New submarine cable secures power supply at Kobbvatnet

Aug 27, 2025

Statkraft will have a new high-voltage submarine cable installed in the lake Kobbvatnet at Kobbelv hydropower plant in Nordland. The new solution replaces a previous land-based power line that was destroyed in a landslide on the mountainside.

The cable installation secures the power supply in the area - while reducing vulnerability to natural events.

The cable, a TXRE 24kV 3x95mm² Gs(48) R3.2+Zn, is equipped with 48 integrated fibre elements. A total of 2,605 metres of cable was delivered from Nexans' factory in Rognan - delivered on a 3.6 metre steel drum with a total weight of around 25 tonnes.

Trouble-free installation after a successful FAT

The installation is being carried out by our customer Vindra AS, which was also present during a successful FAT (Factory Acceptance Test) at the Nexans plant in Rognan on 2 June. They were joined by representatives from Statkraft, the project's end customer.

Per Gunnar, Project Manager at Vindra, had this to say about participating in the FAT:

- "It was a very nice experience to come to Rognan to participate in FAT. We were well received and given a thorough introduction to the activities that were planned.

From left: Tor Gunnar Evensen (Statkraft), Per Gunnar Tryggestad (Vindra), Bella Abrahamyan (Nexans) and Bård Lillehaug (Nexans).

The cable is specially designed to withstand demanding underwater conditions, and also has a blue outer sheath made of plastic material that is approved for use in drinking water.

- We installed the cable directly from a CRD system. The cable behaved as expected and there were no technical installation challenges at any point in the project. The blue colour of the outer sheath also provided a nice contrast to the dark surroundings in the depths, which provided good conditions for the ROV personnel who had good visual contact with the cable during installation.

Norwegian-made cable - delivered locally

It is particularly positive that the cable in this project is both manufactured and installed locally - only ten miles from the Nexans factory in Rognan. The factory in Rognan often produces cables that are shipped and installed internationally, but the fact that it is now such a short distance to the final destination has created a lot of internal pride.

And it's an advantage to have local expertise readily available throughout the various phases of a project.

- We started looking at this project together with Nexans at a very early stage. Nexans' good understanding of the scope of the project helped to ease some of the challenges we saw in the project, perhaps especially related to developing a cable design that enabled ‘ordinary’ transport of cable from Rognan to Kobbvatnet, concludes Per Gunnar.