Reliability Outlook Released: System Ready for Summer as New, Upgraded Resources Come Online
June 19, 2025
Ontario’s electricity system is prepared for the summer and is expected to have adequate supply for the rest of 2025 as firm demand is expected to rise by a modest one per cent this year, according to the Q2 Reliability Outlook.
Recent actions have cost-effectively secured supply that will help meet reliability needs this summer and beyond. This includes:
- new battery storage procured through the Expedited Long-Term RFP as well as upgraded capacity resources procured via the Same Technology Upgrades Solicitation, which will begin connecting to the grid throughout this Outlook period;
- approximately 2,100 MW cleared through the Capacity Auction for summer 2025; and
- about 250,000 smart thermostats that are enrolled in the Save on Energy Peak Perks demand response program, which can deliver a demand reduction of about 200 MW this summer.
This will also be the first summer season following the launch of the renewed market on May 1, 2025, which introduced a Day-Ahead Market that commits resources the day before real-time through financially binding schedules, increasing operational and price certainty.
Looking ahead, the IESO expects to have sufficient reserves to meet system needs in 2026 except for one week currently projected in the latter half of the year. The IESO will work closely with market participants to co-ordinate outages during this time to mitigate reliability issues.