New wind energy resource potential estimates for the United States

Wind energy currently supplies about two percent of US electricity demand but has the potential to supply much more. To help set priorities for both federal and state policy initiatives to expand the use of this non-polluting energy resource, accurate information concerning the potential for wind energy development in each state is required. The National Renewable Energy Laboratory (NREL) and AWS Truepower, LLC, have collaborated to produce the first comprehensive new state-level assessment of the onshore wind resource potential since 1993. The new estimates are reported here.

The estimates are based on high-resolution maps of predicted mean annual wind speeds for the contiguous 48 states developed by AWS Truepower. These maps, which are defined at a horizontal spatial resolution of 200 m and heights ranging from 60 m to 100 m above ground, were created with a mesoscale-microscale modeling technique known as MesoMap®. (The US Department of Energy and NREL provided critical support for the mapping of some 35 of these states through the Wind Powering America initiative; the rest were mapped independently by AWS Truepower.) AWS Truepower subsequently merged the maps and adjusted them to reduce errors through a bias-correction procedure involving data from over 1000 masts throughout the country. The resulting adjusted mean speeds are estimated to have a standard error of 0.35 m/s relative to the true long-term values at each grid point. Finally, AWS Truepower applied a national database of 10 years of simulated hourly wind speed, direction, temperature, and other weather parameters (the windTrends® data set) to estimate the mean annual average plant output for a large (1.5-3 MW class) wind turbine at each point on the map. The power curve for the turbine was created by averaging the power curves for three commercially available IEC Class 2 turbines. The result of this process was a high-resolution map of the estimated annual gross capacity factor (average output divided by rated capacity, unadjusted for losses) for this hypothetical turbine at heights of 80 m and 100 m above ground.

NREL used the capacity factor maps to estimate the windy land area, wind energy potential in megawatts of rated capacity, and annual wind energy generation in GWh for each state in various capacity factor ranges. Excluded from the totals are lands that are unlikely to be developed due to environmental protections, incompatible land use, and other factors. These estimates should be regarded as an upper bound on the total developable potential in each state, as various constraints (such as access to transmission) will prevent development of all available land.

The presentation will also include the key findings of this wind potential study and provide tips on how to best use and interpret the resultant wind energy resource maps and estimates of wind energy potential that are available on NREL's website.