114- www. world- petroleum. org 6.7- Understanding oil and gas Biofuels: explained With the world's largest economies pushing increased usage, biofuels are here to stay The internal combustion engine is a part of virtually everybody's life - like it or not, it's here for the foreseeable future ( see p20). But we need to cut down on the amount of harmful carbon emissions it produces. That's where biofuels come in: they offer the prospect of reductions in carbon emis-sions without the need to replace or radi-cally alter existing transportation infrastruc-ture. Hydrogen and electricity are interest-ing alternatives for powering vehicles, but they require a complete redesign of the way vehicles work and can't be used with exist-ing cars, whereas biofuels can. Biofuels are created by processing veg-etation high in sugars or vegetable oil into bioethanol and biodiesel. These can be blended with, or even used instead of, con-ventional gasoline and diesel - and they produce much less pollution when burned than conventional refinery fuels. In the EU, one of the world's biggest vehi-cle markets, nations are being asked to raise the amount of renewable energy - mainly biofuels - used for transport to 10% of total fuel consumption by 2020, compared with an average of well under 5% now. That's a significant increase. Similar measures are being implemented, or targeted, around the world; this will require billions of dollars in financial incentives, but proponents believe the environmental benefits will be worth all the effort and money. The biofuels industry is already well es-tablished in the major economies. The US, the world's biggest biofuels manufacturer, produces bioethanol from maize ( known lo-cally as corn) cultivated across the Midwest. Germany produces biodiesel from rape-seed, among other feedstocks. Brazil, the world's biggest ethanol exporter, pioneered the production of ethanol from sugar cane, taking full advantage of its ample land re-sources and sub- tropical climate; it has also developed flexible- use, or flex- fuel, cars that can run on any ratio of gasoline and biofu-els. China, India and other fast- developing economies in the Asia- Pacific region are also turning to biofuels as part of their ef-forts to find viable new transport fuels. According to the US Department of Energy, total annual biofuels production across the world could increase more than sixfold by 2030, from 12 billion US gallons in 2005 to 83 billion US gallons in two decades' time. Fuelling change? Exactly what form biofuels in use in a dec-ade's time will take remains to be seen, but a big change seems to be in the offing. The main biofuels on the market today - so-called first- generation biofuels - are bioeth-anol and biodiesel, which can be made from a variety of raw materials, but are generally derived from crops such as maize, sugar cane, palm oil and rapeseed. However, there are doubts over whether they make a positive contribution to the environment: in Biofuels are created by processing veg-etation high in sugars or vegetable oil

115- www. energy- future. com 6.7- Understanding oil and gas some cases, carbon savings made by burn-ing clean biofuels in motor vehicles can be outweighed by the carbon dioxide ( CO2) that is emitted during the cultivation of the crops, their conversion into fuels and their trans-portation to market. Biofuels present another significant risk: by occupying land that could be used to grow food crops, the cultivation of crops for fuels could lead to food shortages and infla-tion in food prices. However, the commercialisation of sec-ond- generation biofuels technologies - bi-omass- to- liquids and cellulosic ethanol, for example - could assuage many of these worries. These emerging technologies en-able biofuels to be manufactured from a much wider range of raw materials, includ-ing agricultural by- products, such as plant husks and inedible maize stalk and grasses, which are easy to grow and can't be eaten. Even algae can be used to produce biofuels ( see p78). This should improve production efficiency and reduce carbon emissions per unit burned. It also ought to ease compe-tition with the food industry because some second- generation biofuels crops can be grown on marginal land that is unsuitable for cultivating food crops. Much scientific work remains to be done to perfect these technologies, but the backing they are receiving in high places suggests they have a bright future. The US already requires a minimum amount of bioethanol to be blended into gasoline and has set a tar-get of using 36 billion US gallons of biofuel a year by 2022. And, in May 2009, US pres-ident Barack Obama's government upped the ante, with plans to spend $ 1.8 billion on developing second- generation biofuels. Biofuels: key concepts Bioethanol: also known simply as ethanol ( ethyl alcohol), this is the most widely pro-duced biofuel. It is usually created by fer-menting starch or sugar crops, including maize ( corn), sugar beet and sugar cane. Bioethanol is often blended with gasoline to fuel cars. In some cases, it can com-pletely replace gasoline as a fuel. Biodiesel: a combustible fuel that can be mixed with mineral diesel. Derived from fatty- acid alkyl esters, biodiesel can be made from a wide variety of feedstocks, such as rapeseed and soybean oils. Biomass: in the context of the fuel sector, any vegetation whose energy can be har-nessed in fuel. Biomass- to- liquids ( BTL): a combustion, rather than fermentation, process, in which biomass is converted into synthesised gas, or syngas, and then put through re-actions with other compounds to produce a variety of end- products, including diesel and ethanol. BTL products are made us-ing Fischer- Tropsch technology, which has been developed in another area of the en-ergy industry, the gas- to- liquids sector. Cellulosic fermentation: most fermenta-tion processes could be called cellulosic, as the word just refers to breaking down lignocellulose in plant matter. However, in the biofuels industry, it normally signifies the ability to break down a much greater amount of plant matter than has been possible on a commercial scale to date. The end result is the same, though - bioethanol, for example. Jatropha: a plant indigenous to Central America that produces oil suitable for conversion to biodiesel. It has attracted much interest because it grows well on marginal land across tropical and sub-tropical areas, in places such as India and Africa. This reduces the pressure on land needed for food crops, although it remains to be seem whether jatropha's much- touted potential can be converted into commercial success. Emerging second- generation technologies enable biofuels to be manufactured from a much wider range of raw materials