This is a brief description of studies that exemplify the methods and approaches that have been developed and used by Oak Ridge National Laboratory (ORNL) researchers in conducting integrated assessments. See the complete list of Integrated Assessment Briefs to find out more about ORNL's efforts in integrated assessment. Contact Mike Farrell ( for more information.

Renewable Biomass Energy: Understanding Regional Scale Environmental Impacts

Relative shifts in evapotranspiration, erosion, nitrate in runoff, and phosphorous fertilizer applications are shown with increasing acreage in switchgrass production. Each line represents a single subregion.

What are the environmental implications of converting millions of acres of farmland to production of biomass energy? What kinds of models will be most useful in predicting environmental changes induced by energy crop production?

Probable environmental effects of growing energy crops are examined at a regional scale. The approach takes into account both economic and environmental factors. The approach is to analyze, at a county level, the probable impact of switchgrass production on erosion, evapotranspiration, nitrate in runoff, and phosphorous fertilizer in two multi-county subregions within the Tennessee Valley Authority (TVA) service region.

Results show that the adoption of switchgrass production will have different impacts in each subregion as a result of difference in the initial land use and soil conditions in the subregions. Erosion, evapotranspiration, and nitrate in runoff are projected to decrease in both subregions as switchgrass displaces the current crops. Phosphorous fertilizer applications are likely to increase in one subregion and decrease in the other because of initial differences in the types of conventional crops grown in each subregion. Overall, these changes portend an improvement in water quality in the subregions with the increasing adoption of switchgrass.

Graham, R. and M. Downing. 1993. Renewable biomass energy: Understanding regional scale environmental impacts. pp. 1566-1581. In Proceedings of the First Biomass Conference of the Americas. Vol. II. National Renewable Energy Laboratory, Golden, Co.

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Integrated Assessment Briefs. 1995. ORNL/M-4227. Oak Ridge National Laboratory, Oak Ridge, TN.