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


Substation Relay Protection Training

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

  • Live Online
  • 12 hours Instructor-led
  • Group Training Available
Regular Price:
$699
Coupon Price:
$599
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

B.C.'s Green Energy Ambitions Face Power Supply Challenges

British Columbia Green Grid Constraints underscore BC Hydro's rising imports, peak demand, electrification, hydroelectric variability,…
View more

Nova Scotia can't order electric utility to lower power rates, minister says

Nova Scotia Power Rate Regulation explains how the privately owned utility is governed by the…
View more

RBC agrees to buy electricity from new southern Alberta solar power farm project

RBC Renewable Energy PPA supports a 39 MW Alberta solar project, with Bullfrog Power and…
View more

Washington Australia announces $600 electricity bill bonus for every household

WA $600 Electricity Credit supports households with power bills as a budget stimulus, delivering an…
View more

Electricity blackouts spark protests in Iranian cities

Iran Power Outage Protests surge as electricity blackouts, drought, and a looming heat wave spark…
View more

Alberta's Rising Electricity Prices

Alberta Last-Resort Power Rate Reform outlines consumer protection against market volatility, price spikes, and wholesale…
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