NREL is a national laboratory of the U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy, operated by the Alliance for Sustainable Energy, LLC.

New Wind Energy Resource Potential 

Estimates for the United States

Dennis Elliott (NREL)

Marc Schwartz, Steve Haymes, 

Donna Heimiller, George Scott 

(NREL)

Michael Brower, Erik Hale, Bryon 

Phelps (AWS Truepower, LLC)

Second Conference on Weather, 

Climate and the New Energy 

Economy

January 27, 2011

91st Annual Meeting of the 

American Meteorological Society

Seattle, Washington

NREL/PR-5500-50439
NATIONAL RENEWABLE ENERGY LABORATORY

U.S. Wind Mapping Rationale

Provides accurate information 

about the wind resource in each 

state

• For federal and state policy 

discussion, analysis, and 

implementation

• To support the 20% wind future

• To facilitate wind prospecting 

• To support state, regional, and 

national wind integration analyses

Validates wind resource maps

• Essential to ensure stakeholder 

confidence in accuracy of map 

estimates

Supports the Program’s mission 

of eliminating barriers to wind 

energy.
NATIONAL RENEWABLE ENERGY LABORATORY

Technical Approach: Wind Mapping & Validation

Produce maps based on: 

• Numerical modeling (AWS Truepower) 

and adjustments

• Empirical and analytical methods

• 1 km2 or finer horizontal-resolution 

wind resource maps

Validate preliminary maps using public 

and private wind measurement data

Develop and validate maps at 50-m 

height for 39 states

Update mapping at 80- & 100-m heights 

for 48 contiguous states

• Develop wind potential estimates (net 

of exclusions)

Publish on DOE’s Wind Powering 

America (WPA) Web site
NATIONAL RENEWABLE ENERGY LABORATORY

U.S. Wind Mapping and Potential: 50-m Height

50-m wind mapping 

(2001-2009) 

• Culmination of long-term 

project that began in 

2001; jointly funded by 

states and DOE/WPA

• Comprehensive validation 

of WPA maps using 

available measurement 

data

• Incorporated state maps 

by others to produce a 

national wind map 

(“patchwork quilt” evident 

in some regions) 

• 50-m wind potential 

estimates to support U.S. 

20% wind scenario study
NATIONAL RENEWABLE ENERGY LABORATORY

U.S. Wind Mapping and Potential: 80- & 100-m Heights

80- & 100-m mapping and potential estimates (2009-2010) 

• New products for contiguous United States and each state developed through a 

collaborative project with AWS Truepower

• Annual average wind speed maps at 80- and 100-m heights

• NREL validated 19 selected state maps with tower measurement data from 300+ locations

• Wind potential estimates at 80 m and 100 m based on modeled wind turbine capacity 

factor (CF) data – CF example: 1-MW rated turbine at 30% CF = an average of 300 kW

• Posted new products to WPA Web site (broke all-time DOE/EERE records for most hits)

• Hosted national Webinar to discuss new products and methodology

• Responded to many media and stakeholder requests about the new products
NATIONAL RENEWABLE ENERGY LABORATORY

80-m United States Wind Resource Map 
NATIONAL RENEWABLE ENERGY LABORATORY

AWS Truepower’s MesoMap Process

Geophysical

Data Mesoscale

Simulations

(MASS)

Microscale

Simulations 

(WindMap)

Wind Maps

Met

Data

Databases

Validation

full equations 

of motion

dynamic

366 days from

15 years

2.5 km resolution

mass-conserving

adjusts for local

terrain and roughness

200 m resolution

global reanalysis

rawinsonde

surface met data

topography

roughness

vegetation greenness

sea temps

comparisons

with met data

adjustments

error estimates
NATIONAL RENEWABLE ENERGY LABORATORY

AWS Truepower’s Estimation of Plant Output

For each point, wind speed 

distribution created from 12 

years of weather simulations 

(windTrends)

Then gross turbine output 

calculated for a generic IEC 

Class 2 turbine power curve, 

corrected for air density

0%

2%

4%

6%

8%

10%

12%

14%

0 2 4 6 8 10 12 14 16 18 20 22 24 >25.5

Wind Speed (m/s)

Frequecny

Speed Freq

Weibull Freq

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

0 5 10 15 20 25 30

Capacity Factor

Speed (m/s)

Composite IEC Class II Power Curve
NATIONAL RENEWABLE ENERGY LABORATORY

Development of Wind Potential Estimates

• AWS Truepower produced a national dataset of estimated CF (not 

adjusted for losses)

– Spatial resolution of 200 m

– Heights of 80 m and 100 m

– Land-based areas only (no offshore), 48 contiguous states

• NREL used the CF data to estimate the land area and wind potential for 

each state

– Windy land defined as areas with >= 30% CF, which are generally considered to 

be suitable for wind energy development 

– Areas with CF >=30% have mean annual wind speeds of about 6.4 m/s and greater

– Excluded sensitive environmental lands and incompatible land-use areas

– For wind potential, assumed 5 MW/km2 of installed nameplate capacity

Why use CF and not Power Class to produce wind potential estimates?

CF is representative of power output from large wind turbines.

Power class is representative of theoretical energy in the wind.
NATIONAL RENEWABLE ENERGY LABORATORY

National Exclusion Map
NATIONAL RENEWABLE ENERGY LABORATORY

Wind Resource Potential at 80 & 100 m - United States

Capacity factor (CF) example: 1-MW rated turbine at 30% CF = an average of 300 kW
NATIONAL RENEWABLE ENERGY LABORATORY

Tables of State Wind Potential

Estimates of Windy Land Area and Wind Energy Potential by State

For Areas >=30% Capacity Factor at 80 m

Installed Capacity – assumes 5 MW/km2 of available windy land area

Annual Generation – annual wind energy generation that could be produced from the installed capacity

(Tables are also available for other CF categories and heights) 
NATIONAL RENEWABLE ENERGY LABORATORY

Comparison of State Wind Maps and Potential Graphs

Arizona

Ohio

North Dakota
NATIONAL RENEWABLE ENERGY LABORATORY

Wind Potential – Key Findings

U.S. wind potential from areas with CF>=30% is enormous

• At 80 m, almost 10,500 GW capacity

• At 100 m, 12,000 GW capacity

Most of the wind potential comes from windy central regions, but many 

eastern and western states have significant wind potential

• 35 states with >1,000 MW capacity at 80 m

• 38 states with >1,000 MW capacity at 100 m

For higher CF ranges at 80 m, U.S. wind potential is still very large

• CF>=35%, >8,000 GW and 28 states >1,000 MW 

• CF>=40%, >5,500 GW and 19 states >1,000 MW

– Available at: http://www.windpoweringamerica.gov/wind_maps.asp

Top 10 states with CF >=30% at 80 m

• By Installed Capacity: TX, KS, MT, NE, SD, ND, IA, WY, OK, NM

• By Annual Generation: TX, KS, NE, SD, MT, ND, IA, WY, OK, MN
NATIONAL RENEWABLE ENERGY LABORATORY

Proposed Next Steps

• Develop new 80- and 100-m wind resource maps and potential estimates 

for Alaska and Hawaii

• Update national maps to include entire United States

• Incorporate new offshore maps as they become available

• Develop maps at 30-m height for small wind turbine industry

• Initiate comprehensive program to validate 80- and 100-m maps

• Review and update exclusion methodology

• Identify key areas for new measurements and updated assessments