DanTysk Offshore Wind Farm, Germany

DanTysk offshore wind farm is a 288MW power project to be located in the North Sea, at about 70km west of the island of Sylt in northern Germany. It is a collaborative implementation by Vattenfall and Stadtwerke München (SWM) through a joint venture called DanTysk Offshore Wind GmbH.

With 51% stake, Vattenfall will build and maintain the offshore wind farm facilities. The remaining 49% stake will be held by SWM. The project is estimated to cost more than €1bn.

The green electricity produced by the wind farm will be sufficient to power 500,000 houses at an average consumption rate of 2,500kWh per home.
The project will be completed in early 2014.

Development

In 2007, Vattenfall acquired the DanTysk project from the previous developer Geo Gesellschaft für Energie und Ökologie. In July 2010, Stadtwerke München formed a joint venture with Vattenfall by purchasing 49% stake in the project.

Vattenfall undertook the project to achieve its long-term goal of generating electricity from offshore wind farms. SWM undertook the project with the aim of powering 800,000 households in Munich with renewable energy.

Plant details

The DanTysk offshore wind farm will span in about 71km² of surface area in the sea. It will have 80 turbines with rotor diameter of 120m and capacity of 3.6MW each. The turbines will be built at depths ranging between 21m and 31m.

Turnkey process

Siemens Energy will supply its SWT-3.6-120 model wind turbines for the project under a contract awarded in October 2010. It will also be responsible for installing, commissioning and maintaining the turbine units.

In December 2010, a turnkey contract was awarded to a joint venture of Strukton Systems and Hollandia for supplying the 155kV/33kV offshore transformer substation for the wind farm. The consortium was selected through a European-wide competitive tendering process. Seaway Heavy Lifting is a subcontractor to the consortium.

The jacket / topside substation will have three decks, a tank station and a helicopter landing pad. It will be installed in 2012 and commissioned in 2013.

In February 2011 DanTysk Offshore Wind signed an agreement with the Danish shipping company Swire Blue Ocean (SBO) to use its heavy lift vessel for transporting and installing the wind turbines at the project site from Esbjerg seaport, Denmark.

The 161.9m-long vessel will have a 1,200t capacity, twin-hook crane and a helipad. The ship, called Pacific Orca, is being built at Samsung Heavy Industries' shipyard in South Korea.

It will be ready in 2012 and the wind turbines transportation will begin in 2013. The environmental standard requirements of the Pacific Orca will be certified by GL-Group Germanischer Lloyd.

Grid network

The power produced at the wind farm will be transmitted to a new onshore substation being built in Büttel, Schleswig-Holstein by the German-Dutch distribution grid operator TenneT.

TenneT operates an offshore platform called SylWin alpha in the North Sea. The platform will be connected to the onshore electricity grid network by a 160km sea cable and a 45km land cable to the new substation in Büttel, Schleswig-Holstein.

Distribution

The AC power generated by the 80 wind turbines at the DanTysk offshore wind farm will be collected by the offshore transformer substation. It will be connected to the high-voltage direct current (HVDC) converter station SylWin alpha.

The AC will be converted to HVDC and then transmitted to the onshore Büttel station via the cable network. This will avoid transmission losses. The onshore converter station will convert the DC back into AC. The electricity will then be distributed through the national ultra-high voltage electricity grid.

Construction

Construction of the DanTysk offshore wind farm is scheduled to start in 2012. The turbines are scheduled to be installed in 2012 and the wind farm is expected to be commissioned in 2013.

The project has received necessary permits from the relevant authorities and the preconstruction works have started. As of February 2011, the array cabling and foundations were in progress.