IESO Reliability Outlook - Modest Demand Forecasted Over 2027
September 18, 2026
Ontario’s electricity grid is expected to be reliable to meet the needs of businesses and communities for the next 18 months, according to the IESO’s latest Reliability Outlook.
This Outlook reflects the ongoing impact of trade uncertainty on the Canadian and Ontario economies. Evidence of these impacts is reflected in the demand forecast, which projects moderated electricity demand growth in 2026 and into 2027. While economic uncertainty is expected to affect demand through most of 2027, growth is forecast to accelerate later in the year as large loads, including data centres, are added to the system.
For this Reliability Outlook period, which includes Pickering Nuclear Generating Station’s “B” units going offline for refurbishment and a scheduled vacuum building outage at Darlington Nuclear Generating Station in spring 2027, Ontario’s electricity system is expected to remain mostly adequate owing to additional new generation projects coming online and co-ordinated management of planned outages.
Generators are advised not to schedule outages during periods when reserves are forecast to be low and are strongly encouraged to plan and co-ordinate the timing of outages with IESO staff.
For the full Reliability Outlook, visit the IESO's website.