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Evaluation of Opportunities for Converting Indigenous UK Wastes to Wastes and Energy
AEA/ED45551/Issue 1
significant saving is if the biogas is used for CHP and highly efficient use of the heat generated is
achieved.
11.2 Scenario 2: Wood Waste
Wood waste is taken here to be wood that is contaminated, either impregnated with preservatives, or
coated with paints and varnished. Disposal therefore requires WID compliant facilities, and currently only
the largest of facilities have appropriate emissions cleaning facilities. While a considerable quantity of
such material is estimated to be disposed of each year, there is little good quality data for this waste
stream. Estimations from WRAP put the volume of wood waste at 1,065,000 tonnes from MSW, 602,000
tonnes from waste furniture, 4,400,000 tonnes from C&D waste (5,040,000 if include reclaimed wood),
and 4,481,000 tonnes from C&I waste. This would potentially offer 10,548,000 tonnes of wood waste a
year.
The options available for the disposal of wood waste are for it to be sent to landfill or for it to be
segregated and used as a feedstock for combustion, generating heat, CHP or electricity. An alternative
possibility is for a conversion process to be used, such as gasification followed by Fischer Tropsch to
generate a transport fuel. This however hasn’t been modelled as we have been unable to identify
sufficient data on using wood waste as a feedstock for this process.
Waste Wood
Combustion
Landfill
With landfill gas
Heat, CHP
or Electricity
Figure 24 Disposal options for waste wood
It is assumed that most wood waste is disposed of to landfill with energy recovery. Such a scenario has
not been taken as the reference system for this work as the intention here is to compare the different end
uses of waste wood, and comparison to landfilling can generates large negatives that do not allow
accurate comparison. In the following situations the GHG savings come from the displaced fossil fuel, in
each case natural gas, so once again giving a conservative estimate of the savings generated.
Two different scenarios considering the GHG saving that could be achieved from using waste wood as a
feedstock for energy generation.
1. Industrial or commercial building heating. This system is already economic, but still has
challenges to face including WID compliant facilities, fuel storage and ash disposal.
2. Combustion in a medium scale plant – the practical limit for waste levels generated within an
RDA geographical region. Such a system would be economic with the currently available
subsidy i.e. the availability of 1.5 ROC.
Both systems have been considered in terms of the displacement of natural gas as the fossil fuel
equivalent and are estimated to would produce the following GHG savings: