Back in my school years, I learned that agriculture involved production of food, feed and fiber. These days of course, we’ve added production of energy to the list. And according to a recent study from the University of Montana, without significant policy change, food, feed and fiber could nearly drop off the list entirely.
The study, titled “Bioenergy Potential of the United States Constrained by Satellite Observations of Existing Productivity,” was published recently in Environmental Science & Technology, a journal of the American Chemical Society. Results of the study illustrate the need to develop alternative raw materials for biofuel production, rather than grain which is today’s primary feedstock, and to adjust our expectations.
The researchers point out that the Energy Independence and Security Act (EISA) of 2007 aims to increase annual U.S. biofuel production by more than three-fold, from 40 to 136 billion liters of ethanol by 2022.
In their study, they used satellite-derived net primary productivity (NPP) measurements of vegetated land in the United States to estimate primary bioenergy potential. Based on their data, the researchers conclude that although EISA energy targets are theoretically achievable, meeting these targets with current technology would require either an 80 percent displacement of current crop harvest or the conversion of 60 percent of rangeland productivity. This shift, they note, would dramatically reduce U.S. agriculture’s volume of food production while increased farming could lead to more polluted freshwater and accelerate global climate change.
“We learned that gaps exist in the ability to establish realistic targets for biofuel production, which the law fills with assumptions about technology developments and the availability and productivity of farmland,” says lead author W. Kolby Smith, a doctoral student in UM’s Numerical Terradynamic Simulation Group (NTSG), in a news release.
Another of the researchers, Steve Running, NTSG director and Regents Professor of Ecology, stresses the need for alternative energy sources and realistic bioenergy 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. Additionally, bioenergy may be more efficiently used for electric power production instead of liquid fuels.”