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Leftovers from Harvest are Potential Fuel Source

October 16, 2006


ERIKA SCHULTZ / THE SEATTLE TIMES
Steve Fransen, a Washington State University forage agronomist at Prosser,
Benton County, harvests a plot of switch grass earlier this year. The
harvested grass will be analyzed this winter to gauge its potential ethanol
yield.


Leftovers from harvest are potential fuel source

By Hal Bernton
Seattle Times staff reporter

MEAD, Neb. � Duck beneath the green canopy of midsummer corn and you find
the faded remains of last year's harvest. The ground here is littered with
a patchwork of withered husks, gnarled stalks and hunks of cob spread out
over sandy soil.

Such leftovers may one day be a second farm crop, shipped off to a new
generation of distilleries able to turn cellulose � the tough fibers that
form the inner walls of most plants � into ethanol fuel for cars.

The biotechnology for a potential cellulose gold rush has been decades in
development, with President Bush, in January's State of the Union address,
saying that federal research dollars would try to make the process
"practical and competitive" within six years.

For an America now hooked on imported oil, cellulose offers an intriguing
vision for the future by broadening an alternative fuel industry that now
relies almost exclusively on corn kernels.

Cellulose is found in corn husks, wheat straw, trees, and fast-growing
perennial crops such as switch grass, which is being grown on test plots in
Nebraska, Washington and other states. A federal Energy Department study
concluded that cellulose plant materials could help renewables supply 30
percent of the nation's liquid fuel needs by 2030.

But tapping farm fields to produce both energy and food crops also creates
new risks for agriculture and the environment.

Some cellulose materials � such as the corn harvest leftovers � already
play an important role when returned to the soil. As they decay, they help
fight erosion, improve the organic matter that is key to soil quality, and
slow the release of carbon dioxide, a greenhouse gas that contributes to
global warming.

Federal studies at the University of Nebraska's research center in Mead
indicate that on some lands all the corn residues should be left.

On others, only a portion should be removed, and researchers here are
scrambling to develop new guidelines they hope farmers will respect.

"These crop residues are not being wasted. They are being used quite
wisely," said Wally Wilhelm, a federal plant physiologist who has spent
much of the past quarter-century studying how crop residues return organic
materials to the soil. "To wholeheartedly say that every wheat straw and
cornstalk that is out there in November is now fair game � that is not
the way we need to do it."

Researchers in Washington say that some wheat straw also should be returned
to the soil.

"We have some high-rainfall zones that produce an abundance of wheat straw,
and you could remove some without damaging soil fertility," said Rick
Koenig, a Washington State University researcher. "But in a lot of our
drier areas, it's best to return to it all to the soil."

Nature points the way

The jungle rot that plagued GIs during World War II gave researchers early
clues on how to turn cellulose into fuel.

Cellulose is formed by long chains of glucose molecules, which create very
strong bonds that are hard to break down. But the cellulose in canvas
tents, cotton uniforms and other World War II gear didn't hold up under the
assault of potent molds that the troops encountered in New Guinea and other
tropical islands.

Army scientists sought to find ways to combat jungle rot, and noted that
some of the most potent molds secreted an enzyme that rapidly broke down
cellulose into glucose sugars. These sugars could be fermented into
ethanol, opening the door in the post-war era for researchers to pursue
cellulose-to-fuel technology.

But it has been difficult to reliably mass-produce the enzymes, then
profitably convert cellulose into ethanol. A series of cellulose plants
proposed over the decades were never built.

Given current technology, federal officials estimate production costs at
about $2.25 a gallon � more than double the production costs of corn
ethanol from starch, according to Andy Aden, a cellulose specialist with
the National Renewable Energy Laboratory in Golden, Colo.

Still, the federal government and corporations have stepped up research
efforts to turn cellulose into fuel.

This summer, Xethanol, a publicly traded company, announced plans to build
a 50-million-gallon-a-year cellulose ethanol plant in Georgia that would be
fed by the forestry industry.

Iogen, a Canadian company that operates a small pilot project in Montreal,
is considering construction of a wheat-straw plant in Idaho.

In the Midwest, major ethanol producers that process corn kernels are
monitoring � and, in some cases, investing in � this research, hoping
to eventually have the capacity to process cellulose pulled from the
region's vast fields of corn.

"There is an awful lot of good thinking about how do we find the silver
bullet," said Marty Lyons, a senior vice president for Archer Daniels
Midland, the nation's largest corn-ethanol producer and an investor in
cellulose research.

If cellulose technology takes hold, ethanol yields from a corn field would
receive a substantial boost. Fields that now produce enough corn kernels to
yield about 400 gallons of ethanol per acre could produce as much as 280
additional gallons of ethanol per acre from the cobs, leaves and other
cellulose material.

This might prompt some Midwest farmers to expand corn acreage, pushing into
marginal lands more prone to erosion and leaching fertilizers and
pesticides into waterways.

The government has sought to take such lands out of cultivation, paying
farms to turn the acreage into conservation tracts typically planted in
grasses that help hold the soil, provide cover for wildlife and protect the
waterways. Currently, some 36 million acres of farmland are set aside in
these reserves, with farmers receiving $1.76 billion annually not to grow
crops on these tracts.

Rather than putting corn back into these lands, researchers have proposed
planting some of them in switch grass, a native to the Midwest and one of
four major prairie grass species that fed the vast herds of buffalo.

The hardy perennial can be grown in the same field for eight to 15 years in
a row and provide cover for birds. The crop requires far less pesticides
and fuel-intensive tractor work than corn. Its roots may extend some 10
feet deep, helping hold the soil in place. They also store large amounts of
carbon, and thus help slow the release of carbon dioxide.

As an energy crop, the grass does have drawbacks. The huge bulk of the
bales makes it difficult and expensive to transport over long distances to
a distillery. Also, it is uncertain how well they would survive long
periods of storage

But cellulose yields in test plots are impressive, with switch-grass tracts
harvested once or twice a year estimated to produce from 200 to as much as
1,000 gallons of ethanol per acre.

In the Midwest, switch grass already is grown on some conservation-reserve
lands.

Fields too dry

In Washington, it would likely have a smaller niche because most of the
conservation-reserve lands are too dry in the summer to support switch
grass, said Steve Fransen, a Washington State University forage agronomist
at Prosser, Benton County.

The prime irrigated lands of the Yakima basin � already claimed by
orchards, vineyards, hops and other high-value crops � could also grow
switch grass if the payoff were high enough for farmers.

On test plots at the Prosser research station, Fransen and other
researchers are experimenting with different varieties of switch grass to
learn more about yields.

Fransen said a fresh summer planting of switch grass doesn't look like much
� just a struggling patch of sod.

"It's putting all of its energy into its roots and crown system," Fransen
said. "Then the next year, it just goes into this explosion."

In some of the research plots, the grass has grown more than 6 feet tall.
Meanwhile, the roots spread into a thick underground mat that reaches as
much as 10 feet deep to soak up water and nutrients.

Switch grass could eventually be part of a broader mix of new ethanol crops
that could include wheat straw, as well as fast-growing poplars, which
already are grown in Eastern Washington by the timber industry. The
emergence of such crops will depend on continued development of the
cellulose-to-ethanol technology. And on whether oil prices stay high.

Federal officials are convinced that cellulose production costs can be cut
to about $1.07 per gallon � roughly half their current levels � by 2012.

"It's an aggressive track, but doable," said Aden, the cellulose specialist
at the National Renewable Energy Laboratory.

Hal Bernton: 206-464-2581 or hbernton@seattletimes.com

Copyright � 2006 The Seattle Times Company