IESO Publishes 2026 Annual Planning Outlook

On March 20, 2026, the Independent Electricity System Operator (IESO) released the 2026 Annual Planning Outlook (APO), updating its long-term assessment of Ontario’s electricity system needs over the 2027–2050 planning horizon. While the 2026 APO continues to reinforce that Ontario is entering a sustained period of structural electricity demand growth, it reflects a notable recalibration of both the demand forecast and the planning framework used to manage uncertainty.

As disclosed in November 2025, the most visible change is a moderation in the province’s reference demand trajectory. The IESO now forecasts approximately 65 per cent growth in net annual electricity demand by 2050, compared to 75 per cent in last year’s outlook. This revision does not represent a reversal of electrification trends, but rather a more cautious assessment of near- and medium-term economic conditions, revised electric vehicle (EV) adoption assumptions, and a materially expanded role for electricity demand-side management (eDSM).

At the same time, the 2026 APO introduces a more explicit scenario-based planning framework, including distinct high- and low-demand scenarios that bracket a much wider range of potential outcomes. Under these scenarios, demand growth by 2050 ranges from approximately 38 per cent in the low-demand case to as much as 92 per cent in the high-demand case. Compared to the 2025 APO, which largely emphasized a single reference trajectory, the 2026 APO places greater weight on uncertainty itself as a feature of system planning.

Despite the downward revision to the reference case, the APO makes clear that Ontario’s electricity system must still prepare for very substantial incremental energy and capacity needs, particularly beginning in the early 2030s. While recent procurements and re-contracting activity have improved near-term adequacy, the IESO emphasizes that sustained investment in supply, transmission, and system flexibility remains essential if reliability and affordability are to be maintained.

Click here to read our analysis and understand what's changing, why it matters, and what it means for Ontario's energy landscape through 2050.