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Toronto Hydro employees remove tree branches from downed hydro wires before doing repairs in the area in Toronto on December 23, 2013. Thousands of residents are still without power and tree limbs still litter some thoroughfares following the ice storm on Dec. 22nd.Peter Power/The Globe and Mail

Faced with severe weather events such as this week's ice storm in Ontario, Canada's electrical utilities are looking at spending billions to make their power systems less vulnerable.

But those efforts will have to overcome resistance from energy regulators and consumers who worry about rising costs and threats to shade trees in the cities.

In the aftermath of the 1998 ice storm in Quebec and Eastern Ontario, power utilities hardened their systems by re-engineering transmission towers, increasing their tree pruning efforts to keep ice-laden limbs away from lines and striking mutual assistance agreements with neighbouring jurisdictions to ensure crews are available for cleanup.

Now, they are working with such municipalities as Toronto to assess the looming threat of climate change, and how to lessen their vulnerability in the expectation of an increasing frequency of severe weather events. The greater resiliency will come at a cost, though, as the blackout in Southern Ontario amply illustrated that vulnerability has its price, too.

"The key question is: What is in our expectation of reliability in the long run? And what is a reasonable cost to beat to have a major failure every 10 years, or every 20 years or every 100 years?" said Jim Burpee, president of the Canadian Electricity Association. "The assumption is we're going to see a wider variety of weather, whether it is ice events or tornadoes or the rainfall we had that caused so much flooding" in Toronto last summer.

But Mr. Burpee said it can be difficult to get the Ontario Energy Board – or energy regulators in other provinces – to approve the rate hikes that are required to pay for the investment. Toronto Hydro had to defend its planned $232-million transformer station – to supply downtown Toronto – from critics who said the station was not needed, though the existence of such a station would have helped keep the lights on in areas of the city after last weekend's ice storm.

However, Jack Gibbons, of Ontario's Clean Air Alliance, said utilities typically "promote 1950s supply-side solutions" rather than smaller-scale, localized combined heat and power plants that can limit the need for lengthy distribution lines.

With the expectation of increasing frequency in severe weather, utilities are looking at recommendations to increase the strength of their transmission and distribution lines; to ensure underground systems are flood-proof; to bury overhead wires; and to employ a small army of workers to keep trees as far away as possible from wires.

In partnership with the city, Toronto Hydro has already run a pilot study looking at the vulnerabilities of the system, including the prevalence of overhead wires versus buried cables, the use of wooden poles versus concrete ones, and the various types of transformers. And last month, Toronto City Council approved a staff report on the need to address the vulnerability of its infrastructure to the threat of climate change.

But the costs of remediation can be staggering.

New Jersey's electricity and gas utility, PSE&G, last summer unveiled a $3.9-billion plan to strengthen its energy system in the aftermath of super-storm Sandy that ravaged the area last fall. Its plan – which has yet to be approved by regulators – would raise or relocate electricity-switching stations, strengthen power poles and replace aging underground gas mains. Consumer groups have attacked the New Jersey plan as extravagant and unnecessary.

Perhaps the best and most cost-efficient defence against ice storms is aggressive tree-pruning. "When you have a storm like this, the three greatest causes of outages are trees, trees and trees," said Mike Penstone, vice-president of network development for Hydro One, the provincially owned corporation that runs the transmission system and distributes power in rural communities. "Hydro One and all the other distribution companies in Ontario try to mitigate the effects of wind storms and ice storms through forestry practices, or vegetation management. But nobody likes to see a tree trimmed or cut, so clearances between trees and distribution lines are quite limited."

A more costly solution is to bury the power lines. In most newer suburban developments, power lines have been installed underground along with gas and water pipes. But while Toronto Hydro has a project to bury some of its lines, there is no consensus that the cost of doing so on a massive scale across dense urban centres would be worth the benefit.

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