Bioelectricity more efficient than ethanol to power vehicles

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A study by the University of California, Merced suggests that bioelectricity – biomass converted to electricity – could be more efficient than ethanol as an alternative clean fuel for vehicles.

Scientists are examining biomass – plant matter used to generate energy – as a potential power source. The two ways that energy can be generated from biomass are to convert it to ethanol or to electricity. Ethanol can power a vehicle by serving as fuel for an internal combustion engine. Biomass can be converted to electricity to fuel a vehicle powered by an electrical battery.

According to the study headed by UCMerced Assistant Professor Elliot Campbell, biomass used to generate electricity could be the more efficient way to use biomass as a renewable clean energy source for transportation use.

In the study, Campbell, along with Christopher Field, director of the department of global energy at the Carnegie Institution and David Lobell of Stanford University, the scientists found that biomass converted into electricity produced 81% more transportation miles and 108% more emissions offsets compared to ethanol.

The scientists based their study on two criteria: miles per area cropland and greenhouse gas offsets per area cropland. In both cases, scientists considered a range of feedstock crops, focusing primarily on corn and switchgrass and four vehicle types: small car, mid-size car, small SUV, and large SUV.

First, they looked at how many miles a range of vehicles powered by ethanol could travel versus a range of electric vehicles fueled by electricity. Second, they examined offsets to greenhouse gas emissions for ethanol and bioelectricity.

The researchers are careful to point out that their study looked at two criteria, which are transportation and greenhouse gas offsets, but did not examine the performance of electricity and ethanol for other policy-relevant criteria.

"We also need to compare these options for other issues such as water consumption, air pollution and economic costs," Campbell said.


-  Katrice R. Jalbuena

Sources:

¹ http://www.ucmerced.edu/news_articles/05072009_study_suggests_bioelectricity_could.asp
² http://www.ucmerced.edu/