The offshore converter platform SylWin alpha was undocked at the Nordic Yards shipyard in Warnemünde last week.
The 15,000 tonne yellow topside left the dock in the morning on the barge “Nordic Giant 101”: the platform – aligned diagonally across the dock – was built on the barge because SylWin, at 83 metres long and 56 metres wide, was too big for the dry dock.
The completed platform now lies at the quay edge at Nordic Yards in Warnemünde. Next, depending on the weather and installation preparations, the platform will be towed by sea-going tugs on a several-day journey to the installation site in the North Sea. Once on site, 70 kilometres west of Sylt, the platform will be installed 23 metres above the water’s surface. The substructure has already been anchored to the seabed at the end of April.
SylWin alpha is part of the grid connection SylWin1 and serves the eastern North Sea offshore wind farms DanTysk, Sandbank and Butendiek. The 25 metre high, seven-deck topside contains the electrical infrastructure for high-voltage direct current (HVDC) electric power transmission: this is where the alternating current generated by the offshore wind turbines is converted into direct current for more efficient transmission to the mainland.
The platform, with its 864 megawatts transmission capacity, will supply around 900,000 German households with offshore wind electricity from 2015. Once commissioned, the fully automated facility will be monitored and controlled from onshore and is designed to operate for decades in the harsh conditions of the North Sea.
SylWin alpha is the third platform to be built by Nordic Yards for Siemens Energy and grid operator TenneT. HelWin alpha and BorWin beta were installed in the North Sea in August 2013 and April 2014 respectively. The construction of DolWin gamma, the fourth and largest offshore platform in Nordic’s order book, is due to start this year.