A SUBSEA power line between Scotland and Northern Ireland has been given the green light.

It is one of several cables approved by energy regulator Ofgem, which it said will carry enough electricity combined to power millions of homes.

In total, there are five lines which have been approved. This includes three interconnector cables – one linking East Anglia in England to Niederlangen in Germany, one running between Bodelwyddan in north Wales and Ireland, and another between Scotland and Northern Ireland.

The Scottish line will run between Hunterston in Ayrshire to Kilroot in Northern Ireland. It is set to be approximately 142 kilometres in length and will deliver 0.7 gigawatts (GW) of additional electricity capacity.

Two other lines – known as offshore hybrid assets – were also approved and will connect the England to Dutch and Belgian grids with offshore wind farms belonging to the European countries in between.

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Interconnectors are intended to provide more flexibility over energy supply, either by exporting surplus power abroad or buying it from other countries to meet its own demand.

Britain currently has interconnectors that can carry about 11.7GW of electricity and the new interconnectors will increase that to 12GW in 2030 and 18GW in 2032.

One gigawatt hour of electricity is enough to power about one million homes for one hour, Ofgem said.

The regulator initially refused the interconnectors because they are set to add between £2 and £5 a year to energy bills from 2030 to 2035.

Akshay Kaul, Ofgem director general for infrastructure, said the regulator had only approved projects “which deliver for consumers in terms of value, viability and energy security”.

He said: “As we shift to a clean power system more reliant on intermittent wind and solar energy these new connections will help harness the vast potential of the North Sea and play a key role in making our energy supply cheaper and less reliant on volatile foreign gas markets and associated price spikes.”

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He added: “With Britain expected to become a net energy exporter in the 2030s, these connections will equip us with world leading technology to export more of our surplus clean power overseas.

“They will also provide greater access to energy imports, which together with domestic low carbon energy sources such as nuclear and biomass, will provide vital back-up energy sources when renewable generation is more limited here.”

How many subsea electricity cables are there in Scotland?

In Scotland, subsea cables are often used to link the Scottish mainland to the islands, to provide bulk transport of power between areas of power generation and centres of demand, and to provide a connection between offshore generation sites to a landfall site.

According to the latest statistics from the Scottish Government, there are around 976km of subsea power cables in Scottish seas, with recent cables including between Kintyre and Hunterston and Caithness and Moray.

Marine Scotland, the Scottish Government agency responsible for managing Scotland’s seas, said the length of subsea power cables doubled between 2015 and 2019 as a result of an increase in the number of offshore marine renewable energy schemes.

The area with the most power cables is the Clyde, at 255km. The Orkney Islands have around 123km, while Argyll has 88km.

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According to 2020 figures from the UK Government, Scotland provides around a quarter of the UK’s overall renewable output.

We told how Scotland has generated more renewable energy so far this year than in any other.

The Scottish Government has been contacted for comment.