As part of the "GW Wakes" joint project, the Carl von Ossietzky University Oldenburg is carrying out research into wind currents in very large offshore wind farms with 100 or more turbines, in order to improve the calculability of wind power generation at sea. The German Federal Ministry for the Environment, Nature Conservation and Nuclear Safety is funding the project to the tune of around 3.8 million euros over three years.

Wind turbines operated on farms influence one another reciprocally in terms of energy yield and mechanical load. Increased turbulence in the wake does not spread like a shadow but rather in meandering form, similar to a billow of smoke (wake meandering). This wake causes burdens on the turbine and results in complex overlaying of the wakes of the wind-farm turbines. Whilst the usual wind-farm calculation models determine the efficiency of the farm with sufficient precision, there are thus far hardly any processes with which the wake of rotors and the resulting loads on the downstream wind turbines can be simulated.

GigaWatt wakes, abbreviated to GW wakes, are examined in the research project “Analysis of the shading losses and wake turbulence characteristics of large offshore wind farms through comparison of alpha ventus and BARD Offshore 1 (GW wakes)”. For the first time, this project should provide data on the shading losses in a representatively sized offshore wind farm. The funding of the German Federal Ministry for the Environment, Nature Conservation and Nuclear Safety also enables the use of a laser-optical remote sensing device that is unique throughout the world. It enables the measurement of wind current, swirls and shading on wind turbines. It is therefore possible to examine the effect of the wake current on wind farms in the surrounding area. “We are working with three physically spread laser devices which use synchronised light impulses to examine the currents and turbulence over a radius of up to eight kilometres,” is how Project Manager Prof. Dr. Martin Kühn explains the research opportunities. In a way similar to medical ultrasonic examination, moving colour images indicate the position at which critical swirls and turbulence occur in the wind farms. The project aims to further improve the economic efficiency of wind turbines and offshore wind farms as well as the ability to plan wind power production. The Oldenburg scientists are supported with extensive operating data and access to the BARD Offshore 1 offshore wind farm situated 100 kilometres to the north-west of Borkum.

Four parties are carrying out research as part of the joint project: The working groups of “Oldenburger Physik”, the members of the Centre for Wind Energy Research of the Universities of Oldenburg, Bremen and Hanover (ForWind), the Fraunhofer project group “Computational Fluid and System Dynamics” in Oldenburg and BARD Engineering GmbH belong to the project consortium.

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