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Region Overview

Northwestern Ontario (the Northwest) consists of the districts of Kenora, Rainy River, and Thunder Bay, which is roughly the area north of Lake Superior stretching from the Wawa area in the east and the Manitoba border in the west. The region accounts for approximately 60 per cent of the land area in the province and approximately two per cent of Ontario’s total population. Roughly half of the population in the Northwest resides in the city of Thunder Bay and the remaining population resides in smaller communities across the region.

This region is divided into Greenstone-Marathon, North of Dryden, West of Thunder Bay and Thunder Bay sub-regions.

Region's Local Distribution Companies
  • Atikokan Hydro Inc.
  • Fort Frances Power Corporation
  • Hydro One Networks Inc.
  • Synergy North
  • Sioux Lookout Hydro Inc.




Map: Northwest Ontario
 

Current Status

The third regional planning cycle for this region was kicked off in July 2025 beginning with the Needs Assessment (NA). The NA report for this region was completed in September 2025. Based on load forecasts provided by Local Distribution Companies (“LDC”), existing directly connected customers, recent customer connection applications, information provided by regional municipalities, proactive groups, and existing government initiatives and strategies, the TWG recommends a comprehensive electrical plan for the region. In recognition of the distinctive, urgent and ever evolving demands of customers in the Northwest region – such as mining operation, data centers, forestry companies and large industrial manufacturers, and in accordance with the Transmission System Code (“TSC”), the TWG has agreed to begin the Scoping Assessment (“SA”) phase promptly, which will then lead into development of the Integrated Regional Resource Plan (“IRRP”) and finally completing the regional planning cycle with a RIP.​

 
Accomplishment (Most Recent Shown First) Status Completion Date
Needs Assessment (3rd Cycle)
 Completed
 September 2025
​Regional Infrastructure Planning (2nd Cycle)
 ​Completed
 ​​August 2023
​Integrated Regional Resource Planning (2nd Cycle)
 ​Completed
 ​​January 2023
Local Planning (Sam Lake DS) Completed January 2023
Scoping Assessment (2nd Cycle) Completed January 2021
Needs Assessment (2nd Cycle) Completed July 2020
Regional Infrastructure Planning Completed June 2017
Integrated Regional Resource Planning Thunder Bay sub-region Completed December 2016
Integrated Regional Resource Planning West of Thunder Bay sub-region Completed July 2016
Integrated Regional Resource Planning Greenstone-Marathon sub-region
 Completed June 2016
Integrated Regional Resource Planning North of Dryden sub-region Completed ​January 2015

*The completed reports are available below.

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Relevant Documents

Regional Infrastructure Planning (RIP)
Name Completion Date
Northwest Ontario RIP Report (2nd Cycle)  August 2023
Northwest Ontario RIP Report  June 2017
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Integrated Regional Resource Planning (IRRP)
Name Completion Date
​Northwest Ontario IRRP – Report (2nd Cycle)​​ ​January 2023
Northwest Ontario IRRP – Appendices (2nd Cycle) ​January 2023
Thunder Bay Sub-Region IRRP – Report December 2016
Thunder Bay Sub-Region IRRP – Appendices December 2016
West of Thunder Bay Sub-Region - IRRP Appendices July 2016
West of Thunder Bay Sub-Region - IRRP Report July 2016
Greenstone - Marathon Sub-Region - IRRP Appendices June 2016
Greenstone - Marathon Sub-Region - IRRP Report June 2016
North of Dryden Sub-Region - IRRP Report January 2015

Needs Assessment (NA) & Scoping Assessment (SA)
Name Completion Date
Northwest Ontario NA – Report (3rd cycle) September 2025
Northwest Ontario SA – Report (2nd Cycle) January 2021
Northwest Ontario NA - Report (2nd Cycle) July 2020
Local Planning (LP)
Name Completion Date
Local Planning - Report (Sam Lake DS) January 2023
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Additional Documents
Name Completion Date
Letter to NW Region Participants  April 2014