FEW: Lifecycle analysis and the ethanol industry

By Rona Johnson | June 02, 2008
Web exclusive posted June 18, 2008 at 5:40 p.m. CST

Lifecycle analysis is a process that is constantly evolving as new issues come to the forefront such as indirect land use change, the value of ethanol coproducts and the impact of higher corn yields. The lifecycle analysis session at the International Fuel Ethanol Workshop & Expo addressed some of those issues although the panelists admitted that a lot of work needs to be done to determine the impact of indirect land use changes on lifecycle greenhouse gas emissions and just what should go into those calculations.

"Certainly lifecycle analysis is not a new concept or a new practice when it comes to biofuels, the [U.S.] Department of Energy and others have been looking at the greenhouse gas (GHG) and energy lifecycle of biofuels essentially since the industries began," said Jeff Cooper, director of research at the Renewable Fuels Association and the moderator of the panel. "It seems like up until now it has been quietly under the radar that this has been happening, but certainly understanding lifecycle analysis for biofuels has probably never been more important than it is now." That's because policy regimes, such as the Energy Independence & Security Act of 2007, are being developed that feature lifecycle analysis as regulatory mechanisms requiring several greenhouse gas thresholds be met for various classes of fuels to qualify for the renewable fuels standard (RFS). Also, California is developing a low-carbon fuel standard to reduce greenhouse gas emissions by 10 percent by 2020 which relies heavily on lifecycle analysis for regulation of the standard.

Cooper pointed out that the lifecycle analysis of biofuels is an evolving field and many questions have recently emerged about the impact of indirect land use changes, the impact of higher corn yields and how to allocate coproduct credits. "We at the RFA are advocating for sound science and not to rush to judgment on these issues," he said.

The researchers who developed the Biofuel Energy Systems Simulator Model have modified their product as questions are posed concerning lifecycle GHG emissions. "Last year I spoke about the model at this meeting and it was during the release of the first version," said Adam Liska, a postdoctoral research associate at the University of Nebraska, Lincoln. "Since then we've gone through three revisions based on external comments from interested users. There's been over 400 downloads of the model, of which 50 percent is within the ethanol industry, about 25 percent in academia and some governments who are interested in using the model as well."

Liska started his presentation with the definition of lifecycle GHG emissions from the EISA, which is "the aggregate quantity of GHG emissions (including direct emissions and significant indirect emissions such as from land use changes), related to the full fuel lifecycle, including all stages of fuel and feedstock production and distribution." Compared with gasoline the EISA requires that corn ethanol must reduce GHG emissions by 20 percent, cellulosic ethanol must reduce GHG by 60 percent and other advanced biofuels must reduce it by 50 percent.

At the moment, the U.S. EPA and the California Air Resources Board are developing methods and models to determine lifecycle GHG emissions for biorefineries that should be done by next year. In fact, Zia Haq, a chemical engineer for the DOE's Office of the Biomass Program and one of the session panelists, said a notice of proposed rule making will be published in September followed by a public comment period. He urged those in attendance at the workshop who are interested in the rule making to make sure they comment.

Liska believes that the BESS model is better than others currently available because it looks at many parameters other models don't. Liska, who described the BESS model for lifecycle analysis, pointed out that it's an analysis of individual biorefineries and crop production zones, assuming an ethanol plant is supported by the crop zone surrounding it. The model has three main input/output components: crop production, the ethanol biorefinery and a cattle feedlot for feeding the distillers grains coproduct. "There are three types of analysis in this model," he said. "There's the energy analysis, which is the lifecycle net energy yield and efficiency. There's a greenhouse gas emissions analysis, which is carbon dioxide and other trace emissions methanol and nitrous oxide and the global warming potential of those three combined." And then there's the metrics for research requirements - such as the crop production area, grain, water, and fossil fuels - that are needed to support the ethanol plant. The model doesn't yet include land use change. "We will assume that land use change will be one parameter which will be applied to all ethanol plants," he said. "This analysis is for looking at an individual plant not an aggregate for the whole industry."

Liska plugged the land use change number that was published in the journal Science into his calculations and it significantly raised the GHG emissions threshold for ethanol plants. "You guys are twice as greenhouse gas intense as gasoline so let's all go home, you're not getting your credit," he said. However, he cautioned that a lot of work still needs to be done to determine the value of land use change.

While researchers are looking for ways to determine the lifecycle emissions for biorefineries, Keith Kor, the general manager of Corn Plus LLLP, has been actively reducing the GHG emissions and fossil fuel use at the Winnebago, Minn., plant. By installing a fluid bed boiler to burn the corn syrup from the ethanol process, Kor has been able to reduce the plants natural gas consumption by 52 percent. That generates 40,000 carbon credits, which are sold on the Chicago Climate Exchange. The plant has also added another revenue stream by pelletizing it's ash into "prills" and selling it to the farmers for fertilizer. The addition of two 2.1 megawatt wind turbines produces half the electrical power requirements for the plant.

Kor pointed out, however, that with September corn at $7.63 per bushel and natural gas prices at $13.05 per British Thermal Units (MMbtu) as of June 18, the industry has to do more to become low-cost producers.