Quebec risks experiencing even more outages because of old Hydro transformers

More than half of Hydro-Québec’s overhead transformers are over 25 years old, which risks increasing the number of outages in residential neighborhoods.

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“It’s a bit inevitable. When you have a car that is around twenty years old and has 700,000 km on the clock, it is certain that the risks of failure are higher,” says François Bouffard, professor of electrical engineering at McGill University.

And of Hydro’s approximately 600,000 overhead transformers – found in poles – approximately 57,000 are at least 40 years old, or nearly 10%.

Approximate data

In fact, the situation is arguably worse today since the data we obtained dates back to 2017, the date of the last “assessment” carried out by the Crown corporation of the age of these devices.

Hydro-Québec will therefore have to accelerate the pace of transformer replacements to prevent its distribution network from becoming even more vulnerable than it already is. Especially since the electrification of transport increases pressure on the network.

Remember that in a scathing report published in December 2022, the Auditor General found that Hydro had “not adapted its strategy to the context of the aging of its assets”.

“A more tailored strategy could, for example, prescribe replacing certain assets earlier than currently planned in order to mitigate work overload and increased breakdowns in the years to come,” the report read.

Drop by drop

Hydro-Québec then estimated that the number of overhead transformers to be replaced each year would increase from 8,500 in 2019 to 14,000 in 2030.

As for the number of poles to be replaced, the state corporation projected that it would increase from approximately 7,000 per year to 30,000 by 2035.

However, in 2022, Hydro replaced less than 5,000 poles preventively, compared to 6,250 in 2021 and more than 7,000 in 2020, the QMI Agency revealed last year.

Hydro-Québec was unable, this week, to tell the Journal how many overhead transformers have been replaced in recent years.

Rusty but still brave

Professor Bouffard notes, however, that transformers can continue to function well even if they have exceeded their useful life, which is generally estimated at 30 or 40 years.

“The primary cause of failure of pole transformers is external things like weather hazards, animals and automobile accidents,” he emphasizes.

“Sometimes we see some that are rusty, that are really not pretty, but they continue to do their job and probably if we leave them alone they will continue to do it,” explains the specialist.

Note that several other North American electricity companies are also struggling with aging transformer fleets.

In 2022, the Auditor General observed that Hydro-Québec had only implemented part of its 2020 outage reduction plan, which notably provided for the strengthening of 400,000 transformers.

Michael Sabia, who has been at the helm of Hydro since last year, promised to correct the situation. Its action plan, which extends until 2035, plans to devote at least $8 billion to increase the reliability of the state-owned company’s distribution network.

Hydro-Québec hopes to “reduce the number of outages by 35% within seven to 10 years,” specifies a spokesperson, Louis-Olivier Batty.

Age of Hydro-Québec overhead transformers

• 40 years or older: 9.4%
• 30 years or older: 39.3%
• 25 years or older: 55.7%

Note: data as of 2017

Source: Hydro-Québec