After successful testing, grid operator TenneT and Siemens have now initiated the trial run of the BorWin2 direct current link. After several weeks of trial operation, the grid link will be able to go into controlled operation in the first few months of 2015. With a transmission capacity of 800 MW, the BorWin2 grid link can supply about 800,000 households with clean electricity.
In addition to the HelWin1 facility already undergoing testing, Siemens is currently preparing two additional high-voltage direct current (HVDC) transmission links in the North Sea for commercial operation for TenneT. Siemens received an order for a fifth direct current link in the spring of 2014.
Siemens installed the BorWin2 HVDC platform, located about 100 kM northwest of the North Sea island of Borkum, during the summer. Prysmian, a consortium partner and cable expert, was responsible for the installation of two 200-km-long submarine cables. After successfully installing the platform, numerous commissioning tasks were necessary, at times requiring up to 100 employees to simultaneously work on the platform. After successfully connecting the Global Tech 1 wind farm, the BorWin2 link fed electricity into the grid for the first time in initial tests conducted in early September. Fifty percent of the grid connection’s capacity is planned for another wind farm. Since construction of the wind turbines has not yet begun, TenneT expects that the 800-MW link will be used at only 50 percent capacity for the next two years.
Siemens will utilize HVDC technology, installed both on the offshore platform as well as in the land-based converter station in Diele, East Frisia, to efficiently bring the wind-generated electricity to land. The wind-generated power will first be transported as alternating current to the BorWin2 converter platform, converted there into direct current, and brought to land via submarine cables. The land-based station converts the direct current back into alternating current and feeds it into the high-voltage grid. For lengths of 80 km or more, HVDC is the only efficient transmission solution with a maximum loss of only 4 percent including the cable.