Hot weather puts strain on hydro system; Power use, lightning cause blackouts


NFPA 70E Training

Our customized live online or in‑person group training can be delivered to your staff at your location.

  • Live Online
  • 6 hours Instructor-led
  • Group Training Available
Regular Price:
$199
Coupon Price:
$149
Reserve Your Seat Today
Ontario residents, trying to keep cool in the middle of an extreme heat alert, kept the megawatts flowing near record levels even as parts of Toronto suffered mini-blackouts.

Pockets of the city were blacked out because the demand for power caused some equipment to overheat and two transformers in North York were struck by lightning, Toronto Hydro said.

Some stores, restaurants and movie theatres were forced to close for more than two hours when the power went out in a section of Yorkdale Shopping Centre on Dufferin St. at Highway 401.

Toronto Hydro said transformers at Jane St. and Finch Ave. W. and Dufferin St. and Finch Ave. W. were struck by lightning around 6:30 p.m. The lights came back on in the mall just before 8 p.m.

In Scarborough, the area of Finch and Pharmacy Aves. also experienced a blackout.

A spokesperson for Toronto Hydro said the problems came from transformers that overheated and needed repair. There were no problems with generating power, she said.

There's no relief in sight from the heat, Day 12 of Ontario's second-longest June heat wave.

At 5 p.m., the Independent Electricity System Operator recorded 25,816 megawatts flowing down the wires, down from the record high of 26,157 on June 27.

Toronto's health department has declared an "extreme heat alert," meaning that vulnerable people could die without proper precautions.

Metro Hall and the former civic centres in East York, Etobicoke and North York were open to the public as emergency cooling centres.

Southern Ontario will get some relief from the heat wave June 30, when temperatures are expected to dip below 30C. On Canada Day, it will be 26C, with the trend continuing on July 2,3.

Another warm front will push in to raise temperatures as people head back to work July 4.

Long-range forecasters are predicting hot and dry weather through July and August.

Ontario's chief conservation officer, Peter Love, urged Ontarians to turn off the lights, raise the temperature on their air conditioners and try to use appliances after 8 p.m.

Ontario Premier Dalton McGuinty said his family air conditioner broke two weeks ago and he was told it wasn't worth fixing.

"So I had to get in line to buy a new one." he said.

Meanwhile, Ontario Power Generation won a permanent injunction against striking Society of Energy Professionals at Hydro One, the province's energy distributor.

Related News

UK must start construction of large-scale storage or fail to meet net zero targets.

UK Hydrogen Storage Caverns enable long-duration, low-carbon electricity balancing, storing surplus wind and solar power…
View more

'For now, we're not touching it': Quebec closes door on nuclear power

Quebec Energy Strategy focuses on hydropower, energy efficiency, and new dams as Hydro-Que9bec pursues Churchill…
View more

Sunrun and Tesla Unveil Texas Power Plant

Sunrun-Tesla Virtual Power Plant Texas leverages residential solar, Tesla Powerwall battery storage, and ERCOT demand…
View more

Expanding EV Charging Infrastructure in Calgary's Apartments and Condos

Calgary EV Charging for Apartments and Condos streamlines permitting for multi-unit dwellings, guiding condo boards…
View more

This Floating Hotel Will Generate Electricity By Rotating All Day

Floating Rotating Eco Hotel harnesses renewable energy via VAWTAU, recycles rainwater for greywater, and follows…
View more

Typical Ontario electricity bill set to increase nearly 2% as fixed pricing ends

Ontario Electricity Rates update: OEB sets time-of-use and tiered pricing for residential customers, with kWh…
View more

Sign Up for Electricity Forum’s Newsletter

Stay informed with our FREE Newsletter — get the latest news, breakthrough technologies, and expert insights, delivered straight to your inbox.

Electricity Today T&D Magazine Subscribe for FREE

Stay informed with the latest T&D policies and technologies.
  • Timely insights from industry experts
  • Practical solutions T&D engineers
  • Free access to every issue

Download the 2026 Electrical Training Catalog

Explore 50+ live, expert-led electrical training courses –

  • Interactive
  • Flexible
  • CEU-cerified