Hydro One has announced the start of construction on the St. Clair Transmission Line.

The 64-kilometre, double-circuit 230 kilovolt (kV) transmission line will connect the County of Lambton and Municipality of Chatham-Kent, while expanding the existing Chatham Switching Station and Lambton Transformer Station and converting the existing Wallaceburg TS to 230 kV by 2028.

The new transmission line will provide 450 MW of power to the region – the equivalent of adding enough power for a city of the size of Windsor – and enable the expansion of electric vehicle manufacturing and farming operations in the region.

Southwestern Ontario is the site of some of the fastest industrial and population growth in the province, fueled by Canada’s first EV and battery manufacturing facilities, expanded greenhouse operations and major residential development.

With electricity demand in the Windsor-Essex and surrounding Chatham region expected to grow to more than 2,300 megawatts (MW) over the next 10 years and provincial demand projected to increase 75 percent by 2050, the provincial government says ensuring a reliable electricity system in the region is critical to keeping jobs and investment.

"With today's groundbreaking we're building more than infrastructure, we're taking another step forward to help power the future for the region and province," said Hydro One CEO Megan Telford.

The St. Clair Transmission Line is part of a network of projects including the Chatham to Lakeshore line that was energized in late-2024 and Longwood to Lakeshore transmission lines, being developed in collaboration with five First Nation partners in the region. Through its First Nation Equity Partnership Model, Hydro One is offering First Nation partners a 50 percent equity stake in the transmission line component of the project.

"This project highlights the vital role First Nations have in shaping Ontario's energy future," said Janelle Nahmabin, Chief of Aamjiwnaang First Nation. "By bringing Indigenous knowledge and leadership to the table, we are helping to build a stronger, more resilient electricity system. We look forward to continuing our partnership with Hydro One as we work together to power growth, opportunity, and a brighter future for both our community and all of Ontario."

Construction of the project is anticipated to generate approximately 70 new jobs and will be led by Forbes Bros. Group of Companies and Black & McDonald Limited.

The project is estimated to cost $472 million.