Thursday, May 21, 2009

Bioelectricity Creates Questions about Ethanol’s Efficiency

"For these beneficial approaches, we could do more to fight climate change by making electricity than making ethanol," said field and lead author Elliot Campbell of the University of California, Merced.

In a recent study published in Science Magazine, ethanol and bioelectricity were compared to determine their environmental impacts. Two factors were considered: how much cropland is used and the effectiveness at reducing greenhouse gas emissions when used as fuel.

Ethanol is a liquid fuel that can be used like gasoline to power vehicles. It is produced from plant biomass, like corn or switchgrass. Bioelectricity comes from the same type of source—biomass—but in this case the biomass is used to produce electricity, which is then used to power an electric car battery.

Bioelectricity outpaced ethanol by 81% in terms of land use, and it also offset 108% more greenhouse gas emissions. The source of the biomass did not affect the results; bioelectricity was the clear winner. For example, a small SUV could travel about 14,000 miles using bioelectricity produced from an acre of switchgrass, but it could only travel 9,000 miles using ethanol made with the same parameters. Bioelectricity is even more appealing because it has more potential to make use of carbon capture technology, which would offset even more carbon emissions.

Campbell offered an explanation for ethanol’s poor performance relative to bioelectricity.

"The internal combustion engine just isn't very efficient, especially when compared to electric vehicles," said Campbell. "Even the best ethanol-producing technologies with hybrid vehicles aren't enough to overcome this."

Still, more research should be completed before concluding that bioelectricity is the best approach.

"We also need to compare these options for other issues like water consumption, air pollution, and economic costs," said David Lobell of Stanford’s Program on Food Security and the Environment.

For more information on this study, go here.

No comments: