Study Reveals Corn Ethanol Use Reduces Carbon Footprint, Diminishes Greenhouse Gases

At the U.S. Department of Energy’s (DOE) Argonne National Laboratory, a study performed by scientists discloses that the use of corn ethanol is decreasing the carbon footprint and reducing greenhouse gases.

Study Reveals Corn Ethanol Use Reduces Carbon Footprint, Diminishes Greenhouse Gases
The use of corn ethanol from 2005 to 2019 has reduced the carbon footprint in the United States and diminished greenhouse gases, according to an Argonne study. Image Credit: Smileus/Shutterstock.

The study, which was reported recently in the journal Biofuels, Bioproducts and Biorefining, examines the production of corn ethanol in the United States from 2005 to 2019 when production was more than quadrupled.

Researchers evaluated the greenhouse gas (GHG) emission intensity (occasionally called carbon intensity, or CI) of corn ethanol during that period and discovered a 23% decrease in CI.

As per the Argonne researchers, production of corn ethanol increased over the period, ranging from 1.6 to 15 billion gallons (6.1 to 57 billion liters). Supportive biofuel policies like the Environmental Protection Agency’s Renewable Fuel Standard and California’s Low-Carbon Fuel Standard powered this increase.

Both of those federal and state programs assess the life-cycle GHG emissions of fuel production pathways to estimate the advantages of using renewable fuels.

To evaluate emissions, researchers make use of a process known as life-cycle analysis, or LCA—the standard technique utilized for comparing relative GHG emission effects among various fuel production pathways.

Since the late 1990s, LCA studies have demonstrated the GHG emission reduction benefits of corn ethanol as a gasoline alternative. This new study shows the continuous downtrend of corn ethanol GHG emissions.

Michael Wang, Study Principal Investigators and Senior Scientist, Argonne National Laboratory

Wang heads the Systems Assessment Center in the laboratory’s Energy Systems division.

The corn ethanol production pathway—both in terms of corn farming and biorefineries—has evolved greatly since 2005.

Uisung Lee, Study First Author and Analyst, Argonne National Laboratory

Lee noted that the study depended on extensive statistics of corn farming from the U.S. Department of Agriculture and of corn ethanol production from industry benchmark data.

A study coauthor named Hoyoung Kwon reported that U.S. corn grain yields increased by 15%, achieving 168 bushels for each acre in spite of fertilizer inputs continuing to be constant and leading to a reduced intensity in fertilizer input per bushel of corn that was harvested: reductions of 18% in potash use and 7% in nitrogen use.

May Wu, another co-author, added that yields of ethanol increased by 6.5%, with a decrease of 24% in ethanol plant energy use.

With the increased total volume and the reduced CI values of corn ethanol between 2005 and 2019, corn ethanol has resulted in a total GHG reduction of more than 500 million tons between 2005 and 2019. For the United States, biofuels like corn ethanol can play a critical role in reducing our carbon footprint.

Michael Wang, Study Principal Investigators and Senior Scientist, Argonne National Laboratory

For this study, Argonne’s GREET® model was utilized by the Argonne team. Argonne designed a model called GREET (the Greenhouse gases, Regulated Emissions, and Energy use in Technologies), a unique LCA analytical tool that simulates the energy use and emissions output of several vehicles and fuel combinations. Around the world, government, industry, and other scientists make use of GREET® for LCA modeling of corn ethanol and other biofuels.

The study was financially supported by DOE’s Vehicle Technologies in the Office of Energy Efficiency and Renewable Energy.

Journal Reference:

Lee, U., et al. (2021) Retrospective analysis of the U.S. corn ethanol industry for 2005–2019: implications for greenhouse gas emission reductions. Biofuels, Bioproducts & Biorefining.


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