Smulders has completed the load-out of the OSS Zingst and OSS Darß topsides for 50Hertz‘s OST-6-1 offshore grid connection in the German Baltic Sea. The Zingst topside was loaded out in Schiedam and the Darß topside in Vlissingen, following the load-out of the substations’ jackets at the same yards. Each offshore substation has a capacity of approximately 450 MW.

The two substations are part of OST-6-1, which will connect the Gennaker Offshore Wind Farm to the onshore 50Hertz transmission network. According to 50Hertz, the grid connection has a maximum transmission capacity of 927 MW and will use three 220 kV alternating-current submarine cable systems. The cable route will extend up to around 53 km through the Baltic Sea and around 35 km onshore to the Gnewitz substation in Mecklenburg-Western Pomerania.

The HSI Joint Venture, comprising Smulders HSM and Iv, is responsible for the EPCIC scope covering the topsides and jackets for OSS Zingst and OSS Darß. Construction of the Darß topside started in March 2024, with final assembly in Vlissingen. Work on the Zingst topside began in May 2024 at Schiedam. Smulders previously reported that the Zingst topside measures 48 m by 33 m by 17.5 m and weighs approximately 4,700 t.

Gennaker is being developed by Skyborn Renewables around 15 km north of the Fischland-Darß-Zingst peninsula. Skyborn Renewables lists the wind farm with a maximum generating capacity of 976.5 MW, separate from the 927 MW maximum grid connection capacity specified by 50Hertz for OST-6-1. The developer secured the project’s construction permit in December 2025.

With the jacket and topside load-outs complete, Smulders has identified the next stage as the sail-away of the offshore substation structures.