Corn for Fuel: Not Such a Hot Idea?

According to one scientist, more fossil-fuel energy is required to produce a gallon of ethanol than the energy you get from it

By Alan Hall

A new word -- gasohol -- found its way into the dictionary during the energy crisis of the early 1970s. Blends of gasoline and grain alcohol were produced to reduce U.S. dependence on imported oil, and the government jumped in with tax breaks to help a fledgling industry convert corn to ethanol fuel. More recently, the blends have been promoted as a way to replace gasoline additives that pollute air and water and cut carbon dioxide emissions that may contribute to global warming. And now with rising uncertainty in the Middle East and the possibility of oil-supply disruptions, renewed calls for ethanol production can be expected.

By some measures, the effort to cultivate a home-grown fuel has been a resounding success. A study by the California Energy Commission (CEC) found that 44 ethanol producers, most of them in the Midwest, are now converting about 7% of the annual corn crop into 2.2 billion gallons of ethanol a year at 57 facilities.

The Renewable Fuels Assn. (RFA), a Washington (D.C.)-based industry group, says this flood of alcohol adds $4.5 billion a year to farm revenues, creates 195,200 jobs, pumps $450 million in taxes to states, and improves the U.S. balance of trade by $2 billion. Moreover, the RFA estimates that present use of ethanol fuels will reduce carbon emissions by more than 1.64 million tons during 2001.


  But to one agricultural scientist, the idea of distilling alcohol from corn for fuel just doesn't compute. David Pimentel of Cornell University has done the math. His bottom line: It takes more fossil-fuel energy to produce a gallon of fuel-grade ethanol than burning it will produce. Growing crops to produce fuel amounts to "unsustainable, subsidized food burning," charges Pimentel.

A professor at Cornell's College of Agriculture & Life Sciences, Pimentel conducted a detailed analysis of the corn-to-car-fuel process, which was published in the Encyclopedia of Physical Sciences and Technology in September.

According to Pimentel, the 7,000 pounds of corn produced on an average acre of land can yield about 325 gallons of ethanol. But planting, growing, and harvesting that much corn requires about 140 gallons of fossil fuels and costs $347 -- or about $1.05 per gallon of ethanol. And that's only to grow the grain. The corn must be crushed and fermented, then distilled and processed to extract the alcohol and produce 99.8% pure alcohol suitable for fuel.


  At the end of it all, alcohol production is gushing red ink, says Pimentel. He calculates that it takes 131,000 BTUs to produce a gallon of ethanol. But a gallon of ethanol has an energy value of only 77,000 BTUs. "About 70% more energy is required to produce ethanol than the energy that actually is in ethanol," says Pimental. The deficit: "Every time you make 1 gallon of ethanol, there is a net energy loss of 54,000 BTU."

And the price at the pump? Ethanol from corn costs about $1.75 per gallon to produce, compared with about 95 cents to produce a gallon of gasoline. In addition, it takes 11 acres of land to produce the 850 gallons of alcohol needed to travel 10,000 miles -- the amount of cropland needed to feed seven people for a year, Pimentel says.

Even the approximately $1 billion a year now shelled out in the form of federal and state tax breaks doesn't balance the books, says Pimentel. Since about 70% of the corn grown in the U.S. becomes animal feed, the artificially high prices are reflected at the supermarket in the cost of meat, milk, and eggs.


  Then tack on some hidden costs. Pimentel argues that environmental damages would add on an additional 23 cents per gallon. He calculates that corn production erodes soil about 12 times faster than the soil can be reformed, and irrigating corn mines groundwater 25% faster than the natural recharge rate. "Corn should not be considered a renewable resource for energy production," he argues.

Still, some compelling arguments can be made for producing fuel-grade ethanol. At the head of the list is phasing out MTBE (methyl tertiary-butyl ether), an antiknock fuel additive introduced in 1976 as a substitute for additives using lead. By 2000, an estimated 4.6 billion gallons of MTBE were blended into gasoline in the U.S.

Like its predecessor, tetra-ethyl lead, MTBE, too, had a downside. Soluable in water, MTBE has leaked into the ground from buried tanks and fuel spills. On Sept. 4, the Environmental Protection Agency published new Safe Drinking Water rules that require water systems to monitor for the presence of MTBE.


  Acting ahead of other states and the federal government, California Governor Gray Davis ordered that MTBE be phased out by 2003. In its stead: ethanol -- an estimated 660 million to 950 million gallons a year, a four-fold increase over present demand in that state alone.

For now, it's likely that supply will meet demand. Some 13 new distilleries are already under construction, and 34 others are in the planning stages. By 2005, the CEC estimates that 84 ethanol producers in the U.S. will be churning out nearly 4.5 billion gallons of grain alcohol a year.

But does it make sense to turn the gas-guzzling family buggy into a food gobbler as well? Clearly, few envision the nation's automobiles running on a steady diet of ethanol. Alternatives, such as fuel cells, are already on the road. In addition, using ethanol as an additive can be justified, but corn isn't the only way to get it. Ethanol can also be produced chemically from natural gas, for example.

Predictably, Pimentel's analysis was not greeted with enthusiasm by ethanol advocates. The RFA says the recent study is simply a "regurgitation" of earlier data that "has been fully refuted" by more recent studies. And the National Corn Growers Assn. has placed a point-by-point rebuttal on its Web site.

Without question, developing sources of renewable energy should be given a high priority. Still, the message in Pimentel's analysis is clear: Whether or not his particular calculations stand further tests, a close scrutiny of the data may show that the economics are not always what they seem to be.

For further information:

National Corn Growers Assn.

Renewable Fuels Assn.

Hall is a contributing editor covering science and technology for BusinessWeek Online