November 14, 2007

UCS Report on Biofuels Calls for National Low-Carbon Fuel Standard

Sample lifecycle greenhouse gas emissions relative to a gasoline baseline. Click to enlarge. Source: UCS

Heightened concern about oil dependence is generating growing support for alternative transportation fuels, but some would emit significantly more greenhouse gases on a full lifecycle basis than gasoline or diesel, according to a new report by the Union of Concerned Scientists (UCS).

Transportation is responsible for two-thirds of the nation’s oil consumption and nearly 40% of US greenhouse gas emissions on a life cycle basis. To dramatically cut emissions from this sector, a comprehensive solution must include improved vehicle fuel efficiency, smart growth policies that reduce vehicle miles traveled, and clean fuel alternatives, according to the report.

We need to wean ourselves off oil, but we should replace it with the cleanest alternatives possible. Let’s not trade one bad habit for another.

—Patrician Monahan, author of the report and deputy director of UCS’s Clean Vehicles Program

On a lifecycle basis, for example, liquid coal, can release about 80% more greenhouse gas emissions than gasoline, the report found. Corn ethanol, conversely, could be either more polluting or less than gasoline, depending on how the corn is grown and the ethanol is produced. On average, corn ethanol can reduce emissions about 20%, though there is uncertainty due to differing land use practices. The cleanest alternative, cellulosic ethanol from grasses or wood chips, could reduce emissions by more than 85%.

The report evaluated two scenarios for alternative fuels, one carbon-intensive—meaning that it would produce significantly more greenhouse gases than burning gasoline—and the other low-carbon—meaning that it would produce significantly less. The analysis assumed that alternative fuels will replace 37 billion gallons of gasoline, about 20% of the fuel UCS projects Americans will consume in 2030.

In both scenarios, conventional biofuels would meet 25% of the demand for alternative fuels. In the carbon-intensive scenario, the remaining demand would be met by liquid coal. The carbon-intensive scenario would increase emissions by 233 million metric tons—equivalent to adding about 34 million cars to the road, the number of new cars and light trucks currently sold nationally over a two-year period.

By contrast, the low-carbon scenario relies on advanced biofuels to meet 75% of the demand. That would cut greenhouse gas emissions by 244 million metric tons, akin to taking 35 million of today’s cars off the road.

The report calls for a national low-carbon fuel standard that accounts for alternative fuels’ global warming emissions over their entire life cycle and requires them to emit less pollution than today’s petroleum-based fuels.

Life cycle analysis for alternative fuels could help farmers and the biofuels industry, according to Gregg Heide of the Iowa Farmers Union.

Congress is now considering an energy bill that includes a renewable fuel standard giving the Environmental Protection Agency the authority to develop life cycle analysis guidelines. To date, the federal government has been promoting both cleaner and dirtier fuels. For instance, Congress has approved funding for research into next-generation ultra-clean biofuels, but it also is subsidizing research into liquid coal processing technology.

In January 2007, California Gov. Arnold Schwarzenegger issued an executive order calling for establishing a state low-carbon fuel standard. (Earlier post.) The California Air Resources Board is currently developing regulations that would require manufacturers of transportation fuel sold in the state to reduce per gallon emissions of global warming pollution by at least 10 percent. Arizona, Minnesota, New Mexico, Oregon and Washington State are considering similar policies.

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