The transmission system operators (TSOs), Energinet and 50Hertz, have placed a joint order with Siemens Energy for the construction and turnkey delivery of four converter stations and other technical components that will connect the Bornholm Energy Island project to the mainland grids of Denmark and Germany.
The major contract covers the design, completion, transport, installation, testing, and commissioning of the systems by the mid-2030s.
Two converter stations and the high-voltage alternating current (HVAC) station will be located at Aakirkeby on Bornholm, while the other stations will be built at Lindehøj on Zealand and in the Kemnitz municipality in the district of Vorpommern-Greifswald in Germany.
The power hub on Bornholm is intended to take on electricity from the future offshore wind farms off the coast, raise it to a DC voltage level of 525 kV, and then make it available to consumers in Germany and Denmark as needed via submarine and onshore cables.
“We would like to thank the Federal Government for clearing formerly unsolved regulatory issues so shortly after taking office. 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. 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,” said Stefan Kapferer , Chief Executive Officer of 50Hertz.
“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.”
The total cost for the overall Bornholm Energy Island project is currently around EUR 7 billion. The European Union granted a subsidy of EUR 645 million as part of its Connecting Europe Facility (CEF) programme to Energinet.
The resources are primarily intended to reduce the Danish part of the investment costs, as a larger portion of the renewable energy generated by the wind farms off Bornholm will also flow to Germany.
The power cable between Bornholm and the future substation near Lubmin on the shore of the Bay of Greifswald will have a capacity of 2 GW, while the power cable to Zealand will have 1.2 GW.
Recently, Energinet signed a contract with NKT for the delivery of a high-voltage direct current (HVDC) power cable system for the offshore interconnector linking the Bornholm Energy Island to the power grid on Zealand in Denmark.
The Danish and German TSOs, Energinet and 50Hertz, started the approval procedure in Denmark and are preparing for public hearings of the Danish environmental agency on Bornholm Island. The approval procedure for the cable routes through the German Exclusive Economic Zone, the coastal waters, and on land has not started yet.
In addition, 50Hertz has started early public participation and informed the local population and the authorities of the planned location for a new substation with a converter in the municipality of Kemnitz in the Vorpommern-Greifswald district.