Bring on the biofuels

Ethanol's bad rap for energy efficiency is bogus.


Andrew Leonard
January 28, 2006 3:19AM (UTC)

Want to get a roomful of biofuel geeks hopping mad? Tell them that the production of biofuels like ethanol or biodiesel consumes more energy than it delivers. In the world of renewable energy, that's a cardinal sin. If more fossil fuel is consumed making a gallon of ethanol than in making a gallon of gasoline, why even bother?

Getting hard data on the net energy costs of biofuels is a challenge. If you start Googling around, you end up lost in a maze of competing studies, most of which are tough for the layman to evaluate. Which is why I went on full alert this morning when Grist informed me of a paper in this week's Science that evaluated a sheaf of studies and concluded that the research stating corn-based ethanol is not energy efficient is seriously flawed.

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This is important news, and I wanted to know more. I paid $10 for access to the Science article (which I later learned was unnecessary) and then promptly called up the lead author of the paper, Alex Farrell, an assistant professor at the Energy and Resources Group at the University of California at Berkeley. How did he and his colleagues come to their conclusions?

The first problem in doing research of this kind, said Farrell, is choosing your assumptions, or, in more jargon-ish language, setting the proper "system boundaries."

Which means, basically, figuring out what's inside the system, and what's outside. "For example," says Farrell, "when examining the system of ethanol production, most people think that the fossil fuels consumed in the tractors on the farm are inside the system. But what about the factory that made the farm machinery?"

And you can keep going. What about the energy expended mining the ore that becomes the steel that is used to build the tractor? What about the manufacturing of the mining equipment? And so on.

Farrell and his co-authors were able to compare the studies they were evaluating by plugging their data into a common set of system boundary parameters. And one of the major things they found was that the most important studies declaring ethanol was not energy efficient had left out a pretty major factor. They ignored the energy savings generated by the "co-products" that resulted from ethanol manufacture.

Such co-products include corn gluten feed, corn oil and other materials for which there are preexisting markets. If you include the energy value of those co-products in the overall system of ethanol production, you end up with a net-positive energy efficiency.

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[UPDATE: Alex Farrell informed me over the weekend that I goofed a bit here. It wasn't solely the co-products that altered the energy-efficiency stats. Farrell and his co-authors also identified problems with "data that is obsolete or of dubious and unverifiable quality. In terms of net energy, the most important of these data are the energy required to manufacture the farm machinery." Thus, it was the combination of the co-products and the data adjustments that led to the new, positive values for ethanol.]

This was encouraging news. (All the data examined by Farrell and his co-authors is online, including the spreadsheet model that they used to make their calculations.)

But what would happen, I asked, if you tweaked the models a little further: What if the tractors doing the plowing weren't consuming fossil fuels? What if they were running on ethanol too?

Farrell enjoyed hearing that question. "That's the next thing to do," he said, his tone taking on a bit more urgency. "These are all studies of existing systems, or systems as they were in the past. If we think we want to use biofuels in the future, you don't want to get too wrapped around the axle with what we did yesterday, or what plants we use for feedstock today."

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Higher levels of energy efficiency as well as a significant decrease in greenhouse gas emissions, said Farrell, could come from the employment of "cellulosic technology," which would allow ethanol to be manufactured from plant fibers. And greater attention to ensuring renewable energy inputs at every stage of the complete life cycle of green biofuel production would also increase total energy efficiency.

The ultimate goal, said Farrell, clearly launching into one of his favorite hobbyhorses, is the establishment of "green markets."

"One of the possible outcomes of this research is a much better economy for farmers. We think if we really pay attention to what we care about -- lowering imported petroleum, reducing greenhouse gases -- we establish markets for green fuels and end up with a system where the current method of supporting ethanol production through incentives and subsidies can be eliminated."

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Finally, I asked Farrell about a concern expressed by some environmentalists that the growing demand for biofuels could have its own negative environmental impact -- such as the cutting down of rain forests to make room for soybeans, palm oil and other biofuel feedstocks. Wouldn't that defeat the purpose?

"Promoting biofuels could very easily have negative outcomes," conceded Farrell.

But in Farrell's vision of self-supporting "green markets," properly defining "green" would require a full appraisal of the production process.

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"In that definition of green we would not permit growing biofuels in a rain forest," said Farrell. "So it becomes a labeling problem. California wants to cut greenhouse gas emissions, and the governor's current targets are ambitious. But if we want to do that, and use ethanol and biodiesel to get there, the state is going to have to figure out how those fuels are produced. This is what I mean by creating a market for green fuels. It's not simply enough to say that it is a 'renewable' fuel -- unless there are specific definitions and monitoring protocols. It is a serious concern, but it is not something that means biofuels are impossible to do the right way."


Andrew Leonard

Andrew Leonard is a staff writer at Salon. On Twitter, @koxinga21.

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