Jan De Nul has concluded the 2025 transport and installation campaign of three HVAC grid connection cables at Tennet’s DolWin Kappa platform in the German North Sea.
When finalised, these cables will ensure the transport of almost 660 MW of renewable electricity from two offshore wind farms. Jan De Nul said this equals the energy needed to power 800,000 German homes.
Jan De Nul and Hellenic Cables were responsible for design, production, transport, installation and protection of three 155kV HVAC cables with a total length of 37 kilometres. These cables provide a stable connection from the offshore wind farms Nordseecluster One and Two to the offshore converter station DolWin Kappa.
The cable laying vessel Isaac Newton transported the three 155kV cables from Hellenic Cables’ submarine cable plant in Corinth, Greece. The vessel installed the cables between the Tennet offshore convertor station DolWin Kappa and the two offshore wind farm locations of Nordseecluster One and Two.
At crossings with other subsea infrastructures, the vessel installed concrete mattresses.
The multi-purpose vessel Adhémar de Saint-Venant buried the cables along the entire cable routes using her trencher.
During the past two weeks, the rock installation vessel Simon Stevin has installed about 25,000 tonnes of rock berms to ensure the protection of the HVAC interconnector cables on the seabed. These works conclude the campaign of 2025 at DolWin kappa.
In the spring of 2026, the last connection and testing works are planned, after the installation of the Nordseecluster One and Two stations.
