Biofuels are an exciting issue right now. We're seeing a lot about it in the media. There are two types of biofuels. There are lignocellulosic biofuels, which are taken, generally speaking, from the by-product of food crops or other crops that are non-food and grow extremely rapidly and with very few external inputs. Study after study has now shown that those kinds of biofuels give you a net energy improvement and a net greenhouse gas reduction. With other types of biofuels--the ubiquitous example is corn for fuel--study after study is showing that you may actually be coming out expending more energy than you're saving in bringing that kind of fuel to market. So that, again, does not come within the definition of sustainability.
On April 28th, 2008. See this statement in context.