A bus that earns $12,000 a summer rewrites the fleet math

Across the summers of 2021 and 2022, one electric school bus in the Boston suburbs discharged about 10.8 MWh into the local distribution grid to offset load peaks, and National Grid's ConnectedSolutions virtual power plant paid close to $12,000 a season for the work. The revenue belongs to a vehicle a district bought for another job entirely, which is why it matters to anyone weighing the upfront premium of an electric bus against a diesel one.

That single-bus result has not scaled. At least 26 utilities and 19 states have enacted V2G programs that let bidirectional passenger and commercial vehicles push power back for demand response, ancillary services and other purposes, according to the World Resources Institute's Electric School Bus Initiative, while U.S. districts have more than 230 V2G-enabled buses in service and hundreds more on the way. Set against the more than 14,000 electric buses districts have committed to—in use or planned across upwards of 1,550 of them—the V2G fleet is a sliver.

The Beverly pilot is now the smaller half of the Massachusetts story: Elijah Sinclair, senior program manager for clean transportation at the Massachusetts Clean Energy Center, told Utility Dive the pilot was "crucial proof" and that MassCEC's broader vehicle-to-grid pilot has grown past 20 buses, with other commercial vehicles and private light-duty cars mixed in, carrying tens of millions of state dollars behind it.

California holds much of the V2G fleet, anchored by the 74-bus deployment Zum operates for Oakland public schools, each bus paired with its own bidirectional charger and the group supporting 2.1 GWh of annual discharge, according to PG&E. Rudi Halbright, a PG&E product manager who supports the utility's vehicle-to-grid pilots, told Utility Dive the steadiest money runs through the Emergency Load Reduction Program. "What's the value of keeping California out of brownouts and blackouts?" he said. "That's where they make the most guaranteed revenue."

Where the revenue lands matters as much as the amount. Deployments can pay districts or fleet owners, and on the biggest one the buses belong to a contractor working on a district's behalf, which suggests the grid-services margin sits on the operator's books rather than the school's. Beverly also flatters a single, well-sited bus inside a pilot with every reason to make it work; whether $12,000 a season survives at the scale of a 74-bus depot is what the Oakland fleet is actually testing.

School buses are the kind of distributed resource a utility can enroll a depot at a time rather than a house at a time, and as this publication argued when Google put money behind PG&E's residential virtual plant, what a utility buys in these programs is coordination rather than construction. Districts buying bidirectional chargers run the same trade from the other side, turning a hardware premium into an offset against a purchase price that still exceeds diesel, but the charger gets ordered before the bus does, and that decision rests on what the tariff pays and for how long. Beverly proved one bus can earn. Whether the committed 14,000 follow depends on terms the other utilities have not yet had to publish.