Biofuels are currently produced from starch, sugar and oil feedstocks that include wheat, maize, sugar cane, palm oil and oilseed rape. The best-known example of their use comes from Brazil where since the 1970s large plantations of sugar cane have produced ethanol for use as a fuel mainly in transport, generating, incidentally, much less local pollution than petrol or diesel fuel from fossil sources. Residues from ethanol or sugar production are used to generate electricity to power the factories and to export to the grid, ensuring good efficiency for the total process both in terms of energy and of saving carbon emissions.

Decisions about the large-scale production of biofuels must be guided by thorough and comprehensive assessments that address their overall efficiency and overall contribution to the reduction of carbon emissions.44 Also requiring careful assessment is the degree to which their use of land is competing with food crops (as for instance with the use of maize) or adding to deforestation of tropical forests (as for instance with some palm oil plantations) that itself contributes substantially to greenhouse gas emissions. Examples have recently come to light of adverse consequences (for instance on world food prices) arising from a lack of adequate assessment.

Energy is also available in cellulosic biomass - as is evident from a cattle's rumen which turns grass into energy. On a laboratory scale, this process can be replicated and biofuels produced from lignocellulose from grasses or woody material or from the residue from cereal or other crops. A strong focus of recent work is turning this into commercial large-scale production of biofuels especially from woody wastes or from grasses such as Miscanthus grown on marginal land where it is not competing with food crops. Already this is beginning to happen and the scenarios I have presented assume that these second-generation biofuels, as they are called, can be successfully developed on the scale required.45

Figure 11.14 Miscanthus and willow growing at the Institute for Grassland and Environmental Research (IGER), Aberystwyth University,UK.
Guide to Alternative Fuels

Guide to Alternative Fuels

Your Alternative Fuel Solution for Saving Money, Reducing Oil Dependency, and Helping the Planet. Ethanol is an alternative to gasoline. The use of ethanol has been demonstrated to reduce greenhouse emissions slightly as compared to gasoline. Through this ebook, you are going to learn what you will need to know why choosing an alternative fuel may benefit you and your future.

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