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Analysis: Ethanol's Potential: Looking Beyond Corn

From: Environment News Service <>
Analysis: Ethanol's Potential: Looking Beyond Corn

(note: here is a graph from UC Berkeley showing how ethanol made from corn takes up six times as much energy as it produces.)

By Danielle Murray

WASHINGTON, DC, July 1, 2005 (ENS) - At the fuel pumps in São Paulo,
customers have a choice: gas or alcohol? Since the mid-1970s, Brazil has
worked to replace imported gasoline with ethanol, an alcohol distilled from
locally grown sugarcane. Today ethanol accounts for 40 percent of the fuel
sold in Brazil.

Ethanol can be produced from a wide variety of plant-based feedstocks, most
commonly grain or sugar crops. It is then blended with gasoline as an
oxygenate or fuel extender for use in gasoline vehicles, or it can be used
alone in "flexible-fuel vehicles" that run on any blend of ethanol and

Brazil led world ethanol production in 2004, distilling four billion
gallons (15 billion liters). The United States is rapidly catching up,
however, producing 3.5 billion gallons last year, almost exclusively from
corn. China's wheat and corn rich provinces produced nearly one billion
gallons of ethanol, and India turned out 500 million gallons made from
sugarcane. France, the front-runner in the European Union¹s attempt to boost
ethanol use, produced over 200 million gallons from sugar beets and wheat.

In all, the world produced enough ethanol to displace roughly two percent
of total gasoline consumption.

Fuel at this E-85 station is 85 percent ethanol and 15 percent gasoline.
(Photo by Warren Gretz courtesy NREL)
Efforts to substitute alternative fuels for petroleum are gaining attention
in a world threatened by climate change, rural economic decline, and
instability in major oil-producing countries.

Biofuel crops take in carbon dioxide from the atmosphere while they are
growing, offsetting the greenhouse gases released when the fuel is
subsequently burned. Replacing petroleum with biofuel can reduce air
pollution, including emissions of fine particulates and carbon monoxide.

Biofuel production also can improve rural economies by creating new jobs
and raising farm incomes. As a locally produced, renewable fuel, ethanol has
the potential to diversify energy portfolios, lower dependence on foreign
oil, and improve trade balances in oil-importing nations.

Although ethanol¹s popularity is growing, today¹s inefficient production
methods and conversion technologies mean that this fuel will only produce
modest environmental and economic benefits and could impinge on
international food security.

The largest obstacle to biofuel production is land availability. Expanding
cropland for energy production will likely worsen the already intense
competition for land between agriculture, forests, and urban sprawl. With
temperatures rising and water tables falling worldwide, global food supply
and demand are precariously balanced.

World grain reserves are near all-time lows, and there is little idle
cropland to be brought back into cultivation. Shifting food crops to fuel
production could further tighten food supplies and raise prices, pitting
affluent automobile owners against low-income food consumers.

Placing greater emphasis on land efficiency yield per acre corn has broad political support as a feedstock in the United States, it is
one of the least efficient sources of ethanol. For example, ethanol yields
per acre for French sugar beets and Brazilian sugarcane are roughly double
those for American corn.

Also important is the amount of energy used to produce ethanol. Growing,
transporting, and distilling corn to make a gallon of ethanol uses almost as
much energy as is contained in the ethanol itself. Sugar beets are a better
source, producing nearly two units of energy for every unit used in

This Hawaiian sugar cane can be used to produce ethanol. (Photo Warren
Gretz courtesy NREL)
Sugarcane, though, is by far the most efficient of the current feedstocks <
yielding eight times as much energy as is needed to produce the ethanol.
Given their positive energy balances and higher yields, it makes more sense
to produce ethanol from sugar crops than from grains.

Ethanol could quickly take off in sugarcane-producing tropical countries,
which have the advantage of year-round growing seasons, large labor
supplies, and low production costs. As fuel demand rises in these developing
nations, biofuel production could check oil imports while bolstering rural

Brazil, for example, could produce enough ethanol to meet total domestic
fuel demand by increasing the area used to grow sugarcane for alcohol from
6.6 million acres to 13.8 million acres (5.6 million hectares) or by
shifting all current sugarcane acreage to ethanol production. Unfortunately,
new fields may cut further into already shrinking rainforests, making them a
serious environmental liability.

If ethanol is to become a major part of the world fuel supply without
competing with food and forests, its primary source will not be grains or
even sugar crops; it will be more abundant and land efficient cellulosic
feedstocks, such as agricultural and forest residues, grasses, and
fast-growing trees.

Promising new technologies are being developed that use enzymes to break
down cellulose and release the plants¹ sugars for fermentation into ethanol.
A demonstration plant using this technology opened in Canada last year, and
large-scale production is expected to be commercially viable by 2015.

Gathering corn stalks for ethanol production makes use of residues that
once were burned. (Photo Warren Gretz courtesy NREL)
Agricultural residues, such as corn stalks, wheat straw, and rice stalks,
are normally left on the field, plowed under, or burned. Collecting just a
third of these for biofuel production would allow farmers to reap a sort of
second harvest, increasing farm income while leaving enough organic matter
to maintain soil health and prevent erosion.

The agricultural residues that could be harvested sustainably in the United
States today, for example, could yield 14.5 billion gallons of ethanol <
four times the current output
"Energy crops," such as hardy grasses and fast growing trees, have higher
ethanol yields and better energy balances than conventional starch crops.

One likely candidate is switchgrass, a tall perennial grass used by farmers
to protect land from erosion. It requires minimal irrigation, fertilizer, or
herbicides but yields 2-3 times more ethanol per acre than corn does. Such
crops could potentially be harvested on marginal land, avoiding the
conversion of healthy cropland or forests to energy-crop production.

Still, with world energy demands rising, biofuels will meet only a fraction
of fuel needs unless there are substantial improvements in vehicle fuel

Fortunately, the technologies required are available and affordable.
Shifting vehicle production to gas-electric hybrids, like those on the
market today, and reducing weight and drag would decrease fuel use several

Adding an extra battery and plug-in capability to hybrid vehicles would
allow short trips to be made using only electric power ­ preferably produced
from wind ­ decreasing fuel demand to levels that could be met with ethanol

Increasing the role of ethanol in meeting fuel demand will require ongoing
research and development to improve biomass-ethanol conversion technologies,
along with consistent legislative support for biofuel production and greater
fuel efficiency in the automotive industry.

Shifting government energy subsidies, such as from oil exploration to
biofuel development, is a clear choice as new oil fields prove increasingly
elusive. With improved vehicle fuel economy and the use of more efficient
cellulosic feedstocks, biofuel has the potential to supply a substantial
share of the world¹s automotive fuel.

For more examples of ethanol production by country, see data at:

{Published in cooperation with the Earth Policy Institute, online at:}

Questions or Comments: editor at