Fredericia (Denmark) / Berlin (Germany) - In a landmark development for Europe’s clean energy transition, Siemens Energy Global GmbH & Co. KG, together with Siemens Energy A/S, has been awarded a €2.31 billion contract for the supply and construction of high-voltage direct current (HVDC) converter substations as part of the Bornholm Energy Island (BEI) project.
The award, announced in the Official Journal of the European Union (OJ S 180/2025) under Contract Notice No. 614463-2025, was issued jointly by Danish grid operator Energinet Eltransmission A/S and German transmission system operator 50Hertz Transmission GmbH.
Driving Europe’s offshore power integration
The Bornholm Energy Island project is a cornerstone of Denmark and Germany’s efforts to integrate offshore wind power and strengthen cross-border electricity transmission in Northern Europe. Under the agreement, Siemens Energy will deliver and commission three major converter facilities - HVDC/HVAC Substation Zealand, HVDC/HVAC Substation Bornholm, and HVDC Substation Stilow - alongside a Master Controller System that will manage and optimise power flows between the two national grids.
The scope also includes several Service Level Agreements (SLAs) to ensure long-term maintenance and reliability. One SLA will cover the commissioning period, followed by two separate post-commissioning agreements - one managed by Energinet in Denmark and the other by 50Hertz in Germany - aligning with each operator’s maintenance obligations.
Strategic and financial context
Valued at €2,312,253,400, the contract is among Europe’s most significant power transmission infrastructure awards to date. It is partially financed by European Union funds and falls within the framework of the Government Procurement Agreement (GPA).
The project will serve as the electrical backbone of the Bornholm Energy Island, a central hub for offshore wind integration capable of connecting several gigawatts of renewable capacity to the continental grid. It aims to enhance grid resilience, optimise renewable power distribution, and enable future energy sharing across European borders.
The award follows a previous competitive dialogue procedure under reference SQS 344674, which did not yield suitable bids. As a result, the buyers proceeded with a negotiated procedure without prior call for competition, in line with Article 50a of the EU Utilities Directive (Directive 2014/25/EU). The selection of Siemens Energy was based on its proven technological expertise in HVDC systems and its successful track record on interconnectors such as Viking Link and Cobra Cable.
The contract is contingent upon Denmark’s Final Investment Decision (FID) on the Bornholm Energy Island project, currently under governmental review. Once approved, Siemens Energy will proceed with design, manufacturing, installation, and long-term service support from its facilities in Erlangen (Germany) and Ballerup (Denmark).
Powering the green transition
The Bornholm Energy Island represents a bold step toward achieving Europe’s climate and energy objectives under the European Green Deal and Fit for 55 initiatives. By linking Denmark and Germany through advanced HVDC infrastructure, the project will enable efficient, high-capacity renewable energy transmission while strengthening the regional electricity market’s flexibility and security.
With Siemens Energy at the helm, supported by Energinet and 50Hertz, the Bornholm Energy Island is poised to become a benchmark for future offshore energy hubs, marking a decisive move toward a fully interconnected, carbon-neutral European power system.
