PUTTING the cables for the proposed north-south electricity interconnector underground would cost £1 billion, the head of the utility regulator has warned.
Jenny Pyper said any notion that undergrounding the proposed line between Ireland's two electricity grids was viable was a "myth".
The System Operator for Northern Ireland (Soni) and EirGrid - which operate the grids - seek to build an 85-mile overhead line to link the two systems.
However the plans have faced opposition from people living in the areas of Tyrone, Armagh, Monaghan, Cavan and Meath affected.
They say it would be an eyesore while some claim it would have an adverse affect on health.
The whole project will cost at least £204 million - but the Utility Regulator chief executive Jenny Pyper said to underground the cables would cost many times more.
And speaking at the EirGrid Group conference in Belfast yesterday, she warned consumers would "pay dearly" if the cables are not in place by 2019.
Plans were first submitted to authorities in 2009 by NIE, but Soni took over as applicant last year.
A public inquiry into the proposals opened in 2012 but was adjourned and is not due to start again until next year.
Ms Pyper said that "anyone interested in keeping the lights on and ensuring prices are low understands the risks and works to make it happen".
“What is clear is that the option of undergrounding the interconnector would not only jeopardise the expected delivery date of 2019 but it simply could not be delivered by 2021 when our electricity capacity margin becomes critical," she said.
“It would also create additional technical challenges, and it will be extremely costly to construct - up to five times more expensive than the overhead interconnector proposals. So it would be impossible to deliver any alternative undergrounded route in time to meet our generation shortfall.
"So the myth of an undergrounded interconnector as a Plan B is just that – a myth.
“We need to make a choice. Do consumers and businesses want the lights to stay on and as cheaply as possible? If so, the interconnector that is in planning is the only option.”
Soni's general manager Robin McCormick said the regulator's comments were welcome and he agreed "that politicians, business and the community need to grasp the critical need for the interconnector if Northern Ireland’s lights are to stay on”.
