Wind Potential Capacity
The wind potential capacity maps show land area with a gross capacity factor1 of 35% and higher, which may be suitable for wind energy development. AWS Truepower LLC produced the wind resource data with a spatial resolution of 200 m, which was binned into 20-km grid cells. Map shading shows the amount of potentially developable area within each 20-km cell: the darker the color, the larger the potentially developable area within each cell. Areas that are excluded from development by law, such as wilderness areas and national parks, and other areas unlikely to be developed, such as urban areas and water bodies, have also been excluded. Wind potential maps are provided for a current 2014 industry standard wind turbine installed on a 110-m tower, which represents plausible current technology options, and a wind turbine on a 140-m tower, which represents near-future technology options.
Site evaluation for wind projects should be coordinated with appropriate authorities and should consider potential effects on local resources and land uses, including but not limited to impacts on wildlife, sound, visual, radar, aviation, safety and local public acceptance. Various federal agencies have authorities relating to the siting and permitting of wind plants, depending on the location and resources that might be affected. For example, potential impacts to air traffic and military missions are evaluated by the Federal Aviation Administration (FAA) and U.S. Department of Defense Siting Clearinghouse through the FAA's airspace obstruction evaluation process. Potential impacts to migratory birds or endangered species are evaluated with the U.S. Fish and Wildlife Service. Other federal agencies that may have a role include, but are not limited to, the U.S. Army Corps of Engineers for projects impacting wetlands and waterways and the Bureau of Land Management or U.S. Forest Service for projects on federal lands. Similar state, tribal, and local agencies may also have jurisdiction.
Another way to understand how new technologies affect the potential developable land area is with a summary chart. Charts showing the wind potential capacity above a given gross capacity factor at various heights are available for the contiguous United States and for states.
In addition, NREL estimated the land area and wind potential capacity in various capacity factor ranges for each state using the Wind Site Assessment Dashboard (https://dashboards.awstruepower.com) from AWS Truepower LLC. This table lists the estimates of land area with a gross capacity of 35% and greater from development of the "available" land area after exclusions. In the table, "installed capacity" refers to the potential megawatts of rated capacity that could be installed on the available land area. NREL reduced the wind potential estimates by excluding areas unlikely to be developed (see Wind Resource Exclusion Table for more detail).
These maps and wind potential estimates resulted from a collaborative project between NREL and AWS Truepower LLC. The U.S. Department of Energy's WINDExchange initiative supported these mapping efforts.
1. NREL assumed a 35% gross capacity factor, a measure of total energy produced compared to the wind turbines' rated nameplate capacity over a year, as the minimum energy production that may be suitable for development. Assuming 15% losses and a 35% gross capacity factor results in a net capacity factor of nearly 30%, which is the long-term historical average fleet-wide net capacity factors in the United States. (Wiser and Bolinger 2014)