
Roll Out Zingst Offshore Substation (OSS) Topside for 50Hertz
The HSI Joint Venture, comprising HSM Offshore Energy, Smulders, and Iv, has successfully and safely rolled out the topside of OSS Zingst at HSM Offshore Energy’s yard in Schiedam. This milestone marks the next step in delivering Germany’s newest and most powerful offshore wind infrastructure for transmission system operator 50Hertz. OSS Zingst is one of two offshore substations, together with OSS Darß, forming the OST-6-1 grid connection in the German Baltic Sea. With a combined transmission capacity of 927 MW, OST-6-1 will connect the Gennaker Offshore Wind Farm, which will be Germany’s largest upon completion, to the onshore grid.
A Significant Engineering Achievement
The topside of OSS Zingst is an impressive structure, measuring 48 × 33 × 17.5 metres (L×W×H) and weighing 4,700 metric tonnes. Once installed offshore, the offshore substation will collect and transform the 450 MW of power generated by the Gennaker wind farm before transmitting it to the onshore grid. The roll-out at the Schiedam yard marks a key milestone in the project and demonstrates the seamless collaboration within the HSI-consortium and the way the engineering has progressed into a buildable platform as the project works toward the upcoming load-out, sail-away, and offshore installation.
Collaborative Expertise Through the HSI-Consortium
Under the EPCIC contract, the HSI-consortium is responsible for the engineering, procurement, construction, installation, and commissioning of the Ostwind3, Zingst and Darß topsides and their jackets. The joint ventures integrated approach enables efficient coordination, consistent technical consistency, and the highest safety and quality standards, which are essential for delivering a project of this scale.




