NEW YORK – A gasoline alternative may be found in prairie grass. A team of economists and ecologists at the University of Minnesota say that “these diverse grassland species constitute a carbon-negative source of energy that could alleviate 19 percent of global electricity consumption and 13 percent of the world's petroleum consumption,” the Scientific American reports.

Ecologist David Tilman said that in five to seven years, the source of biofuels could expand to include cellulose, a plant sugar known to be an ethanol-rich source. "When we turn that corner," Tilman told the magazine, "we want to have available the most efficient way of producing cellulose to be a biomass feedstock."

Based on his extensive work with crops, Tilman has surmised that nitrogen-poor, degraded land planted with a mixture of perennial prairie grasses – such as goldenrod, Indian grass, big blue stem and switchgrass – could provide up to 238 percent more bioenergy than the same land planted with only one species. He also claims his plots can return 51 percent more energy per acre when compared with ethanol from corn grown in fertile soil.

His process is reportedly carbon-negative, which means that the plants can store more carbon in their roots than they will create during their conversion to biofuels or electricity. Tilman attributes this negativity to prairie grasses’ complex root systems underground that typically make up two thirds of the plant total biomass, making them efficient carbon sinks. "When they grow, they have to [absorb] a lot of carbon to keep their roots alive and to make these very extensive root systems," Tilman told the magazine. These diverse systems may use more nitrate, "the limiting nutrient" in the soil, which starves bacteria that decomposes carbon, allowing the plants to better maintain their roots.

However, the production of ethanol from grasses is currently hypothetical because of economic constraints.