Could underground power lines have kept lights on after ice storm?

Watch the video above: Should more power lines be moved underground? Cindy Pom reports. 

TORONTO – Could underground hydro lines have kept the lights on for the hundreds of thousands of people whose power was knocked out following last week’s ice storm?

At the height of the outages, 300,000 Toronto Hydro customers were left in the dark as trees weighed down by ice fell onto overhead power lines that stretch across much of the city.

But the some of the lights remained on in areas where there were underground lines. So why aren’t they more prevalent in the city?

There are a few reasons, according to Toronto Hydro spokesperson Tanya Bruckmueller, including inherited infrastructure.

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When the cities of Etobicoke, North York, Scarborough and Toronto amalgamated, so did their utilities. As a result, Toronto Hydro inherited a vast swath of overhead lines in older neighbourhoods. To convert overhead lines to underground would carry a huge cost, she said.

“It’s probably about seven to 10 times the cost of overhead infrastructure – which would be funded through rates obviously,” Bruckmueller said. “So the ratepayers would have to pay for that.”

New neighbourhoods generally get underground lines, she added.

However, Harry Orton, an independent hydro consultant based in Vancouver, said over their lifetime the cost of underground lines could be equivalent to overhead lines.

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While Orton said he is generally in favour of underground lines – he’s convinced they are much more aesthetically pleasing than overhead lines – he admitted they aren’t perfect and utilities should weigh the pros and cons of the two options on a project by project basis.

Underground wires are also susceptible to the weather; specifically flooding. A July rain storm dropped an unprecedented 126 mm of rain on Toronto which led to flooding across the city and knocked out power to a GO Train, trapping close to 1,000 people onboard.

But it only took Toronto Hydro approximately four days to bring power back to most of the city after the flood, due in part to the “hardening” done to some of the underground infrastructure.

Orton agrees underground systems can be damaged in a flood.  “In many flood situations you find that there is very little damage done to the equipment that is underground,” he said.

Repairing underground lines can take longer than overhead lines, Bruckmueller said. The former forces crews to spend time finding the fault, before digging it up and repairing it, while faults overhead are out in the open.

“We have a number of areas in the city that see more than normal outages in terms of frequency and duration and the reason for that is that everything is underground, so our crews have to find where the problem is underground without digging the entire cable up,” she explained. “And when they actually do find the problem, they’ll actually have to excavate the area where they can and do the repairs to the patch.”

Toronto’s city council is planning a special meeting for Friday to examine infrastructure readiness and the city’s response to the ice storm. Ahead of that meeting however, councillor Joe Mihevc (Ward 21) published an op-ed in which he called for Toronto Hydro to bury its power lines.

“Toronto needs to examine burying its hydro wires on a multi-year plan. One can appreciate Toronto Hydro’s reluctance for financial reasons,” Mihevc wrote in the Toronto Star. “However, it is now clear that the cost of these kinds of storms needs to be a part of the calculation.”

– With files from Cindy Pom