North South Interconnector

This project proposes the addition of a new 400 kV overhead line to our grid, connecting the electricity grids of Northern Ireland and the Republic of Ireland. It is also known in Northern Ireland as the Tyrone to Cavan Interconnector. When built, the project will start at a substation in Turleenan, Co Tyrone. It will then run into Co Armagh and then into counties Monaghan, Cavan and Meath.

October 2023

As the North South Interconnector has full planning permission, it will now proceed to the next phase of development. SONI continues to engage with landowners, local communities and key stakeholders as the project moves forward.

Construction of the project is due to start in 2024. ESB and NIE Networks have carried out site investigation boreholes, environmental and technical surveys at a number of tower locations along the route to gather information for the construction phase, to ensure compliance with the approved planning permission. At this stage, NIE Networks has begun procurement for construction and materials.

February 2022

The window to appeal the decision of the High Court in Belfast has now expired and SONI is pleased to have this certainty, as we move forward to deliver the project.

The North South Interconnector will be built and maintained by NIE Networks and SONI has supported NIE Networks in carrying out walkovers and borehole surveys. We’d like to thank everyone who helped us with this important work.

Procurement for the supply of materials for the construction of the overhead line is underway. Testing of the final pylon designs is being undertaken, with a view to construction beginning next year in order to have the project fully operational by 2026.

October 2021

The High Court in Belfast has upheld Planning Approvals for the North South Interconnector project. This follows a legal challenge to the approval granted by the Infrastructure Minister, Nichola Mallon MLA in September 2020.

SONI welcomes the decision to uphold the planning approvals for the North South Interconnector and commits to continue engagement with landowners and communities.

Read the full statement here.

September 2020

SONI welcomes the decision by Minister Mallon MLA to approve planning permission for the North South Interconnector, which will be a catalyst for Northern Ireland’s response to climate change, reduce consumer costs and provide a secure long term electricity supply for NI.

The project is a much needed high capacity and resilient link between the electricity grids in Northern Ireland and Ireland and will remove costly blockages on the network. It will allow for the flow of 900 MW of renewable electricity across the border, in both directions, enough to power 600,000 homes on green energy

Due to its economic, environmental and societal benefits, the North South Interconnector has received strong backing from the Department for the Economy, as well as from business, industry, academia, consumer and third sector organisations. Read the full statement here.

July 2019

SONI has submitted updated environmental information on the proposed North South Interconnector project to the Department for Infrastructure, as part of the planning process.

In the ‘Further Environmental Information 2019 addendum’, SONI presents a number of detailed technical environmental assessments, which were undertaken in 2019. 

These deal with issues such as ecology, the local landscape, the local community, transport and socio-economic impacts.

The report, which will now be considered by DfI, has concluded that there is no change to the environmental information previously submitted by SONI.

Read the main summary here and non-technical summary here.  

February 2019

On 08 February, the Department for Infrastructure conceded to a legal challenge against the planning permission. This challenge argued that planning approval could not be granted in the absence of an Infrastructure Minister.

However, in November 2018, the Secretary of State for Northern Ireland introduced new legislation. This gives Permanent Secretaries across the NI Civil Service the right to make key decisions when no Stormont Executive is in place. 

Given this, we are hopeful that the DFI will re-approve the planning permission for the North South Interconnector.

On 19 February, the Supreme Court in Dublin upheld planning approval for the southern section of the North South Interconnector, drawing the legal process to a close in the Republic Ireland.

Planning approval for the project was granted by An Bord Pleanála in December 2016. The southern element of the project has now cleared all planning and legal hurdles.

October 2018

SONI welcomes the findings of independent studies into the North South Interconnector commissioned by the Minister for Communications, Climate Action and Environment in the Republic of Ireland.

An International Expert Commission examined the technical feasibility and cost of undergrounding the interconnector. The findings support both SONI’s and the Irish grid operator, EirGrid’s, approach to the project, confirming that an overhead line is the best technical solution and the most cost efficient for consumers.

You can read more here.

January 2018

On 23 January 2018, the Department for Infrastructure approved planning permission for the North South Interconnector. The approval from the DFI comes after a positive recommendation from the Planning Appeals Commission (PAC) which reviewed the planning applications and carried out a Public Inquiry into the project; held in Armagh in February 2017. Planning approval for the southern element of the scheme was granted in December 2016.


November 2017

The Planning Appeals Commission (PAC) issued its recommendation on the outcome of the planning applications for the North South Interconnector to the Department for Infrastructure.
The PAC completed its Public Inquiry into the proposal in February 2017. It is expected that the Department for Infrastructure will consider the recommendation and announce its decision in the coming months.

February 2017

The Planning Appeals Commission held a Public Inquiry into our planning applications for the project at the Armagh City Hotel. During the Public Inquiry, the Commissioner set an indicative timeline for a recommendation by the end of the year.


June 2016

The Planning Appeals Commission held ‘Stage 1’ of its Public Inquiry in June 2016. This hearing looked at procedural and legal aspects of SONI’s planning applications.


Republic of Ireland status

This is a cross-border project. The section of the scheme in the Republic of Ireland is being handled by our sister company EirGrid. An Bord Pleanála, the Republic of Ireland planning body, granted planning approval for the project in the Republic of Ireland on 21 December 2016. You can read more about this here.