Don't Miss Out

Subscribe to OCA's News & Alerts.

Cook Organic not the Planet Campaign

70 Percent More Energy Required to Make Ethanol than Actually is in Ethanol: Cornell

CU scientist terms corn-based ethanol 'subsidized food burning'

Neither increases in government subsidies to corn-based ethanol fuel nor hikes in the price of petroleum can overcome what one Cornell agricultural scientist calls a fundamental input-yield problem: It takes more energy to make ethanol from grain than the combustion of ethanol produces.

At a time when ethanol-gasoline mixtures (gasohol) are touted as the American answer to fossil fuel shortages by corn producers, food processors and some lawmakers, Cornell's David Pimentel takes a longer range view.

"Abusing our precious croplands to grow corn for an energy-inefficient process that yields low-grade automobile fuel amounts to unsustainable, subsidized food burning," said the Cornell professor in the College of Agriculture and Life Sciences. Pimentel, who chaired a U.S. Department of Energy panel that investigated the energetics, economics and environmental aspects of ethanol production several years ago, subsequently conducted a detailed analysis of the corn-to-car fuel process. His findings will be published next month in the forthcoming Encyclopedia of Physical Sciences and Technology.

Among his findings:

* An acre of U.S. corn yields about 7,110 pounds of corn for processing into 328 gallons of ethanol. But planting, growing and harvesting that much corn requires about 140 gallons of fossil fuels and costs $347 per acre, according to Pimentel's analysis. Thus, even before corn is converted to ethanol, the feedstock costs $1.05 per gallon of ethanol.


* Adding up the energy costs of corn production and its conversion to ethanol, 131,000 Btu are needed to make 1 gallon of ethanol. One gallon of ethanol has an energy value of only 77,000 Btu. "Put another way," Pimentel said, "about 70 percent more energy is required to produce ethanol than the energy that actually is in ethanol. Every time you make 1 gallon of ethanol, there is a net energy loss of 54,000 Btu."

* Ethanol from corn costs about $1.74 per gallon to produce, compared with about 95 cents to produce a gallon of gasoline. "That helps explain why fossil fuels -- not ethanol -- are used to produce ethanol," Pimentel said. "The growers and processors can't afford to burn ethanol to make ethanol. U.S. drivers couldn't afford it either, if it weren't for government subsidies to artificially lower the price."


* The approximately $1 billion a year in current federal and state subsidies (mainly to large corporations) for ethanol production are not the only costs to consumers, the Cornell scientist observes. Subsidized corn results in higher prices for meat, milk and eggs because about 70 percent of corn grain is fed to livestock and poultry in the United States. Increasing ethanol production would further inflate corn prices, Pimentel said, noting: "In addition to paying tax dollars for ethanol subsidies, consumers would be paying significantly higher food prices in the marketplace."


* The average U.S. automobile, traveling 10,000 miles a year on pure ethanol (not a gasoline-ethanol mix), would need about 852 gallons of the corn-based fuel. This would take 11 acres to grow, based on net ethanol production. This is the same amount of cropland required to feed seven Americans.
