Jasmund Substation Nears Baltic Sea Installation After Topside and Jacket Load-Out
November 18, 2025
The Jasmund offshore substation project for German grid operator 50Hertz, being delivered by HIS consortium, has reached a key milestone with the load-out of both its topside and jacket, marking a major step toward offshore installation in the Baltic Sea.
The topside, built at HSM Offshore Energy’s Stormpolder yard in the Netherlands, measures 48 meters by 33 meters, stands 17.5 meters high and weighs about 4,500 tonnes. The matching 4,500-tonne jacket, rising 72 meters, was manufactured at the Smulders yard in Vlissingen.
Both structures were transferred onto barges following detailed planning to ensure safe load distribution, structural stability and transport readiness. A customized grillage system was designed to support the substation during the transfer.
The project is being executed by the HSI consortium – HSM Offshore Energy, Smulders and Iv – which holds the full EPCIC scope covering engineering, procurement, construction, installation and commissioning. OSS Jasmund is the first of three offshore substations the consortium is delivering for 50Hertz.
Once operational, the Jasmund substation will have a capacity of 300 MW, supplying renewable electricity to around 260,000 households. It will serve as the grid connection point for the Windanker offshore wind farm, located northeast of Germany’s island of Rügen.
Earlier this year, the HSI joint venture completed the rollout of the topside and lifted transformers at the Stormpolder yard, marking the first substation platform and jacket to be delivered under the partnership.
