Renewable Energy Handbook 2010 - Department of Finance - The ...

50RENEWABLE ENERGY BACKGROUNDOFFICE OF ENERGYRENEWABLE ENERGY HANDBOOK 2010A 1.3 BioenergyA 1.3.3 TECHNOLOGIESBioenergy technologies are similar in that they relyon chemically complex and heterogeneous reactions,A 1.3.1 INTRODUCTIONand are versatile in that they can provide solid,liquid or gaseous fuels. These products can be usedOrganic matter, or bioenergy, can be converted intoas transport fuels or to generate electricity and heat.energy (heat and/or electricity) using a variety ofIn some cases, the technology may produce multipletechnologies. Bioenergy technology is a proven,products, such as charcoal, activated carbon, plantmature technology. The two main forms of bioenergyextracts, fertilisers, soil conditioners, as well asinclude the gasification of bioenergy (e.g. organic waste)energy products. Energy crops may also be usedunder anaerobic conditions to form biogas (includesto alleviate salinity problems, provide habitat forwaste-to-energy streams such as landfi ll) and thenative fauna, limit erosion, improve water qualitydirect combustion of bioenergy to generate energy.and improve nutrient cycling.The energy value of bioenergy originally comes from The basic bioenergy technologies available are:solar energy, through photosynthesis. The chemicalanaerobic digestion;energy that is stored in plants and animals, or inthe wastes they produce, is called bioenergy.direct combustion;During conversion processes such as combustion,pyrolysis;bioenergy releases its stored chemical energy.gasifi cation;Bioenergy can be used directly for electricityfermentation; andgeneration, steam for industrial uses, heating, cooking, transesterfi cation.or indirectly by converting it into a liquid or gaseous ·fuel (eg, ethanol from cellulose in woody bioenergy A 1.3.4 GENERATING HEAT AND POWERor starch/sugar crops or biogas from animal waste). Products created in the above technologies in theBioenergy-based generators have the advantage of form of biogas, producer gas, syngas, ethanol andnot being dependant on weather conditions and can biodiesel can be converted to thermal energy bydeliver output at specifi c times of demand, providing combustion. Electrical energy is achieved by conversionmaximum fi nancial return, due to the inherent of the thermal energy via a number of different methods.energy storage in bioenergy.The current technologies capable of converting theseproducts into useable forms of energy include:A 1.3.2 BIOENERGY RESOURCESreciprocating gas engines;There are many types of bioenergy that can be utilised gas turbines;as a resource for renewable energy. These resourcesboiler and steam turbines;can be grouped under the following broad headings:Stirling engine; andEnergy crops – e.g. fast growing agricultural crops· fuel cells (potentially).and forestry species;·Agricultural crop residues – e.g. straw,A 1.3.5 CURRENT APPLICATIONS·husks and stubble;In 2007, less than one per cent of Australia’s totalForestry residues – e.g. sawmill andenergy supply was generated using bioenergy.·plantation residues;In comparison, the USA generates 40 terawattAnimal wastes – e.g. manure and abattoir wastes; hours of electricity. This is equivalent to the entireIndustrial wastes – e.g. fruit and vegetable scraps grid-connected electricity demands of Western·and processing wastes;Australia, South Australia and Tasmania combined.Bioenergy contributes 14 per cent of Finland’sMunicipal solid (green); and· Waste sewage. energy needs, 6 per cent in Denmark and delivers5 per cent in Sweden.Mallee has the potential to be a large-scale salinitycontrol crop and source of bioenergy for industrialproducts and electricity generation. There is alsosignifi cant potential to generate energy from plantationharvest residue in Western Australia. The applicationsof bioenergy can be categorised for use as transportfuels, heating, cooling or electricity generation.75963- 0