I am a sceptic on ethinol use. To produce, it takes planters, harvesters and crushers, all of which use petrolium. I have always suspected that the farmers could only make a dollar if they bought duty free diesel and sold ethinol at duty included price. ie they are farming the duty, not the earth.
I found this in the renewable energy article Yttrium referenced which makes this point;
Giampietro, Ugliati and Pimentel (1997) say that the ER for ethanol is negative, which would mean that no net fuel energy can be produced.
