Deep-Water Milestone: Nexans Sets World Record with 530m Subsea Installation in Norway

Nexans, in partnership with Norway’s transmission system operator Statnett SF, has officially completed a landmark project in the Fensfjord, setting a new world record for the deepest installation of a 420 kV HVAC (High-Voltage Alternating Current) subsea cable.

The project reached a staggering depth of 530 metres below sea level, a technical feat that pushes the boundaries of subsea engineering. The installation is a critical component of the expansion of the high-voltage power link between Haugsvær and Lindås, designed to double transmission capacity and reinforce grid reliability for the city of Bergen and its surrounding industrial hubs.

A Record-Breaking Feat of Engineering

The Fensfjord crossing is notorious for its challenging underwater geography. To achieve the 530-metre record, Nexans had to navigate:

• Extreme Gradients: Fjord slopes reaching up to 55 degrees, requiring the cables to be securely anchored to the seabed to ensure long-term stability over a 40-year lifespan.

• Massive Scale: The installation involved 7.8 km of high-voltage subsea cable, which also incorporates fiber-optic elements for real-time monitoring and communications.

• Complex Landfalls: At the Iledalsvågen side, shallow waters required the cable to be floated for 1.5 km using buoyancy elements before being precision-lowered into its final position.

Precision Operations

The mission-critical marine operations were led by the CLV Nexans Skagerrak, the company’s specialized cable-laying vessel. The project also utilized specialized workboats and ROVs (Remotely Operated Vehicles) to manage the delicate placement of approximately 180 concrete mattresses used to stabilize the seabed foundation.

"This project required precision engineering and installation at extreme depth and in demanding fjord terrain," stated Peter Drakele, Senior Project Manager at Nexans. "Reaching 530 metres with 420 kV HVAC technology represents a significant technical achievement."

Powering the Future

With the project now fully energized and certified, it stands as a cornerstone of Norway's long-term energy security. By increasing the capacity of this key fjord link, Nexans and Statnett are ensuring a stable electricity supply for over 420,000 residents and the growing energy demands of Norway's industrial sector.

This achievement marks a "triple crown" year for Nexans, following their recent 2,150-metre depth record in Italy and a 3,000-metre deep-water sea trial earlier this year.