Sustainable liquid biofuels and their environmental impact

Abstract

In whatever measure liquid biofuels are produced, they avoid the use of politically and economically unstable petroleum. However, there has been much debate regarding their environmental impact and sustainability. Corn ethanol manufacturing uses large quantities of fossil fuels, which, although locally produced, create doubt on whether its continual use will bring any clear economic and environmental benefits. On the other hand, biodiesel, because it enjoys a simpler and thus efficient manufacturing process, shows more clarity as to the environmental benefits it provides, but its sustainability at a significant scale is not clear due to the low productivity of its crops. Brazil's ethanol industry, which is based on sugarcane, has shown that it is possible to be efficient, both environmentally and economically in the implementation of a biofuel infrastructure. Very akin to sugarcane ethanol technology is cellulosic ethanol. A cellulosic ethanol infrastructure can make use of crops that have higher productivities and lower environmental impact. In addition, the conversion process uses very little fossil fuels, which makes it even more sustainable and environmentally benign. This article describes the infrastructure necessary for the implementation of sustainable biofuels, discusses their projected benefits, their environmental impact, and the logistics needed for their sustainability. ©2007 American Institute of Chemical Engineers.