At least three school districts in San Diego County are involved in testing a new 48-seat all-electric school bus developed by TransPowerin Poway, Calif., as part of a state pilot program to introduce school districts to clean-energy bus fleets.
Escondido Unified High School District just concluded its monthlong trial and sent the bus to nearby Cajon Valley School District for the second phase. Robert Berkstresser, transportation director at Escondido Unified, told STN that local air board officials approached area districts more than a year ago to see if they wanted to participate in TransPower’s pilot program and road-test the electric school bus. Berkstresser was one of the first to say yes, so earlier this year he worked with the company to get the electric bus inspected and registered to the Escondido school district. While the process of getting a CHP number was a bit complicated, he said they did it in time to roll out the bus in March.
Berkstresser used the electric bus on one morning route each day and found it could run about 60 miles before needing to be recharged in his shop, using a basic 60-amp outlet. He drove the bus himself several times and said it was so quiet at takeoff, it reminded him of the Monorail at Disneyland.
“It was novel. The kids really enjoyed it. This particular route happens to be our School for Applied Sciences, so a lot of the high school kids were very inquisitive. They asked a lot of questions, and thought it was pretty unique. The driver liked it well enough, but at the end of the day it doesn’t have the power of standard diesel bus,” he noted.
At the start of the trial, Berkstresser said the bus would return to the yard with a 6- to 10-percent reserve — but that doubled to about 20 percent by the end of the testing period. “A lot had to do with how the driver operated it, because the less you use the brakes and the more you allow the bus to decelerate on its own, you would recoup some energy to the batteries. So driver technique would determine your distance and battery life for the trip,” he explained.
Joshua Goldman, VP of business development at TransPower, told STN their engineers have been monitoring system performance, fuel (battery) economy, range and efficiency, especially in light of the varying routes at each district, while also providing real-time diagnostic information to learn from during the demonstration project. Funding comes from the San Diego County Air Pollution Control District and California Air Resources Board, whose goal is to reduce diesel fuel emissions that can pose health risks to schoolchildren.
So far three school districts have signed on to operate the electric bus for one month and then give feedback to TransPower, which opened its doors three years ago.
“The drive system has been in development for three years, leveraging hundreds of years of electric vehicle and hybrid vehicle expertise from TransPower staff. We’ve got a dozen professionals with 15 to 45 years of experience [with] heavy-duty alternative fuel vehicles,” Goldman said.
He added that this early stage of testing has been “extremely successful” and turned up a couple of surprises.
“One thing we didn’t expect was the higher speed in extremely hilly terrain of some of these operators for a system that is well-suited to urban and suburban areas,” he continued. “Another surprise is the diverse nature of the ‘mom and pop’ small district operations where any given day they could be doing special needs, regular-ed. or field trip service, with one bus having to fulfill all those needs.”
Goldman noted the electric bus has a range of 35 to 60 miles per charge, which could be up to 120 or more miles a day across two shifts if it has a mid-day, 90-minute charge. And, there is an option to double the battery size to enable the bus to go 240 miles a day with a mid-day charge.
Each battery currently costs $80,000 to $90,000, but Goldman stressed that they expect the cost to come down in the next 10 years.
Berkstresser said the price of the battery and the vehicle itself would both have to drop significantly before he would seriously consider adding a fully electric bus to his fleet.
“I can see where it would be viable in the future. Two big things have to happen: the overall price of the vehicle has to come down and the range would have to increase … to around a 150-mile range,” he continued. “A lot of times in transportation you’re changing things on the fly. A student may be left behind, so you have to go back for him, or a teacher called and forgot to order a field trip bus, so you have to drop off students and then grab others to take to the zoo, for instance. Your hands would be tied if you couldn’t send that bus because it didn’t have the range.”
Still, Berkstresser is pleased he participated in the demonstration project because of all that he and his drivers learned about this alternatively powered yellow bus.
“From that standpoint, it was good. It’s a good training model for future drivers that are going to be operating it,” he concluded.
Look for an update on the electric school bus demonstration project going on in northern California next week on stnonline.com.
