The great thing about agriculturally produced ethanol is that it is a closed carbon cycle, that is the source of the ethanol(plants) uses the carbon(dioxide) produced from burning it, unlike petroleum that releases stored carbon from the earth,with no direct remedy for reclaiming it. Same thing with bio-diesel. It is just plain better. No argument, unless you are an oil mogul,love smog,cancer,and hate nature. Or you think Chernobyl sounds like a nice vacation spot and won't mind a nuclear waste dump in your back yard because nuclear energy is "smart" energy.
Agricultural ethanol is more efficient than petroleum. When I find the university studies that say so I will post the links.