Posted on 08/11/2003 11:01:40 AM PDT by NativeNewYorker
In what seems to be the never-ending saga of whether it takes more energy
to produce ethanol than it
saves, Cornell University Professor David Pimentel has issued an update to his
2001 study. But while
Pimentel found that it still takes more energy to produce ethanol than it saves,
the number has dropped
from 70% down to 29%.
Pimenel's findings were published in the latest issue of the journal
Natural Resources Research.
“[S]cientific studies have concluded that ethanol production does not
provide a net energy balance, is
not a renewable energy source, is not an economical fuel and its production and
use contributes to air
pollution and global warming,” Pimentel said in his paper, citing a handful of
previous studies, including
three of his own and testimony from the National Petrochemical & Refiners
Association.
Specifically, the total energy input to produce a gallon of ethanol is
99,119 Btu, however a gallon of
ethanol has an energy value of only 77,000 Btu, Pimentel claims. “Thus, there is
a net energy loss of 22,119
Btu per gallon of ethanol produced. Put another way, about 29% more energy is
required to produce a
gallon of ethanol than the energy that actually is in the gallon of ethanol
produced,” he added, noting at the
same time that ethanol has only two-thirds the energy content of the same volume
of gasoline. In Pimentel's
last study done in 2001, he found it took 70% more energy to produce ethanol
than it saved (see OFN,
8/27/01).
Among the changes, Pimentel increased corn yield from 126 bushels/acre,
to 136 bushels/acre and he
included a mean value of the energy input in irrigating the land used to grow
the corn. In his 2001 study,
Pimentel assumed 100% of the land in which corn is grown is irrigated, when USDA
estimates that number
to only be 15%, something USDA analysts brought up when critiquing the 2001
study.
Pimentel also claimed that ethanol is generally priced higher at the
gasoline pump than gasoline, yet
yields poorer mileage per gallon, without the $1.4 billion/yr in incentives,
ethanol couldn't compete
economically in the gasoline market and using corn as the feedstock takes away
from food supply.
Pimentel's data “is an improvement, but he still is using these very wild
assumptions,” said USDA
Agricultural Economist Hosein Shapouri, one of three authors of a 1995 study,
which found that ethanol
from corn production yields 24% more energy than it takes to produce. In 2002,
the report was updated and
the overall number was increased to 34% (see 8/12/02).
Pimentel did update some of his numbers and talked to a source at Delta-
T, a builder of ethanol plants,
Shapouri acknowledged. However, some of the data he uses is from 1979, he
includes energy for labor
(such as the energy the tractor uses to farm the land), as well as energy for
steel, cement or other materials
used to construct the ethanol plant in his calculations, Shapouri added.
Additionally, the amount of energy for nitrogen fertilizer and phosphorus
is an important factor in
calculating energy balance. While USDA got its figures from the Fertilizer
Institute, Pimentel got his from
the Food and Agriculture Administration of the United Nations, which covers
world estimates and not just
the U.S., Shapouri said. Therefore, his numbers do not accurately reflect the
U.S. ethanol production
industry, he added.
But it seems Shapouri wasn't the only one criticizing studies. Pimentel,
unlike in previous studies, took
a more offensive position, devoting four paragraphs to discrediting USDA's
latest study. “Unfortunately,
some major energy inputs in corn production were either out-of-date or omitted"
in the USDA study, he
said. “Information on corn input production data were from 1991 and production
data covered only nine
states instead of all 50 states,” he added, noting the increased energy required
to produce hybrid corn,
which is now planted exclusively in the U.S., was not included.
In response, Shapouri said they only included the major corn-producing
states, since those nine states
provide almost all of the corn used in the country. He also questioned the
timing of Pimentel's study, right
after the Senate passed its energy bill (which includes a renewables mandate, an
RFS, that will mainly be
made up by using ethanol) and left for its August recess.
Pimentel also took a swipe at the RFS, noting that doubling or tripling
the amount of ethanol produced
would increase the cost to taxpayers by 2-4 times the current $1.4 billion/yr
incentive cost. “With current
budget deficits, is this increasing ethanol production a sound policy?” he
asked.
The often-studied issue of ethanol's energy balance has heated up over
the past several years. It appears
only Pimentel and researchers at the University of California-Berkeley agree
that it takes more energy to
produce ethanol than it saves (see OFN, 6/23/03), whereas USDA, EIA, scientists
at Michigan State
University and Argonne National Laboratory have concluded ethanol has a positive
net energy balance.
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