As a blistering heat dome settled over much of the United States last week, pushing power grids to the brink of failure, a familiar narrative resurfaced: the surging number of electric vehicles would only add to the strain. The data now tells a strikingly different story. Instead of draining the grid, a growing fleet of electric school buses equipped with vehicle-to-grid (V2G) technology did the exact opposite—they fed power back into the system, helping utilities keep air conditioners running and lights on during the most critical hours.
The World Resources Institute’s Electric School Bus Initiative reports that roughly 230 electric school buses deployed across several V2G projects are now capable of supplying 8 megawatt-hours (MWh) of electricity to the grid at any given moment. That is enough stored energy to power approximately 1,600 typical American homes for up to four hours, shaving peak load demand precisely when the grid is most vulnerable. School may be out for the summer, but these buses are working harder than ever.
How Electric School Buses Are Helping Stabilize the Grid During Heat Waves
The mechanism is straightforward yet transformative. During off-peak hours—typically overnight or mid-day when electricity demand is low and renewable generation is abundant—the buses charge their batteries. When demand spikes, as it did during the recent heat wave, utilities can draw power from those same batteries rather than firing up expensive and often dirty peaker plants. This bidirectional flow, known as vehicle-to-grid or V2G, turns a parked school bus into a distributed energy resource.
“It’s very early days,” said Steve Letendre, senior advisor to the Vehicle Grid Integration Council, “but school buses will be a critically important backbone of V2G capacity.” The logic is compelling: school buses have predictable schedules, large battery packs, and spend most of their time parked—making them ideal candidates for grid services.
California Leads the Nation in V2G School Bus Deployment
California has emerged as the undisputed leader in developing and deploying V2G-capable school buses. The state’s largest project, operated by the Oakland Unified School District, manages a fleet of 74 electric buses that collectively return an estimated 2.1 GWh of clean energy to the grid each year. That is enough electricity to offset the annual consumption of hundreds of homes and provides the local utility with a flexible, zero-emission resource during peak periods.
The Oakland project, developed in partnership with Zum, has become a template for what is possible. It demonstrates that V2G can work at scale, under real-world conditions, and deliver measurable benefits to both the grid operator and the community. Other districts across the country are now watching closely.
What is vehicle-to-grid (V2G) technology and how does it work with school buses?
Vehicle-to-grid technology allows electricity to flow both ways: into the battery from the grid and back out from the battery to the grid. When a school bus is plugged into a bidirectional charger, it can either charge during low-demand periods or discharge during high-demand periods. Utilities compensate school districts for the power they supply, creating a new revenue stream that can offset the higher upfront cost of electric buses. The bus fleet essentially functions as a virtual power plant.
Beyond 8 MWh: The Remarkable Scaling Potential of School Bus V2G
The 8 MWh currently available from 230 buses is impressive, but it represents only a fraction of what is possible. Consider the arithmetic: if 230 electric school buses can deliver 8 MWh of energy back to the grid, scaling that to just half of the roughly 6,700 electric school buses already on US roads would yield well over 100 MWh of flexible, off-peak energy available during periods of peak demand. That is enough stored capacity to power tens of thousands of homes for hours.
That kind of resource flexibility does not just shore up the existing grid—it fundamentally changes how utilities think about peak load management. Every megawatt-hour of energy drawn from a school bus battery during a heat wave is one less megawatt-hour that has to be purchased on the wholesale energy market at emergency prices.
Lower Electricity Bills and Greater Grid Resilience for Consumers
Fewer emergency power purchases mean lower transmission and delivery costs for utilities, and those savings can ultimately flow through to ratepayers. The economic case for V2G is becoming as strong as the environmental case. By reducing the need for peaker plants—which are typically natural gas-fired and among the most expensive power generation assets to operate—V2G programs can put downward pressure on electricity prices for everyone, not just the school districts that own the buses.
And the benefits extend beyond economics. The ability to tap into battery-stored power during emergencies can be a literal lifesaver. “If we have a hurricane, and God forbid we do, but if we do and there’s no power in the community, we can bring our buses to specified locations and the community can charge their phones,” said Angie White-Banda, transportation supervisor for Florida’s Glades County School District. “They can charge their devices. They can come in with, and sit down for a little while and cool off with cold AC.”
For communities vulnerable to extreme weather events, a fleet of V2G-equipped buses represents a mobile, distributed backup power system that can be deployed wherever it is needed most.
San Francisco’s Upcoming Project Signals the Next Phase of Growth
The trajectory is clear. As if to illustrate the point, San Francisco’s Unified School District is set to launch a new electric school bus project next month that is expected to surpass the Oakland project in scale. The initial deployment will include 104 buses, returning approximately 3 GWh of energy annually during peak hours. And that is just the beginning: the district plans to double the fleet to more than 238 electric buses by 2028.
This growth is not happening in isolation. School districts in New York, Massachusetts, Colorado, and Texas are all advancing V2G pilot programs. The technology is moving from demonstration phase to operational reality, driven by declining battery costs, improved bidirectional charger availability, and growing recognition that school buses offer a uniquely valuable grid asset.
The Bigger Picture: Why School Buses Are the Ideal V2G Platform
School buses possess several characteristics that make them exceptionally well-suited for vehicle-to-grid applications. Their daily routes are predictable and relatively short, meaning they return to the depot with significant remaining battery capacity. They operate on a schedule that aligns naturally with grid needs: buses are typically parked during the late afternoon and early evening—exactly when residential electricity demand peaks during a heat wave. And because school districts are public entities, the revenue from V2G services can be reinvested into education and transportation infrastructure.
Furthermore, the battery packs in modern electric school buses are substantial—typically in the range of 150 to 250 kWh per bus—providing ample capacity for grid services without compromising the next day’s route. With proper management, V2G discharge cycles can actually improve battery health by preventing prolonged periods at full state of charge.
Challenges and Next Steps for Scaling V2G School Bus Programs
Despite the clear promise, significant hurdles remain. Bidirectional charging infrastructure is still more expensive and less standardized than unidirectional equipment. Utility interconnection processes can be slow and vary widely by region. And school districts need technical expertise and financial models to evaluate V2G contracts and manage the operational complexity of a bidirectional fleet.
Policymakers are beginning to address these barriers. California’s Self-Generation Incentive Program and the federal Clean School Bus Program are providing funding for both vehicle acquisition and charging infrastructure. Meanwhile, utilities are developing new tariff structures that properly compensate school districts for the grid services their buses provide. As these pieces fall into place, the economics of V2G school buses will only become more attractive.
The 8 MWh delivered during last week’s heat wave is a proof point—a concrete demonstration that the vision of electric vehicles as grid assets, not liabilities, is already operational. As Steve Letendre of the Vehicle Grid Integration Council put it, school buses are poised to become a critically important backbone of V2G capacity. The numbers, the projects, and the growing list of school districts committed to the technology all point in the same direction: we are still in the early innings, but the game has begun.
