Thousands of electric vehicles in Waymo’s autonomous robotaxi fleet may eventually contribute up to hundreds of megawatt-hours of stationary energy storage to local power grids. The prospect stems from a strategic supply agreement announced by Waymo and B2U Storage Solutions on June 4 that targets projects in California and Texas.
B2U Storage Solutions repurposes used EV batteries. B2U has been repurposing thousands of used batteries from various electric vehicles by installing them in large stationary energy storage projects. Such energy storage facilities can capture excess renewable energy during low demand periods and release such energy when local power grids are experiencing peak demand periods.
“Our business is getting the full residual value out of electric vehicle batteries after they’re no longer suitable for automotive use,” Freeman Hall, CEO of B2U Storage Solutions, told Ars. “Waymo puts a lot of miles on EVs and their model is expanding rapidly, and so we’re just very pleased and honored to be able to work with them.”
Waymo robotaxis drive around much more each day than the typical EV, which means the Waymo fleet is likely to experience faster usage-related degradation of battery capacity over time.
Waymo applies proactive battery maintenance. The agreement would allow B2U to repurpose Waymo batteries that become available at the end of a vehicle’s lifespan, along with obtaining used batteries that are being swapped out from operational vehicles. Waymo’s “proactive maintenance” for its autonomous vehicles includes identifying opportunities to “refresh the battery to improve efficiency overall for our fleet,” Adam Lenz, head of sustainability and environment at Waymo, told Ars.
“That’s when we look to these second-life applications, because there’s still a lot of life left in the battery,” he said. Waymo did not specify the average mileage at which it swaps out batteries or retires vehicles from service.
Robotaxi fleet sees accelerated battery wear. Waymo robotaxis drive around much more each day than the typical EV, which means the Waymo fleet is likely to experience faster usage-related degradation of battery capacity over time. The company confirmed that “some of these vehicles have now been serving riders for years and have mileage beyond what a normal consumer drives.”
A 2025 analysis of over 22,700 electric vehicles across 21 models found that average battery capacity loss was about 2.3 percent per year, according to the telematics company Geotab. That translates to such batteries still having more than 81 percent of their original capacity after eight years.
The agreement would allow B2U to repurpose Waymo batteries that become available at the end of a vehicle’s lifespan, along with obtaining used batteries that are being swapped out from operational vehicles.
Fleet composition drives significant capacity. Waymo’s current fleet of nearly 4,000 vehicles mainly consists of Jaguar I-Pace electric vehicles that have a 90 kWh lithium-ion battery. The company has also begun rolling out the Ojai robotaxi made by the Chinese automotive brand Zeekr with a 93 kWh battery.
“Put a little haircut on that in terms of degradation and the effective capacity that would be left in those batteries when they’re suitable for repurposing, and we’re still talking about pretty significant capacity per battery,” Hall said. The growing Waymo robotaxi fleet could lead to “pretty large numbers in terms of megawatt hours of capacity that can be deployed pretty quickly” for stationary energy storage supporting power grids, he suggested.
Initial battery deliveries have started. The agreement gives Waymo discretion over when and how many used batteries will be turned over to B2U. The companies confirmed that B2U has “already started receiving smaller initial quantities of batteries” from the Waymo fleet.
Over time, the agreement could give B2U “hundreds of megawatt-hours” of additional storage capacity from Waymo’s thousands of electric vehicles, Lenz said. The new partnership is intended to support B2U projects in regions where Waymo’s autonomous robotaxis operate—meaning the used Waymo batteries could bolster the local power grids that Waymo vehicles rely upon for charging.
