650 MW
transmission capacity
1 km
of cable replaced during repair
Partnership
Fingrid
Market
Subsea interconnection
Location
Baltic Sea
Context
The Estlink 2 subsea interconnector is a strategic high-voltage electricity link connecting Finland and Estonia, enabling cross-border energy exchange and strengthening security of supply across the Baltic region. Commissioned in 2014, this 650 MW interconnector includes approximately 145 km of subsea cable infrastructure.
In December 2024, the cable system suffered damage, threatening regional grid stability and requiring immediate intervention. Nexans was contracted by Fingrid, Finland’s transmission system operator, to carry out a fast-track repair operation and restore the link.
Challenges
The project involved several critical challenges:
- Urgency: Rapid mobilization was required to restore a key energy corridor.
- Complex offshore operations: The damaged cable section was located subsea, requiring precise intervention in a demanding marine environment.
- Logistics & coordination: Equipment, spare parts, and technical teams had to be mobilized across multiple locations within tight timelines.
- System integrity: Ensuring full compatibility and reliability of the repaired section with the existing infrastructure.
- Operational continuity: Aligning repair works with Fingrid’s operational constraints to minimize disruption.
650 MW
transmission capacity
145 km
total subsea cable length
1 km
of cable replaced during repair
December 2024
damage occurence
Early 2025
Engineering & IMR mobilization initiated
May 2025
offshore repair completed
Nexans’ implication
Nexans played a central role throughout the entire repair lifecycle, demonstrating its expertise in subsea Inspection, Maintenance, and Repair (IMR) operations.
Engineering & Project management
- Early engagement with Fingrid to assess damage and define the repair strategy
- Deployment of specialized IMR engineering teams
- End-to-end project coordination ensuring alignment with grid requirements.
Cable & Technical scope
- Replacement of a 1 km section of high-voltage subsea cable (HVAC interconnector type)
- Use of pre-qualified spare cable stock originally manufactured by Nexans
- Execution of offshore jointing operations, a highly specialized process ensuring electrical and mechanical continuity
- Comprehensive testing and validation of all components prior to installation.
Facilities & Logistics
- Mobilization of materials from Fingrid depots to Nexans’ Halden, Norway facility, a key center for subsea cable expertise
- Preparation and testing of cable systems and jointing equipment at Halden
- Deployment of a specialized cable repair vessel, equipped with:
- Jointing tools and accessories
- Testing and monitoring systems
- Spare cable and repair components.
Offshore execution
- Safe and efficient offshore campaign conducted in May 2025
- Precise removal of damaged cable section and installation of replacement segment
- Completion on schedule and without incident, ensuring rapid return to service.
This project highlights Nexans’ ability to combine advanced cable technology, dedicated facilities, and offshore operational excellence to restore critical infrastructure under tight timelines.
This successful repair demonstrates our readiness and capability to respond fast and deliver—where it matters most. Nexans leads the world in high-voltage subsea IMR because we combine deep technical expertise with operational discipline, integrated systems thinking, and a track record of execution. From planning to offshore jointing, we know what it takes to get critical infrastructure back online—safely, reliably, and on time.
EVP PWR-Transmission Business Group, Nexans
We appreciate Nexans’ strong commitment and technical expertise throughout the planning and execution of this repair. The interconnector plays a key role in maintaining security of supply and energy cooperation in the region. Together, we’ve ensured that Estlink 2 can return to operation safely and on schedule.
Unit Manager, Fingrid
Testimonial of Timo Kiiveri, Executive Vice President of Fingrid
