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.

NREL’s analysis included six criteria for concentrating solar power:

 Direct normal solar resource potential greater than or equal to 7 kWh/m2/day.

 Topographic slope less than or equal to 1%.

 Within 25 miles of transmission lines at least 69 kV in capacity.

 Within 25 miles of roads (down to rural local road classes) or railroads.

 Outside of USFS Inventoried Roadless and Special Designated Areas.

 Contiguous land parcel size of at least 40 acres.

The second phase of the analysis included the additional screening factors listed below:

 Within 20 miles of surface water sources with flow of at least 64,500 gpm.2

 Outside of wetlands and floodplains.

 Outside of open water, vegetated, forested, urban or developed land cover types.

 Outside of protected areas, including USFS experimental forests; FWS designated critical habitat; national scenic and historic trails; wilderness study areas; wild and scenic rivers; wilderness areas; national monuments; and national conservation areas.

The scope of this report includes Alaska. However, CSP data of comparable and sufficient quality as that for the contiguous states are not yet available. Available low‐resolution CSP data have insolation values well below the threshold set for this analysis, as would be expected for the northern latitudes of Alaska.