Group: No liquid coal

WASHINGTON, Nov. 13 (UPI) -- The Washington-based Union of Concerned Scientists warns some alternative fuels may be more polluting than others.

Heightened concern about oil dependence is driving support for alternative transportation fuels, but some, like liquefied coal, may give off more emissions than gasoline or diesel, according to a new report issued Tuesday by the Union of Concerned Scientists.

Transportation is responsible for two-thirds of the nation's oil consumption and nearly 40 percent of U.S. emissions. In order to cut emissions from this sector, there must be improved vehicle fuel efficiency and smart growth policies as well as clean fuel alternatives.

"We need to wean ourselves off oil, but we should replace it with the cleanest alternatives possible," said Patrician Monahan, author of the report and deputy director of UCS's Clean Vehicles Program. "Let's not trade one bad habit for another."

Corn ethanol was found to be either more polluting or less than gasoline, depending on how the corn is grown and the ethanol is produced, but liquid coal can release 80 percent more emissions than gasoline. On average, corn ethanol can reduce emissions about 20 percent. The cleanest alternative found in the report is cellulosic ethanol from grasses or wood chips, which can reduce emissions by more than 85 percent.

"Biofuels have a Jekyll and Hyde reputation depending on what study you read and what assumptions you make," Monahan said. "But liquid coal is a loser no matter how you look at it. We need to set standards so farmers know the right way to produce cleaner fuels."