Federal help for cellulosic ethanol

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Prairie grasses like these may be used someday to make cellulosic ethanol.
MPR Photo/Mark Steil

Ethanol has become a major component of the nation's alternative energy drive and that makes it's main ingredient a source of intense debate. The basic technology of distilling corn into alcohol has been around for centuries. It was a natural choice for the ethanol industry when it started more than 20 years ago. Corn has limitations, though.

University of Minnesota ecology professor David Tilman says there may not be enough corn to feed humans, livestock and fuel refineries.

"The estimates are within 40 or 50 years we're going to need twice as much food on the world and twice as much energy as we have now," says Tilman. "And we don't have twice as much land to use. We don't have that much land left in the world now that we can convert to agriculture."

Tilman studied native prairie plants as a substitute for corn in making ethanol. He found that they can provide plenty of cellulose to make the fuel. Other researchers have reached the same conclusion. The problem is technology. No one is sure if cellulose to ethanol can be done profitably. To test the concept, the federal government is ready to hand out more than $150 million in grants. The money will help several company's build the nation's first cellulose ethanol plants.

"We're committed to the development of cellulose technology."

The Department of Energy's John Mizroch says the money should be awarded early next year.

"Our goal at the department is to try to promote its being produced on a commercial scale cost effectively," says Mizroch. "And we deem that cost effective at or around $1.07 a gallon."

That would be in roughly the same range as what it costs today to make ethanol from corn. One of the companies hoping for some of that federal money is Broin Companies of Sioux Falls. It currently manages 19 ethanol production plants across the nation.

Broin's Mike Lockrem says the company wants to add a cellulose plant when it expands its Emmetsburg, Iowa corn ethanol facility.

"We're committed to the development of cellulose technology," says Lockrem. "But our project in Emmetsburg this is a vital part of that, that Department of Energy funding."

Lockrem says the cellulose for the operation will come from corn stover. Stover is basically the entire corn plant, minus the ear. He says stover makes sense since the company is already tied in to a network of farmers who can easily meet the company's cellulose needs.

University of Minnesota researcher David Tilman has a different sort of plant material in mind for cellulosic ethanol. He studied a mix of 16 prairie grasses and legumes.

"We find we actually get more net useable energy coming from an acre of prairie on this land than we do from an acre of corn that is used to make ethanol," says Tilman. "And that really surprised us because corn's a very productive plant."

Tilman says the main reason prairie plants beat corn is because they take far less energy to grow. Corn requires lots of fuel for tractors and natural gas to make fertilizers. The prairie plants are like lawn grass. Once they're established, they come up each year on their own. Tilman says another benefit of the prairie plants is that they do fine on marginal land, leaving the best acres for food production. The debate over which basic ethanol ingredient works best likely will take years to settle. Cellulose is promising, and energy companies are busy trying to find out if they can make the fuel and money at the same time.