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.

Biomass is an important renewable energy resource for NFS lands. While not included in the original 2005 NREL study, it was recently studied and documented by the NREL in U.S. Renewable Energy

Technical Potentials: A GIS‐Based Analysis (NREL 2012c). The Biopower Technical Strategy Workshop Summary Report (DOE EERE 2010) was also consulted in developing the screening criteria for this study.

The majority of the resource‐specific screening criteria used in this study were based on Argonne’s recent work on the Eastern Interconnection States’ Planning Council’s (EISPC) Energy Zones Study. The project is a collaboration between EISPC, Argonne, NREL, and Oak Ridge National Laboratory (ORNL) to create a web‐based interactive mapping and modeling tool designed to identify areas most suitable for clean energy resource development, and ultimately facilitate the analysis and planning of energy zones. During the study, biomass energy subject matter experts assisted in identifying and collecting the

needed data and designing the suitability models. Approaches used in the EISPC study are consistent with the other documents. The final report for the EISPC’s Energy Zones Study project, and documents detailing the EISPC data sources and model design are available on the EISPC website (Argonne 2013, EISPC 2012,b).

The seven criteria used for biomass energy were as follows:

 2012 county‐level biomass estimates for logging residues and forest thinning from the Bioenergy Knowledge Discovery Framework (KDF) Billion‐Ton Update ($60/dry ton price assumption).

 Topographic slope less than or equal to 12%.

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

 Outside of areas with population density greater than or equal to 500 people per square mile.

 Outside of open water, woody wetlands, and herbaceous wetlands National Land Cover Database land cover types.

Outside of protected areas, including USFS Inventoried Roadless Areas; USFS Special Designated Areas; 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.

 Outside of floodplains.

A minimum threshold for biomass resources has not been generally established, and in this study biomass resources were divided into 3 quantiles so that each category represents one‐third of the area, denoted as low, medium, and high suitability. Biomass data for Alaska of comparable and sufficient quality as that for the contiguous states are not yet available. Alaska has considerable biomass energy resources that are promising for power production, so this is an important area for future analysis. Unlike the other energy resources in the study, biomass can be transported from the source to a power plant by road, railroad, barge, or a combination of these routes, though it is expensive to transport it long distances. This analysis combines the resource availability with a limited transport distance,

assuming the power plant would be located in a suitable location close to a high level of biomass resources. A power plant using the biomass resources might not be located on NFS lands, but that assumption was made in this study.

Biomass resources are also used to produce liquid fuels and heat. This study concentrates on biomass used for electrical power production for consistency with the other technologies, and the criteria are designed to address power plants which use biomass for their primary fuel, or for co‐firing with other fuels.