Another major point to consider in the energy balance consideration is that the goal here is portable fuel. If it takes three units of stationary energy to produce one unit of portable energy, so what? What is the cost of the stationary energy input? Say the energy involved in production is largely nuclear, wind, or solar, not a single one of which is a portable source and the latter two of which are near-free and non-polluting. What does it matter how much windmill spinning is required to produce a gallon of ethanol, or how many watts a solar still absorbs while distilling it?

All that said, Brazilian sugar cane ethanol makes sense–for Brazil. Completely different cost-efficiency-resource structure. But in general grain ethanol is at best only a partial substitution for America, not a replacement. Cellulosic ethanol show much greater promise as a sustainable alt-fuel.  Grain ethanol was indeed foisted ito the political structure as a "desirable" alternate only because of the frm-state and Big Ag politics involved.

A classic educational exercise in the law of unintended consequences.