In 2005, the National Renewable Energy Laboratory (NREL) completed an assessment of the potential for solar and wind energy development on National Forest System (NFS) public lands managed by the US Department of Agriculture, U.S. Forest Service (USFS). This report provides an update of the analysis in the NREL report, and extends the analysis with additional siting factors for solar and wind energy. It also expands the scope to biomass and geothermal energy resources. Hydropower is acknowledged as another major renewable energy source on NFS lands
however, it was not analyzed in this project primarily because of the substantially different analysis that would be needed to identify suitable locations. Details about each renewable energy production technology included in the study are provided following the report introduction, including how each resource is converted to electrical power, and examples of existing power plants. The analysis approach was to use current and available Geographic Information System (GIS) data to map the distribution of the subject renewable energy resources, major siting factors, and NFS lands. For each major category of renewable energy power production, a set of siting factors were determined, including minimum levels for the renewable energy resources, and details for each of the other siting factors. Phase 1 of the analysis focused on replicating and updating the 2005 NREL analysis, and Phase 2 introduced additional siting factors and energy resources. Source data were converted to a cell-based format that helped create composite maps of locations meeting all the siting criteria. Acreages and potential power production levels for NFS units were tabulated and are presented throughout this report and the accompanying files. NFS units in the southwest United States were found to have the most potentially suitable land for concentrating solar power (CSP), especially in Arizona and New Mexico. In total, about 136,032 acres of NFS lands were found potentially suitable for CSP development, potentially yielding as much as 13,603 megawatts (MW) of electricity, assuming 10 acres per MW. For photovoltaic solar power (PV), the top NFS units were more widely distributed than CSP. Notably, more than 150,000 acres in Comanche National Grassland in Colorado were found to be potentially suitable for PV development, accounting for more than 25% of the potentially suitable NFS lands combined. In total, about 564,698 acres of NFS lands were found potentially suitable for PV development, potentially yielding as much as 56,469 MW of electricity, assuming 10 acres per MW. NFS units most suitable for wind power are concentrated in the northern Great Plains. In total, about 3,357,792 acres of NFS lands were found potentially suitable for wind development, potentially yielding as much as 67,156 MW of electricity, assuming 50 acres per MW. Of that area, 571,431 acres (11,429 MW) are located within the Bankhead-Jones Farm Tenant Act Land in Montana. NFS lands in Alaska have considerable wind resources, but other siting factors eliminated almost the entire area. The southwest coast of Chugach National Forest, near Seward, Alaska, maintains the majority of the remaining acreage. NFS units with highly suitable biomass resources are located from Idaho to Louisiana. In total, about 13,967,077 acres of NFS lands are potentially highly suitable for biomass from logging and thinning residue development. Of that, 1,542,247 acres is located in Fremont-Winema National Forest in Oregon. Not surprisingly, most NFS units have at least some level of potentially suitable biomass resources. In general, biomass resources such as these could significantly offset consumption of coal and petroleum-based fuels. NFS units deemed potentially highly suitable for enhanced geothermal system (EGS) development were distributed widely from California to Virginia, accounting for some 6,475,459 acres. Mark Twain National Forest in Missouri has the largest area of all the NFS units, with 900,637 acres. While more rigorous studies are needed for siting geothermal plants, especially those regarding the geological characteristics of specific sites, current results suggest a significant potential for geothermal power generation within many NFS units. The first phase of analysis for solar and wind resources sought to replicate the 2005 NREL methodology using updated source data.1 The total acres meeting the criteria for all NFS lands were lower in the updated assessment compared to the 2005 NREL analysis because the earlier assessment included all land that fell within NFS administrative boundaries rather than only NFS-managed land within them. Acreages were again lower when refined screening factors were added, as would be expected. These remaining areas are of greater interest because they adhere to a broader set of criteria. As this study illustrates, GIS data availability for renewable energy resources and major screening factors has reached a point where national screening level studies can effectively assess the levels and spatial distributions for potentially renewable energy technology development. More detailed siting studies, land use planning, and environmental compliance assessments are essential before individual projects can be permitted and built. However, this study can serve to inform resource managers and planners of where these technologies are most likely to be investigated and proposed
help prioritize efforts to continue informed and sustainable development of renewable power generation within the United States
and help characterize the role of the USFS in this arena. The authors caution against using the areas reported in the results as a final and definitive estimate of suitability for these technologies. The analysis is most useful for determining locations that should be examined more fully, and for identifying regional and national trends.