Corn Ethanol Takes More Energy Than It Makes
BERKELEY, California, July 13, 2005 (ENS) - Using ethanol as an additive to make gasoline burn cleaner does more harm than good to the environment, finds a new report by researchers at the University of California, Berkeley. The study concludes that the cumulative energy consumed in corn farming and ethanol production is six times greater than the power the ethanol provides in a car engine.
The paper, published in the journal "Critical Reviews in Plant Science," comes as Congress debates a provision in the energy bill that would double the amount of ethanol to be used as a gasoline additive to five billion gallons a year by 2012.
Ethanol is set to replace methyl tertiary-butyl ether (MTBE), a gasoline additive that has been found to pollute groundwater. Some oil companies have already made the switch to ethanol.
California legislators have opposed the ethanol mandate, saying the requirement to use ethanol would jack up prices at the pump in the state.
"We're embarking on one of the most misguided public policy decisions to be made in recent history," said Tad Patzek, professor of geoengineering at UC Berkeley's Department of Civil and Environmental Engineering.
"We are burning the same amount of fuel twice to drive a car once," said Patzek, who conducted the study with undergraduate students in his civil engineering course.
Patzek and his students found that by the time ethanol is burned as a gasoline additive in our vehicles, the net energy lost is 65 percent, a figure that factors in the energy spent growing the corn and converting it into ethanol.
They conducted the study over a period of four months, reviewing data from government agencies, industry figures and published research papers.
"When you first consider ethanol, it feels like you're being progressive and environmentally friendly," said Jason Lee, an undergraduate at UC Berkeley who helped author the paper. "But, if you dig underneath, you find that it's really misleading. The amount of fuel and oil needed to use ethanol is greater than the value of energy ethanol provides. It's ridiculous to think it would decrease our dependence on oil."
Scientists disagree on the amount of fossil fuel energy it takes to produce ethanol. Both sides of the ethanol debate have calculations to support their position.
A study by U.S. Agriculture Department and Energy Department researchers issued last year shows a net energy gain. The study, led by Hosein Shapouri of the USDA's Office of the Chief Economist, was conducted to refute previous studies by Patzak and others that also found a net energy loss in producing ethanol from corn.
Shapouri's team found that "corn ethanol is energy efficient, as indicated by an energy output/input ratio of 1.67."
The Iowa Corn Promotion Board relies on the USDA study, saying, "Research indicates an approximate 38 percent gain in the overall corn-to-ethanol process and use of that ethanol for fuel."
"Corn yields and processing technologies have improved significantly over the past 20 years and they continue to do so, making ethanol production less and less energy intensive," said the Board.
Patzek said that studies showing energy gain do not take into account the amount of energy stored in the corn.
"The energy stored in the corn is not free," he said. "To grow the corn, you've used up soil and water. We must also account for the disposal of waste water polluted by nitrogen and phosphate fertilizers, as well as by pesticides and herbicides."
When calculating the net energy loss, Patzek and his students took into account the energy equivalent contained within one bushel of corn.
According to the report, it takes a total of 0.87 gallons of gasoline equivalent to grow one bushel of corn, which itself contains 3.17 gallons of gasoline equivalent energy. That calculation includes the fossil energy expended from the use of fertilizer, pesticides, machinery, irrigation and other inputs in corn production.
After the corn is produced, it then takes another 0.89 gallons of gasoline equivalent to ferment and distill one bushel of corn into 2.66 gallons of ethanol, Patzek's team calculates.
In addition, ethanol does not pack as much energy as gasoline because of its lower heating value. The paper points out that the energy of 2.66 gallons of ethanol is equivalent to 1.74 gallons of gasoline.
So, the energy input of 4.93 gallons of gasoline equivalent leads to an energy output of 1.74 gallons of gasoline equivalent, or a net energy loss of 65 percent.
The report also says ethanol may contribute to increased pollution of groundwater if underground storage tanks leak.
"Soil bacteria love ethanol," said Patzek. "If gasoline that contains ethanol leaks, the bacteria in the soil will preferentially metabolize the ethanol instead of the gasoline hydrocarbons. As a result, the subsurface plumes of gasoline will not be degraded and will spread farther out, potentially poisoning more wells."
Because ethanol is also highly corrosive, it cannot be transported over the existing system of pipelines, said Patzek. Ethanol must therefore be transported by train or truck, adding to the final cost of the fuel, he said.
"It makes more sense to produce reformulated gas without any oxygenates, but that is not the popular choice politically," said Patzek. "Additives are the easy way out for everybody concerned."
David Morris of the Institute for Local Self Reliance, based in Minneapolis, is a critic of scientists who conclude that ethanol made from corn is an energy drain.
Over the years more than 20 scientific studies have examined the question, says Morris. "Virtually all studies of ethanol before 1990 showed a net energy loss. Virtually all of the studies after 1990 show a net energy gain. This is because the ethanol industry, in terms of energy use per gallon of ethanol produced, has become much more efficient over the years, as has the farmer, in terms of energy use per bushel of corn grown."
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