Ofgem has approved a total of five interconnection projects which it said will add between £2 to £5 a year on individual consumer electricity bills in Great Britain over the years 2030 to 2055.
The approval means the projects qualify for Ofgem’s ‘cap and floor’ regime, which provides a guarantee of how much money they will make.
It gives the developers a minimum return (floor) and a limit on the potential upside (cap) for a 25-year period.
The Scotland-Northern Ireland link, known as LirlC, is being developed by Transmission Investment.
It said the project will provide up to 700 MW of capacity between the Irish Single Electricity Market and the Great Britain wholesale electricity market.
Both projects still face further regulatory and planning hurdles but the Ofgem approval makes them likely to happen.
An existing 500 MW interconnector between Scotland and Northern Ireland has been operated by Mutual Energy since 2001.
A second 500 MW link between the Republic and Wales, known as Greenlink, is due to be operational shortly.
Keith Morrison, Project Director for LirIC, said: “Transmission Investment are pleased with Ofgem’s announcement today and its recognition of the benefits that LirIC will bring to consumers in Great Britain and Northern Ireland.
“In the coming months we anticipate more important milestones including the completion of further regulatory licencing requirements.”