http://www.startribune.com/535/story/861837.html
Grass beats corn in ethanol study Corn may be less potent than a mix of prairie grasses in the making of the fuel additive, University of Minnesota researchers concluded. Mike Meyers, Star Tribune December 07, 2006 World demand for fuel and food is projected to double in the next 50 years. Now, researchers at the University of Minnesota have concluded that corn may not be up to the task of filling both stomachs and gas tanks. "Unless we produce food and biofuel in an efficient manner, they will be directly competing with each other," said David Tilman, regents professor of ecology at the University of Minnesota. "We will have high prices for both." University researchers, led by Tilman, think they've found a solution -- supply the facilities that make ethanol with a diverse mixture of prairie grasses instead of corn. The grasses not only can produce more net energy per acre than corn but they also act as a sponge for greenhouse gases before being harvested, soaking them out of the air and into their roots and surrounding soil, the researchers found. The last trait could prove an economic bonus for farmers if businesses one day are able to cash in "credits" for removing greenhouse gases from the air, as many predict. Clean air credits already are traded in Europe. Nearly 100 ethanol plants consuming corn have sprung up across the country. A director of the Minnesota Corn Growers Association has warned that supplanting corn with grasses would be a complex, costly task that could take years. But in an interview, Tilman contended that prairie grasses could represent a new cheap-to-produce cash crop that would be more of an opportunity than threat to farmers. In a cover story published today in Science magazine, the researchers reported that a field planted with a medley of prairie grasses and flowering plants packed more than triple the energy of single-variety grasses. The study also estimated that mixed prairie grasses grown on marginal farmland would yield 51 percent more energy per acre than corn cultivated on fertile land. The prairie grasses were grown on depleted land without fertilizers and pesticides commonly used for corn. The grasses require almost no maintenance, so less gasoline and diesel fuel would be burned tending to fields. Harvesting and processing a hectare (about 2.5 acres) of grasslands produces about three-tenths of a metric ton of carbon dioxide, the researchers calculated. But in the first 10 years, the grasses absorb 4.4 metric tons of carbon dioxide. In other words, the prairie grasses absorb about 14 times more greenhouse gas than is released in producing grass-based fuel. Tilman led researchers studying grass crops planted at the Cedar Creek Natural History Area in central Minnesota. President Bush has touted research into making ethanol from switchgrass. But the researchers found that a single species of grass is far less promising as material for ethanol production than is a blend of prairie grasses. They studied 16 varieties. "Switchgrass is very productive when it's grown like corn, in fertile soil with lots of fertilizer, pesticide and energy inputs, but this approach doesn't yield as much energy gain as mixed species in poor soil, nor does it have the same environmental effects," Jason Hill, a post-doctoral researcher who worked with Tilman, said in a statement. Minnesota has 1.5 million acres of farmland set aside for conservation. If the government allowed cultivation on that land, it could provide a major test of the economic viability of growing and harvesting 16 varieties of prairie grass, Tilman said. Spokesmen for the ethanol industry and corn growers offered divided reactions. "Ethanol is ethanol," said Bob Dinneen, president of the Renewable Fuels Association in Washington, D.C. "We don't have a bias as to what the feedstock is. The marketplace is going to determine what feedstock will prove to be the most economical." The technology to make ethanol from grass is advancing rapidly, he added. But he raised doubts about whether grasses will supplant corn as a major ingredient. Ron Obermoller, a corn and soybean grower in Brewster, Minn., said he believes corn will remain king in ethanol production. He owns shares of two Minnesota ethanol plants and is a director of the Minnesota Corn Growers Association. He doubts the government ever will free farmland set aside for conservation in order to grow prairie grasses for harvest. "I'm not sure we've got idle land," he said. Conservation land is home to ducks and pheasants and provides hunting grounds and extra revenue for farmers, Obermoller said. On the other hand, if the economics are favorable, he sees benefits in grass cultivation -- even for farmers who now grow corn. While the price of corn is high enough to justify the cost of shipping it great distances, the market prices of prairie grasses are likely to be much lower, dictating clustering of ethanol production plants near the grass fields, he said. "Instead of having big plants, we will have hundreds of smaller plants," he said. "That gives the farmers the chance to invest locally." ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ SpamWall: Mail to this addy is deleted unread unless it contains the keyword "igve". _______________________________________________ Futurework mailing list [email protected] http://fes.uwaterloo.ca/mailman/listinfo/futurework
