Dutch transmission system operator TenneT has commissioned DolWin6, a 900MW high-voltage direct current (HVDC) connection, 90km offshore in the German North Sea.
DolWin6 was officially handed over to TenneT by Siemens Energy after several weeks of trial operations.
With the HVDC connection, the system operator now has the capacity to transmit 8GW of power from the German North Sea. Along with 3.5GW in the Dutch North Sea, the company’s total offshore capacity is now more than 11.5GW.
Construction on the DolWin6 project started in 2017 and it has a transmission capacity of 900MW.
On the associated offshore platform, the three-phase current generated by the offshore wind farms will be converted into direct current, which will be transported to the mainland in Hilgenriedersiel (East Frisia) via a 45km sea cable.
Another converter station and a transformer station at Emden/East will transform the direct current back into a three-phase current to be fed into the high-voltage electricity grid.
TenneT chief operating officer Tim Meyerjürgens stated: “Wind energy generated far out at sea is the essential building block for the energy supply of the future. The North Sea countries of Germany, the Netherlands, Denmark and Belgium set ambitious targets in Esbjerg last year and agreed to expand offshore to 65GW by 2030.
“With 40GW, TenneT alone will transport almost two-thirds of this energy onshore. And the good news is: we are making great strides forward! With 11.5GW, we are already more than a quarter of the way there.”
The topside of the converter station weighs 11,000 tonnes (t) and was placed on a 5,000t foundation structure. The total height of the two structures is 82m and the platform itself will rise 53m above the surface of the sea.
