everything I have read says that corn-based ethanol can't be made to work as a net environmental or energy-win. switchgrass is far better in terms of efficiency and smaller impact on the biome. also, corn in the heartland = deadzone in the gulf of mexico, too, as the fertilizer run off causes such a severe algae bloom where the Mississippi lets out that there's no oxygen in the water for hundreds of square miles.

if you are interested in sources let me know and I will pull some up. Science News has had a bunch of articles on this recently though.

I think my ESO's high school friend is currently working for a company looking at turning farm waste into ethanol (e.g. corn stalks). I don't know how well their project is faring.