Ethanol conversion is 30% efficient, and to run cars on pure ethanol will require engine modification.In newer cars it means the computer chip. 3-$500. Without subsidies it costs about $80/barrel equiv.
A better technology is Thermochemical Conversion, it is 80% efficient, and will also handle most of this country's solid waste problems. The problem is, that it creates oil at an unsubsidized cost of $80/barrel. Thus, it will compete directly with cheep middle eastern oil. (All they would have to do is drop their price and we are skewered.)
Therefore ethanol is a better short term solution, since it gets our basic transportation costs out of the hands of foreign oil. Caveat: Ethanol/Gasoline blends are a waste of time, since they compete with oil, and for that, they are way too expensive.
" The problem is, that it creates oil at an unsubsidized cost of $80/barrel."
For transporation fuel, we have all we need for the next 100 years in Canada and Colorado for $20/ barrel cost.
Let's invade Canada instead of Iran.