Harvard enviornmental scientist Michael McElroy weighs in on ethanol in the the Nov-Dec Harvard Magazine. As the title implies he is skeptical about the advisability of subsidizing ethanol. http://harvardmagazine.com/on-line/110634.html

Comment: Ethanol subsidies are political payoffs to corporate corn farmers like Archer-Daniels Midland. Ethanol won't significantly reduce our dependence on imported oil, and it won't make a big dent in greenhouse gas emissions. Effective legislation requiring easy improvements in motor vehicle fule economy, using already existing technology, would achieve much more toward reducing greenhouse gases and dependence on oil imports than subsidizing the production of ethanol. A 30 percent improvement in vehicle fuel economy would be easy to accomplish if our leaders in Washington made up their mind to do it.