EPA's Biofuel Mandates Based on Shaky Assumptions, Scientists Say

Federal renewable fuel mandates have created an industry around corn ethanol that now consumes nearly a third of the U.S. corn crop. But what is the rationale behind those mandates in the first place? Several scientists have asked and found the answers to be unsound.

When the Environmental Protection Agency revised its renewable fuel standards in February, the agency recalculated the lifecycle emissions of corn ethanol to find that it was 20 percent less greenhouse-gas emitting than gasoline and, therefore, qualified as a renewable fuel. Some wondered what had changed since an EPA review issued less than a year before found that emissions from corn ethanol were too high for it to qualify.

As it turns out, none of the actual data about emissions from biofuels changed — just the way the EPA presented it.

Specifically, the agency's new fuel standards assess each biofuel based on its assumed greenhouse gas emissions in the year 2022, the deadline by which renewable fuel production must be at levels mandated by the Energy Security and Independence Act of 2007.

But focusing on the amount biofuels are expected to emit in 2022 “distorts the picture of today's biofuels,” according to Jeremy Martin, a senior analyst in the Union of Concerned Scientists' Clean Vehicles Program. Lifecycle emissions from corn ethanol, for instance, are only expected to decline in 2022 because of expected increases in the yields of corn crops and improvements in biorefining technology by that year.

Even the EPA's own analysis “shows that, in the near term, natural-gas-powered, dry-milled corn ethanol production results in an increase of greenhouse gas emissions of 12 to 33 percent compared to gasoline,” says Joe Fargione, a lead scientist at the Nature Conservancy. Those numbers can be found in spreadsheets that the agency posted to its own Web site.

In March, the American Petroleum Institute and the National Petrochemical & Refiners Association sued the EPA over the new standards. The two groups argue that by publishing the standards after an original deadline, the EPA has left oil companies with obligations to buy and supply biofuels that will raise gasoline prices unfairly if oil companies are forced to meet those obligations on time.

A lawsuit against the EPA also seems warranted, though for different reasons, to Richard Plevin, a Ph.D. candidate in the Energy and Resources Group at the University of California, Berkeley, who studies the lifecycle emissions of biofuels.

“I think it's completely reasonable for environmental groups to sue the EPA based on its own analysis and say, 'These fuels don't meet the requirements of the program,'” Plevin argues.

Plevin recently spoke about the issue before a National Research Council committee which is reviewing projections of future U.S. biofuel production and its impacts, including the EPA's own new renewable fuel standards.

According to the agency's final review of the standards, 2022 emissions were the focus because, in part, it would be too difficult to “track how biofuel production might continuously change from month to month or year to year.” But the EPA already has published estimates of emissions from most biofuels in 2012 and 2017 — the increase that Fargione described, for instance, is projected to occur in 2012. So why were the 2022 numbers the only ones used in the final review?