Siemens Wins €1Bn Bornholm Energy Island HVDC Contract
Siemens Energy has secured a contract for the converter station infrastructure at the Bornholm Energy Island project, marking a major development in Europe's offshore wind expansion. The agreement, valued at over €1 billion, tasks Siemens with the design, production, transport, installation, and commissioning of four converter stations—two located on Bornholm, one on Denmark’s Zealand, and one in Germany. These stations will serve as the backbone of what is set to be the world’s first hybrid high-voltage direct current (HVDC) interconnector, delivering an initial three gigawatts of offshore wind power from the Baltic Sea to onshore grids in both Denmark and Germany by the mid-2030s.
Bornholm Energy Island has a total budget approaching €7 billion and aims to become a central hub for sea-based wind power in Northern Europe. The electricity generated by the offshore turbines will be centralized on Bornholm, then converted by Siemens’ HVDC technology for efficient long-distance transmission. The interconnectors, composed of advanced 525 kV HVDC cable systems supplied by NKT, will span approximately 200 kilometers offshore and nearly 17 kilometers onshore, linking Bornholm with Zealand and Germany’s Mecklenburg-Western Pomerania. NKT, which previously won the German connection contract, will manufacture the cables at their Karlskrona facility in Sweden, with offshore installation scheduled via their new vessel, NKT Eleonora.
This innovative project is being led by Danish and German transmission system operators Energinet and 50Hertz, both of whom emphasize its role in transforming cross-border energy reliability and grid flexibility. The strategic importance of Bornholm Energy Island is underscored by the European Union’s €645 million subsidy through the Connecting Europe Facility (CEF) for Energy, designed to reduce Denmark’s financial burden and foster further offshore wind integration across borders. Despite initial cost-sharing disputes—especially as most generated energy will supply Germany—the EU’s funding has enabled progress, accompanied by state-backed guarantees from Germany.
Bornholm Energy Island is designed not merely as a conventional transmission project, but as a model for future offshore hubs integrating multi-country wind assets. Its hybrid nature draws directly on operational experience from projects like Kriegers Flak, promising technical and commercial innovation that will anchor Europe’s green energy ambitions. Siemens’ involvement in both Danish and German converter installations consolidates its position as a leading HVDC technology supplier amid a rapidly growing portfolio of European sea-based wind interconnectors, reinforcing Bornholm’s status as a landmark in the continent’s energy transition.
