E.ON and Statoil gave the green light to the construction of the 385 MW Arkona Becken Südost wind farm, 35 km northeast of the island of Rügen.

The use of seismic surface surveys made it possible to stick to schedule on the EUR 1.2 billion project despite changes to the wind farm design - 60 turbines instead of 80 because of the switch to the larger 6 MW class, without the need for further post-surveys, Fraunhofer said.

Seismic surveys were conducted using Fraunhofer IWES’ multi-channel seismic system which enabled the company to look at deeper layers, as the support structure of a wind turbine penetrates 50 meters into the seabed.

By the time the decision to install the larger class of turbine was taken, the results of 100 drilling operations and 13 pressure sounding tests for the wind farm were already in. Then, to ensure optimal operating conditions, the layout of the turbines was adapted. This meant that some of the drilling and sounding locations no longer coincided with the new turbine locations. Most of the existing exploration profiles could not be directly applied to the new locations.

With the assistance of a geotechnical company, the properties of the existing drilling profiles were applied to the new turbine locations for which the seismic survey had been conducted, Fraunhofer explained.