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St Thomas Line Project

Energizing life for communities

Hydro One is committed to energizing life for communities, people, and businesses across Ontario. As industry grows, so does the need for safe, clean, and reliable power.

Current project phase : Planning

Expected in-service date : 2027

Overview Community benefits
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Project overview

The new St. Thomas Line project will power Ontario’s growing electric vehicle industry, support future economic growth and help bring thousands of jobs to southwest Ontario by connecting the new electric vehicle battery cell manufacturing facility in the City of St. Thomas to Ontario’s clean electricity grid. Hydro One is starting a Class Environmental Assessment (EA) for an approximately 20-kilometer, 230-kilovolt double circuit transmission line. This line will extend from our existing hydro corridor north of Highway 401 in the City of London to the newly planned Centennial Transformer Station in St. Thomas.

We’re here to help you

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


Hydro One drop in hours available at the Holiday Inn Express

Hydro One will host community drop-in sessions twice a week through the summer to continue gathering local knowledge and input on the three proposed route options for the St. Thomas Line project. Every Tuesday and Wednesday until August 28, community members can walk in or schedule an appointment between 10:00 a.m. and 3 p.m. at the Holiday Inn Express & Suites in St. Thomas to meet with the project team and provide their feedback or have their questions answered.

To book an appointment, email us at or call 1.877.345.6799.

Holiday Inn Express

Every Tuesday and Wednesday until August 28th

10:00 a.m. - 3:00 p.m.

Holiday Inn Express & Suites

275 Highview Dr, N5R 5Y5

Get directions

Project map

The St. Thomas Line will extend between London to St. Thomas. Currently, we are studying three route alternatives and their variations. As feedback is an important part of the planning process for the project, we encourage you to view our interactive map to get a more in-depth view of the routes we are studying and share comments or information that you feel is important to you or your community.

Project map

Benefits to the region

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Economic Growth

Southwest Ontario continues to attract large investments to the region. By providing the power needed to energize the new manufacturing facility, this new transmission line will support thousands of new jobs and future economic growth for St. Thomas and surrounding communities.

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Clean Energy

This project will deliver a safe and reliable supply of clean energy, playing a pivotal role in the decarbonization of the auto manufacturing industry.

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Growing Industry

The transmission line will support the largest electric vehicle-related investment in Ontario’s and Canada’s history, which will strengthen the auto manufacturing industry and work to meet the demand for electric vehicles now and into the future.

Planning process

Minimizing the effects of our projects and operations on the environment is important to us. The planning of this project will follow the Class Environmental Assessment for Minor Transmission Facilities (2022) in accordance with the Ontario Environmental Assessment Act. This planning process applies to transmission infrastructure projects that are carried out routinely and have predictable environmental effects that can be readily managed. Once the Class EA process is successfully completed, construction could commence in early 2025 to meet the in-service date of 2027.

Rooted in engagement and consultation, the Class EA ensures that potential natural, economic, social and cultural effects are thoroughly considered before a project begins. Engagement with Indigenous communities, landowners, businesses, stakeholder groups, government agencies and other interested parties is critical to help us select the preferred routs that considers the needs and interests of the region.

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Anticipated project schedule

January 2024
Commencement of Class Environmental Assessment
February 2024
Community Open House #1; Introduction of project, presentation of proposed route alternatives
Fall 2024
Community Open House #2; Update on project and selection of preferred route
Spring 2025
Draft Environmental Study Report for public review
Summer 2025
Finalize Class Environmental Assessment
Late 2025
Construction to follow approvals
Proposed Line in-service
*Dates are subject to change.
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Frequently asked questions

How did you identify the route alternatives?

Prior to the start of the Class Environmental Assessment, we conducted preliminary work to identify route alternatives. We mapped out local features and constraints such as waterbodies, residential areas, environmentally significant areas, and looked for opportunities to parallel linear infrastructure where feasible. Based on that information, we are studying three route alternatives and their variations.

How will the preferred route be selected?

Engagement is vital to the planning process. We will meet with Indigenous communities, members of the public, businesses, government agencies and other interested parties to better understand the region and local interests. As a part of our environmental assessment, we will also collect data, conduct environmental field surveys and perform technical assessments. Using both the feedback and information collected, each route will be evaluated and compared to ultimately selected a preferred route.

How will feedback be used?

Your feedback is an important part of the planning process. It will help us develop and prioritize the criteria we will use to evaluate and compare each route in the evaluation process, as well as identify potential ways to avoid, mitigate or restore potential project impacts.

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

Public consultation documents

Notice of commencement — January 2024

Open house resources

Land acknowledgement

Hydro One acknowledges that we are on the traditional territory of the Anishinaabeg, Haudenosaunee, Attawandaron, and the Huron Wendat peoples. Hydro One also acknowledges that these lands are covered by the Upper Canada Treaties.

Hydro One understands that Indigenous nations have been the caretakers of Turtle Island since time immemorial. We also understand that our Nation’s history was not reflective of the friendship we strive for today. We are all Treaty People, and as Treaty people we must honour our obligations to work with First Nations, Metis and Inuit communities to achieve reconciliation. With a commitment to friendship and our pursuit of reconciliation, perhaps we can improve on our past and energize our combined futures.

We recognize these lands as being home to many First Nations, Metis and Inuit people, and we are thankful to be welcomed on these lands as partners in our shared future among the diverse Indigenous people who call these lands home today.

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

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