Annual Planning Outlook

A 20-year forecast for Ontario's electricity system, the Annual Planning Outlook (APO) includes projected electricity demand, a resource adequacy assessment, transmission considerations, and performance indicators, such as an emissions outlook, and identifies the province's energy and capacity needs. By providing timely and transparent information about future electricity needs on a regular basis, the Outlook is intended to guide investment decisions and market development.

Annual Planning Outlook - cover


All electricity users – residential, commercial, institutional, industrial and others – contribute to province-wide energy demand. Satisfying consumer demand for electricity is the IESO’s highest priority. The demand forecast serves as the basis from which Ontario’s resource needs are assessed. The forecast informs system adequacy needs by anticipating future requirements, which are affected by many factors, including consumer behaviour, demographics, the economy, energy prices, transportation policy, and energy-efficiency measures.


Overall demand growth over the next 20 years will be largely driven by modest growth in the residential, commercial and agricultural sectors, as well as the increased electrification of transportation. As a result, energy demand is expected to grow between 0.4 per cent and 1.4 per cent each year over the forecast period.

  Fig 1-ES-01 


Ontario’s diverse supply mix means the province is well positioned to meet future resource adequacy needs. The APO forecasts that Ontario is generally expected to have enough energy to supply demand over the next 20 years. Having reliable baseload facilities like nuclear and hydroelectric, along with the combined cycle gas fleet, means there should be ample energy available to meet expected needs under most circumstances.


Although Ontario’s energy requirements can largely be met with existing and available resources, a summer capacity need does arise in the 2020s. Assuming existing resources remain available, a capacity need of approximately 2,000 megawatts emerges in 2023 and grows slowly through 2040. This need is limited, occurring for a few short hours of peak demand each year, meaning future resource requirements are peaking in nature.


 Fig 18-01 

Other Considerations

A number of other factors have the potential to impact Ontario’s overall resource adequacy picture, including:

  • Nuclear refurbishments and retirements
  • Growth of distributed energy resources
  • Expiration of generation contracts
  • Policy decisions on energy-efficiency programming beyond 2020