Corn-based ethanol may be more emission-intensive than previously thought and is likely contributing to more emissions than gasoline, a new study finds.

The study, published in Proceedings of the National Academy of Sciences, suggests that the environmental benefits of the U.S. renewable fuel standard (RFS) remain unclear.

Under the Renewable Fuel Standard, oil refiners are required to blend growing amounts of renewable fuels into gasoline and diesel.

The RFS raised corn prices, which in turn expanded the land used for corn crops. This increases emissions from the conversion of land to corn crops, and raises fertilizer and water usage, says the study, funded in part by the National Wildlife Federation.

“These changes increased annual nationwide fertilizer use by 3 to 8%, increased water quality degradants by 3 to 5%, and caused enough domestic land use change emissions such that the carbon intensity of corn ethanol produced under the RFS is no less than gasoline and likely at least 24% higher,” the authors of the study write.

The study contradicts previous findings, including a study published in 2019 saying that the greenhouse gas (GHG) emissions from corn ethanol are about 39 percent lower than gasoline on an energy equivalent basis.

Carbon capture and storage alongside biofuel production could play a role in holding global warming below 2 degrees Celsius, the latest study says.

“However, our findings confirm that contemporary corn ethanol production is unlikely to contribute to climate change mitigation,” the authors point out.

“Corn ethanol is not a climate-friendly fuel,” Tyler Lark, Assistant Scientist at University of Wisconsin-Madison Center for Sustainability and the Global Environment (SAGE) and lead author of the study, told Reuters.

According to the ethanol trade group, the Renewable Fuels Association, “the authors of this new paper precariously string together a series of worst-case assumptions, cherry-picked data, and disparate results from previously debunked studies to create a completely fictional and erroneous account of the environmental impacts of the Renewable Fuel Standard,” Geoff Cooper, RFA President and CEO, said in a statement.

By Charles Kennedy for Oilprice.com

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