K.C. Baylor, who has been driving an MTA bus for 15 years, was one of the first drivers to get behind the wheel of an all-electric bus.

"It's much quieter. You don't hear too much noise," Baylor said. "It's a very good acceleration on the bus, and it handles very well."

And no exhaust from a diesel engine to breathe in, he said.

"When you're driving electric, there's nothing. No smell, no nothing," he said.

The MTA is expanding its fleet of electric buses since it launched a pilot in 2017.

"We found out that on certain routes that the buses work just fine. However, we recognize that about a third of our schedules today could not be operated with the current technology of electric buses," said Craig Cipriano, the head of buses at MTA.

The MTA has five electric buses on 42nd Street and 50th Street crosstown routes, five on routes in Brooklyn and Queens, and 15 60-foot accordion-style buses on the 14th Street and 125th Street select bus routes.

The agency has collected data to see how well electric buses run on city streets. For example, the buses on the two Manhattan Select Bus Service routes can run up to 93 miles on daily trips that average 26 miles.

"We're making about three to four trips with those buses before they have to come back for a charge," Cipriano said.

One advocate said the figures are encouraging for the future of an all-electric bus fleet.

"What these numbers really show us are that the newer buses, different options on different routes really do impact the way these buses are able to operate, but that the newer ones are incredibly feasible and very operational," said Lauren Bailey, director of climate policy at the Tri-State Transportation Campaign.

Cipirano, head of MTA buses, says that technology must advance in order to meet its goal of an all-electric fleet.

Batteries must be able to withstand longer trips, while powering heating and air conditioning in particularly hot or cold days. And there must be an expansion of charging infrastructure on streets and inside depots.

"What we realize is that we probably would need 10 times the amount of power coming to our bus depots than we have today," Cipriano said.

The MTA plans to purchase more than 2,400 new buses. More than half of them will run on diesel fuel, but that purchase also includes 500 fully electric vehicles, as well as hybrid and natural gas buses.

Meanwhile, the MTA plans to stop buying diesel buses by the end of the decade.

The agency is planning to spend more than $1 billion over the next four years on electric buses.

The MTA's goal to is achieve a fully electric fleet by 2040.