Capacity Auction

The annual Capacity Auction is the competitive procurement mechanism in the IESO’s Resource Adequacy Framework that secures the capacity needed to meet the balance of Ontario’s resource adequacy needs on a short-term basis. The Capacity Auction enables participation from existing and non-committed demand response, generation, storage and import resources that compete to make their capacity available. Capacity suppliers who secure an obligation in one or both of two, six-month obligation periods (summer and winter) can receive a payment, based on the auction clearing price, for making their capacity available during a window of hours on each business day.

The IESO continues to develop enhancements to the Capacity Auction, in consultation with stakeholders, to ensure the auction continues to procure sufficient capacity to meet incremental resource adequacy needs, provide a stable and transparent investment signal to market participants, drive competition and promote ratepayer value. 

Parties interested in participating in an upcoming Capacity Auction are encouraged to review the associated Market Rules, Market Manuals, and information on this webpage.

Please contact if you have any questions regarding the Capacity Auction.

See archive section below for past Capacity Auction results and supporting materials.

eLearning Modules and Q&A Sessions

The IESO has a suite of training offerings available to prepare potential participants who may be looking to participate in this year’s Auction. The IESO will automatically register existing Capacity Auction contacts for the eLearning modules. If you just recently registered, are not yet a Capacity Auction contact in the IESO’s online registration system (Online IESO) and/or would like to register for the Capacity Auction eLearning modules, please email IESO Customer Relations at and include the following:

  • Organization name (name registered with IESO)
  • First and Last name
  • eLearning Module(s) you would like to be enrolled in
  • Email that you would like us to use for your eLearning account registration (preferably your organization email address)

Existing and prospective participants are encouraged to attend one of two Q&A sessions. These sessions are being held to address questions that may arise while completing the modules. To register, please follow the links below:

Session #1: July 24, 2024 1:00PM – 2:30PM EDT

Session #2: July 31, 2024 1:00PM – 2:30PM EDT

Past Capacity Auctions

Historic rules, pre- and post-auction reports and demand response resource-related timelines are found below:

Further auction specific information by auction year is found below:

Demand Response Auction

For information relating to the former Demand Response Auction, including Pre-Auction Reports, Post-Auction Reports and other related documents visit the Demand Response Auction webpage.