From a reader:

Yeah, I’m from Omaha, so you might be skeptical about a comment coming from the “Daharan of ethanol”, but consider this.
Ethanol is really taking off. And not just because of government subsidies. That is the ‘big oil’ talking point, and I get it. But the simple truth is that the ethanol plants being built today use half as much energy and half as much water as the plants that came on line in the last three years. And the plants currently on the drawing board are even more efficient: They will derive all the power and water they need from the corn itself.
Who knows what the future will hold. But don’t fall into the trap of thinking that the cost/benefits of ethanol are a law of nature. We are getting more and more energy out of less and less input every day.
There is more to ethanol than you think.

Me: I’m still not buying it. And I don’t see how the government subsidies criticism is just a Big Oil talking point or how that would automatically make it wrong. The fact that ethanol is “taking off” is not proof one way or the other about the reason why it is taking off. But I’ll keep an open mind.