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Biofuels, in the form of liquid fuels derived from plant materials, are entering the market, driven by factors such as oil price spikes and the need for increased energy security. However, many of the biofuels that are currently being supplied have been criticised for their adverse impacts on the natural environment, food security, and land use.〔〔 The challenge is to support biofuel development, including the development of new cellulosic technologies, with responsible policies and economic instruments to help ensure that biofuel commercialization is sustainable. Responsible commercialization of biofuels represents an opportunity to enhance sustainable economic prospects in Africa, Latin America and Asia.〔The Royal Society (January 2008). ''Sustainable biofuels: prospects and challenges'', ISBN 978-0-85403-662-2, p. 61.〕〔Gordon Quaiattini. (Biofuels are part of the solution ) ''Canada.com'', April 25, 2008. Retrieved December 23, 2009.〕〔EPFL Energy Center (c2007). ''(Roundtable on Sustainable Biofuels )'' Retrieved December 23, 2009.〕 Biofuels have a limited ability to replace fossil fuels and should not be regarded as a ‘silver bullet’ to deal with transport emissions. However, they offer the prospect of increased market competition and oil price moderation. A healthy supply of alternative energy sources will help to combat gasoline price spikes and reduce dependency on fossil fuels, especially in the transport sector.〔 Using transportation fuels more efficiently is also an integral part of a sustainable transport strategy. ==Biofuel options== Biofuel development and use is a complex issue because there are many biofuel options which are available. Biofuels, such as ethanol and biodiesel, are currently produced from the products of conventional food crops such as the starch, sugar and oil feedstocks from crops that include wheat, maize, sugar cane, palm oil and oilseed rape. Some researchers fear that a major switch to biofuels from such crops would create a direct competition with their use for food and animal feed, and claim that in some parts of the world the economic consequences are already visible, other researchers look at the land available and the enormous areas of idle and abandoned land and claim that there is room for a large proportion of biofuel also from conventional crops.〔The Royal Society (2008). p. 2.〕 Second generation biofuels are now being produced from a much broader range of feedstocks including the cellulose in dedicated energy crops (perennial grasses such as switchgrass and Miscanthus giganteus), forestry materials, the co-products from food production, and domestic vegetable waste. Advances in the conversion processes〔Catherine Brahic. (Hydrogen injection could boost biofuel production ) ''New Scientist'', March 12, 2007. Retrieved December 23, 2009.〕 will improve the sustainability of biofuels, through better efficiencies and reduced environmental impact of producing biofuels, from both existing food crops and from cellulosic sources.〔The Royal Society (2008). p. 2 & 11.〕 In 2007, Ronald Oxburgh suggested in ''The Courier-Mail'' that production of biofuels could be either responsible or irresponsible and had several trade-offs: "Produced responsibly they are a sustainable energy source that need not divert any land from growing food nor damage the environment; they can also help solve the problems of the waste generated by Western society; and they can create jobs for the poor where previously were none. Produced irresponsibly, they at best offer no climate benefit and, at worst, have detrimental social and environmental consequences. In other words, biofuels are pretty much like any other product.〔Ron Oxburgh, "Fuelling hope for the future." ''The Courier-Mail'', August 15, 2007.〕 In 2008 the Nobel prize-winning chemist Paul J. Crutzen published findings that the release of nitrous oxide (N2O) emissions in the production of biofuels means that they contribute more to global warming than the fossil fuels they replace. According to the Rocky Mountain Institute, sound biofuel production practices would not hamper food and fibre production, nor cause water or environmental problems, and would enhance soil fertility.〔Rocky Mountain Institute (2005). ''(Winning the Oil Endgame )'' p. 107. Retrieved December 23, 2009.〕 The selection of land on which to grow the feedstocks is a critical component of the ability of biofuels to deliver sustainable solutions. A key consideration is the minimisation of biofuel competition for prime cropland.〔〔(Growing Sustainable Biofuels: Common Sense on Biofuels, part 2 ) ''World Changing'', March 12, 2008. Retrieved December 24, 2008.〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Sustainable biofuel」の詳細全文を読む スポンサード リンク
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