Interference from a radio signal seriously disrupted the Republic's electricity grid, causing 326,000 customers to lose power and triggering a red alert on the system, a report from the national grid has revealed.
The Commission for Energy Regulation (CER) has decided to publish a 48-page report on the August 5th incident. A spokesman for the CER said that in future all reports on serious disruptions would be published and put on its website.
The primary cause of the disruption was a radio signal detected by the Northern Ireland power system. The signal seemed to suggest that the grids north and south had become separated, which was not correct.
In response to the spurious signal, the north-south interconnector was seriously affected. This had a knock-on effect on three ESB power stations. One part of the Moneypoint plant and one station at Tarbet, Co Kerry, completely ceased production, while another part of Moneypoint suffered a large reduction in output.
Customers started to lose power from 10.22am and some had to wait until midday to be reconnected. A report on the incident - written by ESB National Grid - said that, following the event, the detection scheme used by both power systems "has been modified to prevent a recurrence".
The report says control systems at the three plants involved will need to be reviewed, along with the testing of components. The report also suggests some operating procedures and training requirements will need to be updated.
The report does not disclose where the original radio signal which prompted the incident came from.
A spokesman for the CER said publishing the report was an important step and showed the system was operating transparently.
It was reported last week that the number of "amber alerts"warning of potential shortages in the electricity system has doubled to 50 so far this year. An "amber alert" is when the system has only approximately 400 megawatts of power in reserve, the equivalent of one large gas-fired station.
A red alert indicates an even smaller reserve. The alerts warn suppliers of power to the national grid to act with caution.
A new plant at Tynagh, Co Galway, is not expected to come into operation until about March/April.
