At the American Coalition for Ethanol's national conference last week in Milwaukee, experts in the field of studying international land use change debated the different methods behind the calculations. Wally Tyner, professor and energy economist in the Department of Agricultural Economics at Purdue University, and Tom Darlington, President of Air Improvement Resource (AIR) Inc. addressed the conference's general session on "Theory vs. Science: The Role of Biofuels in Low Carbon Policies and Calculating Direct and Indirect Emissions."
Tyner noted that prior to 2007, the general consensus was that corn ethanol had a 20% reduction in greenhouse gas (GHG) emissions, but then in the Energy Independence & Security Act of 2007 came the requirement that indirect land use change be considered in estimating total GHG impacts. He stated that there are a number of issues involved in developing a lifecycle model to quantify these international changes, including how to define the boundaries, deciding what to include and not include, and working with uncertain numbers. "How uncertain are these numbers? And they are uncertain, believe me," Tyner said.
He also mentioned the E10 blend wall, calling it "the biggest issue" facing the ethanol industry. "It's a total block to cellulosic ethanol," Tyner said. "Cellulosic ethanol will never appear without getting over the blend wall."
Tyner believes that, based on Purdue's "GTAP" model, the range today for corn ethanol is minus 9 to minus 23 in terms of lower lifecycle emissions than gasoline.
Tom Darlington has studied the international land use change (ILUC) issue and sees what California has done with its low carbon fuels standard as potentially problematic. Other states are looking to take up the banner on a low carbon fuels standard after California, he noted, saying "I still believe how we do a low carbon fuels standard or RFS2 is a pretty big issue."
"At this point I believe the numbers are not as high as the GTAP model and some of the other models are saying, and I'm not in one camp or the other," Darlington said. He studied the ILUC issue about a year ago for the Renewable Fuels Association and determined that land use change could indeed be zero.
Darlington believes a higher credit should be given for the ethanol co-product distillers grain, which goes back into the livestock feed market. He said that other models traditionally believe distillers grain replaces corn on a pound for pound basis, but a new study shows that especially in dairy cattle, swine, and poultry, distillers may replace some soy, too. One pound of distillers grain replaces nearly 1.3 pounds of corn. Properly accounting for that soy offset should have a land use change credit, Darlington said.
When the models are tweaked according to Darlington's recommendations, the outcome is much more favorable for corn ethanol than under the California model, for example.
"Land use modeling is in its infancy," Darlington said. "Regulations requiring these to be estimated are still far ahead of the models. We believe there is great risk in making bad decisions, and they may be irreversible."
During the Q&A with the audience, Tyner said he has a couple of issues with Darlington's model, but "we have made tremendous progress in the science. We're all working to improve all of this stuff."
The California low carbon fuels standard is another question, Tyner said, stating that "it's really tough to create a policy that puts millions of dollars on every percentage point on every different type of fuel." Measurement becomes absolutely critical, he said, adding that "I don't think we're going to get there," to a point where we can be absolutely certain of each percentage point.