National Renewable Energy Laboratory

Wind Research

Site Wind Resource Characteristics

A graphic showing the location of National Wind Technology Center and its wind power class 2. Click on the image to view a larger version.

This graphic shows the wind power class at the National Wind Technology Center. You can view a larger version or download a printable copy (PDF 355 KB) Download Adobe Reader.

The National Wind Technology Center (NWTC) is on the Great Plains just miles from the Rocky Mountains. The site is flat and covered with short grasses. The terrain and lack of obstructions make the site highly suitable for testing wind turbines. Take a tour of the NWTC and its facilities to have a better understanding of its location and layout.

Another prime feature of the NWTC is the strong directionality of the wind — the prevailing winds are from 283° (at 50 m altitude). West of the NWTC is Eldorado Canyon. During the winter and spring, the canyon funnels the strong winds directly to the NWTC. Because of this strong directionality, it is easy to align test turbines and their anemometers perpendicular to the prevailing wind so that they will not interfere with each other; this alignment is generally north and south. The smaller turbines are located on the western or upwind side of the NWTC, while the larger turbines on the eastern or downwind side. This also prevents the wake of the larger turbines from affecting the tests on the smaller turbines. There is little if any effect on the larger turbines, as the prevailing wind passes through the smaller turbines. This spatial arrangement in combination with the strongly directional winds allow for multiple simultaneous tests at the NWTC. Because of the strong winter and spring winds, it is possible to gather enough data to define a power performance curve for most wind turbines. During the summer months the winds are light, and this allows for multiple days of maintenance and construction.

A chart showing the wind direction at the National Wind Technology Center by true degree on the x axis and percent of annual winds on the y axis. The chart spikes at 283°, illustrating that the predominant wind direction at the National Wind Technology Center is 283°. Click on the image to view a larger version.

The predominant wind direction at the National Wind Technology Center is 283°. You can view a larger version or download a printable copy (PDF 33 KB) Download Adobe Reader.

NWTC Wind Resource Characteristics

The average annual wind speed at the NWTC is 4.78 m/s (10.7 mph) at 50m.
The average power density at the NWTC is class 2 at 50 m.
Other characteristics of the wind resource at the NWTC at 50 m are:
- The wind direction mode is 283°.
- The IEC 1-year extreme wind is 38.2 m/s.
- The IEC 50-year extreme wind is 50.9 m/s.
- The 50- to 80-m shear exponent is 0.116.
- The turbulence intensity is 0.162 (computed when Vavg @ 80 m = 15 m/s).

Weather and Measuring the Wind

Current weather at the NWTC is displayed graphically and updated every minute. This weather is recorded from a meteorological tower on the western side of the NWTC. The times on the display are local (Mountain Time; GMT -7). The tower elevation is 1,855 meters (or 6,085 feet). Most of the NWTC site is downwind from the prevailing wind direction from the meteorological tower. The graphically displayed wind data is collected from 10-meters above ground level. More information is available about the meteorological tower or historical data.