What is the technical capacity and purpose of the Celtic Interconnector?

The Celtic Interconnector is a 700 MW HVDC subsea link designed to facilitate bi-directional electricity trade between Ireland and France. It allows Ireland to export surplus renewable generation to continental Europe while importing power to maintain grid stability during low-wind periods.

Why is this project considered strategically critical for the European Union?

The project ends the post-Brexit physical isolation of the Irish electricity network from mainland Europe and deepens the integration of the EU internal energy market. It enhances security of supply, fosters market competition, and aligns with the bloc's decarbonization targets under the European Green Deal.

When is the Celtic Interconnector scheduled to enter commercial service?

Following the completion of offshore laying, terrestrial converter works, and system testing, the interconnector is scheduled to become fully operational in 2026. This timeline provides critical transmission capacity ahead of Ireland's next wave of offshore wind deployment.

Offshore Energy · May 29, 2026 (May 29) · 1 min read

WATCH: Onshore cabling completed for Ireland’s first direct energy link to Europe

Analysis

AI-assisted analysis · reviewed by Yuri Kan

Project developers have successfully finalized the onshore cable laying in Ireland for the Celtic Interconnector, marking a pivotal milestone in creating the island's first direct electricity connection to mainland Europe via France. This 700 MW high-voltage direct current (HVDC) infrastructure ends Ireland's post-Brexit energy isolation from the European Union single market. The link will enhance grid stability, mitigate renewable curtailment, and provide critical bi-directional capacity between Ireland and the continent.

Key Facts

Onshore cable installation activities have concluded in County Cork, Ireland, for the landmark Celtic Interconnector project.
The 700 MW high-voltage direct current (HVDC) link will stretch approximately 575 kilometers between Ireland and the Brittany coast in France.
Subsea cable operations represent roughly 500 kilometers of the overall route across the Celtic Sea.
The project is jointly developed by Irish transmission system operator EirGrid and its French counterpart Réseau de Transport d'Électricité (RTE).
With an estimated total capital expenditure exceeding €1.6 billion, the European Union is supporting the project with €530 million from the Connecting Europe Facility (CEF).
Once operational, the link will have the capacity to power approximately 450,000 homes while enabling direct trade within the EU internal energy market.

Background & Context

Following the United Kingdom's departure from the European Union, Ireland's power grid was left physically disconnected from direct EU electricity infrastructure, relying exclusively on interconnections via Great Britain. As Ireland rapidly scales up its onshore and offshore wind generation capacity, integrating subsea HVDC links has become essential to export surplus renewable power and import continental electricity during periods of low generation. The Celtic Interconnector was designated a European Project of Common Interest (PCI) to resolve this vulnerability and bolster regional energy security.

Market Impact

The completion of onshore civil works shifts operational focus to complex subsea cable laying and converter station integration, substantially de-risking the project delivery schedule. Strategically, the link integrates Ireland directly into the EU wholesale electricity market, which should exert downward pressure on wholesale power prices and lower carbon emissions through efficient cross-border dispatch. For European transmission operators, this project provides a benchmark in delivering complex, multi-jurisdictional subsea HVDC interconnectors under inflationary supply chain conditions.

What to Watch

Marine cable installation and offshore jointing across the Celtic Sea will proceed through the upcoming weather windows alongside converter station commissioning in Knockraha (Ireland) and La Martyre (France). The Celtic Interconnector remains on track to achieve mechanical completion and commence commercial operations by 2026. Market participants will be monitoring the allocation of initial transmission capacity and the integration of the route into EU day-ahead market coupling mechanisms.

Frequently Asked Questions

What is the technical capacity and purpose of the Celtic Interconnector?: The Celtic Interconnector is a 700 MW HVDC subsea link designed to facilitate bi-directional electricity trade between Ireland and France. It allows Ireland to export surplus renewable generation to continental Europe while importing power to maintain grid stability during low-wind periods.
Why is this project considered strategically critical for the European Union?: The project ends the post-Brexit physical isolation of the Irish electricity network from mainland Europe and deepens the integration of the EU internal energy market. It enhances security of supply, fosters market competition, and aligns with the bloc's decarbonization targets under the European Green Deal.
When is the Celtic Interconnector scheduled to enter commercial service?: Following the completion of offshore laying, terrestrial converter works, and system testing, the interconnector is scheduled to become fully operational in 2026. This timeline provides critical transmission capacity ahead of Ireland's next wave of offshore wind deployment.

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