Offshore wind conditions

Measuring wind at the North Sea

TNO carries out long-term meteorological measurements at the North Sea. The results help developers design their offshore wind farms in the most efficient way. New knowledge is constantly needed regarding wind behaviour in particular locations, and the forces it exerts on the structure and the blades. We carry out these measurements at three offshore platforms: Lichteiland Goeree (LEG), Europlatform (EPL) and production platform K13a. These are carried out using (laser-based) LiDAR measurement systems which provide measurements up to an altitude of 200 metres. This unique data is available on the WindOpZee.net website.

The data supports the business case for developers competing to build future offshore wind farms. Data from measurements can improve the predicted yield by a few percentage points, making financing more advantageous. In the near future, a new measuring location will be set up to further support the development of the 'North of the Wadden' wind farm zone.

DOWA: Dutch Offshore Wind Atlas

TNO, KNMI and the Delft-based company Whiffle have jointly compiled a wind atlas, called Dutch Offshore Wind Atlas (DOWA). It contains detailed information about the wind across the North Sea, at unprecedented level. DOWA provides wind speed and wind direction up to an altitude of 600m, at a spatial resolution of 2.5 squared kilometres and at every hour. DOWA wind information is available from 2008 onwards. Together with the wind measurements it provides a very good basis for developing offshore wind farms.

TNO has specific expertise of the wind conditions which may affect wind turbines and wind farms, and the Dutch Met Office contributes its own specialist knowledge using weather models. Whiffle has developed software which is able to calculate local wind information to an extremely high resolution.

Based on improved models and methodology, the new atlas provides more accurate wind information at a higher resolution and at altitudes of up to 600 metres. TNO has validated the atlas using accurate wind measurements from offshore meteorological masts, LiDARs on platforms, floating LiDARs, and from satellites and aircraft. This will enable a better understanding of the conditions which affect offshore wind energy, especially at higher altitudes.