Studies: Ethanol production doesn't affect land use changes

By Erin Voegele | February 04, 2009
Web exclusive posted March 2, 2009, at 9:08 a.m. CST

A new study on indirect land use has found that the expansion of corn-based ethanol production to meet the renewable fuels standard (RFS) goal of 15 billion gallons per year by 2015 is unlikely to result in the conversion of non-agricultural lands in the U.S. or abroad. The study, titled "Land Use Effects of U.S. Corn-Based Ethanol," was authored by Thomas Darlington of Air Improvement Resource Inc. Darlington presented his findings Feb. 24 at the National Ethanol Conference in San Antonio.

According to Darlington, previous studies of indirect land use have projected that land use changes account for up to 103 grams of carbon dioxide per mega joule of fuel that's produced. In comparison, Darlington's study found that land use impacts of expanding corn-based ethanol in the U.S. between 2001 and 2015 is zero.

During his presentation, Darlington said the conventional theory governing previous studies assumed that corn used for ethanol production in the U.S. leads to a reduction of corn and soybean exports. In response, farmers in the U.S. and in other nations expand production by bringing more land into agricultural production, which releases carbon stored in the soil and above ground plants.

Alternatively, the study conducted by AIR Inc. used the philosophical assumption that if U.S. exports remain constant or increase, no international land use effects should be assigned to corn-based ethanol. The ability to continue to export corn at the same, or increasing, levels can be attributed to increased crop yield, which the study assumes will reach 180 bushels per acre by 2015. In addition, the development of distillers grains coproducts leads to land use credits that are much more significant than previously thought. Previous studies and models that have been developed typically credit distillers grains as a pound per pound replacement for corn. However, Darlington said recent feed studies have found that distillers grains can replace corn and soy in a ration of 1 to 1.28, which leads to a much higher land use credit.

The indirect land use metric being developed by California's Air Resource Board currently assigns corn-based ethanol a 30 gram of carbon dioxide equivalent per mega joule of fuel that's produced, Darlington said. CARB's analysis also estimated land use changes between 2001 and 2015, but didn't make the same philosophical assumptions AIR Inc. made in its study. While CARB metric does take into account some yield improvements, Darlington said adjustments still need to be made.

AIR's analysis concluded:
  • Using a yield improvement path to 183 bushels of corn per acre in 2015, the increase in corn use for U.S. ethanol production can be met without a decline in corn exports or stocks.

  • Increases in productivity and steady U.S. corn exports mean that any land use changes occurring elsewhere around the world cannot theoretically be attributed to U.S. ethanol expansion.

  • According to Argonne National Laboratory, 1 pound of distillers grains replaces nearly 1.3 pounds of base livestock feed, including soybean meal. As such, the net amount of land required for ethanol production is much lower than previously estimated in other studies that assumed distillers grains replaced only corn on a pound-for-pound basis.

  • The expected increase in agricultural productivity combined with the impact of distillers grains on livestock feeding will result in no new pasture or forest land needed to produce 15 billion gallons of ethanol from corn per year by 2015.

On the same day AIR released the results of its study, a University of Illinois study on land use was also released. That study was commissioned by the Illinois Corn Growers Association and completed by Steffen Mueller from the Energy Resources Center at the University of Illinois at Chicago.

Muller's study focused on a single modern ethanol plant in Rochelle, Ill., and evaluated the plant's effect on local farmlands. The study looked at relevant farming data sourced from within a 40-mile radius of the plant, including satellite imagery and farmer surveys, one year prior to the plant opening and two years after.

Muller's study found that ethanol plant grain demand was quickly met by incremental production improvements. Although farmers had land available to convert to corn production, they did not convert it.

A full copy of the AIR study is available on the Renewable Fuels Association website.