Deployment of Nexans XLPE cable for the Celtic Interconnector—a project described as one of Europe’s most ambitious energy infrastructure projects—has finally entered the next key cable stage of an initiative that will not see commissioning until 2028.

A press release and media reports said the €1.6 billion project will link the Irish and French electricity grids with what will be the world’s longest XLPE interconnector. The official length is about 575 km in total, with some 500 km being XLPE subsea cable linking Ireland to France. The remainder of the cable will be used underground between converter stations and transmission grids in Cork and Brittany. The long-planned subsea installation began in the summer of 2025, and that project step is now expected to be completed by year’s end.

The project, recognized as a Project of Common Interest by the European Union, will enable Ireland’s first direct energy connection to continental Europe. Nexans was awarded the contract in 2022 to supply and install the cable. Construction started in 2023, with works progressing on pace on both land and sea. Converter stations in Cork County and Brittany are nearing completion, and significant portions of land cable ducting and transformers have been delivered.

Final commissioning, however, is still a long way off. Originally planned to be completed in 2027, the date has been pushed back to 2028 for multiple reasons, reports EirGrid, Ireland’s state-owned electricity transmission system operator. Substantial progress, however, has been made, and work is now physically underway off Ireland’s southeast coast with key cable-laying and burial activities. The remaining steps include completing system integration, rigorous operational testing, trial runs, and final certification—delays for such complex HVDC subsea projects are common industry-wide.

Co-funded by the EU’s Connecting Europe Facility, the project received more than €530 million in grants in recognition of its strategic impact.