuable energy resource, but <strong>the</strong> market lacks<br />
tight specifications for <strong>the</strong> quality of wood sourced. 111<br />
One of <strong>the</strong> main barriers <strong>to</strong> utilisation of this resource is that <strong>the</strong> types and volumes of waste wood are<br />
largely unknown. 112,113 Treated and post-consumer waste wood is generated from a number of different<br />
sources: 112<br />
• Municipal solid waste (all waste collected under local authority contracts)<br />
• Industrial wood processing (such as furniture manufacture, including kitchen, office, exhibition or<br />
shop fitting furniture),<br />
• Industrial waste,<br />
• Commercial and business waste (e.g. from refurbishment),<br />
• Construction and demolition waste and<br />
• Packaging and pallets.<br />
Data sources<br />
The data used <strong>to</strong> compile this chapter is taken from sources such as Defra, <strong>the</strong> Environment Agency and<br />
WRAP (Waste and Resource Action Programme), in particular <strong>the</strong> 2005 WRAP <strong>report</strong> <strong>by</strong> Nikitas et al.<br />
which was identified as <strong>the</strong> most authoritative work <strong>to</strong> date, and reviews and ranks all previous sources.<br />
These comprehensive reviews and surveys of specific sec<strong>to</strong>rs have been used and extrapolated from <strong>to</strong><br />
generate a picture for regions of <strong>the</strong> UK. This method provides estimates but <strong>the</strong>re is a danger in putting<br />
<strong>to</strong>o much reliance on it – <strong>the</strong>re are big uncertainties and <strong>the</strong>re are also likely <strong>to</strong> be large variations with<br />
time, depending on economic activity, particularly if large companies leave <strong>the</strong> UK or change <strong>the</strong>ir<br />
business.<br />
Packaging waste does not come under any specific waste stream and so is covered briefly in Box 1.<br />
Box 1. Packaging waste<br />
Packaging waste is not a specific waste stream, but arises from municipal, commercial, industrial<br />
and construction waste streams. The most significant type of waste wood arisings are those from<br />
pallets, but in addition packaging waste wood is also generated from cases, boxes, crates, cable<br />
drums, casks and barrels. All of <strong>the</strong>se categories are largely made from softwood.<br />
Waste wood from packaging in <strong>the</strong> commercial and industrial sec<strong>to</strong>r was estimated <strong>to</strong> generate<br />
arisings of nearly 900,000 <strong>to</strong>nnes in 1998. Important quantities of packaging waste are also<br />
believed <strong>to</strong> arise on construction sites.<br />
Data on wood packaging waste across <strong>the</strong> different waste streams is available from Timcon<br />
(Timber Packaging and Pallet Confederation). The estimated <strong>to</strong>tal <strong>to</strong>nnage in <strong>the</strong> UK for 2004 was<br />
about 1.4 million <strong>to</strong>nnes in 2004. However, this data is taken from Prodcom, based on survey<br />
samples of UK manufacturers, and presumably importers and exporters. Timcon’s view is that this<br />
data is of poor quality.<br />
110 The potential use of waste wood in <strong>the</strong> North East as an efficient biomass fuel source , K Coombs,<br />
http://www.northwoods.org.uk/files/northwoods/publications/Northwoods_WasteWoodFuelSource.pdf<br />
111 The environmental regulation of wood, Environment Agency, http://www.environmentagency.gov.uk/static/documents/Business/ps005_2077240.pdf<br />
112 Review of wood waste arisings and management in <strong>the</strong> UK, 2005, Nikitas et al, Published <strong>by</strong> WRAP.<br />
113 ‘Waste wood as a Biomass Fuel’ – Defra, April 2008, ‘UK Biomass Strategy’ – Defra, May 2007
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5.1.1 Municipal Wood Waste<br />
Municipal wood waste comprises of disposal <strong>by</strong> households; for example, furniture, fencing, decking,<br />
wood cuts from DIY, garden wastes and wood packaging. Wood waste from <strong>the</strong> municipal stream is<br />
usually mixed with o<strong>the</strong>r waste and rarely available as a clean source. It would need <strong>to</strong> be separated,<br />
cleaned and processed before it would form a useful wood fuel source, unless it goes <strong>to</strong> mass burn<br />
incineration.<br />
Estimation of waste wood in <strong>the</strong> municipal waste stream is difficult as <strong>the</strong> data represents all household<br />
waste and rarely specifies <strong>the</strong> quantities of specific fractions. However a number of compositional studies<br />
have been performed and are used below.<br />
Current Arisings<br />
Considering <strong>the</strong> available compositional data for MSW waste streams in 2005, <strong>the</strong> estimate percentages<br />
shown in Table 33 were established.<br />
Table 33 Waste wood and furniture waste as a percentage of MSW waste streams<br />
Household Collection<br />
Bulky waste collections<br />
Civic Amenity Site waste<br />
Waste wood Furniture<br />
1.11% (Wales)<br />
1.91% (rest of UK)<br />
0.06% (Wales)<br />
0.18% (rest of UK)<br />
6.03% 37%<br />
12.53% (Wales)<br />
9.05% (rest of UK)<br />
5.86% (Wales)<br />
4.3% (rest of UK)<br />
Collection round nonhousehold<br />
waste 0.6% 0%<br />
Applying <strong>the</strong>se percentages <strong>to</strong> <strong>the</strong> most recent overall <strong>to</strong>nnages for MSW in <strong>the</strong> English Regions, Wales,<br />
Nor<strong>the</strong>rn Ireland and Scotland <strong>to</strong> provide an estimate for <strong>the</strong> waste wood arising in <strong>to</strong>nnes (and where<br />
possible values for English regions) yielded <strong>the</strong> following results: 114<br />
Table 34 Estimate of wood content of MSW in <strong>the</strong> UK for 2003/4, excluding furniture<br />
Wood Arisings (‘000 <strong>to</strong>nnes)<br />
Waste Stream England Nor<strong>the</strong>rn<br />
Ireland<br />
Scotland Wales UK<br />
Household Collection 356 12 38 12 418 (39%)<br />
Bulky Collections 37 1 7 2 47 (4%)<br />
Civic Amenity 498 23 37 13 572 (54%)<br />
Non Household Collection 22 0 3 2 27 (3%)<br />
Total Wood in MSW 913 37 85 29 1,065<br />
Clearly <strong>the</strong> dominant source of municipal wood is <strong>the</strong> Civic Amenity Sites, which in 2003/4 accounted for<br />
over half of <strong>the</strong> arisings, due <strong>to</strong> <strong>the</strong> presence of garden waste at CA sites.<br />
Furniture in Municipal Waste<br />
It has not been possible <strong>to</strong> identify a suitable percentage for wood composition for furniture in <strong>the</strong> MSW<br />
waste stream. The figures below also include coverings, surface treatments and glass.<br />
114 More up <strong>to</strong> date data is of MSW arising is available, however not in <strong>the</strong> detailed waste streams within MSW required for <strong>the</strong> calculation here.<br />
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Table 35 Estimate of furniture waste in MSW in <strong>the</strong> UK for 2003/4<br />
Wood Arisings (‘000 <strong>to</strong>nnes)<br />
Waste Stream England Nor<strong>the</strong>rn<br />
Ireland<br />
Scotland Wales UK<br />
Household Collection 34 1.1 3.6 0.7 39 (6%)<br />
Bulky Collections 230 6.9 43 11.5 291 (49%)<br />
Civic Amenity 236 11.1 17.7 6.1 271 (45%)<br />
Non Household Collection 0 0 0 0 0<br />
Total Wood in MSW 500 19 64 18 602<br />
Applying <strong>the</strong> waste wood arisings for 2003/4 <strong>to</strong> <strong>the</strong> waste arisings for that year (England, 29,114<br />
thousand <strong>to</strong>nnes) yields an arising figure of 3.13% for general waste wood and 1.72 for waste furniture<br />
wood. 115 These percentages have been applied <strong>to</strong> <strong>the</strong> most recent MSW arisings <strong>to</strong> give an alternative<br />
arisings figure, and yield <strong>the</strong> estimates in Table 36.<br />
Table 36 Estimation of Waste Wood arisings <strong>by</strong> region using 2007/-8 MSW figures<br />
Region Wood Waste (excl.<br />
furniture)<br />
(‘000 <strong>to</strong>nnes)<br />
Furniture Waste<br />
(‘000 <strong>to</strong>nnes)<br />
East Midlands 76 42<br />
East of England 95 52<br />
London 130 71<br />
North East 47 49<br />
North West 127 70<br />
South East 143 79<br />
South West 92 50<br />
West Midlands 93 51<br />
Yorkshire and Humber 90 49<br />
England - Total 892 513<br />
Nor<strong>the</strong>rn Ireland 34 19<br />
Scotland 94 52<br />
Wales 56 31<br />
UK - Total 1,076 584<br />
5.1.2 Construction and Demolition Waste Wood (C&D)<br />
Data for C&D waste is largely concerned with achieving aggregate recycling, and <strong>the</strong>refore includes only<br />
mineral waste. The Environment Agency estimate that 4 million <strong>to</strong>nnes of waste wood arise from <strong>the</strong><br />
construction industry every year. 116 Construction and demolition waste is usually classed as one<br />
category, but waste wood may arise from a number of different waste streams: 117<br />
• Construction<br />
o off-cuts from structural timbers,<br />
o timber packaging, scaffolding, cladding, etc.<br />
Wood is likely <strong>to</strong> be untreated or uncontaminated.<br />
115 Defra e-Digest Statistics for 2007/8, http://www.defra.gov.uk/environment/statistics/wastats/archive/mwb200708.xls<br />
116 Defra “Waste Wood for Biomass” quoting <strong>the</strong> study <strong>by</strong> Nikita et al (2005). They note that this figure is an average of <strong>the</strong> maximum and minimum<br />
estimates which are 7.9 million tpa and 2.2 million tpa respectively for <strong>the</strong> UK.<br />
117 Remade Scotland (2004) Woodwaste Arisings in Scotland Assessment of Available Data on Scottish
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• Demolition<br />
o Used structural timber, floorboards, joists, doors and frames etc.<br />
Wood is likely <strong>to</strong> be treated, painted, coated or varnished, all are ‘contaminated’.<br />
• Refurbishment - this would be a combination of <strong>the</strong> above<br />
• Destruction<br />
• Scaffolding<br />
Remade Scotland indicates that <strong>the</strong> specific types of waste wood from construction and demolition waste<br />
include:<br />
• cable drums<br />
• coated material<br />
• cladding<br />
• dimension timber<br />
• doors and door<br />
frames<br />
• fences<br />
• flooring<br />
• framing timbers<br />
• pallets and fencing<br />
• panels and engineered<br />
wood composites using<br />
adhesives<br />
• piles<br />
• poles<br />
• solid wood<br />
• stakes<br />
• window frames<br />
Traditionally much of this waste was disposed of in skips on site and was poorly segregated. However,<br />
<strong>the</strong>re have been advances in segregation and recycling of construction and demolition waste through <strong>the</strong><br />
introduction of <strong>the</strong> Site Waste Management Plans (SWMP) in April 2008 for sites greater than<br />
£300,000. 118 Small sites (under £300,000) still continue <strong>to</strong> skip <strong>the</strong> majority of <strong>the</strong>ir waste, most of which<br />
goes <strong>to</strong> landfill. Segregation is often more difficult on such sites due <strong>to</strong> <strong>the</strong> lack of time and resource <strong>to</strong><br />
undertake this activity.<br />
Current Arisings<br />
There are only a few data sets available for arisings of waste wood from C&D, and <strong>the</strong>se have been<br />
evaluated <strong>by</strong> Nikitas et al (2005). (See Appendix 1 for an evaluation of <strong>the</strong>se sources.)<br />
Taking 1.5% as <strong>the</strong> minimum value of C&D waste arisings that are waste wood, and assuming a<br />
maximum value of 12.44% as <strong>the</strong> upper limit (although this includes excavation waste, hence <strong>the</strong><br />
reduction <strong>to</strong> 7.22% as 42% of <strong>the</strong> C&D waste was established as excavation waste) produces <strong>the</strong> figures<br />
detailed in Table 37.<br />
Table 37 Estimated waste wood arisings (excluding reclaimed wood) from <strong>the</strong> C&D waste stream.<br />
UK Arisings of waste wood<br />
(‘000 <strong>to</strong>nnes)<br />
England Wales Scotland Nor<strong>the</strong>rn<br />
Ireland<br />
Total C&D waste arisings 88,900 5,000 6,300 900 101,100<br />
Minimum Estimate (1.5%) 1,330 80 90 140 1,640<br />
Maximum Estimate (7.22%) 6,410 360 450 70 7,290<br />
Average 3,870 220 270 40 4,400<br />
The above figures take no account of reclaimed wood, which is a fur<strong>the</strong>r 634,000 <strong>to</strong>nnes for <strong>the</strong> UK,<br />
yielding a <strong>to</strong>tal of 5,034,000 <strong>to</strong>nnes. However it is unlikely that reclaimed wood would be available for<br />
energy generation. There is a very significant difference between <strong>the</strong> minimum and maximum estimates,<br />
demonstrating <strong>the</strong> degree of uncertainty in <strong>the</strong> data, and <strong>the</strong> need for more detailed arisings figures <strong>to</strong> be<br />
generated.<br />
118 Defra 2008. Non-statu<strong>to</strong>ry guidance for site waste management plans.<br />
UK<br />
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5.1.3 Commercial and Industrial Waste Wood (C&I)<br />
The main sources of wood waste originating within <strong>the</strong> C&I waste stream are off cuts and wastes from:<br />
• Furniture manufacture<br />
• Manufacture of products for use in construction e.g. roofing timbers, joists, floorboards, doors and<br />
windows<br />
• Wood waste during manufacture of wooden packaging<br />
• Wood wastes from waste wooden packaging<br />
• Utility poles<br />
• Railway sleepers.<br />
A number of surveys have been conducted on specific industries within <strong>the</strong> C&I waste stream <strong>by</strong><br />
organisations such as <strong>the</strong> Environment Agency, British Furniture manufacturers (BFM), FIET, FIRA and<br />
TRADA. These data sources have been assessed <strong>by</strong> Nikitas et al (2005) and, in general, were rated as<br />
being of poor quality.<br />
The <strong>to</strong>tal C&I waste wood arisings were estimated <strong>to</strong> be 4,481,000 <strong>to</strong>nnes. General waste wood arisings<br />
were identified as <strong>the</strong> largest source of arisings, with <strong>the</strong> second largest contribution from panel board<br />
manufacture (which accounts for a quarter of all wood wastes arising from <strong>the</strong> C&I sec<strong>to</strong>r, but it is<br />
believed that much of this figure is consumed within <strong>the</strong> industry <strong>to</strong> generate process heat).<br />
25%<br />
12%<br />
1% 1%<br />
4% 1%<br />
56%<br />
O<strong>the</strong>r C&I w ood w aste<br />
Railw ay Sleepers<br />
Utility Poles<br />
Furniture Manufacture<br />
Panelboard Manufacture<br />
Construction Industry<br />
Product Manufacture<br />
Wooden Packaging<br />
Manufacture<br />
Figure 13 Waste wood arisings for C&I type activities<br />
Future Arisings for all waste streams<br />
The WRAP <strong>report</strong> <strong>by</strong> Nikitas et al (2005) is also <strong>the</strong> best source of predictions of future arisings of waste<br />
wood. A simple model forecast for <strong>the</strong> various waste streams up until 2015 was generated and <strong>the</strong><br />
results shown in<br />
Table 38 shows estimations for <strong>the</strong> future waste wood arisings , taking in<strong>to</strong> account <strong>the</strong> relevant<br />
legislations and targets such as <strong>the</strong> Landfill Directive, <strong>the</strong> Packaging Directive, <strong>the</strong> Landfill Tax and <strong>the</strong><br />
Aggregates Levy.
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Table 38 Estimations of future Waste wood arisings from various waste streams.<br />
Year<br />
MSW arisings<br />
(‘000 <strong>to</strong>nnes,<br />
no furniture)<br />
MSW furniture<br />
(‘000 <strong>to</strong>nnes)<br />
C&D<br />
(‘000 <strong>to</strong>nnes)<br />
C&I<br />
(‘000 <strong>to</strong>nnes)<br />
2008 1,147 648 5167 6,612<br />
2012 1,217 688 5271 6,678<br />
2015 1,273 719 5351 6,729<br />
Conclusions<br />
The UK produces a large quantity of waste wood, arising from a variety of waste streams. The specific<br />
data quality is largely poor. Overall it is estimated that over 7.5 million <strong>to</strong>nnes of waste wood are<br />
generated each year. The limiting fac<strong>to</strong>rs for <strong>the</strong> use of waste wood are <strong>the</strong> presence of any<br />
contaminants and <strong>the</strong> difficulty in sorting and segregating mixed waste streams <strong>to</strong> provide wood in <strong>the</strong><br />
form and quantity required. Most, if not all, of this wood will have been treated in some way, so if it is <strong>to</strong><br />
be used for energy or fuels this must be done in a WID compliant facility.<br />
In addition <strong>the</strong>re are alternative existing markets for wood waste. These include:<br />
• Use in panel board manufacture<br />
• Use <strong>to</strong> make horticultural surface products<br />
• Use <strong>to</strong> make animal bedding<br />
• Combustion in small scale wood burning boilers<br />
• Incineration with or without <strong>the</strong> recovery of energy<br />
Any large-scale effort <strong>to</strong> encourage <strong>the</strong> use of waste wood for energy or fuels generation will need <strong>to</strong> take<br />
<strong>the</strong>se established uses in<strong>to</strong> account.<br />
The wood recycling industry has significantly increased in size since 1996, when less than 200,000<br />
<strong>to</strong>nnes of waste wood was recycled. All of <strong>the</strong> companies conducting ei<strong>the</strong>r wood waste collection or<br />
sorting of <strong>the</strong> collected wood <strong>to</strong> produce products suitable for recycling are private sec<strong>to</strong>r companies.<br />
The amount of wood which was recycled in 2008 was 2.0 million <strong>to</strong>nnes, of which 1.1 million <strong>to</strong>nnes was<br />
used in panel board manufacture and 0.4 million <strong>to</strong>nnes was sent <strong>to</strong> biomass energy recovery facilities.<br />
5.2 Food Waste<br />
Background<br />
This section contains waste arising data for food waste, which has been split in<strong>to</strong> food waste arisings<br />
from households and food waste arisings from <strong>the</strong> commercial and industrial sec<strong>to</strong>r. For each of <strong>the</strong>se<br />
two sec<strong>to</strong>rs data is provided for England, Wales, Scotland and Nor<strong>the</strong>rn Ireland.<br />
Food waste amounts <strong>to</strong> 18-20 million <strong>to</strong>nnes each year, for which 6.7 million <strong>to</strong>nnes is discarded from UK<br />
households. The commercial and industrial sec<strong>to</strong>r contribute 1.6 million <strong>to</strong>nnes from retailers, 4.1 million<br />
<strong>to</strong>nnes from food manufacturers and 3 million <strong>to</strong>nnes from food service and restaurants. 119<br />
The proportion of food waste currently captured is low across <strong>the</strong> UK, most is sent <strong>to</strong> landfill.<br />
Correspondingly <strong>the</strong>re is scope for fur<strong>the</strong>r collection and utilisation of food waste. 120 Indeed, <strong>the</strong> Landfill<br />
Directive requires increasing collection up <strong>to</strong> 2020. Such waste could potentially be converted in<strong>to</strong><br />
compost, anaerobically digested and <strong>the</strong> gas collected, or, more exceptionally, <strong>the</strong>rmally treated.<br />
119 Non-Household Food Waste, WRAP, http://www.wrap.org.uk/retail/food_waste/nonhousehold_food.html<br />
120 Hogg. D, Barth. J, Schleiss. K, and Favoino. E , 2007, Dealing with Food Waste In <strong>the</strong> UK, Eunomia Research and Consulting for WRAP.<br />
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Future Arisings<br />
Predictions of future food waste arisings are difficult <strong>to</strong> make due <strong>to</strong> <strong>the</strong> significant amount of pressure<br />
and campaigns in operation at <strong>the</strong> moment, such as some councils collecting segregated food waste, and<br />
<strong>the</strong> WRAP ‘Love Food, Hate Waste’ campaign. However such campaigns generally take 5 years <strong>to</strong> have<br />
an impact, so <strong>the</strong> likelihood is that any decrease in arisings will be small over <strong>the</strong> next few years.<br />
5.2.1 Household Food Waste<br />
Household waste is a sub-section of Municipal Solid Waste (MSW). This waste is almost exclusively<br />
household food waste, but may contain a minor amount of commercial and industrial waste included<br />
where refuse collections include mixed domestic and commercial properties.<br />
Typical composition figures for MSW have been used <strong>to</strong> provide an estimate of food waste arisings. The<br />
<strong>report</strong> ‘Dealing with Food Wastes in <strong>the</strong> UK’ published in March 2007 quantified <strong>the</strong> amount of food waste<br />
from households, and have been used here <strong>to</strong> calculate regional food waste arisings. 120<br />
England<br />
• Data from Defra’s 2007/08 MSW figures (WRAP <strong>report</strong> used 2004/05 data).<br />
• Food waste composition level: 17.5%<br />
Nor<strong>the</strong>rn Ireland<br />
• Data from 2007/2008. 121<br />
• Food waste composition level: 19%.<br />
Scotland<br />
• Most recent data from SEPA’s 2006/2007. 122<br />
• Food waste composition level: 18%.<br />
Wales<br />
• Data from 2007/2008. 123<br />
• Food waste composition level: 18%.<br />
It is worth noting that <strong>the</strong> levels of food waste predicted above is in line with <strong>the</strong> numbers <strong>the</strong> Welsh<br />
Assembly Government (WAG) is releasing, but <strong>the</strong> local authorities in Wales are finding <strong>the</strong>se quantities<br />
are over-estimated, as cautioned against in <strong>the</strong> background section above. Estimations of food waste are<br />
shown in Table 39 below.<br />
121 Municipal waste Management Report – Nor<strong>the</strong>rn Ireland 2007/08, http://www.ni-environment.gov.uk/waste/municipal_data_<strong>report</strong>ing.htm<br />
122 Waste Data Digest 8 Data Tables (2006/07) http://www.sepa.org.uk/waste/waste_data/waste_data_digest.aspx<br />
123 Municipal Waste Management Report 2007/08, http://new.wales.gov.uk/statsdocs/env/sdr177-2008.pdf
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Table 39 Food waste from households <strong>by</strong> region (2007/08) using <strong>the</strong> appropriate composition level.<br />
Region Quantity of<br />
Household waste<br />
(‘000 <strong>to</strong>nnes)<br />
Quantity of Food<br />
Waste<br />
(‘000 <strong>to</strong>nnes)<br />
East Midlands 2,185 382<br />
East of England 2,841 497<br />
London 3,342 585<br />
North East 1,268 222<br />
North West 3,599 630<br />
South East 4,242 742<br />
South West 2,644 463<br />
West Midlands 2,662 466<br />
Yorkshire/Humber 2,504 438<br />
England - Total 25,287 4,425<br />
Nor<strong>the</strong>rn Ireland 928 176<br />
Scotland 2,995 539<br />
Wales 1,542 277<br />
UK – Total 30,752 5,417<br />
5.2.2 Industrial and Commercial Food Waste<br />
The Waste Strategy 2007 defines commercial and industrial waste as follows: 124<br />
• commercial waste: waste arising from wholesalers, catering establishments, shops and offices<br />
(in both <strong>the</strong> public and private sec<strong>to</strong>rs)<br />
• industrial waste: waste arising from fac<strong>to</strong>ries and industrial plants.<br />
The data for food waste arisings from commercial and industrial waste sources is limited and it has not<br />
been possible <strong>to</strong> provide a breakdown of food waste arisings from commercial and industrial sources<br />
across <strong>the</strong> different regions of each country. The analysis below focuses on <strong>the</strong> food waste element in<br />
<strong>the</strong> mixed waste streams, <strong>to</strong>ge<strong>the</strong>r with kitchen and canteen waste, where it has been identified<br />
separately.<br />
England & Wales<br />
In 2002/03 <strong>the</strong> Environment Agency under<strong>to</strong>ok a survey of Commercial and Industrial business across<br />
England and Wales, which ga<strong>the</strong>red data on <strong>the</strong> types and quantities of waste, of which food waste was<br />
one, and <strong>the</strong> disposal or recovery methods. 125 Although this data is now relatively old, <strong>the</strong> survey has not<br />
been repeated for England, and a new survey is currently underway in Wales, but not yet published.<br />
Scotland<br />
In November 2008 a <strong>report</strong> <strong>by</strong> Napier University in<strong>to</strong> Scotland’s Commercial and Industrial waste was<br />
published, which estimated that <strong>the</strong>re are 2.73 million <strong>to</strong>nnes of mixed waste (similar <strong>to</strong> household waste)<br />
from commercial and industrial sources of which 16.7% was food waste. 126<br />
Whilst o<strong>the</strong>r data and information is available regarding Commercial and Industrial waste in Scotland, <strong>the</strong><br />
focus of <strong>the</strong>se is often across business sec<strong>to</strong>rs, for example in <strong>the</strong> Waste Data Digest. This means that<br />
<strong>the</strong> necessary level of detail <strong>to</strong> provide a realistic estimate of overall food waste arisings is not possible. In<br />
124 Waste Strategy for England, Defra, http://www.defra.gov.uk/ENVIRONMENT/waste/strategy/<br />
125 Environment Agency, National Waste Production Survey 2002<br />
126 McLaurin. L, Dar<strong>by</strong>. P, and Raeside, R. (2008) Estimation of commercial and industrial waste produced in Scotland in 2006. Final <strong>report</strong> <strong>to</strong> <strong>the</strong><br />
Scottish Environment Protection Agency (SEPA). Centre for Statistics, Napier University.<br />
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comparison <strong>the</strong> Napier University Report provides an indication of <strong>the</strong> different waste streams within <strong>the</strong><br />
commercial and industrial sec<strong>to</strong>r and also includes compositional analysis for <strong>the</strong> mixed waste.<br />
Table 40 Industrial and Commercial Food Waste for England, Wales and Scotland<br />
Country Commercial Industrial<br />
Total<br />
(‘000 <strong>to</strong>nnes) (‘000 <strong>to</strong>nnes) (‘000 <strong>to</strong>nnes)<br />
England 127 6,067 4,121 6,189<br />
Wales 125 211 51 262<br />
Scotland 126 - - 457<br />
Note: Totals do not calculate correctly due <strong>to</strong> rounding<br />
O<strong>the</strong>r studies<br />
O<strong>the</strong>r studies have been undertaken, which focus and specific geographical areas or industry sec<strong>to</strong>rs.<br />
While reference <strong>to</strong> <strong>the</strong>se is not helpful in providing an overview for each country, <strong>the</strong>se <strong>report</strong>s would be<br />
able <strong>to</strong> provide a more detailed picture for specific areas.<br />
• Research undertaken for Defra and <strong>the</strong> Food and Drink Federation (FDF) provides a snapshot of<br />
food waste arisings across FDF members in 2006. 128 It was conducted at 236 sites, <strong>by</strong><br />
organisations with a combined turnover of £17bn. 129 The survey included data on packaging<br />
waste, mixed waste and food waste – shown in Table 41. Fur<strong>the</strong>r food waste arising will be in <strong>the</strong><br />
mixed food and packaging waste, however <strong>the</strong> composition of this waste stream was not<br />
considered <strong>by</strong> <strong>the</strong> study.<br />
Table 41 Unmixed food waste arisings from FDF members in 2006<br />
Country / RDA Food Waste<br />
(‘000 <strong>to</strong>nnes)<br />
Advantage West Midlands 205<br />
SWRDA 111<br />
London 23<br />
EMDA 98<br />
Yorkshire Forward 47<br />
EEDA 27<br />
SEEDA 23<br />
NWDA 25<br />
One North East 13<br />
England - Total 571<br />
Nor<strong>the</strong>rn Ireland 3<br />
Scotland 13<br />
Wales 18<br />
UK - Total 605<br />
• A study was conducted for <strong>the</strong> East of England Regional Assembly area, and published in May<br />
2008. 130 The study considered both green waste and food waste arisings, with a particular focus<br />
on <strong>the</strong> latter. It examined <strong>the</strong> future requirements for an increased number of facilities <strong>to</strong> treat<br />
separately collected bio-wastes from municipal and commercial and industrial waste streams. It<br />
considered waste arisings, availability, current treatment capacity and its spatial distribution,<br />
127 http://www.defra.gov.uk/environment/statistics/waste/wrindustry.htm<br />
128 http://www.fdf.org.uk/ - FDF members cover a third of <strong>the</strong> turnover for <strong>the</strong> food and drink sec<strong>to</strong>r.<br />
129 http://www.fdf.org.uk/publicgeneral/mapping_waste_in_<strong>the</strong>_food_industry.pdf<br />
130 Summary Report Regional Biowastes management Study:<br />
http://www.eera.gov.uk/GetAsset.aspx?id=fAAzADMANwB8AHwARgBhAGwAcwBlAHwAfAAwAHwA0
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technologies available, <strong>the</strong> current treatment technology gap, assumed waste growth and growth<br />
in <strong>the</strong> capture of bio-wastes. This study provides a detailed analysis of <strong>the</strong> Regional position,<br />
however many regions have not undertaken such studies, and whe<strong>the</strong>r <strong>the</strong>y do so in <strong>the</strong> future<br />
will depend on <strong>the</strong> regional priorities.<br />
Conclusion<br />
The UK produces significant amounts of food waste, <strong>the</strong> potential value of which is only just being<br />
realised. While MSW food waste arisings are considerable, estimated <strong>to</strong> be 5.4 million <strong>to</strong>nnes,<br />
Commercial and Industrial food waste arisings are estimated <strong>to</strong> be even higher at 6.9 million <strong>to</strong>nnes per<br />
annum.<br />
WRAP, whose recent campaign ‘Love food, hate waste’ focused on household food waste, have<br />
identified that when food waste collection schemes are set up <strong>the</strong> volume collected is often significantly<br />
less than that anticipated – believed <strong>to</strong> be due <strong>to</strong> people reducing <strong>the</strong>ir food waste once <strong>the</strong>y can see how<br />
much is being wasted.<br />
5.3 Tallow 131<br />
Background<br />
Tallow is an animal fat obtained <strong>by</strong> rendering animal carcases and waste from <strong>the</strong> food industry and as<br />
such its arisings would be considered under industrial waste arisings. Rendering is <strong>the</strong> process <strong>by</strong> which<br />
animal carcases and trimmings are crushed and heated <strong>to</strong> drive off <strong>the</strong> water, sterilise <strong>the</strong> material and<br />
allow <strong>the</strong> fats (tallow) and meat and bone meal (MBM) <strong>to</strong> be separated. Rendering is an energy intensive<br />
process and <strong>the</strong> industry has traditionally used some of <strong>the</strong> tallow it produces as fuel.<br />
Current Arisings<br />
The size of <strong>the</strong> UK tallow arisings is dependent on UK meat production, which effectively limits <strong>the</strong> tallow<br />
available <strong>to</strong> <strong>the</strong> UK <strong>to</strong> around 250,000 <strong>to</strong>nnes per annum, from 2 million <strong>to</strong>nnes of animal waste. The<br />
industry processes <strong>the</strong> <strong>by</strong>-products of approximately 2 million cattle, 10 million pigs, 14 million sheep and<br />
800 million chickens annually. The amount of tallow produced in <strong>the</strong> UK has been stable for a number of<br />
years, and is unlikely <strong>to</strong> change significantly in <strong>the</strong> foreseeable future.<br />
Estimates of <strong>the</strong> amount of tallow produced range from 200kT per annum <strong>to</strong> 290kT per annum depending<br />
on <strong>the</strong> definition of what is included and <strong>the</strong> reference year. 132 The consensus is that 220 – 240 kT is<br />
available in principle for industrial use.<br />
Currently all tallow produced is used for some economic purpose. None is disposed <strong>to</strong> landfill. The main<br />
uses are dictated <strong>by</strong> <strong>the</strong> category of tallow under <strong>the</strong> Animal By-products Regulations: 133<br />
Category 1 can only be used for burning or fuel production<br />
Category 2 can be used for industrial applications<br />
Category 3 can be used for human contact (e.g. in soaps and cosmetics).<br />
This influences <strong>the</strong> current uses: burning of (mainly category 1) tallow in boilers <strong>by</strong> <strong>the</strong> rendering industry<br />
<strong>to</strong> raise process heat and <strong>the</strong> use of category 2 and 3 tallow <strong>by</strong> <strong>the</strong> oleochemicals and soap industry. A<br />
breakdown of <strong>the</strong>se uses is shown in Figure 14 (Uniqema 2008), demonstrating that 43% of <strong>the</strong> tallow is<br />
used as a fuel source, and 33% for industrial applications. These figures exclude exports.<br />
131 Advice on <strong>the</strong> Economic and Environmental Impacts of Government Support for Biodiesel Production from Tallow, Report for <strong>the</strong> Department of<br />
Transport, 2008.<br />
132 Argent Energy, 2008; CIA2008; UKRA 2008; Uniqema 2008.<br />
133 See Chapter 2 for an explanation of <strong>the</strong>se terminologies.<br />
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Burning<br />
33%<br />
Pow er Generation<br />
3%<br />
Biodiesel<br />
7%<br />
Food<br />
8%<br />
Animal Feed<br />
16%<br />
Oleochemicals and<br />
soap<br />
33%<br />
Figure 14 Uses of tallow in <strong>the</strong> UK (kT p.a.)<br />
This is a ra<strong>the</strong>r different balance than found when considering <strong>the</strong> EU as a whole, where a much greater<br />
portion of <strong>the</strong> available tallow goes in<strong>to</strong> animal feed. 134<br />
Energy and Fuels from Tallow<br />
The end uses for tallow are changing, as <strong>the</strong> incentives for <strong>the</strong> production of biodiesel have made this<br />
feeds<strong>to</strong>ck attractive for fuel production. With a fixed amount of tallow available on <strong>the</strong> market, this can<br />
only be obtained <strong>by</strong> diverting tallow from existing applications such as burning or oleochemical and soap<br />
production.<br />
Tallow derived biodiesel is an established procedure. In <strong>the</strong> UK tallow bio-diesel is produced through <strong>the</strong><br />
FAME processes <strong>by</strong> Argent Energy in Mo<strong>the</strong>rwell at <strong>the</strong>ir 45 kT per annum capacity site (supplied with<br />
both tallow and used cooking oil). Their Ellesmere Port plant is currently under construction with a future<br />
capacity of 150 kT. 135<br />
Tallow biodiesel has a higher cetane number than plant oil biodiesel, resulting in cleaner and more<br />
efficient burning in diesel engines. However, it also has a higher cloud point because of <strong>the</strong> high levels of<br />
saturated fatty acids. This means that tallow biodiesel tends <strong>to</strong> crystallise out at low temperatures<br />
creating problems in engines. Used neat (100%) tallow biodiesel would not meet <strong>the</strong> European standard<br />
for biodiesel. However, when blended at low percentages in<strong>to</strong> conventional diesel <strong>the</strong> mixture meets<br />
relevant fuel quality standards.<br />
Conclusion<br />
Tallow is a long established <strong>by</strong>-product of <strong>the</strong> rendering process, with constant volumes produced in <strong>the</strong><br />
UK. Currently all tallow is used for some commercial purpose – traditionally high quality tallow was used<br />
in <strong>the</strong> chemicals and cosmetics industries, while low grade tallow was burnt for heat. The introduction of<br />
tallow for bio-diesel has al<strong>read</strong>y had a disruptive effect on traditional markets.<br />
134 EFPRA 2008, http://www.efpra.eu/content/default.asp?PageID=21<br />
135 Argent Energy 2008, http://www.argentenergy.com/articles/news/article_51.shtml
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5.4 Textiles Waste Arising<br />
Background<br />
It is estimated that more than 1 million <strong>to</strong>nnes of textiles are thrown away every year, most of which is<br />
post-consumer waste. At least 50% of <strong>the</strong> textiles that are thrown away are recyclable. However, <strong>the</strong><br />
proportion of textile wastes reused or recycled annually in <strong>the</strong> UK is only around 25%. 136 Besides postconsumer<br />
waste, post-industrial waste arises during yarn and fabric manufacture, <strong>the</strong> garment-making<br />
processes and from <strong>the</strong> retail industry. Textile waste arises as standard in two waste streams: MSW and<br />
C&I.<br />
Current Arisings<br />
Several sources have identified <strong>the</strong> proportion of textile waste in MSW as approximately 1.9%. 137<br />
Meanwhile C&I textile arisings are estimated <strong>to</strong> be 1-2% of <strong>the</strong> waste stream in Section 4.2.<br />
Table 42 Estimated textile waste arising in <strong>the</strong> UK <strong>by</strong> region in (‘000 <strong>to</strong>nnes)<br />
Region Textiles<br />
Textiles Total<br />
(1.9% of MSW) (1.5% of C&I)<br />
East Midlands 46 121 167<br />
East of England 58 98 156<br />
London 79 113 191<br />
North East 29 69 98<br />
North West 77 125 202<br />
South East 87 133 219<br />
South West 56 83 139<br />
West Midlands 57 109 166<br />
Yorkshire and Humber 54 167 221<br />
England - Total 542 1019 1560<br />
Nor<strong>the</strong>rn Ireland 20 24 44<br />
Scotland 65 80 145<br />
Wales 34 117 151<br />
UK - Total 661 1239 1900<br />
Current Disposal Methods<br />
At present, <strong>the</strong> majority of post-consumer textiles are collected <strong>by</strong> charities such as The Salvation Army,<br />
Scope and Oxfam. Such collec<strong>to</strong>rs sort <strong>the</strong> material, selling it on <strong>to</strong> merchants in <strong>the</strong> appropriate sec<strong>to</strong>rs.<br />
The Open University Household Waste Study shows that <strong>the</strong>re has been a year on year increase in <strong>the</strong><br />
proportion of households served <strong>by</strong> kerbside recycling collections for textiles: 16.8% in 2002, 29% in 2005<br />
and 44.7% in 2008.<br />
Some post-industrial waste is recycled as part of in-house procedures. This is more common in <strong>the</strong> yarn<br />
and fabric-manufacturing sec<strong>to</strong>rs. The rest, aside from going <strong>to</strong> landfill or incineration, is sold <strong>to</strong><br />
merchants via textile reclamation fac<strong>to</strong>ries that can handle a huge <strong>to</strong>nnage of textiles. The main routes for<br />
<strong>the</strong> material are:<br />
• High quality second hand clo<strong>the</strong>s and shoes are resorted for sending <strong>to</strong> charities in <strong>the</strong> UK<br />
and use in developing countries.<br />
• Lower quality textiles which are worn out are processed within <strong>the</strong> fac<strong>to</strong>ry <strong>to</strong> produce<br />
industrial wiping cloths.<br />
136 Textile recycling information sheet, Waste Online, http://www.wasteonline.org.uk/resources/InformationSheets/Textiles.htm, Analysis of household<br />
waste composition and fac<strong>to</strong>rs driving waste increases - Dr. J. Parfitt, WRAP, December 2002.<br />
137 Open University Household Waste Study, <strong>Jones</strong>, A., Nesaratnam, S., Porteous, A., 2008, Defra: 1.9%, National Household Waste Arising Survey:<br />
1.8% after recycling<br />
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• O<strong>the</strong>r textiles are fur<strong>the</strong>r graded for fibre reclamation <strong>by</strong> pulling <strong>the</strong> th<strong>read</strong>s of <strong>the</strong> textile and<br />
using it <strong>to</strong> produce new clo<strong>the</strong>s and blankets, and also mattresses.<br />
Textiles have an average GCV of 16MJ/kg and <strong>the</strong> stream is <strong>the</strong>refore viable for Energy from Waste<br />
projects. However due <strong>to</strong> <strong>the</strong> al<strong>read</strong>y existing market in recycling and <strong>the</strong> complexity involved in sorting<br />
MSW it could be difficult <strong>to</strong> utilise this as a separate feeds<strong>to</strong>ck.<br />
Textile waste is considered <strong>to</strong> be a high priority product within Defra’s Product Roadmap scheme due <strong>to</strong><br />
<strong>the</strong> high environmental and social impact - accounting for 5-10% of UK environmental impacts, partly due<br />
<strong>to</strong> <strong>the</strong> UK’s high consumption of clothing. 138,139<br />
Future Arisings<br />
A simple forecast for textile waste arising can be modelled on <strong>the</strong> assumption that <strong>the</strong> proportion of textile<br />
in C&I waste and MSW remain constant applied <strong>to</strong> <strong>the</strong> MSW and C&I waste forecasts. Such a prediction<br />
suggests that for <strong>the</strong> UK <strong>the</strong> <strong>to</strong>tal textile arisings will be 1,944,000 <strong>to</strong>nnes in 2010, rising <strong>to</strong> 2,042,000<br />
<strong>to</strong>nnes <strong>by</strong> 2020.<br />
Conclusion<br />
Textile wastes, estimated <strong>to</strong> be nearly 2 million <strong>to</strong>nnes from both MSW and C&I waste streams, are a<br />
waste stream where significant environmental benefits can be delivered through simple reuse. Only<br />
when textiles are very badly damaged or soiled does energy recovery and similar solutions become<br />
advisable.<br />
5.5 Paper Waste Arisings<br />
Background<br />
The UK consumes between 12 and 13 million <strong>to</strong>nnes of paper and board each year. 140 The main sources<br />
of waste paper and board arisings are from households (MSW) and from <strong>the</strong> Commercial and Industrial<br />
(C&I) waste stream. The paper/card waste arising from <strong>the</strong> Construction and Demolition (C&D) sec<strong>to</strong>r is<br />
considered <strong>to</strong> be negligible (any arisings would be from packaging used for construction materials).<br />
Municipal Solid Waste Arising<br />
Paper and cardboard is estimated <strong>to</strong> be 21% of <strong>the</strong> <strong>to</strong>tal arisings of MSW. 141 Such an estimation leads <strong>to</strong><br />
<strong>the</strong> arisings from <strong>the</strong> MSW figures for 2007/08 in Table 43 142<br />
138 EU Commission, Environmental Impact of Products, http://ec.europa.eu/environment/ipp/pdf/eipro_<strong>report</strong>.pdf<br />
139 Defra, 2008, Product roadmaps- Clothing, http://www.defra.gov.uk/environment/consumerprod/products/clothing.htm<br />
140 http://www.paper.org.uk/information/pages/statistics.html<br />
141 The Composition of Municipal Solid Waste in Wales. Report <strong>by</strong> AEA for <strong>the</strong> Welsh Assembly Government, December 2003<br />
142 e-Digest Statistics about: Waste and Recycling, Defra, 2008, http://www.defra.gov.uk/environment/statistics/waste/index.htm Waste Data Digest 8:<br />
Key facts and trends. SEPA, 2008, http://www.sepa.org.uk/waste/waste_data_menu/waste_data_digest.aspx, Welsh Assembly Government, 2008;<br />
Municipal Waste Management Report for Wales 2007-2008; Environment & Heritage Service, Municipal Waste Management Nor<strong>the</strong>rn Ireland 2005/06<br />
Summary Report.
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Table 43 Paper and board waste arising in MSW in <strong>the</strong> UK<br />
Region<br />
Paper and Cardboard<br />
(‘000 <strong>to</strong>nnes)<br />
East Midlands 507<br />
East of England 637<br />
London 871<br />
North East 318<br />
North West 851<br />
South East 958<br />
South West 615<br />
West Midlands 628<br />
Yorkshire and Humber 602<br />
England - Total 5,986<br />
Nor<strong>the</strong>rn Ireland 223<br />
Scotland 722<br />
Wales 378<br />
UK - Total 7,309<br />
5.5.1 Industrial and Commercial Waste Paper<br />
Paper and card are often source separated <strong>by</strong> Industrial and Commercial premises <strong>to</strong> some degree.<br />
Table 44 lists <strong>the</strong> sec<strong>to</strong>rs that produce <strong>the</strong> most paper and board waste. 143 The publishing, printing and<br />
recording sec<strong>to</strong>r produces <strong>the</strong> most paper and card from <strong>the</strong> industrial sec<strong>to</strong>r, but <strong>the</strong> <strong>to</strong>tal arisings of<br />
separately identified paper and card from <strong>the</strong> commercial sec<strong>to</strong>r are over twice those from <strong>the</strong> industrial<br />
sec<strong>to</strong>r. The <strong>to</strong>tal arisings of separately identified paper and cardboard in C&I waste are 8.6 million<br />
<strong>to</strong>nnes.<br />
143 Defra 2006, Industrial and commercial waste arisings <strong>by</strong> business sec<strong>to</strong>r and waste type,<br />
http://www.defra.gov.uk/environment/statistics/waste/index.htm<br />
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Table 44: Paper and board arising as a segregated stream from Industrial and Commercial sec<strong>to</strong>rs, 2006.<br />
Sec<strong>to</strong>r description Paper and<br />
cardboard<br />
(‘000 <strong>to</strong>nnes)<br />
I Food, drink and <strong>to</strong>bacco 262<br />
I Manufacture of pulp, paper and paper products 568<br />
I Publishing, printing and recording 1,331<br />
I Manufacture of chemicals and chemical products; cleaning<br />
159<br />
products, man-made fibres etc; rubber and plastic products<br />
I Manufacture of office machinery, computers, electrical, radio,<br />
television and communication equipment; medical and optical<br />
instruments and clocks<br />
82<br />
Total Industrial 2,656<br />
C Retail - mo<strong>to</strong>r vehicles, parts and fuel; wholesale; o<strong>the</strong>r retail 3,642<br />
C Travel agents, o<strong>the</strong>r business, finance, real estate and<br />
1,183<br />
computer related activities<br />
C Transport, s<strong>to</strong>rage, communications 328<br />
C Social work and public administration 291<br />
C Miscellaneous 201<br />
Total Commercial 5,976<br />
I: Industrial sec<strong>to</strong>r, C: Commercial sec<strong>to</strong>r<br />
The o<strong>the</strong>r source of paper/cardboard is from mixed/general category of C&I waste, approximately 31% of<br />
C&I arisings. This has been found <strong>to</strong> contain approximately 34% paper and card <strong>by</strong> weight, yielding<br />
about 7.1 million <strong>to</strong>nnes. 144 In <strong>to</strong>tal <strong>the</strong> arisings of paper and card in C&I waste is 15.7 million <strong>to</strong>nnes.<br />
This represents 23% <strong>by</strong> weight of <strong>to</strong>tal C&I arisings, and Table 45 gives estimates for <strong>the</strong> corresponding<br />
regional arisings.<br />
Table 45: Paper and board waste arising from C&I.<br />
Region<br />
Paper and Cardboard<br />
(‘000 <strong>to</strong>nnes)<br />
East Midlands 1,510<br />
East of England 1,727<br />
London 1,861<br />
North East 1,058<br />
North West 1,917<br />
South East 2,036<br />
South West 1,278<br />
West Midlands 1,671<br />
Yorkshire and Humber 2,561<br />
England - Total 15,619<br />
Nor<strong>the</strong>rn Ireland 368<br />
Scotland 1,219<br />
Wales 1,794<br />
UK - Total 19,000<br />
144 Determination of <strong>the</strong> Biodegradability of Mixed Industrial and Commercial Waste Landfilled in Wales for <strong>the</strong> Environment Agency, SLR, 2007,<br />
http://www.environment-agency.gov.uk/static/documents/Research/biodegwals_1913611.pdf
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Recycling<br />
Table 46 shows that <strong>the</strong> recycling rate for paper and card has increased from 34% in 1995 <strong>to</strong> 71% in<br />
2007. 145 The UK collected 8.5 million <strong>to</strong>nnes of paper for recycling in 2007, but as it only has capacity <strong>to</strong><br />
produce about 5 million <strong>to</strong>nnes of paper and card products, and thus 4 million <strong>to</strong>nnes of collected material<br />
is exported for recycling. 146<br />
Table 46: Paper and board recycling rates for <strong>the</strong> UK, accounting for imports and exports<br />
Year 1995 2000 2005 2007<br />
Recycling rate (Wt %) 34 41 62 71<br />
Forecast<br />
Assuming that <strong>the</strong>re is no increase in <strong>the</strong> proportion of paper and board arisings in MSW and C&I wastes,<br />
<strong>the</strong>n <strong>the</strong> predictions of general waste increase can be used <strong>to</strong> estimate that MSW paper and board waste<br />
will have risen <strong>to</strong> 7.6 million <strong>to</strong>nnes <strong>by</strong> 2010 and 8.0 million <strong>to</strong>nnes <strong>by</strong> 2020, and C&I paper and board<br />
waste will have risen <strong>to</strong> 19,320,000 <strong>to</strong>nnes in 2010 and 20,240,000 <strong>to</strong>nnes <strong>by</strong> 2020. Total estimated<br />
arisings of paper and cardboard in <strong>the</strong> UK will be about 28.2 million <strong>to</strong>nnes per annum in 2020.<br />
Conclusion<br />
There has been considerable interest in paper and board as a potential feeds<strong>to</strong>ck for <strong>the</strong> generation of<br />
energy. This waste stream is predicted <strong>to</strong> increase over <strong>the</strong> coming years, and as such should be a<br />
stable feeds<strong>to</strong>ck.<br />
5.6 Conclusions<br />
A number of materials are of particular interest for future energy and fuels production. Most are extracted<br />
from bulk, collected waste streams. These are:<br />
• Waste wood extracted from MSW, C&I and C&D waste streams, including all wood packaging<br />
waste. A large proportion of <strong>the</strong> wood will have been treated with a preservative, or similar, and<br />
<strong>the</strong>refore <strong>the</strong> waste must be used in a WID compliant site. Total UK MSW wood waste arisings<br />
are estimated <strong>to</strong> be 1.06 million <strong>to</strong>nnes, based on good quality data, while both C&D and C&I<br />
data sources are of poor quality, but estimations are that C&D arisings were 4.4 million <strong>to</strong>nnes,<br />
and C&I arisings were 4.48 million <strong>to</strong>nnes.<br />
• Food waste is a major waste stream, with a <strong>to</strong>tal of 18-20 million <strong>to</strong>nnes generated each year. Of<br />
this 6.7 million <strong>to</strong>nnes is from UK households, while <strong>the</strong> commercial and industrial sec<strong>to</strong>r also<br />
contributes <strong>to</strong> <strong>the</strong> food waste stream, with 1.6 million <strong>to</strong>nnes from retailers, 4.1 million <strong>to</strong>nnes<br />
from food manufacturers and 3 million <strong>to</strong>nnes from food service and restaurants.<br />
• Tallow is a product of <strong>the</strong> rendering industry, and all UK production, currently estimated <strong>to</strong> be<br />
250,000 <strong>to</strong>nnes per annum, is al<strong>read</strong>y used for some commercial function. Use of this material<br />
for alternative purposes, e.g. bio-diesel production, is al<strong>read</strong>y occurring and is disrupting<br />
traditional markets.<br />
• Textile waste arises mainly from MSW and C&I waste streams, estimated <strong>to</strong> be 1.9 million <strong>to</strong>nnes<br />
each year in <strong>the</strong> UK. Reuse of high and medium quality textiles offers significant environmental<br />
benefits, only when textiles are very badly damaged or soiled does energy recovery and similar<br />
solutions become advisable.<br />
145 Recovery and recycling of waste paper and board: 1993 – 2007, Defra, 2008,<br />
http://www.defra.gov.uk/environment/statistics/waste/download/xls/wrtb20.xls<br />
146 Key industry facts 2007. Confederation of Paper Industries, 2008.<br />
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• Paper waste arises largely from MSW and C&I waste streams, and <strong>to</strong>tals between 12 and 13<br />
million <strong>to</strong>nnes of recoverable paper and board each year, of which 7.3 million <strong>to</strong>nnes is from<br />
MSW, 2.7 million <strong>to</strong>nnes from industry and 6 million <strong>to</strong>nnes is from commercial waste. However<br />
much paper and board is thrown away in general waste so <strong>the</strong> <strong>to</strong>tal C&I waste may be 19 million<br />
<strong>to</strong>nnes. It is estimated that arisings of this waste material will increase <strong>by</strong> a small amount in <strong>the</strong><br />
future.<br />
The potential for <strong>the</strong>se fuels are summarised in Table 47
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Table 47 Summary of biomass based wastes arising across <strong>the</strong> UK (‘000 <strong>to</strong>nnes).<br />
Region MSW Wood<br />
Waste (inc.<br />
furniture)<br />
C&D Waste<br />
Wood<br />
C&I Waste<br />
Wood<br />
MSW Food<br />
Waste<br />
C&I Food<br />
Waste<br />
87<br />
Textiles<br />
MSW and<br />
C&I<br />
MSW Paper<br />
and<br />
Cardboard<br />
C&I Paper<br />
and<br />
Cardboard<br />
East Midlands 76 - - 382 - 167 507 1,510<br />
East of England 95 - - 497 - 156 637 1,727<br />
London 130 - - 585 - 191 871 1,861<br />
North East 47 - - 222 - 98 318 1,058<br />
North West 127 - - 630 - 202 851 1,917<br />
South East 143 - - 742 - 219 958 2,036<br />
South West 92 - - 463 - 139 615 1,278<br />
West Midlands 93 - - 466 - 166 628 1,671<br />
Yorkshire and Humber 90 - - 438 - 221 602 2,561<br />
England - Total 892 3,870 - 4,425 6,189 1560 5,986 15,619<br />
Nor<strong>the</strong>rn Ireland 34 40 - 176 - 44 223 368<br />
Scotland 94 270 - 539 457 145 722 1,219<br />
Wales 56 220 - 277 262 151 378 1,794<br />
UK - Total 1,660 4,400 4,481 5,417 6,908 1900 7,309 19,000<br />
Tallow has not been included in <strong>the</strong> above table as all production is currently utilised.
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6 Waste Management Legislation and<br />
Incentives<br />
Legislation and incentives are <strong>the</strong> most important drivers controlling waste management policy. Waste<br />
Framework Directives from <strong>the</strong> European Commission determine <strong>the</strong> broad direction of policy and fur<strong>the</strong>r<br />
directives and UK legislation determine <strong>the</strong> detail of its execution.<br />
The Renewables Obligation, Renewable Transport Fuels Obligation and future heat incentives will shape<br />
<strong>the</strong> industry and encourage <strong>the</strong> generation of heat both directly and <strong>by</strong> separation and manufacture of<br />
biomass fuel products.<br />
The main areas of legislation that national and regional waste strategies need <strong>to</strong> consider are <strong>the</strong> Waste<br />
Framework Directive, Environmental Permitting and <strong>the</strong> Landfill Directive.<br />
Waste Framework Directive<br />
Entered in<strong>to</strong> force December 2008<br />
The European Commission published a revised Waste Framework Directive (2008/98/EC) in November<br />
2008, and <strong>the</strong> UK has 2 years <strong>to</strong> transpose this in<strong>to</strong> law. This Directive sets a revised framework for<br />
waste management in <strong>the</strong> EU, and aims <strong>to</strong> encourage re-use and recycling of waste as well as simplifying<br />
current legislation. The main points of <strong>the</strong> Directive are:<br />
• A five-step hierarchy of waste management options, with waste prevention as <strong>the</strong> preferred<br />
option, and <strong>the</strong>n reuse, recycling, recovery (including energy recovery) and safe disposal, in<br />
descending order. The Directive classifies "energy efficient" incineration as recovery in an<br />
attempt <strong>to</strong> reduce consumption of fossil fuels.<br />
• Measures <strong>to</strong> encourage prevention of waste. Member States must design and implement<br />
waste prevention programmes, and <strong>the</strong> Commission is set <strong>to</strong> <strong>report</strong> periodically on progress<br />
concerning waste prevention.<br />
• Requirements for a 50% target for household recycling and reuse and 70% target for nonhazardous<br />
construction and demolition waste, both of which must be reached <strong>by</strong> <strong>the</strong> UK <strong>by</strong><br />
2020.<br />
Some departure from this hierarchy is permissible <strong>to</strong> deliver <strong>the</strong> best overall environmental outcome as justified<br />
<strong>by</strong> life cycle thinking.<br />
The Directive also deals with <strong>the</strong> issue of 'end of waste', clarifies <strong>the</strong> idea of recovery, disposal and <strong>by</strong>product,<br />
defines <strong>the</strong> conditions for mixing hazardous waste, introduces an "environmental objective" and<br />
moves <strong>to</strong>wards establishing technical minimum standards for certain waste management operations.<br />
The current EC Waste Framework Directive (75/442/EEC) requires <strong>the</strong> disposal, recovery, treatment,<br />
transport and collection of ‘controlled waste’ streams such as MSW, Hazardous Wastes, C&I and Inert<br />
wastes.<br />
Landfill Directive<br />
Entered in<strong>to</strong> force July 2001<br />
The European Commission Landfill Directive of 1999 (1999/31/EC) was passed in<strong>to</strong> English and Welsh<br />
law in 2002, and Scottish law in 2003. This aims <strong>to</strong> prevent, or minimise, <strong>the</strong> negative effects on both <strong>the</strong><br />
environment and human health caused <strong>by</strong> landfilling of wastes.
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One highly relevant aspect of this Directive <strong>to</strong> <strong>the</strong> production of fuels and energy is <strong>the</strong> requirement that<br />
<strong>the</strong> amount of biodegradable MSW sent <strong>to</strong> landfill in <strong>the</strong> UK <strong>to</strong> be reduced:<br />
• <strong>to</strong> 75% of 1995 levels <strong>by</strong> 2010,<br />
• <strong>to</strong> 50% of 1995 levels <strong>by</strong> 2013, and<br />
• <strong>to</strong> 35% of 1995 levels <strong>by</strong> 2020.<br />
Environmental Permitting Regulations (EPR) 147<br />
Entered in<strong>to</strong> force April 2008<br />
Environmental permitting combines Pollution Prevention and Control (PPC) 148 and waste management<br />
licensing in<strong>to</strong> a single system for England and Wales. Many facilities for waste or residue heat, power or<br />
fuel production will need <strong>to</strong> be licensed under <strong>the</strong>se regulations, although <strong>the</strong>re are lower size limits below<br />
which no license is required. For fur<strong>the</strong>r information on whe<strong>the</strong>r or not a facility comes under EPR <strong>the</strong><br />
opera<strong>to</strong>r should consult <strong>the</strong> Environment Agency which licenses most EPR sites.<br />
EPR covers a very wide range of industrial activities, but <strong>the</strong> main activities covered <strong>by</strong> <strong>the</strong>se regulations,<br />
and of relevance regarding <strong>the</strong> use of waste or residual biomass as a fuel, are:<br />
• Burning of any fuel or waste (in any type of plant)<br />
• Gasification and pyrolysis of any fuel or waste<br />
The requirement <strong>to</strong> apply for and hold a relevant permit applies whe<strong>the</strong>r <strong>the</strong> material is processed in a<br />
dedicated facility, intermittently or as an admixture. Permits are issued for <strong>the</strong> plant as operated in <strong>the</strong><br />
permit application. Variations in operation require a variation in <strong>the</strong> permit, so that changes in <strong>the</strong> fuel<br />
used in biomass plants will require a variation in <strong>the</strong> permit.<br />
The Waste Incineration Directive (WID)<br />
Entered in<strong>to</strong> force December 2002<br />
For waste combustion this licensing will also include consideration of <strong>the</strong> Waste Incineration Directive<br />
(WID). This Directive sets out stringent emissions limits from waste combustion. The WID applies <strong>to</strong><br />
incineration and co-incineration plants. Co-incineration plants include those plants where waste is used<br />
as a fuel or where it is disposed of at a plant where energy generation or production is <strong>the</strong> main purpose.<br />
149<br />
A plant will only be an incineration plant or a co-incineration plant if it burns waste as defined in <strong>the</strong> Waste<br />
Framework Directive (WFD). This definition is extremely broad and <strong>the</strong>re are, in effect, very few<br />
circumstances where <strong>by</strong>-products, co-products or residues are not classified as wastes. 150<br />
Agricultural and forestry residues are not defined as wastes and as such <strong>the</strong> WID will not apply <strong>to</strong> <strong>the</strong>ir<br />
combustion. However, <strong>the</strong>re are many wastes that contain biomass whose treatment is not so clear cut.<br />
In particular <strong>the</strong> treatment of <strong>the</strong> combustion of waste wood for <strong>the</strong> purposes of WID is complicated.<br />
Current Environment Agency guidance 151 is that all waste wood is a waste, but <strong>the</strong> combustion of certain<br />
types of untreated waste wood (i.e. waste wood that has not been treated with preservatives or coatings)<br />
is exempt from WID. However, <strong>the</strong> combustion of wood waste that contains halogenated hydrocarbons<br />
147<br />
The EPR are available from: http://www.opsi.gov.uk/si/si2007/uksi_20073538_en_3#pt2-ch1-l1g12 and guidance is provided on<br />
http://www.netregs.gov.uk/netregs/63143.aspx<br />
148<br />
For fur<strong>the</strong>r guidance on PPC see http://www.defra.gov.uk/environment/ppc/regs/index.htm and http://www.netregs.gov.uk/netregs/63432.aspx<br />
149<br />
Defra, Environmental Permitting Guidance: The Directive on <strong>the</strong> Incineration of Waste, 2008.<br />
150<br />
The EC has provided guidance on <strong>the</strong> definition of waste: CEC: COM(2007) 59 final COMMUNICATION FROM THE COMMISSION TO THE<br />
COUNCIL<br />
AND THE EUROPEAN PARLIAMENT on <strong>the</strong> Interpretative Communication on waste and <strong>by</strong>-products<br />
151 EA (2008) The environmental regulation of wood, Position Statement. www.environment-agency.gov.uk/commondata/acrobat/ps_005_2077240.pdf<br />
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or heavy metals will come under WID, as will <strong>the</strong> combustion of any source of waste wood that might be<br />
contaminated with ei<strong>the</strong>r of <strong>the</strong>se sets of chemicals.<br />
WID sets out details including <strong>the</strong> operating conditions, including gas temperatures and residence times,<br />
limits on emission levels for a range of substance <strong>to</strong> air and water including dioxins and <strong>the</strong> moni<strong>to</strong>ring<br />
requirements on <strong>the</strong>se substances.<br />
Renewable Energy Directive (RED)<br />
Published June 2009<br />
The RED, which came in<strong>to</strong> EU law in April 2009, is designed <strong>to</strong> help states progress <strong>to</strong>wards meeting <strong>the</strong><br />
EU 2020 target of 20% energy derived from renewable sources. The target for <strong>the</strong> UK is 15%. 152 Within<br />
<strong>the</strong> RED biomass is defined <strong>to</strong> include <strong>the</strong> biodegradable fraction of industrial and municipal wastes and<br />
residues from agriculture and forestry.<br />
There are two areas of RED that are important <strong>to</strong> wastes and residues; <strong>the</strong>se are <strong>the</strong> conditions provided<br />
for biofuels and those for biomass heat and power:<br />
Biofuels: Among o<strong>the</strong>r things <strong>the</strong> RED brings in sustainability requirements and <strong>report</strong>ing<br />
requirements for biofuels. Guidance on <strong>the</strong>se will be provided <strong>by</strong> <strong>the</strong> EC <strong>by</strong> early 2010. Biofuels<br />
produced from waste and residues (o<strong>the</strong>r than agricultural, aquaculture, fisheries and forestry<br />
residues) are exempted from some of <strong>the</strong>se sustainability requirements. The RED requires a<br />
greenhouse gas emission savings from biofuels of at least 35%, but it also states that <strong>the</strong> contribution<br />
made <strong>by</strong> biofuels produced from wastes and residues and <strong>the</strong> lignocellulosic component of biomass<br />
will be considered <strong>to</strong> be twice that made <strong>by</strong> o<strong>the</strong>r biofuels. This is a strong driver for <strong>the</strong> use of<br />
wastes and residues and for <strong>the</strong> development of processes using <strong>the</strong> lignocellulosic components of<br />
biomass.<br />
In addition in <strong>the</strong> calculation of default values for biofuels (Annex V), <strong>the</strong> Directive states: “Wastes,<br />
agricultural crop residues, including straw, bagasse, husks, cobs and nut shells, and residues from<br />
processing, including crude glycerine (glycerine that is not refined), shall be considered <strong>to</strong> have zero<br />
life-cycle greenhouse gas emissions up <strong>to</strong> <strong>the</strong> process of collection of those materials.” These default<br />
values will be subject <strong>to</strong> review. This simplification is positive for <strong>the</strong> use of straw and o<strong>the</strong>r harvest<br />
residues for energy that would have higher greenhouse gas emissions allocated from cultivation and<br />
alternative use under a <strong>full</strong> life cycle analysis. It would be more negative for manures and food<br />
wastes that would expect <strong>to</strong> be allocated a strong emissions reduction credit for avoided methane<br />
emissions from alternative disposal routes.<br />
Finally Member States may encourage <strong>the</strong> use of biofuels which give additional benefits, including <strong>the</strong><br />
benefits of diversification offered <strong>by</strong> biofuels made from waste and residues. This adds up <strong>to</strong> a<br />
considerable number of additional incentives <strong>to</strong> encourage <strong>the</strong> development of biofuels from wastes<br />
and residues.<br />
Biomass heat and power: In 2009 <strong>the</strong> Commission will examine whe<strong>the</strong>r or not <strong>to</strong> introduce<br />
sustainability requirements for all biomass for energy (including biomass for heat and power) similar<br />
<strong>to</strong> those for biofuels. The European Commission published <strong>the</strong> summary <strong>report</strong> of responses <strong>to</strong> its<br />
recent consultation on <strong>the</strong> requirement for sustainability criteria for biomass for energy (o<strong>the</strong>r than<br />
biofuels or bioliquids). This will provide input <strong>to</strong> <strong>the</strong> Commission's follow-up <strong>report</strong> planned for<br />
December 2009. 153<br />
An action plan for <strong>the</strong> implementation of <strong>the</strong> RED within UK law needs <strong>to</strong> be prepared <strong>by</strong> 30 th June 2010.<br />
152 Proposed Directive http://ec.europa.eu/energy/climate_actions/doc/2008_res_directive_en.pdf<br />
153 http://ec.europa.eu/energy/renewables/consultations/doc/results_public_consultation_biomass_sustainability_scheme.pdf
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Renewable Energy Strategy (RES)<br />
Published July 2009<br />
As part of <strong>the</strong> implementation process for RED <strong>the</strong> UK Government has produced a draft Renewable<br />
Energy Strategy. The current draft introduces a number of measures that are of relevance <strong>to</strong> wastes and<br />
residues, including <strong>the</strong> Renewable Heat Incentive. 154 It also recognises <strong>the</strong> importance of energy from<br />
waste for <strong>the</strong> UK and discusses measures <strong>to</strong> encourage WID-compliant combustion and raising<br />
awareness of <strong>the</strong> benefits of bioenergy including energy from waste. In addition it also introduces <strong>the</strong><br />
concept of sustainability for bioenergy, discusses <strong>the</strong> potential for imports and discusses <strong>the</strong> potential for<br />
building biomass and waste supply chains in <strong>the</strong> UK.<br />
Renewable Transport Fuel Obligation (RTFO)<br />
Entered in<strong>to</strong> force April 2008<br />
The Government’s Renewable Transport Fuel Obligation (RTFO), which came in<strong>to</strong> effect in April 2008,<br />
has since been amended following <strong>the</strong> conclusions of <strong>the</strong> Gallagher Review released in July 2008. The<br />
RFTO now requires road transport fuel suppliers <strong>to</strong> ensure that, <strong>by</strong> 2013, 5% of <strong>to</strong>tal road transport fuel<br />
supply in <strong>the</strong> UK is made up of renewable fuels, equivalent <strong>to</strong> around 2.5 billion litres of fuel per annum.<br />
These targets work on a volume basis, and <strong>the</strong>refore encourage use of <strong>the</strong> cheapest feeds<strong>to</strong>cks for <strong>the</strong><br />
generation of biofuels, commonly sugar and starch crops. It is recognised that <strong>the</strong>se biofuels are not <strong>the</strong><br />
most effective for Greenhouse Gas emissions reduction, and <strong>the</strong> long term policy is <strong>to</strong> introduce second<br />
generation biofuels with higher GHG savings potentials. GHG savings compared with petrol or diesel are<br />
typically 40-70% for biodiesel from oil seed rape and 30-70% for bioethanol from wheat, compared <strong>to</strong><br />
savings of 86-93% estimated for second generation biofuels.<br />
The UK Biomass Strategy 155<br />
Published May 2007<br />
The Biomass Strategy indicates that biomass will have a central role <strong>to</strong> play in meeting <strong>the</strong> EU target of<br />
20% renewable energy <strong>by</strong> 2020, and will likely have a more regional focus than <strong>the</strong> current energy<br />
networks. The Strategy covers <strong>the</strong> biomass generated as waste and residues, including agricultural<br />
residues, both wet and dry; forestry and horticultural residues; biodegradable content of MSW;<br />
biodegradable content of Commercial and Industrial waste.<br />
It will be necessary <strong>to</strong> increase <strong>the</strong> supply from organic waste materials such as manures and slurries,<br />
source-separated waste biomass and waste-derived solid recovered fuels. In particular faster growth in<br />
<strong>the</strong> development of AD is desired, including examination of how and whe<strong>the</strong>r economic or fiscal<br />
instruments can facilitate increased use of AD.<br />
The Biomass Strategy introduced a number of key initiatives that are relevant <strong>to</strong> biomass wastes and<br />
residues, including <strong>the</strong> Biomass Energy Centre web site; 156 <strong>the</strong> Biomass Capital Grants Scheme; 157 a<br />
review of <strong>the</strong> approach <strong>to</strong> Anaerobic Digestion 158 and a Woodfuel Strategy, which aims <strong>to</strong> bring 2 million<br />
green <strong>to</strong>nnes of wood (including forestry residues) on<strong>to</strong> <strong>the</strong> market <strong>by</strong> 2020.<br />
Proposed Renewable Heat Incentive (RHI)<br />
Proposed in <strong>the</strong> 2008 Energy Bill<br />
154<br />
In fact firm proposals for <strong>the</strong> Renewable Heat Incentive are introduced in <strong>the</strong> Heat and Energy Saving Strategy launched <strong>by</strong> <strong>the</strong> Government in<br />
February 2009.<br />
155<br />
The UK Biomass Strategy, www.defra.gov.uk/environment/climatechange/uk/energy/renewablefuel/pdf/ukbiomassstrategy-0507.pdf<br />
156<br />
See: http://www.biomassenergycentre.org.uk/portal/<br />
157<br />
For fur<strong>the</strong>r information see: http://www.defra.gov.uk/environment/climatechange/uk/energy/fund/<br />
158<br />
This has lead <strong>to</strong> a commitment of £10M for <strong>the</strong> Environmental Transformation Fund <strong>to</strong> fund AD projects in England.<br />
91
Under consultation in 2009<br />
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The Renewable Heat Incentive is likely <strong>to</strong> apply <strong>to</strong> <strong>the</strong> generation of renewable heat at all scales, through<br />
a range of technologies including biomass, solar hot water, air- and ground-source heat pumps, biomass<br />
CHP, biogas produced from anaerobic digestion, and biomethane injected in<strong>to</strong> <strong>the</strong> gas grid, although it<br />
will potentially be banded <strong>by</strong> size and technology.<br />
The scheme would be paid for <strong>by</strong> <strong>the</strong> introduction of a levy on suppliers of fossil fuels for heat,<br />
administered <strong>by</strong> Ofgem. Such suppliers largely supply gas currently, but it would also include suppliers of<br />
coal, heating oil and LPG. DECC currently expect <strong>the</strong> RHI <strong>to</strong> be in place April 2011.<br />
Renewables Obligation (RO)<br />
Entered in<strong>to</strong> force in April 2002<br />
Consultation on <strong>the</strong> Renewables Obligation Order 2009, published December 2008<br />
The Renewables Obligation aims <strong>to</strong> support and encourage <strong>the</strong> increasing adoption of renewable<br />
electricity in <strong>the</strong> UK. It requires licensed electricity suppliers <strong>to</strong> source a specific and annually increasing<br />
percentage of <strong>the</strong> electricity <strong>the</strong>y supply from renewable sources. The current level is 9.1% for 2008/09<br />
rising <strong>to</strong> 15.4% <strong>by</strong> 2015/16.<br />
A Renewables Obligation Certificate (ROC) is a green certificate issued <strong>to</strong> an accredited genera<strong>to</strong>r for<br />
eligible renewable electricity generated within <strong>the</strong> United Kingdom and supplied <strong>to</strong> cus<strong>to</strong>mers within <strong>the</strong><br />
United Kingdom <strong>by</strong> a licensed electricity supplier. Originally one ROC is issued for each megawatt hour<br />
(MWh) of eligible renewable output generated, but <strong>the</strong> update <strong>to</strong> this system in April 2009 introduced a<br />
banding. 159<br />
The targets for <strong>the</strong> RO are linked <strong>to</strong> <strong>the</strong> targets that <strong>the</strong> UK is committed <strong>to</strong> through <strong>the</strong> European Union’s<br />
Renewables Directive. This proposes that Member States adopt national targets for renewables that are<br />
consistent with reaching <strong>the</strong> overall EU target of 22.1% of electricity <strong>by</strong> 2010. The proposed UK share of<br />
this target is for 10% of electricity consumption <strong>to</strong> come from renewables eligible under <strong>the</strong> directive <strong>by</strong><br />
2010.<br />
To demonstrate that <strong>the</strong>y have met <strong>the</strong>ir share of <strong>the</strong> RO, suppliers must obtain certificates for renewable<br />
power supplied. These certificates (Renewable Obligation Certificates - ROCs, and SROCs in Scotland)<br />
are issued <strong>to</strong> genera<strong>to</strong>rs in accordance with <strong>the</strong> metered output of eligible renewable electricity <strong>the</strong>y have<br />
supplied. The certificates may be sold on <strong>to</strong> any supplier, with or without <strong>the</strong> electricity, and suppliers<br />
must redeem certificates with Ofgem (<strong>the</strong> Electricity and Gas Industries Regula<strong>to</strong>r) at <strong>the</strong> end of each 12<br />
month Obligation period <strong>to</strong> demonstrate <strong>the</strong>ir compliance with <strong>the</strong> obligation.<br />
Climate Change Levy (CCL)<br />
Entered in<strong>to</strong> force in April 2001<br />
The Climate Change Levy (CCL) 160 is a levy on non-domestic energy supply in <strong>the</strong> UK, which is offset <strong>by</strong><br />
a reduction in employer’s national insurance contributions. The CCL is under <strong>the</strong> management of <strong>the</strong><br />
HMRC. Accreditation is carried out via Ofgem.<br />
Under <strong>the</strong> CCL non-domestic electricity cus<strong>to</strong>mers are required <strong>to</strong> pay <strong>the</strong> levy as follows:<br />
• 0.47p/kWh for electricity,<br />
• 0.164p/kWh for gas,<br />
• 1.02p/kg (equivalent <strong>to</strong> 0.15p/kWh) for coal and<br />
159 Bioenergy Review for <strong>the</strong> Environment Agency, Draft Report, January 2009.<br />
160 For more information see <strong>the</strong> HMRC web site: http://cus<strong>to</strong>ms.hmrc.gov.uk/
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• 0.105p/kg (equivalent <strong>to</strong> 0.07p/kWh) for liquefied petroleum gas (LPG).<br />
The CCL has a number of exemptions, including fuels used <strong>by</strong> domestic users, fuels used <strong>by</strong> <strong>the</strong><br />
transport sec<strong>to</strong>r, fuels used for <strong>the</strong> generation of o<strong>the</strong>r forms of energy (e.g. electricity generation) or for<br />
non-energy generation (e.g. <strong>the</strong> use of “fuels” as carbon sources for o<strong>the</strong>r purposes, such as a reductant<br />
in metal smelting). In addition <strong>the</strong>re are various ways that <strong>the</strong> cost of <strong>the</strong> levy can be reduced. For<br />
example, <strong>the</strong>re is an 80% discount from <strong>the</strong> CCL for sec<strong>to</strong>rs that agree <strong>to</strong> targets for improving <strong>the</strong>ir<br />
energy efficiency or reducing carbon emissions <strong>by</strong> specified deadlines (“climate change agreements”<br />
(CCA)). 161<br />
There are various o<strong>the</strong>r exemptions but that most relevant <strong>to</strong> energy from waste is that electricity from<br />
renewable sources is exempted from <strong>the</strong> CCL. To qualify, suppliers of renewable electricity must obtain<br />
Renewables Levy Exemption Certificates (“Renewable LECs”). These are issued in respect of eligible<br />
renewable output and are used <strong>to</strong> prove that <strong>the</strong> electricity supplied is from renewable sources. 1 MWh<br />
of renewable power is equal <strong>to</strong> 1 LEC. If this supply is <strong>the</strong>n made <strong>to</strong> a non-domestic cus<strong>to</strong>mer it will not<br />
attract CCL payments. Guidance on <strong>the</strong> HMRC web site indicates that exempt renewable sources<br />
include municipal and industrial wastes and agricultural and forestry residues, as explained in Box 2<br />
Box 2 Rules for Levy Exemption certificates (LECs) for waste and biomass under <strong>the</strong> CCL<br />
LECS for waste fuelled generating stations<br />
The regulations allow for LECs <strong>to</strong> be granted for 50% of <strong>the</strong> electricity from power stations fuelled <strong>by</strong><br />
waste. If <strong>the</strong> opera<strong>to</strong>r considers that <strong>the</strong> proportion of renewable energy content of <strong>the</strong> waste is higher<br />
than 50% and he can provide sufficient evidence <strong>to</strong> Ofgem <strong>the</strong>n more than 50% may be claimed.<br />
LECs for Biomass power generation<br />
To claim LECs <strong>the</strong> biomass power station opera<strong>to</strong>rs must provide <strong>the</strong> following information <strong>to</strong> Ofgem:<br />
o The proposed % of biomass<br />
o Full details of <strong>the</strong> biomass content showing proportions of each category <strong>by</strong> weight<br />
o The CV (MJ/kg) of each category of feeds<strong>to</strong>ck, giving details of how this was obtained.<br />
o A description of facilities for s<strong>to</strong>ring biomass<br />
o Details of <strong>the</strong> supplier(s) of biomass, including names and addresses and a copy of<br />
extracts of contracts that detail <strong>the</strong> biomass content and contract duration.<br />
European Emissions Trading Scheme (EU ETS)<br />
Introduced in 2005<br />
1 st Trading period: January 2005 – December 2007<br />
2 nd Trading period: January 2008 – December 2012<br />
The EU ETS 162 is an EU wide scheme intended <strong>to</strong> help meet <strong>the</strong> EU’s GHG reduction targets under <strong>the</strong><br />
Kyo<strong>to</strong> Pro<strong>to</strong>col. The scheme creates a price for carbon through <strong>the</strong> establishment of a market for carbon<br />
emission reductions. The EU ETS is currently in its second phase, which runs from 2008-2012. The<br />
scheme operates through <strong>the</strong> allocation and trade of greenhouse gas emissions allowances throughout<br />
<strong>the</strong> EU – one allowance represents one <strong>to</strong>nne of carbon dioxide equivalent. A cap on <strong>the</strong> <strong>to</strong>tal amount of<br />
emissions allowed from all <strong>the</strong> installations covered is set <strong>by</strong> each Member State in <strong>the</strong>ir ‘national<br />
allocation plan’ or NAP. The allowances are <strong>the</strong>n distributed within Member States <strong>to</strong> <strong>the</strong> qualifying<br />
installations. In <strong>the</strong> UK, <strong>the</strong> ETS is implemented via UK Regulations that are regulated <strong>by</strong> <strong>the</strong><br />
Environment Agency for England and Wales, <strong>the</strong> Scottish Environment Protection Agency in Scotland<br />
and Department for <strong>the</strong> Environment and Heritage Services in Nor<strong>the</strong>rn Ireland.<br />
161<br />
These sec<strong>to</strong>rs are: aluminium, cement, ceramics, chemicals, food and drink, foundaries, glass, non-ferrous metals , paper, steel, and 20 or so<br />
smaller sec<strong>to</strong>rs.<br />
162<br />
For more information on <strong>the</strong> Eu ETS see <strong>the</strong> Defra web site: http://www.defra.gov.uk/environment/climatechange/trading/eu/index.htm and <strong>the</strong><br />
Environment Agency’s NatRegs site: http://www.netregs.gov.uk/netregs/62975.aspx<br />
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Currently <strong>the</strong> energy, iron and steel, mineral process and pulp and paper industries are covered <strong>by</strong> EU<br />
ETS. All installations carrying out activities in <strong>the</strong>se areas are required <strong>to</strong> hold a GHG emissions permit,<br />
which will require <strong>the</strong> installations <strong>to</strong> moni<strong>to</strong>r and <strong>report</strong> emissions in accordance with a plan that has<br />
been approved <strong>by</strong> <strong>the</strong> Regula<strong>to</strong>r.<br />
A site becomes liable under <strong>the</strong> EU ETS when <strong>the</strong> sum of <strong>the</strong> site’s rated combustion capacity exceeds<br />
20MW (<strong>the</strong>rmal). 163 Once over this limit <strong>the</strong> site’s CO2 emissions are capped and strict moni<strong>to</strong>ring is<br />
required. Emissions are required <strong>to</strong> stay within <strong>the</strong> cap or <strong>the</strong> site will need <strong>to</strong> trade carbon. Biomass or<br />
waste boilers are included <strong>to</strong>wards <strong>the</strong> <strong>to</strong>tal site limit. Therefore an opera<strong>to</strong>r cannot reduce <strong>the</strong> site’s<br />
generating capacity under EU ETS <strong>by</strong> substituting biomass or waste fuelled plant for fossil fuel plant.<br />
However, CO2 emissions from biomass are rated as zero under EU ETS, which means that any carbon<br />
emissions resulting from <strong>the</strong> biomass will not count <strong>to</strong>wards <strong>the</strong> site’s emissions. This may help a site<br />
meet its limit for GHG emissions and be able <strong>to</strong> trade any surplus.<br />
The relevance of this <strong>to</strong> waste for energy is that <strong>the</strong> biomass content of waste will also be rated as zero –<br />
and for high biomass wastes this is a considerable advantage, provided <strong>the</strong> biomass content can be<br />
easily demonstrated<br />
In addition a third phase, running from 2013, is in planning. One of <strong>the</strong> proposals under consideration is<br />
<strong>to</strong> set an emission target for sec<strong>to</strong>rs not covered <strong>by</strong> <strong>the</strong> current ETS (e.g. <strong>the</strong> buildings, transport and<br />
waste sec<strong>to</strong>rs). In addition <strong>the</strong> next phase may include o<strong>the</strong>r emissions as well as CO2.<br />
163 According <strong>to</strong> Defra’s guidance: ‘<strong>the</strong> EU ETS Directive expressly states that <strong>the</strong> burning of municipal waste and hazardous waste is not treated as a<br />
“combustion installation” for <strong>the</strong> purposes of <strong>the</strong> EU ETS. Where primary purpose of incineration is <strong>the</strong> provision of energy using a fuel derived from<br />
waste, <strong>the</strong>n <strong>the</strong> installation is a “combustion installation” under <strong>the</strong> medium definition.’
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7 Solid recovered fuels and o<strong>the</strong>r fuels<br />
manufactured from waste<br />
Each energy conversion technology is limited in <strong>the</strong> range of fuel types that it can accept and places<br />
demands on <strong>the</strong> preceding steps in <strong>the</strong> chain, in terms of fuel quality, properties and composition.<br />
Technologies are being introduced in <strong>the</strong> UK and elsewhere that transform waste components from <strong>the</strong>ir<br />
raw form <strong>to</strong> standard fuels with a defined specification. Manufactured fuels can offer <strong>the</strong> following<br />
benefits:<br />
• Consistent properties that can be defined and used in contracts making <strong>the</strong> material a tradable<br />
commodity.<br />
• Physical and biological stability that makes longer term s<strong>to</strong>rage possible and can even out<br />
unbalances between <strong>the</strong> constant supply of waste and <strong>the</strong> seasonal demand for energy.<br />
• An opportunity <strong>to</strong> manage <strong>the</strong> properties of <strong>the</strong> fuel <strong>to</strong> achieve optimum performance from <strong>the</strong><br />
energy technology.<br />
These fuels are in many ways <strong>the</strong> key <strong>to</strong> using waste in a diverse range of energy technologies that offer<br />
higher resource use efficiency and enhanced greenhouse gas reduction potential when compared <strong>to</strong><br />
traditional combustion with energy recovery. They allow CHP installations <strong>to</strong> be sized according <strong>to</strong> <strong>the</strong><br />
heat load and processes <strong>to</strong> manufacture transport fuels and methane <strong>to</strong> be operated at an economic<br />
scale.<br />
We have identified <strong>the</strong> following manufactured fuels on sale or planned in <strong>the</strong> UK.<br />
• Solid recovered fuels. These fuels are produced from mixed wastes from <strong>the</strong> municipal and<br />
commercial stream <strong>by</strong> separating <strong>the</strong> high heating value components from <strong>the</strong> residues remaining<br />
after conventional recycled products have been removed. The material contains both biological<br />
and non-biological matter. They are supplied dried and ei<strong>the</strong>r shredded for short distance and<br />
short term transport or compressed in<strong>to</strong> pellets for longer distances and s<strong>to</strong>rage times.<br />
• Graded waste wood fuels. This sec<strong>to</strong>r is growing rapidly as wood fired power plants are built <strong>to</strong><br />
take advantage of <strong>the</strong> reformed Renewables Obligation. Waste wood is collected from industry<br />
and amenity centres and graded depending on <strong>the</strong> level of contamination. The grades are <strong>the</strong>n<br />
chipped and sold <strong>to</strong> a specification.<br />
• Clean grade wood chips from virgin materials. Here wood residues for forestry and sawmills<br />
are chipped and potentially dried <strong>to</strong> meet a specification.<br />
• Domestic grade wood pellet fuel from saw mill <strong>by</strong>-product. Sawmill residues, in particular<br />
sawdust, is dried and compressed through a die in<strong>to</strong> small cylinders approximately 6mm in<br />
diameter and 10 mm long. This fuel resembles cattle feed or cat litter and is clean and free<br />
flowing. Several small scale combustion appliances have been developed <strong>to</strong> take advantage of<br />
<strong>the</strong> properties of this fuel. The high energy density means that it can be transported economically<br />
regionally, nationally, and internationally.<br />
• Industrial grade pellet from forestry, cereal processing residue and clean waste wood.<br />
This is similar <strong>to</strong> <strong>the</strong> domestic pellet but has a higher ash content and larger size.<br />
• Thermochemical fuels. These are chars and pyrolysis oils produced close <strong>to</strong> <strong>the</strong> point of<br />
arising. Supplied ei<strong>the</strong>r separately or as a slurry mix, <strong>the</strong> increased energy density extends <strong>the</strong><br />
economic transport distance for local <strong>to</strong> national. These fuels are not currently produced but<br />
have been proposed as a feeds<strong>to</strong>ck option for large gasification processes producing 2 nd<br />
generation biofuels or Substitute Natural Gas (SNG). We also include <strong>to</strong>rrefaction, or high<br />
temperature drying in this category.<br />
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7.1 Technologies for manufacturing fuels<br />
7.1.1 Mechanical / biological processing of MSW <strong>to</strong> Solid Recovered Fuel<br />
(SRF)<br />
C & I waste<br />
MSW<br />
Process Description<br />
Mechanical/biological treatment (MBT) encompasses a wide range of technologies aiming <strong>to</strong> process<br />
solid waste <strong>by</strong> a mixture of mechanical and biological separation. 164 It is not a new technology, and<br />
mechanical sorting and biological treatment processes have been used for many years in municipal<br />
waste management.<br />
MBT plants produce a solid recovered fuel (SRF) product from <strong>the</strong> drier, higher calorific value fractions of<br />
municipal and commercial waste. The first step is aerobic digestion, or fermentation, of solid organic<br />
material (composting) with <strong>the</strong> produced heat drying <strong>the</strong> waste. It is <strong>the</strong>n mechanically sorted <strong>to</strong> produce<br />
a fuel product that contains mainly paper and plastic. Additional fractions are produced that are suitable<br />
for recovery and recycling such as metal, glass and plastic, whilst <strong>the</strong> remaining waste is stabilised as a<br />
pre-treatment <strong>to</strong> landfill.<br />
Commercial status<br />
MBT is commercially available in most countries in <strong>the</strong> EU, and in <strong>the</strong> UK <strong>the</strong>re are a number of<br />
operational sites, <strong>the</strong>se are listed below.<br />
Table 48 Risks and barriers for MBT<br />
Level of Risk Comment<br />
Technical Low Operating commercial plant in existence.<br />
Established mature technologies.<br />
Social & Planning Medium Not as divisive as an incinera<strong>to</strong>r but still subject of<br />
concern as a waste technology. Waste transport<br />
is always a primary concern of residents in <strong>the</strong><br />
locality.<br />
Financial Medium Requires revenue from sale of fuel but market not<br />
well established.<br />
Fuel is still classed as a waste which may give<br />
problems with sale and use and hence price.<br />
Standards and agreed specifications are needed<br />
<strong>to</strong> make <strong>the</strong> fuel product a traded commodity.<br />
Regula<strong>to</strong>ry Medium Fuel is still classed as a waste which may give<br />
problems with sale and use and hence price.<br />
The legal status needs <strong>to</strong> be clarified. Standards<br />
would help <strong>to</strong> clarify definitions.<br />
Focusing on one site <strong>to</strong> give a detailed example of <strong>the</strong> processes used, <strong>the</strong> Frog Island site in east<br />
London is a recent development using <strong>the</strong> proprietary Ecodeco process. This process first shreds <strong>the</strong><br />
waste, <strong>the</strong>n dries it for up <strong>to</strong> 15 days using <strong>the</strong> heat from <strong>the</strong> composting biomass <strong>to</strong> reduce its moisture<br />
164 Mechanical Biological Treatment of Municipal Solid Waste. Prepared <strong>by</strong> Enviros Consulting Limited on behalf of Defra as part of <strong>the</strong> New<br />
Technologies Supporter Programme, 2007.<br />
Mechanical/Biological<br />
Treatment (MBT)<br />
SRF
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content. The dried waste is <strong>the</strong>n sorted, initially using screen separation, <strong>to</strong> produce a fuel product (about<br />
50% of <strong>the</strong> input weight, 15-18 MJ/kg), a metal product (which is recycled), and a residue product (which<br />
is landfilled). Equipment such as magnetic separa<strong>to</strong>rs and eddy current separa<strong>to</strong>rs are used <strong>to</strong> recover<br />
both ferrous and non-ferrous metal for recycling. Table 49 shows <strong>the</strong> typical mass balance for <strong>the</strong> biodrying<br />
process. Alternative methods are <strong>the</strong> Herhof Process, <strong>the</strong> 3R-UR process and <strong>the</strong> Draco Process.<br />
Table 49 Mass balance (Wt%) for bio-drying plants<br />
Fuel product<br />
Eco-deco %<br />
50<br />
Recyclables (metal) 5<br />
Process loss (water vapour from drying of input 25<br />
waste)<br />
Residue – glass/s<strong>to</strong>ne 165 and fines 20<br />
Total 100<br />
Figure 15 Frog Island Ecodeco plant<br />
The following examples of operationally active MBT sites in <strong>the</strong> UK contain a range of processes. The<br />
organic fraction is usually fur<strong>the</strong>r processed, frequently using AD or composting; recyclable materials<br />
such as metals are removed and recycled while materials such as glass may be recycled or may be<br />
ground and added <strong>to</strong> <strong>the</strong> organic compost like output (CLO) fraction.<br />
165 The glass/s<strong>to</strong>ne stream could be fur<strong>the</strong>r processed <strong>to</strong> produce a product suitable for recycling as an aggregate<br />
substitute.<br />
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Table 50 MBT Plants in <strong>the</strong> UK 166<br />
Name and Location Volume Operational<br />
Bursom Industrial Estate<br />
MBT plant in Leicester<br />
150,000 <strong>to</strong>nnes p.a.<br />
The organic fraction is processed<br />
with AD (at Wanlip, see later)<br />
2004<br />
New Earth Solutions in<br />
Poole, Dorset<br />
50,000 <strong>to</strong>nnes p.a.<br />
The organic fraction is<br />
composted, producing 9000<br />
<strong>to</strong>nnes/yr.<br />
2006<br />
Frog Island, Rainham,<br />
Shanks Group Plc, East<br />
180,000 <strong>to</strong>nnes p.a.<br />
2006<br />
London Waste Authority The material bio-dried before<br />
being biologically treated and<br />
sorted. After removal of glass,<br />
metals and aggregates <strong>the</strong><br />
remainder is used as SRF.<br />
Jenkins Lane, Newham,<br />
East London Waste<br />
180,000 <strong>to</strong>nnes p.a.<br />
2007<br />
Authority, Shanks Group The process requires bio-drying<br />
Plc<br />
before materials are refined for<br />
energy recovery.<br />
Earth Tech in S<strong>to</strong>rnoway,<br />
Western Isles<br />
21,000 <strong>to</strong>nnes p.a.,<br />
Uses AD for <strong>the</strong> source separated<br />
waste and composting for <strong>the</strong><br />
residual waste (see later)<br />
2006<br />
Civic Environmental<br />
Systems in<br />
37,000 <strong>to</strong>nnes p.a.<br />
2003<br />
Durham<br />
Commercial development scale<br />
Elling<strong>to</strong>n,<br />
40,000 <strong>to</strong>nnes p.a. of fine, pre- 2006<br />
Northumberland graded material<br />
Shanks Ecodeco plant in<br />
Dumfries and Galloway<br />
60,000 <strong>to</strong>nnes p.a. 2006<br />
At least six MBT plants are currently under construction or have planning permission al<strong>read</strong>y granted:<br />
• A site that will be operational within a few months is <strong>the</strong> 250,000 <strong>to</strong>nnes/yr site at Waterbeach in<br />
Cambridgeshire. Alongside this <strong>the</strong> composting capacity of <strong>the</strong> facility will double <strong>to</strong> 100,000<br />
<strong>to</strong>nnes/yr. 167<br />
• Two sites in Lancashire are under construction, one in Leyland near Pres<strong>to</strong>n, <strong>the</strong> o<strong>the</strong>r at<br />
Thorn<strong>to</strong>n near Blackpool. These will use <strong>the</strong> Global Technology (3R-UR) process and have a<br />
combined capacity of over 300,000 <strong>to</strong>nnes per annum of household waste.<br />
• Southwark MBT plant, intended <strong>to</strong> process 87,500 <strong>to</strong>nnes per annum and <strong>to</strong> be operational <strong>by</strong><br />
2011. The site will produce SRF (solid recovered fuel) <strong>to</strong> be burnt at <strong>the</strong> near<strong>by</strong> SELCHP EfW<br />
plant in Lewisham. 168<br />
• A site near Colchester, Essex has been granted permission for throughput of 250,000 <strong>to</strong>nnes per<br />
annum, with an attached AD plant capable of handling 50,000 <strong>to</strong>nnes/yr. 169<br />
166<br />
Mechanical Biological Treatment of Municipal Solid Waste, 2007, Defra Brief, http://www.defra.gov.uk/environment/waste/wip/newtech/pdf/mbt.pdf<br />
167<br />
ENDS Report, 389, June 2007, p.17,<br />
http://www.ends<strong>report</strong>.com/index.cfm?action=<strong>report</strong>.article&articleID=17363&q=MBT%20plants&boolean_mode=all<br />
168<br />
ENDS Report 397, Feb 2008, p.17,<br />
http://www.ends<strong>report</strong>.com/index.cfm?action=<strong>report</strong>.article&articleID=18636&q=MBT%20plants&boolean_mode=all
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• The potential Westbury MBT plant in Wiltshire has been given planning permission for a 45,000<br />
<strong>to</strong>nnes per annum site that is now due <strong>to</strong> open in 2011. 170<br />
• Bioessence have received planning permission for a 400,000 <strong>to</strong>nne per annum plant in<br />
Merseyside as a pre-treatment step for a pyrolysis/gasification technology <strong>to</strong> generate 40 MW of<br />
electricity. The plant is scheduled <strong>to</strong> start operating in 2011. 171<br />
Fur<strong>the</strong>r sites that are planned, but do not yet have planning permission are a plant in West Sussex that<br />
will use <strong>the</strong> Haase process, a plant in Norwich, Norfolk which would use <strong>the</strong> Dranco process and a plant<br />
in Manchester using <strong>the</strong> BTA process.<br />
In addition <strong>the</strong> INEOS Chlor incinera<strong>to</strong>r site discussed above plans <strong>to</strong> receive <strong>the</strong> 275,000 <strong>to</strong>nnes of<br />
stabilised fuel waste from five MBT and AD sites in Manchester. The contract was announced in January<br />
2007, and funding was secured April 2009. 172<br />
Internationally, MBT is a well established technology, with many operational facilities using a range of <strong>the</strong><br />
processes described above. Several of <strong>the</strong> larger scale ones are detailed below in Table 51. Some of<br />
<strong>the</strong> sites also convert this fuel <strong>to</strong> electricity on site.<br />
Table 51 Examples of best practice large scale international facilities that convert MSW in<strong>to</strong> SRF.<br />
City<br />
Year<br />
Capacity<br />
<strong>to</strong>nnes/yr<br />
Luebeck,<br />
173 2005 150,000<br />
Germany<br />
Corteolona,<br />
Italy 174<br />
Eastern<br />
Creek,<br />
Australia 175<br />
2004 60,000 9MW<br />
2004 175,000 176 1.5 MW<br />
Lauta,<br />
177 2004 225,000 20MW<br />
Germany<br />
Generation<br />
Capacity Comments<br />
1.9MW This site uses <strong>the</strong> Haase process <strong>to</strong> sort<br />
electricity, <strong>the</strong> waste in<strong>to</strong> SRF fuel, inerts,<br />
2.3MW recyclables and an organic rich fraction,<br />
heat which is processed fur<strong>the</strong>r using AD.<br />
This site is operated <strong>by</strong> Ecoenergia S.r.l.<br />
and uses <strong>the</strong> ‘Ecodeco’ process<br />
technology. The SRF produced is used<br />
<strong>to</strong> produce electricity.<br />
The facility is currently being expanded<br />
<strong>to</strong> 220,000 <strong>to</strong>nnes/annum. It utilises <strong>the</strong><br />
3R-UR process and produces three<br />
products; metals for recycling, a fuel<br />
product, and an organics rich product<br />
which is converted <strong>to</strong> compost like<br />
products onsite.<br />
This plant is part of <strong>the</strong> regional waste<br />
plan for Upper Lusatia, Lower Silesia<br />
(RAVON). The plant uses SRF derived<br />
from <strong>the</strong> local area.<br />
169 ENDS Report 393, Oc<strong>to</strong>ber 2007, p.20,<br />
http://www.ends<strong>report</strong>.com/index.cfm?action=<strong>report</strong>.article&articleID=17938&q=MBT%20plants&boolean_mode=all<br />
170 Wiltshire Approves Hills MBT Plant, 23 March 2009, LetsRecycle.com,<br />
http://www.letsrecycle.com/do/ecco.py/view_item?listid=37&listcatid=217&listitemid=31269<br />
171 Plan <strong>to</strong> develop 40MW gasification plant on Merseyside. News item at www.newenergyfocus.com, 28 January 2009.<br />
172 News item at Greater Manchester Waste Disposal Authority - http://www.gmwda.gov.uk/news.htm<br />
173 173 Visit <strong>by</strong> AEA staff <strong>to</strong> Luebeck Plant, June 2008<br />
174 Ecogergia, http://www.ecoenergia.it/ecoenergia_ing/its_termocorteolona.html<br />
175 Eastern Creek in Sydney – A member of AEA visited this plant in 2007<br />
176 Energent Capital, http://www.emergentcapital.com.au/globalrenewables/<br />
177 Lauta, http://www.industcards.com/wte-germany.htm<br />
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Utilising SRF in isolation for energy generation is not common in <strong>the</strong> UK. There are currently two sites<br />
that use this material. Slough Heat and Power in Berkshire is a CHP plant with a generating capacity of<br />
101MW. This site takes up <strong>to</strong> 100,000 <strong>to</strong>nnes of material each year – a combination of clean wood waste<br />
and SRF as one of its boiler systems is WID compliant. The second site at Alling<strong>to</strong>n, in Kent which takes<br />
500,000 <strong>to</strong>nnes per annum of minimally treated SRF <strong>to</strong> produce 43MW electricity from two large bubbling<br />
fluidised bed boilers. 178<br />
There are several industries where making use of SRF is al<strong>read</strong>y established, usually for <strong>the</strong> generation<br />
of heat. Cement kilns are one such industry, <strong>the</strong> paper industry is <strong>the</strong> o<strong>the</strong>r. 166 The British Cement<br />
Association <strong>report</strong>s that all but one of <strong>the</strong> 15 cement kilns in <strong>the</strong> UK use SRF.<br />
7.1.2 Mechanical / Heat Treatment of MSW <strong>to</strong> solid recovered fuel<br />
C & I waste<br />
MSW<br />
Mechanical Heat<br />
Treatment (MHT)<br />
Process Description<br />
Mechanical Heat Treatment (MHT) is a term that is used <strong>to</strong> describe configurations of mechanical and<br />
<strong>the</strong>rmal, including steam, based technologies. The purpose of <strong>the</strong>se processes is <strong>to</strong> separate a mixed<br />
waste stream in<strong>to</strong> several component parts, <strong>to</strong> give fur<strong>the</strong>r options for recycling, recovery and in some<br />
instances biological treatment. The processes also sanitises <strong>the</strong> waste <strong>by</strong> destroying bacteria. The basic<br />
flowchart for a Mechanical Heat Treatment process 179 is shown below in Figure 16.<br />
SRF<br />
Figure 16 Flowchart representing Mechanical Heat Treatment<br />
178 http://www.kentenviropower.co.uk/default.asp<br />
179 A description of MHT processes can be found in “Mechanical Heat Treatment of Municipal Solid Waste”, published <strong>by</strong> Defra in 2007.
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The most common system being promoted for <strong>the</strong> treatment of MSW using MHT is based around a<br />
<strong>the</strong>rmal au<strong>to</strong>clave. The development for use with MSW started in <strong>the</strong> early 1990’s, and a number of<br />
patents have been issued.<br />
A second type of MHT system is a non-pressurised heat treatment process, where waste is mixed <strong>to</strong> a<br />
slurry with water and <strong>the</strong>n heated in a rotating kiln prior <strong>to</strong> mechanical separation. This process requires<br />
a pre-treatment stage, which includes <strong>the</strong> use of a shredder.<br />
Both <strong>the</strong> au<strong>to</strong>clave process and <strong>the</strong> non-pressurised treatment processes have <strong>the</strong> following effect on <strong>the</strong><br />
waste:<br />
• Biodegradable materials, including paper and card, are broken down in<strong>to</strong> a high biomass fibre for<br />
which <strong>the</strong> main use is as a fuel product;<br />
• Glass bottles and tins have <strong>the</strong>ir labels removed as <strong>the</strong> glue disintegrates under <strong>the</strong> action of <strong>the</strong><br />
heat;<br />
• Plastics are softened, and labels are removed. Certain types of plastics are deformed <strong>by</strong> <strong>the</strong> heat,<br />
but remain in a recognisable state, whereas o<strong>the</strong>r plastics soften completely forming hard balls of<br />
dense plastic.<br />
Both processes produce product streams (fibre product, plastic, etc) using well-established mechanical<br />
processing techniques (screening, density separation, magnetic separation, eddy current separation).<br />
The resulting outputs are relatively clean ‘hard’ recyclables (tins, glass and plastics with no labels and<br />
most of <strong>the</strong> food waste removed) a fibrous material from <strong>the</strong> breakdown of paper, card and green/kitchen<br />
waste constituents, and a reject fraction.<br />
Both systems heat <strong>the</strong> waste <strong>to</strong> temperatures in <strong>the</strong> range of 120-170°C, which is sufficient <strong>to</strong> destroy<br />
bacteria present in <strong>the</strong> waste. This has benefits in terms of s<strong>to</strong>rage, transport and handling of <strong>the</strong> outputs<br />
as <strong>the</strong>y are sanitised, and are free from <strong>the</strong> biological activity that may give rise <strong>to</strong> odour problems. There<br />
is also a significant volume reduction in <strong>the</strong> waste.<br />
Table 52 shows <strong>the</strong> typical specification of a mechanical heat treatment plant. About 15-20% of <strong>the</strong> input<br />
waste is landfilled.<br />
Table 52: Typical specification of a mechanical heat treatment process<br />
Product stream Wt % of input MSW<br />
Fibre product 60-65<br />
Metal products 4-5<br />
Mixed plastic product 7-12<br />
Aggregate substitute product 4-8<br />
Landfilled 180 15-20<br />
Total 100<br />
O<strong>the</strong>r products from <strong>the</strong> process<br />
Suppliers of MHT plants claim that <strong>the</strong>se plants can recycle up <strong>to</strong> 20% of <strong>the</strong> input waste. However, whilst<br />
established markets for <strong>the</strong> metal products are available, <strong>the</strong> <strong>to</strong>tal level of recycling achieved will depend<br />
on <strong>the</strong> availability of markets for both <strong>the</strong> mixed plastic product and <strong>the</strong> aggregate substitute product. If<br />
<strong>the</strong>se markets are not available <strong>the</strong>n <strong>the</strong>se products will be landfilled.<br />
Commercial status<br />
Some demonstration projects are operating under <strong>the</strong> Defra Waste Innovation Programme, such as <strong>the</strong><br />
Huy<strong>to</strong>n MHT site in Merseyside.<br />
180 The landfilled reject stream is mainly o<strong>the</strong>r combustible materials.<br />
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Table 53 Risks and barriers for MHT<br />
Level of Risk Comment<br />
Technical High Demonstration projects only at present.<br />
Social & Planning Medium Not as divisive as an incinera<strong>to</strong>r but still subject of<br />
concern as a waste technology.<br />
Financial Medium Requires revenue from sale of fuel but market not<br />
well established.<br />
Fuel is still classed as a waste which may give<br />
problems with sale and use and hence price.<br />
Standards and agreed specifications are needed<br />
<strong>to</strong> make <strong>the</strong> fuel product a traded commodity.<br />
Regula<strong>to</strong>ry Medium Fuel is still classed as a waste which may give<br />
problems with sale and use hence a reduced<br />
price.<br />
The legal status needs <strong>to</strong> be clarified. Standards<br />
would help <strong>to</strong> clarify definitions.<br />
There are a number of suppliers of au<strong>to</strong>clave based MHT technology in <strong>the</strong> UK. Sterecycle 181 have<br />
constructed a 100,000 <strong>to</strong>nnes per annum au<strong>to</strong>clave facility at Ro<strong>the</strong>rham, which is currently treating<br />
residual MSW from three local authorities and has received planning approval <strong>to</strong> double <strong>the</strong> capacity <strong>to</strong><br />
200,000 <strong>to</strong>nnes per annum. 182<br />
The Huy<strong>to</strong>n MHT site in Merseyside uses a Mechanical Heat Treatment technology developed <strong>by</strong> Orchid<br />
Environmental, designed <strong>to</strong> process 80,000 <strong>to</strong>nnes/yr of MSW. 183 The site, which began operation in<br />
June 2008 as a demonstration plant, uses a low heat process, <strong>to</strong>ge<strong>the</strong>r with air and moisture <strong>to</strong> separate<br />
waste and convert <strong>the</strong> organic fraction in<strong>to</strong> fuel pellets. This site is part of <strong>the</strong> DEFRA Demonstra<strong>to</strong>r<br />
Programme, but suffered a fire in 2008. The pre-treated waste is mixed with water, and this is <strong>the</strong>n fed<br />
in<strong>to</strong> a drum, which is heated using hot air.<br />
Graphite Resources obtained planning approval in 2005 for an au<strong>to</strong>clave plant at <strong>the</strong> Derwenthaugh<br />
(Gateshead) Eco-Parc, which will process 300,000 <strong>to</strong>nnes per annum of mainly commercial waste. Plant<br />
construction was delayed due <strong>to</strong> financing issues, but <strong>the</strong> plant is now being constructed, and is<br />
scheduled <strong>to</strong> begin operating in <strong>the</strong> autumn of 2009. 184<br />
Planning permission was received <strong>by</strong> Estech (now part of VT group) for a plant in Herefordshire in 2004,<br />
but construction was delayed when <strong>the</strong> planning approval was challenged, and whilst this has now been<br />
resolved, <strong>the</strong> plant is unlikely <strong>to</strong> be operational until 2012. VT group have received planning permission<br />
for a 100,000 <strong>to</strong>nne per annum au<strong>to</strong>clave in Wakefield as part of a waste treatment site which will also<br />
include an anaerobic digestion facility, and hope <strong>to</strong> secure financial close for this project during 2009. 185<br />
Orchid Environmental have received planning permission from Flintshire county council <strong>to</strong> build a 160,000<br />
<strong>to</strong>nne-a-year capacity mechanical heat treatment facility at Flintshire, Deeside. 186 This site would aim <strong>to</strong><br />
mainly treat commercial and industrial waste, and has plans <strong>to</strong> develop up <strong>to</strong> six similar projects over <strong>the</strong><br />
next two years.<br />
181<br />
http://www.sterecycle.com/<br />
182<br />
Yorkshire au<strong>to</strong>clave plant <strong>to</strong> double capacity. News item at www.letsrecycle.com, 20 January 2009<br />
183<br />
Defra Factsheet, Merseyside WDA/Orchid Environmental, http://www.defra.gov.uk/environment/waste/wip/newtech/dem-programme/pdf/MWDA.pdf<br />
184<br />
Information at www.graphiteresources.com<br />
185<br />
VT Group wins planning go-ahead for Wakefield PFI. News item at www.letsrecycle.com, 28 November 2008.<br />
186<br />
Green Light for £20 million Flintshire MHT plant. News item at letsrecycle.com, 15 December 2008
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7.1.3 Standards for Solid Recovered fuels<br />
There is considerable pressure for solid recovered fuels from MBT and MHT treatment plant <strong>to</strong> be<br />
regarded as products ra<strong>the</strong>r than waste. This has resulted in <strong>the</strong> setting up of a CEN Technical<br />
committee <strong>to</strong> develop a suite of standards for <strong>the</strong> characterisation and analysis of <strong>the</strong>se products -<br />
TC343. The Work Programme for TC 343 is allocated <strong>to</strong> 5 Working Groups:<br />
• WG1 Terminology and Quality Assurance<br />
• WG2 Fuel specifications and classes<br />
• WG3 Sampling, sample reduction and supplementary test methods<br />
• WG4 Physical/Mechanical tests<br />
• WG5 Chemical Tests<br />
The mandate for this standardisation work is given as: -<br />
“fuels prepared from non-hazardous waste <strong>to</strong> be utilised for energy recovery in waste incineration or coincineration<br />
plants regulated under Community environmental legislation”.<br />
The current status is that all Technical Specifications for CEN 343 have now been submitted <strong>to</strong> formal vote and<br />
are expected <strong>to</strong> be come in<strong>to</strong> use as <strong>full</strong> standards in 2011.<br />
7.1.4 Preparation of wood chips and pellets<br />
Wood from forestry operations<br />
Wood fuel currently comes mostly from thinning operations where small diameter trees are felled, and<br />
even smaller diameter branches and material from <strong>the</strong> harvesting of timber logs that is <strong>to</strong>o small <strong>to</strong> be a<br />
primary product. These are chipped ei<strong>the</strong>r as part of <strong>the</strong> harvest operation or are taken <strong>to</strong> <strong>the</strong> roadside<br />
for chipping, or for delivery as small round-wood logs for chipping at <strong>the</strong> users facility.<br />
The latest installations under <strong>the</strong> Bioenergy Capital Grant Scheme have shown a marked preference for<br />
logs as <strong>the</strong>y s<strong>to</strong>re without degradation for a long period, and so can be regarded as a good strategic<br />
reserve, and provide a guaranteed clean fuel with no debris.<br />
Branch wood and <strong>to</strong>ps, so called brash, could be used as fuel but contains a higher proportion of ash,<br />
needles and debris and so is currently not extracted in any quantity. As demand increases <strong>the</strong>n this<br />
situation may change, but use of brash would likely require some engineering modifications <strong>to</strong> boilers <strong>to</strong><br />
cope with <strong>the</strong> increased ash.<br />
For smaller installations <strong>the</strong> quality of chip in terms of its size and moisture is critical <strong>to</strong> <strong>the</strong> reliable<br />
operation of <strong>the</strong> unit. The type of chipper used and <strong>the</strong> way in which <strong>the</strong> material is s<strong>to</strong>red plays an<br />
important part in guaranteeing good quality feeds<strong>to</strong>ck. Drum chippers produce <strong>the</strong> best quality and cut<br />
chip product should be s<strong>to</strong>red under cover.<br />
Pellet production from sawmill <strong>by</strong>-product<br />
Sawmills generate large quantities of sawdust that can be converted in <strong>to</strong> pellet fuel. Pellets are small<br />
cylinders of compressed wood manufactured in <strong>the</strong> same type of machine as cattle feed and cat litter.<br />
They are free flowing clean and convenient <strong>to</strong> use. Over <strong>the</strong> past decade clean wood pellets have<br />
transformed <strong>the</strong> small scale wood heating market with a range of boilers and room heaters designed<br />
specifically for pellets.<br />
The best example of pellet production is <strong>the</strong> Balcas Sawmill in Nor<strong>the</strong>rn Ireland. This installation was<br />
built with grant aid from <strong>the</strong> Bioenergy Capital Grant Scheme, and comprises a 2.7 MWe CHP installation.<br />
The fuel for <strong>the</strong> CHP is taken from <strong>the</strong> poor quality bark and slab wood whilst <strong>the</strong> sawdust is dried using<br />
<strong>the</strong> heat rejected from <strong>the</strong> steam cycle. The dry sawdust is compressed in <strong>to</strong> pellets at <strong>the</strong> rate of 40,000<br />
<strong>to</strong>nnes per annum. An additional installation is being built <strong>by</strong> Balcas in Scotland that will deliver 100,000<br />
<strong>to</strong>nnes of pellets per annum.<br />
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Through <strong>the</strong> Balcas project several thousand homes and businesses in Ireland have converted <strong>to</strong> wood<br />
pellet heating, also facilitated <strong>by</strong> energy grants available from Sustainable Energy Ireland.<br />
Experience from Austria suggests that wherever pellets are introduced <strong>the</strong>y result in an increased uptake<br />
of wood heating and dominate <strong>the</strong> small boiler market.<br />
Graded waste wood chip<br />
Following <strong>the</strong> building of <strong>the</strong> two major power projects at Lockerbie and Wil<strong>to</strong>n a market has grown <strong>to</strong><br />
supply waste wood in chipped form <strong>to</strong> an accepted quality standard. In both cases wood recycling<br />
companies have set up dedicated reception and sorting centres at <strong>the</strong> power plant. In <strong>the</strong>se centres <strong>the</strong><br />
wood is sorted <strong>to</strong> remove contaminated material, shredded and chipped <strong>to</strong> a size distribution set <strong>by</strong> <strong>the</strong><br />
power plant owner.<br />
The above examples deal with virgin wood, that has not undergone any treatment. Use of waste wood is<br />
more challenging as it will likely have been chemically treated with preservatives, and so can only be<br />
used in WID compliant plants. We understand that E.ON have plans <strong>the</strong> build five power plant each<br />
25MWe fuelled <strong>by</strong> waste wood. 187<br />
The recycled wood industry is growing rapidly as pressure <strong>to</strong> remove organic material from waste streams<br />
increases at <strong>the</strong> same time as <strong>the</strong> demand for renewable fuels. 188 Opera<strong>to</strong>rs are becoming more<br />
experienced and are able <strong>to</strong> supply a range of fuel specifications depending on <strong>the</strong> degree of<br />
contamination and source. 189<br />
7.1.5 Standards for wood based fuels<br />
The rapid growth of biomass energy applications in Europe and <strong>the</strong> increases projected as a result of <strong>the</strong><br />
Renewable Energy Directive have created a need for a suite of standards for <strong>the</strong> characterisation and<br />
analysis of wood fuels. These have been developed on an accelerated timetable <strong>by</strong> CEN Technical<br />
Committee 355. The remit for this group <strong>to</strong> develop standards for all forms of solid biofuels in Europe,<br />
including wood chips, wood pellets, briquettes, logs, sawdust and straw bales.<br />
These standards allow all relevant properties of <strong>the</strong> fuel <strong>to</strong> be described, and include both normative information<br />
that must be provided about <strong>the</strong> fuel, and informative information that can be included but is not required. As well<br />
as <strong>the</strong> physical and chemical characteristics of <strong>the</strong> fuel as it is, CEN 335 also provides information on <strong>the</strong> source<br />
of <strong>the</strong> material.<br />
The Work Programme for TC 335 contains 30 Work Items, which are allocated <strong>to</strong> 5 Working Groups (WGs):<br />
• WG 1 Terminology, descriptions and definitions<br />
• WG 2 Fuel specifications, classes and quality assurance<br />
• WG 3 sampling and sample preparation<br />
• WG 4 Physical and mechanical test methods<br />
• WG 5 Chemical test methods<br />
All Technical Specifications for CEN 335 have now been published.<br />
CEN 335 includes solid biofuels originating from <strong>the</strong> following sources:<br />
• Products from agriculture and forestry;<br />
• Vegetable waste from agriculture and forestry;<br />
• Vegetable waste from <strong>the</strong> food processing industry;<br />
187 http://pressreleases.eon-uk.com/blogs/eonukpressreleases/archive/2008/07/15/1257.aspx<br />
188 Wood Recyclers Association, www.woodrecyclers.org<br />
189 http://www.woodrecyclers.org/
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• Wood waste, with <strong>the</strong> exception of wood waste which may contain halogenated organic compounds or<br />
heavy metals as a result of treatment with wood preservatives or coating, and which includes in<br />
particular such wood waste originated from construction and demolition waste;<br />
• Continued-fibrous vegetable waste from virgin pulp production and from production of paper from pulp, if<br />
it is co-incinerated at <strong>the</strong> place of production and heat generated is recovered;<br />
• Cork waste.<br />
Draft standards for CEN 355 are available for download from <strong>the</strong> Biomass Information Centre website. 190<br />
Germany is somewhat ahead of <strong>the</strong> UK in its use of waste wood for energy and has developed a grading system<br />
based on composition and origin. 191 This has gained some acceptance in <strong>the</strong> UK because of its practical nature.<br />
It is given below.<br />
Box 3: German Waste Wood Grading System<br />
Waste wood category A I:<br />
Waste wood in its natural state or only mechanically worked with, during use, was at<br />
most insignificantly contaminated with substances harmful <strong>to</strong> wood.<br />
Waste wood category AII:<br />
Bonded, painted, coated, lacquered or o<strong>the</strong>rwise treated waste wood with no<br />
halogenated organic compounds in <strong>the</strong> coating and no wood preservative.<br />
Waste wood category A III:<br />
Waste wood with halogenated organic compounds in <strong>the</strong> coating, with no wood<br />
preservatives.<br />
Waste wood category A IV:<br />
Waste wood treated with wood preservatives, such as railway sleepers, telephone masts,<br />
hop poles, vine poles as well as o<strong>the</strong>r waste wood which, due <strong>to</strong> its contamination,<br />
cannot be assigned <strong>to</strong> waste wood categories A I, A II or A III, with <strong>the</strong> exception of<br />
waste wood containing PCBs.<br />
Category A I includes sawmill co-products which also currently have a market in <strong>the</strong> UK as fuel for cofiring<br />
at coal power plants, fuel for o<strong>the</strong>r stand-alone biomass plants and raw material for a variety of<br />
competing markets, including animal bedding, horticultural use and, most significantly, <strong>the</strong> panel board<br />
mills. Sawmill co-product that has only been mechanically treated is treated as clean wood for <strong>the</strong><br />
purposes of combustion under <strong>the</strong> Waste Incineration Directive (WID). It is transported long distances<br />
across <strong>the</strong> UK and is priced competitively compared <strong>to</strong> virgin biomass fuels.<br />
Category A II includes residues from <strong>the</strong> production of furniture, kitchens etc. This product is usually<br />
disposed of <strong>to</strong> landfill or mass burn incineration at present. It is difficult <strong>to</strong> separate out <strong>the</strong> clean waste<br />
wood from <strong>the</strong> contaminated and E.ON, for example, would have <strong>to</strong> take it unsorted. This product should<br />
not come within <strong>the</strong> WID. However, it is impossible <strong>to</strong> protect it from contamination with fractions of waste<br />
that do come under WID and <strong>the</strong>refore <strong>the</strong> position is not clear cut. It is likely that <strong>the</strong> Environment<br />
Agency would regard <strong>the</strong> potential contamination issue as important and class any combustion process<br />
under WID.<br />
Category A III is treated as waste for <strong>the</strong> purposes of combustion under WID and any plant burning <strong>the</strong>se<br />
wastes would need <strong>to</strong> comply with WID as part of <strong>the</strong> conditions of its licence.<br />
190 http://www.biomassenergycentre.org.uk<br />
191 Ordinance on <strong>the</strong> Management of Waste Wood dated 15 August 2002<br />
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Table 54 Risks and barriers for wood fuel production<br />
Level of Risk Comment<br />
Technical Low Many projects for both pellet and chip worldwide.<br />
Social & Planning Medium Some current waste wood installations can be<br />
unsightly and “bad neighbours” creating noise<br />
dust and fire risks from large quantities of s<strong>to</strong>red<br />
waste wood.<br />
Sawmill based installations are positive due <strong>to</strong><br />
reduced transport of residue, job creation and<br />
low additional impact.<br />
Financial Medium Requires revenue from sale of fuel but market<br />
not well established.<br />
Waste wood derived fuel is still classed as a<br />
waste which may give problems with sale and<br />
use and hence price.<br />
Standards and agreed specifications are needed<br />
<strong>to</strong> make <strong>the</strong> fuel product a traded commodity.<br />
Attractiveness depends on <strong>the</strong> price of oil as well<br />
as incentives.<br />
These aspects should be resolved within <strong>the</strong><br />
next few years.<br />
Regula<strong>to</strong>ry Medium Waste wood derived fuel is still classed as a<br />
waste which may give problems with sale and<br />
use hence a reduced price.<br />
The legal status needs <strong>to</strong> be clarified. Standards<br />
would help <strong>to</strong> clarify definitions.<br />
Market depends upon incentives for heat and<br />
electricity <strong>the</strong>se can change due <strong>to</strong> extraneous<br />
fac<strong>to</strong>rs.<br />
These aspects should be resolved within <strong>the</strong><br />
next few years.<br />
7.1.6 Thermochemical fuels<br />
The purpose of <strong>the</strong>rmochemical processes is <strong>to</strong> produce a fuel with an increased energy density and<br />
physical and chemical properties that are both more consistent than <strong>the</strong> source material, and better<br />
matched <strong>to</strong> <strong>the</strong> requirements of <strong>the</strong> conversion technology.<br />
The fuels in this category are derived from lignocellulosic materials such as wood, crop residues, paper<br />
and board. The two main categories are<br />
Char, Oils and liquors from pyrolysis ei<strong>the</strong>r as separate liquid and char products or slurry of <strong>the</strong> two.<br />
Char is similar <strong>to</strong> coal in some respects being friable and having a relatively high calorific value,<br />
unfortunately it contains less than half of <strong>the</strong> energy value of <strong>the</strong> source material. Pyrolysis liquids are a<br />
mixture of complex carbohydrates and hydrocarbons that contain up <strong>to</strong> 70% of <strong>the</strong> energy of <strong>the</strong> source<br />
material. The relative proportions of char and liquids depend upon <strong>the</strong> reaction conditions in <strong>the</strong> process.<br />
Torrefied material. Torrefaction is <strong>the</strong> heat treatment of <strong>the</strong> material at temperatures between 200°C<br />
and 300°C that results in <strong>the</strong> removal of all moisture and a subsequent degradation and shrinkage of <strong>the</strong><br />
polymeric structure of <strong>the</strong> material. The changes produced <strong>by</strong> this process give an end product that is<br />
more energy dense, friable and less susceptible <strong>to</strong> take up moisture from its environment. These<br />
changes make it easier <strong>to</strong> transport, s<strong>to</strong>re and <strong>to</strong> use, particularly when pelletised. Torrefaction has <strong>the</strong><br />
advantage of producing a consistent fuel that retains over 90% of <strong>the</strong> energy of <strong>the</strong> source material.
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More information, such as <strong>the</strong> principles and <strong>the</strong> mass and energy balances for this route are given in<br />
references 179 and 180. 192,193<br />
At present <strong>the</strong>se fuels have only been proposed, none are currently produced from waste materials<br />
specifically as fuels, o<strong>the</strong>r than in research and development activities.<br />
Producing fuels with improved properties has benefits in terms of transport s<strong>to</strong>rage and use but <strong>the</strong>re is a<br />
penalty in resource use efficiency due <strong>to</strong> <strong>the</strong> heat used for <strong>the</strong> processing. Uslu et al have analysed <strong>the</strong><br />
efficiency of a range of supply chains using <strong>the</strong>rmochemical fuels and pellets manufactured from wood<br />
and come <strong>to</strong> <strong>the</strong> conclusion that <strong>to</strong>rrefaction with an energy efficiency of 94% required least energy whilst<br />
pyrolysis fuels with an efficiency of 64% are unlikely <strong>to</strong> be cost effective. 194 This analysis was carried out<br />
largely on wood feeds<strong>to</strong>cks and was targeted at life cycles involving long distance transport but<br />
none<strong>the</strong>less <strong>the</strong> broad principle should hold for most lignocellulosic materials. These conclusions were<br />
confirmed <strong>to</strong> some extent <strong>by</strong> Mortimer who found that <strong>the</strong>re was no advantage in using pyrolysis based or<br />
o<strong>the</strong>r upgraded fuels in <strong>the</strong> supply <strong>to</strong> a transport biofuels plant in <strong>the</strong> North East. 195<br />
7.1.7 Conclusions for Solid Recovered Fuels<br />
Producing a fuel type that provides consistent properties will enable more waste <strong>to</strong> be utilised as a fuel<br />
source for <strong>the</strong> generation of energy or fuels. The status of this area in <strong>the</strong> UK is:<br />
• Processes are commercially available for producing fuels from MSW and C&I waste using <strong>the</strong><br />
heat from composting as <strong>the</strong> energy from drying.<br />
• Processes for <strong>the</strong> production of fuels using <strong>the</strong>rmal energy <strong>to</strong> dry and sterilise waste are currently<br />
being demonstrated and may offer advantages in providing a more consistent product that is<br />
biologically stable.<br />
• Standards for fuels derived from MSW have been developed but are not widely used<br />
• The production of graded wood waste fuels has expanded rapidly in <strong>the</strong> last three years.<br />
Standards and codes are being adopted <strong>by</strong> <strong>the</strong> industry which is aiding acceptance and<br />
development.<br />
• Clean wood fuels are becoming widesp<strong>read</strong> and standards and codes are being adopted <strong>by</strong> <strong>the</strong><br />
industry.<br />
• Fuels prepared using pyrolysis and <strong>to</strong>rrefaction have been proposed but as yet not implemented<br />
commercially.<br />
192 Harold Boerrigter, Jaap Kiel, Patrick Bergman Proceedings of Thermalnet meeting April 2006 Lille<br />
http://www.<strong>the</strong>rmalnet.co.uk/docs/ECN_%20Torrefaction%20of%20Biomass%20as%20pretreatmentLille.pdf<br />
193 Report reference ECN-RX--05-180, Torrefaction for biomass upgrading, Patrick C.A. Bergman, Jacob H.A. Kiel<br />
Published at 14th European Biomass Conference & Exhibition,Paris, France, 17-21 Oc<strong>to</strong>ber 2005<br />
http://www.techtp.com/recent%20papers/ECN-Torrefaction%20for%20biomas%20upgrading%20-2005.pdf<br />
194 A. Uslu et al. / Energy 33 (2008) 1206–1223<br />
195 NNFCC project 09/016. Feb 2009<br />
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8 Supplying Energy from Waste <strong>by</strong><br />
Combustion<br />
In most European countries, <strong>by</strong> far <strong>the</strong> most common method of extracting energy from solid waste ei<strong>the</strong>r<br />
in untreated form or as a prepared fuel is combustion (or incineration) with energy recovery. Virtually all<br />
wastes can be treated <strong>by</strong> combustion and <strong>the</strong> technology is usually regarded as <strong>the</strong> default against which<br />
o<strong>the</strong>r options are measured.<br />
Combustion is a well established technology and <strong>the</strong> main technical challenges have been addressed.<br />
There remains however significant technical uncertainty surrounding <strong>the</strong> impact of <strong>the</strong> composition of <strong>the</strong><br />
waste on <strong>the</strong> performance of <strong>the</strong> heat exchange surfaces, particularly fouling and corrosion.<br />
O<strong>the</strong>r barriers remain, such as <strong>the</strong> largely negative public perception of such sites in some countries,<br />
including <strong>the</strong> UK.<br />
8.1 Process Description<br />
Untreated Waste<br />
Waste derived fuel<br />
Combustion<br />
Heat and/or<br />
Electricity<br />
Process Description<br />
A combustion system in its simplest form comprises two basic elements: a furnace where <strong>the</strong> fuel is<br />
burned and a boiler that recovers <strong>the</strong> heat from <strong>the</strong> combustion as steam or hot water.<br />
When <strong>the</strong> fuel enters <strong>the</strong> high temperature environment in a furnace it will first dry and <strong>the</strong>n decompose,<br />
or pyrolyse, in<strong>to</strong> volatile tars and gases and char components. These components <strong>the</strong>n react with air <strong>to</strong><br />
release <strong>the</strong> energy contained in <strong>the</strong> heating value of <strong>the</strong> fuel. This energy is released as radiation <strong>to</strong> <strong>the</strong><br />
walls of <strong>the</strong> furnace and in<strong>to</strong> a flow of hot flue gases <strong>to</strong> be captured <strong>by</strong> heat exchange surface in <strong>the</strong><br />
boiler that generates steam for use ei<strong>the</strong>r in <strong>the</strong> process, or <strong>by</strong> a turbine <strong>to</strong> produce electricity, or both<br />
(CHP).<br />
A furnace essentially consists of a box, lined ei<strong>the</strong>r with refrac<strong>to</strong>ry or water tubes, and a burner where <strong>the</strong><br />
air and fuel mix and burn. There are two main categories of burner for solid waste and biomass<br />
applications, grate and fluidised bed. The first has evolved from designs that have been used widely<br />
throughout <strong>the</strong> 19 th and 20 th centuries whilst <strong>the</strong> second is a fairly recent innovation from 1970’s onwards.<br />
Grate burners<br />
In grate-firing <strong>the</strong> fuel burns in a layer on a grid. Air for combustion is blown both through <strong>the</strong> grid and<br />
over <strong>the</strong> <strong>to</strong>p of <strong>the</strong> fuel layer. The processes of drying, pyrolysis and combustion of <strong>the</strong> volatiles and char<br />
take place sequentially as <strong>the</strong> material proceeds through <strong>the</strong> boiler on <strong>the</strong> grate. Various types of grids or<br />
grates have evolved <strong>to</strong> move <strong>the</strong> fuel through <strong>the</strong> boiler and eventually remove <strong>the</strong> ash. Some grates<br />
vibrate, some move slowly forward on chains whilst o<strong>the</strong>rs have a reciprocating action. Grates are<br />
reliable, but are considered somewhat inflexible and are designed <strong>to</strong> cope with a limited range of fuels.<br />
Experience in <strong>the</strong> UK has shown that high, and variable, moisture content fuels such as poultry litter can<br />
lead <strong>to</strong> uneven combustion and high dust emissions.
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Small industrial-commercial and domestic boilers are small grate burners that burn almost exclusively<br />
clean wood in <strong>the</strong> form of logs, chips and pellets. Logs are used mostly for domestic applications, pellets<br />
for domestic and commercial and chips for commercial <strong>to</strong> large commercial and industrial.<br />
Fluidised bed burners<br />
In a fluidised bed furnace, <strong>the</strong> fuel burns in a bed of sand or o<strong>the</strong>r mineral that is violently agitated <strong>by</strong> <strong>the</strong><br />
combustion air. The fuel is fed at a controlled rate <strong>to</strong> keep <strong>the</strong> temperature of <strong>the</strong> sand bed at 800 <strong>to</strong><br />
900°C. With moderate air velocities <strong>the</strong> bed has <strong>the</strong> appearance of a boiling liquid, hence <strong>the</strong> name<br />
bubbling fluidised bed (BFB). If a higher velocity is used <strong>the</strong> sand will be carried out of <strong>the</strong> furnace and<br />
must be recycled <strong>to</strong> <strong>the</strong> base via a cyclone – this is known as a circulating fluidised bed (CFB). Heat is<br />
removed and steam is raised <strong>by</strong> tubes in <strong>the</strong> bed of sand (not needed for biomass fuels), <strong>the</strong> walls of <strong>the</strong><br />
furnace and in <strong>the</strong> exhaust flue. This type of boiler is proving very popular for medium <strong>to</strong> large industrial<br />
boilers for coal and o<strong>the</strong>r solid fuels and is taking an increasing share of this market.<br />
A great advantage of <strong>the</strong> fluidised bed <strong>to</strong> <strong>the</strong> power plant opera<strong>to</strong>r is its fuel flexibility. This feature has<br />
been used <strong>to</strong> great advantage <strong>by</strong> CHP plants in <strong>the</strong> Nordic Countries, where it is common practice <strong>to</strong> fire<br />
wood chip, coal, peat, oil and wastes both <strong>to</strong>ge<strong>the</strong>r and separately. This flexibility is bought at <strong>the</strong> cost of<br />
greater complexity however and <strong>the</strong>y are unlikely <strong>to</strong> be cost effective lower output alternatives.<br />
Good modern examples of fluidised bed burners from <strong>the</strong> Bioenergy capital grants scheme are at<br />
Lockerbie (43MWe) and Wil<strong>to</strong>n (31MWe). Both are fuelled <strong>by</strong> a mix of forestry wood chip and graded<br />
waste wood from wood recycling operations.<br />
Steam Boilers<br />
There are two types of boiler in common usage, fire tube and water tube.<br />
Fire tube boilers, as <strong>the</strong> name suggests, transfer <strong>the</strong> heat from <strong>the</strong> fire <strong>to</strong> <strong>the</strong> water <strong>by</strong> passing <strong>the</strong> hot flue<br />
gasses through tubes inserted in a pressure vessel containing <strong>the</strong> boiling water. Typically <strong>the</strong> gas will<br />
pass backwards and forwards three times through <strong>the</strong> boiler – three tube passes. They are inexpensive<br />
and manufactured in volume. Typically <strong>the</strong> furnace supplier will purchase <strong>the</strong> boiler and adapt it <strong>to</strong> his<br />
system. Fire tube boilers are manufactured in sizes up <strong>to</strong> 50 <strong>to</strong>nnes steam/h and a typical steam<br />
pressure of 20bar, although 40bar is possible. They produce only saturated steam but a variant is<br />
available that allows for superheating <strong>by</strong> installing a heat exchanger after <strong>the</strong> second tube pass. This is a<br />
cost effective solution for industrial plants that require smaller turbines, typically 1 - 2MWe.<br />
Water tube boilers generate steam inside of tubes that are installed around <strong>the</strong> furnace and in banks<br />
across <strong>the</strong> flue gas. The temperatures and pressure of <strong>the</strong> steam can be much higher than in water tube<br />
boilers. Utility boilers can reach supercritical conditions. For large biomass boilers 520°C and 120 bar is<br />
not uncommon. Smaller units that might be appropriate for a CHP installation would have temperatures<br />
of 450°C and 50 bar. They can be manufactured in much larger sizes than fire tube boilers and tend <strong>to</strong><br />
overlap <strong>the</strong> <strong>to</strong>p end of <strong>the</strong> fire tube range.<br />
Grate burners can be installed with ei<strong>the</strong>r fire tube or water tube boilers. Fluidised beds are normally<br />
installed with water tube boilers.<br />
Control of emissions<br />
The combustion gases are cleaned <strong>by</strong> a sequence of process stages that remove particulates, acid gases<br />
and trace organic compounds such as dioxins and furans. The number of stages <strong>the</strong>ir type and<br />
complexity depends upon <strong>the</strong> composition of <strong>the</strong> waste, its legal classification under <strong>the</strong> Waste<br />
Incineration Directive and <strong>the</strong> size of <strong>the</strong> installation. The main species <strong>to</strong> be removed and abatement<br />
technologies are summarised below in Table 55.<br />
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Table 55 Pollution and <strong>the</strong> abatement methods for combustion of waste<br />
Pollutant Method of removal<br />
Particulates or aerosols Fabric or electrostatic filters, for smaller<br />
boilers and cleaner fuel cyclones or<br />
multiclone.<br />
Acid gasses mainly from sulphur and Dry or liquid carbonate wash or dry<br />
chlorine<br />
absorber.<br />
Dioxin and o<strong>the</strong>r organic compounds Active carbon absorber, can be combined<br />
with dry carbonate scrub<br />
Oxides of nitrogen. Injection of ammonia or urea in<strong>to</strong><br />
combustion zone. Catalytic removal from<br />
<strong>the</strong> flue gas.<br />
The main concerns on pollution from incinera<strong>to</strong>rs relate <strong>to</strong> <strong>the</strong> health effects of dioxins and o<strong>the</strong>r<br />
chemicals such as PCBs (poly chlorinated biphenyls) and PAHs (poly aromatic hydrocarbons). These<br />
compounds accumulate in body fat and are persistent.<br />
Dioxins are not present in nature. The term is loosely used <strong>to</strong> describe <strong>the</strong> whole family of <strong>to</strong>xic organic<br />
micro-pollutant emissions that may be formed during and after combustion. They have been associated<br />
with poorly run incineration in <strong>the</strong> past when chlorine containing wastes such as PVC, paper and card and<br />
treated wood were burnt, and this association persists.<br />
Understanding of how dioxins are formed has led <strong>to</strong> advances in process design and control that have<br />
resulted in <strong>the</strong> emissions from <strong>the</strong> incineration sec<strong>to</strong>r falling dramatically in <strong>the</strong> UK. Scientific studies<br />
have shown that <strong>the</strong> impact of emissions from an individual plant is very low. Dioxin emissions have<br />
reduced <strong>by</strong> more than 90% in <strong>the</strong> UK in <strong>the</strong> past 20 years. Never<strong>the</strong>less <strong>the</strong>re remains acute public<br />
concern over <strong>the</strong> issue, despite <strong>the</strong> fact that local authorities have access <strong>to</strong> this information.<br />
PCBs are classified as persistent in <strong>the</strong> environment and as being probably carcinogenic <strong>to</strong> humans.<br />
They have also been linked <strong>to</strong> sub-chronic effects such as reduced male fertility and long-term<br />
behavioural and learning impairment. They may originate from flexible plastic waste, paint waste, as well<br />
as transformers and capaci<strong>to</strong>rs. PAHs are a large group of chemical compounds and are carcinogenic.<br />
They may originate from waste wood, tar or fat waste for example.<br />
Sampling and analysis costs for all of <strong>the</strong>se compounds are high due <strong>to</strong> <strong>the</strong> specialised nature of <strong>the</strong><br />
equipment and trained labora<strong>to</strong>ry personnel required. This restricts <strong>the</strong> frequency of data collection. For<br />
this reason <strong>the</strong> public express concern regarding <strong>the</strong> reliability of data. A simpler, on-line test would be<br />
more satisfac<strong>to</strong>ry but due <strong>to</strong> <strong>the</strong> nature of dioxins this is a long way off.<br />
Smaller installations burning wood that do not have particulate removal equipment have also given rise <strong>to</strong><br />
concern recently. This is due <strong>to</strong> <strong>the</strong> nature of emissions from wood firing. The ash composition contains<br />
alkali components that vaporise at <strong>the</strong> furnace temperature <strong>to</strong> later condense in <strong>the</strong> cold atmosphere as<br />
aerosols with a size that is respirable. There is a similar problem with condensable organics in batch fed<br />
wood combustion devices where poor combustion control allows <strong>the</strong> formation of aerosols of organic<br />
compounds and soot. These are particularly worrying as <strong>the</strong>y contain carcinogenic materials such as<br />
furans and aromatics. This is only likely <strong>to</strong> be a problem in urban areas where <strong>the</strong> aggregate effect of<br />
several installations in a small area coupled with o<strong>the</strong>r sources such as diesel traffic could give<br />
unacceptable impacts. Local Authorities are being issued with revised guidelines on this issue and this<br />
should resolve <strong>the</strong> situation.<br />
The ash leaves <strong>the</strong> process as two distinct streams – bot<strong>to</strong>m ash that falls out of <strong>the</strong> combustion grate or<br />
bed, and fly ash that is separated from <strong>the</strong> flue gases. Bot<strong>to</strong>m ash is considered <strong>to</strong> be inert and, after <strong>the</strong><br />
separation of metals, is ei<strong>the</strong>r disposed of <strong>to</strong> general landfill or used as aggregate. Fly ash, however, can<br />
contain heavy metal contamination and, with certain chlorine containing wastes, dioxin so must be
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disposed of in a controlled landfill site. Recent European practice involves melting fly ash <strong>to</strong> form a glass<br />
that reduces <strong>the</strong> mobility of <strong>the</strong> metal ions and destroys dioxin. Following this treatment <strong>the</strong> ash can be<br />
used as aggregate or filler.<br />
Impact of waste composition on boiler performance<br />
There are two main impacts that must be managed <strong>by</strong> <strong>the</strong> designers and opera<strong>to</strong>rs of waste combustion<br />
plant; acid gas and ash fouling.<br />
Chlorine is always present in mixed waste streams and derives largely from plastics but also from paper<br />
and card. The chorine is converted in<strong>to</strong> hydrochloric acid in <strong>the</strong> combustion chamber, and this can cause<br />
excessive corrosion in <strong>the</strong> boiler, particularly at high temperatures. Restricting <strong>the</strong> temperature and<br />
pressure of <strong>the</strong> steam produced <strong>by</strong> <strong>the</strong> incinera<strong>to</strong>r limits <strong>the</strong> corrosion risk but also restricts <strong>the</strong> electrical<br />
efficiency that can be achieved.<br />
Circulating fluidised bed combus<strong>to</strong>rs have an advantage in treating wastes with a high chlorine content in<br />
that <strong>the</strong> high temperature boiler surface can be located in <strong>the</strong> circulating bed material where <strong>the</strong> chlorine<br />
concentration is lower.<br />
The oxides and salts of silicon and alkali metals are present in biomass derived wastes <strong>to</strong> a much larger<br />
extent than fossil fuels. The content increases with <strong>the</strong> proportion of annual growth material in <strong>the</strong> fuel.<br />
Thus, straw and o<strong>the</strong>r annual crop residues contain large quantities as does <strong>the</strong> bark and outer layers of<br />
trees. These components have low melting points that can lie below <strong>the</strong> temperature of <strong>the</strong> furnace, <strong>the</strong>y<br />
also have a propensity <strong>to</strong> form low melting point eutectic mixtures with o<strong>the</strong>r ash components. The liquid<br />
ash can adhere <strong>to</strong> heat transfer surfaces causing a reduction in output, sites for corrosion, and<br />
occasionally physical damage. Fluidised beds are also susceptible <strong>to</strong> agglomeration and eventual<br />
sintering and fusing due <strong>to</strong> <strong>the</strong> sticky nature of soft and liquid ash.<br />
Problems caused <strong>by</strong> ash chemistry are some of <strong>the</strong> most intractable in <strong>the</strong> industry and require <strong>the</strong><br />
application of substantial knowledge and experience in sourcing and blending feeds<strong>to</strong>cks and instituting<br />
regular boiler cleaning procedures. Suppliers of fluidised bed boilers have learned <strong>to</strong> manage <strong>the</strong><br />
chemistry of <strong>the</strong>ir bed materials <strong>to</strong> avoid low melting point eutectics <strong>by</strong> <strong>the</strong> addition of materials such as<br />
dolomite.<br />
A comprehensive review and a discussion of best practice for waste combustion is given in <strong>the</strong> supporting<br />
documentation for <strong>the</strong> Waste Incineration Directive 196<br />
Co-firing biofuels with fossil fuels<br />
The concept of co-firing biofuels with coal is one means of increasing <strong>the</strong> combustion of biomass in an<br />
existing power plant without incurring excessive capital costs. This approach has received increased<br />
attention recently, particularly in Denmark, <strong>the</strong> Ne<strong>the</strong>rlands and <strong>the</strong> US. The details of over 300 co-firing<br />
installations can be found on <strong>the</strong> IEA Bioenergy Agreement Task 32 database of co-firing installations. 197<br />
The way in which biomass is fired depends on <strong>the</strong> quantities involved. Where biomass quantities are<br />
small (2- 5%), <strong>the</strong> biomass is mixed with <strong>the</strong> coal at <strong>the</strong> mill inlet. Where biomass constitutes 5-25% of <strong>the</strong><br />
<strong>to</strong>tal fuel, shredded biomass is fired through dedicated burners. Beyond <strong>the</strong> 25% level, new concepts will<br />
be needed because combustion of that amount of biomass will have a substantial impact on both furnace<br />
and ash behaviour. Current opinion within <strong>the</strong> industry is that this will probably mean converting <strong>the</strong> fuel<br />
<strong>to</strong> gas.<br />
Current practice in <strong>the</strong> UK is <strong>to</strong> receive <strong>the</strong> fuel on site in <strong>the</strong> form of pellets that are stable, easy <strong>to</strong><br />
handle and break easily in <strong>the</strong> coal mills.<br />
196 European Integrated Pollution and Prevention and Control Bureau Waste Incineration Bref (08.06) http://eippcb.jrc.es/pages/FActivities.htm<br />
197 http://www.ieabcc.nl/database/cofiring.php<br />
111
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8.2 Review of UK and international waste combustion<br />
practice<br />
8.2.1 Combustion of MSW for energy in <strong>the</strong> UK<br />
There are a number of MSW energy recovery plants in operation in <strong>the</strong> UK using combustion technology,<br />
and numerous examples worldwide.<br />
In <strong>to</strong>tal in <strong>the</strong> UK, 45.1% (12.9 million <strong>to</strong>nnes) of MSW had value recovered from it in 2007/08 (including<br />
recycling, composting, energy from waste and fuel manufacture), a rise from 41.8% (12.2 million <strong>to</strong>nnes)<br />
in 2006/07. It has been estimated that Energy from Waste (EfW) capacity in <strong>the</strong> UK in 2007 reached 4.9<br />
million <strong>to</strong>nnes. 198<br />
The vast majority of sites in <strong>the</strong> UK that combust mixed waste and recover energy use MSW. This is<br />
because <strong>the</strong> long term contracts available from local authorities for waste management enable <strong>the</strong><br />
development of what are very high capital cost plants. However, <strong>the</strong>re are some merchant plants being<br />
proposed in <strong>the</strong> UK and Lakeside is one of <strong>the</strong> first of <strong>the</strong>se. These plants are being developed without<br />
MSW contracts, and, although MSW will probably dominate input, <strong>the</strong>se plants will also have more<br />
flexibility <strong>to</strong> take commercial and industrial waste streams.<br />
Table 56 Current EfW of MSW <strong>to</strong> generate electricity 199<br />
Site and<br />
Opera<strong>to</strong>r<br />
Edmon<strong>to</strong>n, SITA<br />
/ London Waste<br />
Alling<strong>to</strong>n<br />
Quarry, Kent<br />
Enviropower Ltd<br />
Coventry,<br />
Coventry and<br />
Solihull Waste<br />
Disposal<br />
SELCHP, Onyx<br />
Selchp<br />
Tyseley, Veolia<br />
Environmental<br />
Services<br />
Sheffield ERF,<br />
Veolia ES<br />
Billingham,<br />
Cleveland WTE,<br />
Sita UK<br />
Marchwood,<br />
Veolia<br />
Environmental<br />
Location Quantity of<br />
MSW<br />
<strong>to</strong>nnes p.a.<br />
Energy<br />
Generation<br />
Operational<br />
North London 500,000 55MWe 1989<br />
Kent 500,000 with<br />
separation of<br />
65,000 t for<br />
recycling.<br />
50 MWe<br />
Warwickshire 250,000 20 MWe and<br />
14.5 MWe<br />
2007<br />
2000<br />
Middlesex 420,000 30 MWe 1994<br />
Warwickshire 350,000 28 MWe<br />
(25MWe<br />
exported <strong>to</strong><br />
grid)<br />
Sheffield 225,000 19MWe and<br />
Teesside 350,000 being<br />
increased <strong>to</strong><br />
Southamp<strong>to</strong>n,<br />
Hampshire<br />
60MWh<br />
19 MWe<br />
1996<br />
2007<br />
1998<br />
475,400<br />
165,000 15MWe 2006<br />
198 Mass burn begins its big breakthrough, ENDS Report 394, November 2007, p.28-31.<br />
199 Waste <strong>to</strong> Energy Plants in <strong>the</strong> UK, http://www.industcards.com/wte-uk.htm, EPER UK Facilities Report, 2001,<br />
http://www.eper.ec.europa.eu/eper2/Activity_FacilityList.asp?year=2001&area=UK&id=17&EmissionAir=on
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Site and<br />
Opera<strong>to</strong>r<br />
Services<br />
Marchwood,<br />
Veolia<br />
Environmental<br />
Services<br />
Portsmouth,<br />
Veolia<br />
Environmental<br />
Services<br />
Havant, Veolia<br />
Environmental<br />
Services<br />
S<strong>to</strong>ke Sideway,<br />
S<strong>to</strong>ke on Trent<br />
Bol<strong>to</strong>n, Greater<br />
Manchester<br />
Waste Ltd<br />
Kirklees Waste<br />
<strong>to</strong> Energy Plant,<br />
Sita UK<br />
Baldovie,<br />
Dundee EfW<br />
Plant<br />
Dudley, Dudley<br />
Waste Services<br />
Ltd<br />
Location Quantity of<br />
MSW<br />
<strong>to</strong>nnes p.a.<br />
Energy<br />
Generation<br />
Operational<br />
Hampshire 165,000 14 MWe 2004<br />
Hampshire 165,000 14 MWe 2005<br />
Portsmouth,<br />
Hampshire<br />
165,000 14MWe 2006<br />
Staffordshire 200,000 12.5MWe 1997<br />
Lancashire 120,000 10 MWe 2000<br />
refurbishment<br />
Huddersfield 136,000 9MWe 2002<br />
Dundee,<br />
Scotland<br />
120,000 of<br />
course SRF,<br />
from<br />
MSW and C&I<br />
8MWe<br />
1999<br />
Staffordshire 90,000 7.4 MWe 1998<br />
Chineham,<br />
Veolia ES<br />
Hampshire Ltd<br />
Hampshire 90,000 7 MWe 2003<br />
Wolverhamp<strong>to</strong>n West 105,000 7MWe 1998<br />
Isle of Man EfW<br />
Plant, Sita UK<br />
Grims<strong>by</strong>,<br />
NewLincs<br />
Development<br />
Ltd<br />
Midlands<br />
Isle of Mann 60,000<br />
including tyres<br />
North East<br />
Lincolnshire<br />
6MWe (5MW<br />
exported <strong>to</strong><br />
grid)<br />
56,000 3.45 MWe<br />
and 3 MWh<br />
as CHP<br />
2005<br />
2004<br />
Estimations of energy efficiency for each plant are difficult <strong>to</strong> make as such figures are not <strong>read</strong>ily<br />
available and <strong>the</strong> waste input may vary, affecting <strong>the</strong> efficiencies.<br />
It is likely that <strong>the</strong> number of EfW combustion plants will increase in <strong>the</strong> future. To meet <strong>the</strong> UK’s 2013<br />
and 2020 landfill diversion targets it has been estimated that an additional 8.5 million <strong>to</strong>nnes of annual<br />
processing capacity for MSW alone will be required. 200 It is likely that a proportion of this will be as EfW<br />
plants with potentially 25% of MSW going <strong>to</strong> EfW eventually.<br />
200 Waste Infrastructure Delivery Programme (WIDP) Action Plan, Defra, http://www.defra.gov.uk/environment/waste/wip/widp/documents/widp-<br />
actionplan.pdf<br />
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Although using waste as a resource for energy generation is likely <strong>to</strong> increase, <strong>the</strong> output of <strong>the</strong> UK’s EfW<br />
plants above is small compared <strong>to</strong> <strong>the</strong> energy generated through traditional methods such as coal power<br />
stations. The sum of output described above is 395MW, where as Britain’s traditional power stations’<br />
output was 75,000MW in 2007. 201<br />
Four new EfW plants (with associated recycling and reprocessing facilities) are planned for London in <strong>the</strong><br />
near future, based on <strong>the</strong> Mayor of London's Waste Strategy. 202 These are: Dagenham, Newhaven (in<br />
East Sussex), Lakeside and Belvedere. The Dagenham proposal includes a proposed gasification plant<br />
<strong>to</strong> process 100,000 <strong>to</strong>nnes of waste each year and generate 15MW of electricity. Contracts between<br />
Shanks, <strong>the</strong> opera<strong>to</strong>r, and Ford, <strong>the</strong> beneficiary, have been signed but construction has been delayed.<br />
The Newhaven site has <strong>full</strong> planning permission and it is intended that <strong>the</strong> steam produced will be used<br />
for heat energy. 203 The Lakeside EfW Ltd site will be capable of handling 410,000 <strong>to</strong>nnes of waste per<br />
annum and is expected <strong>to</strong> open in July 2009, 204 while <strong>the</strong> Belvedere site in South East London is<br />
expected <strong>to</strong> process 600,000 <strong>to</strong>nnes per annum of waste and generate 66MW of electricity.<br />
In addition INEOS Chlor on Merseyside has permission <strong>to</strong> build a site capable of consuming 800,000<br />
<strong>to</strong>nnes of stabilised fuel from municipal waste, generating 100MW of electricity and 360MW of heat <strong>to</strong> be<br />
used largely on <strong>the</strong> chemicals site.<br />
International Situation<br />
The numbers of EfW plants world-wide continues <strong>to</strong> grow. Several countries in Europe, for example<br />
Denmark and Germany, have a strong his<strong>to</strong>ry of incineration, and <strong>the</strong> process is widely accepted <strong>by</strong> <strong>the</strong><br />
public. Such countries have found it relatively easy <strong>to</strong> move <strong>to</strong> EfW plants in terms of public perception,<br />
and as such use of EfW tends <strong>to</strong> be more widesp<strong>read</strong>.<br />
Currently <strong>the</strong>re are at least 91 sites throughout Western Europe that use MSW as <strong>the</strong> main fuel source for<br />
EfW combustion plants. Some of <strong>the</strong>se sites augment <strong>the</strong> MSW with bio-solids, wood, straw, and hospital<br />
waste depending on <strong>the</strong> site. World wide <strong>the</strong>re are at least 154 industrial scale waste <strong>to</strong> energy plants, a<br />
considerable number are in <strong>the</strong> USA, while China and Taiwan also have several each.<br />
Japan has many functioning EfW facilities as well as numerous straight incinera<strong>to</strong>rs. This is due <strong>to</strong> <strong>the</strong><br />
policy of waste minimisation that has been pursued for a number of decades, due <strong>to</strong> <strong>the</strong> limited land<br />
space. Only recently has deriving energy from <strong>the</strong> waste incineration process become a priority. Of<br />
Japan’s 1,301 incinera<strong>to</strong>rs in 2006, 293 generated electricity (7,190 GWh per annum). 205 Of <strong>the</strong>se<br />
facilities 7.4% do not carry out direct incineration, but convert waste <strong>to</strong> energy and fuels via o<strong>the</strong>r<br />
technologies, 206 which represents a 5-fold increase between 2001and 2006. 205 Such technologies are<br />
discussed below.<br />
8.2.2 Biomass CHP Plant for Commercial Food Waste<br />
In Widnes, Cheshire a combustion biomass CHP plant is operated <strong>by</strong> PDM, that is heavily utilised <strong>by</strong> 28<br />
Sainsbury’s s<strong>to</strong>res in Scotland, for disposal of 56,000 <strong>to</strong>nnes of commercial food waste. 207 The excess<br />
electricity generated is fed in<strong>to</strong> <strong>the</strong> grid, and <strong>the</strong> heat produced utilised <strong>by</strong> an adjacent chemicals<br />
company. Meat is separated for rendering and packaging for recycling before <strong>the</strong> waste is burnt.<br />
Sainsbury’s intends <strong>to</strong> extend <strong>the</strong> scheme <strong>to</strong> all s<strong>to</strong>res, sending additional material <strong>to</strong> <strong>the</strong> CHP biomass<br />
201 Giant offshore wind farms <strong>to</strong> supply half of UK power, The Sunday Times, 9 th December 2007.<br />
202 London Development Agency Press Release 2007, http://www.lda.gov.uk/server/show/ConWebDoc.2127<br />
203 Newhaven Incinera<strong>to</strong>r Clears Final Hurdle, 17.03.09, LetsRecycle.com<br />
http://www.letsrecycle.com/do/ecco.py/view_item?listid=37&listcatid=217&listitemid=31241<br />
204 Lakeside EfW Project Update, Viridor Waste Management, http://www.viridor-waste.co.uk/lakeside-energy-from-waste-project-update<br />
205 The status of MSW Management, 2005, http://www.env.go.jp/press/press.php?serial=8277<br />
206 Japan's waste management 2006, published September 2008, Department of Environment Japan,<br />
http://www.env.go.jp/recycle/waste_tech/ippan/h18/data/disposal2.doc<br />
207 ENDS Report 409, February 2009, p.18-19, Supermarkets burn food waste as anaerobic digestion shortage bites.
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site at Hartshill, near Nunea<strong>to</strong>n. Asda is using a similar programme for 20 of its s<strong>to</strong>res, sending some<br />
waste <strong>to</strong> Veolia’s CHP site in Sheffield (included in Table 56 above).<br />
PDM have also received planning permission for a £25 million 150,000 <strong>to</strong>nnes per annum biomass plant<br />
close <strong>to</strong> <strong>the</strong> above facility in Widnes.<br />
8.2.3 Utilising Wood - C&D Waste, Sawmill products, Forestry Residues<br />
Utilising forestry residues is largely carried out on a local scale, with clean wood being used in small scale<br />
biomass boilers.<br />
In <strong>the</strong> UK a significant amount of waste wood is used within <strong>the</strong> wood working industry. For example,<br />
wood waste may be used at furniture manufacturing sites <strong>to</strong> generate process heat. The level of<br />
utilisation of such a resource is unpublished, but it has been estimated that <strong>the</strong>re are at least 275 smallscale<br />
wood-burning boilers in <strong>the</strong> UK (0.4 – 3MW), consuming 223,500 <strong>to</strong>nnes of wood each year in <strong>the</strong><br />
furniture industry. 208 Such figures do not include throughputs for <strong>the</strong> larger scale boilers used <strong>by</strong> <strong>the</strong><br />
panel board manufacturing industry.<br />
One instance of waste wood being processed for utilisation is <strong>by</strong> Wood Pellet Energy Ltd in County<br />
Durham, which collects wood waste from business and households in <strong>the</strong> region. They convert wood<br />
waste, which would o<strong>the</strong>rwise go <strong>to</strong> board manufacturing, <strong>to</strong> fuel pellets. Annual production is<br />
approximately 12,000 <strong>to</strong>nnes, with output expected <strong>to</strong> rise. The pellets produced from ‘clean’ waste wood<br />
are <strong>the</strong>n used <strong>by</strong> Durham County Council <strong>to</strong> heat twelve of its schools, schools in Northumberland and<br />
North Yorkshire and parts of Leeds University. Pellets that have been produced from treated wood can<br />
only be used in boilers that are WID compliant such as at Sembcorp Biomass Power Station at Teesside.<br />
E.ON received permission in 2008 <strong>to</strong> build an energy plant at Blackburn Meadows in Sheffield, that uses<br />
recycled wood as <strong>the</strong> fuel source. Construction is expected <strong>to</strong> begin in 2009, with <strong>full</strong> commercial<br />
operation expected in 2011. It is intended <strong>to</strong> generate 25 MW of electricity. 209<br />
Table 57 Wood utilising energy generation systems<br />
Site and<br />
Opera<strong>to</strong>r<br />
Port Talbot<br />
biomass<br />
power station<br />
Eccleshall<br />
Biomass<br />
energy<br />
RSPB Old<br />
Moor<br />
Sheffield<br />
Road Flats<br />
(166 flats),<br />
Barnsley<br />
Metropolitan<br />
Borough<br />
Council<br />
Location Quantity of Wood Generation<br />
Capacity<br />
Port Talbot,<br />
South Wales<br />
120k <strong>to</strong>nnes forestry and<br />
sawmill residues.<br />
13.5MWe<br />
Electricity<br />
only<br />
Staffordshire 20k <strong>to</strong>nnes wood chip and<br />
miscanthus<br />
2.3MWe<br />
South Yorkshire 3 <strong>to</strong>nnes of fuel (12m 3 )<br />
delivered twice per week<br />
during winter, once every<br />
two weeks during <strong>the</strong><br />
summer.<br />
Barnsley 100m 3 of fuel gives 1 weeks<br />
supply in winter and 3 <strong>to</strong> 4<br />
weeks in summer.<br />
208 Benchmarking wood waste combustion, BFM, 2005,<br />
http://www.bfmenvironment.co.uk/images/BFM%20Wood%20combustion%20benchmarking%20-%20<strong>full</strong>1.pdf<br />
209 E.ON, Blackburn Meadows, http://www.eon-uk.com/generation/1490.aspx<br />
100kW<br />
Heating<br />
1 x 320 kW<br />
and 1 x 150<br />
kW<br />
providing<br />
space and<br />
water<br />
heating<br />
Operational<br />
2008<br />
2007<br />
2004<br />
2004<br />
115
116<br />
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Bio-energy Capital Grants Scheme<br />
The Bioenergy Capital Grants Scheme (BEGS) was launched in 2002. Four funding rounds have been<br />
held over <strong>the</strong> past five years <strong>to</strong> support various aspects of <strong>the</strong> Bioenergy sec<strong>to</strong>r. DTI and <strong>the</strong> Lottery<br />
funded <strong>the</strong> first two rounds and Defra <strong>the</strong> third and fourth. The fifth round funded <strong>by</strong> DECC was launched<br />
in Dec 2008 and <strong>the</strong> successful applicants have just been announced.<br />
The objectives are focused on building <strong>the</strong> basis of an industry, and providing a learning experience. This<br />
has directed <strong>the</strong> scheme <strong>to</strong>wards a broad portfolio of projects that captures a wide range of technologies<br />
and companies.<br />
The scheme has produced <strong>the</strong> following highlights:<br />
• Two major power plant projects in operation at Lockerbie and Middlesbrough see Box 4.<br />
• Several electricity/CHP installations in operation located in South Wales, Nor<strong>the</strong>rn Ireland, and<br />
Staffordshire including anaerobic digestion.<br />
• 1 x 5.4 MWe industrial CHP at a brewery. Replications are al<strong>read</strong>y being planned across <strong>the</strong><br />
sec<strong>to</strong>r.<br />
• 1 x 1.4 MWe gasification CHP <strong>to</strong> supply a University Campus.<br />
• A core industry of suppliers installing biomass boilers with over 400 installations so far.<br />
• Parallel generation of local wood fuel suppliers extracting local woodlands and resources. Each<br />
region now has several suppliers.<br />
• Nine projects with local authorities that demonstrate public sec<strong>to</strong>r leadership in developing carbon<br />
abatement strategies. For example, Nottingham is converting all <strong>the</strong>ir schools <strong>to</strong> wood heating.<br />
• Started UK pellet fuel industry <strong>by</strong> supporting <strong>the</strong> Balcas sawmill CHP plant in Nor<strong>the</strong>rn Ireland,<br />
producing 40k <strong>to</strong>nnes pellets per annum. Balcas are now replicating this, at double <strong>the</strong> size, in<br />
Scotland based on <strong>the</strong> experience.<br />
• Initiated a new industry in recovered wood fuel in <strong>the</strong> North East and North West <strong>by</strong> providing a<br />
market for over 200k <strong>to</strong>nnes per annum. E.ON and o<strong>the</strong>rs are now planning fur<strong>the</strong>r installations<br />
<strong>to</strong> use this resource.<br />
• Average cost of carbon abatement: £132 of Government funding per annual <strong>to</strong>nne abated in later<br />
rounds.
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Box 4: New UK Projects burning graded waste wood supported <strong>by</strong> <strong>the</strong> Bioenergy<br />
Capital Grants Scheme<br />
Wil<strong>to</strong>n 10: Wood Burning Power Station<br />
Wil<strong>to</strong>n 10 at Teeside, Middlesborough, was <strong>the</strong> UK’s first large scale biomass power station,<br />
built at a cost of £60m, and commencing operation in 2007. It is owned and run <strong>by</strong> SembCorp<br />
Utilities, using 300,000 <strong>to</strong>nnes of wood as <strong>the</strong> fuel source and sourcing this material from a<br />
mixture of waste wood from civic amenity sites, C&D sites and waste firms (40%), primary<br />
processing products (20%), arboricultural arisings sourced from <strong>the</strong> north east region’s<br />
forestry commission and dedicated coppice grown as an energy crop. All material is s<strong>to</strong>red<br />
and chipped on a neighbouring site <strong>to</strong> <strong>the</strong> power station.<br />
The power station uses a bubbling fluidised bed boiler, capable of handling <strong>the</strong> high moisture<br />
fuel and <strong>the</strong> ash produced from <strong>the</strong> wood. The Siemens steam turbine is used <strong>to</strong> generate<br />
33MW of electricity, which is sold directly <strong>to</strong> <strong>the</strong> grid. In addition 10MWth of steam is available<br />
and this is used <strong>by</strong> <strong>the</strong> sites district heating steam circuit, largely as process heat.<br />
Steven’s Croft: Wood Burning Power Station<br />
Steven's Croft, in Lockerbie, Scotland, is currently <strong>the</strong> UK’s largest biomass power station. It<br />
is owned and run <strong>by</strong> E.ON, who opened it in 2008. The cost of building was £90m including<br />
£18m from <strong>the</strong> Big Lottery Grant.<br />
It utilises 480,000 <strong>to</strong>nnes of wood each year of which is sourced principally from forestry coproducts<br />
from within a 60 mile radius, up <strong>to</strong> 20% recycled wood from wood product<br />
manufacture, and some short rotation coppice willow. It is intended that <strong>by</strong> 2012 90,000<br />
<strong>to</strong>nnes of wood will be sourced from locally grown willow. The output is 44MW of electricity <strong>to</strong><br />
<strong>the</strong> national grid.<br />
There are a considerable number of facilities that use forestry residues and sawmill co-products<br />
internationally. The table below signposts <strong>to</strong> sources of information regarding <strong>the</strong> most important<br />
markets internationally.<br />
Table 58 Forestry waste <strong>to</strong> energy facilities<br />
Country Feeds<strong>to</strong>ck Comments<br />
Finland 210 Forestry<br />
residues and<br />
saw mill coproducts<br />
Finland has several power plants that utilise <strong>the</strong> widely available<br />
resource of wood, with much of <strong>the</strong> resource coming from forestry<br />
residues and saw-mill co-products. Many of <strong>the</strong>se are CHP<br />
systems. In addition Finland has two plants that are fuelled <strong>by</strong> <strong>the</strong><br />
waste from paper processing plants – called Black Liquor, <strong>the</strong><br />
lignin and hemicellulose fragments of wood. The generation<br />
capacity of <strong>the</strong>se plants ranges from 17-240MW.<br />
The CHP plant of Pietarsaari (Alholmens Kraft Power) is <strong>the</strong><br />
world’s largest biofuel CHP plant with an output of 240 MW of<br />
electricity, 100 MW process steam and 60 MW of district heat. It<br />
began operating in 2001 and processes 150,000 - 200,000m 3 of<br />
logging residues (as well as peat and black liquors from <strong>the</strong> paper<br />
mill). 211<br />
210 The World’s largest biofuel CHP plant, http://www.itebe.org/telechargement/revue/Revue5/Revue5-UK/RevueBE5-UK-p42.pdf<br />
211 Alholmens Kraft, http://www.metso.com/corporation/home_eng.nsf/FR?ReadForm&ATL=/corporation/about_eng.nsf/ WebWID/WTB-<br />
071102-2256F-C513C<br />
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Country Feeds<strong>to</strong>ck Comments<br />
Italy 212 Forestry<br />
Residues<br />
Italy has five biomass power stations that burn wood and make<br />
some use of Forestry residues.<br />
One is <strong>the</strong> CHP system in Pozzilli, opened in 1997,which takes<br />
70,00 – 80,000 <strong>to</strong>nnes per annum of wood residues as well as<br />
agricultural residues (hazelnut shells, olive kernels, fruit s<strong>to</strong>nes,<br />
pine cone seed residues) <strong>to</strong> generate an output of 9.8 MW.<br />
Sweden Wood waste Sweden has 3 biomass power plants that burn waste wood, and<br />
Iwakuni,<br />
Japan 213<br />
Anderson,<br />
USA 214,215<br />
8.2.4 Straw<br />
Forestry<br />
Residues<br />
Forestry<br />
Residues<br />
one of <strong>the</strong>se also burns waste tyres.<br />
A co-generation station that has used 90,000 <strong>to</strong>nnes per annum of<br />
logging residues since 2006. Operated <strong>by</strong> First Energy Service<br />
Company Ltd. The first biomass plant of larger than 10MW.<br />
Operated <strong>by</strong> Signal Shasta Energy Co it has been operational<br />
since 1989 and utilises 750,000 <strong>to</strong>nnes per annum of mill waste<br />
and forest residues, with a generation capacity of 3 x 18MW.<br />
There is one straw burning power station in <strong>the</strong> UK, <strong>the</strong> Elean station in Ely, Cambridgeshire, constructed<br />
<strong>by</strong> Energy Power Resources Ltd (EPRL) and in operation since 2000. 216 This plant uses 200,000 <strong>to</strong>nnes<br />
per annum, generates 38MW of electricity and cost £60M <strong>to</strong> build. It is also capable of burning a range of<br />
o<strong>the</strong>r bio-fuels. This plant uses a vibrating grate with conventional steam cycle. The opera<strong>to</strong>r requires<br />
relatively dry straw, so bales over 650 kg at 16% moisture content command an average price while <strong>the</strong>re<br />
is a price penalty for bales that are ei<strong>the</strong>r less dense than this or have a higher moisture content. EPRL<br />
have developed moni<strong>to</strong>ring equipment <strong>to</strong> enable <strong>the</strong>m <strong>to</strong> assess moisture and density as <strong>the</strong> bales enter<br />
<strong>the</strong> plants.<br />
Straw has a high potassium and sodium salt content which can lead <strong>to</strong> increased deposits and corrosion<br />
when using straw.<br />
Small–scale straw burning boilers are available in <strong>the</strong> UK, and it is estimated that a fur<strong>the</strong>r 17,000 <strong>to</strong>nnes<br />
per annum are used in small-scale on farm schemes. These boilers are used for a number of purposes,<br />
including heating farmhouses and associated buildings, drying grain and heating swimming pools. Many<br />
of <strong>the</strong>se plants were built as a result of grants for straw heat and power in <strong>the</strong> 1980s. However, since this<br />
Government programme s<strong>to</strong>pped, a number of <strong>the</strong> plants have been converted <strong>to</strong> wood. This is because<br />
of <strong>the</strong> problems with s<strong>to</strong>rage and handling of straw, and <strong>the</strong> problems surrounding ash corrosion.<br />
There are no schemes in <strong>the</strong> UK <strong>to</strong> co-fire straw, although some power stations are licensed <strong>to</strong> take it.<br />
Straw power plants have been built in Denmark, where <strong>the</strong>re are targets <strong>to</strong> drive this development. The<br />
Danish work has demonstrated <strong>the</strong> feasibility of large-scale co-firing of straw.<br />
212 Production of energy from biomass residues in <strong>the</strong> CHP plant of Pozzilli, Italy, 2002, http://www.tekes.fi/OPET/pdf/Energonut_IT.pdf<br />
213 Circulating Fluidized Bed Power Plant, JFE Engineering Corporation, http://www.jfe-eng.co.jp/en/en_product/environment/environment2121.html<br />
214 http://www.industcards.com/biomass-usa-ca.htm<br />
215 http://www.sl<strong>the</strong>rmal.com/pdf/Anderson,%20California.pdf<br />
216 http://www.eprl.co.uk
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Table 59 International Facilities that combust straw for heat and electricity generation<br />
Site Feeds<strong>to</strong>ck<br />
Generation<br />
Capacity Comments<br />
Denmark Straw 8.3-28 MW Straw is used in co-firing in large utility power stations in<br />
Denmark, where <strong>the</strong>re is an obligation on <strong>the</strong> powerstations<br />
<strong>to</strong> do so, for example <strong>the</strong> Grenaa site. Due <strong>to</strong><br />
<strong>the</strong> composition of straw <strong>the</strong>re have been severe<br />
problems with slagging, fouling and corrosion. In addition<br />
<strong>the</strong>re are restrictions on <strong>the</strong> temperature of operation.<br />
The Danes have overcome <strong>the</strong>se problems, most<br />
noticeably <strong>by</strong> building stand-alone boilers for <strong>the</strong> straw.<br />
More recently Denmark has built purpose designed straw<br />
power stations at Haslev that consumes 27,000 <strong>to</strong>nnes of<br />
straw per annum, and ano<strong>the</strong>r at Nakskov with an output<br />
of 6MW + 8MW. 217<br />
Przechlewo Straw N/A An old coal power station that provided heating for 18<br />
Poland<br />
houses, a school, a kindergarten and three office and<br />
public utility buildings was replaced with one that used<br />
straw as <strong>the</strong> fuel source. It is owned and run <strong>by</strong> <strong>the</strong> Local<br />
Authority and uses three Apacor Brzeg Dolny boilers, with<br />
a power rating of 2 x 2.5 MW and 1 x 1.25 MW. In<br />
addition <strong>the</strong> site has a straw warehouse, 1800m 2 -<br />
sufficient <strong>to</strong> hold 1 month’s worth of straw. The 2500 <strong>to</strong>ns<br />
of straw used each year must be shredded and<br />
compressed in<strong>to</strong> cubes, with a humidity of 22%. The site<br />
has been in operation since 2001. 218<br />
Såtenergi Straw 20,000 MWh The Air Force site at Såtenergi purchase <strong>the</strong>ir heating<br />
AB,<br />
of district from a straw fired station supplied with straw <strong>by</strong> 40 local<br />
Sweden<br />
heating farmers, who also own 9% of <strong>the</strong> station. Ash generated<br />
is returned <strong>to</strong> <strong>the</strong> fields. 219<br />
China Straw 2 x 12 MW The facility in Sugian began operation in 2006 with<br />
capacity of 200,000 <strong>to</strong>nnes per annum.<br />
8.2.5 Poultry Litter<br />
The UK has several plants that use poultry litter as a feeds<strong>to</strong>ck for energy generation. Poultry Litter is a<br />
mixture of poultry droppings and <strong>the</strong> material used as bedding, often wood chippings. The material has a<br />
calorific value between 8.8 -15GJ/t and a highly variable moisture content of between 20% and 50%,<br />
depending upon husbandry practices. The key players in <strong>the</strong> industry have now resolved most technical<br />
issues associated with using this as a fuel. The ash produced is largely used as a fertiliser, as it is high in<br />
potassium and potash.<br />
The UK has been at <strong>the</strong> forefront of power generation from poultry litter with three plants currently in<br />
operation: Eye and Thetford in England, and Westfield in Scotland. Although it is possible <strong>to</strong> co-fire<br />
poultry litter with coal, <strong>the</strong>re are few examples of this described in <strong>the</strong> literature. Poultry litter now falls<br />
under WID controls, and as such any new facility would have <strong>to</strong> comply with WID emission limits.<br />
217 Case Study: Straw fuelled heating plant in Nakskov, Denmark, European Commission, Direc<strong>to</strong>rate General for Energy and Transport.<br />
218 Case Study: Biomass straw fired boiler plant in Przechlewo, Poland, European Commission, Direc<strong>to</strong>rate General for Energy and Transport.<br />
219 Såtenergi AB- 4 MW Straw heating plant, http://www.managenergy.net/download/nr80.pdf<br />
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Table 60 Burning Poultry Litter <strong>to</strong> Generate Energy<br />
Site and<br />
Opera<strong>to</strong>r<br />
Thetford,<br />
EPRL<br />
Westfield,<br />
EPRL<br />
Location Quantity of<br />
Poultry<br />
Litter (t/yr)<br />
Generation<br />
Capacity<br />
Operational<br />
Norfolk 420,000 38.5 MW 1998 The largest<br />
poultry litter<br />
fuelled plant<br />
in <strong>the</strong> world.<br />
Fife 110,000 10 MW 2000 Uses a<br />
bubbling<br />
fluidised bed<br />
combustion<br />
system.<br />
Eye, EPRL Suffolk 140,000<br />
Plant also<br />
burns horse<br />
bedding and<br />
fea<strong>the</strong>rs<br />
It cost £22<br />
million <strong>to</strong><br />
develop and<br />
implement.<br />
12.7 MW 1992 The world’s<br />
first poultry<br />
litter fuelled<br />
plant.<br />
More than 650,000 <strong>to</strong>nnes of poultry litter are committed <strong>to</strong> <strong>the</strong> three EPRL (Energy Power Resources<br />
Ltd) plants. Significantly EPRL has contracts with <strong>the</strong> all of <strong>the</strong> largest commercial poultry farmers so it is<br />
likely that <strong>the</strong> remaining resource will be more difficult <strong>to</strong> collect and use. Never<strong>the</strong>less it is estimated that<br />
around 80% of <strong>the</strong> poultry litter in <strong>the</strong> UK could be available for energy plants, <strong>to</strong>talling 3.33 million <strong>to</strong>nnes<br />
(using <strong>the</strong> figures generated in Section 4.5), potentially with an energy content of 30 million GJ.<br />
This resource is available “free”. It is a waste with considerable disposal problems and <strong>the</strong> farmers need<br />
<strong>to</strong> get rid of it. However, EPRL pay <strong>the</strong> farmers £10/odt in order <strong>to</strong> ensure a secure supply of good quality<br />
fuel for <strong>the</strong>ir plants.<br />
Applications so far have all been for large scale power generation due <strong>to</strong> <strong>the</strong> difficult nature of <strong>the</strong> fuel<br />
that demands economy of scale <strong>to</strong> be economic. A project at <strong>the</strong> University of Manchester, supported <strong>by</strong><br />
<strong>the</strong> Carbon Trust and Keld Energy, is working <strong>to</strong> develop a small-scale power plant, 200kW,that uses a<br />
fluid bed gasifier capable of converting biomass in<strong>to</strong> combustible gas connected <strong>to</strong> a small gas turbine.<br />
Such a system would provide heat <strong>to</strong> <strong>the</strong> poultry farm, electricity <strong>to</strong> <strong>the</strong> surrounding community, and<br />
provide a bio-secure disposal route for <strong>the</strong> poultry litter. 220<br />
As discussed above agricultural residues have a wide range of composition and properties that often<br />
result in reduced performance and operating difficulties. However <strong>the</strong>y have <strong>the</strong> overwhelming<br />
advantages of being cheap and available. Engineers <strong>the</strong>refore develop robust solutions <strong>to</strong> access <strong>the</strong><br />
profit that can be generated from <strong>the</strong>se feeds<strong>to</strong>cks. We give below some examples of how problems<br />
have been addressed worldwide. In addition a recent patent issued in <strong>the</strong> USA discusses a pyrolysis<br />
method of obtaining energy from poultry litter. 221 We are aware anecdotally of o<strong>the</strong>r gasification concepts<br />
<strong>to</strong> treat poultry litter but no examples of operating plant.<br />
220 The University of Manchester, http://www.manchester.ac.uk/aboutus/news/archive/list/item/?id=3177&year=2007&month=10<br />
221 Thermochemical Method for Conversion of Poultry Litter, US2009031616 (A1), 05.02.2009.
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Table 61 Two international examples of plants that use poultry litter as feeds<strong>to</strong>ck<br />
Capacity<br />
Comments<br />
Location Year<br />
Generation<br />
Moerdijk,<br />
Ne<strong>the</strong>rlands 222<br />
2008 440,000<br />
<strong>to</strong>nnes/annum<br />
36.5 MW Constructed <strong>by</strong> <strong>the</strong> Dutch multiutility<br />
company Delta, <strong>the</strong><br />
feeds<strong>to</strong>ck is sourced through a<br />
cooperative comprised of 629<br />
separate poultry farmers. 223<br />
Benson,<br />
Minnesota,<br />
USA 224<br />
2007 500,000<br />
<strong>to</strong>nnes/annum<br />
55 MW The first poultry-litter fuelled<br />
power plant in <strong>the</strong> USA based<br />
on <strong>the</strong> Fibrowatt plants in <strong>the</strong><br />
UK.<br />
Animal Wastes<br />
The Glanford power station in North Lincolnshire was originally commissioned <strong>to</strong> burn poultry litter, but<br />
was converted <strong>to</strong> allow <strong>the</strong> burning of MBM (Meat and bone meal) in 2000 as part of <strong>the</strong> UK effort <strong>to</strong> deal<br />
with <strong>the</strong> build up of MBM resulting from <strong>the</strong> rules for slaughter and disposal of cattle suffering from BSE.<br />
As of 2004 <strong>the</strong> plant has been licensed <strong>to</strong> burn MBM from any source. It has a generation capacity of<br />
13.5MW.<br />
8.3 EfW Potential<br />
The UK has a number of incineration plants, which currently make little use of <strong>the</strong> heat generated.<br />
Table 62 shows that <strong>the</strong> current permitted incineration capacity in England and Wales in 2007 (this does<br />
not include facilities that burn waste from <strong>the</strong>ir own in-house processes) was about 8.6 million <strong>to</strong>nnes. 225<br />
Facilities for MSW account for about 50% of <strong>the</strong> <strong>to</strong>tal capacity, and only 60% of <strong>the</strong> <strong>to</strong>tal available<br />
capacity was used in 2007.<br />
Table 62 Incineration capacity (<strong>to</strong>nnes) in England and Wales for 2007. 225<br />
Type Permitted<br />
Capacity<br />
Tonnage<br />
Incinerated in<br />
2006<br />
Tonnage<br />
Incinerated in<br />
2007<br />
Animal Carcasses 85,779 22,685 19,427<br />
Animal By-Products 1,258,000 803,480 799,158<br />
Clinical 222,093 114,272 123,349<br />
Co-Incineration of hazardous<br />
waste 1,052,087 215,016 281,099<br />
Co-Incineration of non<br />
hazardous waste 972,660 99,984 347,707<br />
Hazardous 209,175 133,895 132,963<br />
Municipal 4,416,100 3,293,719 3,277,707<br />
Bio-solids 387,500 196,434 190,825<br />
Total 8,603,394 4,879,485 5,172,235<br />
222<br />
Ne<strong>the</strong>rlands plant <strong>to</strong> convert poultry litter <strong>to</strong> energy, http://www.biomassmagazine.com/article.jsp?article_id=2006<br />
223<br />
Ne<strong>the</strong>rlands Plant <strong>to</strong> Convert Poultry Litter <strong>to</strong> Energy, http://www.biomassmagazine.com/article.jsp?article_id=2006,<br />
http://www.delta.nl/web/show/id=84742<br />
224<br />
Fibromin, http://www.fibrowattusa.com/us-projects.cfm?id=16<br />
225<br />
http://www.environment-agency.gov.uk/research/library/data/97795.aspx<br />
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Table 63 shows <strong>the</strong> incinera<strong>to</strong>r throughput <strong>by</strong> region in 2007. London and <strong>the</strong> West Midlands both sent<br />
over 0.9 million <strong>to</strong>nnes <strong>to</strong> MSW facilities, and <strong>the</strong> East of England sent almost 0.6 million <strong>to</strong>nnes <strong>to</strong> animal<br />
<strong>by</strong>-product facilities.<br />
Table 63 Incinera<strong>to</strong>r throughput (‘000 <strong>to</strong>nnes) <strong>by</strong> region in 2007 225<br />
Municipal Animal<br />
<strong>by</strong>-product<br />
O<strong>the</strong>r Total<br />
East Midlands 156 - 183 339<br />
East of England - 583 46 629<br />
London 941 - 105 1,046<br />
North East 206 - 23 229<br />
North West 87 97 193 377<br />
South East 570 34 252 856<br />
South West 2 - 62 64<br />
West Midlands 944 - 102 1,046<br />
Yorkshire and Humber 358 85 105 548<br />
Wales 11 - 25 36<br />
Total 3,278 799 1,095 5,172<br />
Table 66 compares <strong>the</strong> composition of <strong>the</strong> mixed/general waste C&I stream with that for municipal solid<br />
waste. This shows that, whilst <strong>the</strong>re are differences between <strong>the</strong> two <strong>report</strong>ed analyses, in general<br />
mixed/general C&I waste stream has a higher content combustible content than overall MSW arisings.<br />
Table 64 Composition (Wt %) of MSW and mixed/general C&I waste<br />
Typical<br />
MSW<br />
Mixed/general<br />
C&I waste<br />
Report 1 226<br />
Mixed/general<br />
C&I waste<br />
Report 2 227<br />
Paper 14 22 14<br />
Cardboard 7 19 20<br />
Plastic film 3 4 7<br />
Dense plastic 4 6 5<br />
Textiles 2 1 2<br />
O<strong>the</strong>r combustibles 12 7 19<br />
Glass 6 4 4<br />
O<strong>the</strong>r non-combustibles 10 2 6<br />
Food waste 19 25 16<br />
Garden waste 14 3 2<br />
Metal 6 5 3<br />
WEEE 2 1 1<br />
Household hazardous 1 1 1<br />
Recycling initiatives for MSW have targeted and <strong>the</strong>refore removed much of <strong>the</strong> paper, cardboard, glass,<br />
plastic, metal and garden waste categories. The arisings of MSW in <strong>the</strong> UK are estimated (see Section<br />
4.1) <strong>to</strong> be 38 million <strong>to</strong>nnes per annum <strong>by</strong> 2020. If a 50% recycling target is achieved <strong>by</strong> 2020, <strong>the</strong>n 19<br />
million <strong>to</strong>nnes will be recycled, composted or sent <strong>to</strong> anaerobic digestion facilities. It is more difficult <strong>to</strong><br />
estimate <strong>the</strong> amount of MSW that will be landfilled <strong>by</strong> 2020, but if 20% (8 million <strong>to</strong>nnes) was directly<br />
landfilled, <strong>the</strong>n a potential 11 million <strong>to</strong>nnes per annum of MSW could be treated in o<strong>the</strong>r energy recovery<br />
plants (3 million <strong>to</strong>nnes per annum is al<strong>read</strong>y being processed). The need <strong>to</strong> comply with <strong>the</strong> Landfill<br />
226 The composition of municipal solid waste in Wales. Report <strong>by</strong> AEA for <strong>the</strong> Welsh Assembly Government, December 2003.<br />
227 Determination of <strong>the</strong> Biodegradability of Mixed Industrial and Commercial Waste Landfilled in Wales. Report <strong>by</strong> SLR for Environment Agency<br />
Wales, November 2007.
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Directive requirements for <strong>the</strong> diversion of biodegradable waste and for <strong>the</strong> treatment of o<strong>the</strong>r wastes<br />
prior <strong>to</strong> landfill mean that EfW is one of <strong>the</strong> likely options <strong>to</strong> treat this waste.<br />
In addition <strong>the</strong>re are <strong>the</strong> C&I and C&D wastes that will require treatment and disposal.<br />
8.4 Conclusions for Combustion Technologies<br />
Combustion, or incineration is <strong>by</strong> far <strong>the</strong> most common method of extracting energy from solid waste<br />
ei<strong>the</strong>r in most European countries, in ei<strong>the</strong>r untreated form or as a prepared fuel.<br />
It summary<br />
• Combustion is a well established technology and <strong>the</strong> main technical challenges have been<br />
addressed. Whatever <strong>the</strong> difficulties with <strong>the</strong> properties of <strong>the</strong> fuel engineers have developed<br />
robust solutions that have been proven <strong>to</strong> work commercially at most scales. As a result of this,<br />
combustion remains <strong>the</strong> default technology for heat and power against which all new, more<br />
innovative, options must be measured.<br />
• There seems <strong>to</strong> be a combustion solution for all waste fuels. A summary of combustion<br />
alternatives, <strong>the</strong>ir scales of operation and <strong>the</strong> range of feeds<strong>to</strong>cks for which <strong>the</strong>y are suitable is<br />
given in Table 66.<br />
• There remains however significant technical uncertainty surrounding <strong>the</strong> impact of <strong>the</strong><br />
composition of <strong>the</strong> waste on <strong>the</strong> performance of <strong>the</strong> heat exchange surfaces, particularly fouling<br />
and corrosion.<br />
• O<strong>the</strong>r barriers remain, such as <strong>the</strong> largely negative public perception of such sites in some<br />
countries, notably <strong>the</strong> UK.<br />
• A summary of risks and barriers is given in Table 66.<br />
• There are countless examples of combustion practice worldwide on which <strong>to</strong> draw.<br />
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Table 65 Overview of technology, scales of operation and fuel suitability<br />
Burner type Typical size<br />
MW fuel<br />
input<br />
Fuel<br />
quality<br />
Burner Technology<br />
grate (G) or<br />
Fluidised (F)<br />
Domestic 0.015 MW Logs and<br />
pellets<br />
G<br />
Commercial 0.2 MW Wood chip G<br />
upwards most<br />
qualities<br />
Small industrial 2 MW Most dry G<br />
upwards shredded<br />
materials<br />
Large industrial 20 MW Most dry G or F<br />
heat and CHP upwards shredded<br />
materials<br />
not<br />
necessarily<br />
dry<br />
MSW mass burn 20MW Minimally G<br />
incineration upwards sorted<br />
MSW<br />
Large cofiring 100 MW Most dry n/a<br />
upwards shredded<br />
materials.<br />
Preference<br />
for pellets<br />
SRF<br />
Waste Wood<br />
Clean Wood<br />
Domestic Pellet<br />
<br />
Industrial Pellet<br />
<br />
Unsorted Waste<br />
Wet Wastes<br />
Agricultural<br />
Residues<br />
T C Fuels
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Table 66 Risks and barriers <strong>to</strong> combustion<br />
Level of<br />
Risk<br />
Comment<br />
Technical Low <strong>to</strong> Many commercial installations, however <strong>the</strong> materials handling<br />
medium aspects have proved troublesome in <strong>the</strong> UK and <strong>the</strong>re is a lack of<br />
experience.<br />
Agricultural residues and poor quality wood fuels may give high<br />
ash contents that lead <strong>to</strong> problems with boiler fouling.<br />
Wastes regulated under WID will need extensive emissions<br />
moni<strong>to</strong>ring equipment.<br />
Social & Planning High High where used <strong>to</strong> produce electricity on a regional basis as it will<br />
be perceived as an incinera<strong>to</strong>r irrespective of its efficiency or<br />
recycling credentials.<br />
Financial Medium Track record of delays in planning for waste projects are a<br />
disincentive.<br />
Wood and agricultural residues are OK in normal circumstances<br />
but can be delays in urban areas<br />
Regula<strong>to</strong>ry Medium Receives subsidy via <strong>the</strong> Renewables Obligation.<br />
Waste incineration directive compliance is usually necessary.<br />
Co-firing waste in a utility boiler is difficult as it would require <strong>the</strong><br />
reclassification of <strong>the</strong> whole station as an incinera<strong>to</strong>r<br />
Fly ash may contain dioxin and be classed as hazardous waste.<br />
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9 Biological Processes<br />
The recycling initiatives targeting paper, cardboard, glass, plastic, metal and garden waste have also had<br />
<strong>the</strong> effect of increasing <strong>the</strong> food waste content (on a weight percent basis) of <strong>the</strong> remaining waste,<br />
particularly in <strong>the</strong> household waste stream. The food waste stream is now being increasingly targeted for<br />
separated collection and subsequent treatment <strong>by</strong> ei<strong>the</strong>r composting (using in-vessel composting) or<br />
anaerobic digestion. Ultimately this could result in up <strong>to</strong> 4 million <strong>to</strong>nnes per annum of food waste being<br />
sent <strong>to</strong> anaerobic digestion facilities which could generate bio-gas, potentially used for electricity<br />
generation or transport gases, and a solid digestate. We can also add <strong>to</strong> this <strong>the</strong> waste from food<br />
manufacture, distribution and sale and <strong>the</strong> substantial quantities of manures from agriculture. Bio-solids<br />
are a fur<strong>the</strong>r specialised form of wet waste that is used extensively for energy.<br />
9.1 Anaerobic Digestion (AD)<br />
Wet organic<br />
wastes<br />
Anaerobic<br />
digestion<br />
Process Description<br />
Anaerobic digestion is a natural biological process carried out <strong>by</strong> bacteria in low oxygen conditions.<br />
Organic material is converted in<strong>to</strong> biogas (a mixture of methane, carbon dioxide and o<strong>the</strong>r trace gases)<br />
and a solid residue or digestate.<br />
The biological reactions occur in three sequential steps. The organic waste is first broken down in<strong>to</strong><br />
simple sugars and amino acids <strong>by</strong> enzymes (hydrolysed). These <strong>the</strong>n ferment <strong>to</strong> produce fatty acids that<br />
are converted <strong>to</strong> hydrogen, carbon dioxide and acetate <strong>by</strong> ace<strong>to</strong>genic bacteria. Finally methanogenic<br />
bacteria produce biogas, a mixture of carbon dioxide (40%) and methane (60%) and o<strong>the</strong>r trace<br />
compounds. These biological processes operate in aqueous media, and hence are best suited <strong>to</strong> wet<br />
wastes.<br />
Anaerobic bacteria occur naturally and are commonly found in soils and deep water. They produce<br />
biological cultures that thrive within three temperature ranges, 7 - 24°C (psychrophilic), 35-39°C<br />
(mesophilic) and 55-60°C (<strong>the</strong>rmophilic).<br />
Table 67 Comparison of AD systems<br />
Biogas/<br />
Digestate<br />
Heat, power,<br />
grid gas<br />
Psychrophilic Mesophilic Thermophilic<br />
Optimal Temperature and<br />
Range ( o C)<br />
22 (7 - 25) 35 (25 - 42) 60 (49 - 72)<br />
Concentration V dilute Medium High<br />
Retention time (d) >50 20-40 5-20<br />
Gas generation rate Very slow Medium High<br />
Conversion of solid material Low Med <strong>to</strong> High High<br />
Construction Covered dam Steel or Steel or<br />
or lagoon concrete tank concrete tank
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Figure 17 Anaerobic Digester schematic 228<br />
In Europe more than 85% of plants operate within <strong>the</strong> mesophilic temperature range as <strong>the</strong> greatest<br />
number of suitable bacteria species operates at this temperature and are more <strong>to</strong>lerant of varying<br />
environmental conditions. 8% of AD systems in Europe operate in <strong>the</strong> <strong>the</strong>rmophilic range, mostly in<br />
Denmark as <strong>the</strong> <strong>the</strong>rmophillic temperature range is especially applied in centralised AD plants, as are<br />
common in Denmark. The advantage of such systems is <strong>the</strong> reduced time required and <strong>the</strong> greater level<br />
of sterilisation achieved of <strong>the</strong> digestate. The drawback of such systems is <strong>the</strong> greater heat requirement.<br />
Less than 5% of European systems operate in <strong>the</strong> psychrophilic range.<br />
AD systems used <strong>to</strong> treat food and farm wastes have been adapted from well established systems used<br />
<strong>to</strong> treat wastewater solid fractions (bio-solids). The digestion process takes place in sealed tanks<br />
(digesters) that are continuously mixed <strong>to</strong> ensure a uniform reaction rate.<br />
The amount of biogas produced using AD will vary depending on <strong>the</strong> volatile solids component of <strong>the</strong><br />
waste, <strong>the</strong> process design, such as reac<strong>to</strong>r residence times and operating temperature.<br />
228 Schematic taken from “AD biological cycle” page on <strong>the</strong> “Renewable Energy Association”, http://www.r-e-a.net/biofuels/biogas/anaerobic-<br />
digestion/ad-biological-cycle<br />
127
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Approximately a third of <strong>the</strong> heat production will be used <strong>to</strong> heat <strong>the</strong> digester vessel and maintain <strong>the</strong><br />
bacterial cultures at <strong>the</strong>ir optimum temperature. Fur<strong>the</strong>r heat may be necessary <strong>to</strong> pasteurise <strong>the</strong> solid<br />
residue before it can be sold as fertiliser or soil conditioner.<br />
Recently <strong>the</strong> National Grid Company has announced plans <strong>to</strong> encourage and develop projects that can<br />
inject natural gas quality biogas in<strong>to</strong> <strong>the</strong> National Gas Grid. This will involve <strong>the</strong> removal of carbon<br />
dioxide and any acid gas components <strong>by</strong> a combination of liquid scrubbing and adsorption technologies.<br />
The resulting cleaned gas will <strong>the</strong>n need <strong>to</strong> be compressed <strong>to</strong> ei<strong>the</strong>r transmission pressure of<br />
approximately 30bar or for smaller installations <strong>the</strong> low pressure distribution network at 3.0 and 0.5 bar. 229<br />
This concept has advantages for <strong>the</strong> opera<strong>to</strong>r of an AD plant if <strong>the</strong> incentives are sufficient, in that he will<br />
be able <strong>to</strong> sell <strong>the</strong> biogas in<strong>to</strong> <strong>the</strong> grid all year round. Heat sales from CHP are always problematic with<br />
space heat demand varying throughout <strong>the</strong> year.<br />
Understanding <strong>the</strong> potential for AD requires study on a spatial basis<br />
The technology relies on <strong>the</strong> collection, transport and disposal of large volumes of materials and at each<br />
stage of <strong>the</strong> process <strong>the</strong>re are constraints related <strong>to</strong> <strong>the</strong> location;<br />
• Wastes, crops and manure must be collected from a wide variety of sources and suppliers.<br />
• All feeds<strong>to</strong>cks are high water content, low energy density, and expensive <strong>to</strong> transport.<br />
• The installation must be sited where traffic density and odour will not be a problem and where<br />
<strong>the</strong>re is an electricity network connection and a heat cus<strong>to</strong>mer.<br />
• The unit produces almost as much material as digestate for transport and disposal as it receives<br />
as feeds<strong>to</strong>ck.<br />
• The business will also need access <strong>to</strong> suitable agricultural land within a reasonable transport<br />
radius <strong>to</strong> dispose of <strong>the</strong> digestate.<br />
An accurate estimate of potential would need <strong>to</strong> be carried out <strong>by</strong> mapping waste arisings, energy<br />
demand, gas grid and <strong>the</strong> digestate holding capacity of <strong>the</strong> land as a GIS study. ADAS have carried out<br />
work on <strong>the</strong> holding capacity but this has not as yet been extended <strong>to</strong> digestate.<br />
Feed s<strong>to</strong>cks suitable for anaerobic digestion<br />
Only high moisture content organic feeds<strong>to</strong>ck containing proteins, fats and carbohydrates can be<br />
processed success<strong>full</strong>y <strong>by</strong> anaerobic digestion. Cellulose and lignin digest far <strong>to</strong>o slowly so it is not<br />
suitable for paper and wood. This does mean that a large variety of wastes ranging from farm manures<br />
and bio-solids <strong>to</strong> catering wastes, food wastes, meat, and bone meal can be treated, however <strong>the</strong><br />
processing time (retention time) varies widely with <strong>the</strong> feeds<strong>to</strong>ck composition.<br />
The content of nitrogen compounds in <strong>the</strong> feeds<strong>to</strong>ck needs <strong>to</strong> be managed as <strong>the</strong>y are converted <strong>to</strong><br />
ammonia, which is <strong>to</strong>xic <strong>to</strong> anaerobic bacteria. The C:N ratio is also important as optimal growth of <strong>the</strong><br />
bacteria is achieved when this is 20-30:1.<br />
Food wastes and manures contain high levels of pathogens such as Salmonella and E.coli which must be<br />
destroyed during <strong>the</strong> digestion or during <strong>the</strong> pasteurisation process once digestion is complete.<br />
Scale of operation<br />
Typically digesters based in rural locations and using manures, food waste and energy crops will have an<br />
output of 300kWe, which represents approximately 40k <strong>to</strong>nnes per annum of wet feeds<strong>to</strong>ck, such as <strong>the</strong><br />
BioCycle Plant in South Shropshire and <strong>the</strong> Western Isles Integrated Waste Management Facility.<br />
Larger installations in semi-rural and urban locations that so far have focussed on supermarket and food<br />
processing waste may have an output up <strong>to</strong> 5MWe, for example <strong>the</strong> Wanlip Composting and AD Plant in<br />
Leicester. Sainsbury and PDM indicate that larger installations are unlikely. 230<br />
229 http://www.nationalgrid.com/corporate/Our+Responsibility/News/newsbiogas.htm<br />
230 Announcement <strong>by</strong> Sainsburys and PDM cooperation
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By-products<br />
The digestate can be used as a fertiliser and soil conditioner. Recent practice has been <strong>to</strong> strike an<br />
arrangement between <strong>the</strong> plant opera<strong>to</strong>r and local farms <strong>to</strong> allow <strong>the</strong> sp<strong>read</strong>ing of digestate <strong>to</strong> <strong>the</strong>ir land<br />
in return for treatment of manures.<br />
More recently <strong>the</strong> establishment of <strong>the</strong> Quality Pro<strong>to</strong>col for <strong>the</strong> digestate where it is <strong>to</strong> be sp<strong>read</strong> on<br />
agricultural or forestry land, is intended <strong>to</strong> facilitate <strong>the</strong> use of <strong>the</strong> digestate, although care will still need <strong>to</strong><br />
be taken in Nitrate Vulnerable Zones (NVZ), as discussed in <strong>the</strong> Pro<strong>to</strong>col, as 68% of arable land in<br />
England and 4% in Wales are designated <strong>to</strong> be within NVZs and <strong>the</strong>re are restrictions on how much<br />
nitrogen farmers can apply yearly. 231<br />
A recent example of <strong>the</strong> challenges increased volumes of digestate will create is given <strong>by</strong> Summerleaze’s<br />
Holsworthy site in Devon, which may only sp<strong>read</strong> <strong>the</strong> digestate on land between February and September<br />
during <strong>the</strong> grass growing season, as <strong>the</strong> surrounding farms are lives<strong>to</strong>ck ones. Therefore <strong>to</strong> operate at<br />
maximum capacity it must be able <strong>to</strong> s<strong>to</strong>re six months worth of digestate, <strong>to</strong>talling 42,000m 3 . Its current<br />
s<strong>to</strong>rage capacity is 15,000m 3 . 232<br />
Technology status<br />
Anaerobic digesters are very well established in Germany and o<strong>the</strong>r EU Member states, which have or<br />
have had favourable policy instruments.<br />
The table below provides <strong>the</strong> number of AD plants in EU countries and <strong>the</strong>ir electricity generation<br />
capacities in 2005. It is clear from <strong>the</strong> table that <strong>the</strong>re are a number of European countries in which <strong>the</strong><br />
uptake of AD, ei<strong>the</strong>r on-farm or centralised (CAD), <strong>by</strong> <strong>the</strong> agricultural industry has been much greater<br />
than in <strong>the</strong> UK, although it is also clear that Germany is quite exceptional.<br />
Table 68: Numbers of biogas plants in EU-countries producing electricity 233<br />
Country Agricultural AD<br />
plants<br />
Installed capacity MWe<br />
Austria 159<br />
29<br />
+150 <strong>to</strong> end 2007 + 40 <strong>to</strong> end 2007<br />
Belgium 6 12.3<br />
Denmark 58 on-farm<br />
20 CAD<br />
40<br />
France 3 n/a<br />
Germany > 3000 550<br />
Great Britain
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Some water companies are beginning <strong>to</strong> suggest <strong>the</strong> co-digestion of waste water and food waste<br />
alongside <strong>the</strong> digestion of bio-solids, such as <strong>the</strong> proposed site at Cumbernauld in Glasgow <strong>by</strong> Scottish<br />
Water. This arrangement could yield a higher biogas output as well as enabling a higher proportion of<br />
ROCs <strong>to</strong> be earned.<br />
Table 69 Risks Associated with Anaerobic Digestion<br />
Level of Risk Comment<br />
Technical Low <strong>to</strong> medium Established mature technology with operating commercial<br />
plant in existence.<br />
Limited experience in UK. Recent incentives may stretch<br />
UK suppliers.<br />
Poor reputation from early Holsworthy experience.<br />
Sensitive <strong>to</strong> feeds<strong>to</strong>ck composition, can be poisoned <strong>by</strong><br />
Social &<br />
Planning<br />
trace elements.<br />
Medium Not as divisive as an incinera<strong>to</strong>r but transport of slurries in<br />
rural areas is a major issue and focus for opposition, as<br />
may be large scale transport of food wastes.<br />
Financial Low Installations are being financed in <strong>the</strong> UK at present and<br />
fur<strong>the</strong>r experience should make this easier.<br />
Regula<strong>to</strong>ry Medium Receives subsidy via <strong>the</strong> Renewables Obligation at an<br />
enhanced rate of 2 ROCs under <strong>the</strong> banding<br />
arrangements.<br />
Policy may change under installations lifetime although<br />
current practice is <strong>to</strong> maintain <strong>the</strong> financial position of<br />
existing plant.<br />
The installation is classed as a waste management<br />
operation and subject <strong>to</strong> regulation as such which brings<br />
additional costs and responsibility.<br />
Digestate disposal is an important consideration and a<br />
change of rules could materially affect <strong>the</strong> operating costs<br />
of <strong>the</strong> installation or even prevent operation.<br />
9.1.1 Anaerobic Digestion of food waste from MSW<br />
The AD capacity for solid waste in <strong>the</strong> UK is growing. From a capacity of 135,000 <strong>to</strong>nnes in 2004, it<br />
increased <strong>to</strong> 277,000 <strong>to</strong>nnes through <strong>the</strong> addition of 6 new plants in 2005 and 2006. 234 This utilisation<br />
level is still very small compared <strong>to</strong> <strong>the</strong> waste potentially available <strong>to</strong> it. BERR estimates that <strong>the</strong> UK<br />
generates over 100 million <strong>to</strong>nnes of wastes that would be suitable for AD (90 million <strong>to</strong>nnes of<br />
agricultural wastes and 9 million <strong>to</strong>nnes of food waste).<br />
It is likely that utilisation levels will continue <strong>to</strong> grow, assisted <strong>by</strong> <strong>the</strong> reclassification of anaerobic digestate<br />
<strong>to</strong> no longer a waste product, so long as it is used as fertiliser on farmland.<br />
Defra intend for AD technology <strong>to</strong> be used throughout <strong>the</strong> UK <strong>by</strong> 2020, that it will be “making a significant<br />
and measurable contribution <strong>to</strong> our climate change and wider environmental objectives“ in part through<br />
<strong>the</strong> production of around 10-20TWh of energy. 235 For comparison, Drax power station in North Yorkshire,<br />
produces 25TWh annually, approximately 7% of <strong>the</strong> UK’s electricity mix. 236<br />
234 Anaerobic Digestion and its role in Transport Fuels, Renewable Energy Association, 2007.<br />
235 Anaerobic Digestion – Shared Goals, Defra, 2009, http://www.defra.gov.uk/environment/waste/ad/pdf/ad-sharedgoals-090217.pdf<br />
236 http://www.draxpower.com
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Almost all UK solid waste AD sites only utilise <strong>the</strong> biogas collected for <strong>the</strong> generation of electricity, and<br />
some heat required for <strong>the</strong> process. Little of <strong>the</strong> remaining heat is utilised, in external heating systems for<br />
example. In addition <strong>the</strong> biogas has <strong>the</strong> potential <strong>to</strong> be used in o<strong>the</strong>r ways, for example as a transport<br />
fuel. Current policy favours <strong>the</strong> production of electricity. 249 However, <strong>the</strong> Renewable Energy Strategy<br />
and increased targets for renewable heat in <strong>the</strong> UK may make it more feasible <strong>to</strong> inject gas in<strong>to</strong> <strong>the</strong> grid in<br />
<strong>the</strong> future.<br />
237, 238<br />
Current operational AD plants in <strong>the</strong> UK for solid waste are:<br />
• The BioCycle Plant in South Shropshire, run <strong>by</strong> Greenfinch, has been in operation since 2006<br />
and was built as a Defra Waste Technology Demonstra<strong>to</strong>r Project. The system now takes 4,100<br />
<strong>to</strong>nnes of kitchen only waste (originally it <strong>to</strong>ok kitchen and garden waste but <strong>the</strong> feeds<strong>to</strong>ck was<br />
<strong>to</strong>o contaminated) from households and commercial premises, converting it in<strong>to</strong> biogas and<br />
ultimately electricity with a 0.2kW output annually. 239<br />
• The Wanlip Composting and AD Plant in Leicester started operation in 2004 at <strong>the</strong> Severn Trent<br />
Sewage Works, using <strong>the</strong> organic component of MRF from MSW. 240 The waste goes through five<br />
processes: homogenisation, sand separation, hydrolysis, digestion, and decantation. The 5mm<br />
and smaller component is mixed <strong>to</strong> a slurry and pumped with air for 24 hours as an aerobic<br />
hydrolysis process <strong>the</strong>n <strong>the</strong> material undergoes an 18 day <strong>the</strong>rmophilic wet AD process, before<br />
being composted <strong>to</strong> produce CLO (compost like output) for fur<strong>the</strong>r use. The site accepts up <strong>to</strong><br />
50,000 <strong>to</strong>nnes per annum and has a 1.5MW potential output. 166<br />
• Summerleaze Ltd, at Holsworthy, Devon was <strong>the</strong> UK’s first centralised AD site, and opened in<br />
2005 for <strong>the</strong> digestion of agricultural slurries. It now handles organic wastes from bakeries and<br />
food processors, abat<strong>to</strong>irs, fish processors, cheese producers, biodiesel manufacturers and local<br />
councils in a system capable of processing 80,000 <strong>to</strong>nnes per annum currently. 241 The methane<br />
produced is used <strong>to</strong> generate 2.7MW, with approximately 10% of this used <strong>to</strong> run <strong>the</strong> plant and<br />
<strong>the</strong> remaining 90% exported <strong>to</strong> <strong>the</strong> National Grid. 242 One advantage of accepting food waste, is<br />
that it attracts higher gate fees than agricultural waste, encouraging <strong>the</strong> feasibility of <strong>the</strong> site.<br />
• As part of <strong>the</strong> Western Isles Integrated Waste Management Facility in Scotland a waste treatment<br />
centre incorporating recycling and MBT, <strong>the</strong> EarthTech AD plant, takes up <strong>to</strong> 12,000 <strong>to</strong>nes of<br />
biodegradable municipal waste and generates 0.24MW of electricity annually. This plant also has<br />
a CHP system incorporated in<strong>to</strong> it, which is used <strong>to</strong> heat <strong>the</strong> AD system itself.<br />
• At <strong>the</strong> Premier Waste AD site in Thornley, Durham, capable of processing 20,000 <strong>to</strong>nnes/yr of<br />
MSW, three concrete <strong>to</strong>wers are used as <strong>the</strong> AD vessels. This project is part of Defra’s<br />
Demonstra<strong>to</strong>r Project, and after some initial problems <strong>the</strong> project recommenced demonstra<strong>to</strong>r<br />
phase in mid 2008. 243<br />
Identifying a comprehensive list of currently functioning AD sites, and sites that will become operational in<br />
<strong>the</strong> future is difficult due <strong>to</strong> <strong>the</strong> level of interest in this area. Many potential sites are <strong>report</strong>ed as<br />
certainties, when in fact <strong>the</strong>y do not get as far as <strong>the</strong> planning stage, or markets change and a company<br />
decide not <strong>to</strong> go ahead with a site development. Also, many early AD sites have ceased operation for<br />
technical or financial reasons.<br />
A planned AD site is at Cumbernauld in Glasgow, for <strong>the</strong> treatment of 30,000 <strong>to</strong>nnes per annum of local<br />
food waste, <strong>by</strong> Scottish Water. The site is expected <strong>to</strong> be operating in 2010, <strong>to</strong> generate 1MW of<br />
237<br />
EU Requirement Approved Plants Report – Section VI Biogas Plants, 18 Feb 2009, http://www.defra.gov.uk/animalh/<strong>by</strong>prods/approvals/section6.pdf<br />
238<br />
ENDS Report 404, September 2008, p. 30-33, Biogas scents <strong>the</strong> sweet smell of success,<br />
239<br />
South Shropshire Biodigester, Ludlow Biocycle South Shropshire/Greenfinch Ltd, Information Sheet, 2008.<br />
240<br />
Anaerobic Digester at Wanlip, BiffaLeicester, http://biffaleicester.co.uk/about/composting.php?&printpage=true<br />
241<br />
Holsworthy Biogas Plant, Case Study 2, http://www.devon.gov.uk/renewable_energy_guide_case_study_2.pdf and “UK’s largest" AD plant<br />
permitted <strong>to</strong> take more food waste, 2008, http://www.letsrecycle.com/do/ecco.py/view_item?listid=37&listcatid=333&listitemid=10429<br />
242<br />
Andigestion, Holsworthy, http://www.andigestion.co.uk/content/holsworthy<br />
243<br />
Defra Factsheet, Premier, http://www.defra.gov.uk/environment/waste/wip/newtech/dem-programme/pdf/Premier.pdf<br />
131
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electricity and 1MW of heat. Meanwhile a 75,000 <strong>to</strong>nnes per annum site has planning permission in<br />
Bedding<strong>to</strong>n for processing kitchen waste and <strong>the</strong> organic component of <strong>the</strong> systems al<strong>read</strong>y on <strong>the</strong> site,<br />
generating 2MW of electricity a year.<br />
A demonstra<strong>to</strong>r site run <strong>by</strong> Organic Power in Somerset has been working <strong>to</strong> convert food, animal and<br />
o<strong>the</strong>r organic wastes <strong>to</strong> biomethane through AD for use as a transport fuel for a number of years. The<br />
biomethane is converted <strong>to</strong> CNG (compressed natural gas) with <strong>the</strong> addition of a small amount of<br />
biohydrogen <strong>to</strong> ensure optimum combustion in CNG vehicles. 244<br />
International Situation<br />
One exemplar example of <strong>the</strong> use of large scale use of AD for MSW is <strong>the</strong> Brecht II facility in Belgium,<br />
which began operation in 2000 with a capacity of 50,000 <strong>to</strong>nnes per annum. The feeds<strong>to</strong>ck for <strong>the</strong> plant<br />
is mainly organics such as garden, kitchen and food waste <strong>to</strong> which nappies, non-recyclable paper or<br />
cardboard can be added. The facility processes <strong>the</strong> waste from <strong>the</strong> municipalities around <strong>the</strong> city of<br />
Antwerp. During 2005, 7.4 million m 3 of biogas was produced, used <strong>to</strong> generate 9.1 GWh of electricity.<br />
The plant also produces 20,000 <strong>to</strong>nnes of compost which meets <strong>the</strong> Flemish regulations for high quality<br />
soil amendment.<br />
9.1.2 Anaerobic Digestion of Commercial Waste<br />
Many food producers, including <strong>the</strong> major supermarket chains, have stated <strong>the</strong>ir wish <strong>to</strong> use waste<br />
diversion methods for <strong>the</strong>ir food wastes. Although <strong>the</strong>re are only two strictly commercial food waste sites<br />
operational at <strong>the</strong> moment (and one of <strong>the</strong>se is a demonstra<strong>to</strong>r project), it is likely that this number will<br />
increase in <strong>the</strong> very near future, due <strong>to</strong> <strong>the</strong> significant rise in interest in this process.<br />
The demonstration scale anaerobic digestion facility exists at Waterbeach, Cambridge Research Park,<br />
near Cambridge. Trials of commercial waste materials such as agricultural, biodegradable industrial,<br />
kitchen and animal <strong>by</strong>-product wastes are being conducted at <strong>the</strong> site which can handle up <strong>to</strong> 17 <strong>to</strong>nnes<br />
of material per day. 245<br />
The Twinwoods Biogen Greenfinch site in Mil<strong>to</strong>n Earnest north of Bedford accepts up <strong>to</strong> 42,000 <strong>to</strong>nnes of<br />
commercial food waste combined with 12,000 <strong>to</strong>nnes of pig slurry each year and converts it <strong>to</strong> 1MW of<br />
electricity, 1.65MW of heat energy which is largely consumed <strong>by</strong> <strong>the</strong> process itself, and 32,000 <strong>to</strong>nnes of<br />
bio-fertiliser.<br />
A fur<strong>the</strong>r commercial food waste site is at Westwood, Bedford, Northamp<strong>to</strong>nshire, <strong>to</strong> be operated <strong>by</strong><br />
Biogen Greenfinch. It is due <strong>to</strong> be operational in 2009 and will be able <strong>to</strong> process 45,000 <strong>to</strong>nnes of food<br />
waste each year, generating 1.5MW of electricity and 35,000 of biofertiliser. The supermarket company<br />
Sainsbury’s recently announced that <strong>the</strong>y were investing in his facility, with <strong>the</strong> intention that<br />
supermarkets close <strong>to</strong> <strong>the</strong> site and its near<strong>by</strong> distribution centre will use <strong>the</strong> process. 207<br />
Ano<strong>the</strong>r potential AD site in Doncaster has been granted permission, this site will process 45,000 <strong>to</strong>nnes<br />
of food waste each year for Prosper De Mulder (PDM), a commercial food waste firm and Sainsbury’s has<br />
al<strong>read</strong>y expressed a strong interest. It is expected <strong>to</strong> generate 2MW of electricity.<br />
Drinks firm Diageo has announced its plans <strong>to</strong> construct an AD facility at its Cameronbridge distillery in<br />
Fife. 238<br />
244 Organic Power Website, http://www.organic-power.co.uk/press_articles.aspx<br />
245 Waterbeach AD Site, http://www.andigestion.co.uk/content/waterbeach
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International Situation<br />
Identifying sites that use AD <strong>to</strong> dispose of commercial organic wastes is difficult as many are simply<br />
recorded as accepting ‘biowaste’ without fur<strong>the</strong>r details. Austria cites several AD sites that accept only<br />
catering waste, including <strong>the</strong> Bruck a.d. Leitha site (20,000 <strong>to</strong>nnes p.a.), <strong>the</strong> Hagenbrunn site (20,000<br />
<strong>to</strong>nnes/yr) and <strong>the</strong> Heiligenkreuz am Vase site (12,000 <strong>to</strong>nnes p.a.). 246<br />
Bellisimo, an American frozen meal producer is constructing its second 5.25 US million gallon digester at<br />
its production facility in rural Ohio, one of <strong>the</strong> first American companies <strong>to</strong> invest in this technology. 247<br />
The system’s output will be used within <strong>the</strong> fac<strong>to</strong>ry.<br />
9.1.3 Anaerobic Digestion of Biosolids<br />
The digestion of biosolids is a special case of anaerobic digestion. Sewage gas is <strong>the</strong> result of controlled<br />
anaerobic digestion (AD) occurring within a sewage handling facility, with 66% of sewage generated<br />
al<strong>read</strong>y treated <strong>by</strong> AD in <strong>the</strong> UK in 220 sludge digesters. 248,249 The process occurs in a well mixed,<br />
heated reac<strong>to</strong>r but <strong>the</strong> reactions take some time due <strong>to</strong> <strong>the</strong> relatively low concentration of volatile solids.<br />
Sewage gas feed s<strong>to</strong>ck is <strong>the</strong> lef<strong>to</strong>ver sludge from <strong>the</strong> activated sludge process used at sewage<br />
treatment plants. Much of <strong>the</strong> biogas generated from this process is used <strong>to</strong> supply <strong>the</strong> needs of <strong>the</strong><br />
processing plant. Water UK estimate that 60% of <strong>the</strong> biogas produced is collected and used <strong>to</strong> generate<br />
renewable heat and power <strong>by</strong> CHP engines, <strong>to</strong>talling 88MW of electricity. 249 However this represents<br />
only 14% of <strong>the</strong> energy requirements of <strong>the</strong> industry, as <strong>the</strong> water processing industry is <strong>the</strong> UK’s fourth<br />
most energy-intensive industry, accounting for approximately 3% of <strong>the</strong> UK’s electricity consumption. 250<br />
Defra has set <strong>the</strong> aim for <strong>the</strong> water companies <strong>to</strong> supply 20% of <strong>the</strong>ir energy needs from renewable<br />
sources, such as <strong>the</strong>ir in house AD processes, <strong>by</strong> 2020. 251 As of April 2009 water companies earn <strong>the</strong><br />
reduced 0.5 ROCs per MWh of energy <strong>the</strong>y generate from biogas. 249 Some water companies are<br />
considering <strong>the</strong> use of food and o<strong>the</strong>r wastes as additional feeds<strong>to</strong>cks in response <strong>to</strong> <strong>the</strong> enhanced level<br />
of incentives given <strong>to</strong> anaerobic digestion in <strong>the</strong> reformed renewable obligation. 248<br />
Many water companies have pledged <strong>to</strong> reduce <strong>the</strong>ir carbon footprints and one way of doing this would<br />
be through achieving a greater efficiency of harvesting <strong>the</strong> biogas. For example Anglian Water has<br />
committed <strong>to</strong> increase <strong>the</strong> proportion of its energy met from biogas and wind power from 2% <strong>to</strong> 20% <strong>by</strong><br />
2010; Sou<strong>the</strong>rn Water aims <strong>to</strong> increase renewable generation <strong>to</strong> 20% <strong>by</strong> 2020, up from 10% in 2008;<br />
Thames Water aims <strong>to</strong> increase its renewable generation from its current level of 14% <strong>to</strong> 18% <strong>by</strong> 2020;<br />
and United Utilities intends <strong>to</strong> increase it in house electricity generation <strong>by</strong> 8% <strong>by</strong> 2012. 249<br />
9.1.4 Anaerobic Digestion of Agricultural wastes<br />
Anaerobic digestion of animal wastes is an established method of dealing with significant quantities of<br />
animal slurries and residues. Controlled anaerobic digestion of such residues, with collection and<br />
utilisation of <strong>the</strong> bio-methane produced is less well established in <strong>the</strong> UK.<br />
The bio methane potential (Bo) of manure and slurry is <strong>the</strong> methane producing potential of <strong>the</strong> manure,<br />
expressed as cubic meters (m 3 ) of methane per kilogram of Volatile Solids (VS), also referred <strong>to</strong> as <strong>the</strong><br />
maximum methane producing capacity for <strong>the</strong> manure. It varies <strong>by</strong> animal species and diet. Table 70<br />
246<br />
IEA Biogas, Plant List, http://www.iea-biogas.net/anlagelisten/Plantlist_08.pdf<br />
247<br />
Bellisimo Foods, http://www.bellisiofoods.com/sustainability.html, Turn Food Waste in<strong>to</strong> Energy, Environmental Defence Fund,<br />
http://innovation.edf.org/page.cfm?tagid=1339 .<br />
248<br />
Water UK, Water Industry at <strong>the</strong> hub of anaerobic digestion, 17/02/09, http://www.water.org.uk/home/news/press-releases/ad-vision<br />
249<br />
ENDS Report 404, September 2008, p.30-33, Biogas Scents <strong>the</strong> Sweet Smell of Success.<br />
250<br />
ENDS Report 401, June 2008, p.32-36, Water Companies call in <strong>the</strong> Carbon Accountants.<br />
251<br />
Defra (2009) Anaerobic Digestion – shared goals available www.defra.gov.uk<br />
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describes <strong>the</strong> characteristics previous discussed in <strong>the</strong> agricultural residues section, but also details <strong>the</strong><br />
bio-methane potential of <strong>the</strong> material.<br />
Table 70 Animal manure generation characteristics<br />
Bio Methane: cubic meters (m 3 ) of methane per kilogram of Volatile Solids (VS).<br />
Animal Proportion of<br />
<strong>the</strong> year<br />
housed<br />
Proportion of<br />
waste<br />
collected as<br />
slurry<br />
Volatile<br />
Solids<br />
kg/head/day<br />
Bio methane<br />
potential<br />
m 3 CH4/kg VS<br />
Dairy cow 59% 66% 3.48 0.24<br />
O<strong>the</strong>r cattle<br />
(excl. calves)<br />
50% 18% 2.7 0.17<br />
Calves 45% 0% 1.46 0.17<br />
Dry sow 100% 35% 0.63 0.45<br />
Sows plus<br />
litters<br />
100% 75% 0.63 0.45<br />
Fattening pig<br />
(20 – 130kg)<br />
90% 33% 0.49 0.45<br />
Weaners<br />
(
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• The AD site at Bank Farm in Wales was one of <strong>the</strong> first on farm AD sites in <strong>the</strong> UK, becoming<br />
operational in 1991 with a capacity <strong>to</strong> treat 790m 3 . It has recently been converted <strong>to</strong> generate<br />
electricity from <strong>the</strong> methane produced on site.<br />
A proposed AD site at Piddlehin<strong>to</strong>n in Dorset has recently been granted panning permission. It is<br />
expected that this site will accept 35,000 <strong>to</strong>nnes per annum of food waste, green waste and pig slurry,<br />
and generate electricity and a biofertiliser. 255<br />
Fur<strong>the</strong>r sites that are <strong>full</strong>y consented but are not yet operational are Eye Airfield in Suffolk which is<br />
expected <strong>to</strong> have an output of 1.05 MW, Dimmer in Somerset anticipated <strong>to</strong> have a 3MW output, and<br />
Lowe Farm with a predicted output of 0.5MW.<br />
International Situation<br />
Digestion of agricultural manure and slurries <strong>by</strong> controlled AD are well utilised in some European<br />
Countries. Centralised Anaerobic Digestion was first used in Denmark in <strong>the</strong> late 1980s. Its appeal is<br />
growing rapidly and its use is now common in Germany and <strong>to</strong> some extent in Sweden and Italy.<br />
Production of biogas in <strong>the</strong> EU 27 has risen steadily over <strong>the</strong> last few years and <strong>to</strong>talled 62 TWh in 2006<br />
(once again, compare this against Drax power station output of 25TWh p.a.). 256<br />
It is worth noting that <strong>the</strong> use of AD systems across Europe can be split in<strong>to</strong> two distinct types. Sou<strong>the</strong>rn<br />
countries such as Italy, Portugal and Spain use it as a waste-water treatment technology because <strong>the</strong><br />
waste is collected at high water content levels, so containing low solid residues. While in nor<strong>the</strong>rn<br />
European countries such as Germany, Denmark and Switzerland <strong>the</strong> water content is considerably lower,<br />
<strong>the</strong> solid content correspondingly higher and <strong>the</strong> systems optimized for fertilizer production. 257<br />
Denmark<br />
There are over 20 centralised plants operating in Denmark, with a fur<strong>the</strong>r 20 farm scale operations.<br />
Feeds<strong>to</strong>cks are mainly pig and cattle manure, but also include waste food, fat sludge and brewery<br />
wastes. 257<br />
• The Vester Hjermitslev was <strong>the</strong> first centralized co-digestion plant in Denmark, built in 1984 and<br />
supplied <strong>by</strong> 5 cattle and pig farms which supply slurry <strong>to</strong> <strong>the</strong> plant, <strong>to</strong>ge<strong>the</strong>r with a small amount<br />
of fish processing waste, tannery waste and waste fodder. The process operates at 37°C, with a<br />
sanitation stage of 4½ hours at 57°C. Once this is completed <strong>the</strong> biogas can be utilised in <strong>the</strong><br />
onsite CHP unit in <strong>the</strong> 2 mo<strong>to</strong>rs (840 kW +770 kW). Any overproduction is used in a gas boiler<br />
(250 kW). 257<br />
• The Ribe Biogas Plant began operating in 1990 and is supplied <strong>by</strong> 69 lives<strong>to</strong>ck farms (cattle, pig,<br />
poultry, mink), <strong>to</strong>ge<strong>the</strong>r with waste from abat<strong>to</strong>irs, food and fish waste. The facility is owned <strong>by</strong><br />
<strong>the</strong> supplying farmers, a food processing company that supplies organic waste <strong>to</strong> <strong>the</strong> plant, <strong>the</strong><br />
regional power company and two investment companies. The site operates at a digestion<br />
temperature of 53°C, and <strong>the</strong> minimum retention time of 4 hours ensures <strong>the</strong> digestate is<br />
sanitised, and is <strong>the</strong>n used <strong>by</strong> <strong>the</strong> slurry providers as a liquid fertiliser, or sold as surplus. The<br />
biogas produced <strong>by</strong> <strong>the</strong> system is piped <strong>to</strong> a CHP pant at Ribe, which generates electricity and<br />
heat for <strong>the</strong> city using a mix of bio gas and natural gas. 257<br />
• Nysted biogas plant was built as an extension <strong>to</strong> <strong>the</strong> al<strong>read</strong>y established Hashøj biogas plant.<br />
Slurry and manure is received from 36 farms and is mixed with waste from <strong>the</strong> sugar industry, <strong>the</strong><br />
medicinal industry, tanneries, an abat<strong>to</strong>ir as well as fruit and vegetable waste and held at 38°C,<br />
with a sanitation phase consisting of 8 hours at 55°C. The plant is also able <strong>to</strong> process source<br />
separated household waste. The biogas produced is used in a 2300 kW engine <strong>to</strong> generate<br />
electricity for <strong>the</strong> grid and heat for 150 cus<strong>to</strong>mers. 257<br />
255 Green Light for £5.5 Million Dorset AD Facility, 16.03.09, LetsRecycle.com,<br />
http://www.letsrecycle.com/do/ecco.py/view_item?listid=37&listcatid=217&listitemid=31237<br />
256 Danish Centralised Biogas Plants – Plant Descriptions, Bioenergy Department, University of Sou<strong>the</strong>rn Denmark, 2000.<br />
257 Environmental Aspects of Biogas Technology, B. Klingler, German Biogas Association, AD-NETT.<br />
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Germany<br />
Germany has <strong>by</strong> far <strong>the</strong> greatest number of AD sites in Europe. The 2.4M<strong>to</strong>e p.a. of biogas produced<br />
from over 3,700 plants is largely used in co-generation facilities, and generated 1,270 MW of electricity in<br />
2007. 258 Estimates are that Germany will exceed 3,000 MW <strong>by</strong> 2020, 259 despite <strong>the</strong> annual increment<br />
slowing from 800 units per annum in 2006 <strong>to</strong> 250 per annum in 2007. This slowing is felt <strong>to</strong> be due <strong>to</strong><br />
higher energy crop prices and a doubling in <strong>the</strong> equipment costs.<br />
The incentives system of producing renewable electricity in Germany has largely favoured <strong>the</strong> uptake of<br />
on-farm AD systems <strong>by</strong> farmers seeking <strong>to</strong> enhance <strong>the</strong>ir income but <strong>the</strong> scale of operation is increasing<br />
and <strong>the</strong>re are <strong>report</strong>s of very large plants now being built specifically for injection of gas in<strong>to</strong> <strong>the</strong> grid.<br />
For small-scale AD <strong>the</strong> additional tariff is nearly twice that of renewable obligation certificates in <strong>the</strong> UK,<br />
with extra available for CHP and for cultivated biomass feeds<strong>to</strong>ck. Driven <strong>by</strong> this market, technological<br />
advances made in Germany enable dry fermentation and co-digestion with energy crops, increasing <strong>the</strong><br />
potential for biogas production. The industry is also backed up <strong>by</strong> a large number of suppliers and good<br />
technical support.<br />
Figure 18 German AD sites and <strong>the</strong> electrical output 260<br />
In Germany over 200 companies are offering services in connection with biogas technology, e.g.<br />
consulting, planning, manufacturing and delivery of parts and components (pumps, stirrers, engines,<br />
tanks) as well as servicing. It is estimated that <strong>to</strong>ge<strong>the</strong>r with <strong>the</strong> operating staff 8,000 jobs are depending<br />
on <strong>the</strong> services revolving around biogas technology so far.<br />
We give below a small selection of interesting examples from Germany illustrating <strong>the</strong> communal<br />
character of many installations and <strong>the</strong> large scale which is now possible.<br />
• The biogas plant in Reichenbach, in Saxony became operational in 2007, producing 845kW from<br />
liquid manure from <strong>the</strong> local farming cooperative. The waste heat produced is sold <strong>to</strong> <strong>the</strong> local<br />
hospital.<br />
• Jühnde (population 750, 220 households), near Göttingen became <strong>the</strong> first bioenergy village in<br />
Germany. 261 Ten agricultural businesses supply <strong>the</strong> 700kW electrical and 740kW heat Hasse<br />
biogas plant with slurry, grass, maize silage and garden waste, which <strong>to</strong>ge<strong>the</strong>r with <strong>the</strong> connected<br />
258 Renewables made in Germany, http://www.renewables-made-in-germany.com/en<br />
259 http://www.renewables-made-in-germany.com/en/biogas/<br />
260 Source German Biogas Association<br />
261 The First Bioenergy Village in Germany, http://www.german-renewable-energy.com/Renewables/Navigation/Englisch/Biomasse/case-<br />
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heat and power genera<strong>to</strong>r (powered with local biomass) generate enough electricity and heat <strong>to</strong><br />
supply <strong>the</strong> requirements of <strong>the</strong> village.<br />
• Germany’s first industrial sized biogas plant opened in 2008, on <strong>the</strong> Klarsee industrial estate in<br />
Penkun, Mecklenburg-Western Pomerania on <strong>the</strong> German-Polish border. 262 The site takes silage<br />
and manure (<strong>to</strong>ge<strong>the</strong>r with maize and o<strong>the</strong>r cereals) from local farms and creates slurry <strong>to</strong> be<br />
processed <strong>by</strong> 40 independent digesters. The methane produced is converted in<strong>to</strong> electricity, with<br />
<strong>the</strong> plant capable of producing a 20MW output.<br />
Sweden<br />
Sweden is well known for having created several examples of a biogas network used <strong>to</strong> power vehicles.<br />
In Linköping a biogas plant was built in 1997, treating 100,000 <strong>to</strong>nnes p.a. or animal slaughter-house<br />
waste and industrial organic waste and producing 7.7 million m 3 per annum of upgraded biogas. This<br />
biogas is <strong>the</strong>n used <strong>to</strong> power <strong>the</strong> city buses plus several light and heavy vehicles, as well as a number of<br />
private vehicles. 263 Sweden is well placed <strong>to</strong> develop such systems as <strong>the</strong> country had a considerable<br />
number of gas powered vehicles <strong>to</strong> begin with (13,500 in 2008, 110 gas filling stations 264 ) , and <strong>the</strong> gas<br />
distribution network is not that extensive, for example it does not reach Linköping. Ano<strong>the</strong>r <strong>to</strong>wn in<br />
Sweden, Laholm, has been injecting <strong>the</strong> biogas its AD digester produces in<strong>to</strong> <strong>the</strong> local natural gas grid<br />
since 2001. The digester accepts 48,000 <strong>to</strong>nnes p.a. of agricultural manures and industrial organic<br />
waste. 265<br />
A similar project in <strong>the</strong> UK, undertaken jointly <strong>by</strong> Sita UK, Gasrec and Boc, announced in June 2008 that<br />
<strong>the</strong>y had produced a biomethane transport fuel from landfill gas at <strong>the</strong> Sita UK landfill site in Albury,<br />
Surrey. 266 This landfill site produces 2,300m 3 of landfill gas per hour, and <strong>the</strong> intention is <strong>to</strong> use this <strong>to</strong><br />
produce 5,000 <strong>to</strong>nnes of biomethane for use <strong>by</strong> <strong>the</strong> site opera<strong>to</strong>r, <strong>by</strong> haulage firm Hardstaff Group, <strong>by</strong> a<br />
Sainsbury’s delivery truck and <strong>by</strong> a street cleaning vehicle in Camden <strong>to</strong> give feedback on a range of<br />
uses. The process upgrades <strong>the</strong> landfill gas <strong>by</strong> dewatering, <strong>the</strong>n removal of hydrogen sulphide, carbon<br />
dioxide and nitrogen, selectively capturing 85% of <strong>the</strong> methane processed, at 95% purity. The gas<br />
produced is <strong>the</strong>n liquefied for use. Potentially this fuel could also be used in CHP plants.<br />
9.2 Composting - an alternative <strong>to</strong> Anaerobic Digestion<br />
Process Description<br />
Composting is <strong>the</strong> aerobic decomposition <strong>by</strong> micro-organisms of biodegradable material <strong>to</strong> produce a<br />
residue - compost. It is a process primarily used for <strong>read</strong>ily degradable organic materials, such as source<br />
separated green garden wastes and kitchen wastes.<br />
The waste is degraded <strong>by</strong> "heat-loving" micro-organisms. This is a biological process that oxidises <strong>the</strong><br />
organic matter <strong>to</strong> break it down <strong>to</strong> a more simple form. A high temperature within <strong>the</strong> process is important<br />
<strong>to</strong> eliminate pathogens that may be present in <strong>the</strong> source materials.<br />
The composting operations must ensure that <strong>the</strong> micro-organisms are kept supplied with moisture,<br />
oxygen, food and nutrients and that conditions such as temperature remain in <strong>the</strong> optimum range. A<br />
large number of procedures and engineered solutions have been developed <strong>to</strong> achieve <strong>the</strong>se objectives<br />
for <strong>the</strong> treatment of organic wastes.<br />
262 Industrial-scale production in world's largest biogas plant, Federal Ministry of Economics and Technology, Germany.<br />
263 100% Biogas for Urban Transport in Linkoping, Sweden, IEA Biogas Network.<br />
264 Renewables target <strong>to</strong> be extended <strong>to</strong> at least 35%, ENDS Report 402, pp 38-39.<br />
265 Injection of Biogas in<strong>to</strong> <strong>the</strong> Natural Gas Grid in Laholm, Sweden, IEA Biogas Network, http://www.ieabiogas.net/Dokumente/casestudies/sucess_laholm.pdf<br />
266 Gasrec, boc and SITA UK announce first fuel production at biomethane project in Albury, Surrey, Site Press Release 2008.<br />
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Open Composting Systems<br />
Most compost is generated through open air techniques, which places <strong>the</strong> organic waste in piles exposed<br />
<strong>to</strong> <strong>the</strong> air. The waste is commonly formed in<strong>to</strong> elongated triangular piles that are called windrows, which<br />
allow optimum exposure <strong>to</strong> <strong>the</strong> atmosphere whilst minimising <strong>the</strong> land area taken up. Once <strong>the</strong> waste is<br />
prepared for composting <strong>the</strong> principal control mechanism for <strong>the</strong> process is <strong>the</strong> air requirement of <strong>the</strong><br />
micro-organisms and <strong>the</strong> dissipation of <strong>the</strong> heat generated. Introduction of air in<strong>to</strong> <strong>the</strong> waste can be<br />
achieved ei<strong>the</strong>r though active pumping of air in<strong>to</strong> <strong>the</strong> waste or through <strong>the</strong> mechanical lifting and mixing of<br />
<strong>the</strong> waste <strong>to</strong> introduce air in<strong>to</strong> <strong>the</strong> pile. These two approaches are called static aerated pile and turned<br />
windrow.<br />
Windrow composting is well established in <strong>the</strong> UK with a large number of facilities treating source<br />
separated garden waste. Such systems for green wastes are typically quoted at between £20 and £25/t<br />
of waste treated although <strong>the</strong>re is strong regional effects due <strong>to</strong> <strong>the</strong> potential for markets of <strong>the</strong> compost.<br />
In-Vessel Composting Systems<br />
Reac<strong>to</strong>r or enclosed composting is a relatively new composting development that provides a faster active<br />
biodegradation process, reducing <strong>the</strong> area required. The use of a ‘closed’ vessel allows much greater<br />
control over <strong>the</strong> process and this helps both with <strong>the</strong> speed of <strong>the</strong> process but also <strong>the</strong> consistency<br />
(hence quality) of <strong>the</strong> compost product.<br />
The reac<strong>to</strong>rs come in a variety of forms and have varying degrees of au<strong>to</strong>mation. However, <strong>the</strong> basis of<br />
reac<strong>to</strong>r composting is that materials are enclosed in a drum, silo, or similar structure and air is injected<br />
in<strong>to</strong> <strong>the</strong> composting material <strong>to</strong> maintain <strong>the</strong> optimum conditions for composting.<br />
Following <strong>the</strong> foot and mouth outbreak in 2001, any waste which contains or could contain meat or meat<br />
products has <strong>to</strong> be treated at a certain temperature for a minimum period of time, thus any source<br />
separated waste which includes <strong>the</strong> collection of kitchen waste from households, would need <strong>to</strong> be<br />
composted in an in-vessel system.<br />
In-vessel composting facilities are not as well established, with less than 20 operational in <strong>the</strong> UK. These<br />
systems are more expensive than windrow systems with potential gate fees in <strong>the</strong> range £35-£50/t of<br />
waste treated. However, in Europe <strong>the</strong> number of facilities is large with in-vessel composting becoming<br />
<strong>the</strong> norm for organic wastes o<strong>the</strong>r than green garden wastes.<br />
Outputs<br />
Compost is stabilised organic material consisting of <strong>the</strong> refrac<strong>to</strong>ry and slowly degradable cellulosic<br />
components. The main use of this compost is as a soil improver.<br />
The quality of <strong>the</strong> compost is largely determined <strong>by</strong> <strong>the</strong> feeds<strong>to</strong>ck provided <strong>to</strong> <strong>the</strong> process. Relatively<br />
uncontaminated feeds<strong>to</strong>cks will give rise <strong>to</strong> uncontaminated products and <strong>the</strong>se are generally composted<br />
from source-separated materials. The residues from <strong>the</strong> composting process are those materials that do<br />
not <strong>read</strong>ily degrade, such as wood and <strong>the</strong>se can ei<strong>the</strong>r be returned <strong>to</strong> <strong>the</strong> front of <strong>the</strong> process <strong>to</strong> be<br />
shredded or <strong>the</strong>y can be disposed of.<br />
The ratio of soil improver product <strong>to</strong> reject fractions will vary markedly with <strong>the</strong> feeds<strong>to</strong>ck and process but<br />
typically <strong>the</strong> product material might only be 50 <strong>to</strong> 60% of <strong>the</strong> incoming waste with 15-30% loss of mass<br />
through <strong>the</strong> biodegradation for source separated materials whilst residual (mixed waste) compost may<br />
only generate 10-20% compost product with up <strong>to</strong> 60% being reject <strong>to</strong> landfill.<br />
9.2.1 Composting of MSW<br />
The use of composting schemes is growing, especially as <strong>the</strong> organic fraction of MSW <strong>to</strong> landfill must be<br />
reduced. While composting does not produce ei<strong>the</strong>r energy or fuels from waste, it does produce a viable<br />
product as an output, and it gives an indication of <strong>the</strong> proportion of organic material, largely from MSW,<br />
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In 2006-07 3.6M <strong>to</strong>nnes of source segregated waste was composted, a 5% increase on <strong>the</strong> previous<br />
year. 267 The vast majority of this waste is from MSW, and of this 48% was from civic amenity sites while<br />
46% was from kerbside collections.<br />
There are many composting sites in <strong>the</strong> UK, of varying sizes, types and longevity. Identifying a complete<br />
list of sites is difficult as many waste opera<strong>to</strong>rs are experimenting with this process, and so sites are<br />
developing rapidly at <strong>the</strong> moment, as decisions are taken on whe<strong>the</strong>r <strong>to</strong> pursue this disposal method.<br />
Some of <strong>the</strong> better known examples of large scale composting sites in <strong>the</strong> UK are:<br />
Table 71 Large scale composting examples in <strong>the</strong> UK<br />
Name and Location Volume Operational<br />
Glasgow Fruit Market,<br />
Glasgow 268<br />
2,000 <strong>to</strong>nnes p.a.<br />
2005<br />
Council run and output is<br />
sold.<br />
Twycross Zoo,<br />
Warwickshire 269<br />
Lynnbot<strong>to</strong>m, Isle of<br />
Wight 270<br />
St. Ives,<br />
Cambridgeshire 271<br />
Whar<strong>to</strong>n,<br />
Herefordshire 272 *<br />
Enclosed composting of waste<br />
fruit, vegetables, paper, card and<br />
pallet wood<br />
800 <strong>to</strong>nnes p.a.<br />
Enclosed composting of animal<br />
wastes and garden waste.<br />
Up <strong>to</strong> 60 <strong>to</strong>nnes per day<br />
Originally composting of garden<br />
waste in windorws. More recently<br />
taking food waste in-vessel.<br />
100,000 <strong>to</strong>nnes p.a.<br />
Conversion of kitchen and green<br />
waste in 4 composting tunnels, 2<br />
of which are part of Defra<br />
Demonstra<strong>to</strong>r Programme.<br />
10,000 <strong>to</strong>nnes p.a.<br />
In vessel anaerobic digestion<br />
technique <strong>to</strong> compost garden and<br />
kitchen waste. Also one of <strong>the</strong><br />
Defra Demonstra<strong>to</strong>r Programmes.<br />
2008<br />
1992<br />
2002<br />
Parham, Suffolk 273 * Site takes garden and food<br />
waste, shredded paper and<br />
cardboard, from Suffolk Coastal<br />
District Council<br />
2006<br />
* The operating company went in<strong>to</strong> administration in February 2009, at which point <strong>the</strong> site in Parham was<br />
taken over <strong>by</strong> Country Style group and continues <strong>to</strong> operate.<br />
267 Compost Information Sheet, Waste Online, http://www.wasteonline.org.uk/resources/InformationSheets/Compost.htm<br />
268 Chronicle of Glasgow’s Fish, Fruit and Flower Markets,<br />
http://www.glasgow.gov.uk/en/Business/Markets/chronicleofglasgowsfishfruitvegetableandflowermarket.htm<br />
269 Twycross Zoo Recycles Poo! http://www.twycrosszoo.com/news/currentnews.htm<br />
270 Lynnbot<strong>to</strong>m Composting Facility, http://www.wrightenvironmental.com/pdf/IsleofWight_print.pdf<br />
271 Envar, Services, Composting, http://www.envar.co.uk/services/composting.html?menu_pos=services<br />
272 Bioganix Research Limited, Defra Factsheet, http://www.defra.gov.uk/environment/waste/wip/newtech/dem-programme/pdf/Bioganix.pdf<br />
273 Greenprint Forum and Green Issues Task Group visit <strong>the</strong> Parham Compost Facility,<br />
http://www.suffolkcoastal.gov.uk/yourdistrict/greenissues/greenprint/forum/parhamvisit/default.htm<br />
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Upcoming projects include <strong>the</strong> Mytum & Sel<strong>by</strong> site, which is constructing a 25,000 <strong>to</strong>nnes per annum<br />
facility, due <strong>to</strong> be operatational <strong>by</strong> Oc<strong>to</strong>ber 2009. Phase two would see this capacity increase <strong>to</strong> 75,000<br />
<strong>to</strong>nnes per annum. 274<br />
9.3 Hydrolysis and fermentation of lignocellulose<br />
(Biological 2nd Generation Biofuel)<br />
Wood<br />
waste,<br />
Agricultural<br />
/ cereal<br />
waste<br />
Pre<br />
treatment<br />
Hydrolysis/<br />
saccharification<br />
Fermentation<br />
Process Description<br />
Most ethanol is produced industrially <strong>by</strong> <strong>the</strong> fermentation of sugars <strong>by</strong> yeasts or bacteria although a small<br />
quantity is produced <strong>by</strong> <strong>the</strong> hydration of ethylene. The most common processes use simple sugars such<br />
as sucrose that <strong>the</strong> organisms can easily process. These sugars are found in food crops, ei<strong>the</strong>r directly<br />
as in sugar cane and beet, or as starch in grain that is converted <strong>to</strong> sugar <strong>by</strong> <strong>the</strong> action of an enzyme.<br />
Wood and <strong>the</strong> stem material of plants - lignocellulosic material - are also composed <strong>to</strong> a large extent of<br />
sugars and are much more abundant. However <strong>the</strong>se sugars are unsuitable for fermenting organisms<br />
and locked in<strong>to</strong> <strong>the</strong> plant structure.<br />
Lignocellulosic material contains two sugars, cellulose and hemi-cellulose, both in polymer form. They<br />
are enclosed <strong>by</strong> coating of lignin, a compound with no sugars that gives <strong>the</strong> plant its structural strength.<br />
To obtain fermentable sugars it is first necessary <strong>to</strong> release <strong>the</strong> cellulose and hemi-cellulose from <strong>the</strong><br />
lignin and <strong>the</strong>n hydrolyse <strong>the</strong>m <strong>to</strong> simple sugars. These can <strong>the</strong>n be fermented <strong>by</strong> yeasts, or more<br />
usually, bacteria <strong>to</strong> produce ethanol.<br />
The generic flowsheet for this process has four sequential steps covering a pre-treatment step <strong>to</strong> release<br />
lignin and hydrolyse <strong>the</strong> hemicellulose, hydrolysis of <strong>the</strong> cellulose <strong>to</strong> simple sugars, fermentation, and<br />
purification of <strong>the</strong> ethanol produced. Of <strong>the</strong>se steps pre-treatment and hydrolysis have proved technically<br />
<strong>the</strong> most difficult and <strong>the</strong> subject of most research and development.<br />
Pretreatment. The first operations are normally physical treatments <strong>to</strong> reduce <strong>the</strong> size and increase <strong>the</strong><br />
surface area of <strong>the</strong> feeds<strong>to</strong>ck that improve its accessibility <strong>to</strong> <strong>the</strong> reagents used. Washing may also be<br />
necessary for some feeds<strong>to</strong>cks, and steaming followed <strong>by</strong> solvent washing has been proposed <strong>to</strong> remove<br />
resins that may inhibit <strong>the</strong> later biological processes.<br />
Normally <strong>the</strong> breaking of <strong>the</strong> structure is achieved <strong>by</strong> a dilute acid that will break <strong>the</strong> lignin free from <strong>the</strong><br />
structure <strong>to</strong> liberate <strong>the</strong> sugars, and at <strong>the</strong> same time hydrolyse <strong>the</strong> hemi-cellulose polymer <strong>to</strong> simpler<br />
274 Mytum & Sel<strong>by</strong> plans £45m waste-<strong>to</strong>-biofuel plant, Letsrecycle.com 13 th March 2009.<br />
Purification<br />
Ethanol
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Xylose and 5 carbon sugars. Some cellulose will also be converted <strong>to</strong> 6 carbon sugars, but most will be<br />
hydrolysed in <strong>the</strong> following stage.<br />
Physical methods have also been proposed for pre-treatment, usually in combination with dilute acid<br />
treatment, <strong>the</strong> most common being steam explosion where <strong>the</strong> slurry in <strong>the</strong> pre-treatment stage is flashed<br />
<strong>to</strong> low pressure through a choke causing <strong>the</strong> cell structure <strong>to</strong> burst during decompression. The same<br />
explosive decompression effect has been demonstrated using ammonia and CO2 as <strong>the</strong> medium.<br />
A consequence of <strong>the</strong> acidic conditions is that some of <strong>the</strong> sugars will be converted <strong>to</strong> furfans and o<strong>the</strong>r<br />
compounds that may inhibit <strong>the</strong> fermentation organisms in a later stage. A key development challenge for<br />
process designers is <strong>to</strong> minimise <strong>the</strong> production of inhibi<strong>to</strong>rs whilst maximising <strong>the</strong> yield of simple sugars.<br />
Acid will need <strong>to</strong> be recovered and sugars washed from <strong>the</strong> process and <strong>the</strong> liquor neutralised following<br />
pre-treatment. Lignin is also removed at this stage. Most developers propose <strong>to</strong> use this as a fuel for<br />
power and process heat generation.<br />
Cellulose Hydrolysis. Pre-treatment is followed <strong>by</strong> a second hydrolysis stage where <strong>the</strong> cellulose is<br />
converted <strong>to</strong> 6 carbon sugars. His<strong>to</strong>rically this has been achieved <strong>by</strong> acid hydrolysis using a higher<br />
temperature but lower concentration acid than in <strong>the</strong> pre-treatment step. An alternative route is <strong>to</strong> use<br />
concentrated acids which improves <strong>the</strong> yield of sugar but is critically dependent for its economics on<br />
effective recovery and reuse of <strong>the</strong> acid. This is technically possible but difficult and involves complex<br />
engineering.<br />
Acid based processes have been proven for many years but only now are demonstrations being planned<br />
in <strong>the</strong> USA and <strong>the</strong> EU. This lack of progress has been his<strong>to</strong>rically due <strong>to</strong> <strong>the</strong> expensive equipment<br />
necessary and <strong>the</strong> low price of competing ethanol from sugar and grain. Only with <strong>the</strong> recent interest in<br />
ethanol as a biofuel has development restarted on this process.<br />
Following hydrolysis <strong>the</strong> process will include separation stages <strong>to</strong> wash out <strong>the</strong> sugars and remove<br />
fermentation inhibi<strong>to</strong>rs such as heavy metal contaminants and organic products of hydrolysis followed <strong>by</strong><br />
neutralisation with lime if acid has been used.<br />
In <strong>the</strong> last decade, an alternative, enzyme hydrolysis route has been proposed and developed <strong>to</strong> pilot<br />
stage. This technology has <strong>the</strong> potential <strong>to</strong> achieve high conversion rates with low production of inhibi<strong>to</strong>rs<br />
due <strong>to</strong> <strong>the</strong> mild reaction conditions. The key development necessary for commercialisation is <strong>to</strong> reduce<br />
<strong>the</strong> cost of <strong>the</strong> enzyme cellulase <strong>by</strong> an order of magnitude. Enzyme based processes are still in <strong>the</strong><br />
development phase but offer <strong>the</strong> prospect of being economically more attractive than o<strong>the</strong>r options if <strong>the</strong>ir<br />
fur<strong>the</strong>r development is successful. Demonstrations are planned in Canada, USA and EU.<br />
Fermentation.<br />
The sugars from ei<strong>the</strong>r hydrolysis route contain five and six carbon a<strong>to</strong>ms and need <strong>to</strong> be fermented in a<br />
microbial process ra<strong>the</strong>r than <strong>the</strong> yeast process used for simple sugars from sugar beet, sugar cane and<br />
grains. Typically <strong>the</strong>se are proprietary recombinant organisms whose metabolisms have been tailored <strong>to</strong><br />
<strong>the</strong> sugars in <strong>the</strong> process. We understand work is also being carried out on advanced yeasts.<br />
Development status<br />
A substantial research programme has been underway for over a decade in <strong>the</strong> USA and EU <strong>to</strong><br />
commercialise this technology. 275 This has resulted in several demonstration plants, but as yet no <strong>full</strong>y<br />
commercial installations. 276 Progress has been made however and <strong>the</strong> US have announced a target of<br />
producing ethanol from lignocellulose <strong>to</strong> <strong>the</strong> same price as that from corn <strong>by</strong> 2012.<br />
275 IEA (2008) From first <strong>to</strong> second generation biofuel technologies: An over view of current industry and R,D & D activities<br />
276 www.abc-energy.at/biotreibs<strong>to</strong>ffe/demoplants.php.<br />
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Current key <strong>to</strong>pics for research are <strong>the</strong> improvement of <strong>the</strong> organisms used in <strong>the</strong> process <strong>to</strong> improve<br />
yields and efficiency and <strong>the</strong> combination of several processes in <strong>the</strong> same unit operation <strong>to</strong> reduce<br />
capital costs.<br />
Current plans in <strong>the</strong> USA indicate that one of <strong>the</strong> most promising configurations for a demonstration will<br />
be <strong>to</strong> install <strong>the</strong> hydrolysis stages on a corn ethanol site <strong>to</strong> process <strong>the</strong> maize harvesting residue.<br />
Scale of operation – Regional<br />
The reliance on clean feeds<strong>to</strong>ck would suggest that this would be a regional technology drawing from<br />
agricultural residues such as straw and chipped wood fuels. The low bulk densities would tend <strong>to</strong> reduce<br />
<strong>the</strong> economic transport radius. However <strong>the</strong> process involves complex process engineering which<br />
responds well <strong>to</strong> <strong>the</strong> economies of scale.<br />
Hydrolysis feed s<strong>to</strong>cks<br />
Feed s<strong>to</strong>cks for hydrolysis based processes need <strong>to</strong> be clean waste, virgin wood or agricultural residues.<br />
The microbial fermentation is susceptible <strong>to</strong> poisoning if contaminated waste biomass is used as a<br />
feeds<strong>to</strong>ck.<br />
Table 72 The suitability of feeds<strong>to</strong>cks for hydrolysis processes<br />
SRF<br />
Waste<br />
Wood<br />
Clean<br />
Wood<br />
Domestic<br />
Pellet<br />
Industrial<br />
Pellet<br />
Unsorted<br />
Waste<br />
Wet<br />
Wastes<br />
Agricultural<br />
Residues<br />
<br />
T C Fuels – Thermochemical Fuels<br />
A contrary view on <strong>the</strong> necessity for clean feeds<strong>to</strong>cks is taken <strong>by</strong> Aquegen who propose using MSW<br />
fractions at <strong>the</strong>ir installation <strong>to</strong> be built in <strong>the</strong> UK at South Milford in West Yorkshire. The chemical<br />
process appears <strong>to</strong> be acid hydrolysis of <strong>the</strong> cellulose and hemi cellulose but <strong>the</strong> impact on <strong>the</strong><br />
fermentation stage is unclear and operating data is scarce.<br />
UK Biomass <strong>to</strong> Ethanol Plant<br />
Mytum and Sel<strong>by</strong> have planning permission for <strong>the</strong> creation of a biomass <strong>to</strong> ethanol facility at South<br />
Milford in West Yorkshire, as a joint venture with AqueGen. The intended site will be capable of<br />
processing 400,000 <strong>to</strong>nnes of waste food, ABP (Animal By Product) and liquids in<strong>to</strong> 100 million litres of<br />
alcohol each year. It is hoped that <strong>the</strong> site will be operational <strong>by</strong> 2011. 274<br />
Table 73 Risks Associated with Ethanol from lignocellulose waste<br />
Level of Risk Comment<br />
Technical High The technology remains innovative with only small<br />
demonstration and pilot projects built so far.<br />
Feeds<strong>to</strong>cks are currently limited <strong>to</strong> clean wood and<br />
agricultural residues. Contamination from o<strong>the</strong>r<br />
sources could damage <strong>the</strong> fermentation process.<br />
Social & Planning Medium Process should be no more difficult <strong>to</strong> implement<br />
than a biomass power plant.<br />
Implementation is likely <strong>to</strong> be on an existing grain<br />
ethanol site<br />
Financial High The combination of expensive processing and <strong>the</strong><br />
need for good quality feeds<strong>to</strong>ck means that<br />
product will be more expensive than imported<br />
ethanol for some time. Plant economics will be<br />
sensitive <strong>to</strong> price competition for feeds<strong>to</strong>ck and<br />
competition from improved cane sugar ethanol<br />
processes for final product. This may make it<br />
T C<br />
Fuels
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Level of Risk Comment<br />
unsuitable for use in <strong>the</strong> UK.<br />
Regula<strong>to</strong>ry Medium Would require additional subsidy from Renewable<br />
transport fuels obligation.<br />
9.4 Conclusions for Biological Processes<br />
Biological processes for waste include anaerobic digestion for <strong>the</strong> production of methane fuel gas and <strong>the</strong><br />
hydrolysis and subsequent fermentation <strong>to</strong> ethanol fuels of <strong>the</strong> hemi-cellulose and cellulose fractions of<br />
lignocellulosic materials.<br />
Following our review of <strong>the</strong>se technologies our conclusions are as follows;<br />
• Anaerobic digestion processes are technically viable and available for most wet waste feeds<strong>to</strong>cks<br />
including sewage bio-solids.<br />
• There is much discussion concerning whe<strong>the</strong>r AD is economically viable for standard fee waste at<br />
<strong>the</strong> moment. Greater interest in applying this disposal method is being stimulated <strong>by</strong> <strong>the</strong> revised<br />
Waste Framework Directive, and interest in biogas for transport.<br />
• Using a proportion of food waste is important <strong>to</strong> <strong>the</strong> economics of anaerobic digestion due <strong>to</strong> its<br />
high gas generation potential and gate fee. Manures are bulky and have poor gas potential.<br />
• Digestate disposal is becoming difficult due <strong>to</strong> constraints in nitrogen sensitive areas.<br />
• Composting is a lower cost alternative <strong>to</strong> AD but does not produce energy and can be regarded<br />
as a competi<strong>to</strong>r <strong>to</strong> AD. It is popular with waste managers due <strong>to</strong> <strong>the</strong> cost and its status as a<br />
recovery, ra<strong>the</strong>r than a disposal process. Disposal of compost <strong>to</strong> land suffers from <strong>the</strong> same<br />
constraints as AD digestates.<br />
• Hydrolysis and subsequent fermentation <strong>to</strong> ethanol fuels of <strong>the</strong> hemicellulose and cellulose<br />
fractions of lignocellulosic materals is still at <strong>the</strong> development stage although <strong>the</strong>re are plans for<br />
demonstrations in <strong>the</strong> EU and USA.<br />
• Feeds<strong>to</strong>cks are limited at present <strong>to</strong> clean wood and agricultural residues.<br />
o We question whe<strong>the</strong>r hydrolysis and fermentation should be a priority for <strong>the</strong> UK at<br />
present where clean residues are relatively expensive and could potentially be used in<br />
more efficient ways.<br />
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10 Thermochemical processes for generating<br />
energy<br />
Thermochemical processes for <strong>the</strong> generation of energy are taken as gasification and pyrolysis in <strong>the</strong><br />
Chapter. Combustion, gasification and pyrolysis all use heat <strong>to</strong> break down <strong>the</strong> structure of <strong>the</strong> feeds<strong>to</strong>ck<br />
so that <strong>the</strong> chemical energy can be released ei<strong>the</strong>r as heat or a fuel product. The conditions in <strong>the</strong><br />
reac<strong>to</strong>r determine <strong>the</strong> products.<br />
When combustible waste enters a high temperature environment it will first dry and <strong>the</strong>n decompose in<strong>to</strong><br />
volatile gas and char components.<br />
A combustion process is always supplied with an excess of air so <strong>the</strong> char and volatile gas burn<br />
completely. The energy in <strong>the</strong> waste is released within <strong>the</strong> combustion equipment and <strong>the</strong> flue gas<br />
from it. It is recovered as hot water or steam.<br />
Gasification processes use a limited supply of oxidant; usually air, <strong>to</strong> maintain both combustion and<br />
reducing reactions in <strong>the</strong> same reac<strong>to</strong>r. These reactions produce carbon monoxide (CO), hydrogen<br />
(H2) and hydrocarbons as well as combustion products. Most of <strong>the</strong> energy in <strong>the</strong> fuel is transferred<br />
in<strong>to</strong> <strong>the</strong> calorific value (CV) of <strong>the</strong> gas leaving <strong>the</strong> reac<strong>to</strong>r. This gas can be burned separately in a<br />
boiler, engine or gas turbine. Alternatively it can be converted <strong>by</strong> a syn<strong>the</strong>sis reaction <strong>to</strong> methane for<br />
injection <strong>to</strong> <strong>the</strong> Natural Gas Grid or liquid fuels for transport.<br />
In a pyrolysis process <strong>the</strong>re is no oxygen and <strong>the</strong> char and volatile gas remain largely unchanged.<br />
The energy in <strong>the</strong> waste is retained in <strong>the</strong> CV of <strong>the</strong> gas and char removed from <strong>the</strong> reac<strong>to</strong>r. These<br />
can <strong>the</strong>n be burned separately in a boiler, engine or gas turbine. Some pyrolysis processes produce<br />
gases that can be condensed in<strong>to</strong> a liquid fuel. Pyrolysis products can also be fur<strong>the</strong>r upgraded <strong>to</strong><br />
transport fuels although <strong>the</strong> technologies required are not yet commercially available.<br />
There are a number of advantages of converting solid waste in<strong>to</strong> a gas or liquid fuel.<br />
• Cleaning a small fuel gas stream before combustion ra<strong>the</strong>r than a large flue gas flow as in an<br />
incinera<strong>to</strong>r reduces <strong>the</strong> size of <strong>the</strong> pollution control equipment.<br />
• The controlled combustion in a gas flame, as opposed <strong>to</strong> a grate, may also reduce <strong>the</strong> extent and<br />
complexity of final gas cleaning.<br />
• The two points above make installations economically possible that are smaller than current<br />
incinera<strong>to</strong>rs. These should be more acceptable for permitting and more compatible with <strong>the</strong><br />
throughputs of <strong>the</strong> newer mechanical separation and o<strong>the</strong>r recycling and recovery processes.<br />
• Higher electrical output per <strong>to</strong>nne is possible if high-pressure boilers, gas turbines or engines are<br />
used.<br />
• Alternative energy products such as methane and liquid fuels can be manufactured <strong>by</strong> chemical<br />
syn<strong>the</strong>sis using <strong>the</strong> products of gasification or pyrolysis as a base.<br />
In <strong>the</strong> sections below we discuss how <strong>the</strong>rmal technologies are used <strong>to</strong> generate energy from waste,<br />
what demands <strong>the</strong>y make of <strong>the</strong> feeds<strong>to</strong>ck, <strong>the</strong>ir commercial status and <strong>the</strong> risks of deployment.<br />
These advantages are often quoted <strong>by</strong> gasification and pyrolysis suppliers as solutions for perceived<br />
weaknesses in <strong>the</strong> current market leader – combustion with energy recovery. These claims are shown in<br />
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Table 74 Claims for gasification/pyrolysis with comments<br />
Incineration Gasification/pyrolysis Comment<br />
Large (Regional) size and<br />
fuel demand suppresses<br />
recycling.<br />
Small volume of Hazardous<br />
and <strong>to</strong>xic fly ash.<br />
Bulky residual ash can be<br />
used as a aggregate.<br />
Poor electrical efficiency<br />
and lack of suitable heat<br />
loads gives poor resource<br />
use efficiency.<br />
Can be built economically at<br />
<strong>the</strong> smaller sizes that can be<br />
integrated in<strong>to</strong> local<br />
schemes.<br />
This remains <strong>to</strong> be<br />
demonstrated, but is<br />
probably true.<br />
No dioxin found in fly ash. This seems <strong>to</strong> be valid.<br />
Some options give low<br />
volume compact ash.<br />
Some options can give very<br />
high electrical efficiencies.<br />
Smaller sizes can match heat<br />
loads better. Particularly as<br />
<strong>the</strong>se are often independent<br />
of <strong>the</strong> power supply.<br />
Electricity and or heat only Some options can be used <strong>to</strong><br />
generate gas or transport<br />
fuels<br />
10.1 Gasification<br />
RDF<br />
Waste wood<br />
Clean wood<br />
Ag residues<br />
Gasification<br />
Syn gas<br />
Valid. Some incinera<strong>to</strong>rs can<br />
give low volume slag like ash<br />
but at a very high energy cost<br />
for ash melting.<br />
Very few demonstrations of<br />
high electrical efficiency.<br />
Lack of enthusiasm for CHP.<br />
Installations in wood waste<br />
sec<strong>to</strong>r now making progress.<br />
True at very large scale.<br />
Process Description<br />
In simple terms gasification is <strong>the</strong> conversion of a solid fuel <strong>to</strong> a gas that has sufficient energy value <strong>to</strong> be<br />
useful as a fuel or feeds<strong>to</strong>ck in its own right.<br />
This concept is refined in <strong>the</strong> definition for <strong>the</strong> Renewables Obligation <strong>to</strong> <strong>the</strong> subs<strong>to</strong>ichiometric oxidation<br />
or steam reformation of a substance <strong>to</strong> produce a gaseous mixture containing two or all of <strong>the</strong> following:<br />
oxides of carbon, methane and hydrogen and which has a gross calorific value of at least 4.0 MJ/m 3 when<br />
sampled at <strong>the</strong> inlet <strong>to</strong> <strong>the</strong> genera<strong>to</strong>r and measured at 0.1 MPa and 25°C. 277<br />
277 Renewables Obligation: Defining <strong>the</strong> different types of electricity generation using biomass and waste www.berr.gov.uk<br />
Methanation<br />
Grid Injected<br />
SNG<br />
Fischer<br />
Tropsch<br />
CHP<br />
2 nd gen<br />
biofuels<br />
Heat,<br />
Power<br />
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Gasification has been success<strong>full</strong>y used with coal, in <strong>the</strong> American Great Plains project <strong>to</strong> generate<br />
syn<strong>the</strong>tic natural gas and in South Africa <strong>to</strong> generate transport fuels. There are also instances<br />
internationally where gasification has been used with SRF waste as a feeds<strong>to</strong>ck.<br />
A gasification for energy process has four steps, <strong>the</strong> gasifier itself that produces <strong>the</strong> gas, feeds<strong>to</strong>ck<br />
preparation <strong>to</strong> get <strong>the</strong> fuel in <strong>the</strong> right form for <strong>the</strong> gasifier, <strong>the</strong> clean-up of <strong>the</strong> gas, and <strong>the</strong> utilisation of<br />
<strong>the</strong> clean gas for energy. This is shown Figure 19.<br />
Step<br />
Material<br />
state<br />
Typical<br />
equipment<br />
and<br />
process<br />
Step 1<br />
Pretreatment<br />
Step 2<br />
Thermal<br />
reac<strong>to</strong>r<br />
Step 3<br />
Gas<br />
conditioning<br />
Solid Waste Raw gas<br />
Clean Gas<br />
Separation<br />
of glass and<br />
metals.<br />
Screening<br />
Shredding<br />
Pelleting or<br />
briquetting<br />
Fluidised<br />
bed reac<strong>to</strong>rs<br />
Externally<br />
heated<br />
reac<strong>to</strong>rs<br />
Fixed bed<br />
reac<strong>to</strong>rs<br />
Entrained<br />
flow<br />
reac<strong>to</strong>rs<br />
Gas<br />
coolers<br />
Filters<br />
Liquid<br />
scrubbers<br />
Figure 19 Steps in a gasification process<br />
Step 4<br />
Conversion<br />
<strong>to</strong> energy<br />
Energy<br />
products<br />
Steam<br />
boilers<br />
Engines<br />
Gas<br />
turbines<br />
Chemical<br />
syn<strong>the</strong>sis<br />
The gasification process<br />
The gasification reactions that produce <strong>the</strong> fuel gas components are endo<strong>the</strong>rmic and need a constant<br />
supply of heat <strong>to</strong> sustain production. This heat is supplied <strong>by</strong> <strong>the</strong> combustion of part of <strong>the</strong> fuel. The<br />
challenge is for <strong>the</strong> equipment design <strong>to</strong> transfer heat from exo<strong>the</strong>rmic combustion <strong>to</strong> endo<strong>the</strong>rmic<br />
gasification. There are two main types although <strong>the</strong>re are many variants in each category.<br />
Direct – This process occurs in a single reac<strong>to</strong>r where oxygen or air and usually superheated steam is<br />
supplied <strong>to</strong> <strong>the</strong> same vessel so that some combustion occurs in situ providing <strong>the</strong> required heat <strong>to</strong> drive<br />
<strong>the</strong> gasification reactions. The direct use of air dilutes <strong>the</strong> product gas and results in a low calorific value<br />
fuel commonly referred <strong>to</strong> as producer gas.<br />
Indirect – Here gasification and combustion process occur in separate fluid bed reac<strong>to</strong>rs. Heat is usually<br />
transferred <strong>by</strong> circulating <strong>the</strong> fluidised bed material between <strong>the</strong> two beds. This concept is more complex<br />
than <strong>the</strong> direct process but produces a gas with a higher calorific value.
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Table 75 Gas compositions of typical gasifier types<br />
Compound Typical indirect<br />
(Gussing twin<br />
fluid bed)<br />
% <strong>by</strong> volume<br />
Typical Direct<br />
(Downdraft fixed<br />
bed)<br />
% <strong>by</strong> volume<br />
Direct bubbling<br />
fluid bed<br />
% <strong>by</strong> volume<br />
Carbon monoxide 22.7 % 21.4 %v 11-15 %v<br />
Hydrogen 31.5 %v 15.38 %v 8-13 %v<br />
Methane 11.2 %v 2.05 %v 5-8 %v<br />
Higher hydrocarbons 4.0 %v 0.5-1.5 %v<br />
Carbon dioxide 27.4 %v 11.82 %v 14-16 %v<br />
Nitrogen & Oxygen 2.8% 49.35% 35-45 %v<br />
Water vapour As dry As dry 14-21 %v<br />
LHV, kJ/Nm 3<br />
12,000 - 13,000 5,005 –5,200-5,800<br />
There are a wide variety of commercial processes on <strong>the</strong> market. The list below gives <strong>the</strong> basic generic<br />
types.<br />
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Table 76 Generic gasifier types<br />
Type Description Direct/<br />
indirect<br />
Fixed bed Fuel, air and <strong>the</strong> produced gas flow co currently direct<br />
downdraft downwards through a reac<strong>to</strong>r with a converging<br />
base section.<br />
Fixed bed updraft Fuel and air flow counter currently through a<br />
cylindrical bed.<br />
direct<br />
Fluidised bed The waste is gasified in a hot bed of sand or direct<br />
direct<br />
limes<strong>to</strong>ne that is agitated <strong>by</strong> air and <strong>the</strong> gas product.<br />
This is known as a fluidised bed. Char burns in situ<br />
<strong>to</strong> provide heat. The fluidised bed can be retained<br />
within <strong>the</strong> reac<strong>to</strong>r vessel as a coherent bed with only<br />
gas and dust leaving or <strong>the</strong> velocity of <strong>the</strong> gas can<br />
be increased <strong>to</strong> <strong>the</strong> point that bed material is<br />
transported from <strong>the</strong> <strong>to</strong>p of <strong>the</strong> vessel necessitating<br />
its recirculation back <strong>to</strong> <strong>the</strong> reac<strong>to</strong>r. These two<br />
patterns are respectively referred <strong>to</strong> as bubbling<br />
and circulating fluidised beds.<br />
Fluidised bed The waste is gasified in a turbulent bed of sand or indirect<br />
indirect<br />
limes<strong>to</strong>ne. Char from <strong>the</strong> reaction is transferred with<br />
sand <strong>to</strong> a separate vessel where it is burned in air.<br />
Heat is transferred <strong>by</strong> sand circulation. As with <strong>the</strong><br />
direct type <strong>the</strong> fluidised beds can be bubbling or<br />
circulating.<br />
Heated kilns The waste is tumbled in a rotating drum heated <strong>by</strong><br />
<strong>the</strong> combustion of some of <strong>the</strong> product gas<br />
indirect<br />
Small heated tubes The waste is progressed <strong>by</strong> a screw or ram through<br />
a tube heated <strong>by</strong> <strong>the</strong> combustion of some of <strong>the</strong><br />
product gas.<br />
indirect<br />
Large heated tubes The waste is progressed <strong>by</strong> a screw or ram through<br />
a tube heated <strong>by</strong> <strong>the</strong> combustion of some of <strong>the</strong><br />
product gas.<br />
Indirect<br />
Large entrained Finely divided or liquid fuel is gasified as a flame direct<br />
flow<br />
with oxygen.<br />
Plasma gasification High temperature plasma from an electric arc<br />
dissociates <strong>the</strong> waste in<strong>to</strong> its component molecules<br />
Direct<br />
Feeds<strong>to</strong>cks<br />
The feeds<strong>to</strong>ck quality requirements depend on <strong>the</strong> size and <strong>the</strong> design of <strong>the</strong> gasification process. While<br />
most <strong>the</strong>rmal gasification processes work best with dry regularly sized feeds<strong>to</strong>cks <strong>the</strong>re are some limited<br />
examples of processes that will accept unsorted MSW. In general, <strong>the</strong> smaller <strong>the</strong> gasification unit, <strong>the</strong><br />
more stringent <strong>the</strong> quality requirements will be for <strong>the</strong> feeds<strong>to</strong>ck being used. The requirements for each<br />
of <strong>the</strong> types identified above are summarised below.
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Table 77 Gasifier feeds<strong>to</strong>ck requirements<br />
Gasifier<br />
Type<br />
Fixed bed<br />
downdraft<br />
Typical<br />
Size MW<br />
fuel<br />
1 MW<br />
modules<br />
Fixed bed 10 MW<br />
updraft modules<br />
Fluidised 25MW<br />
bed direct or upwards<br />
indirect<br />
Heated kilns 20MW<br />
modules<br />
Small<br />
heated<br />
tubes<br />
Large<br />
heated<br />
tubes<br />
Large<br />
entrained<br />
flow<br />
10 MW<br />
modules<br />
Fuel Quality<br />
Regularly<br />
sized, dry and<br />
clean wood<br />
chips with low<br />
ash. Possibly<br />
pellets<br />
Wood chip<br />
SRF<br />
Waste Wood<br />
Clean Wood<br />
<br />
most qualities <br />
Most dry<br />
shredded<br />
materials<br />
Most shredded<br />
materials not<br />
necessarily dry<br />
Most dry<br />
shredded<br />
materials not<br />
necessarily dry<br />
50MW Minimally<br />
sorted or<br />
prepared<br />
100 MW<br />
upwards<br />
Plasma 2MW<br />
upwards<br />
T C Fuels – Thermochemical Fuels<br />
materials<br />
Capable of<br />
high pressure<br />
pneumatic<br />
transport or<br />
slurry<br />
component<br />
Most shredded<br />
materials not<br />
necessarily dry<br />
Domestic Pellet<br />
Industrial Pellet<br />
Unsorted Waste<br />
Wet Wastes<br />
Agricultural<br />
Residues<br />
T C Fuels<br />
<br />
<br />
<br />
<br />
<br />
<br />
With <strong>the</strong> exception of <strong>the</strong> direct fluidised beds none of <strong>the</strong> gasification processes above can be<br />
considered <strong>to</strong> be widely available commercially. The allocation of feeds<strong>to</strong>ck is <strong>the</strong>refore an estimate<br />
based on AEA knowledge.<br />
Primary Gas Cleaning<br />
The gas from <strong>the</strong> gasifier contains a range of contaminants. The most important are dust and residual<br />
organic compounds or tars that can cause difficulties for <strong>the</strong> following conversion process. The extent of<br />
cleaning necessary varies with <strong>the</strong> end use of <strong>the</strong> gas, so a fluidised bed gasifier supplying hot gas <strong>to</strong> a<br />
coal fired utility boiler will have minimal dust removal whereas a unit supplying gas <strong>to</strong> a reciprocating<br />
engine will need reliable dust, tar and acid gas removal. Syn<strong>the</strong>sis processes require a very high level of<br />
purity <strong>to</strong> avoid poisoning of <strong>the</strong> catalysts used in <strong>the</strong> reactions - <strong>the</strong>se are more properly regarded as part<br />
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of <strong>the</strong> syn<strong>the</strong>sis package and so will be described below in that section. The requirements for <strong>the</strong> more<br />
demanding end uses have been summarised <strong>by</strong> <strong>the</strong> Karlsruhe Institute of Technology. 278 .<br />
Cleaning processes, especially those for <strong>the</strong> tars, have proved exceptionally difficult <strong>to</strong> design and<br />
implement in practice and are <strong>the</strong> principal cause of project failure where engines and gas turbines are<br />
used.<br />
Options that have shown success are:<br />
For tar removal<br />
• Catalytic cracking or steam reforming on limes<strong>to</strong>ne or nickel catalysts. (VTT, Condens)<br />
• Filtration on ceramic filter with limes<strong>to</strong>ne precoat. (Gussing, Biomass Engineering)<br />
• Liquid scrubbing with vegetable oil or biodiesel. (Gussing, Xylowatt)<br />
• Wet electrostatic precipita<strong>to</strong>rs (REFgas)<br />
• Plasma reaction chamber. (Europlasma)<br />
For dust removal<br />
• Ceramic, or sintered metal filters (Guessing, Biomass Engineering)<br />
• Cyclones<br />
• Liquid scrubbers with vegetable oil or biodiesel. (Gussing, Xylowatt)<br />
• Plasma reaction chamber. (Europlasma)<br />
Table 78 Syngas trace contaminants and target levels in ppm 278<br />
mg/Nm 3 Biomass<br />
gasification<br />
Gas mo<strong>to</strong>r Gas turbine MeOH FT (Sasol)<br />
Particles 10 4 – 10 5 < 50 < 1 0.2 n.s.<br />
Tar 0 – 20,000 < 100 < 5 < 1 n.s.<br />
Alkali 0.5 – 5 n.s. < 0.2 < 0.2 < 0.01<br />
NH3, HCN 200 – 2000 < 55 n.s. < 0.1 < 0.02<br />
H2S, COS 50 – 100 < 1150 < 1 < 0.1 < 0.01<br />
Halogens 0 – 300 n.s. < 1 < 0.1 < 0.01<br />
Heavy<br />
Metals<br />
0.005 - 10 n.s. n.s. n.s. < 0.001<br />
n.s = not specified<br />
Gas conversion<br />
The clean gas has many uses. It can be burned directly, <strong>to</strong> provide heat, raise steam, or drive electrical<br />
genera<strong>to</strong>rs. It can also be used as a feeds<strong>to</strong>ck for fur<strong>the</strong>r processes <strong>to</strong> syn<strong>the</strong>sise methane, diesel fuel<br />
components and o<strong>the</strong>r chemicals and fuels.<br />
Without doubt <strong>the</strong> most successful application <strong>to</strong> date has been <strong>the</strong> direct combustion of gas in industrial<br />
processes and boilers.<br />
The most quoted example of process use is <strong>the</strong> use of fluidised bed gasifiers producing low calorific gas<br />
for heating lime kilns in <strong>the</strong> paper and pulp industry. Typically <strong>the</strong> gas is burned through a burner nozzle<br />
designed for <strong>the</strong> low calorific value directly in<strong>to</strong> <strong>the</strong> combustion chamber of <strong>the</strong> process unit. One unit in<br />
Varo Sweden has been operating since 1987. 279<br />
Gas can also be used <strong>to</strong> raise steam in a boiler which can in turn be used for power generation. This is a<br />
robust concept that carries much less technical risk than <strong>the</strong> use of engines or gas turbines. Prime<br />
examples of this are those processes based on an externally heated reac<strong>to</strong>r with all <strong>the</strong> heat release in a<br />
278 IEA Bioenergy Agreement Task 33 Spring 2009 Workshop, Karlsruhe, www.gastechnology.org/iea German country update<br />
279 IEA Bioenergy Agreement Task 33 Spring 2009 Workshop, Karlsruhe, www.gastechnology.org/iea Swedish country update.
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high temperature combustion chamber followed <strong>by</strong> a boiler (Ethos Energy, Thermoselect, Mitsui MES<br />
R21). These have all proved reliable in commercial service and delivered substantial emissions benefits.<br />
A special case of this is <strong>the</strong> use of gas for firing district heating plant. Through <strong>the</strong> 1980’s a Finnish<br />
company, Bioneer, installed a series of updraft gasifiers linked directly <strong>to</strong> hot water heating boilers in<br />
Finland and Sweden. These were very successful and reliable but development s<strong>to</strong>pped after <strong>the</strong><br />
company was sold <strong>to</strong> a major engineering concern.<br />
There are plans <strong>to</strong> implement a project in east London (ELSEF) that will use a fluidised bed gasifier,<br />
fuelled <strong>by</strong> SRF from a neighbouring waste management facility. Here <strong>the</strong> gas would be cleaned of acid<br />
gas components which allows <strong>the</strong> use a much higher pressure boiler and turbine than would be possible<br />
with a combustion plant and hence potential for higher electrical efficiency in power and CHP cycles.<br />
A fur<strong>the</strong>r related application that is enjoying considerable success is <strong>the</strong> use of a circulating fluidised bed<br />
gasifier close-coupled <strong>to</strong> a coal fired boiler. Three installations have been built: Lahti in Finland, Amer in<br />
Ne<strong>the</strong>rlands and Electrobel Ruien in Belgium. These units take a wide range of feeds<strong>to</strong>cks from SRF <strong>to</strong><br />
waste woods and plastics. The first installation of this type, Lahti in Finland was commissioned in 1998<br />
and has operated reliably since. Details of all of <strong>the</strong>se installations can be found on <strong>the</strong> IEA Bioenergy<br />
Agreement Task 32 database of cofiring installations 280 . The inherent simplicity of this approach and it’s<br />
ability <strong>to</strong> make use of <strong>the</strong> high efficiency steam cycle of <strong>the</strong> fossil fuel plant is attractive and fur<strong>the</strong>r<br />
installations are planned in Finland and Sweden. 279<br />
A class of installations that is enjoying some success in <strong>the</strong> UK is <strong>the</strong> close coupled gasifier and boiler,<br />
where waste is burned directly after production. This does not allow for acid gas removal but ensures<br />
that <strong>the</strong> gas is burned in a well developed and controlled flame that reduces o<strong>the</strong>r emissions <strong>to</strong> a low<br />
level. One of <strong>the</strong> most developed version is <strong>the</strong> Energos gasifier which is demonstrating a unit on <strong>the</strong> Isle<br />
of Wight as part of <strong>the</strong> Defra WIP. 281 Fur<strong>the</strong>r replications are planned in <strong>the</strong> UK. The controlled nature of<br />
<strong>the</strong> gasification and combustion reactions mean that this type of unit can be designed <strong>to</strong> burn sorted<br />
MSW and SRF in smaller heat and CHP installations than grate and fluidised bed combus<strong>to</strong>rs which<br />
means <strong>the</strong>y can be used <strong>to</strong> power industrial heat and high load chp installations that have high GHG<br />
abatement potential. A fur<strong>the</strong>r example of this type of technology is <strong>the</strong> Bioflame unit which is currently<br />
being marketed <strong>to</strong> produce CHP using waste wood chip as a fuel. 282<br />
Using <strong>the</strong> gas <strong>to</strong> generate electricity from combustion in a reciprocating engine or gas turbine has proved<br />
problematical and <strong>the</strong>re are very few examples of a <strong>full</strong>y commercial, reliable system operating <strong>to</strong>day.<br />
The obstacle is cleaning <strong>the</strong> gas of <strong>the</strong> tar and dust contamination that can damage <strong>the</strong> engine. This<br />
apparently simple task has defeated many engineers over several decades. There has however been<br />
some progress over <strong>the</strong> last five years;<br />
• At Gussing in Austria an indirect gasifier has been operating for over 20k hours fuelling a 2.5<br />
MWe reciprocating engine. The key <strong>to</strong> success here appears <strong>to</strong> be <strong>the</strong> combination of a ceramic<br />
filter with a liquid scrubber containing biodiesel.<br />
• Biomass Engineering Ltd in <strong>the</strong> UK have installed three downdraft/ engine systems in Germany<br />
that are generating reliably as CHP units supplying district heating. The key here seems <strong>to</strong> be<br />
close control over <strong>the</strong> feeds<strong>to</strong>ck sizing and quality combined with <strong>the</strong> use of a ceramic filter.<br />
• At Harboore in Denmark a fixed bed gasifier supplies three reciprocating engines in a local district<br />
heating system. Tar cleaned from <strong>the</strong> fuel gas is s<strong>to</strong>red and subsequently fired in a boiler <strong>to</strong> even<br />
out peaks in heating demand.<br />
280 http://www.ieabcc.nl/database/cofiring.php<br />
281 Lets recycle Tuesday 18 September 2007.<br />
282 http://www.bioflame.co.uk/<br />
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10.1.1 Using <strong>the</strong> gas <strong>to</strong> syn<strong>the</strong>sise fur<strong>the</strong>r products.<br />
As noted above <strong>the</strong> gas produced <strong>by</strong> gasifiers can be used <strong>to</strong> manufacture methane or transport fuels. A<br />
review of gasifier technologies, with a focus on those suitable for liquid fuel production from syngas, has<br />
been recently released <strong>by</strong> NNFCC. 283 Nitrogen dilution is not acceptable in this type of application and<br />
this route is restricted <strong>to</strong> direct gasifiers using oxygen as an oxidant and indirect gasifiers.<br />
Transport fuels produced <strong>by</strong> Fischer Tropsch syn<strong>the</strong>sis reactions are endo<strong>the</strong>rmic using syn-gas<br />
(syn<strong>the</strong>tic gas) <strong>to</strong> produce long chain hydrocarbons that can be distilled <strong>to</strong> produce transport fuels or<br />
intermediates for chemical processing. These reactions commonly require carbon monoxide, carbon<br />
dioxide and hydrogen in specific proportions. These proportions are adjusted <strong>by</strong> use of <strong>the</strong> shift reaction.<br />
The resulting gases are <strong>the</strong>n catalysed at temperatures of 150°C – 300°C, and elevated pressures <strong>by</strong> an<br />
iron or cobalt catalyst.<br />
CO + H2O ↔ CO2 + H2<br />
Shift Reaction<br />
(2n+1)H2 + nCO ↔ CnH(2n+2) + nH2O<br />
Fischer-Tropsch Reaction<br />
Methanation is an exo<strong>the</strong>rmic process that uses syn gas <strong>to</strong> produce methane that can be injected in<strong>to</strong> <strong>the</strong><br />
gas grid. Syn gas is catalytically reacted with steam at temperatures between 340°C – 550°C and up <strong>to</strong><br />
60 bar.<br />
CO + 3H2 ↔ CH4 + H2O<br />
A fur<strong>the</strong>r variation is <strong>the</strong> syn<strong>the</strong>sis of methanol which in turn can be converted <strong>to</strong> a range of organic<br />
chemicals and dimethyl e<strong>the</strong>r, potentially a fuel used in diesel engines. Nickel is commonly used as <strong>the</strong><br />
catalyst. These reactions commonly require carbon monoxide, carbon dioxide and steam in tightly<br />
controlled proportions which are obtained <strong>by</strong> <strong>the</strong> shift reaction and carbon dioxide absorption. Carbon<br />
dioxide removal is done <strong>by</strong> amine solvent scrubbing or refrigerated methanol scrubbing, both commercial<br />
refinery and gasworks processes. The use of catalysts requires a high level of purity from trace<br />
contamination, particularly sulphur and metals that must be removed <strong>to</strong> single ppm levels. This is usually<br />
done <strong>by</strong> passing over beds of zinc and copper oxide.<br />
The methanation reaction is highly exo<strong>the</strong>rmic and rejects heat at <strong>the</strong> reaction temperature of over 340°C.<br />
This makes it a useful source of process steam and in <strong>the</strong> past commercialisation of this technology has<br />
often been driven <strong>by</strong> <strong>the</strong> desire <strong>to</strong> use this <strong>to</strong> <strong>the</strong> <strong>full</strong>. A process producing 700MW of methane could<br />
produce 200MW of steam.<br />
Neste Oil, S<strong>to</strong>ra Enso, VTT and Forest Wheeler are exploring ways <strong>to</strong> transform wood waste in <strong>to</strong><br />
transport fuels through a Fischer-Tropsch process <strong>to</strong> give a usable syn-gas at a demonstration plant in<br />
Varkaus, Finland. 284 The plant is due <strong>to</strong> open in Spring of 2009, and will use forest residues such as<br />
branches, stumps and trimmings <strong>to</strong> generate heat and electricity for <strong>the</strong> attached papermill, and quantities<br />
of biowax, <strong>the</strong> raw material <strong>to</strong> be refined in<strong>to</strong> transport fuels and its use is <strong>to</strong> replace food oils. The facility<br />
is expected <strong>to</strong> have a capacity of around 100,000 <strong>to</strong>nnes p.a. of biowax.<br />
283 Review of Technologies for Gasification of Biomass and Wastes, NNFCC and E4Tech, June 2009.<br />
284 Transforming wood waste in<strong>to</strong> renewable fuel, http://www.nesteoil.com/default.asp?path=1,41,540,10793,10795,11601
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Table 79 Scales of operation<br />
Direct Downdraft <strong>to</strong><br />
CHP<br />
Local Regional National<br />
Updraft <strong>to</strong> CHP<br />
Fluid bed <strong>to</strong><br />
CHP and power<br />
only<br />
Updraft <strong>to</strong> CHP<br />
Indirect Fluid bed <strong>to</strong><br />
CHP<br />
Indirectly heated<br />
tubes and kilns<br />
for CHP and<br />
power only<br />
Oxygen blown<br />
entrained flow <strong>to</strong><br />
methane and 2 nd<br />
Gen Biofuels<br />
Fluid bed <strong>to</strong><br />
methane<br />
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Table 80 Risks and barriers associated with Gasification<br />
Local Scale<br />
Level of<br />
Risk<br />
Comment<br />
Technical High Very few operating commercial plant for power<br />
or CHP.<br />
Significant residual risk in gas cleaning for<br />
power production.<br />
Social & Planning Medium Likely <strong>to</strong> be located on an industrial site where<br />
impacts can be minimised.<br />
Financial High Poor track record of gasification technologies<br />
Regula<strong>to</strong>ry Medium Receives subsidy via <strong>the</strong> Renewables<br />
Obligation.<br />
Status of ash product is unclear under Waste<br />
Incineration Directive due <strong>to</strong> high carbon<br />
content<br />
Regional scale<br />
Level of<br />
Risk<br />
Comment<br />
Technical High Very few operating commercial plant for power<br />
or CHP.<br />
Significant residual risk in gas cleaning for<br />
power production.<br />
Substantially lower risk for gas combustion in<br />
boilers and process units.<br />
Social & Planning High High where process is used <strong>to</strong> produce<br />
electricity on a regional basis as it will be<br />
perceived as an untried form of incinera<strong>to</strong>r.<br />
Financial High Poor track record of gasification technologies.<br />
Regula<strong>to</strong>ry Medium Receives subsidy via <strong>the</strong> Renewables<br />
Obligation. Status of ash product is unclear<br />
under Waste Incineration Directive due <strong>to</strong> high<br />
carbon content.<br />
National scale<br />
Level of<br />
Risk<br />
Comment<br />
Technical Medium Little experience of biomass gasification for<br />
this application but substantial coal<br />
experience.<br />
Closely allied <strong>to</strong> refinery practice.<br />
Social & Planning Low Low for syn gas production at large scale on a<br />
petrochemical complex.<br />
Financial Medium Poor track record of gasification technologies<br />
but developers are likely <strong>to</strong> be substantial and<br />
have track record of delivery.<br />
Regula<strong>to</strong>ry Medium Receives subsidy via <strong>the</strong> Renewable transport<br />
fuels obligation. Risk for change in long lead<br />
time for build.
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10.1.2 Examples of gasification of MSW in <strong>the</strong> UK<br />
Gasification<br />
The Energos gasifier in Newport on <strong>the</strong> Isle of Wight began processing waste in mid 2008, <strong>the</strong> first<br />
example in <strong>the</strong> UK, and part of Defra’s New Technologies Demonstra<strong>to</strong>r Programme. 285 It will potentially<br />
consume 30,000 <strong>to</strong>nnes per annum of floc: an SRF baled fuel comprised of waste paper, plastic and<br />
packaging sorted from MSW. It is estimated <strong>to</strong> have a calorific content of 11-14MJ/kg. The gasification<br />
process used is a two-stage process where first <strong>the</strong> floc fuel is burnt in oxygen depleted conditions such<br />
that a gas is created. This is <strong>the</strong>n transferred <strong>to</strong> an oxidation chamber where it is <strong>full</strong>y oxidised in a<br />
controlled environment. The resulting heat from <strong>the</strong> flue gases is recovered and used <strong>to</strong> generate<br />
electricity. It is expected that <strong>the</strong> site will produce 2.3MW of electricity, and be able <strong>to</strong> deliver 1.8MW <strong>to</strong><br />
<strong>the</strong> community for use.<br />
Scotgen is part way through <strong>the</strong> construction of 40,000 <strong>to</strong>nne per annum gasification plant at Dargavel,<br />
near Dumfries. The site was due <strong>to</strong> open in March, with commissioning expected <strong>to</strong> begin in November<br />
of this year. The anticipated electrical output is 6 MW. 286<br />
A fur<strong>the</strong>r gasification site is proposed at Der<strong>by</strong>shire, UK, capable of generating 8MW of electricity through<br />
<strong>the</strong> processing of 140,000 <strong>to</strong>nnes of waste. This is joint venture between United Utilities and Interserve<br />
using Energos technology.<br />
Plasma Gasification<br />
Enviroparks Ltd, an energy company based in South Wales, have announced plans <strong>to</strong> build a number of<br />
waste treatment centres in <strong>the</strong> UK, each incorporating a plasma gasifier. The first identified site is <strong>to</strong> be<br />
at Hirwaun in Wales, and will incorporate six separate processes including recycling, material recovery<br />
and AD <strong>to</strong> treat <strong>the</strong> majority of <strong>the</strong> waste, with plasma gasification used for <strong>the</strong> residual components.<br />
It is intended that <strong>the</strong> site will process municipal and light industrial waste, converting <strong>the</strong> residual waste<br />
<strong>to</strong> an estimated 120,000MW of electricity through generation of a BioSynGas, refined through <strong>the</strong> use of<br />
plasma <strong>to</strong>rches, which will <strong>the</strong>n be used <strong>to</strong> drive a gas turbine potentially achieving efficiencies of<br />
electricity generation of 40%. This site intends <strong>to</strong> use <strong>the</strong> GHO-Power technology. The first of four<br />
announced sites <strong>to</strong> use GHO-Power technology from French company EuroPlasma, is at Morcenx in<br />
France, a 12MW power plant that will use 55,000 <strong>to</strong>nnes of general industrial waste per annum.<br />
Construction began in late 2008, and <strong>the</strong> site is intended <strong>to</strong> be operational in January 2010.<br />
10.1.3 Examples of gasification of waste wood in <strong>the</strong> UK<br />
A downdraft Gasifier plant in Tunstall, S<strong>to</strong>ke-on-Trent has been developed <strong>by</strong> Biomass Engineering Ltd<br />
and owned <strong>by</strong> O-Gen <strong>to</strong> utilise waste wood in combination with forestry wood and energy crops, intended<br />
<strong>to</strong> begin operation in 2007 and generate 8 MW of electricity. The systems uses a three-stage process,<br />
requiring fuel preparation (size and moisture), wood gasification and finally power and heat generation<br />
through combustion of <strong>the</strong> gases produced. 287<br />
Ano<strong>the</strong>r gasifier site, built <strong>by</strong> Biomass Engineering Ltd, that makes use of clean waste wood is located at<br />
Mossborough Hall in Merseyside. It is capable of generating 250kW of electricity and was connected <strong>to</strong><br />
<strong>the</strong> grid in 2005. 288<br />
285<br />
Defra Factsheet, Waste Gas Technology UK Limited (WGT), http://www.defra.gov.uk/environment/waste/wip/newtech/demprogramme/pdf/Energos.pdf<br />
286<br />
Scotgen, http://www.scotgenltd.co.uk/<br />
287<br />
O-Gen’s First Timber Resource Recovery Centre, 13/09/07, http://www.biomass.uk.com/case-study-article.php?id=172<br />
288<br />
Green Energy UK Newsletter, 2005, Mossborough Hall.<br />
155
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10.1.4 International Situation<br />
Gasification<br />
There are a few projects using <strong>the</strong> Energos technology for example <strong>the</strong> plant at Averøy in Norway. The Averøy plant<br />
opened in 2000 and processes 30,000 <strong>to</strong>nnes of MSW each year, <strong>the</strong> power output of which is used <strong>by</strong> a<br />
neighbouring fac<strong>to</strong>ry. 289 A fur<strong>the</strong>r Energos site in Norway is in Forus, receiving 40,000 <strong>to</strong>nnes per annum<br />
of residual waste since 2002.<br />
Japan has an established his<strong>to</strong>ry of gasification, with <strong>the</strong> first Thermoselect plant built at Chiba in 1999 <strong>by</strong><br />
Kawasaki Steel Corporation (now known as JFE). There are now seven plants (a <strong>to</strong>tal of 16 Thermoselect<br />
units) in operation with a <strong>to</strong>tal daily capacity of nearly 2,000 <strong>to</strong>nnes. The availability of <strong>the</strong> operating<br />
plants is about 80%. The syngas produced in <strong>the</strong> Thermoselect furnace is quenched and cleaned before<br />
it is used in gas turbines or engines. The amount of useful gas produced per <strong>to</strong>nne of MSW processed is<br />
much lower than in conventional combustion and steam generation units as cleaning a reducing gas is<br />
more complex than for combustion process gas.<br />
In <strong>the</strong> Thermoselect process waste is pushed through a heated tube. The residual char is gasified and<br />
<strong>the</strong> gases mixed, <strong>the</strong> gasification agent is oxygen which gives a high enough temperature <strong>to</strong> convert <strong>the</strong><br />
ash <strong>to</strong> slag. The mixed gases <strong>the</strong>n pass through a waste heat boiler and scrubber before being burned in<br />
a steam boiler.<br />
Currently electrical efficiencies are ra<strong>the</strong>r low at but <strong>the</strong> Japanese licensee is carrying out trials using <strong>the</strong><br />
higher calorific value gases from <strong>the</strong> reac<strong>to</strong>r with reciprocating engines and fuel cells ra<strong>the</strong>r than boilers,<br />
which should significantly improve <strong>the</strong> electrical efficiency of <strong>the</strong> process.<br />
Table 81 Thermoselect facility locations and specifications in Japan<br />
City<br />
Startup<br />
year<br />
Design<br />
Capacity<br />
(<strong>to</strong>nnes/day)<br />
Feeds<strong>to</strong>ck Syngas use<br />
Power<br />
generated<br />
Chiba 1999 2 x 165<br />
MSW +<br />
Gas engine at steelworks<br />
Industrial Waste<br />
NA<br />
Mutsu 2003 2 x 70 MSW Gas engines<br />
2 x 1.2<br />
MW<br />
Kurashiki 2005 3 x 185<br />
MSW +<br />
Gas engine at steelworks<br />
Industrial Waste<br />
NA<br />
Isahaya 2005 3 x 100 MSW Gas engines<br />
5 x 1.6<br />
MW<br />
Yokushima 2005 2 x 60 MSW Gas engines<br />
0.9 x 2<br />
MW<br />
Izumi 2005 1 x 95 Industrial Waste Boiler/Steam Turbine 1.7MW<br />
Yorii 2006 3 x 150<br />
MSW +<br />
Industrial Waste<br />
Boiler/Steam Turbine 10.5 MW<br />
Ebara’s TwinRec is a fluidized bed gasification process with ash vitrification, designed for material<br />
recycling, energy recovery and de<strong>to</strong>xification of wastes. 290 This process is capable of treating shredded<br />
residues, waste plastics, electrical waste, industrial wastes, MSW and bio-solids. The gasifier allows<br />
separates <strong>the</strong> non-combustible portion, such as metallic proportions of <strong>the</strong> waste from <strong>the</strong> combustible<br />
portion. The former is recycled as valuable products from <strong>the</strong> bot<strong>to</strong>m off-stream of <strong>the</strong> gasifier, and <strong>the</strong><br />
latter is transferred as ash, char and combustible gas <strong>to</strong> <strong>the</strong> second stage. In <strong>the</strong> second stage, fuel gas<br />
289 Homes <strong>to</strong> be powered <strong>by</strong> green power from waste, 16.04.2008, Ener.g, http://www.energ.co.uk/?OBH=490&ID=143<br />
290 TwinRec Gasification and Ash Melting Technology – Now also established for Municipal Waste , A. Selinger, Ch. Steiner and K. Shin EBARA<br />
Corporation, WASTE 2003: 4th Int. Symposium on Waste Treatment Technologies,<br />
http://www.ebara.ch/downloads/EBARA%20Manuscript%20Sheffield%20IChemE%202003.pdf
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and combustible material produced from <strong>the</strong> gasifier are burnt <strong>to</strong>ge<strong>the</strong>r in a cyclonic ash melting chamber<br />
at temperatures between 1350-1450ºC <strong>by</strong> <strong>the</strong> addition of secondary air. The particles are <strong>the</strong>n collected<br />
on <strong>the</strong> walls, where <strong>the</strong>y are vitrified and proceed slowly through <strong>the</strong> furnace.<br />
The good quality recovered metal components are sold in<strong>to</strong> <strong>the</strong> metal markets. The molten glass<br />
products fulfil <strong>the</strong> stringent Japanese soil standard and are sold <strong>to</strong> <strong>the</strong> construction industry. The energy<br />
content of <strong>the</strong> shredder residue is converted <strong>to</strong> electricity and sold <strong>to</strong> <strong>the</strong> grid.<br />
There are numerous TwinRec Fluidized Bed and Gasification facilities in Japan. Several examples are:<br />
• Ube City plant has a capacity of 8.3 <strong>to</strong>nnes per hour over three process lines and has been<br />
commercial operation since 2003. The electricity output of <strong>the</strong> plant in is 4MW. 291<br />
• Seki City plant has a capacity of 7 <strong>to</strong>nnes per hour, in commercial operation since 2003, with an<br />
electricity output.<br />
• Recently, <strong>the</strong> Kawaguchi plant was started, treating 18 <strong>to</strong>nnes per hour of municipal solid waste<br />
in three process lines (3 x 21 MW).<br />
Foster Wheeler, Lahti, Finland<br />
Lahti is a small <strong>to</strong>wn <strong>to</strong> <strong>the</strong> north of Helsinki. The <strong>to</strong>wn authority operates a 350MWth coal and natural<br />
gas fired CHP installation that provides electricity and district heating for <strong>the</strong> <strong>to</strong>wn. A 50MWth fuel-gas<br />
burner, supplied <strong>by</strong> a circulating fluid bed gasifier (see Figure 20), has been installed in place of one of<br />
<strong>the</strong> pulverised coal burners. A wide range of shredded fuels have been used with considerable success.<br />
Typical fuels are sorted domestic waste, tyres and plastic bottles, sleepers, debarker residues and<br />
sawdust. The feeds<strong>to</strong>ck is blended in an ‘A’ frame s<strong>to</strong>rage building with a traversing screw discharge.<br />
No gas clean up is used, acid gas emissions are controlled <strong>by</strong> source separation of <strong>the</strong> feeds<strong>to</strong>ck and<br />
dust from <strong>the</strong> gasifier is carried forward in<strong>to</strong> coal fired boiler and mixes with <strong>the</strong> coal ash.<br />
A detailed case study for this installation and a similar installation at Zeltweg in Austria have been<br />
prepared <strong>by</strong> <strong>the</strong> IEA Thermal Treatment of Waste Task.<br />
291 Ube, Japan, Plant Sheet, http://www.ebara.ch/downloads/ebara_plant_sheet_ube_twinrec.pdf<br />
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Figure 20 Gasifier used at Lahti<br />
Bioflow, Värnamo, Sweden<br />
Bioflow Ltd (a joint venture of Foster Wheeler and Sydkraft) has operated a demonstration plant<br />
producing approx. 6 MWe and 9 MWth for district heating. This plant has been operated using a variety<br />
of fuels, including RDF, but it is likely that <strong>the</strong> system will be targeted at biomass fuels. It is included here<br />
as an example of <strong>the</strong> concept of integrating gasification with combined cycle power generation <strong>to</strong> achieve<br />
higher electrical conversion efficiencies.<br />
The operating temperature of <strong>the</strong> gasifier is 950-1000°C at an approximate pressure of 20-22 bar. The<br />
gasifier system is based on <strong>the</strong> CFB principle (see Figure 20) with integrated cyclone and cyclone return<br />
leg. The three parts (gasifier, cyclone, cyclone return leg) are <strong>to</strong>tally refrac<strong>to</strong>ry lined. Following <strong>the</strong><br />
cyclone, <strong>the</strong> fuel-gas produced is led <strong>to</strong> a cooler and a hot gas filter. The gas cooler is of a fire tube<br />
design and cools <strong>the</strong> gas <strong>to</strong> a temperature of approximately 350°C prior <strong>to</strong> entering <strong>the</strong> filter. Following<br />
<strong>the</strong> filter <strong>the</strong> fuel-gas is burned in <strong>the</strong> combustion chambers of a single shaft industrial turbine (Als<strong>to</strong>m<br />
Typhoon). The hot flue gas from <strong>the</strong> gas turbine is ducted <strong>to</strong> <strong>the</strong> heat recovery steam genera<strong>to</strong>r.<br />
This process has <strong>the</strong> potential <strong>to</strong> deliver <strong>the</strong> highest electrical efficiency of all <strong>the</strong> options described here<br />
(40%). To do this however would require a suitable waste treatment plant <strong>to</strong> remove and recycle plastics<br />
and metals and supply a consistent fibrous fuel.<br />
SVZ Swartzepompe, Saxony, Germany<br />
This large chemical complex was built originally <strong>to</strong> convert brown coal in<strong>to</strong> a range of chemicals and fuels<br />
as part of <strong>the</strong> energy system of <strong>the</strong> former DDR (East Germany). With reunification <strong>the</strong> plant was<br />
success<strong>full</strong>y modified <strong>to</strong> accept industrial and domestic waste. In its current configuration it comprises<br />
seven fixed bed, steam/oxygen blown gasifiers operating at 25 bar and fed <strong>by</strong> a mixture of waste and<br />
coal. The complex also includes two oxygen-blown, entrained flow gasifiers that accept liquid and slurry
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wastes. The company has plans <strong>to</strong> complete <strong>the</strong> installation of a larger fixed bed British Gas/Lurgi<br />
slagging gasifier.<br />
The medium CV product gas is cleaned and used <strong>to</strong> generate electricity, through a combined cycle using<br />
a 44 MWe Als<strong>to</strong>m Turbine and a 30 MWe steam turbine. There are plans <strong>to</strong> syn<strong>the</strong>sise methanol <strong>to</strong><br />
enhance <strong>the</strong> degree of recycling that can be achieved in <strong>the</strong> installation.<br />
Current capacities are<br />
• Plastics 5 <strong>to</strong>nnes/hr<br />
• Wood 6 <strong>to</strong>nnes/hr<br />
• Liquid waste 200 <strong>to</strong>nnes/day<br />
• Domestic waste 20 <strong>to</strong>nnes/ hr<br />
All residues leave <strong>the</strong> site as inert slag<br />
This project represents a technically viable waste disposal and energy complex on a very large scale. It<br />
is an engineering success that combines a high degree of material recovery with a high electrical<br />
efficiency. It did however make substantial use of <strong>the</strong> existing brown coal processing plant so replication<br />
may prove difficult.<br />
Choren, Freiberg, Germany<br />
CHOREN Gmbh have been developing a process <strong>to</strong> produce a renewable fuel compatible with <strong>the</strong> diesel<br />
fuel infrastructure that uses lignocellulose materials. The concept is <strong>to</strong> gasify biomass and use <strong>the</strong><br />
resultant gas as a feeds<strong>to</strong>ck <strong>to</strong> syn<strong>the</strong>sise alkanes using <strong>the</strong> Fischer Tropsch reaction.<br />
The process for <strong>the</strong> gasification of wood and similar materials is based on an entrained flow gasifier used<br />
for brown coal in <strong>the</strong> 1980’s in <strong>the</strong> former DDR. The gasification process comprises two steps, slow<br />
pyrolysis of chipped material followed <strong>by</strong> <strong>the</strong> oxygen gasification of <strong>the</strong> tar vapours and char produced.<br />
The oxygen gasifier is interesting in that it is arranged in two stages; <strong>the</strong> first gasifies <strong>the</strong> pyrolysis<br />
vapours in oxygen and <strong>the</strong> second gasifies <strong>the</strong> char <strong>by</strong> reaction with <strong>the</strong> product gases from <strong>the</strong> first<br />
stage, having first been finely ground. A consequence of <strong>the</strong> second reaction is that <strong>the</strong> gasses are<br />
cooled <strong>by</strong> <strong>the</strong> endo<strong>the</strong>rmic reaction of char with CO2.<br />
The syn<strong>the</strong>sis gas from <strong>the</strong> gasifier is essentially free from tar contamination and can be cleaned <strong>by</strong><br />
filtration before <strong>the</strong> CO/H2 ratio is adjusted using <strong>the</strong> CO shift reaction. CO2 is <strong>the</strong>n removed <strong>by</strong> scrubbing<br />
and <strong>the</strong> gas passed fur<strong>the</strong>r in<strong>to</strong> <strong>the</strong> Fischer Tropsch reac<strong>to</strong>r <strong>to</strong> form a product mixture of diesel oil and<br />
naphtha.<br />
The first installation was a pilot, or alpha, plant which operated from <strong>the</strong> mid 90’s <strong>to</strong> 2005 and had a fuel<br />
input of 1MW. The second, or beta, installation is a demonstration with a fuel input of 45MW and is just<br />
undergoing commissioning and testing near Freiberg in Saxony. The third installation, or sigma, is a <strong>full</strong><br />
scale commercial unit of 640 MW which is in <strong>the</strong> design phase and should enter service in 2015.<br />
The overall energy balance of <strong>the</strong> beta demonstration unit is predicted <strong>to</strong> convert 100% fuel energy value<br />
<strong>to</strong> 39% diesel, 13% naphtha, and 6% export electricity giving an overall efficiency of 58% fuel <strong>to</strong> energy<br />
product. This is expected <strong>to</strong> improve with scale up.<br />
The development of <strong>the</strong> process is being supported <strong>by</strong> a consortium of Daimler Chrysler, Shell,<br />
Volkswagen, and o<strong>the</strong>rs with assistance from local German authorities and <strong>the</strong> EU. 292<br />
292 Start-up of <strong>the</strong> first commercial BTL production facility. Lecture <strong>by</strong> Dr. Chris<strong>to</strong>ph Kiener, Project Development Manager at <strong>the</strong> 16th European<br />
Biomass Conference & Exhibition, 3. June 2008, Valencia. www.choren.com<br />
159
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Plasma Gasification<br />
Plasma gasification is <strong>the</strong> gasification of matter in an oxygen-free environment <strong>to</strong> decompose waste<br />
material in<strong>to</strong> its basic molecular structure. It does not rely on incineration but converts organic waste in<strong>to</strong><br />
a fuel gas and inorganic waste in<strong>to</strong> an inert vitrified glass. In Japan <strong>the</strong> biggest industrial unit of its kind<br />
operates at <strong>the</strong> Eco-Valley site at Utashinai, Hokkaido plasma facility, built <strong>by</strong> Hitachi Metals. It began<br />
processing MSW in 2003 with a capacity of approximately 200-280 <strong>to</strong>ns per day. 293 It uses 8 Marc-3a<br />
plasma systems with <strong>to</strong>rches that are rated for 300 KW, operating at 2 gasification islands, each with 4<br />
<strong>to</strong>rches. The system delivers 1.5MW of net electricity output <strong>to</strong> <strong>the</strong> grid, 294 although <strong>the</strong> facility wasn’t<br />
designed with maximum power output in mind. If it had been, <strong>the</strong> predicted output would be 12MW. 295<br />
A second plasma gasification system operates in Japan, <strong>the</strong> Mihama-Mikata WTE Facility. The system<br />
gasifies 24 tpd of MSW and 4 tpd of waste-water sludge through 2 Marc-3a plasma systems. 294 The heat<br />
output is used within <strong>the</strong> waste water treatment facility.<br />
There are two plasma gasification plants under construction in India, at Pune and Nagpur, both intended<br />
<strong>to</strong> take 72 <strong>to</strong>ns per day of hazardous waste and convert it <strong>to</strong> energy.<br />
A plasma gasifier has planning permission in <strong>the</strong> USA, Florida where it is intended that 3,000 <strong>to</strong>ns per<br />
day of MSW will be converted <strong>to</strong> 120MW of electricity and is expected <strong>to</strong> be operational in 2010. 296<br />
10.2 Pyrolysis<br />
SRF<br />
Waste wood<br />
Clean wood<br />
Pyrolysis<br />
Gas<br />
Pyrolysis oils<br />
Char<br />
Process Description<br />
Pyrolysis is normally defined as <strong>the</strong> <strong>the</strong>rmal degradation of a substance in <strong>the</strong> absence of any oxidising<br />
agent (o<strong>the</strong>r than that which forms part of <strong>the</strong> substance itself) <strong>to</strong> produce char and one or both of gas<br />
and liquid.<br />
The process converts feeds<strong>to</strong>ck waste in<strong>to</strong> char, vapours of complex carbohydrates and permanent<br />
gases, primarily CO, H2, CH4 and CO2. This is done <strong>by</strong> <strong>the</strong> action of heat in oxygen free conditions at<br />
high temperatures between 400°C and 900°C. The proportions of <strong>the</strong> three product classes depend upon<br />
CHP<br />
293 Eco-Valley Waste-<strong>to</strong>-Energy Facility, http://www.alternrg.ca/project_development/commercial_projects/utashinai<br />
294 Alter Nrg and Westinghouse Plasma Corp: The Plasma Gasification Process, February, 2008,<br />
http://www.calgaryregion.ca/crp/media/32152/<strong>the</strong>_alter_nrg_plasma_gasification_process_-_turner_valley_presentation.ppt.pdf<br />
295 Westinghouse Plasma Corporation, Waste Processing, http://www.westinghouse-plasma.com/markets_applications/waste_processing.php<br />
296 Westinghouse Plasma Corporation, www.westinghouse-plasma.com/common/pdfs/WPC.pdf<br />
Slurry<br />
Thermochemical<br />
Fuel<br />
Heat<br />
Power
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<strong>the</strong> temperature of <strong>the</strong> reac<strong>to</strong>r and critically <strong>the</strong> rate at which heat is applied <strong>to</strong> <strong>the</strong> biomass fractions.<br />
Lower temperatures and fast heating rates favour vapours, higher temperatures and high heating rates<br />
gas, low temperature and slow heating rates favour char formation.<br />
There are two main categories of pyrolysis process, but many practical variants within <strong>the</strong>m:<br />
Fast or flash pyrolysis – typically finely divided biomass waste is injected in<strong>to</strong> a fluidised bed of inert<br />
material operating at 500°C. The size of <strong>the</strong> fuel and <strong>the</strong> excellent heat transfer characteristics of <strong>the</strong> fluid<br />
bed ensure a very fast heating rate which maximises <strong>the</strong> production of vapour. The vapour is<br />
subsequently condensed as a liquid that contains approximately 70% of <strong>the</strong> energy value of <strong>the</strong> waste<br />
feeds<strong>to</strong>ck. The <strong>by</strong>-product char and gas is used in part <strong>to</strong> provide heat <strong>to</strong> drive <strong>the</strong> process. The liquid<br />
fuel has been success<strong>full</strong>y used <strong>to</strong> fire boilers and kilns. Trials have been undertaken in reciprocating<br />
engines and gas turbines. Excess char can be sold as a product for activated carbon manufacture or<br />
reducing agent in metal production. The char can also be used as fuel ei<strong>the</strong>r on its own or as a slurry<br />
with <strong>the</strong> pyrolysis liquids.<br />
The main use for fast pyrolysis processes at present is <strong>the</strong> manufacture of speciality chemicals and food<br />
additives although this is expected <strong>to</strong> change <strong>to</strong> energy use when <strong>the</strong> current demonstration plants in<br />
Canada come <strong>full</strong>y on stream.<br />
Slow Pyrolysis – finely diced waste is pyrolysed in ei<strong>the</strong>r in a screw conveyor or reac<strong>to</strong>r vessel that is<br />
indirectly heated. The slower heating rate favours char and liquid production over gas.<br />
Carbonisation – large pieces of waste or wood are heated in a re<strong>to</strong>rt. The heat is provided <strong>by</strong> burning a<br />
proportion of <strong>the</strong> vapour and gas product.<br />
A variation of slow pyrolysis using a heated screw has recently been proposed as a step in <strong>the</strong> production<br />
of <strong>the</strong>rmo chemical fuels in <strong>the</strong> form of a slurry of charcoal and pyrolysis liquid product. The concept is a<br />
series of distributed fuel preparation processes on a local and regional scale that feed supply a very large<br />
gasification plant at national scale. The advantages are reduced transport costs and having <strong>the</strong> fuel in a<br />
form that it can easily be pumped in<strong>to</strong> <strong>the</strong> high pressure (60 bar) processes that are used in this type of<br />
facility.<br />
Feeds<strong>to</strong>cks for Pyrolysis<br />
Currently fast pyrolysis processes are being designed for both clean wood and wood extracted from <strong>the</strong><br />
waste stream. In all cases <strong>the</strong> wood will need <strong>to</strong> be ground <strong>to</strong> less that 3mm particle size before use.<br />
Slow pyrolysis can use a wider variety of solid shredded material including SRF.<br />
Table 82 Risks Associated with Pyrolysis<br />
Level of Risk Comment<br />
Technical High Operating commercial plant in existence for oil<br />
production little experience in energy generation.<br />
Social & Planning High / Low High where process is used <strong>to</strong> produce electricity<br />
at a regional scale where it may be perceived as<br />
an untried and unsafe incinera<strong>to</strong>r.<br />
Low for syn gas production or <strong>the</strong>rmo chemical<br />
fuel production where it wuill be perceived as<br />
ano<strong>the</strong>r industrial process.<br />
Financial High Few suppliers and uneven track record.<br />
Products have no established energy market and<br />
would rely on dedicated cus<strong>to</strong>mer.<br />
Regula<strong>to</strong>ry Medium Receives enhanced subsidy via <strong>the</strong> Renewables<br />
Obligation.<br />
Status of products is unclear.<br />
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10.2.1 Pyrolysis in <strong>the</strong> UK<br />
Seamer Carr, Scarborough<br />
The UK’s first <strong>full</strong> scale waste pyrolysis plant is <strong>to</strong> be known as Scarborough Power Ltd. Once<br />
operational <strong>the</strong> plant will consume 18,000 <strong>to</strong>nnes per annum of high calorific value pre-sorted MSW, i.e. a<br />
form of SRF. 297 After shredding and drying <strong>the</strong> expected calorific content of this material will be 15MJ/kg.<br />
Simple flash pyrolysis, with technology provided <strong>by</strong> GEM, will be used <strong>to</strong> convert <strong>the</strong> waste <strong>to</strong> syngas in<br />
<strong>the</strong> absence of oxygen, which is <strong>the</strong>n ultimately used <strong>to</strong> generate electricity and heat, expected <strong>to</strong> be<br />
2.4MW of electricity and 1.8MW of gross heat output.<br />
This project is a joint venture between Yorwaste, pyrolysis technology company GEM, and engineering<br />
consultancy NEL Power, and is part of Defra’s New Technologies Demonstration Programme.<br />
Compact Power, Avonmouth<br />
The Compact Power process is typical of a heated tube system. The schematic (Figure 21) shows <strong>the</strong><br />
company’s 8,000 <strong>to</strong>nnes per annum demonstration plant at Avonmouth. This plant is intended for <strong>the</strong><br />
treatment of MSW and clinical waste. Waste may be first sorted <strong>to</strong> remove recyclables. It is <strong>the</strong>n<br />
conveyed <strong>by</strong> a screw through a heated tube where it pyrolyses. The pyrolysis gases are <strong>the</strong>n burned in a<br />
cyclone combustion chamber. The residual char falls in<strong>to</strong> a hopper where it is gasified <strong>by</strong> steam that has<br />
been preheated in <strong>the</strong> combustion chamber, leaving an ash residue. The gas from <strong>the</strong> gasification<br />
section is burned with <strong>the</strong> pyrolysis gas. The hot gas from <strong>the</strong> combustion chamber is first used <strong>to</strong> heat<br />
<strong>the</strong> pyrolysis tubes <strong>the</strong>n <strong>to</strong> raise steam for power generation. Flue gas clean up is after <strong>the</strong> boiler and<br />
uses a dry bicarbonate injection system. The residue is <strong>report</strong>ed as a dry, inert gas. The emissions<br />
performance is <strong>report</strong>ed as excellent with most regulated pollutants an order of magnitude below <strong>the</strong><br />
statu<strong>to</strong>ry limit.<br />
The focus is largely on waste disposal at an acceptable cost on a small scale appropriate <strong>to</strong> clinical and<br />
industrial wastes, and smaller urban communities. As such it fits well with recycling schemes. Energy<br />
recovery is currently relatively low and comparable with combustion systems. More development would<br />
be necessary <strong>to</strong> take advantage of <strong>the</strong> higher efficiencies offered <strong>by</strong> gas turbine and reciprocating engine<br />
cycles.<br />
Figure 21 Schematic of Compact Power’s demonstration plant at Avonmouth<br />
297 Defra Factsheet, Scarborough Power, http://www.defra.gov.uk/environment/waste/wip/newtech/dem-programme/pdf/Scarborough-Power.pdf
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The Avonmouth Pyrolysis and Gasification Plant near Bris<strong>to</strong>l, is <strong>the</strong> next step in <strong>the</strong> development path for<br />
this technology but has experienced difficulties with <strong>the</strong> original owners Compact Power went in<strong>to</strong><br />
administration in 2008 and Ethos Recycling bought <strong>the</strong> site. Assuming <strong>the</strong> site does become operational,<br />
it will be capable of processing 30,000 <strong>to</strong>nnes of waste per annum, generating 2,400 kW of electricity and<br />
7,620 kW of heat. 298<br />
10.2.2 International experience<br />
R21 process<br />
Mitsui Babcock Energy runs a number of R21 (Recycling in <strong>the</strong> Twenty First Century) Pyrolysis<br />
Technology facilities in Japan. These facilities rely on a pre-incineration pyrolysis process operated at<br />
low temperature (less than 450ºC) of MSW, which converts poor fuel (such as MSW) in<strong>to</strong> high value<br />
product fuels such as syngas and a solid residue. These products are <strong>the</strong>n combusted at high<br />
temperatures (1300ºC) and efficiencies, from which heat recovery occurs <strong>to</strong> produce heat or power<br />
output. Applying this technology <strong>to</strong> MSW means that <strong>the</strong> waste can be burnt in much better combustion<br />
conditions, reducing <strong>the</strong> potential for dioxin production, NOx and <strong>the</strong> dry slag produced is vitrified inert,<br />
carbon and dioxin free.<br />
Typically, a 100,000tpa R21 plant treating MSW with a calorific value of 9.5MJ/kg will produce 8MW gross<br />
electrical output per <strong>to</strong>nne of MSW 299 . Some of this electrical energy is used in house <strong>to</strong> drive <strong>the</strong> process<br />
reducing this figure <strong>to</strong> 5.1MW net electrical output per <strong>to</strong>nne MSW. Table 83 cites some of <strong>the</strong><br />
commercially operating facilities <strong>by</strong> Mitsui Babcock Energy Ltd in Japan. 299 The focus in Japan is<br />
currently very much on waste disposal and recovery of material ra<strong>the</strong>r than energy.<br />
.<br />
Table 83 Examples of commercially operating R21 facilities <strong>by</strong> Mitsui Babcock Energy<br />
Location Capacity (<strong>to</strong>nnes/day)<br />
Aichi/ Toyohashi City 220tpd over 2 trains<br />
Hokkaido / Ebetsu City 140tpd over 2 trains<br />
Fukuoka / Koga Seibu<br />
Regional Cooperative 260tpd over 2 trains<br />
298<br />
The Avonmouth Renewable Energy Plant, Defra Factsheet, http://www.defra.gov.uk/environment/waste/wip/newtech/demprogramme/pdf/Avonmouth.pdf<br />
299<br />
Mitsui Babcock Energy Limited Submission <strong>to</strong> Greater London Authority City Solutions Stakeholders On Municipal Waste Management, 2003,<br />
http://www.london.gov.uk/mayor/environment/waste/wasteconfdocs/Mitsui.pdf<br />
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Figure 22 A schematic of <strong>the</strong> Toyohashi R21 system<br />
Coke-Oven<br />
A process developed <strong>by</strong> Nippon Steel converts waste plastic in<strong>to</strong> energy, <strong>the</strong> “Coke-Oven from Waste<br />
Plastics <strong>to</strong> Chemical Raw Materials Method”. This method uses a chemical recycling process <strong>to</strong> recover<br />
coke, tar, light oil and gas from general wastes plastics mixed in coal <strong>by</strong> carbonisation of coke ovens<br />
without deteriorating <strong>the</strong> quality of coke. The yield from this process is approximately 20% of coke, 40%<br />
tar and light oil, and 40% gases. The recovered coke is used <strong>to</strong> reduce <strong>the</strong> iron ore in a blast furnace, <strong>the</strong><br />
tar and light oil as raw material for making plastic and <strong>the</strong> gas in a power plant. A number of such<br />
facilities exist in Japan, and shown in Table 84. Nippon Steel have recently filed a patent for a process<br />
which would give a product with greater utility value. 300<br />
Table 84 List of Coke-Oven from Waste Plastics <strong>to</strong> Chemical Raw Materials Method facilities<br />
Year Capacity<br />
City<br />
<strong>to</strong>nnes p.a.<br />
Nagoya 2000 40,000<br />
Kimitsu 2000 40,000<br />
Muroran 2002 20,000<br />
Yawata 2002 20,000<br />
300 Method and Apparatus for Thermal Decomposition of Waste Plastics, JP2008266452 (A), Nippon Steel Corporation, 06.11.2008.
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As is demonstrated <strong>by</strong> <strong>the</strong> above examples, in terms of <strong>the</strong>rmal treatment of waste Japan, has a wellestablished<br />
system in place. Now <strong>the</strong> agenda has begun <strong>to</strong> shift <strong>to</strong>wards <strong>the</strong> generation of energy as well<br />
as waste minimisation, Japan is one of <strong>the</strong> leading countries in terms of technology development and has<br />
<strong>the</strong> largest number of plants in operation that use <strong>the</strong>rmal conversion techniques <strong>to</strong> treat waste and<br />
recover energy.<br />
10.3 Conclusions<br />
From this review <strong>the</strong> following conclusions can be drawn;<br />
• Combustion, gasification and pyrolysis all use heat <strong>to</strong> break down <strong>the</strong> structure of <strong>the</strong> feeds<strong>to</strong>ck<br />
so that <strong>the</strong> chemical energy can be released ei<strong>the</strong>r as heat or a fuel product. The conditions in<br />
<strong>the</strong> reac<strong>to</strong>r determine <strong>the</strong> products.<br />
• Gasification technologies are being developed but often encounter severe technical difficulties<br />
when attempting <strong>the</strong> step of using <strong>the</strong> gas for power generation in an engine or gas turbine.<br />
• The robust approach of firing <strong>the</strong> gas in a boiler is proving reliable and a worthwhile innovation.<br />
These units can be produced in smaller sizes than conventional incineration and can be matched<br />
<strong>to</strong> heat loads in CHP and process heating applications <strong>to</strong> give potentially <strong>the</strong> best GHG<br />
abatement potential.<br />
• Gasification as a pre-treatment is likely <strong>to</strong> become more popular in cofiring as genera<strong>to</strong>rs seek <strong>to</strong><br />
increase <strong>the</strong> proportion of biomass in coal fired utility boilers.<br />
• There are few commercial pyrolysis plant operating on waste.<br />
• The technologies available for conversion of waste <strong>to</strong> heat and power are more widesp<strong>read</strong> than<br />
those for conversion <strong>to</strong> transport fuels, although work is ongoing on advanced conversion for<br />
liquid biofuels.<br />
• The use of gasification at very large scale for <strong>the</strong> production of transport fuels or pipeline<br />
methane is attracting increasing attention and is potentially an efficient use of resources.<br />
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11 Potential GHG Reductions<br />
Wastes arisings in <strong>the</strong> UK represent a potential resource and feeds<strong>to</strong>ck available <strong>to</strong> be converted in<strong>to</strong><br />
products for fur<strong>the</strong>r use. Assessing <strong>the</strong> most environmentally friendly disposal option for a particular<br />
waste can be challenging as <strong>the</strong>re are often a range of disposal options available and limited data on<br />
which <strong>to</strong> base assumptions of potential environmental costs and benefits.<br />
The key advantage of utilising waste materials for <strong>the</strong> generation of energy or transport fuels is that <strong>the</strong>y<br />
displace <strong>the</strong> use of fossil fuels and divert material that would o<strong>the</strong>rwise likely be disposed of <strong>to</strong> landfill.<br />
The quantification of <strong>the</strong> environmental costs and benefits is required <strong>to</strong> ensure <strong>the</strong> most appropriate<br />
solutions are developed. Recent work performed <strong>by</strong> AEA and North Energy for <strong>the</strong> EU Commission, DG<br />
Environment (awaiting publication) has identified that ‘waste-based bio-energy pathways offer <strong>the</strong> highest<br />
GHG emissions savings’. 301 This is due <strong>to</strong> <strong>the</strong> absence of production emissions for <strong>the</strong> material, and <strong>the</strong><br />
displaced fossil fuels.<br />
Below, two scenarios of converting a waste material <strong>to</strong> energy or a transport fuel, and <strong>the</strong> GHG savings<br />
such conversions would achieve, have been explored:<br />
• Converting source separated food waste, through anaerobic digestion, <strong>to</strong> a digestate and a<br />
biogas, and subsequently converting this biogas <strong>to</strong> CHP, electricity or alternatively a transport<br />
fuel.<br />
• Converting waste wood, through combustion, <strong>to</strong> electricity.<br />
These scenarios were selected <strong>to</strong> complement our identification of <strong>the</strong>se feeds<strong>to</strong>cks in Section 5 as likely<br />
<strong>to</strong> make a substantial contribution <strong>to</strong> renewable energy from wastes in <strong>the</strong> future. They also illustrate <strong>the</strong><br />
insights that can be gained through this type of analysis as <strong>the</strong>y cover an extensive life cycle extending in<br />
<strong>to</strong> feeds<strong>to</strong>ck supply and alternative uses.<br />
Both scenarios are been explored through <strong>the</strong> use of BEAT.<br />
Box 4: Biomass Environmental Assessment Tool (BEAT)<br />
BEAT was originally developed for <strong>the</strong> UK Department for Environment, Food and Rural Affairs<br />
(Defra) and <strong>the</strong> UK Environment Agency (EA). Hence, <strong>the</strong> nature of <strong>the</strong> technologies, performance<br />
characteristics and related assumptions are based on UK circumstances.<br />
It is designed <strong>to</strong> provide a means of assessing biomass schemes <strong>by</strong>:<br />
1. Providing a comparison of GHG emissions from <strong>the</strong> proposed plant and fossil fuel based plant;<br />
2. Providing information on key potential environmental impacts;<br />
3. Identifying potential options for mitigating environmental impacts;<br />
4. Providing an estimate of production costs and of support mechanisms.<br />
While <strong>the</strong> <strong>to</strong>ol can consider all stages of <strong>the</strong> fuel chain, modification of <strong>the</strong> analysis is <strong>read</strong>ily<br />
achievable through altering <strong>the</strong> system boundaries and <strong>the</strong> reference pathway.<br />
BEAT was launched on 13th November 2008, when <strong>the</strong> <strong>to</strong>ol/dataset were also made publicly available.<br />
Beat is available from <strong>the</strong> Biomass Energy Centre www.biomassenergycentre.org.uk.<br />
301 Implementation of <strong>the</strong> EU Biomass Action Plan and <strong>the</strong> Biofuel Strategy: Comparing GHG emission reduction performance of different bio-energy<br />
applications on a life cycle basis, AEA and North Energy,
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Some of <strong>the</strong> key features of <strong>the</strong> BEAT systems and <strong>the</strong> criteria that have been used here are:<br />
• System boundary: In this work <strong>the</strong> systems begin at <strong>the</strong> point <strong>the</strong> waste is available for use as a<br />
resource, taking no consideration of <strong>the</strong> environmental impacts of creating <strong>the</strong> waste. Once use<br />
of <strong>the</strong> waste as a feeds<strong>to</strong>ck commences all subsequent stages are incorporated, e.g. emissions<br />
from processing <strong>the</strong> waste, manufacture of machinery and ash disposal, <strong>to</strong> cite a few stages.<br />
• GHG Emissions: Emissions of <strong>the</strong> three main GHGs, carbon dioxide (CO2), methane (CH4) and<br />
nitrous oxide (N2O) are included. While carbon dioxide and, <strong>to</strong> a lesser extent, methane<br />
emissions are widely publicised, sources of nitrogen giving rise <strong>to</strong> <strong>the</strong> emission of nitrous oxide<br />
(N2O) from <strong>the</strong> soil is a less well known effect. A complex series of reactions and processes<br />
transform some of <strong>the</strong> nitrogen present in<strong>to</strong> N2O, potentially a critical issue as <strong>the</strong> global warming<br />
potential of N2O is nearly 300 times that of CO2. Individual GHG emissions are converted in<strong>to</strong><br />
equivalent CO2 using quoted values of Global Warming Potentials (GWPs).<br />
• CHP: In all cases emissions savings have been derived assuming <strong>the</strong> displacement of<br />
compressed natural gas, or <strong>the</strong> displacement of grid electricity.<br />
• Reference system: Reference systems are used here <strong>to</strong> address <strong>the</strong> alternative fate of a waste<br />
product. The disposal of a waste product will be avoided if it is used as a biomass feeds<strong>to</strong>ck for<br />
energy production. The GHG emissions that would have arisen from disposal are taken in<strong>to</strong><br />
account <strong>by</strong> deducting from <strong>the</strong> <strong>to</strong>tal GHG emissions of <strong>the</strong> pathway.<br />
• Fossil Fuel Displacement: Assumptions about <strong>the</strong> fossil fuel displaced (e.g. coal, oil, or gas) and<br />
<strong>the</strong> efficiency of <strong>the</strong> conversion technology for heat and electricity production can make a<br />
significant difference <strong>to</strong> <strong>the</strong> savings calculated.<br />
Using BEAT <strong>to</strong> follow <strong>the</strong> two waste disposal scenarios outlined below allow establishment of <strong>the</strong><br />
potential GHG reductions that could be achieved were <strong>the</strong> alternative disposal route <strong>to</strong> be pursued and<br />
<strong>the</strong> final products <strong>full</strong>y utilised.<br />
The results have been presented in terms of <strong>the</strong> kilograms of GHG saved per <strong>to</strong>nne of waste, as waste<br />
utilisation is <strong>the</strong> primary aim, with energy generation <strong>the</strong> secondary aim.<br />
11.1 Scenario 1: Food Waste<br />
Domestic food waste can be collected separately as part of <strong>the</strong> MSW disposal route. This waste<br />
represents a resource that can be widely available throughout <strong>the</strong> UK, although collection and transport<br />
are likely <strong>to</strong> be more efficient in urban areas. It is estimated that <strong>the</strong>re is potentially 5 million <strong>to</strong>nnes of<br />
MSW food waste each year, as well as nearly 7 million <strong>to</strong>nnes of C&I food waste (for England, Wales and<br />
Scotland), although it is unlikely all would be available for collection.<br />
The majority of this waste stream currently goes <strong>to</strong> landfill, often with energy recovery through landfill gas.<br />
This situation is rapidly changing with <strong>the</strong> requirement of <strong>the</strong> Landfill Directive that levels of biodegradable<br />
municipal solid waste (MSW) sent <strong>to</strong> landfill must be reduced <strong>to</strong> 75% <strong>by</strong> 2010, <strong>by</strong> 50% 2013 and <strong>by</strong> 35%<br />
<strong>by</strong> 2020 of 1995 levels. The alternative disposal options available are <strong>to</strong> compost or anaerobically digest<br />
<strong>the</strong> waste.<br />
Food waste treated at a compost site will produce a soil conditioner material. The composting process<br />
will be required <strong>to</strong> be carried out in a sealed container as <strong>the</strong> material may contain meat or meat<br />
products.<br />
Food waste treated at an AD site will produce an organic digestate output, which can be used as a soil<br />
conditioner. It has been assumed that a compost soil conditioner and a digestate soil conditioner,<br />
although having different physical forms, have <strong>the</strong> same value as a soil conditioner. In addition biogas<br />
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will be produced which, depending on <strong>the</strong> properties of <strong>the</strong> input material, can be expected <strong>to</strong> contain<br />
approximately 40% carbon dioxide and 60% methane. The biogas can be upgraded, cleaned,<br />
compressed and ultimately converted in<strong>to</strong> a transport fuel.<br />
MSW Food<br />
Waste<br />
Biodegradation<br />
Composting<br />
Anaerobic<br />
Digestion<br />
Landfill<br />
With landfill gas<br />
Compost<br />
Digestate<br />
Biogas<br />
Cleaning and<br />
Compression<br />
Figure 23 Disposal options for food waste<br />
Transport<br />
Gas<br />
While disposal <strong>to</strong> landfill is <strong>the</strong> current most likely route, composting is likely <strong>to</strong> become <strong>the</strong> norm in <strong>the</strong><br />
near future. Therefore <strong>the</strong> utilisation of waste food has been explored predominately with <strong>the</strong> reference<br />
system set as in vessel compositing:<br />
1. The GHG savings an AD disposal route would generate, with <strong>the</strong> biogas produced used for:<br />
a. heat and electricity generation,<br />
b. electricity generation,<br />
c. <strong>the</strong> biogas used for vehicle transport, with additional cleaning and compression stages.<br />
In addition a comparison reference system of disposal <strong>to</strong> landfill has been run:<br />
2. The GHG savings an AD disposal route would generate, with landfill disposal used as <strong>the</strong><br />
reference system with <strong>the</strong> biogas produced used for:<br />
a. electricity generation.
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Table 85 Comparing AD disposal of food waste against in vessel composting<br />
End Use<br />
1a<br />
GHG savings<br />
kg CO2eq /<br />
<strong>to</strong>nne biomass<br />
• Centralised AD for CHP using 90,000<br />
<strong>to</strong>nnes food waste per annum.<br />
104<br />
• 1.7MWe and 4MWth exported.<br />
• 75% efficiency at 55% load.<br />
1b<br />
• Centralised AD for electricity using 90,000<br />
<strong>to</strong>nnes food waste per annum.<br />
• 2.8MWe exported<br />
• 25% efficiency at 70% load<br />
1c<br />
• Centralised AD for biomethane production<br />
from 90,000 <strong>to</strong>nnes of food waste per<br />
annum, <strong>to</strong> be used for vehicle transport.<br />
• 28,000MWth per annum biomethane<br />
produced.<br />
The centralised AD systems generating energy, one generating CHP, <strong>the</strong> o<strong>the</strong>r only electricity, can be<br />
considered as economically feasible where gate fees can be charged. The conversion of <strong>the</strong> biogas in<strong>to</strong><br />
a transport gas is not commercial currently in <strong>the</strong> UK.<br />
The benefits of composting food waste or anaerobically digesting it are broadly similar. The additional<br />
significant benefit of AD systems is <strong>the</strong> use of <strong>the</strong> biogas <strong>to</strong> displace fossil fuel use. Although <strong>the</strong>re is<br />
some variation between <strong>the</strong> above scenarios, all three represent significant GHG savings versus <strong>the</strong><br />
composting of <strong>the</strong> waste. The CHP scenario assumes 100% utilisation of <strong>the</strong> heat produced, a utilisation<br />
level that may be challenging <strong>to</strong> meet, and correspondingly <strong>the</strong> real-world GHG savings are more likely <strong>to</strong><br />
be comparable with those for electricity generation or transport fuel generation.<br />
Table 86 Comparing AD disposal of food waste against landfill disposal, with landfill gas recovery<br />
End Use GHG savings*<br />
(Kg CO2eq / T)<br />
2a<br />
• Centralised AD for electricity using 90,000 <strong>to</strong>nnes<br />
food waste per annum.<br />
219<br />
• 10MWe exported<br />
• 25% efficiency at 70% load<br />
Significant GHG emissions still occur through using AD, such as methane leakage from <strong>the</strong> system and<br />
N2O generation from <strong>the</strong> sp<strong>read</strong>ing and incorporation of <strong>the</strong> digestate in<strong>to</strong> soil. However, even taking<br />
such effects in<strong>to</strong> account, it can be concluded that using AD <strong>to</strong> dispose of food waste, with electricity<br />
generation from <strong>the</strong> biogas, large GHG savings are generated, versus disposal <strong>to</strong> land fill.<br />
Where use of AD disposal routes is compared <strong>to</strong> in-vessel composting, significant GHG savings are also<br />
achieved, whe<strong>the</strong>r <strong>the</strong> biogas is used for CHP, electricity generation or as a transport fuel. The most<br />
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significant saving is if <strong>the</strong> biogas is used for CHP and highly efficient use of <strong>the</strong> heat generated is<br />
achieved.<br />
11.2 Scenario 2: Wood Waste<br />
Wood waste is taken here <strong>to</strong> be wood that is contaminated, ei<strong>the</strong>r impregnated with preservatives, or<br />
coated with paints and varnished. Disposal <strong>the</strong>refore requires WID compliant facilities, and currently only<br />
<strong>the</strong> largest of facilities have appropriate emissions cleaning facilities. While a considerable quantity of<br />
such material is estimated <strong>to</strong> be disposed of each year, <strong>the</strong>re is little good quality data for this waste<br />
stream. Estimations from WRAP put <strong>the</strong> volume of wood waste at 1,065,000 <strong>to</strong>nnes from MSW, 602,000<br />
<strong>to</strong>nnes from waste furniture, 4,400,000 <strong>to</strong>nnes from C&D waste (5,040,000 if include reclaimed wood),<br />
and 4,481,000 <strong>to</strong>nnes from C&I waste. This would potentially offer 10,548,000 <strong>to</strong>nnes of wood waste a<br />
year.<br />
The options available for <strong>the</strong> disposal of wood waste are for it <strong>to</strong> be sent <strong>to</strong> landfill or for it <strong>to</strong> be<br />
segregated and used as a feeds<strong>to</strong>ck for combustion, generating heat, CHP or electricity. An alternative<br />
possibility is for a conversion process <strong>to</strong> be used, such as gasification followed <strong>by</strong> Fischer Tropsch <strong>to</strong><br />
generate a transport fuel. This however hasn’t been modelled as we have been unable <strong>to</strong> identify<br />
sufficient data on using wood waste as a feeds<strong>to</strong>ck for this process.<br />
Waste Wood<br />
Combustion<br />
Landfill<br />
With landfill gas<br />
Heat, CHP<br />
or Electricity<br />
Figure 24 Disposal options for waste wood<br />
It is assumed that most wood waste is disposed of <strong>to</strong> landfill with energy recovery. Such a scenario has<br />
not been taken as <strong>the</strong> reference system for this work as <strong>the</strong> intention here is <strong>to</strong> compare <strong>the</strong> different end<br />
uses of waste wood, and comparison <strong>to</strong> landfilling can generates large negatives that do not allow<br />
accurate comparison. In <strong>the</strong> following situations <strong>the</strong> GHG savings come from <strong>the</strong> displaced fossil fuel, in<br />
each case natural gas, so once again giving a conservative estimate of <strong>the</strong> savings generated.<br />
Two different scenarios considering <strong>the</strong> GHG saving that could be achieved from using waste wood as a<br />
feeds<strong>to</strong>ck for energy generation.<br />
1. Industrial or commercial building heating. This system is al<strong>read</strong>y economic, but still has<br />
challenges <strong>to</strong> face including WID compliant facilities, fuel s<strong>to</strong>rage and ash disposal.<br />
2. Combustion in a medium scale plant – <strong>the</strong> practical limit for waste levels generated within an<br />
RDA geographical region. Such a system would be economic with <strong>the</strong> currently available<br />
subsidy i.e. <strong>the</strong> availability of 1.5 ROC.<br />
Both systems have been considered in terms of <strong>the</strong> displacement of natural gas as <strong>the</strong> fossil fuel<br />
equivalent and are estimated <strong>to</strong> would produce <strong>the</strong> following GHG savings:
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Table 87 Combustion of wood waste and <strong>the</strong> savings generated from avoided fossil fuel consumption<br />
End Use GHG savings<br />
(Kg CO2eq / <strong>to</strong>nne of<br />
biomass)<br />
• Industrial or Commercial building heating<br />
• 500kW boiler using wood chips<br />
1,040<br />
• Operating at 33% load<br />
• Medium combustion plant<br />
• 50MWe exported<br />
450<br />
• 85% load.<br />
Significant GHG savings would be achieved were wood waste <strong>to</strong> be used as a fuel source for<br />
combustion, ra<strong>the</strong>r than disposal <strong>to</strong> landfill.<br />
11.3 O<strong>the</strong>r, recent GHG life cycle analyses<br />
Recent work <strong>by</strong> <strong>the</strong> Environment Agency has analysed a wide range of biomass energy cycles using <strong>the</strong><br />
BEAT <strong>to</strong>ol. Such cycles take in <strong>to</strong> account <strong>the</strong> fate of <strong>by</strong>-products and <strong>the</strong> production of <strong>the</strong> fuel. The<br />
main findings of this work are that<br />
• Heat applications are <strong>the</strong> most beneficial in terms of GHG abatement followed <strong>by</strong> CHP where <strong>the</strong><br />
heat load is high.<br />
• Transport fuel production <strong>by</strong> means of gasification is mid range.<br />
• Electricity production comes lower in <strong>the</strong> hierarchy as do biological transport fuel processes and<br />
low heat load CHP.<br />
What is interesting from this work is that it is <strong>the</strong> resource use efficiency <strong>to</strong> energy that is <strong>the</strong> determining<br />
fac<strong>to</strong>r, so that heat will always score highly because it converts over 90% of <strong>the</strong> energy of <strong>the</strong> feeds<strong>to</strong>ck<br />
in<strong>to</strong> usable heat. The performance of CHP is very dependent on <strong>the</strong> heat load; industrial process heat<br />
loads score well but minimal application of district heat scores badly.<br />
Given <strong>the</strong> high resource use efficiency gasification and methanation should be very beneficial if <strong>the</strong> high<br />
grade heat from <strong>the</strong> exo<strong>the</strong>rmal reaction is <strong>full</strong>y used, however <strong>the</strong>re is no data on <strong>the</strong>se systems at<br />
present.<br />
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12 Recommendations and NNFCC’s role<br />
Challenges, issues and <strong>the</strong> role of NNFCC<br />
Throughout this <strong>report</strong> we have identified areas of uncertainty, and specific challenges that need work if<br />
<strong>the</strong> <strong>full</strong> potential of energy from waste is <strong>to</strong> be realised. These are set out in <strong>the</strong> table below. Most of<br />
<strong>the</strong>se are concerned with building business confidence in <strong>the</strong> links between each of <strong>the</strong> technology steps.<br />
Not all of this work will come under NNFCC’s remit but a significant amount is concerned with<br />
coordination of stakeholders and <strong>the</strong> provision of information <strong>to</strong> <strong>the</strong> market.<br />
Those <strong>to</strong>pics we feel are most appropriate for NNFCC initiatives are as follows:<br />
• Improve quality of policy and investment decision making <strong>by</strong> developing an understanding of <strong>the</strong><br />
fit between SRF properties and energy production technologies. What properties does each of<br />
<strong>the</strong> technologies require?<br />
• There is a wide difference in <strong>the</strong> benefits brought <strong>by</strong> various waste <strong>to</strong> energy chains and it is<br />
important that policy support those that contribute <strong>the</strong> most. NNFCC could add value <strong>by</strong><br />
developing an evidence base for <strong>the</strong> design and implementation of policy and a hierarchy of uses<br />
for each class of resource based on environmental and social benefits including life cycle GHG<br />
impact.<br />
• To maximise <strong>the</strong> benefits of using waste for energy we will need <strong>to</strong> change current practices<br />
across a wide range of stakeholders. NNFCC could add value <strong>by</strong> developing an understanding of<br />
<strong>the</strong> relative timeframes of structural changes and technology developments necessary <strong>to</strong><br />
maximise implementation.<br />
• Develop a better understanding of <strong>the</strong> impacts of increased energy usage on alternative and<br />
existing markets for straw and o<strong>the</strong>r residues.<br />
• NNFCC could consider <strong>the</strong> logistics of moving dispersed low density feeds<strong>to</strong>cks around <strong>the</strong> UK,<br />
taking a role <strong>to</strong> assess options for transport modes and evaluate <strong>the</strong> optimal size of plants for <strong>the</strong><br />
various feeds<strong>to</strong>cks.<br />
• Municipal and solid waste is being managed using more sustainable technologies. There is<br />
interest in developing <strong>the</strong>se technologies on one site, so that recycling, separation technologies<br />
or mechanical and biological treatment and anaerobic digestion is all integrated. NNFCC could<br />
examine <strong>the</strong> potential energy benefits in such trends and <strong>the</strong> impact <strong>the</strong>y may have on energy<br />
recovery from waste in general.
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Table 88 Recommendations for NNFCC’s role<br />
Challenge Purpose NNFCC<br />
1 Improve evidence base<br />
for policy and investment<br />
decision making<br />
2 Facilitate commercial<br />
transactions and develop<br />
SRF as a traded<br />
commodity.<br />
3 Improve quality of policy<br />
and investment decision<br />
making<br />
4<br />
5<br />
Provide an evidence base<br />
for <strong>the</strong> design and<br />
implementation of policy<br />
Build market confidence,<br />
enhance UK market<br />
share<br />
Quantifying arisings of C & I wastes. Reducing<br />
uncertainty in quantities, properties and composition<br />
of commercial and industrial waste streams. Data is<br />
very sparse compared with <strong>the</strong> municipal sec<strong>to</strong>r.<br />
Development of analysis methods in particular <strong>the</strong><br />
determination of <strong>the</strong> biogenic proportion of SRF<br />
Support <strong>the</strong> implementation of CEN standards for<br />
SRF<br />
Develop an understanding of <strong>the</strong> fit between SRF<br />
properties and energy production technologies.<br />
What properties does each of <strong>the</strong> technologies<br />
<br />
require?<br />
Develop a hierarchy of uses for each class of<br />
resource based on environmental and social <br />
benefits<br />
Develop an understanding of <strong>the</strong> relative timeframes<br />
of structural changes and technology developments <br />
necessary <strong>to</strong> maximise implementation.<br />
Develop a better understanding of <strong>the</strong> impacts of<br />
increased energy usage on alternative and existing <br />
markets for straw and o<strong>the</strong>r residues.<br />
Identify technology areas needing demonstration. <br />
Industrial pre qualification round for demonstration<br />
Implement a portfolio of shared cost technology<br />
demonstrations<br />
Lead<br />
Collaborate<br />
173<br />
O<strong>the</strong>rs lead<br />
<br />
<br />
<br />
<br />
<br />
1 – 2<br />
years<br />
2 – 5<br />
years<br />
5 – 10<br />
years<br />
Beyond<br />
10<br />
years
Appendices<br />
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Appendix 1: Fur<strong>the</strong>r information on Waste Arisings<br />
Appendix 2: Waste Legislation<br />
Appendix 3: MBT Methods
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Appendix 1<br />
Fur<strong>the</strong>r information on Waste Arisings<br />
This information has been provided so that methodologies for deriving <strong>the</strong> data can be followed, and reapplied, should information be required on a different<br />
scale.<br />
A1.1 Agricultural Residue Arisings<br />
The following tables give more detail regarding <strong>to</strong> potential Agricultural residue arisings and <strong>the</strong>ir energy content.<br />
Table 89 Lives<strong>to</strong>ck numbers for <strong>the</strong> UK, on a regional basis.<br />
East Midlands<br />
East of England<br />
North East<br />
North West<br />
South East inc.<br />
London<br />
South West<br />
West Midlands<br />
Yorkshire and<br />
Humber<br />
England – Total<br />
Nor<strong>the</strong>rn<br />
Ireland<br />
Dairy α<br />
O<strong>the</strong>r<br />
cattle β<br />
Cattle Pigs Poultry<br />
Calves γ Total Dry Sow δ<br />
Sows<br />
plus<br />
litter) ε<br />
Fattening<br />
pig (20-<br />
130kg) ζ<br />
175<br />
Weaners<br />
(
Scotland<br />
Wales<br />
UK – Total<br />
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170,820 1,176,390 549,970 1,897,180 41,420 6,230 285,210 123,900 456,760 2,920,240 1,586,610 8,308,280<br />
280,968 735,732 306,088 1,322,788 3,061 643 15,343 6,119 25,166 1,532,725 273,756 5,836,436<br />
2,242,212 5,059,471 3,138,339 10,440,022 459,711 75,549 3,043,345 1,249,063 4,827,668 34,270,836 9,771,642 1.5 x 10 8<br />
α Dairy cattle are dairy females over 2 years.<br />
β O<strong>the</strong>r cattle includes beef cattle, all males older than 1 year, and dairy females between 1-2 years<br />
γ Calves include all cattle younger than 1 year.<br />
δ Dry sows are pregnant pigs: sows in pig and gilts in pig, as well as boars for service and gilts.<br />
ε Sows plus litter are classified as ‘o<strong>the</strong>r sows’ in <strong>the</strong> census tables.<br />
ζ Fattening pig includes barren sows for fattening as well as all fattening pigs between 20 – 130 kg.<br />
Table 90 Volatile Solids of Collectable lives<strong>to</strong>ck manure arisings, for <strong>the</strong> UK, on a regional basis.<br />
Amounts are kilograms per day.<br />
East Midlands<br />
East of England<br />
North East<br />
North West<br />
South East inc.<br />
London<br />
South West<br />
West Midlands<br />
Yorkshire and<br />
Humber<br />
England – Total<br />
Nor<strong>the</strong>rn<br />
Ireland<br />
Scotland<br />
Dairy α<br />
O<strong>the</strong>r<br />
cattle β<br />
η All pigs under 20kg.<br />
θ Total layers includes growing pullets and laying birds.<br />
ι Includes layer breeders, broiler breeders, cocks and cockerels.<br />
κ Total fowls excludes all o<strong>the</strong>r types of poultry (turkeys, ducks, geese), as <strong>the</strong> numbers are considerable<br />
smaller, and a much greater proportion are free range.<br />
Cattle Pigs Fowls<br />
Calves γ Total Dry Sow δ<br />
Sows<br />
plus<br />
litter) ε<br />
Fattening<br />
pig (20-<br />
130kg) ζ<br />
Weaners<br />
(
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Wales<br />
380,743 996,999 0 1,377,742 675 304 2,233 436 3,648 81,234<br />
UK – Total<br />
3,038,448 6,856,150 0 9,894,598 101,366 35,697 442,898 89,033 668,994 1,816,354<br />
Table 91 Bio Methane Potential of collectable lives<strong>to</strong>ck manure arisings, for <strong>the</strong> UK, on a regional basis.<br />
Amounts are cubic meters (m 3 ) of methane per kilogram of Volatile Solids (VS).<br />
Cattle Pigs Fowls<br />
Dairy α O<strong>the</strong>r<br />
cattle β Calves γ Total Dry Sow δ<br />
Sows<br />
plus<br />
litter) ε<br />
Fattening<br />
pig (20-<br />
130kg) ζ<br />
Weaners<br />
(
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Table 92 Crop area potentially generating straw, <strong>by</strong> crop type and region of <strong>the</strong> UK 302<br />
Year<br />
Region Crop area<br />
(‘000 ha)<br />
2003 2004 2005 2006 2007 2008<br />
East Midlands Wheat 353 386 348 347 343<br />
O<strong>the</strong>r Cereals 104 90 82 82 84<br />
Oilseed rape 101 106 117 114 139<br />
East of England Wheat 481 513 486 472 470<br />
O<strong>the</strong>r Cereals 177 161 146 143 145<br />
Oilseed rape 94 91 101 104 130<br />
North East Wheat 66 71 68 65 66<br />
O<strong>the</strong>r Cereals 48 44 42 42 43<br />
Oilseed rape 22 25 25 23 27<br />
North West Wheat 28 36 31 31 30<br />
O<strong>the</strong>r Cereals 44 45 42 41 42<br />
Oilseed rape 4 4 4 4 4<br />
South East and Wheat 241 251 241 237 229<br />
London O<strong>the</strong>r Cereals 99 89 79 81 86<br />
Oilseed rape 75 81 83 79 92<br />
South West Wheat 174 191 180 176 172<br />
O<strong>the</strong>r Cereals 139 130 118 119 124<br />
Oilseed rape 41 48 47 45 52<br />
West Midlands Wheat 150 167 157 155 153<br />
O<strong>the</strong>r Cereals 80 70 64 65 69<br />
Oilseed rape 33 36 38 34 43<br />
Yorkshire and Wheat 233 252 237 227 227<br />
Humber O<strong>the</strong>r Cereals 126 116 108 107 111<br />
Oilseed rape 54 65 66 61 76<br />
England -Total 10379 10728 10182 9977 10343<br />
Scotland Wheat 88 101 96 100 103 114<br />
O<strong>the</strong>r Cereals 321 314 295 274. 279 320<br />
Oilseed rape 35 39 36 34 36 34<br />
Wales Wheat 15 15 15 16 -<br />
O<strong>the</strong>r Cereals 24 25 22 19 -<br />
Oilseed rape 3 3 3 3 -<br />
Nor<strong>the</strong>rn Wheat 7 9 8 9 9 12<br />
Ireland O<strong>the</strong>r Cereals 28 27 26 23 23 -<br />
Oilseed rape 0.1 0.3 0.3 0.5 0.4 -<br />
UK – Total 12197 12896 11935 11648<br />
302 Data collated from Defra Farm Survey 2008, Welsh Agricultural Statistics 2007,<br />
http://wales.gov.uk/docrepos/40368/4038231/statistics/agriculture/agric2008/was07/was07ch1.xls?lang=en , The Agricultural Census of Nor<strong>the</strong>rn<br />
Ireland and Statistical tables and graphs showing <strong>the</strong> final results of <strong>the</strong> 2008 June Agricultural and Horticultural Census, Scotland,<br />
http://www.scotland.gov.uk/News/Releases/2009/01/14164908.
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Table 93 Nutrient values of straw, taken from <strong>the</strong> ADAS Report for NNFCC. 303<br />
Nutrient value /t £/kg* Value £/t<br />
Wheat<br />
N - 5.0 kg 1.13 5.65<br />
P2O5 - 1.3 kg 1.45 1.89<br />
K2O - 9.3 kg 1.00 9.30<br />
Total 16.84<br />
Barley<br />
N - 6.0 kg 1.13 6.78<br />
P2O5 - 1.5 kg 1.45 2.18<br />
K2O – 12.6 kg 1.00 12.60<br />
Total 21.56<br />
Oilseed Rape<br />
N - 7.7 kg 1.13 8.70<br />
P2O5 - 2.2 kg 1.45 3.19<br />
K2O – 11.5 kg 1.00 11.50<br />
Total 23.39<br />
Table 94 Total Fowl Numbers raised on bedding, <strong>by</strong> region for <strong>the</strong> UK<br />
East Midlands<br />
East of England<br />
North East<br />
North West<br />
South East inc.<br />
London<br />
South West<br />
West Midlands<br />
Yorkshire and<br />
Humber<br />
England –<br />
Total<br />
Nor<strong>the</strong>rn<br />
Ireland<br />
Scotland<br />
Wales<br />
UK – Total<br />
Total Fowls<br />
Total<br />
Layers<br />
Fowls raised<br />
on bedding<br />
24,177,981 6,816,531 17,361,450<br />
25,312,303 2,458,942 22,853,361<br />
2,428,461 295,369 2,133,092<br />
8,262,834 2,453,187 5,809,647<br />
9,866,970 4,009,313 5,857,657<br />
18,315,773 5,952,707 12,363,066<br />
16,602,106 2,914,044 13,688,062<br />
14,408,052 2,519,278 11,888,774<br />
119,374,480 27,419,371 91,955,109<br />
16,321,500 2,398,500 13,923,000<br />
8,308,280 2,920,240 5,388,040<br />
5,836,436 1,532,725 4,303,711<br />
1.5 x 10 8<br />
34,270,836 115,729,164<br />
303 Addressing <strong>the</strong> land use issues for non-food crops in response <strong>to</strong> increasing fuel and energy generation opportunities, ADAS for NNFCC, 2008,<br />
http://www.nnfcc.co.uk/metadot/index.pl?id=8253;isa=DBRow;op=show;dbview_id=2539<br />
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Table 95 Estimated Poultry Litter output <strong>by</strong> Region<br />
180<br />
East Midlands<br />
East of England<br />
North East<br />
North West<br />
South East inc.<br />
London<br />
South West<br />
West Midlands<br />
Yorkshire and<br />
Humber<br />
England – Total<br />
Nor<strong>the</strong>rn<br />
Ireland<br />
Scotland<br />
Wales<br />
UK – Total<br />
Fowls raised on<br />
bedding<br />
Table 96 Estimated Poultry Litter output <strong>by</strong> Region<br />
East Midlands<br />
East of England<br />
North East<br />
North West<br />
South East inc.<br />
London<br />
South West<br />
West Midlands<br />
Yorkshire and<br />
Humber<br />
England – Total<br />
Nor<strong>the</strong>rn<br />
Ireland<br />
Scotland<br />
Wales<br />
UK – Total<br />
Litter output<br />
(‘000 <strong>to</strong>nnes)<br />
Energy Content<br />
(GJ)<br />
17,361,450 625 5,625,110<br />
22,853,361 823 7,404,489<br />
2,133,092 77 691,122<br />
5,809,647 209 1,882,326<br />
5,857,657 211 1,897,881<br />
12,363,066 445 4,005,633<br />
13,688,062 493 4,434,932<br />
11,888,774 428 3,851,963<br />
91,955,109 3,310 29,793,455<br />
13,923,000 501 411,052<br />
5,388,040 194 1,745,725<br />
4,303,711 155 1,394,402<br />
115,729,164 4,166 37,496,249<br />
Fowls raised on<br />
bedding<br />
Litter output<br />
(‘000 <strong>to</strong>nnes)<br />
Energy Content<br />
(GJ)<br />
17,361,450 625 5,625,110<br />
22,853,361 823 7,404,489<br />
2,133,092 77 691,122<br />
5,809,647 209 1,882,326<br />
5,857,657 211 1,897,881<br />
12,363,066 445 4,005,633<br />
13,688,062 493 4,434,932<br />
11,888,774 428 3,851,963<br />
91,955,109 3,310 29,793,455<br />
13,923,000 501 411,052<br />
5,388,040 194 1,745,725<br />
4,303,711 155 1,394,402<br />
115,729,164 4,166 37,496,249
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A1.2 Forestry Arisings<br />
The following table gives more detail regarding <strong>to</strong> potential Forestry residue arisings and <strong>the</strong>ir energy<br />
content, if no account of competing markets is made.<br />
Table 97 Current potential operationally available forestry residue resources <strong>by</strong> region (in <strong>the</strong> absence of<br />
competing markets)<br />
Region<br />
Forestry and Sawmill Co-<br />
Woodland (odt pa) product (odt pa)<br />
Arboricultural<br />
arising (odt pa)<br />
Total<br />
(odt pa)<br />
East Midlands 53,046 7,664 50,363 111,073<br />
East of England 70,489 24,577 37,357 132,423<br />
North East 82,956 50,615 11,133 144,704<br />
North West 86,063 37,899 25,979 149,941<br />
South East 94,994 22,191 119,160 236,345<br />
South West 125,633 27,204 27,012 179.849<br />
West Midlands<br />
Yorkshire and<br />
41,966 100,460 7,115 149,541<br />
Humberside 63,285 18,969 23,814 106,068<br />
Total England 618,432 289,579 301,933 1,209,944<br />
Scotland 848,345 403,538 12,448 1,251,883<br />
Wales 272,735 165,783 6,841 438,518<br />
Total Great Britain 2,919,634<br />
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1.3 Waste Wood Arisings<br />
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Table 98 Summary of <strong>the</strong> main <strong>report</strong>s that investigate arisings of waste wood from Construction and Demolition Activities.<br />
Source Data Quality Findings<br />
TRADA: wood residues – waste or<br />
resource? 1999 304<br />
Recycling of construction materials<br />
(IDE and NFDC), IDE, 1990 305<br />
Nottingham Trent University<br />
Study 306<br />
Environment Agency for England<br />
and Wales, Survey on wood waste<br />
from <strong>the</strong> Construction and<br />
Demolition sec<strong>to</strong>r 307<br />
Enviros’ Study of Nor<strong>the</strong>rn Ireland’s<br />
Construction and Demolition waste,<br />
2001 308<br />
• Construction waste data originates from BRE’s SmartWaste method:<br />
visual inspection of skip contents.<br />
• Data quality was judged as ‘very poor quality’, and containing<br />
considerable uncertainties. Therefore this data has not been used in<br />
subsequent discussions.<br />
• Demolition waste estimates rely on <strong>the</strong> compositional data ga<strong>the</strong>red<br />
through a desk data ga<strong>the</strong>ring exercise <strong>by</strong> <strong>the</strong> Institution of Demolition<br />
Engineers (IDE) in 1989. Total demolition waste also established from<br />
this survey.<br />
• Data quality was judged as ‘very poor quality’, and containing<br />
considerable uncertainties. Therefore this data has not been used in<br />
subsequent discussions.<br />
• The study measured <strong>the</strong> wood content of C&D waste stream <strong>to</strong>ge<strong>the</strong>r<br />
with waste from industries supplying construction products. Therefore it<br />
is not possible <strong>to</strong> know <strong>the</strong> composition of waste arising wholly from<br />
construction and demolition.<br />
• Composition established <strong>by</strong> manually sorting and weighing small skip<br />
contents in Nottingham in three successive years.<br />
• The quantities of waste sorted as part of this work were low, and <strong>the</strong><br />
data quality was assessed as having considerable uncertainties.<br />
• Considered C&D arisings for Wales in 2005-6.<br />
• Obtaining data was not straight forward as many companies did not<br />
keep records, or take an interest in responding <strong>to</strong> <strong>the</strong> survey.<br />
• Data is from a survey at <strong>the</strong> point of disposal of C&D wastes, and a<br />
survey based on point of arising.<br />
• Enviros indicated that this figure is probably an underestimate of <strong>the</strong><br />
true figure, since some wood would have been categorised as “o<strong>the</strong>r<br />
C&D wastes including mixed wastes.”<br />
• It should be noted that <strong>the</strong>re are a number of assumptions in <strong>the</strong><br />
estimates which could affect <strong>the</strong> quality of <strong>the</strong> estimation, but <strong>the</strong> data<br />
was assessed as being of reasonable quality.<br />
Woodwaste arisings in Scotland – • Taking <strong>the</strong> annual C&D <strong>to</strong>nnage of 6.28 million <strong>to</strong>nnes and assuming<br />
2% is waste wood.<br />
• Construction wood waste estimates were 25.77% and 19.3%.<br />
• Using <strong>the</strong> lower estimate of 19.3%, as a fraction of 10 million <strong>to</strong>nnes<br />
<strong>to</strong>tal UK construction waste arisings.<br />
⇒ Construction: 1,930,000 <strong>to</strong>nnes<br />
• Identified that 7% of demolition waste arisings were wood.<br />
• Multiplying this percentage <strong>by</strong> <strong>the</strong> <strong>to</strong>tal demolition waste of 25 million<br />
<strong>to</strong>nnes yields an arisings figure of:<br />
⇒ Demolition: 1,875,000 <strong>to</strong>nnes<br />
• An estimated average wood composition of 12.44% was identified.<br />
• As this value includes waste from <strong>the</strong> construction products industry, it<br />
is likely <strong>to</strong> be a high estimate.<br />
• Of <strong>the</strong> 12.2 million <strong>to</strong>nnes produced in this period, 3% of C&D waste<br />
was wood.<br />
⇒ 366,000 <strong>to</strong>nnes.<br />
• Identified waste wood <strong>to</strong> be 1.5% of construction and demolition waste,<br />
as a minimum figure.<br />
• Waste Watch - % of C&D waste that is wood is 2%<br />
⇒ 125,600 <strong>to</strong>nnes<br />
304<br />
This reflects TRADA’s comments on collection of wood waste information, Riddoch S TRADA: wood residues – waste or resource? 1999.<br />
305<br />
Recycling of construction materials – Joint survey <strong>by</strong> Institute of Demolition Engineers and National Federation of Demolition Contrac<strong>to</strong>rs (IDE and NFDC), IDE, 1990.<br />
306<br />
A comparative study of <strong>the</strong> quantities of construction waste arising in large and small skips in <strong>the</strong> Greater Nottingham area, Nottingham Trent University and APT for ShanksFirst Wastes Solutions and Nottingham City Council,<br />
2001.<br />
307<br />
A survey on <strong>the</strong> arising and management of construction and demolition waste in Wales 2005-06, Environment Agency, 2006, http://www.environment-agency.gov.uk/research/library/publications/33979.aspx<br />
308<br />
Construction and Demolition Waste Survey, Enviros Consulting Ltd for <strong>the</strong> Nor<strong>the</strong>rn Ireland Environment and Heritage Service (NIEHS), http://www.ni-<br />
environment.gov.uk/construction_and_demolition_waste_survey_nor<strong>the</strong>rn_ireland_2001.pdf.
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Remade Scotland, 2004. 309 • No explanation for <strong>the</strong> figure of 2%.<br />
BigREc Survey – A survey of <strong>the</strong><br />
UK reclamation and salvage trade<br />
2007 310<br />
Table 99 Estimates of industry specific waste wood arisings<br />
• Generated estimations of reclaimed and salvaged wood from a survey<br />
conducted in 1998, BigREc Survey, Salvo and BRE.<br />
• Data was ga<strong>the</strong>red from postal surveys with low response rate.<br />
• The methodology of how <strong>the</strong> responses were grossed up <strong>to</strong> a national<br />
figure is unclear, which makes it difficult <strong>to</strong> rate how reliable <strong>the</strong><br />
estimate is.<br />
• It is <strong>the</strong> only available data.<br />
• Total salvaged wood in <strong>the</strong> UK estimated <strong>to</strong> be 634,000 <strong>to</strong>nnes.<br />
C&I Industry Data Quality Waste Wood Arisings<br />
(<strong>to</strong>nnes)<br />
Furniture Manufacturing Sec<strong>to</strong>r 311 • Covers UK, 2000 – 2003<br />
530,511<br />
• Data quality is ei<strong>the</strong>r containing considerable uncertainties, or is poor.<br />
Manufacture of panelboards (MDF<br />
and chipboard only) 312<br />
• No estimate is made of how much of this waste is used for heat or power within <strong>the</strong> panel board<br />
industry or of <strong>the</strong> quality of <strong>the</strong> wood.<br />
1,107,074<br />
• Data covers <strong>the</strong> whole of UK, and is of ‘good quality’.<br />
Manufacture of wooden products for<br />
<strong>the</strong> construction industry 313<br />
• Figures can be broke down in<strong>to</strong>:<br />
• 181,522 <strong>to</strong>nnes (England and Wales),<br />
201,298<br />
• 17,991 (Scotland) and<br />
• 1,785 (Nor<strong>the</strong>rn Ireland)<br />
• Data contains considerable uncertainties or is of poor quality.<br />
Manufacture of wooden<br />
• Data covers <strong>the</strong> whole of <strong>the</strong> UK, and contains considerable uncertainties or is of poor quality. 40,000<br />
packaging 314<br />
Manufacture of o<strong>the</strong>r products of<br />
wood<br />
• EA waste production survey model run for Nikitas et al (2005) covering England and Wales 296,232<br />
Production of Railway Sleepers • From Nikitas et al (2005) own study.<br />
26,000<br />
• Data covers <strong>the</strong> whole of <strong>the</strong> UK and is of ‘good quality’.<br />
Utility poles • Data covers <strong>the</strong> whole of <strong>the</strong> UK.<br />
23,500<br />
• Several surveys performed, but few <strong>to</strong>ok account of regional density variations.<br />
• Nikitas et al corrected for this, and is believed <strong>to</strong> be <strong>the</strong> best estimate.<br />
Wood waste from ‘o<strong>the</strong>r’ C&I • Environment Agency’s waste production Survey, covering England and Wales. No information<br />
2,552,312<br />
arisings<br />
available for Scotland and Nor<strong>the</strong>rn Ireland.<br />
309 Woodwaste arisings in Scotland – assessment of available data on Scottish woodwaste arisings<br />
310 BigREc Survey, A survey of <strong>the</strong> UK reclamation and salvage trade, 2007, http://www.crwplatform.co.uk/conwaste/assets/Publications/BigREc<strong>full</strong><strong>report</strong>.pdf<br />
311 Furniture manufacture sec<strong>to</strong>r estimate is based on an average of three studies: Evaluation of waste production, utilisation, and brokerage potential within <strong>the</strong> UK furniture industry, FIET, 2002; Wood waste recycling in furniture<br />
manufacturing – a good practice guide, BFM, 2003; The use of microwave technology for <strong>the</strong> recovery of wood fibre from MDF, FIRA, 2004<br />
312 Determining <strong>the</strong> market share of recycled materials – Stage 2 case study <strong>report</strong>, Esys Consulting, 2004<br />
313 Environment Agency waste production survey 1998<br />
314 Based on “Trada- Turning a blind eye?” <strong>report</strong>, 2001<br />
183
184<br />
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• Calculated <strong>by</strong> subtracting figures from known industries sawmill wastes, wood products industry,<br />
furniture wastes) away from <strong>to</strong>tal arisings.<br />
• Likely <strong>to</strong> include waste wood from refurbishing industry – may be double counting with <strong>the</strong> C&D<br />
waste stream.<br />
• Likely <strong>to</strong> include a significant proportion of packaging waste.<br />
• Data is likely <strong>to</strong> be of ‘poor quality’ as based on visual inspections.<br />
Table 100 Estimations of future Waste wood arisings from various waste streams.<br />
Year<br />
MSW arisings<br />
(‘000 <strong>to</strong>nnes, no<br />
furniture)<br />
MSW furniture<br />
(‘000 <strong>to</strong>nnes)<br />
C&D<br />
(‘000 <strong>to</strong>nnes, mid<br />
range estimate)<br />
C&I<br />
(‘000 <strong>to</strong>nnes)<br />
2005 1,097 620 5091 6,563<br />
2006 1,113 629 5116 6,579<br />
2007 1,130 639 5142 6,595<br />
2008 1,147 648 5167 6,612<br />
2009 1,164 658 5193 6,628<br />
2010 1,181 668 5219 6,644<br />
2011 1,199 678 5245 6,661<br />
2012 1,217 688 5271 6,678<br />
2013 1,235 698 5298 6,695<br />
2014 1,254 709 5324 6,712<br />
2015 1,273 719 5351 6,729
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Appendix 2<br />
Waste Legislation<br />
Waste management strategies<br />
The European Union has become <strong>the</strong> major source of environmental legislation and guidance in<br />
relation <strong>to</strong> <strong>the</strong> management of waste. A number of European Directives which aim <strong>to</strong> increase levels<br />
of recycling and recovery, and thus reduce <strong>the</strong> amount of waste which is landfilled, have been<br />
introduced:<br />
• Framework Directive on Waste (75/442/EEC)<br />
• Landfill Directive (1999/31/EC)<br />
• Directive on Packaging and Packaging Waste (94/62/EEC)<br />
• Waste Electrical and Electronic Equipment Directive (2002/96/EC)<br />
• End of Life Vehicles Directive (2000/53/EC)<br />
• Ozone Depleting Substances (Regulation 2037/2000)<br />
• Directive on Batteries (2006/66/EC)<br />
• Waste Incineration Directive (2000/76/EC)<br />
Although most waste legislation in <strong>the</strong> UK has been introduced <strong>to</strong> meet <strong>the</strong> requirements set <strong>by</strong><br />
European Directives, <strong>the</strong> UK Government has also introduced additional legislation, some of which,<br />
such as <strong>the</strong> Landfill Tax Regulations 1996, is specifically aimed at encouraging recycling.<br />
Landfill Directive<br />
The European Commission Landfill Directive of 1999 (1999/31/EC) was passed in<strong>to</strong> English and<br />
Welsh law in 2002, and Scottish law in 2003. This aims <strong>to</strong> prevent, or minimise, <strong>the</strong> negative effects<br />
on both <strong>the</strong> environment and human health caused <strong>by</strong> landfilling of wastes. The Directive requires <strong>the</strong><br />
amount of biodegradable municipal solid waste (MSW) sent <strong>to</strong> landfill in <strong>the</strong> UK <strong>to</strong> be reduced:<br />
• <strong>to</strong> 75% of 1995 levels <strong>by</strong> 2010,<br />
• <strong>to</strong> 50% of 1995 levels <strong>by</strong> 2013, and<br />
• <strong>to</strong> 35% of 1995 levels <strong>by</strong> 2020.<br />
The Government has implemented <strong>the</strong> requirements for land filling of biodegradable waste through <strong>the</strong><br />
Waste and Emissions Trading Act 2003. This sets Waste Disposal Authorities annual allowances<br />
limiting how much biodegradable municipal waste (BMW) can be landfilled in any particular year, with<br />
effect from April 2005. The Government will fine Authorities that do not achieve <strong>the</strong>ir annual targets,<br />
but will allow Authorities <strong>to</strong> buy allowances from o<strong>the</strong>r Waste Disposal Authorities if <strong>the</strong>y expect <strong>to</strong><br />
landfill more than <strong>the</strong>ir allocations and sell <strong>the</strong>ir surplus if <strong>the</strong>y expect <strong>to</strong> landfill less than <strong>the</strong>ir<br />
allowance.<br />
The Landfill Directive also sets a requirement that only waste that has been subject <strong>to</strong> treatment can<br />
be landfilled. This requirement applied <strong>to</strong> landfilling of hazardous waste from July 2004, and was<br />
extended <strong>to</strong> all wastes (such as commercial and industrial wastes) destined for landfill (with some<br />
exceptions) from 30 Oc<strong>to</strong>ber 2007. A number of European countries have introduced 315 legislation<br />
which bans <strong>the</strong> landfilling of wastes with biological activity and intrinsic energy above set de-minimis<br />
limits. These restrictions apply <strong>to</strong> all wastes irrespective of <strong>the</strong>ir origin, and compliance is impossible<br />
without some form of treatment - mechanical, biological or <strong>the</strong>rmal. However, <strong>the</strong> guidance 316 for <strong>the</strong><br />
UK indicates that provided some source separation of recyclable material has occurred, <strong>the</strong> waste can<br />
be landfilled without requiring any fur<strong>the</strong>r treatment. The Government intends <strong>to</strong> consult on whe<strong>the</strong>r<br />
<strong>the</strong> introduction of fur<strong>the</strong>r restrictions on <strong>the</strong> landfilling of biodegradable wastes or recyclable materials<br />
would make an effective contribution <strong>to</strong> meeting <strong>the</strong> objectives (reducing greenhouse gas emissions<br />
315 Delivering Key Waste Management Infrastructure : Lessons Learned from Europe. Final Report <strong>by</strong> SLR <strong>to</strong> CIWM, November 2005<br />
316 Treatment of non-hazardous waste for landfill. Environment Agency, February 2007.
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and increasing resource efficiency) set out in <strong>the</strong> national waste strategy, but this would (due <strong>to</strong> <strong>the</strong><br />
need <strong>to</strong> construct <strong>the</strong> required treatment capacity) be a long term (at least 2020) target.<br />
National waste strategies<br />
An updated waste strategy for England 317 was published in May 2007. The aim of this updated Waste<br />
Strategy, which sets <strong>the</strong> Government’s vision for sustainable waste management, is <strong>to</strong> reduce waste<br />
<strong>by</strong> making products with fewer natural resources, and thus breaking <strong>the</strong> link between economic growth<br />
and waste growth. Products should be re-used, <strong>the</strong>ir materials recycled, energy from waste<br />
recovered, and landfilling of residual waste should occur only where necessary. The key points are:<br />
• Waste minimisation - A strong emphasis on waste prevention with householders reducing <strong>the</strong>ir<br />
waste (for example, through home composting and reducing food waste), business helping<br />
consumers, for example, with less packaging, development of a service which will enable<br />
households <strong>to</strong> opt-out of receiving un-addressed as well as addressed direct mail, and a<br />
reduction in <strong>the</strong> use of free single-use plastic bags.<br />
• Recycling - More effective incentives for individuals and businesses <strong>to</strong> recycle waste, leading<br />
<strong>to</strong> at least 40 per cent of household waste recycled or composted <strong>by</strong> 2010, rising <strong>to</strong> 45% <strong>by</strong><br />
2015 and 50 per cent <strong>by</strong> 2020. This is a significant increase on <strong>the</strong> targets (30% <strong>by</strong> 2010 and<br />
33% <strong>by</strong> 2015) in <strong>the</strong> previous waste strategy (which was published in 2000).<br />
• Treatment of residual waste - Increasing <strong>the</strong> amount of energy produced <strong>by</strong> a variety of<br />
energy from waste schemes, using waste that can't be reused or recycled. It is expected that<br />
from 2020 a quarter of municipal waste - waste collected <strong>by</strong> local authorities, mainly from<br />
households - will produce energy, compared <strong>to</strong> 10 per cent <strong>to</strong>day.<br />
The English waste strategy also included a new national target for <strong>the</strong> reduction of commercial and<br />
industrial waste going <strong>to</strong> landfill. This will require <strong>the</strong> level of commercial and industrial waste that is<br />
landfilled <strong>to</strong> fall <strong>by</strong> 20% <strong>by</strong> 2010 compared <strong>to</strong> <strong>the</strong> baseline of 2004.<br />
The Welsh Waste Strategy 318 , which was published in 2003, established a challenging but realistic<br />
programme of change <strong>by</strong> 2013. The aim of <strong>the</strong> strategy is <strong>to</strong> move Wales from an over-reliance on<br />
landfill <strong>to</strong> a position where it will be a model for sustainable waste management. This will be achieved<br />
<strong>by</strong> adopting and implementing a sustainable, integrated approach <strong>to</strong> waste production, management<br />
and regulation (including litter and flytipping) that minimises <strong>the</strong> production of waste and its impact on<br />
<strong>the</strong> environment, maximises <strong>the</strong> use of unavoidable waste as a resource, and minimises where<br />
practicable, <strong>the</strong> use of energy from waste and landfill.<br />
The Welsh strategy set <strong>the</strong> following targets:<br />
• Municipal solid waste<br />
o Each local authority <strong>to</strong> achieve a minimum 40% recycling/composting rate <strong>by</strong> 2009/10,<br />
with a minimum of 15% composting (with only compost derived from source<br />
segregated materials counting) and 15% recycling.<br />
o Waste arisings per household should be no greater than those (for Wales) in 1997/98<br />
<strong>by</strong> 2009/10.<br />
o By 2020, waste arisings per person should be less than 300kg per annum.<br />
• Commercial and industrial waste<br />
o Achieve, <strong>by</strong> 2010, a reduction in waste produced equivalent <strong>to</strong> at least 10% of <strong>the</strong><br />
1998 arisings figure.<br />
o Reduce, <strong>by</strong> 2010, <strong>the</strong> amount of industrial and commercial waste going <strong>to</strong> landfill <strong>to</strong><br />
less than 80% of that landfilled in 1998<br />
• C&D<br />
o To re-use or recycle at least 85% of C&D waste produced <strong>by</strong> 2010.<br />
317<br />
Waste Strategy for England 2007. Defra, May 2007.<br />
318<br />
Wise About Waste: The National Waste Strategy For Wales. Welsh Assembly Government, 2003.<br />
186 AEA
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The Scottish National Waste Plan of 2003 319 establishes <strong>the</strong> direction of <strong>the</strong> Scottish Executive’s<br />
policies for sustainable waste management <strong>to</strong> 2020. It is built around a major commitment of funding<br />
<strong>by</strong> <strong>the</strong> Executive <strong>to</strong> transform Scotland’s record on waste reduction, recycling, composting and<br />
recovery. It sets out challenging, but realistic objectives <strong>to</strong> achieve fundamental change in <strong>the</strong> way<br />
that Scotland’s waste is managed, and <strong>the</strong> main targets are <strong>to</strong>:<br />
• Achieve zero growth in <strong>the</strong> amount of municipal waste produced <strong>by</strong> 2010;<br />
• Achieve 55% recycling and composting of municipal waste <strong>by</strong> 2020 (35% recycling and<br />
20% composting);<br />
• Recover energy from 14% of municipal waste;<br />
• Reduce landfilling of municipal waste from around 90% <strong>to</strong> 30%;<br />
• Provide widesp<strong>read</strong> waste minimisation advice <strong>to</strong> businesses; and<br />
• Develop markets for recycled material <strong>to</strong> help recycling become viable and reduce costs.<br />
In 2007 Scotland also published a strategy for business 320 (C&I) waste. This aims <strong>to</strong> reduce <strong>the</strong><br />
amount of business waste which is landfilled through both reducing <strong>the</strong> amount of waste which is<br />
generated and increasing <strong>the</strong> recycling rate, but it does not set specific recycling targets.<br />
The Nor<strong>the</strong>rn Ireland waste strategy 321 , which was published in 2006, sets <strong>the</strong> following targets:<br />
• Recycling and Composting of Household Wastes <strong>to</strong> increase <strong>to</strong> 35% <strong>by</strong> 2010, and <strong>to</strong> 45%<br />
<strong>by</strong> 2020.<br />
• 60% of Commercial and Industrial Waste <strong>to</strong> be recycled <strong>by</strong> 2020<br />
• 75% of Construction, Demolition and Excavation Wastes <strong>to</strong> be recycled or reused <strong>by</strong><br />
2020.<br />
The national waste strategies all set targets for recycling/composting of MSW, and include<br />
requirements <strong>to</strong> meet <strong>the</strong> targets on landfilling of biodegradable MSW set <strong>by</strong> <strong>the</strong> landfill Directive. The<br />
targets for C&I waste aim <strong>to</strong> both reduce <strong>the</strong> amount of waste which is produced and reduce <strong>the</strong><br />
amount which is landfilled, but only <strong>the</strong> Nor<strong>the</strong>rn Ireland waste strategy sets a recycling target. Two<br />
strategies (Wales and Nor<strong>the</strong>rn Ireland) set recycling targets for C&D waste.<br />
English regional strategies<br />
Although some of <strong>the</strong> English Regions have published waste strategies, o<strong>the</strong>rs have covered waste<br />
within <strong>the</strong>ir spatial strategy/plan. Table 101 lists <strong>the</strong> waste reduction/minimisation, recovery and<br />
recycling targets set in each Region, and shows that only two regions (London and <strong>the</strong> South East)<br />
have set recycling targets for all (MSW, C&I and C&D) of <strong>the</strong> three main waste streams. Table 101<br />
also shows that some regions (such as <strong>the</strong> East of England) have set recovery targets but have not<br />
set recycling targets, and that only four regions have set waste reduction/minimisation targets.<br />
O<strong>the</strong>r targets/objectives included in <strong>the</strong> strategies/plans include:<br />
• London - Ensure that facilities with sufficient capacity <strong>to</strong> manage 75 per cent (15.8 million<br />
<strong>to</strong>nnes) of waste (MSW and C&I) arising within London are provided <strong>by</strong> 2010, rising <strong>to</strong> 80<br />
per cent (19.2 million <strong>to</strong>nnes) <strong>by</strong> 2015 and 85 per cent (20.6 million <strong>to</strong>nnes) <strong>by</strong> 2020<br />
• East Midlands - To reduce <strong>the</strong> amount of waste landfilled in accordance with <strong>the</strong> EU<br />
Landfill Directive, and take a flexible approach <strong>to</strong> o<strong>the</strong>r forms of waste recovery<br />
• East of England - The objective is <strong>to</strong> eliminate <strong>the</strong> landfilling of untreated municipal and<br />
commercial waste <strong>by</strong> 2021<br />
• West Midlands - The Region must play its part in delivering <strong>the</strong> targets set out in <strong>the</strong><br />
National Waste Strategy, and development plans should include proposals which will<br />
enable <strong>the</strong> Regional targets <strong>to</strong> be met.<br />
319 Waste Action Scotland: The National Waste Plan. Scottish Executive, 2003<br />
320 Business Waste Framework. Scottish Environmental Protection Agency (SEPA) and Scottish Executive, March 2007<br />
321 Towards Resource Management: The Nor<strong>the</strong>rn Ireland Waste Management Strategy 2006 – 2020. Nor<strong>the</strong>rn Ireland Department of<br />
Environment, 2006.
Table 101: Summary of targets in regional strategies<br />
Waste<br />
Recovery targets Recycling Targets<br />
minimisation/reduction<br />
Municipal Solid Commercial and Construction and<br />
Waste industrial waste demolition waste<br />
East of<br />
England 322<br />
- Municipal waste – recovery of 50%<br />
- - -<br />
<strong>by</strong> 2010 and 70% <strong>by</strong> 2015<br />
Commercial and industrial waste –<br />
recovery of 72% <strong>by</strong> 2010 and 75%<br />
<strong>by</strong> 2015<br />
East Midlands 323 To work <strong>to</strong>wards zero Overall recycling, recovery or re- To exceed<br />
- -<br />
growth in waste at <strong>the</strong> use rate for all waste streams of Government targets<br />
Regional level <strong>by</strong> 2016 75%<br />
for recycling and<br />
composting<br />
London 324 - - Exceed recycling or<br />
composting levels in<br />
municipal waste of:<br />
35 per cent <strong>by</strong> 2010<br />
45 per cent <strong>by</strong> 2015<br />
North East 325 - Municipal Solid Waste – <strong>to</strong> increase<br />
recovery <strong>to</strong> 53% <strong>by</strong> 2010 and 72%<br />
<strong>by</strong> 2016<br />
Commercial & Industrial – <strong>to</strong><br />
North West 326 Achieve and retain 0%<br />
growth in <strong>the</strong> amount of C&I<br />
wastes produced through<br />
<strong>the</strong> life of <strong>the</strong> Strategy,<br />
without compromising<br />
economic<br />
growth in <strong>the</strong> region<br />
increase recovery <strong>to</strong> 73% <strong>by</strong> 2016<br />
MSW - recover value from 67% of<br />
MSW <strong>by</strong> 2015<br />
recover value (including recycling)<br />
from at least 70% of all commercial<br />
and<br />
industrial wastes <strong>by</strong> 2020<br />
322 East of England Plan May 2008: The Revision <strong>to</strong> <strong>the</strong> Regional Spatial Strategy for <strong>the</strong> East of England. Government Office for <strong>the</strong> East of England, May 2008<br />
323 East Midlands Regional Waste Strategy. East Midlands Regional Assembly, January 2006.<br />
324 The London Plan: Spatial Development Strategy for Greater London. Greater London Authority, February 2008<br />
325 The North East of England Plan: Regional Spatial Strategy <strong>to</strong> 2021. Government Office for <strong>the</strong> North East, July 2008<br />
326 Regional Waste Strategy for <strong>the</strong> North West. North West Regional Assembly, September 2004<br />
Achieve recycling or<br />
composting levels in<br />
commercial<br />
and industrial waste<br />
of 70 per cent <strong>by</strong><br />
2020<br />
Achieve recycling<br />
and re-use levels in<br />
construction,<br />
excavation and<br />
demolition waste of<br />
95 per cent <strong>by</strong> 2020<br />
- - -<br />
- recycle 35% of all<br />
commercial and<br />
industrial wastes <strong>by</strong><br />
2020<br />
-
South East 327 - - 55% of MSW <strong>by</strong><br />
2020<br />
65% of C&I <strong>by</strong> 2020 60% of C&D <strong>by</strong> 2020<br />
South West 328 Become a minimum waste<br />
producer <strong>by</strong> 2030, with<br />
business and households<br />
maximising opportunities<br />
for reuse and recycling.<br />
- - - -<br />
West<br />
Midlands 329<br />
- Recover value from at least 45% of Recycle or compost<br />
- -<br />
municipal waste <strong>by</strong> 2005 and 67% at least 30% of<br />
<strong>by</strong> 2015;<br />
household waste <strong>by</strong><br />
Reduce <strong>the</strong> proportion of industrial 2010, and 33% <strong>by</strong><br />
and commercial waste which is<br />
disposed of <strong>to</strong> landfill <strong>to</strong> at <strong>the</strong> most<br />
85% of 1998 levels <strong>by</strong> 2005<br />
2015<br />
Yorkshire and<br />
Humber 330<br />
Moving <strong>the</strong> management of Achieving all statu<strong>to</strong>ry waste<br />
- - -<br />
all waste streams up <strong>the</strong> management performance targets<br />
waste hierarchy<br />
during <strong>the</strong> Plan period<br />
327 A Clear Vision for <strong>the</strong> South East – The South East Plan. South East England Regional Assembly (SEERA), March 2006<br />
328 From Rubbish <strong>to</strong> Resource: The Regional Waste Strategy for <strong>the</strong> South West 2004 – 2020. South West Regional Assembly, 2004<br />
329 Regional Spatial Strategy for <strong>the</strong> West Midlands. Government Office for <strong>the</strong> West Midlands, January 2008<br />
330 The Yorkshire and Humber Plan: Regional Spatial Strategy <strong>to</strong> 2026. Government Office for Yorkshire and <strong>the</strong> Humber, May 2008
The strategies consider future requirements for management of MSW; this is because of <strong>the</strong><br />
requirements for management of this stream in order <strong>to</strong> meet <strong>the</strong> targets for landfilling of MSW set in<br />
<strong>the</strong> Landfill Directive. However, only <strong>the</strong> London strategy sets requirements for treatment capacity for<br />
C&I waste, and whilst <strong>the</strong> London and South East strategies set high (over 60%) recycling targets for<br />
C&I waste, <strong>the</strong>se are unlikely <strong>to</strong> be achieved without future changes in Government policy.<br />
AEA
Appendix 3<br />
MBT Methods<br />
Specific in use processes for MBT include <strong>the</strong> 3R-UR process, illustrated below, with a typical mass<br />
balance for <strong>the</strong> system shown in Table 102, <strong>the</strong> BTA process, 331 and <strong>the</strong> Orchid Process.<br />
Table 102: Mass balance for 3R-UR process<br />
Figure 25: Flowsheet for <strong>the</strong> 3R-UR process 332<br />
Biogas<br />
Wt %<br />
3-5<br />
Recyclables and/or fuel product 15-20<br />
Compost product 15-20<br />
Process loss (waste gas – treated in biofilters before 40-45<br />
discharge <strong>to</strong> atmosphere)<br />
Residues (landfilled) 15-20<br />
Total 100<br />
331 Information at http://www.srm-norfolk.co.uk/index.htm<br />
332 Global Renewables, 3R-UR Process, http://www.globalrenewables.eu/ur3r-process
AEA<br />
Figure 26 Process flow sheet for <strong>the</strong> BTA process 333<br />
333 The BTA Process – Implementing Anaerobic Digestion in Wales Workshop 11 th November 2008, Enpure,<br />
http://www.swea.co.uk/downloads/Biogas_ROBYN.pdf
Figure 27 Orchid Environmental process 334<br />
334 Orchid – Seamless Waste Management Solutions, Company Brochure, http://www.orchidenvironmental.co.uk/downloads/pdf/orchid_process_4pp.pdf
AEA group<br />
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Tel: 0870 190 6036<br />
Fax: 0870 190 6318<br />
AEA