The installation work was started at the end of July last year and about 65 of the total wind turbines are delivering electricity to the grid at on Germany’s mainland, some 110km away.

Project developers Vattenfall and Stadtwerke Munchen said the construction phase for the turbines has been completed three months ahead of schedule.

Full commissioning of the wind farm is expected to done in the coming few months. Once completed, the wind farm is expected to have an annual power production at 1.4 terrawatt hours.

For the wind project whose total cost is estimated to be €1.2bn, 72 of Siemens’ SWT-4.0-130 wind turbines with a nominal capacity of 4MW, hub height of 94.75m and with rotor diameter of 130m have been used.

The offshore wind turbines are supported by grounded monopile structures that have been installed at depths ranging between 26 and 33m.

The wind farm is expected to supply power to at least 200,000 German households and offset more than 400,000 tonnes of CO2 and more than 9000 tonnes of SO2 from entering the atmosphere.

Sandbank project director Niels Bjaert said: “It’s foremost the result of very good planning, selection of a good installation set up, contractual negotiations and monitoring, following up, mitigating risks and hard work.

“The latter comes as a result from a motivated, dedicated and focused team and a good cooperation with contractors, certifiers and authorities.”

Vattenfall project technical head Martin Zappe said: “The technology deployed on the project as well as the co-operation between all involved parties have gained a lot in terms of maturity.

“We will use these experiences for future projects to implement them as cost efficient as possible, also with regards to the new auction system for coming offshore projects in Germany.”

Image: MPI’ vessel installing the wind turbines at the Sandbank wind farm located in the German North Sea. Photo: Courtesy of Vattenfall.