Explainer: Where do hydro poles come from?

A week after the devastating storm in southern Ontario and Quebec, communities in the affected regions are still reeling from the damage, with some residents going eights days and counting without power.

Hydro One, which services rural Ontario and is the largest utility company in the province, says 1,900 poles were damaged in the storm. Officials from Hydro Quebec have said that 500 poles in the province need replacing. And in the nation's capital, the storm damaged 300 poles, according to Hydro Ottawa.

Replacement poles will have to be sourced from somewhere, and utility companies typically rely on two different types of poles that support the overhead powerlines that deliver electricity to our communities.

WOOD VS. COMPOSITE POLES

Utility agencies typically have a mix of hydro poles made from wood as well as poles made of composite materials. Hydro One says it sources its wood poles from Stella Jones, an Ontario-based supplier, while Hydro Ottawa sources the vast majority of its poles from cedar and pine trees grown in Western Canada.

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"These poles are prized throughout North America for their balanced characteristics in durability, longevity and cost-effectiveness," Josée Larocque, manager of media and public affairs at Hydro Ottawa, told CTVNews.ca in an email Friday.

Utility companies have relied on poles made of wood for nearly two centuries, as it's a material with low conductivity and a low tendency to expand due to heat. Wood poles are also a green choice, as they can easily be recycled.

But in ditches, rugged terrain and wet and swampy areas that pose a structural challenge for wood poles, utility companies opt for composite poles, made from fibreglass and coated with resin and UV protection. Hydro Ottawa says its composite poles are manufactured in Ontario and can last up to 80 years, twice as long as wood poles.

"They also have a high strength-to-weight ratio, meaning they can be used in areas that may not be able to support a wooden pole … and they are resistant to both rot and woodpecker damage," Larocque said.

Hydro One says it typically keeps a supply of poles and other infrastructure items to prepare for adverse weather events, but the severity of last weekend's storm meant that the agency had to source additional supplies quickly.

"We work with many great partners who have stepped up to provide us with the products we need to get customers in affected areas restored. Our suppliers played a big part in our ability to restore power to the large majority of customers so quickly and we want to thank them for all they have done and continue to do," Hydro One spokesperson Richard Francella said in an email statement to CTVNews.ca on Friday.

THE NEED FOR RESILIENT INFRASTRUCTURE

With scientists warning that storms like the one seen last weekend are only going to become stronger, longer and more frequent thanks to the effects of climate change, questions have been raised over whether existing electric grid infrastructure is prepared.

"The grid that we've designed for today, we used the last 100 years' worth of data," electrical infrastructure expert Andrew Phillips told CTVNews.ca in a video interview Thursday. "Unfortunately, because of climate change, the past is not a good predictor of the future."

But there are alternatives to the currently used wood and composite poles that could be more resilient to storms. Phillips, who is the vice-president of transmission and distribution infrastructure at the Charlotte, N.C.-based Electric Power Research Institute (EPRI), points out that in Florida, which sees tropical storms or hurricanes on an annual basis, utility poles are typically made of concrete or steel.

These poles can withstand significantly higher wind speeds compared to wood poles, but Phillips says that they're much heavier, more expensive and more difficult to install and repair.

Utility companies in many European and Asian countries have chosen to bury their powerlines underground, but this option also comes with downsides relating to cost and repair.

"It's expensive to do, but of course … it also has the negative that if a failure does happen, it can take a long, long time to recover," Phillips said.

But Phillips says we shouldn't write off wood poles completely, given that wood is a renewable resource with a much smaller carbon footprint compared to concrete, steel or composite options.

"Concrete poles, steel poles and even composite poles all have a carbon footprint … while wood poles are kind of carbon neutral, because they grew in the ground as trees. So, there's a push a little bit in Europe to go back to the wood poles because of the carbon neutrality," he said.

Phillips says design changes can possibly extend longevity for wood poles. Researchers at the EPRI, for example, have developed a type of wood hydro pole that could better withstand extreme weather events. In the event of a storm, only the crossarm would break, or the wires would slip off, rather than having the pole itself break.

"When a wood pole is broken, it's going to take you 36 hours (to repair). But if you found a broken crossarm across the top, or a conductor that's just slipped in its footing, that can take three or four hours. And so that can really speed up recovery," Phillips said.

Phillips says it's imperative that policy makers start thinking now about how to build climate resilient electrical grid, whether it's designing stronger infrastructure to withstand extreme weather events or creating infrastructure that can be repaired more quickly.

"We really need to think about what the future is going to look like. Obviously, nobody has a crystal ball, but the climate models are getting better and better," he said. "We should be not waiting until then to design infrastructure that can withstand those events. We should be thinking now."