York Region


For regional planning purposes, the region consists of Southern and Northern York Region to reflect the layout of the region's electricity infrastructure. Southern York Region roughly includes the municipalities of Vaughan, Markham and Richmond Hill, while Northern York Region roughly encompasses the municipalities of Aurora, Newmarket, King, East Gwillimbury, Whitchurch-Stouffville and Georgina. Because the electricity system was not developed along municipal boundaries, customers in some areas near the boundaries of York Region are supplied from infrastructure outside the scope of this IRRP, and some customers in Durham and Simcoe counties are supplied from the York Region infrastructure.

In addition, a portion of Vaughan is being studied through a separate process as part of the GTA West sub-region.

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 York Region

The regional planning cycle is underway for York Region, with an Integrated Regional Resource Plan (IRRP) anticipated to be posted in Q4 2019.

A Scoping Assessment Outcome Report and Terms of Reference for GTA North (York Region) IRRP was finalized and posted in August 2018, following a two-week comment period.

Visit here for more information about the Regional Planning Process. See below for past regional planning activities in this region.

GTA North 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 representatives from the three LDCs in the area - Newmarket-Tay Power, Alectra Utilities, Hydro One Networks Inc. (also Transmitter), and the IESO.

2015 Regional planning process outcome

York Region

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

In the near term, three transmission projects are recommended to address capacity and reliability needs; these projects are already under development by Hydro One and Alectra Utilities (formerly PowerStream).

In the medium to long term, York sub-region's electricity system is expected to reach its capacity to supply growth in the early to mid-2020s based on current projections. If the growth materializes, there will be a need for additional new supply in the region. The Working Group will seek community input on possible solutions.


2015 GTA North IRRP

2015 GTA North IRRP – Appendix


Key Resources

Past Local Advisory Committee meetings


Terms of Reference

Terms of Reference Addendum

OPA Letter to Hydro One - York Region

OPA Letter to PowerStream re: Siting Vaughan #4 MTS

PowerStream Letter to OPA re: York Region Planning Supply Study

IESO Letter to Alectra Utilities and Hydro One (April 21, 2017)

FAQs – Addressing Electricity Needs in the Markham-Richmond Hill Area (April 21, 2017)


Related Studies

The IESO and the Ministry of Transportation have announced a joint corridor identification study on a proposed land corridor in the Northwest Greater Toronto Area (NW GTA). The purpose of this study is to identify land to be protected for future multi-purpose linear infrastructure (such as transmission lines and transportation infrastructure) to ensure it can be accommodated if and when the need arises. The anticipated long-term need for new transmission in the NW GTA has been documented by the IESO through submission to official plans and the regional planning process, and has been highlighted in the 2017 Long-Term Energy Plan. Although the area of study is primarily centred in the GTA West planning region, parts extend into GTA North. The study will be conducted in phases and is expected to be complete within nine to 12 months. For further information and to access the study, please visit the Ministry of Transportation website.