RENO, Nev. — Following a welcome announcement by STN President and Publisher Tony Corpin, the Green Bus Summit addressed the scalability of electric school buses.
Moderated by Corpin, panelists Craig Beaver, Alex Cook and Cian Fields discussed their respective fleet electrification journeys and the intricacies of infrastructure adoption.
First Student, for which Cook is the chief engineer, is currently undergoing one of the largest electric school bus deployments in Montreal and is working on another 34 projects with 80 more in the queue. The company has previously said it aims to electrify 30,000 of its 45,000 school buses across North America by 2035.
Cook noted that sharing successes and best practices will further the industry toward the adoption of electric vehicles and the destination of zero emissions. To do so, he suggested that one must consider worst-case scenarios. For example, if the charger or battery management system goes down, the bus still must take children to school.
He added that the battery state of health is also very important, and will change based on the introduction of V2G as well as the type of charger being used.
Beaver, the administrator of transportation for Beaverton School District near Portland, Oregon, said his operation is currently operating 25 electric buses, and he expects to have 30 in the next month for a total of 90 by next summer. He said Beaverton’s key to success has been using Level 2 chargers that are less expensive and optimal for battery health.
He said he has had to consider battery capacity for wintertime operations. Beaverton currently operates a handful of buses that are using 155 kW batteries, but because drivers use the heater during their routes, Beaver said there wasn’t enough charge left for afternoon routes. Now, he said, the lowest battery capacity Beaverton purchases is 195 kW, but the majority of buses are running at 210 kW.
Fields, the electrification manager for Boston Public Schools, said Massachusetts’ largest school district has been running 20 electric school buses for the past 18 months. Within the next two years, the district is hoping to add another 95 buses to its fleet amid its plans to fully electrify. Fields said efficiency is most important when operating in colder weather. This requires both a workforce component and a technology component.
For workforce, he said BPS does a training refresher course and pushes the importance of regenerative braking as well as keeping windows closed while on route. On the technology side, however, he said fleet managers advise preheating the cabin while the bus is plugged in. This retains the most charge for the bus as BPS uses 30 kW DC Fast chargers. The electric heaters take 20 kW of the charge, he added.
Considering Infrastructure
Fields said the first round of charging infrastructure was installed above ground last summer and took eight months to complete. He explained that above-ground was a little more expensive but led to faster deployment. He noted that other benefits include the ability to move the infrastructure. Right now, the district is adding additional chargers via trenching, and is so far having great success.
Beaverton, on the other hand, went with a make-ready program through the local utility and trenched underground for 31 chargers. Beaver said the district is currently in the process of adding another 36 Level 2 chargers also underground. However, he said, he is interested in the above-ground models as they provide the ability to move the systems and offer quicker adoption time.
Cook explained First Student’s FlexCharge above-ground model of charging. He explained that it’s as simple as loading it onto a flatbed trailer and shipping it to the location. The system contains all the necessary components including transformers, switch gear, chargers, distribution panel, and master switch. This solution is generally available for fleets with 10 or more electric buses, but there is also a kit available for fleets with fewer electric buses.
Real-World Data
Cook said key performance indicators come down to the triangle of success: Vehicle, charger and charge management system. For instance, he said, if the charger or CMS system breaks, students aren’t being transported via that bus the next day.
“It’s not just the bus, it takes three things to make the wheels go around,” he said, adding that with diesel buses it’s more than likely the bus will run every morning.
Where a challenge will come, he said, is bringing electric vehicles into cost parity with diesel, which is the industry goal. “There’s no crystal ball on funding opportunities out there. Getting it down to diesel parity is going to be tough for us,” he continued. “We don’t know what tomorrow will bring.”
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Meanwhile, Beaver, who’s been tracking and sharing the results for all the vehicles he operates on his website, said he’s getting good data on the cost to run the different vehicles. In addition to running five of the six ESB brands available, he also operates renewable diesel and renewable propane. Looking at the total cost per mile, Beaver said his district’s cost is $1.06 per mile to operate a diesel bus, 72 cents per mile for a propane bus, and 56 cents per mile to operate an electric vehicle.
“The cost numbers aren’t lying. It’s cheaper to operate electric,” he said, adding that there are non-measurable benefits as well, such as a quiet bus ride and a healthier environment for the kids.
Cook cautioned against looking solely at cost per mile, as the upfront cost of the ESB is going to be higher than that of a propane or diesel bus. Looking at the total cost of ownership and the entire picture allows one to understand both the short-term cost per mile and what it will cost in the long term, he added.
