Wind Measurement for Site Assessment
The taller the wind turbine is, the higher is the wind performance and the better is the return on investment of the wind farm.
The installation of a complete, state-of-the-art measuring system at one or several significant locations on a potential site gives the best assessment of the site’s wind conditions and helps to determine its suitability for a wind farm.
Measuring the wind speed (velocity) with anemometers
Measuring the wind speed (velocity) with anemometers is critical for the evaluation of a site’s wind energy potential. During wind measurement campaigns wind statistics are gathered according to the wind atlas method and are cleared of any topographical influences.
The preparation of wind statistics usually lasts for at least 12 months. During the campaign, wind measurement data is collected continuously at regular intervals. Weather conditions vary from season to season and from one year to the next.
An accurate wind site assessment requires the comparison of new detailed wind measurement data with long-term meteorological data, e.g., data from nearby weather stations. Both must be analyzed together to determine whether the site is suitable for the erection of a wind farm.
The quality of weather station data does not have to be to the same standard as the wind measurement data, but it is important that both sites are comparable and that the external data is checked for reliability, e.g., the weather station has not moved during the relevant period.
Assessment of wind direction
In addition to the assessment of wind speed, the assessment of wind direction and its allocation is required. This parameter is measured with wind vanes. Assessing wind direction and allocation helps to avoid sheltering effects within the wind farm.
An analysis of the surrounding topography and ground consistency should also be made and taken into account for the assessment calculations. Although less crucial, values such as air density, air pressure and humidity should be considered as well.