USDA report demonstrates GHG benefits of corn ethanol

By Erin Voegele | January 12, 2017

On Jan. 12, the USDA released a report showing the greenhouse gas (GHG) emissions associated with U.S. corn ethanol are currently approximately 43 percent lower than gasoline when measured on an energy equivalent basis. Over the next several years, the GHG profile of ethanol is expected to improve even more.

Unlike other studies of GHG benefits that rely on forecasts of future ethanol production systems and expected impacts on the farm sector, the USDA said this report, titled “A Life-Cycle Analysis of the Greenhouse Gas Emissions of Corn-Based Ethanol,” reviewed how the industry and farm sectors performed over the past decade to assess the current GHG profile of corn-based ethanol.

"This report provides evidence that corn ethanol can be a GHG-friendly alternative to fossil fuels, while boosting farm economies," said Agriculture Secretary Tom Vilsack.

According to the USDA, the report found greater lifecycle GHG benefits from corn ethanol than a number of earlier studies, driven by a variety of improvements in ethanol production, from the corn field to the ethanol refinery. The USDA noted farmers are producing corn more efficiently and using conservation practices that reduce GHG emissions, including reduced tillage, cover crops and improved nitrogen management. In addition, corn yields are improving, increasing by more than 10 percent between 2005 and 2015.

Over the same 10-year time period, U.S. ethanol production grew from 3.9 billion gallons per year to 14.8 billion gallons per year. As production volumes increased, advances in production technologies, including the use of combined-heat-and-power (CHP), landfill gas-to-energy, and the coproduction of biodiesel, helped reduce GHG emissions at ethanol plants.

Given current trends, the report said by 2022 the GHG profile of corn ethanol is expected to almost 50 percent lower than gasoline, primarily due to improvements in corn yields, process fuel switching and transportation efficiency.

The report also examines a variety of factors that could enhance the GHG benefits of corn ethanol, and provides estimates of how those factors could change ethanol’s lifecycle GHG emissions. For example, in a scenario where efficiency improvements are made at ethanol plants and corn-producing farms adopt additional conservation practices, the GHG benefits of corn ethanol increase to approximately 76 percent reduction when compared to gasoline.

The USDA said there are several reasons this report found greater lifecycle GHG benefits from corn ethanol than several earlier studies, including indirect land use change (ILUC). Based on new data and research, the USDA said there is compelling evidence that while land use changes have occurred, the actual pattern of changes and innovation within the farm sector have resulted in these indirect emissions being much lower than previously projected.

“Recent studies of international agricultural land use trends show that that 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 used for farming,” said the USDA in a statement. “Instead of converting new land to production, farmers in Brazil, India and China have increased double cropping, expanded irrigation, reduced unharvested planted area, reduced fallow land and reduced temporary pasture. Much of the international attention on supply of corn for ethanol has focused on Brazil, where earlier estimates anticipated conversion of rainforests to commodity production. But between 2004 and 2012, at the same time U.S. corn ethanol production increased more than 200 percent, deforestation in Brazil's Amazon decreased from 10,200 to 2,400 square miles per year.”

The Renewable Fuels Association has responded to the USDA’s study. “We are pleased that USDA’s analysis reflects the tremendous efficiency gains our industry has made and continues to make. This is not your grandfather’s ethanol industry,” said Bob Dinneen, president and CEO of the RFA. “Today’s farmers and ethanol producers use less energy than ever before, have lowered costs with new value-added markets and technologies, and evolved into the most cost-effective, cleanest-burning source of octane on the planet. Moreover, as this study proves, concerns about land use change were terribly overblown, and U.S.-produced corn ethanol is a stone-cold winner for the environment, providing dramatic reductions in greenhouse gas emissions.”

“The U.S. ethanol industry has proven that economic growth and environmental stewardship are not mutually exclusive,” he continued. “We can provide consumers with another American fuel choice at the pump that both lowers gasoline prices locally and addresses climate change globally.”

“USDA and Secretary Vilsack have done a tremendous service by releasing this study after such a comprehensive and thorough analysis, using real world data and peer-reviewed assumptions,” Dinneen said. “This should answer the critics who have repeated Big Oil’s polemic that renewable biofuels somehow increase carbon emissions. Clearly, the opposite is true. As many counties across the globe contemplate measures to address climate change, U.S. ethanol producers have a solution.”

Growth Energy also applauded the results of the study. “This USDA report clearly demonstrates what we have known for years—that biofuels like ethanol are the most effective alternative to fossil fuel and a critical tool for reducing greenhouse gas emissions and improving air quality,” said Emily Skor, CEO of Growth Energy. “Ethanol is an earth-friendly biofuel produced in America that not only significantly reduces greenhouse gas emissions, but also improves engine performance and saves consumers money at the pump.”

“As the report notes, corn ethanol has the potential to reduce greenhouse gas emissions by up to 76 percent when accounting for advancements in production efficiency techniques and sustainable agricultural practices,” Skor said. “The ethanol industry works every day to improve production processes, ensuring that ethanol will continue to provide even greater benefits well into the future. The ethanol industry is proud to provide a product that helps clean our air, improves engine performance, and saves consumers money when they fill up their tank.”

A full copy of the report can be downloaded from the USDA’s website.