50Hertz Awards Marine Survey Contract for Ostwind 4, the First 525 kV HVDC Offshore Grid System in the German Baltic Sea

German transmission system operator 50Hertz has awarded critical marine warranty survey and engineering inspection contracts for Ostwind 4, an offshore grid ...

50Hertz Awards Marine Survey Contract for Ostwind 4, the First 525 kV HVDC Offshore Grid System in the German Baltic Sea

German transmission system operator 50Hertz has awarded critical marine warranty survey and engineering inspection contracts for Ostwind 4, an offshore grid connection project deploying 525 kV direct current technology in the Baltic Sea to evacuate 2 GW of wind capacity.

Pioneering 525 kV DC Technology in the Baltic Basin

While previous Baltic offshore connections operated on 220 kV three-phase AC systems, the increasing distance of newly tendered wind clusters from the German coastline requires a transition to High-Voltage Direct Current.

Ostwind 4 will gather 2,000 MW of power from deep-water wind concessions at a centralized 525 kV offshore converter platform, stepping up generated power and transmitting it ashore via low-loss extruded DC subsea cables.

Onshore Converter Station and Network Integration

On the mainland, 50Hertz will construct a modular multilevel converter (MMC) station in Mecklenburg-Vorpommern, feeding into the eastern German 380 kV transmission backbone.

The awarded marine contracts cover sea-bottom geotechnical verifications and heavy-lift installation surveys for the 25,000-tonne converter platform jacket scheduled for deployment in 2028.