A new study shows the switch to electric buses may be tricky in colder climates.
Cornell University mechanical engineering professor Max Zhang said there are potentially a lot of upsides to using electric buses.
"There are potentially environmental benefits," he said. "You reduce greenhouse gases. There are health benefits in terms of reducing human exposure to diesel exhaust."
But there are also challenges. Zhang and other researchers at Cornell looked at how seven electric buses responded to the Ithaca area over a two-year period.
The study found that batteries on the electric buses consumed 48 percent more energy in cold weather (25-32°F). Zhang said it’s more efficient to charge electric vehicles when the battery is still warm, but buses are used more frequently than electric cars.
"For electric buses, they're operating all day, and the only time, potential time, you can charge them is after their service," Zhang said.
For optimal battery usage, communities with cold weather could work toward providing enough inside space and charging stations to charge their buses immediately after their routes. Zhang also pointed out that buses can struggle to keep cabins warm in the winter, particularly in urban areas with frequent stops for passengers.
"I think that definitely is another reason for the higher energy consumption for electric buses, to basically maintain the cabin temperature to the desirable range," he said.
In this situation, communities could consider having the bus doors open for less time at each stop.
Zhang said he’d like to see more pilot studies to provide additional data to communities, so they can see how to mitigate these challenges, and manufacturers, so they can develop products that would work well in different types of climates.
