The ESB power station in Derry has broken down, forcing authorities in Northern Ireland to import extra power from the Republic to deal with potential shortages.
The ESB confirmed yesterday that the 400 megawatt gas-fired plant at Coolkeeragh has been out of service since December 16th. A spokesman said the company expected it to return to service some time in the middle of this month.
The plant started generating in March 2005 but has been struggling to make a profit.
It is understood a shaft at the plant has broken and a replacement is on order. It is believed the breakdown has forced the Northern Ireland electricity grid to import additional power from the Republic to help out customers of the Coolkeeragh plant and to deal generally with the loss of the 400 megawatts from the system.
At peak periods in Northern Ireland, all stations have been asked to go on full production, while additional power has also been called upon via the Moyle interconnector with Scotland.
The Republic's grid company has also been forced to take additional deliveries of power from the Moyle interconnector to keep its system stable. A spokesman for ESB National Grid said last night: "Supply is tighter than normal this winter and we routinely use all resources available to us, including, from time to time, the Moyle interconnector."
Traditionally, power is exported into the Republic from Northern Ireland rather than in the other direction. But the recent problems at Coolkeeragh have altered this.
The Derry plant has struggled to make a profit because of the high price of gas on international markets.
However, a decision on tariffs in Northern Ireland due within the next few days may alleviate the pressure on the plant.
The Coolkeeragh plant has attracted criticism from some participants in the Northern Ireland electricity industry. The regulator of the market there, Douglas McIldoon, has said "it's not the best plant for Northern Ireland". He claims the station would suit Northern Ireland better if it operated in a decentralised and separated way.
"If the Coolkeeragh plant breaks down you lose everything and that's a very large part of generation in Northern Ireland," he said recently.
For its part, the ESB has complained about the way the market operates in Northern Ireland. It claims there is not enough separation between Northern Ireland Electricity (NIE), a subsidiary of Viridian, and the system operator SONI.
The high cost of gas has led to speculation the ESB might mothball the plant for a time, but this has been strenuously denied. The ESB maintains the plant, while potentially loss-making initially, will pay for itself in the long term. The price review due shortly could have an impact on this.
When it opened last year a spokesman said: "The remuneration for the investment we've made is through our customer pricing, so we wouldn't be prepared to run at a loss for an indefinite period."
The ESB now has a range of investments outside the Republic. This is part of its strategy of offsetting market share losses in Ireland with foreign assets.