Lessons from Electric School Bus V2G Programs

The field of electric school bus (ESB) vehicle to grid (V2G) programs is rapidly evolving. The number of V2G programs across the U.S. continues to grow: At least 11 utilities and five states have enacted programs since we first examined the space two years ago, bringing the totals to 26 utilities and 19 states. This still-evolving technology is helping increase the adoption of and excitement around ESBs. And it is proving their potential as grid assets at a time when increased storms, wildfires and extreme heat, as well as increased load, are adding stress to the current power system.

However, various financial, technological and operational hurdles will need to be addressed for this progress to continue. Based on interviews with utilities, school districts and ESB operators that are making V2G happen across the country, this article offers updates, lessons learned and examples from the field.

Map of Utility V2G Electric School Bus Pilot Programs

See a full table of ESB V2G programs across the United States here.

Key Takeaways

• ESB V2G is working in several locations, helping support community resilience and lower energy costs for schools. But real-world experience is still limited.
• Utilities are testing the limits of V2G options and finding ESBs can consistently provide V2G services on demand at their full power output over several hours.
• Deploying technology at scale requires interoperability and cooperation between ESB operators, utilities and equipment manufacturers.
• Utilities can support more V2G adoption by leading with supportive rates, policies and education.
• V2G can be a resource for rural co-ops, municipal utilities and other actors outside of deregulated markets and investor-owned utilities who want to be proactive in managing their system demand.
• Beyond V2G, ESBs can provide additional services to their communities, such as dispatchable power for emergency facilities.

How Electric School Bus Vehicle-to-Grid Projects Work

ESBs are a predictable and mobile source of energy demand and supply. During regular operation, they are reliably plugged in and charging in the middle of the day and overnight. In the summer when ESBs are less active, or in cases where their routes are short enough to have energy leftover, they can then be called on to push energy back onto the grid. Deploying ESBs as a clean and flexible energy source is one way to help reduce reliance on fossil fuels and lower overall electricity costs, as well as reduce dangerous diesel pollution. In addition, in an outage or disaster situation, ESBs could be deployed where needed to provide backup power to the community.

That said, there are two crucial things to keep in mind when approaching any ESB V2G project:

ESBs are, first and foremost, school buses. While they offer opportunities for grid-connected and site-powering electricity storage, we must ensure that these vehicles are available for their primary purpose of student transportation.

ESBs do not act in the same way as stationary storage. Depending on the manufacturer’s specifications, distance traveled, route topography and weather, an ESB might not have enough power remaining to discharge energy back to the grid in the afternoon and evening on days it is in service. Instead, school bus operators can be sure to keep their charging off peak to reduce their demand on the local system.

Ongoing Challenges for ESB V2G

While ESBs are already providing V2G services across the country, there are several impediments to widespread adoption. From our interviews and outreach, some of these barriers include:

• Concern over ESB battery life and warranty when providing V2G services.
• Compensation mechanisms for the energy provided to the utility.
• The increased cost of V2G-capable infrastructure compared to other electric vehicle supply equipment (EVSE).
• Technology issues with interoperability between different ESBs and EVSE.

Addressing these issues requires continued collaboration between utilities, equipment manufacturers, technology companies, transportation providers and school districts to build a stronger and more sustainable V2G ecosystem.

Program Highlights

ESB V2G can work in any area, with any combination of school transportation models (public or private) and utility environment (investor-owned, municipal or cooperative). Successful ESB deployments have been characterized by their clear intent to participate in V2G from the outset; specific localized goals for their development; and robust value frameworks and financial incentives to guide their structures.

The examples below explore how some stakeholders are beginning to address common challenges and scale up local V2G efforts. A few of these leaders are showing how ESBs can engage in V2G services at a larger scale to support local grid stability, reduce operations costs for school districts and utilities, and provide emergency resilience for communities.

Electric school buses in action: El Cajon, Calif.

As we covered in a recent case study, the Cajon Valley Union School District (CVUSD) is on the leading edge of ESB V2G. The school district has been working on the project in partnership with its local utility, San Diego Gas and Electric (SDG&E), for more than three years. Today, its electric school buses regularly provide power back into the local grid when requested.

This has primarily been done through California’s Emergency Load Reduction Program (ELRP), which aims to avoid outages by paying electricity customers to reduce consumption or increase supply during peak demand times. Under the program, CVUSD can provide demand reduction and energy dispatch for one to five hours at a time when events are called, which happens around 10 times per year. They are compensated $2 per kWh for their energy dispatch. The process uses six bidirectional chargers rated to 60kW, and ESBs with batteries containing around 180kWh.

Through this program, the Cajon Valley school district has been able to help support the local power grid and lower the district’s energy costs – while the ESBs continue to serve students’ needs.

Local utility control: Durango, Colo.

Municipal utilities and rural co-ops do not have the same market structures to incentivize ESB V2G as investor-owned utilities. Nevertheless, they are also forging ahead with projects focused on their biggest need: peak demand shaving.

Many municipal and co-op utilities purchase power from transmission operators rather than generating their own power. V2G projects allow them to lower the maximum amount of energy required to operate their system and space out the amount of energy they provide over time. This means lower costs for energy, increased ability to utilize renewables like solar, and less reliance on expensive and polluting fossil fuel generation.

One such utility is La Plata Electric Association (LPEA) which has partnered with Durango School District 9-R in Colorado to deploy ESB V2G. After initial failures with its technology platform, LPEA worked with other technology providers to build out a software system giving it better control over the power dispatch from the ESBs. This has allowed LPEA to better integrate the V2G project into its distribution system, making it easier for the utility to accept energy discharged by the buses.

LPEA’s challenges highlight continued technology hurdles and the need to focus on building a robust, generalized ESB V2G system that can integrate well with electrical utilities.

Developing compensation: Northeast US

As ESB V2G projects expand beyond the pilot stage toward wider deployment, the question has arisen of how to compensate operators for electricity they deploy. Projects across the Northeast United States offer examples of how supportive rates and policies, or lack thereof, can make or break a V2G project.

In Beverly, Mass., Highland Electric Fleets can take advantage of National Grid’s Connected Solutions program. This compensates the bus operator for power provided over the summer months at $200 per kW delivered during peak demand events, averaged over the summer. While this is valuable compensation (around $6,000 per vehicle per year), being confined to a few events over the summer means it will not always cover the cost of the more expensive equipment required for V2G.

South Burlington, Vt. and White Plains, N.Y. take advantage of year-round incentives through Green Mountain Power’s Flexible Load Management program (around $9,000 per vehicle per year) and ConEd’s Value of Distributed Energy Resources program (compensated at the reported actual cost to the utility), respectively. These programs offer consistent compensation based on the condition of their local grid, giving them stable value to help provide additional support to their projects.

Meanwhile, the Wells-Ogunquit School District in Maine has put its V2G pilot on hold while it establishes a compensation scheme with the local utility and its regulator, demonstrating the need to have clarity on compensation.

Passing the test: West Linn, Ore.

While V2G continues to develop, utilities are working to understand its value for their local grids and see how it might complement existing demand response programs. Portland General Electric has been an early leader in the field and is working with First Student to test the potential of their ESBs to feed power onto the grid during peak times. Portland General Electric has been conducting a demonstration with a 60kW bidirectional charger and a 155kWh bus. Over the summer of 2024, the bus was put through tests to deliver stable power output over three-hour events. Having collected valuable learnings from its demonstration, Portland General Electric is optimistic about expanding its demonstrations to include additional bus and charger combinations.

Deploying at scale: Oakland, Calif.

Moving to more numerous ESB deployments requires far more coordination than just a handful of buses, especially when V2G is involved. One such deployment that made headlines has been Zum’s partnership with Oakland Unified School District and Pacific Gas and Electric (PG&E), which has deployed a large-scale V2G enabled school bus yard. With more than 70 ESBs with 150kWh batteries hooked up to 30kW charging equipment, Zum can deploy more than 2MW in response to the same ELRP events as Cajon Valley described above.

The key to this deployment, beyond extensive coordination with the local utility, was ensuring that the district’s chargers and vehicles were ISO 15118 compliant. The focus of this technical standard seeks to ease the deployment of vehicles and chargers that are interoperable. Rather than needing to test specific vehicles and chargers, standardization ameliorates common issues from V2G project deployment and has allowed Zum to achieve scale with its rollout.

Boosting resilience: Hood River, Ore.

ESBs also have a role to play providing energy benefits to their communities beyond V2G. As part of the MOVER project (Microgrid Opportunities: Vehicles Enhancing Resiliency), the Hood River County School District in Oregon has partnered with the New Buildings Institute to utilize its ESBs as emergency resources. Rather than feeding into the grid, these buses will be used to provide power directly to Wy’East Middle School in emergency situations as part of a local microgrid that can still be powered and operational if there is a grid outage.

What We’ve Learned from National ESB V2G Programs

ESBs are on the road delivering clean rides for students while supporting their local grids with V2G. Electrifying fleets can offer megawatts of on-demand power to communities and the utility grids that serve them. But to fully realize this potential, we need more collaboration and communication around ESBs and V2G to work through existing issues of technology, cost and compensation. By learning from each other’s challenges and successes, we can not only lower energy costs and carbon emissions, but also help build safer communities and pave the way to a clean ride for kids.