Independent Electricity System Operator (IESO)

The IESO in its procurement of seven new battery storage projects and two new natural gas-fired generators


Independent Electricity System Operator





Date Closed


Renewable Energy

Lead Office



After more than a decade of strong supply, Ontario is entering a period of emerging electricity system needs, including decarbonization. Recognizing the necessity to address these needs in a timely, cost-effective and flexible manner, the Independent Electricity System Operator (the IESO) engaged with stakeholders in the development of a Resource Adequacy Framework. On December 6, 2022 the IESO published procurement documents for the procurement of expedited long-term electricity reliability services (the “E-LT1 RFP”).  On May 16, 2023 , the IESO announced that it will be awarding contracts under the E-LT1 RFP to two new natural-gas fired generating facilities at existing locations within Ontario representing 295 MW of additional capacity and to seven new battery storage projects throughout Ontario, varying in size from 5 MW to 300 MW, collectively providing 739 MW of capacity. This is the largest utility-scale battery storage procurement in North America to date and it will prioritize Indigenous partnerships and environmental benefits. These projects complement the recent IESO agreement for the 250 MW Oneida Energy Storage Facility and concludes the first of two stages within the E-LT1 RFP procurement.

The IESO is responsible for operating the electricity market and directing the operation of the bulk electrical system in Ontario.

Osler, Hoskin & Harcourt LLP advised the IESO as procurement counsel with a team consisting of Jake Sadikman, Richard King, Rocco Sebastiano, Elliot Smith, Jagriti Singh and Cole Taverner (Energy & Infrastructure).