Nexans Completes Record-Depth Subsea Cable Project in Norway

Nexans and Statnett have completed a 420 kV subsea cable project across the Fensfjord in western Norway, strengthening power supply to Bergen and surrounding industrial areas.

The project, awarded in 2022, included the engineering, manufacturing and installation of two high-voltage HVAC subsea cables spanning about 7.8 km between Haugsvær and Lindås, linking the Mongstad area to Iledalsvågen.

The new connection doubles transmission capacity across the fjord and forms part of broader efforts to reinforce Norway’s high-voltage grid as energy demand rises.

Nexans said the project reached full completion following energization and final certification, after installation work carried out in 2025.

One of the key technical challenges was the fjord’s depth, with the cable route reaching 530 meters below sea level, setting a world record for installation depth for a 420 kV HVAC subsea cable.

The steep seabed terrain, with slopes of up to 55 degrees on the Mongstad side, required anchoring solutions to ensure long-term stability over an expected 40-year operational life.

Installation also involved complex shallow-water operations at the landfall site, where cables were floated over a distance of around 1.5 km using buoyancy systems before being lowered into position. The seabed was stabilised with approximately 180 concrete mattresses and pipe mats.

Marine operations were carried out by the cable-laying vessel Nexans Skagerrak, supported by specialised vessels and onshore teams.

“This project required precision engineering and installation at extreme depth and in demanding fjord terrain. Reaching 530 meters with 420 kV HVAC technology represents a significant technical achievement. Most importantly, we delivered safely, on schedule and in close collaboration with Statnett,” said Peter Drakele, Senior Project Manager at Nexans.

“The Fensfjord expansion demonstrates Nexans’ ability to execute complex high-voltage subsea projects in challenging environments. Strengthening grid capacity in Western Norway is vital for both communities and industry, and we are proud to contribute to Norway’s long-term energy security,” added Lars Eriksen, CEO of Nexans Norway.

The project supports long-term electricity reliability in the region and prepares the network for future demand growth and energy developments.