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
"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
"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
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
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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