Siemens has completed installation of the offshore platform for the direct-current connection HelWin2. Working under contract from the German-Dutch grid operator TenneT, Siemens has thus achieved a decisive milestone of the German grid connection projects. “We have now installed three high-tech platforms for TenneT in the North Sea. The HelWin2 project is now in the homestretch to begin operation in the coming year," says Jan Mrosik, CEO of the Power Transmission and Smart Grid Divisions of Siemens AG. “We have achieved one more major interim milestone, and are step by step accomplishing the German government’s offshore expansion goals”, says Lex Hartman, member of TenneT's executive board.
The newly installed HelWin2 platform lies 35 km north of the island after which it was named, Heligoland, directly adjacent to the HelWin1 platform Siemens successfully erected earlier in August 2013. Earlier this year in April Siemens already erected the BorWin2 platform off the coast of Borkum. All told, Siemens builds five North Sea grid connections for TenneT.
The first four are to begin commercial operation successively over the second half of 2014 and the first half of 2015, and in sum total provide transmission capacity of over 2.9 gigawatts. The fifth connection recently ordered this year, BorWin3, is to be ready for operation in 2019. Using the Siemens technology installed on the platforms, the alternating current power generated by the wind turbines is transformed into direct current for efficient transmission to the mainland. At the associated land-based stations, the electricity generated by the connected wind farms is converted back into the alternating current power required for feeding into the transmission grid. Thanks to Siemens' low-loss high-voltage direct current (HVDC) technology, transmission losses are less than four percent. The platforms are designed to operate for decades in the rough North Sea conditions, and are fully automated. The HelWin2 platform was constructed and installed by Heerema. The marine and land-based cabling were supplied and laid by the cable specialist Prysmian Group.