EarthTalk: I thought that putting ethanol in
our gas tanks was going help fight climate change, but lately
I’ve heard reports to the contrary. Can you enlighten?
—Bill B., Hershey, PA
federal government’s push to increase production
of corn-derived ethanol as a gasoline additive since
2007 has actually expanded our national carbon footprint
and contributed to a range of other problems.
credit: Michael Cote
and similar “biofuels” made from corn and other
crops seem like a good idea given their potential for reducing
our carbon outputs as well as our reliance on fossil fuels.
But recent research has shown that the federal government’s
push to up production of corn-derived ethanol as a gasoline
additive since 2007 has actually expanded our national carbon
footprint and contributed to a range of other problems.
corn producers started ramping up ethanol production in
2007 as a result of President George W. Bush’s Renewable
Fuels Standard (RFS), which mandated an increase in the
volume of renewable fuel to be blended into transportation
fuel from nine billion gallons in 2008 to 36 billion by
2022. Ethanol now makes up 10 percent of the gasoline available
at filling stations.
environmentalists now say that the promise of ethanol has
turned out to be too good to be true. For one, there is
the issue of net energy produced. According to Cornell University
ecologist David Pimentel, growing and processing corn into
a gallon of ethanol requires 131,000 BTUs of energy, but
the resulting ethanol contains only 77,000 BTUs. And since
fossil-fuel-powered equipment is used to plant, harvest,
process and distribute ethanol, the numbers only get worse.
non-profit Environmental Working Group (EWG) warns that
continued production of corn ethanol is not only “worse
for the climate than gasoline” but also bad for farmers,
the land and consumers: “It is now clear that the
federal corn ethanol mandate has driven up food prices,
strained agricultural markets, increased competition for
arable land and promoted conversion of uncultivated land
to grow crops.”
the group reports that previous estimates “dramatically
underestimated corn ethanol’s greenhouse gas emissions
by failing to account for changes in land use,” citing
a 2012 study documenting the conversion of eight million
acres of Midwestern grassland and wetlands to corn fields
for ethanol between 2008 and 2011. “These land use
changes resulted in annual emissions of 85 million to 236
million metric tons of greenhouse gases,” says EWG.
“In light of these emissions, many scientists now
question the environmental benefit of so-called biofuels
produced by converting food crops.”
the potential negative impacts of so-much corn-based ethanol,
the U.S. Environmental Protection Agency is reportedly weighing
a proposal to cut the amount currently required by law to
be blended into gasoline by 1.39 billion gallons. If the
federal government decides to do this, it could lower U.S.
carbon emissions by some three million tons—equivalent
to taking 580,000 cars off the roads for a year.
researchers are trying to develop greener forms of ethanol,
but none are ready for market yet. “The lifecycle
emissions of ethanol ‘from seed to tailpipe’
depend on how the ethanol is made and what it is made from,”
reports the Union of Concerned Scientists (UCS). The best
ethanol, they say, can produce as much as 90 percent fewer
lifecycle emissions than gasoline, but the worst can produce
much more. So there still may be room for ethanol in our
energy future, but not if we keep doing it the way we are
Fuel Standard; David
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