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Predicting if, when and how the surge will happen is a challenge for the country’s utility companies

In certain urban neighbourhoods, it can seem like Tesla Model 3s, Volkswagen ID.4s and Chevy Bolts occupy every third driveway.

Zero-emissions vehicles accounted for nearly 11 per cent of all new motor vehicles registered last year, according to Statistics Canada – the first time they’ve topped one in 10. That’s more than double the 5-per-cent sales threshold after which some experts believe consumer preferences shift and mass-adoption ensues.

Charging a single EV draws as much energy as two average households combined, according to Toronto Hydro. Many observers have warned that rapid EV adoption will cause demand for electricity to surge.

So it might seem surprising that in Canada’s most populous province, Ontario, electricity demand actually declined in 2023 relative to the previous year. And in British Columbia, where adoption has been more rapid, there’s similarly been little impact despite 146,000 EVs hitting the road. (These gains notwithstanding, sales have lagged expectations in recent quarters in several countries, including Canada.)

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Forecasting how much electricity will be required to satisfy EVs in coming years is a difficult and high-stakes exercise. And while many Canadian utilities appear sanguine about it, a handful are already becoming apprehensive.

Literally billions of dollars ride on this question. Mass electrification has lately become the most often-cited justification for building power infrastructure at a pace not witnessed in decades.

Ontario plans to build nuclear reactors, natural gas-fired plants and wind farms to significantly ramp up electricity production.

BC Hydro recently unveiled a $36-billion capital plan for the next decade that’s about 50-per-cent larger than its predecessors. The utility says once its massive Site C dam is up and running, it could power another 1.7 million EVs. Utilities insist such investments are necessary because power projects take many years to plan and execute – they must act now to avert brownouts.

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BC Hydro's Site C dam, seen along the Peace River in Fort St. John, B.C., in April, 2017. The utility says once the dam is up and running, it could power another 1.7 million EVs.JONATHAN HAYWARD/The Canadian Press

But while the risk of being caught unprepared is genuine, so is the potential for overshooting. In Ontario, procurements of renewables early this century contributed to excess capacity during the 2010s, in part because electricity demand unexpectedly fell. Such missteps force utility customers to pay for unnecessary infrastructure.

Ralph Torrie, an energy analyst, said Ontario’s slight decline in electricity consumption last year demonstrates “there are things going on in the electricity system in this province that are not being captured by the central planners. And it’s leading them to overestimate the growth that is going to result from EVs and heat pumps.”

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Tesla charging stations at Applewood Village Plaza in Mississauga on April 25. According to Toronto Hydro, charging a single EV draws as much energy as two average households combined.Fred Lum/The Globe and Mail

EVs: For now, an insignificant source of demand

So why did electricity demand fall in Ontario last year? According to the province’s Independent Electricity System Operator, it had everything to do with the weather. “If you look back to 2022, we had a really cold winter and a really hot summer,” said David Devereaux, its director of resource planning. During summer, heat and humidity cause people to switch on their air conditioners – and in winter, those using electric heating increase their loads, too. He said the opposite was true of 2023: “It was a pretty mild winter, and the summer wasn’t as hot.”

What about all those new Teslas? According to IESO data, the incremental demand from EVs last year in Ontario was just 0.12 terawatt hours, as compared with a total provincewide demand of 133 TWh.

Curious about what was happening in neighbourhoods where early EV adopters are clustered, The Globe and Mail acquired new vehicle registration data by forward sortation area (the first three digits in postal codes) from the province’s transportation ministry. The data were compared with power use, with the expectation that it would rise, but in fact there was no notable increases in consumption.

The explanation for this is straightforward: Even as sales have increased rapidly, EVs still represent a vanishingly small portion of the overall stock of vehicles. According to the International Energy Agency’s latest data, from 2022, nationally they accounted for just 1.6 per cent of all cars on Canada’s roads. There’s simply not enough of them to make a difference – yet.

Plugging in to trouble

Utilities recognize that government policies are pushing EVs. Under federal targets, 20 per cent of vehicles offered for sale by auto manufacturers and importers must be zero-emission beginning in 2026; the proportion rises to 100 per cent by 2035. The City of Toronto wants EVs to account for 30 per cent of all registered vehicles by 2030.

Toronto Hydro, which serves nearly 800,000 customers in Canada’s largest city, sees trouble ahead. According to documents released in November as part of an application before the Ontario Energy Board seeking to increase rates, its forecasts show EV adoption accelerating in the 2030s, spurring big changes in electricity-consumption patterns. One is that peak demand, which typically occurs on the hottest summer days, will shift to winter. The IESO agrees: It expects that by 2030, the summer and winter peaks will be comparable, largely because of overnight EV charging.

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Toronto Hydro figures that proliferating EVs will begin overloading pole-top transformers, as well as stressing overhead and underground cables.Fred Lum/The Globe and Mail

Toronto Hydro figures that proliferating EVs will begin overloading pole-top transformers, so it will have to replace or upgrade many more than was previously necessary. Overhead and underground cables will also be stressed. Toronto’s grid features three different voltage levels – Toronto Hydro warns that neighbourhoods served by the lowest-voltage lines will face longer wait times for hookups, and higher costs to connect. It also figures it will have to hire many more technicians to connect EV chargers to the grid.

The utility warned the Ontario Energy Board that under the status quo, its capital investment plan would be underfunded by more than one-third, or about $1.5-billion. Customers might face declining reliability and much higher costs.

Most of Ontario’s utilities seem less concerned. In late 2022, the Ontario Energy Board surveyed 35 local distribution companies serving the vast majority of the province’s electricity customers about what impact EV charging would have on their distribution systems. Most respondents said it would have only a “marginal” impact for at least the next few years. Only two said it would have a “material impact” such that they would have to change their internal planning processes to adapt. A majority said they were watching their local EV market and taking a “wait and see” approach.

Some experts believe utilities have little to fear from EVs. At the country level, some studies have found that even full deployment might have only a modest impact – an increase of just 5 per cent or so in total electricity demand.

“Using information from Germany as an example, EV growth is not likely to cause large increases in power demand through 2030,” a 2018 commentary by McKinsey, the global consulting firm, asserted. “Instead, it potentially adds about 1 per cent to the total and requires about five extra gigawatts (GW) of generation capacity.” Even as late as 2050, McKinsey estimated EVs would add only 4 per cent to power demand.

Notably, though, nine respondents in the Ontario Energy Board’s survey said they didn’t have enough information to draw conclusions about how EV charging would impact their distribution systems.

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Cars charge at a residential EV charging station in Toronto in February, 2024. Toronto Hydro is experimenting with devices that track additional loads experienced by transformers as more EVs plug in.Laura Proctor/The Globe and Mail

Clouds of uncertainty

Even as utilities ponder the implications of future EV adoption, they often know little about what’s happening now.

Many respondents to the Ontario Energy Board’s survey, for instance, said they didn’t know where residential chargers are already installed. That’s because there’s no requirement for customers to inform them when they’ve purchased an EV or charger.

There are ways to infer where customers are plugging in, of course. Utilities can analyze data from meters, vehicle registrations and other sources to try to pinpoint them. BC Hydro said it’s monitoring EV adoption through customer surveys, enrolment in its EV rebate program and use data from its fast-charging network.

Toronto Hydro is experimenting with devices that track additional loads experienced by transformers as more EVs plug in. Its analytics team is also working to develop a system that would use machine-learning algorithms to scour smart meter data to identify electricity-consumption patterns that would likely be caused by EV charging.

“Greater insight into charging patterns and geographic EV adoption rates over time will allow Toronto Hydro to invest more efficiently in grid capacity and flexibility,” spokesperson Daniel McNeil wrote in a statement.

But to forecast how EVs might affect power consumption in the years ahead, utilities are compelled to heap assumptions on top of assumptions.

The National Renewable Energy Laboratory, a contractor-operated lab owned by the U.S. Department of Energy, has projected that electrification will require a doubling of electricity generation in all regions of the U.S. by mid-century. Matteo Muratori, NREL’s group manager of Transportation Energy Transition Analysis, was involved in generating those projections. It’s a tough job, he said, owing to the many uncertainties at play.

Among the biggest, Mr. Muratori said, is that it’s difficult to predict who’ll buy EVs first. “We think that demand is actually going to outpace supply,” he said. “There’s going to be more people who want EVs than the ability to produce the vehicles and install charging infrastructure and whatnot. It’s not clear who’s going to win that competition.” The winners determine where and how EVs are charged – details that could help utilities prioritize investments.

“If you ask me how many EVs are going to be sold in California next year, we think we can give a pretty decent projection,” Mr. Muratori said. “If you zoom in and you say, ‘Well, is it going to be Los Angeles or San Francisco?’ it gets harder.”

Further uncertainties concern when EV owners charge. Some early modelling exercises assumed owners would recharge batteries fully every night. But other researchers report that in the real world this often isn’t the case. According to the International Energy Agency, regular commuters may charge at home in the evenings, but they also might charge earlier at workplaces, provided chargers are available.

“It’s not just oh, well, you consumed 50 kilowatt hours,” Mr. Muratori said. “Do you want them in half an hour with a fast charger at noon? Do you want them over 10 hours overnight at home? That’s a very big difference from a power system perspective.”

Shaping the load

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LG EV charger technology on display at the 2024 Canadian International Auto Show. Changing technology presents yet another wildcard when it comes to forecasting how much electricity will be required to accommodate EVs in coming years.COLE BURSTON/Reuters

Changing technology presents yet another wild card.

Today, most EVs start charging the minute they’re plugged into a charging station, and keep drawing until the battery is full. Known as “uncontrolled” charging, it can threaten grids if large numbers of EVs plug in at the same time.

But EVs are often plugged into chargers for longer periods than is strictly necessary, which creates opportunities for “smart” or “controlled” charging. Smart chargers that allow owners to control when and how charging happens could reduce this risk.

Utilities also have plenty of options for influencing EV owners’ behaviour. One obvious tactic is to tweak time-of-use prices to incentivize them to charge when there’s more surplus power available. Ontario introduced last year a new “ultra-low overnight rate” plan of 2.4 cents per kilowatt-hour between 11 p.m. and 7 a.m., aimed specifically at EV owners. BC Hydro says it will also introduce time-of-use rates to shift consumption to overnight.

Customers don’t mind. Toronto Hydro conducted a pilot study on smart EV charging, and found many were often willing to consent to allowing the utility to pause their EV charging to move the load off-peak, if it saved them money.

“This is tremendously valuable insight for us because it signals that Torontonians who own EVs and charge them at home are prepared to work with us to shape loads on the system,” Mr. McNeil wrote.

A 2020 paper suggested that in Britain, smart charging could eliminate the need for new power plants even if EVs completely supplanted internal combustion engines, while at the same time reducing by two-thirds the amount of reinforcement required in that country’s distribution networks.

Theoretically, EVs could feed their stored energy back to the grid at moments of peak demand. Electricity grids would have to change considerably to facilitate two-way flows, but if that happens, EVs might help improve rather than impair grid stability.

But EVs aren’t simply batteries on wheels. They’re an important way for people to get where they need to go. This, for modellers such as Mr. Muratori, is yet another consideration.

“We are always very careful to represent those mobility needs,” he said. “If in the morning you need your EV to be at an 80-per-cent state of charge, sure, maybe that’s inconvenient for the grid. But you bought the vehicle because you need it.”

Utilities still have time to figure all of this out. Mr. Muratori acknowledges NREL’s scenarios for EV adoption are aggressive, but even so, it expects EVs will continue to account for only a small portion of total electricity demand in the U.S. for the remainder of this decade.

“Of course, we see major increases in electricity demand because of EV charging” by mid-century, he said. But “if you look even at 2030, it’s pretty small.”

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