Biofuels Are an Environmental Dead End

By Tom Philpott, Grist.org. Posted December 13, 2006.

Any worthy idea can withstand and even be improved by naysayers; scolds and skeptics play the useful role of pointing out obvious flaws. The biofuels industry has no more persistent, articulate, and scathing critic than David Pimentel, professor emeritus of entomology at Cornell University.

In 1979, with the price of oil surging and a politically connected company called Archer Daniels Midland investing heavily in ethanol production, the U.S. Department of Energy invited Pimentel to chair an advisory committee to look at ethanol as a gasoline alternative. The committee's conclusion: ethanol requires more energy to produce than it delivers.

That assessment didn't stop the government from enacting a variety of subsidies for ethanol, which has since developed into a multibillion-dollar industry. Nor has Pimentel refrained from issuing a series of scholarly articles claiming to show that, after decades of steady government support, ethanol remains an energy bust.

Over the years, Pimentel has become an increasingly controversial figure. The U.S. Department of Agriculture now claims that corn ethanol delivers a modestly positive net energy balance [PDF], a conclusion recently endorsed by a study from University of Minnesota researchers. Yet Pimentel's provocations continue. Not only is corn-based ethanol a net energy consumer, he says, but cellulosic ethanol -- simultaneously biofuel's holy grail and sacred cow -- is "worse."

Pimentel thinks biofuels are an environmental dead end and enthusiasts for crop-based energy would do well to at least examine his analysis.

Philpott: You claim corn ethanol's energy balance is negative, and there's a growing consensus that it's positive. Why the difference?

Pimentel: Pro-ethanol people make it out to be positive by omitting many of the inputs that go into corn production. For example, they omit the farm labor -- I'm not talking about the farm family, I'm talking about the farm labor. They omit the farm machinery. They omit the energy to produce the hybrid corn. They omit the irrigation. I could go on and on. Anyway, if I did all of those manipulations, I could achieve also a positive return.

However, that's not the way these assessments are made. You can go check the noted agricultural economists who have looked at corn as well as other crops, and they do include the labor, they include the farm machinery, they include repair of the farm machinery, and so forth and so on. And so, those are all inputs that the ag economists include. Why are the pro-ethanol people leaving them out?

Philpott: When you say that the ethanol crowd fails to include the farm machinery, are you talking about the energy that's needed to manufacture a tractor, for example?

Pimentel: That's right. Or an automobile used by the farmer.

Philpott: From your experience, how do these researchers justify that omission?

Pimentel: They don't. They just omit it.

Philpott: I also see that in your studies, your calculation of how much energy goes into producing synthetic fertilizer is higher than the USDA's assessment. Why that difference?

Pimentel: Our data come from the U.N. Food and Agriculture Organization. We're actually using a lower number than [the FAO's]. We're using 16,000 kilocalories per kilogram [of fertilizer], and I say the FAO is using 18,000. So again, we're using the most accurate data that are available, and not trying to manipulate these numbers.

Philpott: Another place where you clash with other researchers is over the byproducts of ethanol: stuff like distillers grains that go into animal feed, etc. For those researchers, byproducts are what push ethanol's energy balance solidly onto positive ground.

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Grist staff writer Tom Philpott farms and cooks at Maverick Farms, a sustainable-agriculture nonprofit and small farm in the Blue Ridge Mountains of North Carolina.

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