Hydro poles in back alleys behind Fern Avenue in Roncesvalles on July 9, 2010.Jennifer Roberts
The explosion at a Kipling transformer station on Monday, which turned out the lights on 250,000 Torontonians, was a reminder that the city's power grid is in need of serious attention. Much of it was designed and built from the 1920s through the 1970s, and the tab to modernize it easily reaches into the billions. In the past six years, Toronto Hydro has increased its repair spending from $40-million to $275-million a year, jacking up rates to pay for it. Hydro One, which manages the transmission grid, is targeting creaky infrastructure as well.
Here are some of Toronto's most precarious power hot spots:
1) Manby Transformer Station: The site of Monday's explosion, when a circuit breaker dating to the 1970s (well within its lifespan) failed. All of the pre-amalgamation City of Toronto's high-voltage power arrives through just two stations - here, and in Leaside - so failures reach across downtown and midtown. Hydro One is replacing circuit breakers and transformers at these stations, hoping to stay ahead.
2) Midtown Power Corridor: Bringing power to a vast swath of the city's west end encompassing Roncesvalles, the Junction, West Queen West, Bloor-Lansdowne and the Annex, as well as a chunk of Rosedale, these 1950s-vintage high-voltage transmission lines are part of the power grid's backbone. Hydro One has singled them out as being in need of replacement.
3) Lakeshore Power Corridor: High-voltage lines usually last about 50 years, after which their insulation starts to degrade. The late-1950s Lakeshore lines - which service the downtown core and the west end and make up part of the grid's backbone, are nearing the end of their lives. Hydro One is planning to replace them.
4) Northeast Scarborough (Morningside/Finch), North York: When these suburbs were built in the 1970s, the cables were buried without being enclosed in a vault, as most underground cables are. High-tech insulation was supposed to protect the cables and save money. But by 2005, deteriorating, hard-to-fix wires were causing outages across the city's northeast. Toronto Hydro is now replacing them.
5) Dufferin substation. Substations take high-voltage power and distribute it to the neighbourhood. The Dufferin substation handles roughly St. Clair to Queen, and Spadina to Jane. In the winter of 2009, a flood at this Toronto Hydro substation caused a midtown blackout. Weak connections to other substations meant that Hydro couldn't redistribute power after the flood; now it is working to build stronger links.
6) Forest Hill, High Park: From the 1920s to the 1940s, hydro poles in these neighbourhoods were built in back alleys, instead of out front. Since then, trees have grown around them, making repairs difficult (and outages lengthy) since bucket trucks can't get in.
7) Queen West/Liberty Village: The west end has some of Toronto's oldest infrastructure, which leads to reliability problems. There have been equipment upgrades over the years, but the power-grid design in this area dates back to 1911 - specs that are insufficient for the power-hungry Toronto of 2010. An overhaul is under way.
Special to The Globe and Mail