Biofuels
Easily the largest and possibly the most controversial of the alternative fuels available today, biofuels have seen explosive global growth over the last decade as fuel prices rise and consumers become increasingly aware of the effect that their everyday activities may have on the environment.
Biofuels are any type of liquid or gaseous fuel that is derived from an organic, renewable source. The most popular example of this is ethanol, which is largely derived from corn or sugar cane. Other fuels include biodiesel, biobutanol and other organic fuels.
The process for extracting useful product from these organic materials varies widely between fuel types and material used, as does their effectiveness and efficiency.
The Federal government has set a target of 350 million litres of biofuels produced annually by 2010.
Ethanol
Ethanol is the most common biofuel in Australia, with an estimated 23 million litres produced in the 2004-05 year. It is generally combined with petrol in a 10/90 blend, commonly sold as “E10″ fuel. E10 is certified for use in 60 per cent of Australian vehicles (of which most are post-1986 models).
Ethanol is the most common biofuel in Australia, with an estimated 23 million litres produced in the 2004-05 year. It is generally combined with petrol in a 10/90 blend, commonly sold as “E10″ fuel. E10 is certified for use in 60 per cent of Australian vehicles (of which most are post-1986 models).
Ethanol has a lower energy content than unleaded petrol (about 34% lower by volume), resulting in higher fuel consumption depending on the ethanol concentration. However it also has a higher octane number which is comparable to premium unleaded petrol.
In Australia, ethanol is mostly produced from molasses (a sugar cane byproduct). For each unit of fossil fuel used to create sugar cane ethanol, eight units of ethanol can be produced.
In recent years there were incidents where unmarked high-ethanol content fuels were used in vehicles that were not equipped for them, allegedly causing damage. Although a review and enforcement of ethanol classification standards can help resolve this, it will take time for consumer confidence to be fully restored.
Biodiesel
Biodiesel varies slightly from ethanol in that it can be produced not only from crops (primarily canola and soybean in Australia), but also from animal fat or cooking oil. Its energy content is comparable to that of mineral diesel (around 90 per cent), and use in diesel-powered vehicles requires no modifications, though some manufacturers will not endorse using pure biodiesel in their engines. Approximately 4 million litres of biodiesel was produced in the 2004-05 year.
Biodiesel varies slightly from ethanol in that it can be produced not only from crops (primarily canola and soybean in Australia), but also from animal fat or cooking oil. Its energy content is comparable to that of mineral diesel (around 90 per cent), and use in diesel-powered vehicles requires no modifications, though some manufacturers will not endorse using pure biodiesel in their engines. Approximately 4 million litres of biodiesel was produced in the 2004-05 year.
Biodiesel is available at selected retail outlets in many parts of Australia, where it is generally sold as “B20″ (that is 80% diesel + 20% biodiesel). As with ethanol, biodiesel is claimed to offer significant greenhouse gas emission reductions over its fossil fuel equivalents, though this is now being challenged by more rigorous life-cycle analysis that include detailed examination of the nitrogen cycle (N2O emissions are 296 times more greenhouse intensive than CO2).
Biodiesel still suffers some minor technical problems such as difficulty working at sub-zero temperatures. Blending with mineral diesel, such as in B20, assists in alleviating these problems.
Competition with food crops
Significant production of biofuels from farm crops is now competing for the use of arable land and food prices are starting to be seriously impacted. The cost of corn, wheat, maize, and soy has skyrocketed.
Significant production of biofuels from farm crops is now competing for the use of arable land and food prices are starting to be seriously impacted. The cost of corn, wheat, maize, and soy has skyrocketed.
Clearing rainforest
Indonesian rainforest is now being cleared to grow palm oil for biofuel. Apart from the loss of habitat and bio-diversity this releases huge amounts of carbon that was stored in the forest – far more than will ever be saved by burning palm oil in our cars. So it is clear that serious international regulation is necessary, underpinned by rigorous full life-cycle greenhouse impact assessment.
Indonesian rainforest is now being cleared to grow palm oil for biofuel. Apart from the loss of habitat and bio-diversity this releases huge amounts of carbon that was stored in the forest – far more than will ever be saved by burning palm oil in our cars. So it is clear that serious international regulation is necessary, underpinned by rigorous full life-cycle greenhouse impact assessment.
Next generation biofuels
Upcoming technologies, such as cellulosic ethanol and algae biodiesel look promising and may eliminate the need to use food crops entirely, but they are not expected to be put into widespread use for a number of years.
Upcoming technologies, such as cellulosic ethanol and algae biodiesel look promising and may eliminate the need to use food crops entirely, but they are not expected to be put into widespread use for a number of years.
