Study: Fuels from corn waste not better than gas


WASHINGTON (AP) — Biofuels made from the leftovers of
harvested corn plants are worse than gasoline for global warming in the
short term, a study shows, challenging the Obama administration’s
conclusions that they are a much cleaner oil alternative and will help
combat climate change.
A $500,000 study paid for by the federal
government and released Sunday in the peer-reviewed journal Nature
Climate Change concludes that biofuels made with corn residue release 7
percent more greenhouse gases in the early years compared with
conventional gasoline.
While biofuels are better in the long run,
the study says they won’t meet a standard set in a 2007 energy law to
qualify as renewable fuel.
The conclusions deal a blow to what are
known as cellulosic biofuels, which have received more than a billion
dollars in federal support but have struggled to meet volume targets
mandated by law. About half of the initial market in cellulosics is
expected to be derived from corn residue.
The biofuel industry and
administration officials immediately criticized the research as flawed.
They said it was too simplistic in its analysis of carbon loss from
soil, which can vary over a single field, and vastly overestimated how
much residue farmers actually would remove once the market gets
"The core analysis depicts an extreme scenario that no
responsible farmer or business would ever employ because it would ruin
both the land and the long-term supply of feedstock. It makes no
agronomic or business sense," said Jan Koninckx, global business
director for biorefineries at DuPont.
Later this year the company
is scheduled to finish a $200 million-plus facility in Nevada, Iowa,
that will produce 30 million gallons of cellulosic ethanol using corn
residue from nearby farms. An assessment paid for by DuPont said that
the ethanol it will produce there could be more than 100 percent better
than gasoline in terms of greenhouse gas emissions.
The research
is among the first to attempt to quantify, over 12 Corn Belt states, how
much carbon is lost to the atmosphere when the stalks, leaves and cobs
that make up residue are removed and used to make biofuel, instead of
left to naturally replenish the soil with carbon. The study found that
regardless of how much corn residue is taken off the field, the process
contributes to global warming.
"I knew this research would be
contentious," said Adam Liska, the lead author and an assistant
professor of biological systems engineering at the University of
Nebraska-Lincoln. "I’m amazed it has not come out more solidly until
The Environmental Protection Agency’s own analysis, which
assumed about half of corn residue would be removed from fields, found
that fuel made from corn residue, also known as stover, would meet the
standard in the energy law. That standard requires cellulosic biofuels
to release 60 percent less carbon pollution than gasoline.
biofuels that don’t meet that threshold could be almost impossible to
make and sell. Producers wouldn’t earn the $1 per gallon subsidy they
need to make these expensive fuels and still make a profit. Refiners
would shun the fuels because they wouldn’t meet their legal obligation
to use minimum amounts of next-generation biofuels.
spokeswoman Liz Purchia said in a statement that the study "does not
provide useful information relevant to the life cycle greenhouse gas
emissions from corn stover ethanol."
But an AP investigation last
year found that the EPA’s analysis of corn-based ethanol failed to
predict the environmental consequences accurately.
The departments
of Agriculture and Energy have initiated programs with farmers to make
sure residue is harvested sustainably. For instance, farmers will not
receive any federal assistance for conservation programs if too much
corn residue is removed.
A peer-reviewed study performed at the
Energy Department’s Argonne National Laboratory in 2012 found that
biofuels made with corn residue were 95 percent better than gasoline in
greenhouse gas emissions. That study assumed some of the residue
harvested would replace power produced from coal, reducing greenhouse
gas emissions, but it’s unclear whether future biorefineries would do
Liska agrees that using some of the residue to make
electricity, or planting cover crops, would reduce carbon emissions. But
he did not include those in his computer simulation.
Still, corn
residue is likely to be a big source early on for cellulosic biofuels,
which have struggled to reach commercial scale. Last year, for the fifth
time, the EPA proposed reducing the amount required by law. It set a
target of 17 million gallons for 2014. The law envisioned 1.75 billion
gallons being produced this year.
"The study says it will be very
hard to make a biofuel that has a better greenhouse gas impact than
gasoline using corn residue," which puts it in the same boat as
corn-based ethanol, said David Tilman, a professor at the University of
Minnesota who has done research on biofuels’ emissions from the farm to
the tailpipe.
Tilman said it was the best study on the issue he has seen so far.
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