Denmark, Germany Ink Agreement on Bornholm Energy Island

The governments of Germany and Denmark said they have paved a new regulatory ground with the signing of an agreement for a cross-border project that will connect several wind farms via a single hub on the Danish island of Bornholm in the Baltic Sea.

The project, called the Bornholm Energy Island, is designed to deliver three gigawatts of electricity onshore to be distributed to around three million homes and businesses in Denmark and Germany. The project is owned by Danish state-owned power and gas transmission systems operator Energinet and German electricity transmission system operator 50Hertz.

“Denmark and Germany have agreed on sharing the costs to finance the support need for the offshore wind”, said a joint statement by the countries’ energy ministries.

“The project entails the first example of two countries sharing the support needed for an offshore wind farm and proves a landmark in the development of European cross-border offshore cooperation”, the statement added.

Energinet said separately “the agreement provides greater clarity on the political and economic framework for planning and coordination across the border”.

50Hertz said in its own statement the government agreement is the project’s “decisive building block”.

50 Hertz chief executive Stefan Kapferer highlighted, “The agreement between Germany and Denmark has an impact on the offshore industry across Europe, extending far beyond the Baltic Sea project Bornholm Energy Island. It is furthermore a strong European signal in geopolitically difficult times”.

A statement from the European Commission, which last year signed a grant agreement worth EUR 645.2 million ($770.68 million) for the Bornholm Energy Island, said the agreement between Berlin and Copenhagen “marks a first key delivery of the Energy Highways initiative set out as part of the European Grids Package published in December 2025”.

The project “will transform offshore wind energy from a national resource into a shared European resource for electrification”, added the Commission, which has touted the project as the world’s first hybrid direct current interconnector.

Project Progress

On September 4, 2025 Energinet and 50Hertz announced an award to Siemens Energy for the construction and turnkey delivery of four converter systems and other technical components on the Danish islands of Bornholm and Zealand and the German mainland. 

The contract “covers the design, the completion, transport, installation, testing as well as commissioning of the systems by the mid-2030s”, said a statement on 50Hertz’s website.

With the contract, the project is “moving from the planning and development stage to the implementation stage” after a “six-month transition phase during which the joint project had to be paused due to the need for political regulation between the two countries involved”, the owners said.

“These issues included the question of liability in case no electricity can flow to Germany through an international offshore grid connection because of a disturbance or due to maintenance”, Kapferer said. “Such a guarantee is the prerequisite for a successful tender for the wind farm areas off Bornholm in particular and, more generally, for an efficient offshore cross-linking between all countries bordering the North and Baltic Seas.

“The amendment of the Energy Industry Act (Energiewirtschaftsgesetz, EnWG) by the Federal Cabinet now also enables the connection of an additional wind farm in Danish waters to the German extra high voltage grid through the Ostwind 4 grid connection project planned by 50Hertz”.

50Hertz already executed a framework agreement with Danish manufacturer NKT late 2023 for the production and laying of the submarine and onshore cables between Bornholm and Mecklenburg-Western Pomerania.

“Following a Europe-wide tender and the approval by the Danish government, Energinet was now also able to order the cable connection between Bornholm and Seeland from NKT”, said the September statement.

The statement added the approval procedure in Denmark had been launched. Energinet and 50Hertz “are preparing for public hearings of the Danish environmental agency on Bornholm Island”, the statement said.

“The approval procedure for the cable routes through the Exclusive Economic Zone in Germany, the coastal waters as well as on land has not started yet”, the statement said. “Nevertheless, 50Hertz has started early public participation and informed the local population and the authorities of the planned location for a new substation with converter in the municipality of Kemnitz in the Vorpommern-Greifswald district”.

In its statement on the government agreement, Energinet said “technical preparations and regulatory processes” continue.

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