Paying too much attention to GM/Ford BS
Look at what Koennigsegg gets out of an E100 engine versus the same engine running on gas. At the same fuel economy, they lose 200hp running on petrol. Your problem is that you're looking at the impact on fuel economy on the crap engines GM and Ford were making 10-20 years ago. Ethanol has less energy than gasoline, just like diesel does, but it IS more efficient, for the same reasons diesel is, which is why F1 and Indycar switched over years ago. Get a better car.
That said land use to in acres to energy in biodiesel to acre to energy in ethanol is can't be much worse. If the argument is don't make biodiesel buy Brazilian ethanol, they can't do math.
