A boom in the production of biofuel was under way in 2007, especially in the United States, where in January about 75 refineries for producing the biofuel ethanol from corn (maize) were being built or expanded. This construction, not including additional facilities on the drawing board, was expected to double existing capacity, and the demand for corn pushed its price so high that American farmers planted more land with the crop than they had in a generation. Biofuel was perceived as a beneficial alternative to petroleum and other fossil fuels as the price of petroleum rose during the year to record levels and worldwide concern increased about how greenhouse-gas emissions from petroleum-derived fuels were contributing to climate change in the form of global warming. Despite its perceived economic and environmental benefits, however, many critics were expressing concerns about the scope of the expansion of certain biofuels because of their potential to create new problems.
Biofuels are fuels that are derived from biomass— that is, plant material or animal waste. Since such materials can be replenished readily, biofuels are a from biomass that has a high content of cellulose. This cellulosic ethanol could be produced from abundant low-value material, including wood chips, grasses, crop residues, and municipal waste. The mix of commercially used biofuels will undoubtedly shift as these fuels are developed, but the range of possibilities presently known could furnish power for transportation, heating, cooling, and electricity.
In evaluating the economic benefits of biofuels, the energy required for producing them has to be taken into account. For example, in growing corn to produce ethanol, fossil fuels are consumed in farming-equipment use, in fertilizer manufacturing, in corn transportation, and in ethanol distillation. In this respect ethanol made from corn represents a relatively small energy gain; the energy gain from sugarcane is greater and that from cellulosic ethanol could be even greater. Biofuels supply environmental benefits but, depending on their implementation, can also have serious drawbacks.
