Northern Ireland’s electricity Transmission System Operator, SONI (System Operator for Northern Ireland) has published its annual Winter Outlook where it says it expects there will be sufficient generation to meet consumer demand over the winter period in normal operating conditions.
The annual Winter Outlook helps to inform the electricity industry and supports preparation for the coming months. The 2025/26 report covers the period from 3 November 2025 to 5 April 2026.
It is a point in time assessment, based on the best information available. The data freeze date for this year was 20 October 2025.
This assessment indicates the risk of any disruption to consumers due to insufficient generation being available to meet demand is small, provided the expected portfolio of generation remains available.
The Loss of Load Expectation (LOLE) in Northern Ireland for the five months of the winter period is 1.5 hours. This remains within the level of risk of 4.9 hours that is set by the Department for the Economy. LOLE is a metric used in power system reliability assessment to measure the probability and expected duration of a system’s inability to meet demand. It does not necessarily mean that electricity consumers will be without supply for any period.
2025 has been a challenging year operationally due to prolonged forced outages of Northern Ireland generators. Significant generation at Ballylumford was unavailable at the start of the year following storm damage sustained in December 2024, with the station returning to full capacity in July. Since June, the system has been without a large generator at Coolkeeragh power station following a forced extension to planned generator maintenance. Generation at Coolkeeragh power station is expected to return to full capacity in December 2025.
Despite these challenges, the System Operator has sought to reassure consumers that it still expects the risk of any disruption to the electricity supply to be low.
SONI Director of Operations, Emma Morris, explains:
“Each year, we publish an annual Winter Outlook to help support industry preparations for the winter period. This year, our assessment shows that we expect there will be sufficient generation to meet consumer demand, assuming the expected portfolio of conventional generation remains available for the remainder of the winter period.
“Operating any power system is profoundly complex, and as a System Operator, our priority is always to ensure a safe, secure and reliable supply of electricity to homes, farms, businesses and public services across Northern Ireland. We continually monitor security of supply and are working closely with industry partners and stakeholders to mitigate risks and ensure we can meet consumer demand in the months and years ahead.”