biofuels

With scientists bickering over the benefits or disadvantages of biofuels production, it's hard to know who to believe.

Corn ethanol, already under fire for its role in food price increases, received another blow from the scientific community when a study published in Feb. 8 issue of Science magazine showed that current production methods of biofuels may do more harm for the environment than good.

They could release significantly more carbon into the atmosphere than gasoline production, adding to greenhouse gases and global warming, the study concluded.

Such studies "may misguide policy fuel development," wrote Michael Wang, a researcher at Argonne National Laboratory, in a recent letter sent to the editors of Science.

Wang developed the software analysis tool, known as the GREET model, used in the study reported in Science. He wrote that the study incorporated a few key assumptions that, taken together, exaggerate the greenhouse gas impact of biofuel production.

Two contradictory studies reported that the production of cellulosic ethanol from switchgrass resulted in a net increase in greenhouse gases of 50 percent or reduced greenhouse gases by 94 percent compared with gasoline production.

Wang, who has conducted extensive fuel production analyses of his own, noted in his letter that the recent study used outdated corn yields and assumed that crops used in biofuel production would replace cropland used to grow corn and other food crops, which is not necessarily the case.

The study "modeled a case in which U.S. corn ethanol production increased from 15 billion gallons a year to 30 billion gallons a year by 2015," Wang wrote. However, Congress capped ethanol production at 15 billion gallons a year by 2015 in the 2007 Energy Independence and Security Act "to help prevent dramatic land use changes."

The 2007 energy legislation, signed by President Bush in December, mandates that 36 billion gallons per year of ethanol be a part of the American fuel system by 2022. Almost two-thirds of this ethanol, however, must be derived from non-food sources, necessitating the production of so-called next generation ethanol such as cellulosic ethanol.

Next generation biofuels could be made from plants such as switchgrass and jatropha that grow on land inhospitable to food crops.

Cellulosic ethanol technology developed by Warrenville-based Coskata Inc. in partnership with General Motors Corp. could turn municipal waste, crop residues and non-food crops into low-cost cellulosic ethanol.

Go to an interactive chart comparing the results of studies analyzing the greenhouse gas impact of biofuels production

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The toughest challenge to overcome before switchgrass and other biomass crops can provide cheap, renewable fuel is convincing farmers to grow the crops in the first place.

Recent evidence shows that producing ehtanol from switchgrass yields five times more energy than producing it from corn, though commercial production plants still need to be developed. But all these considerations are moot if farmers don't want to plant the crop.

"It's gotta be competitive with corn or soybean production, just like any crop" said John Hawkins, a spokesman for the Illinois Farm Bureau.

This would be difficult in the highly productive soils of Northern and Central Illinois, where crop yields are greater, Hawkins said, but he saw potential for switchgrass and other biomass crops in the more marginal farmland in Southern Illinois.

"Switchgrass is probably going to become a crop down the road, but it's probably going to be a niche crop," Hawkins said. "It's just that we haven't gotten to that point."

Energy legislation signed into law by President Bush in December mandates that 36 billions gallons of renewable fuels be a part of America's fuel supply by 2022. At least 21 billion gallons must come from so-called advanced renewable fuels, which doesn't include fuels made from food crops such as corn.

Virtually no advanced renewable fuels currently contribute to the nation's fuel supply. Cellulosic ethanol is the most likely candidate to fulfill the mandate.

This won't happen, though, until biomass crops like switchgrass and miscanthus-another grass that can be used to make cellulosic ethanol-can compete with cash crops such as corn and soybeans in terms of profitability, said Anne Heinze Silvis, a researcher at the University of Illinois at Urbana-Champaign.

Silvis surveyed farmers in Illinois and conducted focus groups to determine what factors they would weigh when deciding whether to plant a biomass crop. She learned that market viability is one of the primary concerns when it comes to making the decision to switch from one crop to another. And there's no market history for pricing switchgrass.

Still, Illinois farmers are receptive to these new type of crops if they have a competitive market, Silvis said.

"They're thinking: 'Energy crops, local foods. If I had a market, I would produce for that market,'" she said.

General Motors Corp. announced Sunday it was partnering with Warrenville-based Coskata Inc., which plans to have the capability to produce 100 million gallons of cellulosic ethanol per year by 2010, indicating that large companies see the fuel as a viable and potentially lucrative possibility.

That is the kind of investment that needs to be made if cellulosic ethanol is to become successful, said Hans Blaschek, director of the Center for Advanced BioEnergy Research at the University of Illinois at Urbana-Champaign.

A concerted effort involving government, researchers, farmers and corporations is necessary to figure out the logistics and science to make large-scale production of cellulosic ethanol a reality, Blaschek said.

"Most people really don't know how this is going to work," Blaschek said. He thought it may be 10 years before large-scale cellulosic ethanol production becomes commercially viable.

Ethanol made from switchgrass yields more than five times the energy required to produce it, according to a study conducted by scientists at the University of Nebraska and released last week in the Proceedings of the National Academies of Science. There could even be enough energy leftover from byproducts to run the processing plant.

This is a dramatic improvement over corn-based ethanol-the primary source of liquid renewable fuel in the country. Corn only yields about as much energy as is used to produce it.

Cellulosic ethanol derives its energy from sugars stored in the cell walls of plants. Grasses, discarded corn stalks, wood chips and agricultural waste materials are all potential sources of cellulosic ethanol.

The University of Nebraska study demonstrated another benefit - that over time, switchgrass becomes a neutral or even negative greenhouse gas producer. It absorbs as much or more carbon dioxide than used to grow the crop.

The study-performed on farms throughout Nebraska, South Dakota and North Dakota-was the first to examine the effects of cultivating switchgrass in large fields, rather than in the small test plots less than five meters squared used in previous studies.