SONI signals cautious optimism through Winter Outlook

Monday 16 October 2023

SONI forecasts that despite risk of tighter electricity buffer margins there will be sufficient electricity generation this Winter to meet expected demand in normal operating conditions

SONI, the electricity transmission system operator for Northern Ireland, has today published its Winter Outlook which sets out expectations for Northern Ireland’s electricity supply and demand across the 2023/24 Winter period.

The publication, which is based on detailed research and analysis by SONI’s engineers, shows that there is expected to be sufficient electricity supply to meet demand this Winter in normal operating conditions.

The report indicates that the buffer margins for electricity generation may be tighter than normal at times, and that we may be more reliant on the availability of imports and renewable generation.  

The Loss of Load Expectation (LOLE) in Northern Ireland for the five months of the Winter period has increased from 1.5 hours last Winter to 1.95 hours. This remains within the level of risk of 4.9 hours that is set by the Department for the Economy.

This means that there is a risk that the system could enter the Alert State at times, most likely at periods of low wind and low interconnector imports but the risk of the system entering the Emergency State due to insufficient generation being available to meet the demand is low. A System Alert has no immediate impact for users of electricity.

Managing Director of SONI, Alan Campbell explains:

At SONI, we plan and operate the Northern Ireland Electricity Transmission System, or the electricity ‘Grid’ as it is better known, 365 days a year. Due to their complex nature, there are challenges in managing all electricity systems and Northern Ireland is no different. Our expert engineers are highly trained to manage the risks associated with balancing supply and demand, ensuring electricity gets from where it is generated to where it is needed.

“Every year, we publish our Winter Outlook to help the industry, businesses and consumers across Northern Ireland prepare for the months ahead. Typically, due to our climate, we see demand increase at ‘peak times’ during the colder weather and darker nights and there is always some risk of potential disruption to electricity supply.

Mr Campbell continues: “It is important to be clear that whilst there is a small increase in risk this year due to tightening of electricity buffer margins, we do expect that there will be sufficient electricity generation to meet demand in normal operating conditions. Whilst a reduction in conventional generation capacity could pose a challenge, we are well placed to manage this risk.

“We are cautiously optimistic about the outlook as our detailed analysis shows that we have sufficient generation to meet demand this winter. SONI has robust contingency plans in place to manage the challenges that may arise as a result of tight generation margins including importing from Great Britain and Ireland, utilising Open Cycle Gas Turbines and batteries and accelerating the onboarding of new, cleaner conventional generation.”

For more information, visit



The full Winter Outlook 2023/24 can be accessed here.

About SONI

SONI (System Operator for Northern Ireland) is the Electricity Transmission System Operator for Northern Ireland. We manage the transmission system, or the ‘Grid’ as it is better known, to bring electricity to every part of Northern Ireland.

From our control centre in Belfast, we match supply and demand for power every second, ensuring a safe and reliable power system. In addition to managing the Grid in real time, our expert engineers are responsible for planning ahead to ensure our energy infrastructure meets the needs of the future.

SONI does not generate electricity, deliver demand response, or control market flows on interconnectors. As a transmission system operator, we plan and manage the electricity grid with the generation that is made available to us by the providers who secure contracts through the all-island capacity market for electricity. We rely on others to have this power available to us when it is needed.

We are working to upgrade our power system to help deliver Northern Ireland’s Energy Strategy and facilitate a cleaner energy future.

About System Alerts

A System Alert has no immediate impact for users of electricity. It is designed to alert the industry that there is the potential for temporary electricity supply issues in the near future, so that SONI’s 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 take any action that increases risk of tripping.

A System Alert often passes off without incident once a sufficient buffer between electricity supply and demand is restored. More information can be found here: