Ontario’s energy infrastructure is gearing up for another major upgrade. The provincial government has officially authorized Hydro One to develop a new high-voltage transmission line between Bowmanville and the Greater Toronto Area (GTA). With rising electricity demand, nuclear expansion plans, and future industrial growth on the horizon, this new project is expected to play a huge role in strengthening the province’s power grid. The project also highlights continued partnerships with First Nations, which is nice to see, though some details are still evolving.
1. Overview of the New Transmission Line
The Ontario government has authorized Hydro One to begin development of a new 500-kV double-circuit transmission line. This major infrastructure project will connect Bowmanville to the Greater Toronto Area and is expected to significantly increase electricity capacity.
2. Government Direction and Licensing
Energy and Mines Minister Stephen Lecce formally directed the Ontario Energy Board to amend Hydro One’s transmission licence, clearing the way for construction and planning activities.
3. Route Options and Technical Specs
The line will run from the Bowmanville Switching Station to one of the following terminal stations:
- Parkway TS
- Claireville TS
- Cherrywood TS
The project also includes expansions and upgrades to station facilities along the route.
4. Projected In-Service Timeline
The new transmission line is expected to be operational in the early 2030s, supporting both regional and province-wide power requirements.
5. Additional Priority Transmission Projects
Alongside the Bowmanville line, the province has issued priority status to two more Hydro One projects:
a. Orangeville to Essa Reconductoring (230 kV)
Expected in service: 2027
b. Lauzon to Lakeshore New Transmission Line (230 kV)
Expected in service: 2032
These upgrades aim to boost reliability and meet fast-growing electricity demand in southern Ontario.
6. Hydro One’s Partnership with First Nations
Hydro One confirmed that First Nations communities in proximity to the project will be full partners. They will also have the option to acquire a 50% equity stake in the transmission line portion of the project — a structure similar to other major Ontario grid developments.
7. Bowmanville Switching Station Expansion
The transmission line announcement comes shortly after AtkinsRéalis Group Inc. was selected for a multi-year owner’s engineer mandate. Their role includes the expansion of the Bowmanville Switching Station, located near the Darlington Nuclear Generating Station.
8. Role of Small Modular Reactors (SMRs)
The expanded station will enable grid connection for four planned Small Modular Reactors (SMRs) being built by Ontario Power Generation at the Darlington New Nuclear Project site. These SMRs are expected to become a major part of Ontario’s clean-energy mix.
9. Impact on Ontario’s Energy Future
This new infrastructure will help Ontario:
- Support electrification and industrial growth
- Ensure reliable power delivery to the GTA
- Prepare for future nuclear-based supply
- Modernize aging transmission assets
10. Key Benefits to the GTA and Beyond
The project will:
• Increase transmission capacity
• Improve grid reliability
• Boost economic development
• Support clean-energy expansion
11. Challenges and Considerations
Although the project is progressing, details such as exact routing, environmental assessments, and community consultations must still be finalized. There may be small adjustments as planning unfolds.