Siemens has completed installation of the offshore platform for the direct-current connection HelWin2, working under contract from the German-Dutch grid operator TenneT.
Last month, the heavy-lifter Thialf hoisted the HelWin2 platform topsides from its transport barge on to the previously installed jacket.
The HelWin2 platform was both constructed and installed by Heerema. The marine and land-based cabling were supplied and laid by the cable specialist Prysmian Group.
The HelWin2 grid connection will transmit offshore-generated wind power to land for some 700,000 German households. The first offshore windfarm that will be connected is to be Amrumbank West.
The installation marks “one more major interim milestone” in terms of achieving the German government’s offshore expansion goals.
The newly installed HelWin2 platform lies 35km north of the island after which it was named, Heligoland, directly adjacent to the HelWin1 platform that Siemens installed a year ago.
Earlier this year in April, Siemens installed the BorWin2 platform off the coast of Borkum.
All told, Siemens has built five North Sea grid connections for TenneT. The first four are due to be commissioned over the next 12 months or so and provide a combined transmission capacity of over 2.9 gigawatts.
The fifth connection, which was ordered earlier this year, BorWin3, is to be ready for operation in 2019.
Each of the transformer platforms comprising the German offshore transmission network being built and installed by Siemens is equipped to convert the AC output of turbines to DC for export.
The power output is reconverted to AC at its landfall and fed into the German grid.
The use of low-loss high-voltage direct current (HVDC) technology means that transmission losses will be less than 4%.
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