North America | June 9, 2025

Ontario begins major transmission line expansion

New transmission initiatives are key to Ontario’s upcoming Integrated Energy Plan, which aims to boost domestic reliability and unlock export opportunities.

 

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Canada, Ontario: The Ontario government has announced plans to construct two new electricity transmission lines and enhance two existing ones to address the province’s growing energy needs and support economic growth. This initiative marks one of the most significant transmission investments in Ontario’s history.

The Ministry of Energy and Mines stated that the initiative includes around 160 km of newly built and upgraded transmission lines to accommodate Ontario’s increasing electricity demands. This announcement comes on the heels of the government’s recent proposal for the most extensive nuclear expansion in the province’s history.

The new and upgraded lines are designed to supply electricity to manufacturing plants, greenhouse enterprises, and growing communities. Over the next 25 years, Ontario’s electricity demand is forecasted to increase by 75 %, with industrial consumption alone anticipated to climb by 40 % within the next five years.

To meet these emerging challenges, the province plans to consult on three key transmission initiatives:

  • A new transmission line linking Bowmanville to the Greater Toronto Area, designed to connect additional electricity generation in Eastern Ontario – including power from the Darlington small modular reactors – to the provincial grid;
  • A new line between Windsor and Lakeshore, intended to support the rising electricity demands of the Windsor-Essex region’s greenhouse and manufacturing industries;
  • An upgrade of the existing infrastructure between Orangeville and Barrie, aimed at enhancing system reliability and enabling continued economic growth in Central Ontario.

Additionally, the government expressed support for enhancing the transmission lines between Manby and Riverside Junction in Toronto, aiming to increase capacity and meet the growing electricity needs of the city’s west end and downtown core.

“Ontario is growing fast and so is our energy demand,” said Stephen Lecce, Minister of Energy and Mines. “That is why we are planning early and advancing approximately 160 km of new and upgraded transmission lines to connect people and businesses to the affordable, secure, reliable, and clean energy they will need in the years ahead. After announcing the largest nuclear expansion in Ontario history, we are building for the future by advancing one of the largest transmission expansions in Ontario history. This is part of Ontario’s long-term integrated plan for economic self-reliance.”

The government also reiterated its backing of Hydro One’s pledge to form 50-50 partnerships with Indigenous communities in the development of new large-scale transmission lines – an approach designed to foster economic reconciliation and deliver lasting advantages to the communities involved.

These transmission developments are part of Ontario’s forthcoming Integrated Energy Plan, expected later this month, which will present a broad strategy to ensure the province’s long-term energy security and support electricity exports to other regions.