Can Energy Intensive Corn & Ethanol Really Become Part of the Solution to the Energy Crisis?

http://www.nytimes.com/2006/02/07/science/07fuel.html?_r=1&oref=slogin

By Matthew L. Wald, The New York Times, February 7, 2006

February 7, 2006

Corn Power Put to the Test
By MATTHEW L. WALD

AMES, Iowa < The endless fields of corn in the Midwest can be distilled into
endless gallons of ethanol, a clean-burning, high-octane fuel that could end
any worldwide oil shortage, reduce emissions that cause global warming, and
free the United States from dependence on foreign energy.

There is only one catch: Turning corn into ethanol takes energy. For every
gallon that an ethanol manufacturing plant produces, it uses the equivalent
of almost two-fifths of a gallon of fuel (usually natural gas), and that
does not count the fuel needed to make fertilizer for the corn, run the farm
machinery or truck the ethanol to market.

The use of all that fossil fuel to make ethanol substantially reduces its
value as an alternative source of energy. Not that ethanol is useless. For
one thing, it is far easier than natural gas to use in motor vehicles.

Production is expected to hit five billion gallons this year, equal to more
than 3 percent of gasoline supplies, and more ethanol distilleries are being
built. [In his State of the Union message, President Bush called for
research on "cutting-edge methods of producing ethanol."]

But if ethanol is to realize its potential, its proponents recognize that
they will have to develop new ways to make it without using so much natural
gas < or coal, as some distilleries are doing to save money.

"In this industry, you can't take a parochial view of your business," said
William A. Lee, general manager of Chippewa Valley Ethanol, in Benson,
Minn., and former chairman of the Renewable Fuels Association, an ethanol
trade group. "We have to be headed to a more sustainable future." Engineers
are trying a variety of methods. Here are several of the most promising.

Get Help From the Cow

Some companies are building ethanol plants next to cattle feeding
operations, so that corn can go through the ethanol distillery, and then
residues from the operation < basically corn, minus the starch < can go
straight to the cattle as feed.

The corn passes through the cow, and the manure may come back to the plant
and go into a contraption called an anaerobic digester, which mimics the
conditions in a cow's stomach so that bacteria can produce methane, a
component of natural gas.

Get Closer to the Cow

The corn residues, called distillers grains, can be exposed to
high-temperature steam, to turn their carbohydrates into hydrocarbons. If
the distillers grains are used as cattle feed, the resulting manure can also
be exposed to steam to produce hydrocarbons.

Ethanol takes energy to make because it requires a lot of steam. Typically,
the steam is used to blast cornstarch and water into a smooth mixture,
keeping the mixture at an ideal temperature for enzymes to break down the
valuable chemicals in the starch and for yeast to turn corn sugars into
alcohol. Then the mixture is heated to distill off the alcohol, and the
remaining distillers grains are usually dried to extend their shelf life
until they can be eaten by cattle.

Some ethanol producers skip the drying, if there are enough cattle nearby
that the grains can be eaten promptly. In Sioux Center, Iowa, at the
Siouxland Energy and Livestock Cooperative, local farmers opened a plant in
2001 that is adjacent to a 10,000-head feedlot.

By not drying the grains, Siouxland has reduced its natural-gas consumption
to 24,000 B.T.U. per gallon of ethanol < meaning that the natural gas it
uses has an energy value less than one-third that of the ethanol it makes,
creating 85,000 B.T.U. a gallon when burned. (This calculation does not
count the electricity the plant uses, or the diesel fuel used to haul the
ethanol to a filling station.)

Make a New Kind of Gas

At the Iowa Energy Center, a state-financed lab here amid the cornfields
near the Iowa State University campus, engineers are experimenting with
another technique.

A cluster of steam pipes, gleaming steel tanks, augers and hoppers,
assembled by a start-up engineering firm called Frontline Bioenergy, is
replacing natural gas with another gas on a small scale, for now.

The new gas is made from the part of the corn plant that is not the kernel,
chopped into pieces half an inch long and dumped into a tank with steam and
a limited amount of air.

In a process called partial oxidation, the steam breaks apart the plant's
carbohydrates into two gases: elemental hydrogen and carbon monoxide. Both
burn nicely as a substitute for natural gas.

About 90 percent of the material turns to gas; some of the remainder is
minerals that can be sold for other uses. The process consumes natural gas
to get started, but after that, it burns the gas it makes to sustain itself.
"It's a renewable substitute for natural gas," said Norman Reese, general
manager of Frontline Bioenergy.

The corn parts that the process uses, called stover, are left in the field.
They could be burned directly but would be much dirtier that way.

But Back to the Cow
A variety of materials can be turned into gas, including manure.

"Manure is just partly processed biomass," said Jerod Smeenk, engineering
manager at Frontline Bioenergy.

Chippewa Valley Ethanol, the Minnesota company, plans to have a pilot-scale
plant running in about a year, using distillers grains. The choice is not
ideal, because the grains are not waste; they have a market value as cattle
feed. But it is a low-risk choice for Chippewa, which can invest in the
equipment needed to gather stover if the gasifier works as promised.

Companies like Chippewa may promote their aspiration to protect the
environment, but they are also driven by price. When the ethanol industry
started 20 years ago, it took twice as much natural gas to make a gallon of
ethanol as it does now, said Mr. Lee, the general manager. But gas was much
cheaper then.

Right now, Chippewa is paying as much as $12 per million B.T.U. for natural
gas, compared with $2 in the mid-1980's, and Mr. Lee said gasification
"makes economic sense" when gas costs $10 or more per million B.T.U.
At Frontline, John Reardon, the research and development manager, said of
the gasification project: "It's just a step. But our whole economy is based
on fossil energy, and we have to make a step somewhere."

Copyright 2006The New York Times Company