Alternative Fuel 'Carbs' Count, Report Says

Using alternative fuels to power our cars and trucks might decrease our dependence on foreign oil, but some alternatives are better than others when it comes to greenhouse gas emissions, according to a new report from the Union of Concerned Scientists (UCS).

Depending on how they are created, for example, biofuels -- fuel made from corn, grass or wood chips -- could help reduce greenhouse gas emissions by anywhere from 20 to 80 percent, the UCS report stated. Making liquid fuel from coal, on the other hand, would aggravate rather than reduce climate change.

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

In her report, Monahan recommends taking a "till to tailpipe" approach to decide which alternative fuels are best. That means taking into account all the pollution created by each alternative fuel -- not just from car and auto emissions, but farming practices, fertilizer use, processing demands and more. The lower the total start-to-finish carbon emissions, the better the alternative fuel is for the environment.

"Government policies and high oil prices have whetted our growing appetite for all alternative fuels, good and bad alike," said Eli Hopson, the UCS's Washington representative for Clean Vehicles. "With the wrong policy, liquid coal could displace cleaner alternatives. Biofuels can be a staple of our low carbon fuel diet, but only if policies are in place that 'count carbs' and 'make carbs count.' "

Currently, about two-thirds of the U.S.'s oil consumption is for transportation. Fossil fuels used in cars, trucks and other vehicles also account for nearly 40 percent of the nation's greenhouse gas emissions.