Resource Eligibility

After years of having surplus electricity supply, Ontario is entering a period of need. This is primarily being driven by economic growth, retirements and refurbishments of power plants and increased electrification of the transportation and manufacturing sectors. To meet these growing needs, Ontario requires an additional 4,000 MW of electricity supply between 2025 and 2027, which is the equivalent of adding a city the size of Toronto to the electricity grid.

The IESO recommends pursuing a diverse portfolio of supply options. The procurement will target new capacity from a variety of resources including approximately 2,500 MW of storage, contributions from other non-emitting resources such as hybrids and biofuel resources, and up to 1,500 MW of natural gas. These investments could create one of the largest battery storage fleets in North America, while providing assurance that Ontario’s electricity system will continue to be reliable and affordable as it transitions to a decarbonized future.

Resource Eligibility Interim Report cover page

Included in this report:

  • An overview of Ontario’s emerging electricity needs from 2025 to 2027
  • A summary of Ontario’s Long-Term 1 procurements
  • An evaluation of the risks associated with procuring new energy supply, with emphasis on the unique risks associated with storage
  • An explanation of the role natural gas can play as a transitional fuel

Read the full report

Report Highlights:

  • To maintain electricity system reliability, the IESO recommends that Ontario procure approximately 2,500 MW of storage, contributions from other non-emitting resources such as hybrids and biofuel, and up to 1,500 MW of additional natural gas generation.
  • Storage offers promise for Ontario’s electricity system, but is faced with a number of reliability risks, including potential project delays, supply chain disruptions, grid integration challenges and operational limitations.
  • Natural gas provides Ontario’s electricity system with flexibility, reliability and security as other non-emitting forms of electricity supply are developed.