Running on Empty?
‘Great ethanol debate’ waged at NCGA forum
By Stephen Thompson
Assistant Editor
oes making
ethanol consume
more
energy than it
produces? Will
ethanol be a key component
in helping the nation reduce
its voracious appetite for foreign
oil, or just be a bit player
on the energy front?
That’s been the subject of
an intense debate for years,
and two panels of experts
squared off recently to try to
settle the question. The
experts presented starkly differing
views during “Ethanol
Energy Balance,” an open
forum held Aug. 23 at the
National Press Club in
Washington, D.C., sponsored
by the National Corn
Growers Association
(NCGA).
Dr. David Pimentel, a professor
emeritus of entomology at
Cornell University, and Dr. Tad W.
Patzek, an associate professor of chemical
engineering at the University of
California-Berkeley, argued that
ethanol production from corn is a net
energy loser and contributes to global
warming. They also say it could never
provide more than a tiny portion of
the nation’s fuel needs.
Dr. Bruce Dale of Michigan State
University and Dr. John Sheehan of
the National Renewable Energy Lab
countered that Pimentel and Patzek
are running on empty, and that their
conclusions are based on faulty data.
Patzek and Pimentel’s conclusions
have received some notoriety in the
media, leading some ethanol advocates
to accuse them of “duping” the public.
The resulting controversy encouraged
the NCGA to hold the forum and,
later the same day, a follow-up seminar:
“Renewable Energy: Dynamic
Possibilities,” during which the
emphasis was more on the potential of
ethanol and biodiesel.
Energy consumed vs. yield
The disagreement centers on the
amount of total energy inputs required
to produce ethanol. These inputs
include: the fuel to power machinery
needed to grow and harvest the feedstock,
such as corn; the petroleum used
in manufacturing the required fertilizers,
pesticides and herbicides for the
feedstock; the energy expended to
transport the feedstock to the processor,
and the energy used by the ethanol
processing plant.
Pimentel has argued for many years
that the total energy inputs, when
added up, make ethanol a “net energy
loser,” and that relying on ethanol as a
fuel source would cause significant
environmental impacts.
In a paper he published in 1998,
Energy and Dollar Costs of Ethanol
Production with Corn, he says:
“Assuming a net production of 50
gallons of fuel per acre of corn, and
assuming that all cars in the United
States were fueled with ethanol, a
total of approximately 2 billion acres
of cropland would be required to
provide the corn feedstock. This
amount of acreage is more than five
times all the cropland that is actually
and potentially available for all crops
in the future in the United States.”
Pimentel spoke to a largely proethanol
crowd of corn producers and
their representatives. Ethanol, he said,
is not a true renewable energy source,
because it requires more energy in its
production than is extracted from the
finished product. According to his calculations,
ethanol takes about 1.15
BTUs (British Thermal Units) of
input for every 1 BTU of output.
Other reasons ethanol production is
undesirable, said Pimentel, include the
environmental impact of corn production.
“Corn production causes more
soil erosion than any other crop.” He
added that growing corn also requires
more insecticide, herbicide, and nitrogen
fertilizer than most other crops,
with the result that corn production in
the United States causes $45 billion in
environmental and other damage each
year. He said it requires 1,725 gallons
of water to produce 1 gallon of
ethanol.
Pimentel also claimed that, with
more than 3 billion malnourished people
in the world, burning corn for
energy poses serious ethical questions.
Pimentel advocated using other fossil
fuels to replace petroleum. “We can
use coal to make diesel and gasoline,”
he said, at an energy cost of 2 BTUs
to produce 1 BTU of fuel.
Patzek told the audience that simply
keeping U.S. car tires properly inflated
would save more petroleum than
ethanol production. “Each year the
U.S. uses more energy than our vegetation
can sequester as biomass,”
Patzek argued. He said that in 2003,
the United States used 105 times more
energy than was required to feed the
population, and biomass as a source of
energy in the United States is heavily
subsidized by petroleum.
According to Patzek, the amount of
ethanol energy that can be extracted
from 1 square meter of land is “tiny”
— about one-tenth of 1 watt — compared
with energy available from other
sources. “A wind turbine generates 1
watt per square meter, which can be
converted to mechanical work almost
perfectly,” he said. “A photovoltaic cell
generates between 10 and 20 watts per
square meter. Thus, wind turbines and
photovoltaic cells are 20 to 100 times
more efficient in delivering mechanical
work than corn ethanol.”
Patzek showed a graph comparing
projected petroleum consumption and
ethanol production in 2012. “Anhydrous
ethanol replaces 1.5 percent of
petroleum in 2004,” he said, “and will
replace another 1 percent in 2012” —
far too little to make an impact on
U.S. petroleum consumption.
Ethanol advocates’ response
John Sheehan countered that
ethanol’s return on fossil energy
investment is positive. Peer-reviewed
Department of Energy and USDA
research, he said, shows that producing
1 unit of ethanol energy from corn
requires only 0.75 of an equivalent unit
of petroleum energy, for a net gain of
25 percent. Using switchgrass for
ethanol production results in even
higher energy gains: up to 72 percent.
“Pimentel’s methodology assumes
inputs that are too high,” Sheehan said.
“No one is saying that biofuels will
replace petroleum,” said Sheehan, but
he added that the value of biofuels in
reducing the U.S. dependence on foreign
oil is “critical.”
Bruce Dale not only disputed the
Pimentel data, he also attacked the
very premise of Pimentel’s argument:
that the net energy balance of a fuel is
a valid yardstick of its usefulness. “I
come to bury ‘net energy,’ not to
praise it,” he said, referring to the
Pimental’s cost/benefit formula.
Dale called net energy a “convenient
fiction, an academic toy” that
“doesn’t relate to the real world.” The
reason, he said, is that it doesn’t
address the quality of various forms of
energy — treating solar, natural gas,
coal, petroleum, etc., as equal. “But all
energy is not created equal,” he
declared, arguing that the quality of
energy — that is, its readiness to be
converted into the required work or
service — is a vital factor in determining
its value.
“We do not need energy per se,”
said Dale. “We need the services energy
provides,” including electricallypowered
equipment and appliances,
heat and transportation. The U.S. has
lots of coal and natural gas,” he said,
“But they don’t work in the gas tank.
They have the wrong energy quality.”
Solutions, he said, “will require making
comparisons and choices between
real alternatives.”
Dale gave an example: Using the
criterion of Pimentel and Patzek, he
said, the “net energy” of electricity
produced from coal is minus 235 percent,
because it takes three calories of
coal to produce one calorie of electricity.
But, “Electricity is higher quality
energy than coal.” Refining crude oil
into jet fuel, diesel or gasoline results
in a net energy balance of minus 39
percent, as opposed to minus 29 percent
for making ethanol from corn,
according to Pimentel’s figures.
If ‘net energy’ was a good yardstick,
“we should shut down all coal-electricity
generation and all oil refineries,”
Dale said.
During the question-and-answer
period, Pimentel was asked about
ethanol production’s relation to animal
feed. He replied that using corn for
ethanol had resulted in higher beef
prices. Dale challenged that assertion,
asking Pimentel how he could reconcile
his statement with the fact that the
United States currently has the highest
stocks of corn in history — more than
2 billion bushels of surplus corn last
year.
Other questions centered on the
data used by the anti-ethanol faction in
making its calculations. Both Pimentel
and Patzek were accused of using outdated
data from the 1980s, but
Pimentel asserted that, except for figures
regarding the energy costs of the
concrete used in building ethanol
plants, his figures were up-to-date.
Biofuels touted as efficient
The “Dynamic Possibilities” forum
was devoted to supporters of ethanol
and other biofuels, many of whom
continued to criticize Pimentel and
Patzek’s findings.
Roger Conway, a USDA researcher,
called the concept of net energy a false
standard, and claimed that Pimentel
and Patzek “picked and chose” data to
get a desired result, treating as consistent
information from surveys gathered
with differing methods and criteria.
David Morris, of the Institute for
Local Self Reliance, said that biofuels
are not a silver bullet for the energy
industry, but could replace 70 percent
of the petroleum used for fuel and
other purposes. He pointed out that
the co-products of ethanol and
biodiesel were “significantly valuable,”
and said that Pimentel and Patzek did
not include the true value of such
products as distillers grains and soy
meal, both excellent animal feeds, in
their calculations.
“We’re not dying from a shortage of
starch,” Morris said, referring to the
ingredient of corn that is used in the
fermentation of ethanol, leaving
behind high-protein distillers grains.
Even with biofuels, Morris said, the
United States must reduce its overall
energy consumption.
Morris has just published a new
paper: Carbohydrate Economy, Biofuels
and the Net Energy Debate (on-line at:
www.newrules.org) which looks at the
comparative data that underlies the
ethanol debate. In it, he says
Pimentel’s “aversion to including an
energy credit for [ethanol] coproducts
is puzzling. If we use the energy used
to grow and process a crop on the
input side of the equation, we should
include all the energy value of all the
end-products on the output side.”
Morris also said biofuels represent
a tremendous opportunity for farmers
to add value to their crops, saying
there could be 1 million farmers owning
shares in a biorefinery by 2050.
Michael Wang, of the Argonne
National Laboratory’s Center for
Transportation Research, said that
many studies contradicted the claims
of Pimentel and Patzek. He said that
Argonne’s study of the same subject
concluded that producing corn
ethanol requires 26 percent less energy
than it contains, and that cellulosic
ethanol, made from switchgrass and
other inexpensive plant sources,
requires a whopping 90 percent less,
partly because its byproducts can be
burned for energy to power the processing
plant.
“A review of Pimentel/Patzek,” said
Wang, “reveals that they made pessimistic
assumptions, and doublecounted
certain energy costs without
detailed elaboration.” Wang accused
Pimentel and Patzek of consistently
overestimating energy requirements
for both farming and processing of
corn for ethanol, including calculating
ethanol plant energy use at 30 percent
above actual figures.
Other speakers attacked Pimentel
for using extraneous data in their calculations,
such as the food eaten by
farmers and workers engaged in
ethanol production and the energy cost
of building farm machinery, and
claimed that their results were not
peer-reviewed before publication.
For more detailed reading:
A copy of Dr. Patzek’s presentation
to the forum is available on the
Internet at:
http://www.berkeley.edu/news/media/r
eleases/2005/08/NPC_briefing_Patzek
.pdf. Other presentations can be found
at the NCGA Web site at:
http://www.ncga.com/ethanol/debunking/
ForumPresentation.htm.
David Pimentel’s 1998 report,
Energy and Dollar Costs of Ethanol
Production With Corn is available at:
http://hubbert.mines.edu/news/Piment
el_98-2.pdf. Pimentel and Patzek’s
article, Ethanol Production Using Corn,
Switchgrass and Wood; Biodiesel
Production Using Soybean and Sunflower,
was published in in the March, 2005
edition of Natural Resources Research
magazine.
