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John Simpson

Some reading of interest in SONI's draft plan for Northern Ireland electricity grid

John Simpson


Northern Ireland's electricity grid is in need of enhancement with a shrinking capacity margin on the horizon

Northern Ireland's electricity grid is in need of enhancement with a shrinking capacity margin on the horizon

Northern Ireland's electricity grid is in need of enhancement with a shrinking capacity margin on the horizon

SONI, the system operator for electricity in Northern Ireland, has drafted proposals for the strengthening and enhancing of the NI electricity grid.

The draft, an updated 10-year plan for the years to 2028, is expected to ask the Utility Regulator to approve capital investment costing £465m, equivalent to over £45m each year.

Energy users now have the opportunity to comment on the draft SONI plan. Is it ambitious enough to underpin the needs of the NI economy? Can customers afford to pay for it?

The details of 81 projects included in the draft plan by SONI have been published by the regulator as a step in building approval for a comprehensive plan.

This development plan comes at a critical juncture: the all-island integrated single electricity market is evolving from the structural changes introduced two years ago, but now continuing to function on an all-island basis after the UK has left the EU, with a special protocol which allows the all-island SEM to remain as an agreed UK-EU arrangement.

The amended NI electricity investment plan builds on a recent All-Island Electricity Capacity Statement showing that, north and south, the amount of spare electricity generating capacity has been reducing to the point where new investment and changed transmission systems are needed if the grid, for the whole island, is to be sustainable for the longer term.

A capacity deficit of over 220mw is expected in the Republic of Ireland by 2024.

By 2025, in Northern Ireland the capacity margin could be as low as 50mw - well below any recent year.

The Northern Ireland capacity estimate assumes that by 2025, the Kilroot coal-burning power plant will have closed.

The draft SONI plan envisages a series of upgrades and new developments which would make the all-island grid ready for a modest increase in electricity demand.

Critically, the draft SONI plan presents four major capital investment projects. These are:

• a high-capacity 400kv interconnector from Tyrone to Cavan (long awaited);

• major re-enforcement of the grid from Magherafelt to Coolkeeragh;

• major re-enforcement of the grid from Ballylumford to Castlereagh; and

• an underground connection from a large 480mw Belfast power station to Castlereagh.

While there is a growing appreciation that the major cross-border interconnector is overdue and could be a source of all-island financial savings, the draft plan expects the project to be operational by 2023.

Recent NI developments would suggest that timing looks optimistic.

The high-capacity north-south interconnector already has full planning permission on the southern side of the border but still awaits final approval from the Executive Minister for Infrastructure, Nichola Mallon.

In a further cross-border link, a connection from Turleenan in Co Tyrone to Dromore in Co Donegal is planned to enhance electricity supplies into Donegal.

SONI has made some changes to the development plan which is now to be updated.

Two potentially large projects, listed last year, have been removed from the proposed new investment plan.

Several years ago, investors assessed the merits of a compressed air energy storage scheme, to generate electricity to add to capacity when the system was operating with high demand (with higher sales prices) and to store compressed air in underground caverns when load on the grid was low and this would be comparatively cheap.

The SONI draft plan notes that this project has been cancelled.

A second potentially large project is also removed from the plan. There was in recent years a serious commercial interest in harnessing the tidal energy around the north coast of Co Antrim.

The possible application for a grid connection to undersea turbines at Fair Head and Torr Head has disappeared because the application has been withdrawn.

For the immediate future, there seems to be no expectation of any coastal energy generation facilities. Earlier investigations in Strangford Lough or off the south Down coast have left no declared proposals.

Nevertheless, the SONI draft plan points to compelling developments if the electricity grid is to function successfully.

Belfast Telegraph