Posted August 19, 2015
There’s more scholarly research challenging the oft-heard claim that the Renewable Fuel Standard (RFS) and its requirements for increasing use of biofuels is good for the environment and climate.
Now a paper published this month by University of Michigan Energy Institute researchers argues that the government-sponsored model used to calculate biofuels’ carbon footprint is flawed. The paper says a more accurate accounting method shows that corn ethanol doesn’t have an edge over petroleum gasoline when it comes to reducing CO2 emissions.
Research by the institute’s John DeCicco and Rashmi Krishnan (sponsored by API) found that assumed biofuel carbon neutrality that’s built into the government-sponsored model “does not hold up for real-world biofuel production.” The paper:
Direct accounting of actual carbon flows shows that, at best, corn ethanol production fails to reduce CO2 emissions relative to petroleum gasoline, and even that result depends on the gain in cropland carbon uptake that occurs with a large shift from growing soybeans to growing corn. If the baseline land use was corn production, then the increase in GHG emissions due to ethanol production would be significantly higher. Finally, if consequential effects including [indirect land-use change] were to be included, the result would be a yet even higher estimate of the adverse net GHG emissions impact of biofuel use.
The paper says that results from government-sponsored lifecycle analysis (LCA), which forms the basis for the RFS’ claimed environmental benefits, are “highly variable.” It says the LCA model doesn’t correctly represent the “terrestrial carbon cycle,” making its use “problematic” for biofuels. It continues:
This analysis highlights the critical importance of baseline carbon uptake on the land from which a biofuel feedstock is sourced. In the LCA methods used for fuels policy, baseline carbon uptake is automatically and fully credited against tailpipe CO2 emissions, a modeling convention equivalent to assuming that uptake was zero before the feedstock was harvested for producing biofuel rather than for feed and food. But baseline carbon uptake is never zero on productive land and is in fact substantial for existing cropland, the main source of biofuels produced at commercial scale.
DeCicco called for repealing the RFS in a blog published in The Hill earlier this month:
What about the claims that renewable fuels help the environment and slow global warming? Unfortunately, in the real-world of commercial biofuel production as opposed to an imaginary world of fantasy fuels advocated by special interests, those claims are untrue. After a decade of expansion, the facts on the ground reveal that biofuels – far from being cleaner-burning alternatives as promised – are worsening greenhouse gas emissions and harming the environment in many other ways. .
The carbon case for biofuels, DeCicco writes, stems from plants absorbing CO2 while they’re growing, with that absorbed carbon offsetting CO2 that’s emitted when corn ethanol is burned. This “carbon neutrality” for biofuels, he writes, is assumed in reports that claim there are CO2 reduction benefits in biofuels use – basically, an assertion that biofuels are “green.” DeCicco:
… the notion that biofuels are carbon neutral when they replace petroleum fuels is based on an incomplete and incorrect understanding of the science of plant growth and the carbon cycle. Careful analysis … has exposed serious flaws in the government-sponsored modeling used to justify the RFS. Once one corrects the carbon accounting, it negates any possibility that corn ethanol might have a climate benefit and entirely erodes the environmental argument for the mandate. Nearly all of the farm fields used to produce corn ethanol and other biofuels were already growing crops for other purposes. Carbon was already being absorbed from the air by the cropland, and so it is wrong to credit that carbon against the CO2 emitted when the biofuels are burned.
The Michigan research is a significant addition to the RFS debate, because claimed environmental benefits have been at the core of arguments for keeping the RFS – along with arguing that increased ethanol use helps crude oil imports. Like claimed environmental benefits, the imports argument evaporates under analysis (see here and here) that shows surging domestic crude oil production, not ethanol output, is mostly responsible for falling imports.
Subtract arguments for the RFS that are based on the environment and reducing imports, and there’s not a whole lot left to justify keeping the RFS in place – with its potential risks for consumers and the broader economy. As Ken Cohen writes on the Perspectives blog, the RFS is a solution searching for a problem. Repeal the RFS.
ABOUT THE AUTHOR
Mark Green joined API after a career in newspaper journalism, including 16 years as national editorial writer for The Oklahoman in the paper’s Washington bureau. Mark also was a reporter, copy editor and sports editor. He earned his journalism degree from the University of Oklahoma and master’s in journalism and public affairs from American University. He and his wife Pamela live in Occoquan, Va., where they enjoy their four grandchildren.