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St. Clair Transmission Line Project

Energizing life for communities

As the population grows in southwestern Ontario, safe and reliable power is needed to improve reliability for homes and businesses, secure and diversify supply, and create opportunities for industries to locate in the area.

Expected Completion Date : 2028

Current Project Phase : Planning

Environmental Study Report Report Highlights
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Project Overview

Hydro One is proposing to construct 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 and security, 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.

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


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.

Project map

Benefits to the community

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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.

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Clean Energy

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

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Food Supply

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

Planning process

An integral part of this project requires the completion of a Class Environmental Assessment (Class EA), in accordance with the Ontario Environmental Assessment Act. Rooted in community engagement and consultation, the Class EA evaluated proposed alternative routes for the new line that minimize social, economic and environmental effects.

As Hydro One continues its design and study of the preferred route, we are committed to listening and incorporating your feedback into the planning stages of this project. We want to ensure all directly affected property owners understand the work required on their property and continue have the opportunity to provide feedback.

Following completion of the Class EA, the project will also require Ontario Energy Board (OEB) approval under Section 92 (Leave to Construct) of the Ontario Energy Board Act.

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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
Completion of detailed design and other permits and approvals, including Section 92 approval from the Ontario Energy Board.
Proposed Line in-service
*Dates are subject to change.
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Frequently Asked Questions

What is the need for the project

Hydro One is proposing to construct a new double-circuit 230 kilovolt transmission line between our Lambton Transformer Station, located in St. Clair Township and our Chatham Switching Station, located in the Municipality of Chatham-Kent.

To support this growth in southwest Ontario, the IESO requested Hydro One begin development work in March 2021 to build a new transmission line between our Lambton Transformer Station in and Chatham Switching Station.

Why was Route 2 selected as the preferred route?

Since February 2022, we’ve sought feedback and completed studies to identify and evaluate five route alternatives to select a preferred route. Input from Indigenous communities and residents, agencies and the public has been crucial, as well as environmental, technical, and other considerations, in determining the preferred route for the new line.

We used this data to evaluate the route alternatives and select a preferred route that balances the natural and socio-economic environments, technical and cost considerations, and Indigenous culture, values and land use.

How is feedback used as part of the Class Environmental Assessment process?

Your feedback is important to the successful development this new transmission line. Since the beginning, we heard from residents through meetings, email, phone, workshops, community open houses and surveys/comment forms. The local knowledge we have received about the environment, including the natural and socio-economic environment, helped us to select a route that minimizes adverse effects to the environment. On balance, the route scored favorably in the natural environment, Indigenous culture, values and land use and socio-economic areas.

Our goal is to continue hearing as much local input as possible about the project so that we can work towards building a line that community members and property owners can see their feedback reflected in.

Please provide feedback at anytime by contacting Hydro One Community Relations at or 1-877-345-6799.

How big are the towers going to be?

With the selection of a preferred route, we can begin the detailed engineering design, which will influence the size, location and number of towers required, as well as the right-of-way width.

That said, Hydro One has been powering southwestern Ontario for over 100 years and we know the typical right-of-way required for a 230-kilovolt transmission line is approximately 46 metres in width. We also anticipate the typical tower footprint will range from 6 metres x 6 metres to 12 metres x 12 metres, depending on the tower design. The typical tower height is influenced by environmental conditions like topography, and we anticipate will range between 30 metres and 60 metres.

How will affects to agricultural operations be mitigated?

We know the important role farmers have in supporting Ontario’s economy and we are committed to minimize potential affects to agricultural operations during and after construction. These measures, as outlined in Chapter 7 of the Environmental Study Report include, using existing access as much as possible and building new roads to the minimum length and width, avoid and protect tile drains, proactively communicate work activities with farmers that may disturb livestock and consult on mitigation measures such as moving or containing the livestock, restore land following construction activities.

Public Consultation documents

The St. Clair Transmission Line was subject to the Class Environmental Assessment for Minor Transmission Facilities (2022) in accordance with the Ontario Environmental Assessment Act. The Class EA is a streamlined planning process ensuring that applicable projects are planned and carried out in a manner that is efficient and environmentally acceptable. Hydro One began a Class EA in February 2022, which was completed and submitted to the Ministry of the Environment, Conservation and Parks on February 5, 2024.

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

June 05, 2023

Preferred Route

Hydro One announced Route 2 as the preferred route for the proposed St. Clair Transmission Line. After a thorough evaluation of five options, this alternative was selected as 80 percent of the route...

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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.

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

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