Grid Alerts Explained

EirGrid is responsible for the safe and secure operation of Ireland’s electricity system. We manage the supply of electricity in real time, whether from electricity generators on the island of Ireland, or from international suppliers. Ireland’s energy demands are monitored by EirGrid’s National Control Centre which carefully balances supply and demand on a minute-by-minute basis. This involves the movement of large volumes of electricity around the island of Ireland, where it is then supplied to large energy users, and to homes and businesses via ESB Networks.

An alert is not an unusual event. When the buffer between electricity supply and demand is tighter than EirGrid would like, EirGrid issues an alert to the electricity sector. Alerts are more likely to take place in the winter months when demand for electricity is at its highest. A System Alert (previously known as an Amber Alert) is the lowest level alert, followed by System Emergency (previously known as a Red Alert).

When EirGrid issues a System Alert (previously an Amber Alert) there is no immediate impact for users of electricity. Instead, a System Alert warns of the potential for temporary electricity supply issues in the near future, so that our expert engineers and those in the wider electricity sector can take pre-planned actions to protect the integrity of the grid. It is a signal for all generators of electricity to make their facility available for use and not to put their facility at any risk of tripping. A System Alert often passes off without incident once a sufficient buffer between electricity supply and demand is restored.

A System Emergency State (previously a Red Alert) is much less frequent than a System Alert. It is issued by EirGrid when there is a high risk that not all electricity demand can be met. When the power system is in this state, EirGrid engineers will work closely with ESB engineers to take pre-planned actions to protect the integrity of the grid. These actions may include implementing controlled outages or a temporarily reduction in electricity supply for some users. A System Emergency is lifted once a balance between electricity supply and demand is restored.

To protect the integrity of the power system and prevent a more serious event, controlled outages may have to be implemented by EirGrid and our partners ESB Networks. Large non-domestic energy users may see their electricity supply temporarily curtailed and some domestic customers may experience temporary controlled outages. By doing this we remain in control of the grid and avoid the risk of extensive unplanned interruptions of electricity supply. In such situations EirGrid and ESB Networks will work to make controlled outages as short-lived as possible, and will rotate the locations that are impacted by them. If you think you are experiencing a controlled outage, please visit powercheck.ie for up-to-date information.

Controlled outages are a measure of last resort, put into operation when circumstances require our specialist engineers to take action to protect the integrity of the power system during a system Emergency State. In this scenario, deliberate measures are taken to interrupt power supply to a portion of electricity users, for a period of time, to reduce demand when the supply of electricity is inadequate. Plans, approved by the Regulator, are in place to undertake such controlled outages, while protecting the supply of electricity to identified critical infrastructure.

A blackout occurs when there are electricity outages across a widespread area in an uncontrolled manner. One of the reasons controlled outages are put into operation is to avoid widespread blackouts. Plans, approved by the Regulator, are in place to undertake the restoration of supply to customers after a system Blackout State.

 

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 some planned generators by developers; decreased availability of existing generators as they age, and; the need for essential maintenance on other generators. This maintenance work was considerably delayed due to complications arising from Covid-19 restrictions, which prevented specialist engineers from travelling to Ireland.

EirGrid studies suggest that there is an increased risk of alerts this winter. EirGrid has thoroughly planned for grid alerts, and is working with the regulators, Government, ESB Networks, SONI, the National Grid UK and large energy users, to reduce the potential impact for all electricity users. The good news is that two large electricity generators (Huntstown and Whitegate) have been returned to service after extended forced outages. EirGrid is continuing to closely monitor the situation. Working with others in the industry, we are managing Ireland’s electricity supply and minimising risk to the electricity system wherever possible.