As record-breaking heat waves sweep across much of the United States this summer, more than 200 electric school buses are providing a novel source of power to help ease stress on regional electricity grids. With schools closed for the season, the electric buses—equipped with large batteries—are sending stored energy back to local utilities through emerging Vehicle-to-Grid (V2G) technology.

Spanning from California to North Carolina, these yellow electric buses are part of a growing network that demonstrates how electric vehicles could support the grid during peak demand periods. Currently, around 230 of the nation’s approximately 6,700 electric school buses have V2G capabilities, able to collectively supply about 8 megawatt-hours of electricity at any given time, according to the World Resources Institute’s Electric School Bus Initiative. While this is a small fraction compared to the 160,000 megawatts PJM, the country's largest regional grid operator, requires to meet high demand for 67 million people, experts see considerable potential for growth in the coming years.

“These are very early days,” said Steve Letendre, senior adviser to the Vehicle Grid Integration Council trade association. “School buses will be a critically important backbone of V2G capacity.” Electric school buses typically have battery capacities exceeding 200 kilowatt-hours and can be charged during low-demand periods before feeding power back to utilities during peak hours. Since many school buses sit idle during the summer months—when electricity demand often surges—the integration of V2G technology can provide a crucial resource for managing grid stability.

At present, more than 31 utilities and 21 states are involved in V2G school bus projects. The number of electric school buses is expected to more than double to approximately 14,625 nationwide within the next few years, representing about 3% of the entire school bus fleet, with many of these vehicles designed to be V2G-enabled.

Despite the promise, the technology faces several challenges. Initial costs for V2G infrastructure can be significant, and a lack of universal standards or regulatory frameworks complicates widespread adoption. Battery owners and operators remain concerned about potential accelerated battery wear caused by frequent charging and discharging cycles, and some worry that participating in V2G programs could void warranties.

Critics of vehicle electrification and publicly funded alternative energy initiatives also argue that increased electric vehicle use might strain the power grid. In response, many school districts are incorporating solar energy for bus charging to offset potential impacts.

California is leading national efforts to expand V2G school bus technology. The state’s largest program is with Oakland Unified School District, where a collaboration between Pacific Gas & Electric and transit provider Zum operates 74 electric buses that generate an estimated 2.1 gigawatt-hours annually. A separate Zum project with the San Francisco Unified School District, launching next month, is projected to exceed that output with an initial fleet of 104 buses, expected to produce roughly 3 gigawatt-hours during peak periods each year. By 2027-2028, this fleet is slated to grow to 238 vehicles. California’s mandate requires that electric school buses funded through state programs have V2G capabilities, supported by investments in infrastructure and partnerships with major utilities PG&E and Southern California Edison.

Elsewhere, the Branford Public Schools district in Connecticut will introduce 46 V2G-capable electric buses in August. In North Carolina, Cherokee Boys Club operates 21 electric school buses for Cherokee Central Schools under a V2G pilot program funded by Duke Energy. Donnie Owle, service manager for Cherokee Boys Club, highlighted ongoing efforts to use the buses as emergency power generators for school buildings designated as shelters.

In Florida, while funding for V2G programs is not yet secured, Daniel Thomas, director of administrative services for Glades County School District, plans to use 13 Blue Bird electric buses as mobile cooling centers during hurricanes, emphasizing the buses’ potential role in emergency preparedness as well as grid support.

As electric school bus fleets expand and V2G technology matures, experts and school districts are exploring diverse applications that may help bolster power resilience amid extreme weather and rising electricity demand.