Potential Suppy and Cost of Biomass from Energy Crops in the TVA Region
Potential Suppy and Cost of Biomass from Energy Crops in the TVA Region |
The economic and supply structures of energy crop markets have not been established. Establishing the likely price and supply of energy crop biomass in a region is a complex task because biomass is not an established commodity as are oil, natural gas, and coal. In this study, the cost and supply of short-rotation woody crop (SRWC) and switchgrass biomass for the Tennessee Valley Authority (TVA) region--a 276-county area that includes portions of 11 states in the southeastern United States--are projected. Projected prices and quantities of biomass are assumed to be a function of the amount and quality of crop and pasture land available in a region, expected energy crop yields and production costs on differing soils and land types, and the profit that could be obtained from current conventional crop production on these same lands. Results include the supply curves of SRWC and switchgrass biomass that are projected to be available from the entire region, the amount and location of crop and pasture land that would be used, and the conventional agricultural crops that would be displaced as a function of energy crop production.
Finally, the results of sensitivity analysis on the projected cost and supply of energy crop biomass are shown. In particular, the separate impacts of varying energy crop production costs and yields, and interest rates are examined.
The goal of this project was to provide the Tennessee Valley Authority (TVA) with information with which to evaluate land base capabilities in terms of supplying sufficient biomass from energy crops at a price that would allow it to compete with coal. Specifically, the objective of this research was to determine how much biomass could be grown, where it could be grown, how much it would cost to produce, and what the price would be.
The potential land base for energy crop production was defined by TVA and encompassed the 201 TVA service counties plus 75 additional counties that were within a 75-mile radii of existing TVA coal-fired power plants. The energy crops considered in this analysis were SRWCs (short-rotation woody crops) and switchgrass. SRWCs are trees grown at tight spacings with weed control and some fertilizer application. The wood and bark of the boles and branches are harvested at 6- to 10-year rotations, whereas the leaves, stumps, and roots remain on the site (Wright et al. 1992a). A variety of hardwood tree species (hybrid poplar, sweetgum, sycamore, and black locust) was considered in the analysis. Switchgrass (Panicum varigatum) is a native perennial tallgrass-prairie species. It is a C4 plant and a bunchgrass. Switchgrass can take several years to become established. Stands are ready for harvest during their second growing season and annually thereafter. Switchgrass is harvested and baled like any other hay crop and, like other grasses, provides good erosion control. For maximum production, it requires some fertilizer application. Four production scenarios were examined in the analysis: (1) SRWC production on agricultural land, assuming current expected SRWC and conventional crop yields; (2) switchgrass production on agricultural land, assuming current expected switchgrass and conventional crop yields; (3) SRWC production on agricultural land, assuming current conventional crop yields and a 25% in SRWC yields; and (4) switchgrass production on agricultural land, assuming current conventional crop yields and a 25% increase in switchgrass yields.
This report was prepared by the Biofuels Feedstock Development Program, Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, managed by Martin Marietta Energy Systems, Inc., under contract DE-AC05-84OR21400 with the U.S. Department of Energy. Publication No. 4306, ESD, ORNL.
File created: October 21, 1996; Last updated: |