The North-South electricity interconnector will leave a “terrible scar” on Co Armagh’s landscape, an Assembly member said.
A 400kv overhead line between Northern Ireland and the Republic to handle growing demand across the island has received planning approval.
Infrastructure Minister Nichola Mallon fended off criticism from local public representatives at the Assembly.
There is going to be a terrible scar across our beautiful countryside in ArmaghJustin McNulty
Her Newry and Armagh SDLP colleague Justin McNulty said: “There is going to be a terrible scar across our beautiful countryside in Armagh.
“This ugly line of unsightly pylons will be unacceptable throughout our beautiful countryside.”
The scheme has been opposed by some landowners in counties Armagh and Tyrone on the route to the southern network in Co Meath.
Its proponents said it would safeguard the country against any power generation deficit in the years ahead.
Ms Mallon declared it a vital piece of energy infrastructure.
“It is about improving our ability to maximise our renewable energy and reduce our reliance on fossil fuels and it is a strategic all-island project.”
She acknowledged local concerns.
She added: “I also recognise the strategic and economic importance of this project and also its importance in terms of tackling the climate emergency.”
She said without taking action there was a predicted energy deficit by 2025.
“It will have a huge impact in people’s own homes.”
She added: “It means they will have a secure supply of energy for their homes and businesses.”