Pros and cons
Wichita just put its buses on the street a few weeks ago and Proterra will be training its drivers.
“If a driver operates the bus properly, they can regenerate 20% of the power while they’re driving,” Tann said. “With electric buses, when you take your foot off the accelerator, it goes in reverse and regenerates electricity. Once you train the drivers, you can almost have a competition on who can regenerate the most electricity.”
Wichita will only let the battery get down to 20%, and from 20% to 100% takes six hours. Once it’s fully charged, it’ll go into “trickle mode.” Tann explained the two different types of buses have different charging methods. The four Proterra buses have their own charging stations, so when the buses come in, they get plugged in. The Complete Coach Works buses have the charger integrated into the bus and use 220-volt electricity.
Some of the pros for electric buses include they have fiberglass bodies so they don’t have corrosion, the brake line lasts three times longer, no oil to change, no combustion engine, etc. This enables the city to save on preventive maintenance. They’re also quiet so passengers can converse inside or outside the bus.
Tann said the city leases the battery packs from Proterra so in six years it’ll get new battery packs and the old lithium batteries will be repurposed.
“It has a long life for its main purpose, and then it can be refurbished for new use,” he said.
One negative is the cost of the bus and the infrastructure. The Proterra buses reportedly cost around $800,000-$900,000 each.
“The disadvantages are short term and up front,” he said. “New technology always costs more,” but he added, as more are sold, the costs go down.
The cost difference between diesel and electric buses has already shrunk from just a few years ago with the difference now about $120,000-$130,000, according to Tann. But he said right now with the low-no emission grants the federal government pays 90% of that cost.
Tann acknowledged the grant money is “very competitive, but it’s certainly well worth doing if the community is willing to invest in the other part — the infrastructure.”
Tann believes the cost of the bus and battery technology will continue to get better and less expensive as more units are put into service. He acknowledged, while Wichita’s buses are still in the commission phase, he doesn’t think they’ll have any of the issues other municipalities have had with battery degradation with the extremes of hot or cold weather.
“It’s probably not going to affect us — our buses are garaged,” Tann said.
Now Tann has had the opportunity to work with fleets using diesel fuel, CNG and electric, and so far, he thinks he prefers the electric systems.
“The FTA is 100% behind this — it’s a great way to diversify your propulsion and get away from fossil fuels. I highly recommend every public transit agency to look at where electrification can be beneficial.”
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