Denmark, Germany open 400 MW power cable linking Baltic Sea wind farms

London — Germany and Denmark have officially opened the world's first hybrid wind interconnector in the Baltic Sea, grid operators 50Hertz and Energinet.dk said Oct. 20.

With tests still ongoing on the asset, however, commercial operation of the Combined Grid Solution (CGS) is not scheduled until December.

Two 200 MW subsea cables link the offshore substations of Denmark's 600 MW Kriegers Flak offshore wind farm, set to start in 2021, with Germany's 288 MW Baltic 2 operational wind farm.

Both are already connected to the national grid.

CGS would allow offshore wind generation from the wind farm to both Denmark and Germany and, when the wind does not blow, can be used for electricity trade between the two countries.

The cost for the project was pegged at Eur300 million ($350 million).

Germany's economy and energy minister Peter Altmaier described the interconnector as a "European lighthouse project for cross-border cooperation in offshore wind" with future pan-European offshore wind projects a key focus during Germany's rotating EU presidency.

The head of Danish TSO Energinet Thomas Egebo said CGS was an important milestone for the next projects including plans for two Danish energy islands in the Baltic and North Sea surrounded by 2 GW offshore wind turbines each with direct power links to neighboring states.

The CEO of Belgian TSO Elia Chris Peeters described the technology as an "efficient investment" allowing access to renewable energy at lower cost. Elia owns 80% in 50Hertz, with the German state holding the remainder.

Denmark and Germany have been leading wind power for over a decade with existing cross-border cables in the wind-rich border region often congested leading to a complaint by Denmark to make more transmission capacity available.

Available transmission capacity on the DK1 to Germany (Tennet bidding zone) border was lifted to at least 1.1 GW for 2020 by a joint governmental declaration 2017 after available transmission capacity on the 1.8 GW border fell below 0.2 GW in 2016.

The new 700 MW Cobra cable linking Denmark directly with the Netherlands since 2019 is currently offline to December due to a cable fault.

Nordic power prices are generally the lowest across Europe, but Denmark's DK2 zone including Copenhagen at times has a higher price than the market coupled CWE region with the majority of Nordic transit flows directed through the DK1-Tennet border.

The 600 MW Kontek HVDC cable has been operating since 1995 between DK2 and the 50Hertz bidding zone also using the Bentwisch substation in Northeast Germany.