Review states North South Interconnector should proceed as an overhead line

An independent review of the planned North South Interconnector has found that the only viable option for the project to proceed with is to use overhead pylons.

This review released by Government this evening accepts the findings of previous reports including the 2018 Expert Commission that indicated that the North South Interconnector should be constructed as planned as an overhead line.

The North-South Interconnector Project Independent Experts Review which commenced in 2021 distilled five options down to two realistic options - an underground High Voltage (400kv) DC (HVDC) interconnection and the overhead High Voltage AC (HVAC) cable.

The Review concluded that undergrounding or embedding the HVDC cable would delay commissioning of the Interconnector by at least five years and would add approximately €120m of additional costs compared with the currently planned AC Overhead Line (OVL).

"The Commission’s own estimate of the extra capital cost of an embedded High Voltage DC line (HVDC) for a North-South interconnection compared with the planned 400kV OHL is €270m giving an estimated total extra cost of €390m.

While the Expert Review regarded undergrounding as a credible option, it said there are a number of aspects of the potential use of embedded HVDC in the context of the interconnection between Northern Ireland and the Republic that "would require careful consideration".

"Among these issues is that a number of parties with which the Commission has consulted have expressed the need for economic development in the areas through which the planned North-South interconnector passes. They have pointed specifically to the possibility of attracting investment in new industrial or commercial facilities that have a need for significant amounts of electrical energy, in particular data centres. However, development of a North-South Interconnector as embedded HVDC system would not achieve this."

The Review also looked at the option of less intrusive overhead pylons that would line the landcsape of Monaghan, Cavan and Meath but noted that the project costs would double as a result.

In a statement this evening EirGrid welcomed the Review findings.

"This Review accepts the findings of previous reports including the 2018 Expert Commission that indicated that the North South Interconnector should proceed as planned as an overhead line.

"The North South Interconnector is critical for the security of electricity supply across the island of Ireland; to support social and economic growth in the Northeast region; and enable Ireland to reach its renewable energy targets.

"As the project has full planning permission in Ireland and Northern Ireland it will now proceed to the next phase of the project. EirGrid will liaise closely with ESB Networks, which will build the Irish portion of the project and the regulator, the Commission for the Regulation of Utilities on the next steps.

"There will be full engagement with landowners, local communities and stakeholders along the route as we proceed with the project."

The aim of the North South Interconnector is to connect the electricity grids of Ireland and Northern Ireland. The 400 kV line will run through counties Monaghan, Cavan and Meath in Ireland, and Armagh and Tyrone in Northern Ireland.

According to EirGrid, the interconnector "will underpin the efficient operation of the all-island electricity market, fixing a bottleneck that costs millions of euros every year and applying downward pressure on electricity prices."

In 2012, an earlier independent report into the project was published by a Government-appointed International Expert Commission. Today’s study is an update to the 2012 and 2018 reports and examines possible changes in technology and costs which may have taken place in the intervening years.

The Minister for the Environment, Climate and Communications, Eamon Ryan, commissioned a further short review to assess if the overall findings from the 2018 report were still valid.

The pylon project, planned to run 135km from Meath to Tyrone, has seen huge local opposition in parts of Cavan, Meath and Monaghan for a number of years.

More to follow...