Just over a year ago, ethanol manufacturer VeraSun Energy Corp. was one of biofuels' fastest-rising stars. The Sioux Falls, South Dakota-based company had signed partnerships with General Motors Corp. and Enterprise Rent-A-Car Co., was rapidly expanding its production capacity and had announced mergers with ASAlliances Biofuels and US BioEnergy Corp. that would make it one of the largest ethanol companies in the country.

"I think oil companies are definitely going to be players in alternative energy. They bring a lot to the table — money, global reach and, most importantly, distribution." -- Michael Butler, CEO, Cascadia Capital