Ontario Focused on Economy by Approving New Toronto Transmission Line

TORONTO – The Ontario government is starting 2026 with a focus on driving growth and creating jobs by approving the Independent Electricity System Operator’s (IESO) recommendation to build a new underwater electricity transmission line from near the Darlington Nuclear Generating Station to the downtown core and eastern portion of the City of Toronto. This first-of-its-kind high-voltage underwater transmission line in Ontario ensures the province will keep up with growth as electricity demand in Toronto is expected to double by 2050. Ontario’s plan will deliver up to 900 megawatts (MW) of clean, reliable power, securing the electricity needed to fuel housing, transit, and economic growth. This project aligns with Ontario’s record investments to upgrade and expand nuclear generating capacity on-time and on-budget, including the Darlington Nuclear Refurbishment Project and the construction of the first small modular reactors in the G7 at Darlington New Nuclear Project.

“As we start 2026, we are focused on strengthening Ontario’s economy and creating jobs,” said Stephen Lecce, Minister of Energy and Mines and MPP for King--Vaughan. “Without a new transmission line, Toronto would have to turn down job-creating investments and reduce housing, which is simply unacceptable. We are thinking ahead and building for the future by approving a new transmission line that will enable 285,000 new homes, power new businesses, and create thousands of jobs. We are also initiating the first IESO-led competitive transmission procurement to reduce costs and maximize benefits for families.”

As Toronto’s electricity system approaches its capacity limit, at the same time the city is experiencing unprecedented growth, with the highest demand in the downtown core. Currently, the City of Toronto is supplied by two transmission lines, one from the west at Manby Transmission Station (TS) and one from the east at Leaside TS. These pathways will begin to reach their capacity in the 2030s, demonstrating a clear need for additional transmission infrastructure. Ontario’s plan to build a third transmission line will meet growing demand by delivering 900 MW of additional power, equivalent to all the power generated from three small modular reactors, or power for 900,000 new homes.

“Toronto is the fastest-growing city in North America, and that growth means we need more power to fuel our homes, transit, and businesses,” said Olivia Chow, Mayor of Toronto. “I want to applaud the Ontario government for moving forward with this first-of-its-kind underwater transmission line. It’s an exciting example of the province and city working together to build resilient, clean energy infrastructure that keeps costs down, supports good-paying jobs, and powers the projects that will shape Toronto’s future. We’re committed to creating an affordable and caring city that delivers for Torontonians.”

To keep costs affordable, the government is proposing the IESO launch a competitive procurement process to select a transmitter, which will be informed by a consultation on the procurement design. This approach will drive value for ratepayers while accelerating construction and creating opportunities for Indigenous participation and good-paying jobs across the province.

An underwater third transmission line will build system resilience by providing an option that is less vulnerable to extreme weather events such as flooding or ice storms, instances that have previously resulted in lost electricity supply and $100–200 million in costs and lost productivity. The underwater cable will also deliver more capacity than any other option and meet the system needs beyond 2044, reducing the need for additional, costly upgrades and expansions. The third line will also alleviate strain on the bulk power system by avoiding bulk system reinforcements elsewhere in the GTA which could result in an estimated preliminary savings of $100–$300 million.

The development, construction and commissioning of a third transmission line to Toronto could take between seven to 10 years to complete, underscoring the importance of acting now to further Ontario’s clean energy advantage, ensure reliability and position the province and city to put shovels in the ground sooner on critical infrastructure projects. The IESO’s recommendation follows extensive technical analysis of multiple options, prioritizing routes that minimize land-use impacts by leveraging existing corridors, underground infrastructure and pathways. The proposal is detailed in the 2025 Toronto Integrated Regional Resource Plan.

Expanding transmission infrastructure is a key pillar of Energy for Generations, the province’s first-ever integrated energy plan to ensure Ontario has the reliable, affordable power it needs to power new homes and drive economic growth. The government’s integrated approach and record investments in energy infrastructure are providing the certainty needed for Indigenous communities, municipalities, businesses and industry partners to invest confidently in Ontario’s future. With a clear path forward, the plan is not only meeting the demands of today, but it is protecting jobs, supporting workers and powering economic growth for generations to come.

Quick Facts

• High-voltage underwater transmission lines have been used in other Canadian jurisdictions such as Newfoundland and Labrador, Nova Scotia, and Prince Edward Island.

• 900 MW is equivalent to powering 900,000 homes.

• Peak electricity demand in Toronto is 4,700 megawatts, which is approximately 20 per cent of peak demand for all of Ontario. According to Ontario’s Independent Electricity System Operator, after 20 years of flat electricity demand in the city, Toronto’s peak demand is expected to roughly double by 2050, which includes:

• Building New Homes: Energy to power at least 285,000 new homes in Toronto as part of the city’s 10-year housing target. That includes new communities at Downsview, Port Lands, East Harbour and Golden Mile.

• Economic growth: Toronto is an attractive investment destination and serves as a provincially and nationally significant centre for job creation and economic growth.

• Transit expansion: GO Transit Electrification and the new Ontario Line alone are anticipated to add an additional 100 megawatts of energy demand to Toronto’s system.

• Electrification: Increased adoption of electric vehicles.

• The Integrated Regional Resource Plan (IRRP) for Toronto, developed by the IESO, is part of a broader effort to anticipate and plan for localized electricity needs across Ontario.

Quotes

"Our government made a commitment to Protect Ontario, and this project firmly advances our commitment. By enabling the development of more homes in one of Ontario’s fastest-growing regions, we are bringing the dream of homeownership within reach for more families and keeping more workers on the job. Innovative approaches to managing and preparing for growth such as this are how our government intends to continue building communities where residents can thrive."

- Rob Flack

Minister of Municipal Affairs and Housing

"Building out transmission infrastructure is a key piece of our long-term integrated energy plan to meet the rapidly growing electricity demand in Ontario. This investment will not only enhance Ontario’s energy self-reliance and grid security, but will create good-paying jobs, keep rates competitive for industries, and support foundational projects in Toronto for decades to come."

- Sam Oosterhoff

Associate Minister of Energy-Intensive Industries

"This is a smart and necessary step to build economic resiliency and growth for Toronto and Ontario. The age of electrification is dawning and demand for power is rising fast. A new transmission line will give businesses more certainty to invest, expand, and boost productivity in our core and across the region, while strengthening the grid and protecting scarce employment lands. It’s a clear signal that Ontario is planning ahead and building the infrastructure our competitiveness depends on."

- Giles Gherson

President and CEO, Toronto Region Board of Trade.

"As Toronto's energy needs expand, strengthening our city's access to safe, reliable and resilient electricity is essential to supporting our shared future and fostering growth opportunities in our community and economy. Toronto Hydro is supportive of the ongoing development of the Third Line, and today’s update from the Province marks an important moment in growing the connection between our provincial energy system and the local homes and businesses that rely on it. By expanding our region's transmission capacity, we’re investing in a bright, sustainable future for all Torontonians."

- Jana Mosley

President & CEO, Toronto Hydro Corporation

"Toronto’s demand for electricity is increasing significantly. A new underwater transmission line into Toronto will ensure electricity remains reliable for residents and businesses while enabling economic growth. The IESO has engaged with transmitters, Indigenous communities and other interested stakeholders to inform our recommendation for the underwater line which will be procured through a competitive process. This approach will ensure we provide the best value to ratepayers while supplying Toronto’s energy needs for generations to come."

- Lesley Gallinger

President and CEO, Independent Electricity System Operator

"The Ontario Energy Association commends the Government of Ontario for its many ongoing proactive investments in Ontario’s electricity grid infrastructure including the planned third transmission line into Toronto. The new transmission line will increase provincial system capacity to meet expected housing and economic growth in Toronto and enhance the resiliency of the provincial grid. In addition, the development of this new infrastructure will help Ontario companies and supply chains."

- Vince Brescia

President & CEO, Ontario Energy Association

"The Building Industry and Land Development Association (BILD) and its members are very pleased to support today’s announcement by the Ontario government on the decision to approve a new underwater electricity transmission line providing a connection from near the Darlington Nuclear Generating Station directly to downtown Toronto. Access to adequate housing supportive infrastructure, including sufficient electrification capacity, is a key barrier to providing the housing supply needed, not only in the GTA, but also across the province. Approval of the Independent Electricity System Operator’s (IESO) recommendation for this new transmission capacity is critical to ensuring the City of Toronto can continue to add new housing to meet the demands of a growing and vibrant City."

- Dave Wilkes

President & CEO, Building Industry and Land Development Association

"Reliable and affordable energy supply is critical to supporting growth including within the City of Toronto. New and existing homes require energy they can count on and today’s announcement with respect to a new underwater transmission line is further demonstration of the Ontario Government’s commitment to our future energy needs which includes supporting housing supply. Premier Doug Ford and Minister Stephen Lecce are to be commended for their ongoing efforts in this regard."

- Richard Lyall

President, Residential Construction Council of Ontario

"Housing supply depends on infrastructure keeping pace with growth. Communities across Ontario are approaching real electricity capacity constraints, and without new transmission investments, the ability to deliver housing at scale will be compromised. Advancing projects like this now is a critical step to ensuring approved housing can actually be built, supporting affordability and enabling growth in communities across the province."

- Scott Andison

CEO, Ontario Home Builders Association

"The Ontario Chamber has long advocated for modernizing Ontario’s energy infrastructure through new transmission investments. This project is a clear step in that direction, strengthening energy certainty, supporting growth in housing and transit, and helping deliver value for ratepayers."

- Vincent Caron

Vice President of Policy, Ontario Chamber of Commerce

"EDCO applauds the Ontario government’s approval of the Independent Electricity System Operator’s (IESO) recommendation to build a new underwater transmission line. This plan is a game-changer for economic development across the province. Reliable, clean power is essential for attracting investment, supporting housing and transit projects, and enabling the growth of businesses in every community. By securing Toronto’s future as a global economic hub and creating good-paying jobs and opportunities for suppliers and service providers throughout Ontario, this initiative delivers benefits far beyond the city’s core. For EDCO members, it provides the certainty needed for long-term planning and the confidence to market their communities to investors who demand dependable infrastructure. Strengthening our energy system sends a clear signal that Ontario is committed to growth, innovation, and prosperity for generations to come."

- Stephanie Crilly

Executive Director, Economic Developers Council of Ontario (EDCO)

Additional Resources

2025 Toronto Integrated Regional Resource Plan (IRRP)

Ontario and Toronto Planning for the City’s Growing Electricity Needs

Energy for Generations

MEDIA CONTACT                                                                                              

Stephen Lecce, MPP for King—Vaughan

Constituency Office

Tel.: 647-560-9700        

Email:

Stephen.Lecce@pc.ola.org