Toronto Can Meet Future Power Needs Without Gas or Nuclear, New Analysis Shows

Over 50% of Toronto’s projected surge in electricity demand could be fulfilled cost-effectively within city limits using demand-side management, rooftop solar, and storage, concludes a new analysis by Environmental Defence Canada, produced as part of an effort to engage with Torontonians about the future of their power mix.

Critical consultations with Ontario’s Independent Electricity System Operator (IESO) are now under way to determine how Canada’s largest city and its surrounding regions will power themselves through the next decades. In a newly released [pdf] “high-level vision” for electricity planning, Environmental Defence concludes that more gas or nuclear power is not the answer. Senior program manager Aliénor Rougeot told The Energy Mix this is especially true after the Trump administration’s recent economic attacks on Canada, which highlight the risks of relying on fossil fuels imported from the United States.

Conservation, Rooftop Solar, Storage Suffice

Toronto currently consumes about 24 terawatt-hours (TWh) of electricity annually, with peak demand reaching 4,700 megawatts (MW) in 2023. Based on the IESO’s projections for 2035—6,300 MW in summer and 7,000 MW in winter—Environmental Defence estimates the city’s annual electricity use will rise to 34–37 TWh by then, an increase of 10–13 TWh from today.

Toronto could supply over 50% of this projected demand increase by 2035 through three key measures, the analysis suggests:

• Demand-response programs: Energy efficiency retrofits, smart thermostats, commercial and industrial flexibility programs, and EV load shifting could cut annual electricity use by 3.6 TWh.

• Rooftop solar expansion: Peppering photovoltaics on 50% of suitable rooftops could generate about 4.9 TWh per year. Toronto’s climate plan already pledges 100% rooftop coverage by 2050.

• Energy storage deployment: Maximizing utility-scale, residential, and thermal storage to 1,000 MW by 2035 would align with TransformTO’s 2,000 MW goal for 2050, even though a recent IESO resource planning video failed to mention storage at all.

On June 27, 2024, Toronto City Council requested [pdf] that the Portlands Energy Centre—a highly-polluting peaker gas plant located in the heart of the city—be effectively shuttered, only to be used in cases of extreme urgency. Its 550-MW capacity would be replaced by non-emitting electricity sources. Environmental Defence calculates that a combination of efficiency and conservation measures would more than cover the loss of the plant. 

Prioritize The Cheapest Sources

Ontario’s most affordable electricity sources in 2024 were utility-scale wind at $48/MWh and solar at $69/MWh, by IESO estimates. The analysis says those costs are expected [pdf] to fall further—potentially to $42/MWh for wind and $47/MWh for solar, based on a 2022 projection.

By comparison, the IESO pegged conventional nuclear at $140/MWh and small modular reactors at $155/MWh in 2024, Environmental Defence writes, and gas came in even higher, at $185/MWh.

Given the cost difference—and the long timelines for developing nuclear plants—it’s time to consider offshore wind on the Great Lakes, the analysis concludes. A 2008 report for the then Ontario Power Authority, whose operations were eventually folded into the IESO, estimated that 64 offshore wind farms on the lakes could generate 111–150 TWh of electricity per year.

The IESO found that energy efficiency measures are the cheapest option, costing just $20/MWh to save electricity rather than generating new supply. Rooftop solar would cost $157/MWh, dropping to $70/MWh by 2050, but the true costs should account for savings accrued by avoiding transmission costs, Environmental Defence states.

Energy storage is another cost-effective solution. “In Ontario’s latest capacity procurement round, storage projects that were awarded contracts came in at less than half the price of new gas plants,” the report recalls. The average weighted price of storage was $672/MW-day, compared to $1,681 for gas.

A Resilient, Independent Power System

Given anxieties around energy security, Donald Trump’s shifting policies should factor into Toronto’s power decisions, Rougeot told The Mix.

“Despite our efforts [to buy Canadian], there is one American product that is forced on Ontarians every day: fracked gas,” Rougeot said, noting that 70% of the gas used in Ontario in 2023 was imported from Pennsylvania or Ohio.

Energy efficiency and conservation provide “a natural partial solution” to any vulnerability, while also creating green jobs and lowering energy bills, Rougeot added.

Another solution to the problem is renewables plus storage. “The wind will blow and the sun will shine regardless of who is in the Oval Office, and that’s a major source of energy independence,” Rougeot said.

With consultations still under way, Environmental Defence is encouraging Torontonians and other stakeholders to share their input on its “conversation starter” proposal.

Cover photo:  Portlands Energy Centre, Toronto, Richard apple/Wikimedia Comm