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Press Release - 13th May 2013

Decision on long-term repair of Moyle Interconnector cables


Mutual Energy Limited (MEL), owners and operators of the Moyle electricity interconnector between Northern Ireland and Scotland welcomes the news that the Utility Regulator has today confirmed its support for MELís approach in relation to the long-term repair of the Moyle Interconnector cables. Since September 2010 Moyle has experienced four cable faults, three of which have been repaired and the fourth has just this week been precisely located and identified. As a result, Moyle is currently operating at 250 megawatt of its 500 megawatt capacity.

The faults have occurred in a specific part of the cables associated with the return conductor element. MELís primary focus has therefore been to remove the reliance on that part of the cable and the feasibility of a number of alternative long term solutions has been considered. The best solution is to lay new low voltage submarine cables along a similar route to augment the existing cables and replace the existing return conductor.

This project could be expected to take 4-5 years and could cost in the region of £60 million, although at this stage this figure is highly uncertain. It is, however, clear that the financial benefits of Moyle to the customer would far outweigh the cost of the cable replacement programme. As in all its activities, MEL, as a mutual company, will seek to keep the cost to the consumer as low as possible.

MEL recognises the tight capacity margin on the Northern Ireland electricity system, particularly from 2015 onwards so, in order to condense the project programme and restore the valuable interconnector benefits to customers, the company is proposing to run the consents process and cable procurement process in parallel. Appointment of consultants to specify and tender the new low voltage cables is expected to take place in coming days. It may be possible, with favourable conditions, to achieve an autumn 2016 commissioning date, although a more prudent base case would be autumn 2017. This programme should become much more certain by the end of 2013.

Whilst this process is ongoing, steps have also been taken to mitigate the risk to the system of a further fault on the currently in service cable. This has involved the successful design, installation and testing of a conductor reconfiguration which allows the interconnector to run at 250 megawatt without the need to rely on the incident prone elements of the cables. This reconfiguration, which can be set up in a matter of hours, effectively assures 250 megawatts of Moyle capacity.

MEL is also progressing feasibility studies on two possible interim solutions to return to the full 500 megawatt capacity ahead of installation of the new low voltage cables. These interim solutions are unconventional and may not be feasible and critically, they would rely on the integrity of the incident prone return conductor insulation. However, if feasible they would bring valuable additional capacity to the Northern Ireland system and MEL believes it is well worth pursuing these options further.

MELís decisions with respect to the long term future of the Moyle cables impact on customers in terms of both quality and cost of electricity supplies. The company is therefore keen to ensure its decisions and plans are fully transparent and so welcomes todayís confirmation that the Utility Regulator is supportive of its approach.

Notes: 1. For further details refer to letters published today (13th May 2013) on the Utility Regulator website between Shane Lynch, Chief Executive, Utility Regulator and Paddy Larkin, Chief Executive, Mutual Energy Limited:

For further information contact:

Sandra Bolan, Lagan Consulting Tel: 028 9261 9951 Email: