GTA West

Map of Ontario showing 21 electricity planning regions

Area Overview

The GTA West region includes the Regional Municipalities of Halton and Peel, and the Municipalities of Brampton, South Caledon, Halton Hills, Mississauga, Milton, Burlington, and Oakville. The GTA West region also encompasses the Northwest Greater Toronto Area sub-region. GTA West and Peel/Halton Region are often used interchangeably throughout electrical studies.

The local distribution companies providing services to customers in the area include:

  • Alectra Utilities
  • Burlington Hydro Inc.
  • Halton Hills Hydro Inc.
  • Hydro One Networks Inc.
  • Milton Hydro Distribution Inc.
  • Oakville Hydro Electricity Distribution Inc.

Community Engagement

The IESO engages with local and regional communities to seek input to help inform planning activities. There are currently no active regional planning engagement activities for this region. See Key Resources below for the latest planning documents.

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Regional Planning Progress Update

The regional planning cycle was completed for GTA West Region with the release of an Integrated Regional Resource Plan (IRRP) and supporting Appendices in July 2021. The IRRP recommends a plan to address electricity needs through low-cost technical transmission solutions, while long-term needs present an opportunity to explore emerging alternative solutions, which was a key area of feedback received during the engagement initiative for the development of the plan. Overall, the IRRP concludes that the electricity infrastructure is in a strong position to meet and support future long-term growth in the GTA West.

A regional Infrastructure Plan (RIP) led by Hydro One was published in February 2022.

Key Resources

Related Studies

The IESO and the Ministry of Energy have initiated a joint study to identify land to be protected for a future transmission corridor to support anticipated long-term growth in demand for electricity in the GTA West region. Part of ongoing efforts to plan today to avoid future costs to electricity ratepayers, this initiative will ensure that transmission needs – documented through the regional planning process – in the study area can be accommodated if and when they arise.

Although the area of study is primarily centred in the GTA West planning region, parts extend into GTA North. This study is separate from but will continue in parallel with the Ministry of Transportation’s (MTO) GTA West Transportation Corridor Route Planning and Environmental Assessment (EA) Study.

Update: The study team released a revised study area related to the Northwest GTA Transmission Corridor Identification Study. The study is ongoing and comments will continue to be considered with subsequent study milestones. A Decision Summary is now available on the Environmental Registry of Ontario’s webpage which outlines the comments heard and how they were considered in this first phase of the study.

Comments and input regarding this study, to contact the project team or to be added to the mail list are encouraged to email