RTE and EirGrid advance Celtic Interconnector project with 575 km subsea transmission link between France and Ireland

Réseau de Transport d'Électricité (RTE) and EirGrid advanced the Celtic Interconnector project with the first French campaign to lay 98 km of subsea cables near Cléder, Finistère, marking a critical milestone in the 575 km, 700 MW interconnector linking France and Ireland. The €1.6 billion project, supported by a €530 million grant from the European Commission, will enable power exchange equivalent to 450,000 households and enhance grid resilience and renewable energy integration across Europe. The interconnector, recognized as a Project of Common Interest (PCI) by the EU, is scheduled for completion in 2028, with 90% of terrestrial civil works already finished and station conversion nearing completion. The project leverages Nexans' French-manufactured cables and the cable-laying vessel 'La Calypso,' which delivered two fiber-optic-equipped cables to Brest port in March 2026 for offshore installation. Local economic benefits are estimated at €13 million, while the interconnection will be the seventh for France and the first direct link between continental Europe and Ireland.

Counterparts (4)

Developer

Réseau de Transport d'Électricité (RTE)

company

Réseau de Transport d'Électricité (RTE) is the French electricity transmission system operator, responsible for operating, maintaining, and developing the high-voltage electricity transmission grid in mainland France. Its core mission is to ensure the security and reliability of electricity supply, facilitate the integration of renewable energies, and develop interconnections with neighboring countries.

Partner

EirGrid

company

EirGrid is the state-owned electricity transmission system operator (TSO) for Ireland, responsible for operating, developing, and maintaining the national grid. It also operates the electricity system in Northern Ireland through its subsidiary SONI. Its strategy focuses on integrating renewable energy, enhancing grid resilience, and developing international interconnectors to meet future energy demands and achieve climate targets.

supplier

Nexans

company

Nexans is a global provider of advanced cabling solutions and services, specializing in power transmission, distribution, buildings, and electric mobility. The company delivers critical infrastructure components, including record-setting subsea HVDC cables and systems for offshore wind farms and national grids globally.

Lender

European Commission

company

The European Commission is the executive branch of the European Union, responsible for proposing legislation, implementing decisions, upholding the EU treaties and managing the day-to-day business of the EU. It plays a significant role in infrastructure development through funding programs, policy initiatives, and regulatory frameworks.