Electric buses are passing a brutal cold-weather test in Wisconsin

Jonathan Mertzig was wary when Madison rolled out a fleet of 62 electric buses in the fall of 2024. The city had tested a few of them four years earlier, and it had not gone well. Winter in Wisconsin gets mighty cold, and batteries do not like the cold. 

“Operationally, they were a nightmare,” said Mertzig, a member of the Madison Area Bus Advocates. “Every time you got on one there would be an alarm going off. You never knew when one was going to die in the middle of the road.” 

Cities across the country have experienced similar growing pains while electrifying public transit. A study conducted in Ithaca, New York, found that range can plummet by about half when the mercury hits 24 to 32 degrees Fahrenheit. That makes Madison, which sees an average of 18 days below zero each year, a tough proving ground. Riders like Mertzig, who experiences severe migraines and avoids driving, need the buses to run no matter what.

This time, they’ve done just that.

Metro Transit, which provides about 9.1 million rides annually, installed overhead chargers on key routes, allowing buses to quickly top off at several stops. Improved battery capacity also lets them go further between plug-ins. The real test came January 23, when the temperature dropped to -4 F, shutting down the University of Wisconsin-Madison — but the buses kept running.

That said, the rollout has not gone flawlessly. Last year the transit agency apologized when the overhead charging system malfunctioned, sidelining buses. In January, maintenance issues forced it to reduce service on two routes, but officials insist cold weather was not a factor.

Just a few years ago, electric buses routinely faltered in cold conditions, reinforcing doubts about whether they could replace diesel and natural gas-burning fleets in northern cities. Now, with better batteries and strategically placed chargers, Madison is at the forefront of a small but growing number of cities testing whether those doubts still hold. Making the technology work through a long Midwestern winter could reshape how others approach electrification. Some 3.6 million commuters nationwide rely upon buses to get around. With transportation accounting for roughly 28 percent of the nation’s greenhouse gas emissions, transit agencies are looking for alternatives to polluting machinery that creates a particular health risk around bus stops. Madison is among more than 100 U.S. cities that have pledged to reach net-zero emissions by 2050. Electric buses are key to that goal.

Metro Transit’s first experiment came during a broader effort to launch a system that could carry more riders with lower emissions. The city rolled out three electric buses — which cost $1.3 million and were funded in part through a federal grant — in 2020 to see how they’d do in daily service. Although the pilot introduced Madison to zero-emission transit and helped build institutional know-how, the Proterra buses were dogged by battery and maintenance issues. The city has since purchased coaches built by New Flyer. 

“We had no real success with Proterra,” said Joshua Marty, the agency’s facilities manager. Beyond the range challenges, his team had trouble sourcing parts and maintenance from the company, which declared bankruptcy in 2024.

Batteries have gotten significantly better in the short time since Madison decided to go electric. “Energy density has been increasing at roughly 7 percent per year over the last decade,” said Eric Kazyak, a mechanical engineer and professor at the University of Wisconsin, Madison. That boost has helped the 60-foot buses become the workhorses of Madison’s fleet. They work the city’s Bus Rapid Transit lines, and fill in on popular routes near the university campus.

Buses that work Route A — which runs east-west across the city — can stay out for most of the day because they recharge during routine layovers at each end of the run. The driver settles beneath an overhead pantograph “quick charger” for about 15 minutes. That boost allows each coach to travel as far as 258 miles a day. By the time it reaches the end of the line, the battery has dropped by 15 to 20 percent — a gap the charger refills in as many minutes. At night, the fleet returns to a dedicated depot with 16 slightly slower, but still plenty zippy, quick chargers. 

The north-south Route B does not yet have overheard charging hardware, so buses trundle around for four hours before returning to the depot with roughly 25 percent on their battery. The city plans to add pantographs to the route at some point, a move that would nearly double the time those rigs spend carrying passengers. Still, even the coldest winter days don’t reduce range by more than 10 percent compared to a balmy summer afternoon.

Between 60 and 70 percent of the fleet is typically running at any given time, with the rest in for maintenance and cleaning or being used to train drivers — a figure that Cody Hanna, the transit agency’s transit maintenance manager, said is unaffected by weather. The biggest challenge has been getting parts for the buses, which are more complex than their diesel counterparts and trickier to diagnose when something goes sideways. “With an electric bus, it could be an inverter, it could be a motor, it could just be a bad wire, could be a bad sensor,” he said. “There’s so many different things that are talking to each other.”

While on-route charging has been a boon for Madison, it could be cost-prohibitive for smaller cities. “This is a really good idea,” said Max Zhang, a mechanical engineer and professor at Cornell University who led the study in Ithaca. “At the same time there’s also cost issues. Those charging stations, my understanding is they’re not cheap.”  

Pantograph chargers typically cost roughly the same as the $1.5 million that Madison spent on each bus. Yet they might have actually saved the city money. Without them, Hanna said, Metro Transit would need to triple the number of buses running on Route A from 18 to 54. 

Those tradeoffs are playing out at a moment of federal retrenchment. The Trump administration has sought to curb electric bus investment. An analysis by the nonprofit advocacy organization Transportation for America found that only 3 percent of federal “low or no emission” program grants awarded last year went to zero-emission buses. 

Nonetheless, other frigid cities, including Minneapolis and Duluth — once a poster child for the technology’s failures — are expanding their clean energy fleets, and Milwaukee has embraced on-route charging.

But Mountain Line in Missoula, Montana, might be furthest down the road. Although it doesn’t get as frigid there as it does in Madison, the city experiences a week or two of temperatures below zero each year. Missoula also sits in a valley, trapping diesel exhaust. It began the transition toward electrification in 2018, and has since replaced about 90 percent of its fleet — putting the city well ahead of its goal of being entirely electric by 2034.

Jordan Hess, the transit agency’s CEO, began working with electric buses in 2016 as transportation director at University of Montana. Back then, the buses would recharge on the route much like those in Madison. Missoula’s coaches have batteries big enough to complete runs without topping off. It also helps that Mountain Line, like Metro Transit in Madison, uses diesel-powered heaters to keep passengers warm.

“They’re a little bit like chickens,” Hess said of the buses. If the temperature falls below zero, “they start squawking. You start taking precautions, and you start thinking about heat. I think of electric vehicles the same. [It] can get pretty darn cold before you have a lot of problems.” 

The buses have also brought changes for operators. Shanell Hayes has driven diesels and electrics in her three years with Metro Transit. Last winter, while returning to the depot to recharge, the lumbering bus suddenly topped out at 35 mph, then 20, and then just 2. She pulled over to wait for a supervisor, who followed her the last mile to the bus barn. It took an hour, testing her faith in the technology. Still, she likes how the behemoths handle snowy, icy conditions. Regenerative braking uses the motor to help slow the vehicle, sending power otherwise lost as heat back to the battery. It allows for a lighter touch on the brake pedal.

“I just take my foot off the gas and just allow it to slow down on its own,” Hayes said. “That way I can use my brake minimally without sliding.”

Rabbit Roberge was in his first week driving when he pulled up to a pantograph charger at the western end of Route A on a cold January morning. He drives a Toyota Prius, so he’s familiar with regenerative braking and the benefits of electric propulsion. He’s a fan of the tech. “They’re smoother,” he said of the buses. “They’re not as loud. They’re just all-around nicer to drive.”

Riders, too, seem to have embraced the change, though there have been challenges. Susanne Galler, who has been riding regularly since giving up her car in 2000, was still getting around on crutches after a bike accident in 2024 when she noticed that most of the seats in the e-buses require a step up to reach them. She also has seen one bus require a tow, and another that died at a stoplight. Still, she considers the transition to zero-emissions machinery as a “positive step.”

Kira Breeden, a doctoral student at the university, regularly takes the Route A to campus, particularly when it’s too nasty to ride her bike. She finds the buses to be dependable.

“I think it’s a really good system,” she said. “I’ve heard occasionally people complain about the timeliness of buses, but I’ve never had any issues, except for one snowstorm my first year, which makes a lot of sense, because it was dumping snow.” That storm occurred in March 2024, before the electric fleet rolled out, so it was probably a diesel bus that left her stranded. It’s a reminder that cold weather can sideline any machine.

Support for this story was provided by The Neal Peirce Foundation, a nonprofit dedicated to supporting journalism revealing ways to make cities and their surrounding regions work better for all people.

This story was originally published by Grist with the headline Electric buses are passing a brutal cold-weather test in Wisconsin on Feb 23, 2026.