Ottawa sub-region


With a growing population of about 900,000 people and a peak demand of about 1,800 MW, the Ottawa sub-region is one of the largest electricity planning regions in Ontario. The sub-region has a diverse mix of electricity customers including government and commercial facilities, light industry, and residential consumers.

The Ottawa sub-region encompasses the City of Ottawa, including the Greenbelt, Kanata, Nepean and Orléans.

Historical Context

In the 1950s, the National Capital Commission established a Greenbelt around central Ottawa in an effort to contain growth. While the downtown core has continued to grow, development in recent years has largely occurred in the communities outside the Greenbelt.

Supplying these communities is challenging because the existing transmission system consists of long, single-circuit 115 kV or 230 kV lines with limited supply diversity. The reconfiguration of this older system presents challenges to meeting reliability criteria under extensive urbanization and load growth.

Community Engagement

The IESO engages with local and regional communities to seek input to help inform planning activities. Learn more about engagement on the current planning cycle.

See engagement materials on the previous planning cycle.

Regional Planning Activities in the Ottawa Area sub-region

The regional planning cycle is underway for the Ottawa Area sub-region, with an Integrated Regional Resource Plan (IRRP) anticipated to be posted in Q2 2019.

A Scoping Assessment Outcome Report and Terms of Reference for the Ottawa Area IRRP was finalized and posted in September 2018, following a two-week comment period.

For more information, see Regional Planning Process. See below for past regional planning activities in this region.

Ottawa Area Technical Working Group

A Technical Working Group will follow the regional planning process to discuss opportunities to identify and meet local electricity needs. For the purposes of this regional planning activity, the Working Group will consist of the local distribution companies in the area – Hydro Ottawa and Hydro One Networks Inc. (also Transmitter), and the IESO.

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.

Previous Regional Planning Studies

Regional Planning Process Outcome (IRRP)

Ottawa Area sub-region

The regional planning cycle begun in 2013 for the Ottawa Area sub-region was completed in April, 2015 and an Integrated Regional Resource Plan (IRRP) was released.

In the near-term, four transmission and distribution reinforcement projects are recommended to address demand growth and reliability needs; work on these projects is underway by Hydro One. The Working Group will ask for community input on addressing the need for additional supply tomeet electricity demand growth in the South Nepean area, which is expected to be required around 2020.

Key Resources

2015 Ottawa Area IRRP

2015 Ottawa Area IRRP – Appendix


Past Local Advisory Committee Meetings


Terms of Reference

Terms of Reference Addendum

OPA Letter to Hydro One – Ottawa

IESO Hand-off Letter to Hydro Ottawa and Hydro One (April 25, 2016)

FAQs – Electricity Needs in South Nepean Area (April 25, 2016)