Ontario has approved a $1.5 billion underwater electricity transmission line to reinforce the reliability of Toronto’s power grid amid a surge in demand. The transmission line runs underwater from near the Darlington Nuclear Generating Station to Toronto’s downtown core and eastern waterfront. It delivers up to 900 megawatts using HVDC technology, enough to power roughly 900,000 homes.
Approval and Timeline
Energy Minister Stephen Lecce approved the plan on January 7, 2026, following a recommendation from the Independent Electricity System Operator (IESO) in its 2025 Toronto Integrated Regional Resource Plan. In 2026, the IESO will launch a competitive procurement process to select a transmitter. The transmitter will be chosen in 2027. Development, construction, and commissioning will then follow, taking seven to 10 years, with an in-service date targeted for 2037 or sooner.
Key Benefits
The underwater line boosts grid resilience against extreme weather, supports 285,000 new homes and businesses, avoids $100-300 million in other reinforcements, integrates clean energy, and provides black-start capability for faster outage recovery. Minister Lecce said the line safeguards investments and housing against power shortages. IESO CEO Gallinger noted its competitive and consultative approach, including Indigenous engagement. Mayor Chow praised the partnership for boosting infrastructure and jobs.
Procurement and Consultation
The process prioritizes transmitters with underwater line experience and Indigenous engagement expertise, possibly via partnerships. Evaluation criteria include Indigenous economic participation, such as equity and jobs, as well as Ontario business incentives. A public consultation on the Environmental Registry of Ontario runs until February 21, 2026, and includes a Duty to Consult for Indigenous communities. Contracts will enforce timelines, cost controls, and environmental approvals.
This underwater transmission line positions Toronto for growth amid North America’s fastest urban expansion. A reliable power supply now supports housing and the economy without land disruptions.
Image Credit – cbc.ca
