In 2007, the U.S. Congress mandated the blending of biofuels such as corn-based ethanol into gasoline. One of the top goals: reducing greenhouse gas emissions. But today, the nation’s ethanol plants produce more than double the climate-damaging pollution, per gallon of fuel production capacity, than the nation’s oil refineries, according to a Reuters analysis of federal data. The average ethanol plant chuffed out 1,187 metric tons of carbon emissions per million gallons of fuel capacity in 2020, the latest year data is available. The average oil refinery, by contrast, produced 533 metric tons of carbon.
The ethanol plants’ high emissions result in part from a history of industry-friendly federal regulation that has allowed almost all processors to sidestep the key environmental requirement of the 2007 law, the Renewable Fuel Standard (RFS), according to academics who have studied ethanol pollution and regulatory documents examined by Reuters. The rule requires individual ethanol processors to demonstrate that their fuels result in lower carbon emissions than gasoline. The Environmental Protection Agency (EPA) is charged with writing the regulations to meet the goals set by Congress. For processors, that translates to an EPA requirement that the plants use certain emissions-control processes the agency assumes will result in lower-than-gasoline emissions. But the agency has exempted more than 95% of U.S. ethanol plants from the requirement through a grandfathering provision that excused plants built or under construction before the legislation passed. Today, these plants produce more than 80% of the nation’s ethanol, according to the EPA.
Some of the exempted plants produced much less pollution, including some owned by the same companies producing the highest emissions. The EPA said about a third meet the law’s environmental standard even though they are not required to do so. But as a group, the plants freed from regulation produced 40% more pollution per gallon of fuel capacity, on average, than the plants required to comply, the Reuters analysis found.