An independent expert review has backed a 2018 commission decision that the North-South electricity interconnector should be built above ground.
The review was commissioned by the Government two years ago to assess if the findings of the earlier conclusions of the International Expert Commission remained valid in light of changes to technology and costs.
The 138km long 1500MW interconnector will link electricity transmission networks here with those in the north.
The 400 kV line will run through Monaghan, Cavan and Meath in the south, and Armagh and Tyrone in the north.
The infrastructure will more than double the amount of power transferring between north and south, boosting security of supply here.
It will also enable a high level of renewable energy to be accommodated on the national grid.
The latest review concludes that the interconnector cannot be put underground because it would not be as reliable and stable as it would need to be.
This would lead to substantially less savings and benefits to the consumer.
It is forecast that €87m in savings and benefits will be realised from the interconnector each year by 2030 through network efficiencies across the Single Electricity Market.
The project has received planning permission in both jurisdictions and will now move to construction.
It is expected that it will be finished by 2026.
National grid operator Eirgrid said it acknowledged the publication by the Government of the latest independent review.
"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," it said.
It added that as it moves towards the construction phase, there will be full engagement with landowners, local communities and stakeholders along the route.
'A disaster for Co Meath'
Meath West TD Peadar Tóibín has described the findings of the review as "a disaster for county Meath".
He said there is "no consent among the community along the curtilage of the proposed project" for it to go ahead over ground.
Mr Tóibín said that there has been massive opposition to the plan.
"It's 15 years in the making and it's taking so long because of Government's determination to put it over ground," he said.
He also called on the Government to reverse the decision.
Meanwhile, Fianna Fáil Senator Shane Cassells said that "the report acknowledges the reality of putting the line underground but speaks to the benefits of overground".
He asked what price was being put on our landscape and heritage and questioned if Green party Minister Eamon Ryan thought it was beneficial "to see 300 pylons desecrating the most historic landscape in Ireland".
Senator Cassells said it was "absolutely laughable" that it's projected the interconnector will be built inside three years.
"I hope that their independent expert included a piece in his report on how to deal with Meath people defending their land when the diggers arrive," he said.
'One dimensional'
The North East Pylon Pressure Campaign (NEPPC) has said the latest review into the plan for a North-South Interconnector focused solely on "one-dimensional technical aspects of overhead lines or undergrounding".
A spokesperson for the NEPPC said that the review failed to properly analyse the overall risk-benefit of the project on the environment, the affected communities, the landscape, heritage and farming practice.
The group described the Government's statement that the report concluded the interconnector cannot be undergrounded "because it will not provide the reliability and stability that is required" as "misleading" and said the "one and only obstacle to undergrounding" the project was Eirgrid and not the technology.
"We are heading for a very confrontational stage based on a bloody mindedness of a semi-state company to have their way and ignore the people who are more than willing to work with them if they use modern technology.
"Nobody can argue that resorting to using thousands of tonnes of steel and concrete and displacing some of the best soils in the country is the way forward," it said.
Additional reporting Laura Hogan
