Subway passengers leave a darkened St. Andrew Station in Toronto after the blackout on Mon., July 5.
Hydro officials say the system that caught fire and caused a extensive power outage on Monday in Toronto was built to withstand the increased demands for power that came on the hottest day of the year.
The two-hour outage, which lasted almost four for some, was spotty but stole 920 megawatts of power from 250,000 customers in the city's downtown and west end. Traffic ground to a halt as commuters leapt out of their vehicles to direct cars while they waited for police. Subway service shut down in part of the city. Towers in the financial district closed as workers trundled down flights and flights of stairs to the exits.
While one can be quick to blame churning air conditioners for sucking up about 24,500 megawatts, more than the expected amount, from the grid, all of the chaos traced back to a fire in one breaker at a west-end transformer station belonging to the province's Hydro One.
It's a breaker in a system that shouldn't bend to the heavy demands of Toronto's consumers, its operators say.
"It is designed to operate in extreme heat in the summer and extreme cold in the winter," said Hydro One spokesperson Danièle Gauvin, adding that the machines are inspected regularly. "Those kinds of pressures on the lines are built in by the engineers."
Hydro One workers investigated late into the evening but had yet to determine what started the fire at the A.W. Manby transformer station at 850 Kipling Ave.
At 4:42 p.m., nearby residents heard a number of explosions popping from the 230 kilovolt line that feeds power to much of the city's downtown.
"The first one was a bit quieter, then in a split second there was a huge explosion," said Ivan Petrovski, a motorcycle mechanic working in his repair shop directly across from the station. "It was like, ka-kow!"
Others in the area reported feeling a big boom before their homes went dark.
As the outage hit the downtown core, people had to quickly adapt. The subway shut down between Jane Street and Kipling Avenue, forcing shuttle buses to carry the rush-hour load. The rest of the subway system was working, albeit without full lighting. The Financial District lost all power, but the Toronto Stock Exchange, First Canadian Place and other financial operations were rescued by emergency generators.
Kevin Wilkinson, a 29-year-old research associate with Northland Capital Partners Inc. who was in First Canadian Place, said there was a lot of frustration as employees lost valuable work. "It was after market hours closed, so it wasn't the worst thing in the world," he said.
While there were no injuries reported in the outage (and hospitals were largely unaffected), firefighters were hard at work rescuing people trapped in elevators across the affected parts of downtown.
A firefighter at downtown condominium building 10 Navy Wharf said several people were taken out of two of the building's four elevators while the power was out. That building was his third stop. "There are people stuck everywhere," he said.
At about 6:40 p.m., power returned to the downtown core.
At about 7:50 p.m., Toronto Hydro was urging the approximately 48,000 or so customers still without power to turn off their air conditioners so they wouldn't overload the grid as power slowly returned.
By 8:25 p.m., the lights were back on for everyone in the entire region, stretching from Highway 401 to Lake Ontario and into Etobicoke.
The power outage hit on the hottest day since June, 2008 - the second day of a heat wave Environment Canada expects to continue through Friday. Temperatures crept above 34 C, although the humidity made it feel closer to 43.
Toronto's medical officer of health issued an extreme heat alert in the morning as temperatures crept close to 30 C as early as 8 a.m. In addition to issuing a heat advisory, Toronto Public Health upgraded their warning to "extreme" on Monday, and Environment Canada issued a smog advisory for the city and other areas of Ontario.
The demand for power was about 10 per cent higher than last Monday, when temperatures were nearly as high - it was 34.5 with the humidex - said Alexandra Campbell, spokesperson for the Independent Electricity System Operator, which manages the reliability of Ontario's power grid. Last Monday, the demand for power was 21,400 megawatts. The standing record for power consumption in Ontario is 27,005 megawatts on Aug. 1, 2006.
She said it's doubtful the power outage was related to an exceeding demand for power.
"It was operating well within its limits," she said. "It was likely a coincidence."
With reports from Anthony Reinhart, Anna Mehler Paperny, Ann Hui, Iain Marlow and Boyd Erman.