Ontario and Toronto to Build Third Transmission Line, Powering the Future of Downtown Growth

Toronto, ON — The Ontario government and the City of Toronto are moving forward with a landmark infrastructure project: the construction of a third electricity transmission line into the city’s downtown core. The historic project is aimed at supporting the growing energy needs of new homes, businesses, and transit systems while reinforcing the reliability of Toronto’s power grid for decades to come.

Announced by Minister of Energy and Mines Stephen Lecce, the new line is being developed in partnership with Toronto and follows a year of technical analysis and public consultations led by Ontario’s Independent Electricity System Operator (IESO). The initiative is part of the province’s broader plan to make Ontario the most competitive jurisdiction for investment in the G7.

“With our electricity demand expected to double by 2050, we are acting now to ensure the power is in place to drive Toronto’s growth,” said Minister Lecce. “This transmission line will help energize transformative projects like the Ontario Line and new neighbourhoods such as the Port Lands and East Harbour.”

Hey Toronto 👋🏼

Unlike the government before us, we are planning ahead to meet Toronto’s energy needs.

We are saying yes to a third new transmission line into the downtown core that will power 285,000 homes and help attract job creating investment.

Building for the future… pic.twitter.com/g5NJFqd5ht

— Stephen Lecce (@Sflecce) June 4, 2025

Currently, Toronto’s grid is supported by just two supply corridors — one from Manby Transmission Station in the west and one from Leaside Transmission Station in the east. Both are forecasted to reach their maximum capacity within the next decade. The third line will ensure the city can handle increasing electricity demand without disruptions or reliance on neighbouring jurisdictions.

Mayor Olivia Chow welcomed the collaboration: “Toronto is growing. As we build more housing, transit, and jobs, we’re going to need the power that sustains our progress. We’re ready to work with the province to make this project a reality.”

The IESO has outlined three possible routes for the new line:

• Overland from Pickering to Leaside using existing corridors.

• Hybrid route from Pickering to the Port Lands, including underground cables through Warden Transmission Station.

• Underwater route through Lake Ontario from Pickering or Darlington to the Port Lands.

All proposed options aim to minimize land use impacts while providing scalable long-term solutions. The IESO will continue consultations over the summer with Indigenous communities, the City of Toronto, and stakeholders before issuing a final recommendation by the end of August.

Depending on the final option and required approvals, the line could take 7 to 10 years to complete. The timeline underscores the urgency of beginning the process now as Toronto braces for explosive population and economic growth.

In addition to the transmission line, complementary solutions — such as rooftop solar, battery storage systems, and expanded energy efficiency programs — are also under consideration to support electricity resilience across the city.

The project is a key pillar of Ontario’s forthcoming Integrated Energy Plan, which is expected to outline a comprehensive vision for the province’s energy future, including clean energy growth and expanded export potential.

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