New laser technique to estimate power output from potential windfarm sites

Research Lead, Development Opportunity

Wind energy is currently the most important source of renewable energy in Europe, but it remains difficult and costly to assess potential windfarm sites to estimate the amount of electricity that may be generated.

The optimal operation of the newest generation of large wind turbines depends on having reliable measurements of the wind inflow characteristics.

Researchers at the Endowed Chair of Wind Energy (SWE) of the University of Stuttgart are working together with researchers from the University of Oldenburg and other partners on a new remote sensing technique, LIDAR (Light Detection and Ranging). They claim this laser-based measurement technique performs wind field measurements in a more flexible and economical way than measuring wind speed with anemometers mounted on masts. Having a remote sensing technique is particularly important in siting offshore wind farms.

LIDAR systems detect wind speed and direction based on the time delay of the laser beam reflected by airborne aerosols. The technology has been in use for decades for atmospheric research. Now the researchers aim to further develop LIDAR technology to establish it as a quality standard for wind field measurements, with the spatial and temporal resolution needed by the wind energy industry.

The SWE involves a group of partners that is evaluating the use of an existing commercial LIDAR system Leosphere in wind farm projects.

The research center ForWind at the University of Oldenburg is working on new methods for unsteady power curve estimation, while the German Aerospace Centre will apply its experience using LIDARs for atmospheric research.

Power curve measurements are performed on an onshore five megawatt prototype wind turbine belonging to Multibrid GmbH in Bremerhaven. In addition, the German Wind Energy Institute (DEWI) is providing its experience on standardised power curve measurements and supporting offshore measurements conducted at the research platform FINO1 in the North Sea (www.fino-offshore.de).

Finally, the Federation of German Wind Power (FGW) supports the creation of standards to be used by the wind energy industry.

The final results of this project, which is funded by the German Federal Environment Ministry, will be made available to the entire wind energy community. The research will also support development of the German offshore test site, Alpha Ventus. The wind farm, located 45 kilometres north of the island of Borkum, is planned to begin operation in autumn 2008.