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
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
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
"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
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
"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
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,
"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
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