NREL Finds U.S. Wind Energy Potential Larger than Previously Estimated
March 3, 2010
The maximum potential to generate wind power in the United States is more than three times greater than previously estimated, according to a new study by DOE's National Renewable Energy Laboratory (NREL). The new analysis, developed in collaboration with AWS Truewind, LLC, is based on updated computer models and examines the wind potential at wind turbine hub heights of 80 meters and 100 meters. These higher hub heights reflect current and future models of wind turbines, and are partially responsible for the higher numbers. Previous studies were performed at hub heights of only 50 meters, which were more representative of commercial wind turbines in the early 1990s. The new study also has a spatial resolution of only 200 meters, compared with the previous national study, which had a resolution of 25 kilometers. The updated model filtered out urban areas, water areas, and lands such as parks that could not be developed for wind power. It represents the maximum amount of wind power that could be reasonably developed in the contiguous United States.
The new study found that the U.S. wind energy potential depends greatly on turbine hub heights and the capacity factor that developers are willing to accept. The capacity factor is the amount of power produced per year divided by the amount of power that would be produced if the wind turbine operated at full capacity all the time. Capacity factors for today's wind power plants are typically around 30%. For a 60-meter hub height, the study found that 10,459 gigawatts (GW) of wind power could achieve a 30% capacity factor, generating nearly 37 million gigawatt-hours (GWh) of electricity per year. As noted by the American Wind Energy Association (AWEA), the previous government survey of U.S. wind resources, published by DOE's Pacific Northwest National Laboratory in 1991, pegged U.S. wind potential at 10.8 million GWh. The new study still found a huge potential at a 40% capacity factor, with 5,577 GW of wind capacity generating nearly 22 million GWh of wind power per year. And at a 100-meter hub height and 30% capacity factor, the potential is even higher, with 12,125 GW of wind capacity generating 44.7 million GWh per year of wind power, or about 20% more than at the 80-meter hub height. Several states also benefit from the updated figures, as Indiana, Ohio, and Oregon moved onto the list of the top 20 windiest states for the first time. To put the figures in perspective, the current U.S. installed wind power capacity is only 35 GW. See the wind maps and the table of results (Excel 127 KB) on DOE's Wind Powering America Web site, as well as the AWEA press release.