This article was published by The Energy Mix on Jan. 26, 2024.
By Christopher Bonasia
Last week’s cold snap brought North America its lowest temperatures so far this winter, precipitating a flurry of reports about electric vehicle batteries failing in the cold—but EV drivers in some of Canada’s frostiest parts have their own story to tell.
In the Northwest Territories, where winter temperatures go as low as -45°C and stay below -30°C for weeks at a time, conditions can be challenging for EV batteries. And yet, the YK EV Share Co-op has been running successfully in Yellowknife since 2020, and operating year-round, even in bitter cold weather. The co-op started off with a 2016 Chevrolet Spark EV, then added a Chevrolet Bolt in 2022. It cars are used by 40 shareholding lifetime members, and more than 120 drivers are registered.
Comparing EVs, ICE Vehicles in the Cold
Following a mid-January freeze, a New York Times article described the tribulations of hapless Tesla owners facing low winter temperatures in Chicago: lineups at charging stations and calls to tow trucks for stranded vehicles that wouldn’t start. Similar stories ran in Newsweek, NPR, CBS, and other news outlets.
But the reporting on the apparent crisis in Chicago gave an incomplete picture of how EVs perform in low temperatures, with some commentators noting the headlines carried a “fair dose of sensationalism.” EV battery performance is indisputably affected by cold weather, but conventional internal combustion engine (ICE) vehicles have their own limitations as temperatures drop.
EVs are powered by electricity, or energy produced by a current flow of electrons. In the lithium ion batteries that EVs use, the charge is increased and decreased by the flow of electrons and lithium ions between positive (anode) and negative (cathode) electrodes that are separated by an electrolyte. When charging or discharging, electrons move between the electrodes via an external circuit. For instance, when a vehicle is charging, electricity is stored in the battery through a charger, and during discharging, the circuit facilitates the flow of electrons to power the vehicle’s motor. Meanwhile, lithium ions balance this flow by traveling through the electrolyte.
Even in ideal circumstances, the current produced by a battery encounters internal resistance from factors like the materials in the battery’s electrodes, the electrolyte, and the other points that collect and connect the current. But what is important for battery function in cold weather is that lower temperatures increase that internal resistance, which in turn reduces the battery’s efficiency, voltage, and capacity. For EVs, this means the battery can take longer to charge and will travel smaller distances. Recent reports indicate performance reductions as great as 30 to 50 per cent.
ICE engines are instead powered when fossil fuels combust—after being exposed to an electric spark in gasoline cars, or after the fuel is compressed in diesel vehicles. Not only do these fuels often have lower energy density in the winter, but ICE vehicle engines and transmissions also have a far greater number of moving parts compared to EVs. Before they warm up, those components are stiff and experience higher friction that reduces fuel efficiency, especially as engine oil and other inline fluids become more viscous in the cold. (Unlike ICE vehicles, EVs do not require motor oil.)
According to fuel economy tests, a conventional gasoline car will achieve roughly 15 per cent lower gas mileage at -6°C (20°F) compared to 25°C (77°F). And the impacts of cold weather are most significant for vehicles that make frequent short trips, since they lose efficiency in the time the engine takes to heat up to an optimal temperature. Robinson noted anecdotally that, in his own experience driving a 2004 Volkswagen Golf TDI (diesel), his ICE vehicle too experiences lower performance in the winter. “The average fuel consumption on my TDI goes from five litres per 100 kilometres in summer to over 10 in winter,” he said.
But there is another critical difference that makes the impact of cold weather more dramatic for EVs. The amount of energy that is actually converted to power an ICE car is only a small portion of the energy produced when fossil fuels combust in its engine. According to the American Automobile Association (AAA), “today’s gasoline engines are only around 30 to 35 per cent efficient, which means roughly 65 cents out of every dollar you spend on gas goes to waste.”
So ICE engines are woefully inefficient to begin with, and most of that energy is usually lost as wasted heat. The exception is in the winter, when that heat is diverted to the car’s interior, so heating the cabin doesn’t require any additional fuel.
EVs, on the other hand, use energy much more efficiently, but heating the interior requires additional energy from the battery. That leaves less available for traveling—though some newer models are designing EVs with heat pumps that can warm the interior more efficiently.
The experiences at the YK co-op also reflect this, with Robinson observing that “the cabin heater can use up to 90 per cent of the electricity during a rental—especially as some Yellowknifers have understandably developed the habits of cranking the heat to maximum and leaving the vehicle ‘running’ (for EVs this means leaving the heat on) while they do their shopping.”
But Robinson did note a difference in the co-op’s two vehicles: the small, 19-kilowatt-hour battery in the 2016 Spark was fine for most single-family type driving needs, but “it was not quite enough to keep up with car sharing where it was being used constantly in -30°C.” He says it lasted only about three hours if the heat was turned up high.
“We didn’t have any fast chargers to top it up, so we switched to weekly rentals where it would get used less intensely,” he explained. “Now that there are two L3 fast chargers in town, we are considering bringing the Spark back to hourly rental duty.”
The Bolt, meanwhile, used a 65 kWh battery and presented no issues. “It can operate with the heat cranked for 10 hours” or more, he said.
[The other unexpected lesson for EV drivers is that heated seats, which some see as a luxury in ICE vehicles, become an unsung efficiency measure with an electric motor. Given a choice between heating the whole cabin or just warming the passengers, heated seats save battery power.—Ed.]
In the summer months, running the air conditioning in an EV has far less impact on driving range, until outside temperatures reach triple digits. Not only does the AC use less energy than a resistance heater, but a smaller temperature change is usually needed to reach comfortable levels in summer compared to winter. Unlike heating in winter, air conditioning in ICE vehicles does mean burning additional fuel, though not a significant amount except in extreme temperatures.
EVs do have some benefits over ICE vehicles on cold days. While cars of both types will start on even the coldest of mornings as long as they’re kept warm overnight, EVs are built with a preconditioning feature that warms the battery to ensure it starts up.
As long as they’re plugged in when at their “home base,” both the EV and the TDI Golf will start in extreme cold, Robinson said. But EVs actually last longer than the ICE vehicles when they’re left unplugged, he added. “They draw power from the traction battery to keep themselves warm enough to operate, while an ICE engine will not start after a few hours if left unplugged.”
Needed: Better Infrastructure
Moving past the sensationalism of the headlines, the stories about Teslas failing in Chicago did acknowledge that circumstances were more complicated than first indicated. Part of the issue was infrastructure: EV owners lined up at charging stations had fewer options to choose from because three of the city’s charging locations were shut down.
“We’re just a few years into EV deployment at scale,” Albert Gore III, a former Tesla employee who is now the executive director of the Zero Emission Transportation Association, told the Times.
“This is not a categorical problem for EVs, because it has largely been sorted out in other places.” That includes countries with cold winters, like Norway.
Limited access to charging infrastructure is often cited as a barrier to EV adoption, and many governments are now scrambling to install chargers in their jurisdictions. However, out-of-commission charging stations in Chicago signal technology issues that directly affect EV performance, and these issues resonate in Yellowknife.
“The biggest issue with driving EVs in cold weather in Yellowknife is not the range—it is the connection to the charger!” Robinson told The Mix.
He explained that charging cables can become solid in Yellowknife’s low winter temperatures, making it hard to get a good connection. “The car and charger communicate over the cable and these communications connections are finicky,” Robinson added. “In cold weather, just brushing past the cable can break off the communications.”
The cables can also crack at the tip where they join the plug—which requires expensive replacement after the one-year warranty. And the powdery snow that falls during the NWT’s very cold winters can get compacted into the micro-switch that is meant to confirm that the cable is plugged in properly.
Ultimately, having more chargers around would help EV drivers travel longer distances in cold weather. Yellowknife, for example, has only one highway out of town that could take drivers down to Edmonton, more than 1,500 kilometres away. But Robinson says charging infrastructure along that route is limited. While he knows some EV drivers who’ve made the trip in summer, he guesses no one has tried it in winter—and he doesn’t recommend trying it.
“Many folks here like to do the Yellowknife to Edmonton or Grand Prairie trip in one shot, stopping only for gas,” he said, but “EVs are going to require a different mentality for that type of trip.”