A new phase in Ireland’s decarbonisation journey opened earlier this month with the first auction for offshore wind farms under the Renewable Energy Support Scheme. The winning projects are expected to provide up to 2.5GW of renewable energy to the Irish grid – halfway to meeting the Government’s target of 5GW of offshore wind on the grid by 2030.
Separately, EirGrid has announced the commencement of a consultation process in relation to the development of Ireland’s first offshore electricity substations which will connect renewable energy off the south coast to the national grid. The announcement was made at the opening in April of the grid operator’s new Cork office.
The office will serve as a base for two strategic initiatives: the offshore grid development project and the Celtic Interconnector linking Cork with France.
Developed by EirGrid and its French counterpart, Réseau de Transport d’Electricité, the Celtic Interconnector is a 700-megawatt high-voltage submarine power cable linking Cork and the northwest coast of France.
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The interconnector will be the first power connection between Ireland and mainland Europe and will be able to import and export enough electricity to power 450,000 homes. Construction work is scheduled to begin next month.
The offshore substations project is part of EirGrid’s Shaping Our Offshore Energy Future programme that will mark the first step in the development of an offshore electricity grid for Ireland. EirGrid will construct two new offshore substations as well as the cables and infrastructure linking them to the onshore grid. The substations will connect up to 900MW of electricity from wind turbines delivered by private developers, producing enough electricity to power almost one million homes.
EirGrid chief infrastructure officer Michael Mahon explains an important difference between the onshore and offshore grids. EirGrid will own and operate the assets offshore whereas it is the operator of the onshore grid. “The first auction is based on projects which developers have been working on for more than 10 years,” he says.
“These are mainly on the east coast with one on [the] west coast. The auction will determine who gets to build wind farms.
“Those developers will develop the grid infrastructure in those areas and transfer the assets to EirGrid. EirGrid will build, own and operate the assets off the south coast.”
These substations are part of what is known as phase two of Ireland’s offshore wind development programme. Overall, the project will involve the construction of an offshore substation off the coast of Waterford or Wexford; an offshore substation off the coast of Cork; a connection between the offshore substations and existing substations onshore involving both undersea and underground electricity cables; and the construction of new substations near to existing substations onshore.
The views of local communities and environmental considerations, along with onshore grid capacity and need for electricity, will be among the primary considerations when deciding on the locations for the new substations, according to Mahon.
No decisions have been made on where the offshore substations will be located or how and where they will connect to the national electricity grid onshore, he points out.
“Consultation and engagement are hugely important. That’s why we are embarking on an extensive public engagement process that will seek the views of local communities, businesses and industries on how we can progress the delivery of offshore grid infrastructure in a way that takes appropriate consideration of the needs and opinions of all stakeholders.”
Capacity and demand factors need to be taken into account to ensure the power is capable of being used. “Cork’s peak demand is typically 250MW while Dublin’s is 1,800MW,” Mahon explains. “Projects being developed under our Shaping Our Electricity Future plan will enable the export of 350MW from the Cork area.”
The offshore substation currently under consideration off the coast of Cork would have the capacity to deliver 450MW to the onshore grid through a new substation in the Cork area. However, it is not planned to increase the export capacity beyond 350MW and the 100MW in additional power would be available to new industry in the Cork area, including green hydrogen production plants which may be developed to exploit the availability of renewable power in the area.
The other substation will connect to a substation in Great Island in Wexford.
The consultation process kicks off in June with a series of face-to-face public information events in a number of venues across Cork, Waterford, and Wexford. “This element of the consultation process is purely informational,” says Mahon. “Later this year we will probably have more engagement in relation to possible onshore and offshore locations for the substations.”
Once that consultation process is complete, it is hoped that environmental and geotechnical surveying will begin offshore early next year with a view to obtaining the necessary consents by the end of 2025 with construction commencing in late 2027 or early 2028.