Looking Down on the Future

Researchers employ satellites to analyze feedstock potential
By Kris Bevill | April 11, 2012

An analysis recently conducted by researchers at the University of Montana utilized NASA satellite data to evaluate the bioenergy potential of the U.S. and found that farmers would need to plant biofuel crops on 80 percent of cropland or on 60 percent of current pastureland in order to produce 36 billion gallons of biofuel by 2022 as required by the renewable fuel standard (RFS). The research also suggests, however, that if technologies to produce biofuel from waste feedstocks can be commercialized, currently available agriculture and forestry residues can be utilized to meet up to 80 percent of the total 2022 RFS mandate.

University of Montana doctoral student Bill Smith led the research and co-authored a paper on the findings, titled, “Bioenergy Potential of the United States Constrained by Satellite Observations of Existing Productivity,” which was published in the American Chemical Society’s Environmental Science & Technology journal. He says that while there have been multiple other studies conducted to evaluate the potential of bioenergy production in the U.S., the NASA algorithm used by his group, combined with other meteorological data focused on climate and water constraints, offers a more complete and accurate estimate of the landscape’s true production potential. “What’s different about our analysis is we have this explicit data for every square kilometer of the U.S., versus a lot of previous studies that use plot-level measurements that are fairly localized and have to use methods to extrapolate to different areas,” he says. “Some of those studies take into account biophysical factors (how they change across various landscapes), but others don’t do that as well, so you get a wide range of bioenergy potential estimates.”

The researchers made several assumptions when conducting the analysis. One assumption was that crop yields will remain at their current levels. Smith says this assumption was made based on previous studies that compared current productivity rates to natural productivity and found that nature produces the maximum potential. “Even with all of our current human management, agricultural productivity is generally less than natural productivity,” he says. “There are exceptions, usually because of irrigation. If you irrigate in an arid climate, you get production higher than what’s natural. [But] our thinking for things like irrigation and fertilizer were that these two factors, particularly in the U.S., are already nearing a point of unsustainability.”

Other researchers contributing to the project included co-authors Cory Cleveland, assistant professor of soil sciences at UM, and Steve Running, director of the university’s Numerical Terradynamic Simulation Group and Regents professor of ecology. While the results of the analysis indicated that the biofuels industry is on the right track by targeting residues for feedstocks, Running cautions that it is important to continue to focus on establishing attainable production goals. “While we encourage the appropriate use of agricultural residues, forest slash and beetle-killed trees for bioenergy, the nation needs realistic targets of the capacity for bioenergy production that would not compete with food production,” he says.  —Kris Bevill