Jasmin Melvin, PlanetArk 11 May 09;
WASHINGTON - Using switchgrass and other biomass to power electric cars is three times more efficient and more environmentally friendly than using ethanol to power traditional gasoline cars, US scientists have found.
Electric vehicles using biomass converted into electricity travelled 81 percent farther per acre of cropland than vehicles with internal combustion engines running on cellulosic ethanol, researchers in California found.
A small sport utility vehicle could do 9,000 highway miles (14,484 km) on the energy produced from an acre of switchgrass converted into ethanol. But converting that biomass into electricity allowed a battery-powered SUV to get 14,000 miles (22,531 km) on the highway, the study published in Science magazine said.
"One of the driving factors that lead to this result is that the electric motor is much more efficient than the internal combustion engine," said the lead author of the study Elliott Campbell, an assistant professor at the University of California, Merced.
"For the small SUV class of vehicles, the electric motor was 3.1 times the efficiency of the internal combustion engine vehicle," he said.
Bioelectricity can be produced at existing coal-fired power plants by blending up to 15 percent biomass with coal, similar to the process where ethanol is blended with gasoline.
Both ethanol and bioelectricity help reduce carbon dioxide
from being released into the atmosphere.
But both require some greenhouse gas emissions to make and process the plants used as biomass.
"It's not 100 percent efficient so you end up only offsetting some fraction of the amount of emissions you would have created if you drove a traditional gasoline car," said study co-author David Lobell, a senior research scholar at Stanford's Program on Food Security and the Environment.
The electric vehicles offset 108 percent more greenhouse gas emissions than the vehicles using ethanol.
PRICE AN ISSUE
The International Energy Agency predicted global sales for hybrid electric vehicles to triple by 2012 to 2.2 million units. It forecast hybrids to represent less than 10 percent of new car sales in 2015, and reported that electric vehicles would have an even smaller share.
"There's certainly a lot of interest in electric cars, but there's certainly a reluctance to pay more money for these cars," Campbell said.
General Motors said its battery-powered Chevy Volt is slated for release in 2010. Ford Motor Co announced on Thursday that it would retool an SUV and truck factory in Michigan to give consumers an electric Ford Focus by 2011.
The study did not look at the cost of amping up bioelectricity generation or the cost of electric cars.
"Without looking at the economics, we can't really say that this is the final answer by any means but it highlights something that was not really appreciated by people," Lobell told Reuters.
He noted that electricity generation from biomass would be more costly than traditional generation.
"If we are trying to be carbon neutral and produce transportation in a way that doesn't cause climate change, then we have to limit ourselves to renewable energy sources," Lobell said.
(Reporting by Jasmin Melvin; Editing by Lisa Shumaker)
