Corn-based Ethanol Fares Poorly in Biofuel Study
Research led by a biologist at the University of Washington, Bothell, shows that some of the most popular current biofuel stocks -- ethanol, vegetable oil, and others -- might have unintended impacts.
The authors of a paper published in the June issue of the journal Conservation Biology offer a dozen policy recommendations to promote sustainability and biodiversity in biofuel production.
The study looked at factors such as the energy needed to produce a renewable fuel source compared with how much energy is produced, the impact on soil fertility and effects on food supply when fuels based on crops such as corn and soybeans are mixed with fossil fuels. Based on those factors, the authors determined that corn-based ethanol is the worst alternative overall.
"It's foolish to say we should be developing a particular biofuel when that could mean that we're just replacing one problem with another," said lead author Martha Groom of the UW Bothell. Co-authors are Elizabeth Gray of The Nature Conservancy and Patricia Townsend of the UW Seattle.
The authors argue that precise calculations are needed to determine the ecological footprints of large-scale cultivation of various crops used for biofuels.
They note, for example, that because such large amounts of energy are required to grow corn and convert it to ethanol, the net energy gain of the resulting fuel is modest. Using a crop such as switchgrass, common forage for cattle, would require much less energy to produce the fuel, and using algae would require even less. Changing direction to biofuels based on switchgrass or algae would require significant policy changes, since the technologies to produce such fuels are not fully developed.
The paper's policy suggestions are "not definitive at all," Groom said, "but rather each category calls out a question and is a starting point in trying to find the proper answers."
A difficulty, Groom said, is that while escalating prices add pressure to find less costly fuel sources, acting too hastily could create a host of other problems. For example, farmers who plant only corn because it is suddenly profitable, and don't rotate with crops such as soybeans, are likely to greatly deplete their soil, which could limit crop growth, and promote soil erosion.
The study is a synthesis of peer-reviewed research published in a various journals. The scientists examined the literature looking for indicators of biofuels that are more sustainable and carry a smaller ecological footprint, then used that information to derive the policy recommendations.