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St. Clair Transmission Line

Energizing life for communities

Hydro One continues to invest and build in the southwest to improve resiliency and reliability so communities have electricity when and where they need it.

Expected completion date: 2028

Current project phase: Construction

Hydro One employee at a open house helping community member

Project overview

Hydro One is constructing a new transmission line in the County of Lambton and Municipality of Chatham-Kent. This project involves constructing a double-circuit 230 kilovolt transmission, expanding the existing Chatham Switching Station and Lambton Transformer Station (TS) and converting the existing Wallaceburg TS to 230 kV.

This project is part of a network of electricity infrastructure projects that will support the regions’ economic growth. Once built, the St. Clair Transmission Line will support local food supply, economic development and job creation. We’re completing the planning stage now, so that we can be ready to bring additional power to the region when and where it’s needed.

We’re here to help you

To provide comments or to be added to the project contact list, please call or email:

1-877-345-6799 Email us today

Biodiversity initiative

Hydro One is investing in local biodiversity projects through the St. Clair Transmission Line Biodiversity Initiative to help strengthen the region's natural environment.

As we build a safe, reliable and resilient grid to meet growing electricity demand and adapt to climate change, we're also supporting local biodiversity and healthy ecosystems.

Through this initiative, Hydro One is funding local projects that create or enhance habitat and deliver lasting environmental benefits for future generations.

Submissions are being reviewed

From July 3 – September 9, 2026, Hydro One accepted letters of interest proposing biodiversity projects for the St. Clair Transmission Line. Submissions are now being reviewed.

Proposed projects will be evaluated based on ecological values, value-added factors (i.e., non-ecological values such as educational or research benefits) and cost to implement.

Projects must:

Be located on secured properties, so that habitat benefits are protected in perpetuity
Demonstrate a clear need for Hydro One support
Include a plan to move forward in the near term.

Priority will be given to projects located within the tertiary watersheds crossed by the St. Clair Transmission Line.

Questions? Please contact Paul Dalmazzi at Paul.Dalmazzi@HydroOne.com

Project map

Since the start of this project in February 2022, we have received feedback and completed environmental studies to select a route that minimizes the impacts to the natural environment and leverages the opportunity to replace existing electrical infrastructure and repurpose existing transmission line corridors.

Interactive Map

Benefits to the community

Economic Growth

The new line will unlock economic potential and job creation in the region. Along with powering homes and businesses, it will support key areas, including electric vehicle technology and the agriculture sector.

Clean Energy

The project will provide a reliable supply of clean electricity, which means communities and businesses can continue to grow.

Food Supply

The line will support local food supply including helping farmers and greenhouse producers thrive.

Construction updates

Construction is planned to begin mid-2025 and will be completed by Hydro One partner contractor, Forbes Bros. To learn more about our construction activities and speak directly with our project team members, please visit one of our upcoming community houses.

Anticipated project schedule

February 2022

Notice of Commencement

March 2022

Virtual community open house #1; Introduction of project

Fall 2022

Community open house #2; Update on project

June 2023

Community open house #3; Selection of Preferred Route

Fall 2023

Draft Environmental Study Report (ESR) 30-day comment period

February 2024

Submit final ESR and complete the Class EA process

2025-2026

Obtain Section 92 approval, completion of detailed design and construction start

2028

Proposed line in-service

*Dates are subject to change.

Frequently asked questions

What are your general working hours?

Our contractor will generally work Monday to Sunday between 7:00 a.m. – 5:00 p.m. with additional time required for certain activities.

What is the construction schedule?

We anticipate construction will begin summer 2025 and the line will be in service before the end of 2028. Our contractor Forbes Bros will initially begin work in the Wallaceburg area, proceed to Chatham and move northwest towards St. Clair. Forbes will also work directly with affected property owners prior to construction. Join our upcoming community open houses on May 21 and 22 for details.

Will you need to build access roads?

Our contractor will be required to build temporary access roads along the route and will work with property owners. Access roads will be a combination of gravel with some wooden mats in a few sections.

How heavy is your equipment?

Forbes Bros will use a variety of equipment such as light-duty trucks to mobile cranes. The heaviest pieces of equipment (mobile cranes) are approximately 150,000 lbs, with weight spread over several axles. In addition, crews will use wooden mats and other protective measures around the usage of heavy equipment.

Who can I contact if I have concerns about construction activities on my property?

If you have any property specific questions or would like further information, please contact our Community Relations team at 1.877.345.6799 or Community.Relations@HydroOne.com.

Public consultation documents

Hydro One has received approval from the Ontario Energy Board (OEB) to construct the St. Clair Transmission Line, signaling another important milestone for energy infrastructure in southwest Ontario. This critical investment will enable economic growth by meeting the needs of new and growing industries and help attract future jobs to the region.

Environmental Study Report Report highlights

Open house panels - May 2025

View the pre-construction open house panels

Read the final Environmental Study Report

Final Environmental Study Report (.PDF - 5 MB) Final Environmental Study Report Highlights (.PDF - .8 MB) Appendix A (.PDF - 1 MB) Appendix B (.PDF - 64 MB) Appendix C (.PDF - 381 MB) Appendix D (.PDF - .5 MB) Notice of Completion (.PDF - 1.3 MB)

Preferred route announcement community open houses — June 2023

Download the Notice of Preferred Route and Invitation to Community Open Houses Download the Preferred Route Open House Panels Watch this video to learn more about the Preferred Route

Virtual community open house & live discussion — March 2023

View the March 9, 2022 live discussion View the March 10, 2022 live discussion Download the virtual open house panels

Notice of commencement — February 2022

Download the Notice of Commencement Download the Newspaper Ad

In-person and virtual community open houses — October 2022

Download the in-person open house panels View the October 23, 2022 live discussion

Land acknowledgement

Hydro One acknowledges that the St. Clair Transmission Line Project is proposed on the ancestral lands of the Anishinaabe and is now home to many diverse First Nations, Inuit and Métis people. Hydro One understands that Indigenous Nations have been here since time immemorial and are stewards what many refer to as Turtle Island. We are all Treaty People and with a commitment to friendship and our pursuit of reconciliation, we are thankful to be welcomed on these lands as partners in our shared future so we can improve on our past and energize our combined futures.

The latest news on St. Clair

May 28, 2024

Application filed

Hydro One filed an application with the Ontario Energy Board to construct a new 230 kV transmission line between Lambton TS and Chatham SS.

June 05, 2023

Final (EA)

Hydro One has submitted the final Environmental Study Report to the Ministry of Environment for the St. Clair Transmission Line project.

November 06, 2023

(EA) Feedback

Today, Hydro One released the Draft Environmental Study Report for the St. Clair Transmission Line project for public review and comment.

To provide comments or to be added to the project contact list, please connect with us

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