The Waymo robotaxi’s used batteries serve as storage for the power grid

A 2025 study of more than 22,700 electric vehicles across 21 brands found that battery loss was about 2.3 percent per year, according to telematics company Geotab. This means that such batteries still have more than 81 percent of their original capacity after eight years.

Waymo’s current fleet of nearly 4,000 vehicles mainly consists of Jaguar I-Pace electric vehicles with a 90 kWh lithium-ion battery. The company also started selling products Oh, robots made by Chinese car brand Zeekr with a 93 kWh battery.

“Put a hair down in terms of degradation and the good power that can be left in those batteries by the time they’re worth recharging, and we’re talking about battery life,” Hall said.

Waymo’s growing robotaxi fleet could bring “very large numbers in terms of the number of megawatt hours that can be deployed very quickly” to store standby power to support the power grid, he said.

The agreement gives Waymo control over when and how many batteries will be shipped to B2U. But the company confirmed that B2U has “already started receiving small batteries” from Waymo’s fleet. Over time, the partnership could give B2U “hundreds of megawatt-hours” of additional storage from Waymo’s thousands of electric vehicles, Lenz said.

Local grid connection

The B2U grid storage system could do more than just increase the demand for lithium-ion batteries from Waymo’s fleet in a few years. The new agreement aims to support B2U projects in sections where Waymo’s robotaxis work – meaning that used Waymo batteries can power the local power grids that Waymo’s vehicles rely on to charge.

“What we think is great and unique about this opportunity is that these are batteries that are helping riders in these areas, and then they’re going to BTU to be sent to local communities that are close to the areas that we serve as well,” Lenz told Ars. “So there’s a virtuous cycle here in our commitment to clean technology and support renewable energy on the grid.”