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Driving down greenhouse gas emissions

Driving down greenhouse gas emissions
U.S. Department of Agriculture lead researcher Jan Lewandrowski

Continuing gains in farmers’ productivity, along with efficiency improvements by ethanol plants, are driving down greenhouse gas (GHG) emissions in the production of corn-based ethanol, according to a new study by the U.S. Department of Agriculture (USDA). Those gains, according to lead researcher Jan Lewandrowski, will help make corn-based ethanol more competitive in markets, both domestic and foreign, which are demanding fuels produced with reduced GHG emissions.

“What we’ve done is shown that corn ethanol does have a place at the GHG mitigating table and can be an option for states, or for countries, that want to reduce emissions,” Lewandrowski said recently during an interview for the Iowa Farm Bureau’s Spokesman Speaks podcast.

The USDA study, released this spring, found that GHG emissions from corn-based ethanol production are about 39% lower than gasoline. Reductions in GHG emissions are even better, down 43%, if the biofuel plant is fueled by natural gas, as most in Iowa are today.

The USDA study revisited an earlier study by the Environmental Protection Agency (EPA), which had determined that corn-based ethanol produced only a 21% reduction in GHG emissions when compared to gasoline. The EPA study, done in 2010, was based on an assumption that the increased demand for corn to make ethanol would spur farmers to convert large amounts of land from pastures and grasslands, which was expected to raise GHG emissions.

With more real-world data available, the USDA economists decided to take another look at ethanol’s GHG emissions. They found that demand for ethanol did prompt farmers to harvest more corn, but there was far less new land brought into production than earlier projected, meaning that GHG emissions did not rise as expected.

More from existing acres

Instead, Lewandrowski said, the data showed farmers’ gains in productivity allowed them to fill the additional demand from ethanol by harvesting more corn from existing acres. Farmers accomplished the productivity gains by installing more drainage in wet areas, irrigation in dry areas, as well as adopting new genetics and technology, he said.

“The land use response was very different than researchers thought it would be in 2010,” Lewandrowski said. “We’ve been increasing average corn yields about two bushels per acre per year for a lot of years. Those gains start to add up.”

Another factor in lowering emissions from ethanol production was farmers’ push to adopt conservation practices, such as reduced tillage and cover crops, the USDA study showed. Those practices can  trim the emissions of GHG at the farm level even further, Lewandrowski said.

Along with farmers, corn-based ethanol plants are continually pushing to be more efficient. Over the years, plants have made significant gains in extracting more biofuel from each bushel of corn and at increasing energy efficiency.

“They are getting more ethanol with less energy. If that energy is generated by fossil fuel, it means less GHG emissions,” Lewandrowski said.

The work by the USDA economists was hailed by U.S. Agriculture Secretary Sonny Perdue.

“These new findings provide further evidence that biofuels from America’s heartland reduce greenhouse gases even more than we thought, and that our farmers and ethanol plants continue to become more efficient and effective,” he said in a news release.

Biofuel advocates also welcomed the USDA research. “This new USDA study further supports that ethanol is a win-win for all Americans,” said Emily Skor, CEO of Growth Energy.



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