Nice little article on biofuel policy and technology written by Kimberly Ann Elliott of the Center for Global Development. The government set standards in the mid 2000s to incentivize development of biofuels, and those have more or less backfired for a number of reasons. One is that food prices rose sharply during the period in which the biofuel mandates were beginning to bite; another is that the carbon footprint of the biofuels has turned out to be larger than expected. In other words, the good probably doesn't outweigh the bad right now: we need a technological improvement before we start promoting this stuff.