I won't even go into the rant on how ethanol is an energy loser - it takes more energy to make ethanol than the ethanol itself nets as a fuel. If not for heavy government subsidies, ethanol blend fuels would not exist.
Ironically, taking all of the waste biomatter from crop production (stalks, stems, roots, etc. basically, the majority of each plant that we can't use as food) and converting it to synthetic crude via thermal depolymerization would net an energy gain. However, the resulting fuel after refining would be regular ol' gasoline (or diesel, jet fuel, etc.), which doesn't have the green chic of ethanol. Never mind that the overall carbon emissions would be lower. As they say in the news business, "follow the money trail"...