Biofuels are a con

In a nutshell, biofuels push up the price of maize and wheat so that poor people are competing for their food with the prices that car ownwers can afford for fuel. 

Secondly plantiations for palm oil, etc. are destroying forests that were soaking up perfectly good carbon and release that carbon when felled or burnt for biofuel plantations. 

Thirdly, by the time they've been processed into fuel, they aren't nearly as carbon neutral as people would like you to believe.

http://www.monbiot.com/archives/2007/03/27/a-lethal-solution/