Are electric school buses right for your district? |
On Board Online • July 5, 2021
By Paul Heiser
Senior Research Analyst
The Bethlehem Central School District in Albany County has plans to convert its entire 132-bus fleet to all electric vehicles. The district took its first step toward that goal on May 18, when voters approved a proposition to purchase up to five electric buses for the 2021-22 school year.
Bethlehem thus became just the second district in New York to experiment with electric school buses. In 2018, the White Plains City School District added five electric buses to its fleet of 80 as part of a pilot program. According to Superintendent Joseph Ricca, the experiment has been a hit with students and staff alike.
"They were very well received right out of the gate," Ricca told On Board. "Great seating, lights, climate control, no emissions, silent, kids love them, so much so that the district alternates the buses so that they go through different neighborhoods. There have been no drawbacks so far."
For decades, school districts have relied almost exclusively on diesel buses to transport kids to school and home, and diesel remains the dominant technology of the approximately 45,600 buses in operation across the state. The reason, according to Allen Schaeffer, the executive director of the Diesel Technology Forum, a non-profit organization that advocates for diesel technology, is that diesel buses are relatively inexpensive, safe and durable.
Like many new and emerging technologies, electric buses have been slow to catch on in New York. Questions exist over their cost, maintenance and reliability. According to David Christopher, the executive director of the New York Association for Pupil Transportation, "Our members embrace electric buses in concept and understand that electric vehicles are on the horizon. The hesitancy in implementation is the cost. There are also concerns regarding infrastructure, battery life, bus fires, and range of operation."
What follows is an analysis of the benefits and drawbacks of electric school buses compared with diesel school buses.
Initial high cost, followed by savings
Perhaps the biggest barrier to widespread electric school bus use is cost. The initial purchase price of an electric school bus is as much as three to four times that of a diesel school bus. According to Randall Ray, the new business director for IC Bus headquartered in Lisle, Illinois, electric school buses can cost up to $350,000 to $400,000, compared with $100,000 for a diesel bus.
"That is the biggest challenge in turning over a school bus fleet wholesale," said Ricca, the White Plains superintendent. He called the initial purchase price of electric school buses an "enormous outlay."
White Plains partnered with the Lion Electric Company, a Quebec-based manufacturer of electric school buses, and British public transportation company National Express to deploy five school buses. The New York State Energy Research and Development Authority (NYSERDA), Con Edison and National Express all contributed to the purchase of the electric bus fleet, while National Express pays for the energy costs during the school year.
Bethlehem's purchase of electric buses is contingent on grant funding from NYSERDA, which has the authority to award up to five $200,000 grants ($1 million in total).
"We are waiting for their decision, and plan to purchase as many electric buses as they fund," said Judi Kehoe, Bethlehem's business manager. "We hope that will be the maximum of five."
Other cost considerations include building infrastructure for charging, operational costs and maintenance.
After the initial purchase, districts can generally expect to save on their operating costs with electric school buses in the form of fuel savings and lower maintenance costs.
"While your capital costs go up, your operating costs go down," Ray told On Board. "In fact, your operating costs drop on day one."
For starters, fuel costs for electric buses fall to zero, replaced with the costs of charging. According to School Transportation News, with the cost of electricity around 60% lower than diesel, an electric school bus could save schools nearly $2,000 a year in fuel costs. In addition, expect no costs associated with oil changes, oil level, belts, coolant, radiator fluids and fuel injectors. Electric buses also tend to exert less wear and tear on the brakes through regenerative braking systems. Unlike with a traditional braking system where brake pads produce friction with the brake rotors to slow or stop the vehicle, regenerative brakes slow the vehicle by causing the motor to operate in reverse.
But Ray cautions that operation and maintenance cost savings likely won't make up for the initial cost of the bus. "Electric has to come down to about $200,000 to pay for itself, because savings amount to about $100,000 in fuel and maintenance [over the life of the bus]," he said.
Environmental factors involve tradeoffs
Unlike diesel buses, electric school buses have no tailpipe emissions because they run entirely on battery power. But according to Schaeffer of the Diesel Technology Forum, diesel buses are much cleaner than they once were. That's because all pre-2011 school buses in New York have been phased out, and newer buses are equipped with particulate reduction technology. "School buses account for a tiny sliver of greenhouse admissions. They travel very few miles with small cargo loads," he said.
Based on data generated from the Environmental Protection Agency's Diesel Emissions Quantifier tool, emissions from a 2021 model diesel bus are almost as low as those of an electric bus in four out of five categories of pollutants - nitrogen oxides, particulate matter, hydrocarbons and carbon monoxide. The one category in which diesel buses produce significantly more emissions is carbon dioxide.
Shaeffer also points out that the power for electric bus batteries comes from the power grid, which involves emissions at the power generating facility. "If you're using coal as your charging source, you're negating much of the emissions advantage you have with electric buses," he said. Furthermore, using 100% renewable diesel fuel, made of animal and waste products, rather than petroleum diesel can cut emissions by 50-80%, he said. "Changing fuels is the fastest way to reduce climatic impact," he said.
Limited range of electric vehicles
Aside from cost, perhaps the biggest disparity between electric and diesel buses is range. According to Ray from IC Bus, electric buses can travel about 100-120 miles on a single charge, depending on the manufacturer, driver behavior and operating conditions. By comparison, diesel buses can travel about 700-800 miles on a single tank of fuel (assuming a 100-gallon tank that gets 7-8 miles per gallon).
Ray said that while the range for electric buses should be okay for most districts whose buses make relatively short trips, it can give others "range anxiety," especially if their buses are used for field trips or sporting events. However, newer batteries and advanced technologies are currently in development, which may provide extended range at a lower cost.
Driver and technician training
Another factor when considering the acquisition of electric buses is any additional technician and driver training that may be required. According to School Transportation News, while maintenance is significantly decreased with electric school buses because of far fewer moving parts in the motor, technicians still will need to be well-versed in how to safely service an electric school bus. Drivers will need not only to be aware of how to drive an electric school bus, but also how to charge it safely. Bus manufacturers typically provide technician and driver training, along with expert resources for advanced electrical troubleshooting and maintenance.
Building infrastructure for battery charging
Charging infrastructure must be carefully planned, based on routes and battery range. According to Ray, districts need to account for how much power they have coming into their existing facilities and how much power they are currently using for other activities. For example, if you have an older facility in which welders are working, then the amount of power coming into the building may not be sufficient to charge electric vehicles.
The length of time it takes to charge an electric bus battery must be factored in as well. Charge time is based on the output of the charger, the size of the unit being charged and ambient factors such as hot and cold weather. A commercial-grade charger takes about 10 hours to fully charge a bus battery. Warming and managing the battery will also use some of that charging capability.
On the plus side, an electric bus, when plugged in, will charge only when and if needed, thanks to recent charging infrastructure advancements. Chargers can be programmed to charge the school bus during the times of day when energy costs are least expensive.
Some electric school buses, known as vehicle-to-grid (or V2G), allow electricity to flow from the bus back to the electric grid when parked. That energy can then be distributed to customers. According to Electrek, an American news website dedicated to electric transportation and sustainable energy, V2G works well for school buses because they have a lot of battery space and significant non-operational time when they are parked and plugged in, such as nights, weekends, summers, and holidays.
Operation: 'Like driving a 40-foot golf cart'
According to Ray, electric buses are a joy to operate because they run smoothly and are very quiet. "Drivers love them," he said. "They are quiet as a church mouse, like driving a 40-foot golf cart. It provides the added benefit of being able to hear the children on the bus, and the town is going to like not hearing the bus at seven in the morning."
Ray noted that diesel buses are much quieter than they used to be; injection technology provides the precise amount of atomized and pressurized fuel into each engine cylinder at the proper time, increasing efficiency. He also noted that quiet vehicles can pose a danger in that pedestrians can't hear them coming. He said sound generators are not yet required on electric buses, but the industry is moving toward making them standard.