A major new electricity interconnector linking Ireland and Wales is now up and running and has been officially launched.

The 500-megawatt Greenlink interconnector will enable the importation of electricity into Ireland from Britain, and the export of any surplus renewable electricity from Ireland. It is considered one of Europe’s most important energy infrastructure projects and took ten years to deliver, between its development and construction.

Sub-sea cable laying off Pembrokeshire coast. Photo: Jan De Nul.

The new 320kV interconnector – comprising two high voltage direct current (HVDC) subsea cables and associated converter stations – connects at substations on National Grid’s and EirGrid’s networks. It involved the laying down 160km-long high voltage electricity cable under the Irish Sea between Pembrokeshire in Wales and Great Island in Wexford.

The cable is critically important in achieving Ireland’s climate commitments as it enables the importation of lower carbon electricity from the UK and beyond. The greenhouse gas emissions associated with the supply of electricity from the UK to Ireland is not counted as emissions in Ireland.

The UK supplied a total of 14.4% of all the electricity consumed in Ireland through electricity interconnectors during the first six months of 2024. That was up 84% on the same period in 2023. This means electricity imports from the UK are now the third-largest source of electricity in Ireland, after electricity generated from wind and natural gas.

Converter stations located adjacent to the substations at each end of the interconnector convert its direct current (DC) electricity to alternating current (AC) for use when imported onto each country’s grid, with the reverse process taking place to export power over the link.

The launch of the Greenlink interconnector follows on from the UK Prime Minister and the Irish Taoiseach announcing closer collaboration on energy production at the first of a series of annual summits between the two countries in March 2025. The two prime ministers announced closer collaboration on subsea energy infrastructure to “harness the full potential” of the Irish and Celtic seas as part of ongoing efforts to reset post-Brexit relations.