The Celtic Interconnector high-voltage power cable linking the south coast of Ireland with the northwest coast of France came a step closer to reality late last year with the signing of key technical and financial agreements by EirGrid and its French counterpart Réseau de Transport d’Electricité (RTE).
The €1.6 billion project involves the construction of a 575km interconnector running from east Cork to northeast Brittany which will be capable of carrying 700MW of electricity, the equivalent of supplying power to about 450,000 homes. It will be the first interconnector between Ireland and continental Europe. France already has 50 electricity connections with its European neighbours.
The interconnector will comprise onshore and offshore elements, with a 500km underground cable running from Brittany to Cork and a further 35km on land in Cork.
The submarine electricity cable will land at Claycastle Beach, near Youghal in east Cork, and an underground cable will run inland to a converter station at Ballyadam to the east of Carrigtwohill. The final connection will be by underground cable from Ballyadam to a substation on the national grid at Knockraha 10km away.
Contracts
Two contracts were signed in Paris in November: one with Siemens Energy for the development of converter stations in Ireland and France, and the other with French cable manufacturer Nexans, which will design and install the 575km cable between the two countries.
Agreements were also signed for €800 million of financing to be provided by the European Investment Bank, Danske Bank, Barclays and BNP.
“The Celtic Interconnector is a key part of Eirgrid’s strategic goal to transform Ireland’s power system and increase the use of renewable electricity,” says Eirgrid’s chief infrastructure officer Michael Mahon.
“When we have an excess of renewables on the system, we can export that power to the European grid. When we have a shortfall, we can import up to 700MW through the interconnector.
“One of the challenges we have as we increase the amount of renewables on the system is that there might be lots of wind one day and very little the next. We need backup when it drops off and this project will help provide that. We also have the benefit of being able to export energy when we have a surplus in the system.”
There may also be consumer benefits. “It may also help bring down the cost of electricity as the price of electricity in Europe is cheaper than in Ireland,” Mahon adds.
Planning for the project began some time ago. “We’ve been on the journey for a number of years,” says Mahon. “We got approval from the regulators in both jurisdictions back in 2019 and applied for a grant for it from the European Commission. We received €530.7 million under the Connecting Europe Facility.”
The Connecting Europe Facility (CEF) is an EU funding instrument that supports the development of high-performing, sustainable and efficiently interconnected trans-European networks in the fields of transport, energy and digital services.
Since then, consents have been obtained from authorities in Ireland, the UK and France for the cable to pass through their territorial waters.
Construction stage
“We are now moving to the construction stage, and onshore work should start in Cork and Brittany this year,” says Mahon. “Cable manufacturing has commenced. Work will begin on laying it in the summer of 2025 and should finish in the summer of 2026. That will involve a real engineering feat. It is only possible to lay the cable in summer months due to weather conditions at sea.
"Also, it has to be buried under the seabed. And where it has to be laid on top of rock it has to be covered to protect it from anchors and so on. The cable-laying vessels use smart technology to enable them to operate in waters up to 110 metres in depth. It should be fully operational by the end of 2026, and we plan to take it over in the first quarter of 2027 when it has proved itself.”
That relatively long timescale will facilitate community engagement. “We have engaged in intensive consultation with communities in Cork and we are going to roll out a community benefit fund as part of the project. At €2.4 million it’s our largest community fund to date. We have established a community forum that will guide us on how we distribute the fund. It will focus on community, biodiversity and sustainability projects.”
Looking ahead to the longer term, Mahon believes the project and others like it in future will help Ireland maximise the potential of its offshore wind resources.
“Ireland won’t be able to consume all that power and the best way to utilise it is to sell it to Europe. Ireland could become the Saudi Arabia of Europe for offshore wind.”
