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Sector Participants > Engagement Initiatives > Engagements > Customer Reliability Review

Customer Reliability Review

The Independent Electricity System Operator (IESO) is planning to review and report on the technical criteria used to assess customer reliability and supply security in order to identify and evaluate options for local area enhancements. Consideration will be given to potential improvements to customer load restoration criteria, including in remote areas. The impact of cost and funding requirements on electricity consumers, distribution and transmission utilities and other stakeholders that may result from any proposed changes will also be assessed. The results from this review will be recommendations for revisions to IESO’s customer reliability criteria.

For this review, customer reliability is investigated based on the reliability that the IESO-Controlled Grid provides in terms of how frequently power to customers is interrupted and the duration of the interruption.  The IESO-Controlled Grid is generally defined as the portion of the provincial power system > 50 kV and does not include low voltage services provided by Local Distribution Companies (LDCs).

Many different organizations are involved in ensuring a reliable supply of electricity to customers.  The Ontario Energy Board (OEB) requires transmitters to develop performance standards at their delivery points.  The OEB also requires LDCs to report on customer reliability and to either deliver the historical level of performance at a progressively lower cost or superior performance at similar costs.  The IESO is responsible for planning the IESO-Controlled Grid in a manner that ensures that the amount of load interrupted and the duration of the interruption is within the IESO’s standards as specified in the Ontario Resource and Transmission Assessment Criteria (ORTAC).

The IESO will be seeking community and stakeholder feedback on the customer experience of reliability and customer views of section 7 of ORTAC. This information will be used to develop and confirm IESO understanding of the need and to inform recommendations for revisions to ORTAC. Feedback will also be sought on the draft alternatives and recommendations prior to finalizing the findings of the initiative.

Additional details on the IESO’s plans to engage communities and stakeholders throughout the process can be found in the engagement plan. All comments and enquiries on this engagement can be directed to

Documents referenced on this page, but not posted, can be obtained by contacting with a link to the web page that lists the document and advise whether it needs to be provided in an accessible format. Please allow a minimum of one business day for a response.

Schedule of Activities

Date  Activities Expected Actions 

July 2019

Customer Reliability Review - Phase 1 Conclusion Memo


November 20 -December 11, 2018

Window for written submissions

Feedback will specifically be requested on the customer experience of reliability delivered by the IESO-controlled grid and implications of the experienced reliability.

November 20, 2018

Customer Reliability Review Public Webinar

Recorded Presentation

  • Presentation
  • Feedback Form

Overview of customer reliability review initiative and objectives. Outlining input being sought in Phase 1 of engagement.

November 7-8 & 21-22, 2018

Regional Electricity Forums


October 22-24, 2018

First Nations Energy Symposium