50Hertz and Energinet have joined forces to fully harvest the offshore wind potential held in the Baltic Sea, power the green transition in Germany and Denmark, and spearhead a new idea for connecting offshore wind farms across borders: the Bornholm Energy Island (BEI) project. This innovative and visionary project will connect multiple wind farms together via a single hub and transport the green electricity that they generate to consumers in both countries while providing transmission capacity for cross-border trading.
The green future of offshore wind hubs and hybrid connections
BORNHOLM ENERGY ISLAND
VISION & TECHNICAL FEATURES
Together, 50Hertz and Energinet want to establish a power hub on the island of Bornholm that is able to provide electricity to consumers in either country, depending on the market and demand in Germany, Denmark and Europe more widely. Electricity generated by the wind farms located off the coast of the island will be centralised at this hub and then converted into high-voltage direct current (HVDC) and transported via 525 kV HVDC sea and land cable systems to onshore substations in Zealand (in Denmark) and Mecklenburg-Western Pomerania (in Germany). In addition, the BEI project will enable the local community on the island to be connected to both Zealand and continental Europe.
Cooperation between countries is the way forward
50Hertz and Energinet are pioneering innovators. BEI will pave the way to a future in which offshore wind energy is no longer harvested by individual countries alone. Instead, in line with the offshore wind potential held by different countries and electricity demand in these, two or more countries will cooperate to efficiently integrate the green electricity generated by offshore wind farms into their energy systems.
We at 50Hertz and Energinet hold a significant amount of expertise in feeding electricity from offshore wind farms into our power grids. The Kriegers Flak - Combined Grid Solution (KF CGS), our joint project which has been fully operational since 2021, laid the foundations for making hybrid interconnectors a reality in both the Baltic Sea and the North Sea. We will continue to use our know-how to implement ever-evolving, more complex and more efficient on- and offshore energy hubs.
NEWS & EVENTS
Denmark: Public consultation begins
On Danish soil, the public consultation phase for the planned high-voltage cable connection between the Bornholm Energy Island and Germany has now begun. In Germany there have been public consultation formats earlier in 2025.
The consultation for the part located in Denmark – also known as the idea phase – is part of the environmental assessment process and is carried out by the Danish Agency for Green Land Use and Aquatic Environment (SGAV), which is the responsible environmental authority.
During this phase, citizens, organisations and authorities are invited to share knowledge, ideas and suggestions on which environmental and social aspects should be examined in the forthcoming environmental studies.
The environmental assessment covers the part of the project located within Denmark – from the land cable connecting the converter station on Bornholm to the subsea cable up to the Danish–German maritime border.
As the consultation relates to this part of the project and follows Danish environmental procedures, the process – including an online public meeting on 26 November – will be conducted in Danish. For the Bornholm Energy Island (BEI) project, the information event is part of the mandatory public consultation process prior to submitting the permit application for a 'Project of Common Interest' (PCI).
The section of the project located in German waters – from the maritime border to the landfall and converter station in Rappenhagen – will be subject to environmental assessment and permitting by the relevant German authorities.
Energinet and 50Hertz, the transmission system operators jointly developing the interconnector project, will support the consultation process by presenting technical information and answering questions during the online meeting.
The interconnector is part of the broader Bornholm Energy Island project, which will collect and transmit renewable power from future offshore wind farms in the Baltic Sea to both Denmark and Germany.
Further information about the consultation phase, the environmental assessment and the project – including details about the online public meeting – is available in Danish on Energinets website: www.energinet.dk/bornholminterconnector
Energinet is an independent public enterprise owned by the Danish Ministry of Climate, Energy and Utilities. Energinet owns, operates and develops the transmission systems for electricity and gas in Denmark. Energinet’s purpose is to own, operate and develop the overall energy infrastructure and manage related tasks, thus contributing to the development of a climate-neutral energy supply.
50Hertz operates the electricity transmission system in the north and east of Germany, which it expands as needed for the energy transition. Within these regions, 50Hertz and its around 2,100 employees ensure that 18 million people are supplied with electricity around the clock. 50Hertz is a forerunner in the field of secure integration of renewable energy. In our grid area, we want to integrate 100 percent renewable energies securely into the grid and system by 2032 - calculated over the year. The shareholders of 50Hertz are the Belgian holding Elia Group (80 percent), which is listed on the stock exchange, and the KfW bank group with 20 percent.