Energy grid sounded alerts twice last year

ESB crews on a callout in Letterfrack, Connemara, during Storm Éowyn in January. Picture: Eamonn Farrell/ RollingNews.ie

Ireland’s energy grid sounded alerts twice last year, with five further warnings that supply was within margins that were considered “not optimal”.

System alerts, which were previously known as amber alerts, are issued by grid provider EirGrid when the buffer between electricity supply and demand is “tighter than optimum”.

EirGrid says an alert is “not an unusual event” and occurs “when the buffer between electricity supply and demand is tighter than EirGrid would like”. A system alert is the lowest-level alert, followed by system emergency, previously known as a red alert.

The alerts serve as a warning to the wider electricity sector to take action to protect the integrity of the grid and avoid entering system emergency when there is a risk that not all electricity demand can be met.

According to a parliamentary response by energy minister Darragh O’Brien to Tipperary Independent Mattie McGrath, there were two alerts on the system in the last year, both coinciding with large storms.

“I am advised that there have been two system alerts issued in the last 12 months. These alerts took place during Storm Darragh in December 2024 and Storm Éowyn in January 2025,” Mr O’Brien’s response said.

Storm damage

Unprecedented damage was caused to the electricity network during Storm Éowyn, leaving some 768,000 customers without electricity. Mr O’Brien said there had been “margin warnings” throughout the year too.

“I am further advised that there have also been five system margin warnings, which is a pre-alert state and means the TEG units are being calculated in the reserve for the system. The TEG units have helped to reduce the number of system alerts and provided a buffer to the electricity system over the last year.” 

TEG units are used to remove water vapour from natural gas before transportation for pipelines.

While there were no alerts towards the end of the last decade, EirGrid said they have increased due to a number of factors: “Increasing electricity demand and tightening margins around electricity supply means we are having more system alerts. Pressure on supply has been heightened by increased electricity demand; a delay in new generators coming onto the grid; the withdrawal of planned generators by developers; decreased availability of existing generators as they age; and the need for maintenance on other generators.” 

Central Statistics Office data released in July 2024 showed a 20% increase in data centre energy consumption between 2022 and 2023, accounting for 21% of total electricity consumption. Mr O’Brien said this growth in data centre “energy consumption was anticipated”.

Tánaiste Simon Harris last month told Cabinet large energy users would be at risk in the event of an attack on Ireland’s grid. Mr Harris chaired a meeting of the Government’s taskforce on emergency planning, which discussed Ireland’s ability to deal with a potential attack on our energy supply. 

The taskforce considered lessons from ‘Exercise Cathal’, which ‘war-gamed’ a scenario in which Ireland’s gas pipelines were damaged. The meeting was told that there are a number of large gas users in the state that would be particularly at risk from an attack on our gas supply.