Moyle Interconnector


Moyle Interconnector has experienced a number of faults on its low voltage cables since 2010, with the result that Moyle has only been able to operate reliably at half capacity since June 2012. It has been agreed with the Utility Regulator that the solution to repair the cable and return it to full capacity is to replace the low voltage parts of the Moyle cables, and this project is making good progress with the procurement process nearing completion.

Moyle will continue to operate at half capacity until the new cables are commissioned. The expected delivery date for this project is 2017 but Mutual Energy will do all it can to achieve completion sooner, if possible. Early delivery is very much in the interests of Northern Ireland energy consumers as the Moyle interconnector, restored to full capacity, can make a major contribution to Northern Ireland’s generation capacity margin.

In the interim, Mutual had been examining a range of possible options for effecting a temporary solution including an in situ seabed repair to the existing low voltage cable fault. While this engineering process did yield some positive results, it has ultimately not produced a satisfactory outcome and a decision has been made, as of November 2014, to discontinue this work and focus fully on the long term repair project replacing the low voltage cable parts, which provides a permanent solution.

In addition to the replacement cables project, MEL has already engineered a back-up option, so that if necessary in the interim, the cables can be reconfigured to continue to deliver 50 per cent capacity in the event of a fault on the other low voltage cable.


The Moyle Interconnector links the electricity grids of Northern Ireland and Scotland through submarine cables running between converter stations at Ballycronan More in Islandmagee, County Antrim and Auchencrosh in Ayrshire. The link has a capacity of 500MW.

The commissioning of the Moyle Interconnector marked a real watershed for the electricity consumers and economy of Northern Ireland. When it went into commercial operation in early 2002, it ended the isolation of Northern Ireland from the much larger electricity systems and markets of Great Britain and the European mainland, where interconnection of national electricity systems had been the norm for many years. It has made a major contribution to the drive for lower electricity prices in Northern Ireland, which has a history of high energy costs.

The Moyle Interconnector has enhanced the security of electricity supply throughout Ireland and reduced the costs of running the electricity system. It now provides competition in the electricity market arrangements in Ireland and makes possible trading with our neighbouring market in Great Britain. The Moyle Interconnector transmission capacity is available for third party access, i.e. to anybody who wants to trade in electricity in either direction between Ireland and Great Britain or beyond.

The Single Electricity Market (SEM) for the island of Ireland went live on 1st November 2007. The current electricity market in Great Britain – the British Electricity Trading and Transmission Arrangements (BETTA) came into effect in April 2005. The Electricity market on the island of Ireland is scheduled for significant change in 2016 as it is adapted to the European Target Model which aims to deliver an integrated internal electricity market. The Moyle Interconnector provides a vital link for trade between the electricity markets of Ireland and the rest of Europe.

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