But that is determined by the pricing, if it is cheaper to "produce" than fossil fuel than it will be used more. Now the problem its causing is farmers replacing wheat/rice or other "edible-item" fields with "corn for ethanol" which probably resulting in "food shortage" globally.
by efficient I mean the energy that goes into producing ethanol is more than the energy released by ethanol upon combustion. this is factoring in the energy utilized in fertilizers, production etc. not just an issue of pricing but how it is produced.