James Madison University

Wind Measurement

The wind resource at a particular location is characterized by two measures — wind speed and wind direction. Using these two measures, the feasibility of installing a wind turbine can be determined. As a general rule, a good wind resource is considered an average annual wind speed of 5m/s or above at approximately 100ft above ground level. Installing an appropriately-sized wind turbine at this wind speed will create a more likely scenario for a reasonable payback period.

Meteorological (MET) Towers — Program Summary

In 2001, the Center for Wind Energy was selected to administer the State-Based Anemometer Loan Program (SBALP) under a grant from the Virginia Department of Mines, Minerals and Energy (DMME), with assistance from the National Renewable Energy Laboratory (NREL). SBALP was established by the U.S. Department of Energy's (DOE) Wind Powering America Initiative. The program was expected to spur the development and use of wind power in Virginia by helping potential wind turbine users to quantify their wind resource.
To administer the SBALP program over the years, the Center for Wind Energy has received a number of 20-meter, 34-meter and 50-meter meteorological towers. These towers were loaned to landowners giving them the opportunity to measure their available wind energy resource while providing wind data to the Commonwealth and NREL.
While the Sbalp program is not supported at this time, CWE has installed met towers at a several Virginia schools supported by the Wind for Schools program. Interested schools can contact us for further details.

Sbalp meteorological tower data is available for download from our interactive maps.

Off-the-shelf Data Equipment

If you decide to measure your own wind resource, we are happy to assist you in siting your equipment to ensure that the data is adequate for wind assessment and turbine size suggestions. We can also assist you with data analysis from your weather station. Below are a few suggestions of various types of weather monitoring equipment. The key things to look for are an anemometer and a wind vane, as well as the ability to log and archive your data and that it is easily accessible.

We have one of each of these systems installed at the Small Wind Training and Testing Facility on the JMU campus.  We are happy to host a visit to learn more about how these systems work and the pros and cons of each.  Feel free to contact us for more information or to set up a visit.

Wind Profilers

SoDAR

SoDAR (Sonic Detection And Ranging) is a method of measuring wind speed and direction by emitting sound waves and receiving the scatter after they have interacted with the atmospheric turbulence caused by the wind. This technology is important because SoDAR apparatuses are more easily deployed—the only siting requirements are level ground and an unimpeded view of the sky from the device.

  • Triton
    The Triton SoDAR unit is produced by Second Wind. It is a low-power device, operating at about 7 watts that are generated by a photovoltaic cell mounted on the unit. The wind data is sent to a personalized SkyServe® web portal. It is capable of taking measurements from 40 to 200m. It is also capable of detecting wind speeds ranging from 0 to 25 m/s. The physical area needed to install the unit is about 6 m2. More information can be found on secondwind.com.
  • ASC (Atmospheric Systems Corporation)
    The ASC 4000we SoDAR unit is a portable wind measurement unit. It is capable of taking measurements from 30 to 200m, and detecting wind speeds ranging from 0 to 45 m/s. This apparatus uses approximately 25 watts of power. The physical area needed to install this unit is about 11 m2. More information can be found on minisodar.com.

Both the Triton and ASC SoDAR units are used by the CWE for student projects and training. Periodically these units are deployed for special projects. Contact us with your project idea.

LiDAR

LiDAR (Light Detection And Ranging) is a method of measuring wind speed and direction by emitting light particles and receiving the backscatter after they have interacted with the atmospheric turbulence caused by the wind.

There are two types of LiDAR – side-canning and profiling.  Profiling LiDAR measures wind speed and direction at a single location – looking straight up.  Side-scanning LiDAR can measure wind speed (and direction?) looking sideways at points kilometers away.  This has an obvious benefit for measuring offshore winds without the need for an offshore location.

  • SpiDAR
    SecondWind manufactures a LiDAR called SpiDAR which is a mobile wind resource measuring device. The measurement range is from 30 to 200m with 10 programmable heights. Wind speed range is from 0 to 70 m/s. This apparatus uses an average of about 35 watts of power. More information can be found on secondwind.com.