By Ryan Gerrity
School buses generally come in large fleets, powered almost exclusively by diesel fuel, making them an important potential component of a public strategy to reduce greenhouse gas emissions, improve air quality and improve health. In Vermont alone, there are over 1,800 diesel buses transporting more than 75,000 children every school day. The New Hampshire school bus fleet has 2,900 buses and transports over 175,000 children. These buses release exhaust containing carcinogens, particulates, and pollutants known to cause issues such as facial irritation, respiratory inflammation, higher susceptibility to allergens or even serious health problems such as reduced lung function, asthma attacks, heart disease and lung cancer. Considering these issues, school buses are a great candidate for electrification.
The Vermont Energy Investment Corporation’s Transportation Efficiency group has studied the feasibility of electric transit buses in Vermont and is currently working on an electric school bus demonstration project in four Massachusetts school districts. This article shares some of the opportunities and challenges that need to be addressed for greater adoption of electric school bus technology.
Electric school bus technology is becoming more accessible, creating a growing opportunity for school districts in the Northeast to transition to clean, zero-emission vehicles. Companies like TransPower in California and Lion Bus of Canada are already making electric school bus components and fully functional buses. Through these companies, you can retrofit a used bus with electric drive components, or buy a new, purpose-built electric school bus, making it possible to convert diesel school buses to all-electric today.
Electric vehicle technology still has a higher upfront cost than a diesel vehicle, but there are many opportunities for savings over time which can offset this initial investment. For example, the number of components found in an electric drive system is only a fraction of the amount found in a diesel engine which means no oil changes and dramatically less maintenance needed in general. Electric drive systems can save on average, upwards of $10,000 annually on maintenance.
Lower fuel costs are another benefit of electric school buses. Electricity rates are relatively consistent compared to the pricing of diesel and other conventional fuels and an electric school bus can be powered with electricity equivalent to about $1.25 per gallon of fuel. Costs for charging electric school buses can potentially be further mitigated with time of use rates that encourage charging during off-peak hours.
Buses equipped with bi-directional charging technology also have the potential to offer a vehicle to building (V2B) and vehicle to grid (V2G) service. With this technology, buses could supply schools with electricity to avoid drawing from the grid at peak rates, to save money, or provide relief to the grid when peak rates are present. A utility partnership where buses provide grid reliability services during peak electricity usage times has the potential to generate revenue while the buses are not being used for student transportation. While this application is not yet readily available, it has the potential to add an entirely new functionality, and value to school buses.
Perhaps the greatest opportunity for electric school buses is to provide clean transportation for our children and protect them from exposure to dangerous particulates in diesel fumes. Unlike diesel buses, plug-in electric school buses have no tailpipe emissions. In addition to eliminating the health risks to children riding school buses, we can generally improve air quality in communities and help reduce our greenhouse gas emissions which contribute to climate change.
The main challenge for mass adoption of electric school buses is cost. A new diesel bus typically costs $90,000. The cost of an electric school bus is around $350,000, which includes charging infrastructure purchase, installation and basic software. Public funding is available to help defray the costs of replacing diesel school buses through the Diesel Emissions Reduction Act (DERA) passed in 2005. This program provides funding for replacing outdated diesel vehicles and improving diesel vehicle engines to reduce emissions. As technology improves and more school buses are deployed there will be more opportunities to reduce costs. With this in mind, electric school bus fleets may become more common in the near future.
Ryan Gerrity is an outreach coordinator for Drive Electric Vermont.