From TwinCities.com (Green ethanol's dirty fuel):
The latest trend in the green world of ethanol is a surprising one: coal.
Minnesota's first coal-fired ethanol plant soon will begin operation in Heron Lake, and it won't be the last. The high price of natural gas is enticing new plant owners to embrace coal power. But while it may make economic sense, the choice of this fossil fuel to make a renewable one has some people shaking their heads.
Hat tip: Mark Schweitzer