The new north-south electricity interconnector is to be built entirely above ground, the Belfast Telegraph can reveal.
After years of delays, enquiries and protests, a planning application for the controversial £250m project will be submitted today by Irish power giant EirGrid, which owns the grid south of the border.
Its proposal is for massive pylons to be erected between substations at Turleenan, near Moy in Co Tyrone, and Batterstown, Co Meath - 85 miles away.
In a statement, EirGrid, which will be working in conjunction with NIE on the project, confirmed it will submit a planning application on the 400,000 volt 'North-South interconnection' directly to An Bord Pleanála, the Irish Planning Board, today, and that the proposal is for 'overhead transmission lines'.
It added that a 10-week public consultation on the proposals will begin on June 16.
The lodging of the planning application will infuriate environmentalists who have fought to have the massive project forced underground, but EirGrid has persistently argued that linking Ireland's northern and southern grids that way isn't financially feasible.
When first mooted in 2009, the project was to be finished by 2017, but it's now unlikely to be ready until 2020 at the earliest.
Green Party leader, Steven Agnew said an above ground interconnector was a "necessary scenario". "If we only explored the underground option, the potential is that this wouldn't happen at all," he said.
"We have to face the realities of our energy infrastructure. The need for pylons will upset people in some areas, but it's a more positive alternative to massive concrete power stations that we see at Ballylumford and Kilroot."
Brendan Smith, the Fianna Fail TD for Cavan-Monaghan, said it was "extremely disappointing" that EirGrid has no plans to place any of the power lines underground.
"They want an overhead line, which will run through Cavan, Monaghan, Meath, Armagh and Tyrone. Residents are naturally angry that this option is the only one which has been submitted," he said.
Two months ago, EirGrid Chief Executive Fintan Slye told the Oireachtas Communications Committee that the undergrounding of the North-South interconnector was "technically feasible", but the company's subsequent planning application has no provision for any underground cables.
"I am calling on Alex White (the Republic's Minister for Communications, Energy and Natural Resources) to immediately clarify the Government's position on the North-South Interconnector and to direct EirGrid to bring forward options to underground the project," said Mr Smith
"There also needs to be an immediate review of the regulations governing the construction of overhead power lines," he added.
In 2009, it was estimated that undergrounding the cables would cost more than 20 times the amount to keep these transmission lines above ground, but Mr Smith insists the cost argument has been "totally diminished".
"It is now widely accepted that the costs in laying the cables underground is substantially reduced to under two times the cost of over-grounding," he said
"The (Irish) Government needs to look at this issue again. It is not acceptable for the Government to ignore facts as they change on the ground and plough on regardless."
When finally built, the interconnector will be Ireland's second largest, joining a predecessor between Tandragee and Louth.
NIE has estimated there is a cost of £20m to £30m for every year the project is stalled - and hopes that Northern Ireland will meet its ambitious target (40% of its energy to come from renewable sources by 2020) are fading.
Businesses, especially those involved in renewable energy, have been pushing for an interconnector because the northern grid is often overloaded.
And, at present, cross-border electricity suppliers are not able to share electricity at peak times in the volumes they would like.
When the interconnector is up and running, cheaper surplus energy generated on one side of the border can be shared by customers on the other side.