Breakdowns at two ESB power plants

Units at two ESB power plants broke down yesterday on a day when peak demand for electricity hit a record high.

Last night the State-owned company said despite problems with the units it had sufficient spare capacity to avoid any power shortages.

Demand for electricity reached 5,042 megawatts yesterday evening. The grid company, EirGrid, confirmed this was the highest level of peak demand to date, although the company said it had managed to cope with the peak successfully and the system was being managed diligently.

Stations at Tarbert, Co Kerry, and North Wall in Dublin both had to take units out of commission. The two units were producing 160 megawatts of power between them. The unit at Tarbert was out of commission for only a brief time, said the ESB, although the other unit at North Wall remained out of commission last night.

The peak demand on the day came at about 5.30pm and an ESB spokesman said at that point the company had 250 megawatts of spare capacity. Some sources suggested the system came close to a very "critical" situation that was only narrowly avoided, but the ESB and EirGrid denied this last night.

This week EirGrid, which operates the national electricity transmission system, denied suggestions that consumers could be facing blackouts during the Christmas season. Despite the tightness in supply and technical problems with some ESB plants, the grid company was reiterating this point last night.

It is understood there have been 21 "amber alerts" this year. Amber alerts inform generators to behave cautiously because supply and demand are tight.

Earlier this week the ESRI, the economic think-tank, issued a report outlining concerns over the power system.

It said: "In Ireland electricity demand is at its peak in the winter months, when the days are short and the weather is cold. This causes the likelihood of electricity shortages to peak at the same time. We define a shortage as any instance where demand for electricity is larger than supply".

The report said that at the end of November 2006, 18 per cent of all generation capacity was unavailable because of forced repairs or "outages". The report was broadly upbeat about blackouts happening based on the main figures but it warned that the non-availability of so many plants changed the calculations somewhat.

"Unfortunately, not all power plants are fully operational. Ireland's generation plant portfolio is older than average, which leads to one of the lowest average availability rates in Europe," the ESRI report found. It said one of these plants - at Poolbeg - was often in maintenance and it was meant to provide 3.5 per cent of total national capacity.

The Republic is increasingly relying on imported power from Northern Ireland. There is an electricity interconnector between the North and the Republic.