The underground option for the North-South Interconnector would be three times more expensive than the original project plan, the Minister for Communications, Climate Action and Environment, Denis Naughten has said.
Quoting EirGrid estimates, he said that the cost of constructing the proposed North-South Interconnector will be €286m.
Some €180m of this cost would be incurred in Ireland and the remaining €106m would be incurred in Northern Ireland, Minister Naughten said.
Due to a number of complications of putting a project of this scale underground the cost would reach somewhere in the region of €992m, he added.
Minister Naughten was responding to a number of parliamentary questions from Fianna Fail TDs.
“I am told the only feasible way to underground a circuit with 1,500 Megawatt capacity over a distance of 138km is to use a specialised high-voltage direct current (DC) with conversation equipment at either end, not AC (alternating current) technology.
“For a DC link to act reliably with a synchronous network, it would be necessary to develop new and complex control systems that have not been tried before in order to replicate the functionality of an AC interconnector.
“I am told that it is not the same as undergrounding in regard to some other projects.
The example that has been given in the past is the Aachen to Liege project, where there was undergrounding, but over a much shorter distance and with a lower capacity.
“If we take the cost of that project based on the bigger scale that is required here, the DC undergrounding cable option as applied there would cost in the region of €992m, which is significantly higher than what is projected here,” he said.
Meanwhile, Minister Naughten has agreed to meet representatives from anti-pylon groups in counties Monaghan, Cavan and Meath today.
The North-South Interconnector
Approximately 400 landowners will be affected by the development of the North/South Interconnector.
However, Minister Naughten believes the proposed interconnector is a critical piece of energy infrastructure that will benefit all the people on the island of Ireland.
The new market arrangements will be in place in 2018 and will yield benefits for electricity market customers in the North and in the south, he said.
The North-South interconnector, which will further support the single electricity market and reduce costs for consumers, has received planning permission in Ireland and is in the planning process in Northern Ireland.
“This vital project, which will ensure the security of supply in Northern Ireland, is a further example of the interdependence of our energy systems.
“It is envisaged that it will lead to initial savings of €20m/year, increasing to between €40m and €60m each year by 2030, shared between Ireland and Northern Ireland,” he said.
These cost savings will ensure there are benefits for every home and business in the State, Minister Naughten said, and that the proposed investment in this electricity infrastructure is a sound one.
Meanwhile, the Minister revealed that the costs of developing the North-South Interconnector will not be borne by the Irish Exchequer.
“The project will be funded in the same way as other electricity and gas grid investments are paid for.
“These costs are approved by the regulator and charged by EirGrid, ESB Networks and Gas Networks Ireland to energy supply companies. The energy supply companies generally include these costs in customer bills,” he said.