The green future of offshore wind hubs and hybrid connections



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.


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.


The German Minister for Economic Affairs and Climate Action, Robert Habeck, and Danish Minister for Climate, Energy and Utilities, Lars Aagaard (right). Photo: Federal Ministry for Economic Affairs and Climate Action.

Signing of an intergovernmental agreement

Another boost for Bornholm Energy Island: Robert Habeck, Federal Minister for Economic Affairs and Climate Action, and his Danish counterpart Lars Aagaard confirmed their signing of the agreement during the European energy ministers meeting in Luxembourg on Monday, 19th of June. The agreement between the Danish and German governments creates the conditions to realize the innovative power hub on Bornholm and several hundred kilometers of 525 kV direct current sea and land cables.

Stefan Kapferer, CEO of 50Hertz: "Bornholm Energy Island paves the way for a future in which offshore wind energy will no longer be accessed exclusively by individual countries via point-to-point connections. In the future, part of the offshore electricity produced flow to wherever the greatest demand is via offshore DC grids. The Bornholm Energy Island project will also be used for electricity to be traded between Germany and Denmark. This is economically viable and will increase both countries’ security of supply under new geopolitical circumstances.”

Thomas Egebo, CEO of Energinet: “For Denmark and Energinet, the deployment of very large-scale offshore wind farms and interconnectors is also an important part of politically mandated ambitions and wider plans to export both green electrons and green molecules via a future hydrogen backbone in Denmark. That is supporting the decarbonisation of Germany’s industrial sector. This joint project in the Baltic Sea and our projects in the North Sea will have an enormous impact on Europe’s energy transition.”

With Bornholm Energy Island Energinet and 50Hertz are not only doing pioneering work from a technical point of view. Negotiations between the two companies and their respective governments have also clarified ownership rights and the allocation of target renewable energy quantities. Under the agreement, both grid operators will equally bear the infrastructure costs for the project and also equally share the renewable energy target amounts. 50Hertz and Energinet will also split the congestion revenues linked to the power lines that will lead to Germany and Denmark equally.


Bornholm Energy Island is one of two Energy Islands being planned in Danish waters as a result of the Danish Climate Agreement adopted by the Danish Parliament in June 2020. Bornholm Energy Island will have a production capacity of 3 GW.


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