Idle Half the Day, These School Buses Now Power Homes Instead

A school bus has an unusual schedule. It runs hard for an hour in the morning, sits empty most of the day, runs hard again in the afternoon, and then does nothing until the next morning. For an electric bus with a battery the size of several Teslas, that’s a lot of stored energy going to waste every evening.

Cherry Creek School District, outside Denver, decided to put that idle time to work. Six new electric buses in the district now double as backup batteries for the local power grid, using a bi-directional charging system that lets them send power out as easily as they take it in.

Here’s the shape of the day: the buses charge overnight, when electricity demand is lowest. They run their morning and afternoon routes as normal. Then, once the last kid has been dropped off, instead of sitting at the depot doing nothing until the next school day, they feed some of their remaining charge back into the grid, right during the window when everyone else gets home, turns on the air conditioning, and starts cooking dinner.

“This partnership works to support our environmental goals while delivering long-term operational savings,” said Jennifer Perry, Cherry Creek’s interim superintendent, at the June 3rd groundbreaking for the district’s new bus facility.

The buses and the depot upgrade needed to run them came from a $2.4 million rebate that Highland Electric Fleets, the company that manages the fleet, collected through a federal partnership. Cherry Creek didn’t pay for any of it.

The scale is still small. Highland estimates that two dozen of these buses could help the grid cover peak demand for about 100 homes; a couple hundred buses could support over a thousand. But electric school bus fleets are multiplying fast across the country, and every one of them sits parked and charged for most of the day. Cherry Creek’s six buses are a small proof that all that downtime doesn’t have to be wasted.