Reliability Outlook


Cover of Reliability Outlook

The quarterly Reliability Outlook (formerly known as the 18-Month Outlook) presents Ontario’s demand forecast and associated drivers, resource adequacy projections and the assumptions that inform them, as well as an assessment of operability and the province’s transmission assets.

As part of the IESO’s commitment to open and transparent planning, beginning in December 2018, the IESO extended the traditional 18-month planning horizon for an additional 42 months, providing a five-year assessment of reliability. Published every June and December, these extended outlooks address the drivers that can affect resource adequacy, and require the IESO to address associated reliability risks through outage management.

In addition, The IESO is making its Transfer Capability Assessment Methodology for the Near-Term Transmission Planning Horizon publically available. The Ontario Transmission System document was consolidated with this Transfer Capability Assessment Methodology document. Operating Limits previously documented in the Ontario Transmission System document are now available in the Reliability Outlook Tables.

Here are the most recent issue and related documents.

Spring 2020: April 2020 to September 2021

  • Reliability Outlook Report  (released March 24, 2020)
  • Reliability Outlook Interim Update: in Microsoft Excel Spreadsheet format (released May 20, 2020)
  • Reliability Outlook Interim Update – Demand Forecast: in Microsoft Excel Spreadsheet format (released May 20, 2020). The IESO has revised its demand forecast for this 18-Month Outlook; some background and context for this revision can be found in the document below.
  • Reliability Outlook Interim Update – Background and Context: PDF (released May 20, 2020). These slides contain some explanatory details of revisions made to the demand forecast to account for the impacts of COVID-19 on electricity demand. These were presented as part of a public information session on May 20, 2020; the full presentation can be found on the Public Information Sessions webpage under Electricity system impact of COVID-19 webinar #2.
  • Reliability Outlook - Tables in Microsoft Excel spreadsheet format (released March 24, 2020)
  • Methodology to Perform the Reliability Outlook contains information regarding the methodology used to perform the demand forecast, resource adequacy assessments, and transmission adequacy assessments in this Outlook report.
  • Transfer Capability Assessment Methodology documents the methodology used for performing assessments of Transfer Capability of the Ontario Bulk Electric System (BES) for transmission planning studies.  This methodology is in accordance with the North American Electric Reliability Corporation (NERC) standard FAC-013-2. The IESO has also utilized this methodology for the transmission assessment beyond the first 18 months in the Reliability Outlook.

For earlier reports, including Ontario Reliability Outlook and 10-year Outlooks see the Document Library.

Submitting of Reliability Assessment Information

Market participants are required to provide information to the IESO to enable it to conduct reliability assessments. These submissions are required each calendar year.

For submission deadlines for input information for the Reliability Outlook and other reliability assessments, see the Calendar for Submission of Reliability Assessments Information.

Related Information

Ontario Reserve Margin Requirements: 2020 - 2024 reports on the operational planning reserve requirements to meet the NPCC resource adequacy design criterion over a five-year window.