Powering Toronto’s Next Wave: How the Third Transmission Line Will Shape the City’s Construction Future

Toronto is entering a new phase of transformation, one defined not only by cranes in the skyline but by the invisible infrastructure powering everything beneath it. As the city races to meet its housing, transit, and electrification goals, the Ontario government and the Independent Electricity System Operator (IESO) have announced plans for a third transmission line into downtown Toronto.

It may sound technical, but for developers, contractors, and construction managers, this is game-changing news. The availability, reliability, and cost of electrical infrastructure will directly influence how we design, plan, and deliver the city’s next generation of buildings.

⚡ Why Toronto Needs a Third Transmission Line

Toronto’s two existing transmission lines, the Leaside and Manby corridors, currently deliver almost all of the electricity powering downtown’s homes, offices, transit systems, and high-density developments. These lines have served the city for decades, but they’re reaching their limit.

According to the IESO, demand for electricity in the Greater Toronto Area will nearly double by 2050, fuelled by rapid population growth, transit electrification, and the shift away from fossil fuels. As new housing and infrastructure projects emerge, particularly in high-demand areas like the East Harbour redevelopment, Port Lands, and along the Ontario Line, the city’s power grid is facing unprecedented pressure.

Without new transmission infrastructure, Toronto risks bottlenecks in power supply, which could delay or even halt construction timelines for new developments.

This is where the new third transmission line comes in. Its goal is to increase electrical capacity and ensure reliable power delivery to support both residential and commercial growth across the downtown core.

🏗️ What This Means for Developers and Builders

For construction professionals, this new development isn’t just background news, it’s a signal to adapt now.

The third transmission line reinforces a simple reality: electrical infrastructure is now a front-end priority, not a finishing detail. Developers breaking ground today must plan for a future where every project is electrified, from heating and cooling to parking and power storage.

Here’s how this shift impacts the construction industry:

1. Electrification is the new baseline

   The City of Toronto’s Green Standard and federal climate policies are moving rapidly toward banning fossil-fuel heating systems in new developments. By 2028, new gas-fired systems will effectively be phased out. That means all-electric systems, such as heat pumps, geothermal loops, and smart grids, will soon dominate new construction.

   As these technologies become standard, the demand for high-capacity electrical infrastructure will rise dramatically, and so will the importance of coordination between developers, engineers, and utility providers.

2. Planning for electrical capacity early

   Gone are the days when electrical design came after structural and mechanical. Today, utility coordination needs to start at the feasibility stage.

   Many developers underestimate the timeline required for Hydro One or Toronto Hydro to review, approve, and upgrade connections. These approvals can take months or even years, depending on location, capacity needs, and city infrastructure readiness.

   Starting early can mean the difference between a seamless project and a year-long delay waiting for power.

3. Construction sequencing will evolve

   As projects grow more complex, the traditional build sequence must adjust to accommodate early infrastructure work.Builders now need to:

   • Coordinate trenching and conduit work well before above-ground construction begins.

   • Sequence substation and transformer installations to align with mechanical milestones.

   • Integrate electrical commissioning earlier in the schedule.

   Failing to do so could stall a project at the occupancy stage, when everything looks complete but power delivery is still pending.

4. Cost and schedule certainty depend on utility alignment

   Utility delays can quietly erode profit margins. Aligning project schedules with utility timelines helps control risk and ensure delivery.Construction managers who proactively integrate electrical utility milestones into master schedules are now at a strategic advantage.

   
   

🔋 Toronto’s Electrification Push and Industry Implications

The electrification movement extends far beyond individual developments.

The City of Toronto and the Province of Ontario are both investing heavily in transit electrification, such as the Eglinton Crosstown, Ontario Line, and the electrification of GO Transit. Each of these projects adds strain to the regional grid, and opportunities for collaboration between private and public sector builders.

On the housing front, the Toronto Green Standard continues to push developers toward Tier 3 and Tier 4 performance levels, requiring highly efficient, low-carbon systems. This means new construction projects must be designed, built, and powered differently.

Together, these forces, sustainability, infrastructure, and policy, are converging to reshape Toronto’s entire building landscape.

💡 How RIISE Building Is Supporting the Shift

At RIISE Building, we view infrastructure readiness as a cornerstone of successful construction management. Our approach integrates utility coordination and energy planning from day one.

We work alongside developers, architects, and engineers to:

• Evaluate electrical demand and capacity during the pre-construction phase.

• Build realistic schedules that account for Hydro approvals and service installations.

• Coordinate sequencing between utility contractors and base-building trades.

• Recommend electrification-friendly systems and building designs that align with evolving regulations.

Our goal is to help clients stay ahead of the curve — building smarter, safer, and faster in a city that’s rapidly transforming its energy landscape.

🏙️ The Bigger Picture: Power as a Pillar of Urban Growth

The third transmission line isn’t just a new piece of hardware in Toronto’s electrical grid. It represents a new era of collaboration between builders, policymakers, and city planners, an acknowledgment that sustainable growth depends on resilient energy systems.

For the construction industry, this moment is both a challenge and an opportunity. The demand for electrification-ready infrastructure will create new partnerships, new technologies, and new ways of building.

Those who plan for it today will lead the projects that define Toronto’s skyline tomorrow.

Conclusion

Toronto’s next chapter will be powered not just by vision, but by voltage. The city’s third transmission line is more than an energy upgrade, it’s a catalyst for change in how we design, plan, and deliver the built environment.

For developers and construction professionals, now is the time to take power planning seriously. It’s no longer just a utility, it’s the backbone of future-ready development.

Ready to future-proof your next project?Contact RIISE Building to discuss integrated strategies for electrification, utility coordination, and power infrastructure planning in Toronto’s evolving construction landscape.

Phone: 647 695 2025

Email: info@riisebuilding.ca