IESO Reliability Outlook: Cost Effective Supply Keeps Ontario's Electricity System Prepared Through March 2027
September 18, 2025
Ontario’s electricity grid is prepared for the next 18 months, with sufficient supply expected to be available to meet the needs of residents, businesses and communities, according to IESO’s latest Reliability Outlook (RO). While long-term growth is expected to remain strong as numerous large loads are planned to come online over the coming decades, this RO reflects lower demand projections compared with previous forecasts due to slower projected economic growth because of on-going trade disruptions. Electricity demand is projected to grow modestly, with firm demand expected to rise by 2.1 per cent in 2025 and 2.2 per cent in 2026.
For this RO period, Ontario’s electricity system is expected to remain adequate thanks to new battery storage projects procured through the Expedited Long-Term Request for Proposals (RFP) and possibly even the first Long-Term RFP beginning commercial operations; resources secured via the 2024 Capacity Auction for the 2025-26 winter obligation period; upgraded capacity resources procured via the Same Technology Upgrades Solicitation coming online; and second Medium-Term RFP resources, for which a maximum of about 260 MW of re-contracted resources under the capacity stream and more than 200 MW of re-contracted resources under the energy stream are scheduled to continue contributing to the grid as of May 1, 2026.