In Chicago, adapting electric buses to the challenges of winter


March 4, 2023 GMT

CHICAGO (AP) — The No. 66 bus is packed on a late weekday afternoon as it starts and stops on its way from Chicago’s near west side to Navy Pier on the shores of Lake Michigan.

The seats and windows squeak and rattle like a regular diesel bus, but nobody seems to notice the high-pitched whine of the electric motor that powers it.

That’s exactly what the Chicago Transit Authority wants. Buses that aren’t yet polluting the air can travel the route with the same reliability as those that are, even when cold weather affects battery range.

However, for electric buses to work, the CTA had to put in a lot of effort and expense. At both ends of Route No. 66, fast charging stations have been set up, which are connected to the bus roofs.

Drivers constantly monitor the batteries to make sure they don’t run out and risk stranding the bus. If they get below 50% charge, they should charge them on a charger.

“We are meeting the daily challenges of Chicago’s inclement weather,” said Don Hargrove, senior maintenance manager for the workshop that houses most of the agency’s 23 electric buses.

CTA began experimenting with electric buses in 2014 and has developed a system that Hargrove says will work when the transit agency transitions to an all-electric fleet by 2040.

Other transit systems are going through the same process to reduce pollution and combat climate change.

Cold weather is the CTA’s biggest problem. When the temperature drops, the lithium-ion batteries that power the buses aren’t as efficient and lose range. Most of the energy drawn from the batteries is used to heat the bus interior to 21°C (70°F).

“Every time the bus stops to pick up passengers and let people off, the doors are opened,” said Richard Lin, deputy chief of bus equipment. “You need to warm up this new batch of cold air.”

The electric buses have a small diesel engine that heats the interior in extreme temperatures to increase battery range, Lin said. Most of the time, however, the buses use electric heating coils, similar to a giant toaster, which can drain batteries. When CTA bought their buses, more efficient heat pumps weren’t available as an option, he said.

For every 10-mile one-way trip on Route #66, the electric buses lose about 8% of their battery power. In the winter, they start out with a range of around 100 miles when fully charged. After about six one-way trips, the policy requires drivers to charge a fee if they fall below 50%.

Typically, the schedule is for 10 to 15 minutes to charge, and the buses receive about 1% of a full charge for every minute they are plugged in.

With enough chargers, the electric buses could run all routes, Lin said. “It’s just a question of our strategy to put the chargers in the right locations and have enough chargers available as we grow our fleet.”

Currently, the CTA has about 1,900 buses, most of which run on diesel fuel. The transportation system is starting to swap them out for electric ones, but the investment is huge. Each electric bus costs about $1.1 million, about $500,000 more than a diesel model.

But after the initial capital expenditure on the buses and charging stations, the electric buses are much cheaper to run. The CTA calculates that it costs $2.01 per mile to operate the 40-foot electric buses. It’s $3.08 per mile for a diesel bus and $2.63 per mile for a diesel-electric hybrid.

It would be decades before the agency would recoup its investment in the electric buses, but CTA officials say the cost of electric buses will come down as more are sold.

AP Video/Teresa Crawford)

In the Alaskan capital, Juneau, which has a more temperate climate but winter temperatures can still drop below zero, officials also have plans for an all-electric bus fleet, though one they got in 2020 was plagued by mechanical problems.

Capital City Transit has ordered seven electric buses to replace diesel models beginning in 2010, said operations manager Rich Ross. The new buses are set to run regular routes due to increased battery capacity “which wasn’t available when we ordered our first bus,” he said.

Cold winter conditions could still cut the new buses’ expected 282-mile range by 100 miles, allowing them to be used on the coldest days on commuter routes that only operate during peak hours, Ross said.

Like Chicago, Capital City Transit plans to build an “on route” charging station where buses can plug in when they run out.

Back at No. 66 in Chicago, Dawn Carter, 54, says she’s glad electric buses are running on the route because they’re good for the environment.

The only difference is that the electric buses are quieter than those with rattling diesel engines and noisy heaters, but few people notice, she says. “When I come to work, everyone rushes to get in and out,” she says. “It’s just quieter. It’s easier to talk to people. When the heating goes on and off, you hardly notice it.”


AP reporter Becky Bohrer in Juneau, Alaska, and video journalist Teresa Crawford in Chicago contributed to this story.


The Associated Press’s climate and environmental reporting is supported by several private foundations. Learn more about AP’s climate initiative here. The AP is solely responsible for all content.

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