The HSI joint venture, comprising HSM Offshore Energy, Smulders and Iv, has completed the installation of the Jasmund offshore substation (OSS) at the Ostwind 3 location in the Baltic Sea, marking a key milestone in Germany’s offshore grid expansion program.
The installation included a 72-metre-high jacket and more than 4,000 tonnes of offshore structures and was carried out for German transmission system operator 50Hertz. With the main structures now in place offshore, the project will move into the testing and commissioning phase.
Once operational, the Jasmund OSS will have an installed capacity of 300 MW. It will connect the Windanker offshore wind farm to the onshore grid, and enable the supply of electricity to around 260,000 households.
The facility forms part of 50Hertz’s offshore grid infrastructure designed to connect offshore wind generation in the German Baltic Sea to the onshore transmission network.
The project is being delivered by the HSI joint venture under a full EPCIC scope, covering engineering, procurement, construction, installation and commissioning of both the topside and supporting jacket. The milestone follows the completion of fabrication, transport and offshore installation activities coordinated between the project partners.
The offshore installation followed the sail-away of the topside from HSM Offshore Energy’s Stormpolder yard in Rotterdam, where the structure passed beneath several city bridges during transport. The jacket, built at Smulders’ yard in Vlissingen, was transported separately to the Baltic Sea. Installation was carried out northeast of the island of Rügen.
Jasmund is the first of three offshore substations being delivered by the HSI joint venture for 50Hertz. The OSS Zingst and OSS Darß substations will follow as part of the OST-6-1 grid connection, linking the Gennaker East and Gennaker West offshore wind farms to the onshore grid.
Together, the three substations will provide a combined capacity of around 1.2 GW and are expected to supply electricity to more than one million households once completed.