By January 2026, 50Hertz had completed laying the Ostwind 3 export cables at sea between the Jasmund offshore platform northeast of Rügen and the new Stilow grid connection point, along with the approximately four‑kilometre section on land, marking the completion of the offshore cable installation for the grid connection.
In a January 2026 update on the Ostwind 3 grid connection project, 50Hertz reported that installation of the approximately four‑kilometre onshore cable route between the Vierow landing point and the new Stilow substation in the Vorpommern‑Greifswald district has been completed, finalising the land section of the export cable system.
As part of 50Hertz’s Ostwind 3 grid connection project, the Jasmund offshore platform topside, equipped with transformers, switchgear and other electrical and communication components, was lifted from a 200-metre-long floating work vessel onto its pre-installed steel jacket substructure with millimetre precision at 4 a.m. on 17 December 2025, completing installation of the offshore substation 40 kilometres northeast of the island of Rügen.
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Ostwind 3 is a German Baltic Sea HVAC offshore grid connection developed and operated by transmission system operator 50Hertz Transmission GmbH to integrate the Windanker wind farm area (O‑1.3) in the Westlich Adlergrund site into the German transmission grid. The connection comprises a single 22...
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OST-1-4
As part of the Ostwind 3 grid connection project, the steel substructure (jacket) for the Jasmund offshore platform, manufactured at a shipyard in Vlissingen in the Netherlands, was shipped to the Baltic Sea at the beginning of December 2025 and then deeply anchored in the seabed using steel piles off the island of Rügen.
Cable installation execution phase began Q2 2025. Asso.subsea installing 100+ km submarine export cable (220 kV). Axess Technologies handling nearshore cable pull-in and jointing.
On 7 January 2025, Axess Technologies was awarded a contract by Hellenic Cables for Ostwind 3 to plan and pull internal 66 kV and 220 kV platform cables into the project’s offshore high-voltage substation, with engineering already underway and execution scheduled to start in the second quarter of 2025 at HSM’s Stormpolder yard in the Netherlands.
50Hertz commenced onshore substation construction for Ostwind 3 grid connection. Archaeological surveys from April 2024, main construction from summer 2024.
BNetzA confirmed Ostwind 3 in Netzentwicklungsplan (NEP) 2037/2045 (2023) on 1 March 2024. This confirmation under §12c EnWG creates the legal basis for the responsible TSO to plan, procure, and construct the offshore grid connection system.
BNetzA confirmed the Netzentwicklungsplan Strom 2037/2045 (2023 edition) on 1 March 2024 under section 12c of the German Energy Industry Act (EnWG). This confirmation creates the legal basis and obligation for the responsible TSO to plan, procure, and construct this offshore grid connection system. For regulated German TSO offshore grid connections, the BNetzA NEP confirmation functions as the de facto Final Investment Decision: unlike merchant or developer-led projects that require a separate board-level investment decision and financial close, the NEP confirmation simultaneously authorises and obligates the TSO to invest. Costs are recovered through the offshore grid levy (Offshore-Netzumlage). The NEP 2037/2045 (2023) schedules 25,980 MW of offshore transmission capacity across 16 grid connection systems for commissioning between 2026 and 2032.
On 22 December 2023, the German Federal Maritime and Hydrographic Agency (BSH) issued the planning approval decision (Planfeststellungsbeschluss) for the Ostwind 3 offshore grid connection, comprising the export cable OST-1-4 and the Jasmund transformer platform for the site O-1.3 in the German Exclusive Economic Zone of the Baltic Sea. The approval was granted under Section 45 of the Offshore Wind Energy Act (Windenergie-auf-See-Gesetz) in the version applicable until 31 December 2022, in connection with Section 74 of the German Administrative Procedure Act. This is the primary project-specific planning consent authorising construction and operation of the offshore grid connection infrastructure, separate from the strategic BNetzA NEP 2037/2045 confirmation of March 2024 that establishes the legal basis for TSO investment under §12c EnWG. BSH formally announced the decision on 19 January 2024 and published the decision documents from 22 January to 5 February 2024.
Following its 12 May 2023 announcement of receipt of the Ostwind 3 planning approval application, the German Federal Maritime and Hydrographic Agency (BSH) opened the public consultation window for the Ostwind 3 planning documents on 15 May 2023. Under the Offshore Wind Energy Act (Windenergie-auf-See-Gesetz) planning approval procedure, the documents were made available for public inspection and written objections. This formal participation phase is a required step before BSH can issue the Planfeststellungsbeschluss, which was ultimately granted on 22 December 2023 covering the OST-1-4 export cable and the Jasmund transformer platform.
On 12 May 2023, the German authority BSH announced that it had received an application from 50Hertz Transmission GmbH to initiate the planning approval procedure under the Offshore Wind Energy Act for the construction and operation of the Ostwind 3 grid connection system OST-1-4 and its offshore transformer platform in the German Exclusive Economic Zone of the Baltic Sea. As part of this process, BSH published the associated plan documents online on its website for public access.
On 11 January 2023, Asso.subsea announced it had been awarded by Hellenic Cables the transportation, installation, and protection contract for the single 220 kV export submarine cable system on Ostwind 3, covering more than 100 km of route with shallow waters, HDD landfall pull-in, boulder fields, crossings, and varied seabed conditions, using its specialist cable-laying and trenching vessel fleet.
In October 2022, 50Hertz awarded Hellenic Cables a turnkey contract to design, supply, store, install, joint, terminate, test, and commission the Ostwind 3 export cable system, comprising 105 km of 220 kV subsea three-core export cable, 13.5 km of 220 kV onshore export cable, and 2 km each of 220 kV and 66 kV platform cables to connect the Windanker offshore wind area to the German extra‑high voltage grid.
By October 2022, the offshore high-voltage substation for the Ostwind 3 grid connection had been awarded to a Dutch-Belgian joint venture of HSM Offshore Energy, Smulders, and Iv-Offshore & Energy, which will deliver the HVAC offshore platform that collects power from the Windanker area and transmits it towards the German grid.
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