Sandbank offshore wind farm supplies first power

The offshore wind power plant Sandbank, located 90 kilometers west of the island of Sylt, has now supplied the German electricity network with its first wind power from the North Sea. The first of a total of 72 wind turbines are successively in the commissioning phase for the production of electricity. Sandbank is expected to be fully connected to the grid, and to be delivering at full capacity by early spring-time 2017.

“We are very pleased The erection of wind turbines for Sandbank has started in late July and during the last weeks 21 wind turbines were successfully erected. Fully commissioned and in continuous operation the park will generate an annual amount of electricity which corresponds to the consumption of 400,000 German households. Compared to electricity produced from conventional sources, Sandbank avoids more than 700,000 tons of CO2emissions annually.

During the commissioning phase of the wind turbines the service operations vessel “Acergy Viking” is deployed by the project. By using this modified type of ship, the project expects a significant three months gain of time compared to the original planning. This “walk-to-work” vessel features a special gangway system which enables the commissioning teams to climb onto the wind turbines directly. The new concept also enables for work with enhanced safety standards and to be carried out 24 hours per day. This concept is used in the North Sea around Germany for the first time with the commissioning of the Sandbank wind turbines.

“The erection of the wind turbines for Sandbank is running so smoothly and that we have already 21 turbines up”, says Hergen Stolle, responsible package manager for wind turbines at Vattenfall. The commissioning of the first wind turbines underlines the fact that it is possible to start with the generation of electricity shortly after the erection phase. It proves that offshore technology is becoming more and mature. And it also shows that the co-operation between all project partners works very well.”

Christian Moldan, Head of Offshore Wind Projects at SWM, reassures: “The according-to-plan- running erection phase of our project Sandbank is a good proof point for the fact, that the offshore business makes now profitable use of the experiences already made in previous projects. This includes Vattenfall and Stadtwerke München. We were able to transfer the know-how from the “sister project” DaTysk to Sandbank and thus to carry on with our successful co-operation.”

When the wind farm is in full operation, an offshore substation will collect the wind energy of all 72 turbines, transform it from an AC voltage of 33 kilovolts (kV) to 155 kV, and deliver it to a converter station, from where the energy will be transported as DC over a distance of 165 kilometres to the landing point in Büsum, Schleswig-Holstein.

The Sandbank project

The investment costs for the Sandbank offshore wind farm are around EUR 1.2 billion. Vattenfall holds a 51% stake in Sandbank Offshore GmbH, which was set up to implement the project, while SWM holds a 49% stake. A total of 72 Siemens wind-based power plants in the 4-megawatt (MW) class will be erected, providing a total installed capacity of 288 MW. Sandbank is scheduled to go into full operation in 2017. This will provide a combined portfolio of 576 MW of installed generation capacity, making Vattenfall and SWM two of the largest operators of offshore wind farms in Germany.