Siemens has installed the HelWin1 offshore platform in the North Sea. HelWin1 will link the two offshore wind farms Nordsee Ost and Meerwind to the mainland. Using the Siemens technology installed on the platform, the alternating current power generated by the wind turbines is transformed into low-loss direct current for transmission onto land. Starting next year, this will enable the network operator and purchaser TenneT to supply clean electricity to more than 500,000 German households on the mainland. The land-based station, also supplied by Siemens to TenneT, is located northwest of Hamburg in Büttel, where electricity will be converted back into the alternating current power required for feeding into the grid.
The network operator TenneT contracted the consortium consisting of Siemens and the Italian cable specialist Prysmian for the HelWin1 offshore grid connection in 2010. This consortium is implementing a total of four North Sea grid connection projects for TenneT; HelWin1 and HelWin2 off of Helgoland, BorWin2 off of Borkum and SylWin1 off of Sylt.
The platform is equipped with a helipad and was fabricated by Nordic Yards at the shipyard in Wismar under contract by Siemens. Nordic Yards has been contracted by Siemens with the fabrication of two more HVDC platforms for the grid connections BorWin2 and SylWin. At 12,000 tons, the HelWin1 platform weighs more than 20 loaded and fully tanked Airbus A380 super airliners. The surface area of the platform, at 75 by 50 meters, is more than half the size of a soccer field. The platform’s seven decks, spanning a total height of 27 meters, accommodate 16 cabins for crewmembers with a total of 24 berths, a galley, sanitary facilities, a multi-purpose room equipped with sports equipment and a day room with satellite TV, in addition to housing all the technology and equipment required for HVDC transmission.