An Bord Pleanála has given the green light to EirGrid's plans to build a new North-South electricity interconnector.
The interconnector is due to run from Batterstown in Meath, to Turleenan in Co Tyrone.
EirGrid's proposal to construct almost 300 pylons in Meath, Cavan and Monaghan was objected to by around 200 landowners on health and environment grounds.
The decision to grant approval, with conditions, follows a 12-week oral hearing into the development earlier this year.
Residents opposed to the plan were notified this morning.
The Chief Executive of Eirgrid has welcomed the decision by An Bord Pleanála, describing the interconnector as a "critical piece of national infrastructure".
Speaking on RTÉ News at One, Fintan Slye said he recognises that there are concerns and issues among landowners and community groups. He said that Eirgrid is committed to continuing to work with them to try and address their concerns.
Mr Slye said he expects a favourable decision on planning permission for the northern element of the project in the new year. He said that it has to go due process, but Eirgrid have put forward the most appropriate solution.
An Bord Pleanála inspector Breda Gannon approved planning permission for 299 pylons but set out nine conditions for the planning.
The inspector also noted the findings of the Health Service Executive that there should be no concern about the electromagnetic fields surrounding the pylons as long as the interconnector is properly monitored and operated in line with international standards.
Giving their reaction, the North East Pylon Pressure Campaign Committee said they were bitterly disappointed that their concerns over health and the environment were not taken into consideration.
Padráig Reilly from the committee said they still believed that the high voltage lines could go underground and EirGrid would now find itself in an impossible situation trying to negotiate with up to 200 landowners who are opposed to the interconnector.
Reacting to the decision, Taoiseach Enda Kenny said that An Bord Pleanála is independent in its views.
He said: "It is a completely independent board. We have an all island energy market and these kinds of facilities are important for the economy north and south.
"But it's not for me to adjudicate on the independence of An Bord Pleanála."
Mr Kenny said he understands that it will go for a judicial review which will also be independent in its determination.