28 June 2005
touted as an alternative fuel of the future, may
eat up far more energy during its creation than it
winds up giving back, according to research by a
UC Berkeley scientist that raises questions about
the move toward its widespread use," writes Elizabeth
clean-burning fuel produced from renewable crops
like corn and sugarcane, ethanol has long been a
cornerstone of some national lawmakers' efforts to
clear the air and curb dependence on foreign oil.
California residents use close to a billion
gallons of the alcohol-based fuel per year.
in a recent issue of the journal Critical Reviews
in Plant Sciences, UC Berkeley geoengineering
professor Tad Patzek argued that up to six times
more energy is used to make ethanol than the
finished fuel actually contains.
fossil energy expended during production alone, he
concluded, easily outweighs the consumable energy
in the end product. As a result, Patzek believes
that those who think using the "green"
fuel will reduce fossil fuel consumption are
deluding themselves -- and the federal
government's practice of subsidizing ethanol by
offering tax exemptions to oil refiners who buy it
is a waste of money.
tend to think of ethanol and see an endless cycle:
corn is used to produce ethanol, ethanol is burned
and gives off carbon dioxide, and corn uses the
carbon dioxide as it grows," he said.
"But that isn't the case. Fossil fuel
actually drives the whole cycle."
investigation into the energy dynamics of ethanol
production began two years ago, when he had the
students in his Berkeley freshman seminar
calculate the fuel's energy balance as a class
the class took into account little-considered
inputs like fossil fuels and other energy sources
used to extrude alcohol from corn, produce
fertilizers and insecticides, transport crops and
dispose of wastewater, they determined that
ethanol contains 65 percent less usable energy
than is consumed in the process of making it.
at the results, Patzek began an exhaustive
analysis of his own -- one that painted an even
bleaker picture of the ethanol industry's long-
grain apart, fermenting it, distilling it and
extruding it uses a lot of fossil energy," he
said. "We are grasping at the solution that
is by far the least efficient."
report also highlights the potential environmental
hazards of ethanol production.
you dump nitrogen fertilizer on corn fields, it
runs away as surface water, into the Mississippi
River and Gulf of Mexico," he said.
excess nitrogen introduced into the water causes
out-of-control algae growth, creating an
oxygen-poor "dead zone" where other
marine plants and animals cannot survive. And
while ethanol produces fewer carbon monoxide
emissions than regular gasoline, some researchers
have found that ethanol releases high levels of
nitrogen oxide, one of the principal ingredients
of smog, when burned.
has long been touted not just for its promise as a
renewable fuel, but for its usefulness as a
gasoline additive. Fossil fuels blended with it
produce fewer carbon monoxide emissions than
regular gasoline and have a higher octane rating,
meaning they burn more evenly and are less likely
to cause engine knocking. While most gasoline sold
in the United States now contains approximately 5
percent ethanol, some cars -- such as the Ford
Explorer and Chevy Silverado -- can run on fuel
blends containing up to 85 percent.
his work has been vetted by several peer-reviewed
scientific journals, Patzek has had to deflect
criticism from a variety of sources. David Morris,
an economist and vice president of the
Minneapolis-based Institute for Local
Self-Reliance, has attacked the Berkeley
professor's analysis because he says it is based
on farming and production practices that are
rapidly becoming obsolete.
figures (regarding energy consumed in fertilizer
production) are accurate for older nitrogen
fertilizer plants, but newer plants use only half
the energy of those that were built 35 years
ago," he said. He also cited the increasing
popularity of no-till farming methods, which can
reduce a corn farm's diesel usage by 75 percent.
"With hydrogen fuel, people are willing to
say, '25 years from now it will be good.' Why
can't we also be forward-looking when it comes to
Shapouri, an economist at the U.S. Department of
Agriculture, has also cracked down on Patzek's
true that the original ethanol plants in the 1970s
went bankrupt. But Patzek doesn't consider the
impact new, more efficient production technologies
have had on the ethanol industry," he said.
most recent analysis, which the USDA published in
2004, comes to the exact opposite conclusion of
Patzek's: Ethanol, he said, has a positive energy
balance, containing 67 percent more energy than is
used to manufacture it. Optimistic that the
process will become even more efficient in the
future, he pointed out that scientists are
experimenting with using alternative sources like
solid waste, grass and wood to make ethanol. If
successful on a large scale, these techniques
could drastically reduce the amount of fossil fuel
needed for ethanol production.
contributors to the debate argue that ethanol's
net energy balance should not be the sole
consideration when policymakers are evaluating its
usefulness -- factors like the fuel's portability
and lower carbon monoxide emissions need to be
considered as well.
what if we have to spend 2 BTUs for each BTU of
alcohol fuel produced?" reads an editorial in
the Offgrid Online energy newsletter. "Since
we are after a portable fuel, we might be willing
to spend more energy to get it."
University ecology Professor David Pimentel,
however, sides with Patzek, calling production of
ethanol "subsidized food burning."
USDA isn't looking at factors like the energy it
takes to maintain farm machinery and irrigate
fields in their analysis," he said, adding
that the agency's ethanol report contains overly
optimistic assumptions about the efficiency of
farming practices. "The bottom line is that
we're using far more energy in making ethanol than
we're getting out."
thinks lawmakers and environmental activists need
to push ethanol aside and concentrate on more
sustainable solutions like improving the
efficiency of fuel cells and hybrid electric cars
or harnessing solar energy for use in transport.
If they don't, he predicts economics will
eventually force the issue.
government funds become short, subsidies for fuels
will be looked at very carefully," he said.
"When they are, there's no way ethanol
production can survive."