Biofuels are liquid fuels of biological origin that have not been fossilised. Biodiesel and ethanol are two commonly used biofuels which can be blended with conventional fuels and used in existing drive train technologies.
Biodiesel is typically made from vegetable oils, animal fats and used cooking oil. It can also be produced from various non-food crops such as Pongamia and algae, although the use of these feedstocks to make biodiesel is currently at a research, development and/or pre-commercialisation demonstration stage.
Biodiesel can be blended with conventional diesel fuel or used as a neat fuel (100 per cent biodiesel). It is typically used as a fuel additive in five per cent (B5) and 20 (B20) per cent biodiesel-diesel blends.
Biodiesel and diesel can differ slightly in terms of energy content, cetane number (analogous to gasoline’s octane rating in terms of engine performance) or other physical properties.
Biodiesel is biodegradable, requires minimal engine modification when used either in a blend or neat, and is cleaner burning than the diesel it replaces.
There are currently four biodiesel producers in Australia which include: Biodiesel Producers Ltd (Victoria), Smorgon Fuels Pty Ltd (Victoria), Biodiesel Industries Australia (New South Wales), and Australian Renewable Fuels Ltd (Western Australia and South Australia)
Ethanol is an alcohol, produced from various sugars through fermentation and distillation.
The process is similar to brewing beer, where starch crops are converted into sugars and then into alcohol. Australia's ethanol is currently produced from wheat, sorghum and C grade molasses. Although it is possible to produce ethanol from biomass and urban waste, such processes are yet to be fully commercialised.
Ethanol is typically used as a fuel extender and to increase octane levels in petrol. In Australia, ethanol is most commonly sold as E10—which is a blend of up to 10 per cent ethanol and at least 90 per cent petrol. There are currently three ethanol production plants in Australia, which are Manildra (Nowra, New South Wales), Sucrogen (Sarina, Queensland) and the Dalby Biorefinery (Dalby, Queensland).
Under certain circumstances, ethanol can achieve environmental benefits. The use of E10 in place of unblended petrol reduces the emissions of certain pollutants from the vehicle exhaust. Ethanol as a transport fuel may also realise a greenhouse benefit when it is produced from a waste product (for example, C-grade molasses) or the energy source used in its production is relatively clean (for example, co-generation).
For more information about biofuels email TransportFuels@ret.gov.au.