Context
In July 2017, transmission system operator TenneT awarded Nexans the contract to supply and install the cables for the DolWin6 direct-current link. This project aims to transport electricity from the offshore wind farms of North Sea Cluster 3 from the DolWin Kappa HVDC converter station to the Emden/Ost onshore HVDC converter and transformer station. The project involved the installation of two parallel, XLPE-insulated 320 kV DC cables, each measuring 90 km in length, with a maximum output capacity of 900 MW. The project, valued at around 100 million euros, was completed in 2023 and represents one of Nexans Deutschland’s largest projects.
Challenges
The geographical location of the offshore wind farm presented challenges, as the cables must pass through the ecologically sensitive Wadden Sea. Additionally, the cables cross the island of Norderney, necessitating careful installation techniques to protect the environment and wildlife.
Key figures
900MW
Maximum output generated by wind turbines
2x320kV
Maximum voltage of the cables
2x90km
Length of offshore cables
Nexans implication
Nexans was responsible for all stages of the project related to the cable system, including design, manufacture, logistics, and installation. The Group supplied submarine XLPE-insulated 320 kV DC cables, manufactured in Norway, accessories, and installation services. Additionally, Nexans installed a fiber-optic cable for data transfer.
Land cables, produced in Belgium, were installed between Hilgenriedersiel and Emden at a distance of roughly 45 kilometers.
Low-loss high-voltage and ultra-high-voltage cables from Nexans enable grid operators to expand their grids in a way that achieves the best possible results in terms of efficiency and conservation of resources, and thereby to lay the groundwork for the energy supply of the future.
I am delighted that TenneT has awarded us the contract for this important link. With DolWin6, we are responsible for all stages of the project relating to the cable system, including design, manufacture, logistics and installation, and after previous projects such as Beatrice, Italy-Montenegro and NordLink, we once again have the chance to demonstrate our expertise in high-voltage direct-current transmission.
Managing Director, Nexans Deutschland