On January 6, the Clean Fuels Development Coalition released a white paper, ‘Re-thinking the Carbon Reduction Value of Corn Ethanol Fuel.’  Author Ron Alverson, former president of the South Dakota Corn Growers Association, writes that despite new science and several updates to the model that regulators use to determine the emissions profile of various fuels, the EPA and the California Air Resources Board continue to use a model that is seven years old.  Scientists at the Argonne National Lab are tasked with modelling the carbon intensity of transportation fuels, including biofuels. Since 2008, they have found decreasing energy use and increased outputs and efficiency at ethanol plants.  While these improvements have been incorporated into the model built by Argonne, the updated model has not been adapted by EPA or state regulators.  The result has been a distortion of the effects of ethanol production on land use and the environment, with ethanol production and use subsequently being labelled as bad as or worse than gasoline from a greenhouse gas perspective. 

The Renewable Fuel Standard (RFS) mandates that corn ethanol must achieve greenhouse gas (GHG) reductions of 20 percent relative to petroleum-derived gasoline, while advanced biofuels and cellulosic biofuels must attain 50 to 60 percent GHG reductions, respectively.  This is measured by carbon intensity, the amount of greenhouse gases (including CO2, nitrous oxide, and methane) that are released per unit of fuel. A “wells to wheels” assessment is calculated by adding the emissions at each production step. For biofuels, this includes emissions and/or carbon sequestration as well as impacts to land from the growing of biofuel crops. A fuel’s carbon intensity is measured primarily by the tool developed by Argonne National Labs, the Greenhouse gases, Regulated Emissions and Energy use in Transportation model, referred to as the GREET model.  

Updates incorporated in more recent versions of GREET include significant reductions in the carbon intensity of ethanol production since 2008; these process improvements include greater energy efficiency, increasing yields per acre, and decreasing water and fertilizer inputs, among other things.  For instance, Alverson writes that energy use for the production of corn-based ethanol dropped 25 percent, corn farming energy use has dropped 24 percent, and ethanol yields have risen three percent since 2008. Soil research also finds that soil organic carbon in corn fields has risen due to increased use of no till and conservation tilling practices.  This is backed up by findings from the U.S. Department of Agriculture’s (USDA) National Resource Conservation Service (NCRS), which also models soil carbon.  According to the most recent GREET model, corn ethanol may already be achieving greenhouse gas reductions much higher than the 20 percent reduction mandated by RFS.

In California, corn ethanol is assessed an Indirect Land Use Penalty (ILUC), based on the assumption that the RFS is a driver of land-use change and deforestation globally.  The result of this penalty is that domestic cellulosic ethanol and imported Brazilian sugarcane ethanol is favored over domestic corn ethanol. Despite concerns over ILUC, there is little evidence that this is occurring, particularly in the United States.  A recent study by Dr. Bruce Babcock, an Iowa State professor and a former California Air Resources Board consultant, supports this finding.  The study examines real-world data on land-use change and concludes, “the primary land use change response of the world's farmers from 2004 to 2012 has been to use available land resources more efficiently rather than to expand the amount of land brought into production. This finding is not necessarily new and it is consistent with the literature that shows the value of waiting before investing in land conversion projects; however, this finding has not been recognized by regulators who calculate indirect land use.” Currently, California is considering lowering the ILUC penalty for ethanol, given new scientific evidence.

On January 7, Oregon’s Environmental Quality Commission approved Phase 2 of the Oregon Clean Fuels Program, which will require a ten percent reduction in GHGs in Oregon transportation fuels over the next ten years.  The standard could incentivize further use of biofuels, biogas, natural gas, propane and electricity into the state’s transportation sector.  It is now up to the state legislature to extend the program, currently set to expire at the end of 2015.  Significantly, Oregon elected to leave ILUC calculations out of their standard. While Oregon and California should be applauded for considering new evidence related to indirect land use change, it is equally important to require EPA and state regulators to use the most up-to date GREET model. 


For more information see:

Re-thinking the Carbon Reduction Value of Corn Ethanol Fuel, Ethanol Across America 

Oregon vote approves second phase of Clean Fuels Program, Ethanol Producer