In principle, biofuels are climate-neutral, as the carbon is absorbed by the plants while growing and then released when the fuel is used. However, the current approach to biofuels is driven by politics and energy security – the desire to reduce oil imports – not climate policy. The main biofuel, ethanol, if taken from intensively-farmed corn and produced using coal-based electricity, damages the climate even more than oil does. In addition, using large areas of agricultural land (for example, 8% of US agricultural land is now growing corn for ethanol) means that food has to be grown elsewhere, often adding to deforestation. If these ‘indirect effects’ are taken into account – as they should be – many current biofuels are much more climate-damaging than oil. However, ethanol made from sugar cane, as it is in Brazil, has a positive impact on the climate (see Worldwatch Insititute: Vision for a Sustainable World).
We are promised that the direct and indirect disadvantages of biofuels will be removed by ‘second-generation biofuels’ and the advantages will be further increased by ‘third generation biofuels’.
Main current biofuel production
Corn-based US ethanol and sugar cane-based Brazilian ethanol account for nearly 90% of global biofuel production, with each producing around 4.4 billion gallons. Ethanol production more than doubled between 2000 and 2005, but is still only about 1.5% of global fuel use. In 2008, over 27 million acres of corn were planted for ethanol in the US, 8% of the total US agricultural land. The biofuel produced replaced 6% of oil used for transport. China is the third largest producer of ethanol (from corn and maize), but only produces about an eighth of the two largest producers.
Biodiesel production from vegetable oils, derived from rapeseed, soy beans, palm oil and other crops, quadrupled between 200 and 2005, though this started from a smaller base (see Earth Policy Institute, 2006). Germany is the largest producer of biodiesel, producing 500 million gallons from rapeseed in 2007. France is next (135 million gallons from soy), then the US (77 million gallons from rapeseed).
Palm oil, which can also be used to produce biofuel, has replaced soybean as the world’s most traded oilseed crop. In 2006, 85% of the global palm-oil crop was produced in Indonesia and Malaysia.
Southern African countries are increasingly growing jatropha, a drought-resistant plant that requires little or no input of pesticides or fertilisers. Its beans can be harvested three times a year and the by-products can be used to make soap and medicine. They are turned into biofuel in South Africa.
Climate impacts of current biofuels
These are highly contested, so impartial information is hard to find.
In December 2007, researchers at Colorado State University’s Natural Resource Ecology Laboratory (NREL) and the US Department of Agriculture published an analysis which concluded that, when compared with the lifecycle of petroleum, ethanol from corn and biodiesel from soybean reduced greenhouse gas emission by nearly 40%. However, this included only direct emissions, from soil nitrous oxide emissions and the CO2 emissions from farm machinery, and not indirect effects such as deforestation (see Colorado State University: CSU anbd USDA scientists find significant greenhouse gas reductions associated with biocrop fuel systems).
Berkeley professor, Daniel Kammen published a report in 2008 warning that on a ‘well-to-wheel’ basis (that is, taking account of all direct and indirect emissions from the entire process), a car emits more greenhouse gases driving on corn ethanol processed with coal than it does using normal petrol. The main impact was due to so much US land being used to grow corn for ethanol, so driving soya production to Brazil and causing Amazon destruction (see Renewable and Appropriate Energy Laboratory: Obama’s biofuel policy tension).
Making ethanol from sugar cane, as the Brazilians do, or from municipal and farm waste, has a much more favourable energy balance. Much of the energy required for distillation and processing can be supplied by burning the non-carbohydrate parts of the feedstock (which are not required for ethanol conversion). This is done in highly efficient combined heat and power plants, which run the distilleries and dramatically increase the net energy balance. The Worldwatch Institute says that ethanol from sugar cane has an approximately 80% climate benefit.
Around two-thirds of the emissions resulting from biodiesel made from rapeseed – the main feedstock for biodiesel in the EU – occur during farming of the crop, when cropland emits nitrous oxide. (This is 200 to 300 times as potent a greenhouse gas as CO2.) An April 2007 study claimed that the use of rapeseed-derived biodiesel could result in greater emissions of greenhouse gases than from conventional oil-derived diesel. However, the report was by SRI Consulting, a group which works mainly for the petrochemical industry. Independent academics have shown better greenhouse gas balances for rapeseed-based biodiesel. In fact, the SRI study does not take into account the greenhouse gas emissions that are avoided because of the use of biodiesel by-products as animal feed or as a fuel feedstock. The major by-product of biodiesel is a chemical compound that can be used for the production of further renewable fuels such as biogas. However, growing rape seed on European farms clearly has indirect effects too.
Palm oil has a direct effect of deforestation. About 85% of the global palm oil is produced by Indonesia and Malaysia, countries whose combined annual tropical forest loss is around 20,000 square kilometres. 99% of the palm oil is used for things other than biofuel – notably in prepared meals – and only 1% for biofuels. However, this does not mean that cutting down forests to produce palm oil as a biofuel makes any sense.
So far, there has been no lifecycle analysis of jatropha biofuel, but it was reported in 2008 that producing a single litre of biodiesel from jatropha requires 20,000 litres of water (PNAS: The water footprint of bioenergy). And non-governmental organisations in Swaziland are saying that agricultural land, which could and should be used to grow food, is being used instead to grow jatropha (see Friends of the Earth 2009: Jatropha wonder crop? Experience from Swaziland).
Second generation biofuels
‘Second-generation’ biofuels will come from wood, grasses, municipal and farm waste (including corn stalks) or specially grown non-food crops (including switchgrass). Industry sources claim that these could reduce emissions by as much as 90%, but this does not include the indirect effects these crops would inevitably give rise to.
Attempts to produce second-generation ethanol have been made for more than 20 years. However, the biochemistry of this approach is more complex and, therefore, more expensive than producing ethanol from corn, which basically uses the same brewing and distilling techniques as producing beer and spirits. Therefore, these biofuels are not yet commercially available.
There is also talk of third generation biofuel from algae. Algae are low-input and high-yield. It is claimed that using algae as the feedstock could produce 30 times more energy per acre than land crops such as soybeans. The US Department of Energy says that if algae fuel replaced all the petroleum fuel in the US, it would require only 15,000 square miles, which is roughly the size of Maryland!
What can biofuels be used for?
The answer is rather simple – essentially, anything that oil is now used for. Vehicle manufacturers were initially cautious, but aren’t any longer. Aircraft manufacturers and airlines were even more cautious, but there was a test flight in 2007 by a Czech Aircraft completely powered on biofuel and a partially-biofuelled commercial aircraft flew from London to Amsterdam (though without passengers) in February 2008.