Wind Energy Developers

North Wind Measurement can provide complete, turnkey assessment at most sites in 3-4 months. Met towers are available from 30 to 50 meters.

We use a proprietary system of comparing your test site with nearby long-term/real-time sites (Airports, NOAA sites, etc) to produce a set of equations that relate your test site resource to the reference site. We then develop a set of sector-based equations that allow us to calculate, for each wind direction, the relationship between the test and reference sites.

For example, at 75 to 105 degrees (90 deg, East) the equation might be:

Test₉₀ = 1.1 x Ref₉₀ + 0.5

So, if
Ref₉₀ = 10.0
Test₉₀ = 10.0 x 1.1 + 0.5
Test₉₀ = 11.5

Below is an example of a site on the Leelanau Peninsula.

Data was correlated between Grand Traverse Lighthouse (GTLM4) and a nearby test site. The first 37 days of data showed excellent hourly correlation for all sectors. (R² from 0.72 to 0.98). Below is the NNW sector (300 – 330 degrees):

This allows us to calculate the test site windspeed vs the GTLM4 windspeed in this sector for any historical period.

Depending on the proximity of the reference site, the correlation will be performed hourly, half-day or daily.

This set of equations can then be used to “back calculate” the windspeeds at your test site for 5-10 years based on the reference site’s historical data.

This method can also be used to quickly assess several sites in a wind farm array. Several 40m towers can be deployed at prospective sites and correlated to the main 50m, 60m or SODAR site. In most cases, this is less expensive and more accurate than a CFD analysis.

We use NRG #40 anemometers and 200P wind vanes (RM Young or others are available on request). We also log temperature and pressure to calculate air density at each logging interval.

Our software can also account for tower shadow effects and calculate true windspeed between paired anemometers.

Measurements and processes can be certified to COWI or ISO standards.