By Alisha Roemeling

The Register-Guard (Eugene)

Temperatures in Oregon are forecasted to be low over the weekend with intermittent snowfall expected, according to the National Weather Service.

That cold weather may find some residents bundling up, turning up the heat and opting to keep out of the cold by staying home.

For people who drive electric vehicles, the cold front may mean a shorter drive range for their car.

Research shows electric vehicles operate far less efficiently when temperatures drop, especially at 20 degrees or colder, according to the American Automobile Association.

That’s because, the AAA said, when temperatures reach 20 degrees and vehicle’s heating system is used, the average distance an electric car can travel, decreases by 41 percent.

“Research shows that electric vehicles thrive in more moderate climates,” said Marie Dodds, public affairs director for AAA Oregon/Idaho. “The reality is that most of us live in areas like Oregon where we do experience extreme weather from time to time, so EV drivers need to know how hot and cold temperatures can impact their driving range.”

Juan Serpa Munoz, a business line manager for electrification with the Eugene Water and Electric Board, said cold weather already decreases the efficiency of an electric vehicle, and using the heater when it’s cold taxes the car even more.

“The battery not only provides you with the ability to use the steering wheel, but it’s also being used to heat the car,” he said. “Plus, it’s cold, which is tough on batteries in general.”

The Oregon/Idaho branch of AAA this week urged electric vehicle owners to be aware of a reduction in range and the need to charge more often to minimize the chance of being stranded by a dead battery.

Across the state, there were 18,158 electric vehicles registered with DMV as Feb 1.

For the study, AAA tested five electric vehicles, all with a minimum EPA estimated driving range of 100 miles, in partnership with the Automotive Club of Southern California’s Automotive Research Center.

Driving conditions were simulated using a dynamometer, or a treadmill for cars, in a temperature-controlled space.

To determine the effects on driving range, scenarios for cold and hot weather conditions — when using heating ventilation and air conditioning and not — were compared to those of driving with an outside temperature of 75 degrees.

Vehicles used in the study included a 2018 BMW i3s, a 2018 Chevrolet Bolt, a 2018 Nissan Leaf, a 2017 Tesla Model S 75D and a 2017 Volkswagen e-Golf.

“The use of heat when it’s 20 degrees outside adds almost $25 more for every 1,000 miles when compared to the cost of combined urban and highway driving at 75 degrees,” the study said.