Used Waymo robotaxi batteries become backup storage for power grids
Source: Ars Technica
EV Circle of Life
Used Waymo batteries will bolster California and Texas energy‑storage projects.
At SEPV Sierra (Lancaster, CA)
32 MWh of energy storage paired with 8 MW of solar power supports the local grid.
Credit: Awarded Goods Company
Why Waymo’s batteries matter
Thousands of electric vehicles in Waymo’s autonomous robotaxi fleet may eventually give up their used batteries for a very different purpose—contributing up to hundreds of megawatt‑hours of stationary energy storage to local power grids.
The prospect comes from a strategic supply agreement announced by Waymo and B2U Storage Solutions on June 4. B2U has been repurposing thousands of used batteries from various EVs by installing them in large stationary storage projects. Such facilities can capture excess renewable energy during low‑demand periods and release it when the grid experiences peak demand.
“Our business is getting the full residual value out of electric‑vehicle batteries after they’re no longer suitable for automotive use,” said Freeman Hall, CEO of B2U Storage Solutions, in an interview with 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’s “proactive maintenance” program identifies opportunities to refresh batteries to improve fleet efficiency. When a battery is swapped out, it can be redirected to second‑life applications, because “there’s still a lot of life left in the battery,” explains Adam Lenz, Head of Sustainability & Environment at Waymo.
Battery degradation in Waymo’s fleet
- Waymo robotaxis drive far more each day than typical consumer EVs, leading to faster usage‑related degradation.
- A 2025 analysis of 22,700 EVs across 21 models (Geotab) found an average capacity loss of ~2.3 % per year, meaning batteries retain >81 % of original capacity after eight years.
Waymo’s current fleet (~4,000 vehicles) mainly consists of Jaguar I‑Pace EVs with 90 kWh lithium‑ion batteries. The company is also rolling out the Ojai robotaxi from Zeekr, equipped 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 added.
Potential storage capacity
Given the fleet size and battery capacities, the repurposed batteries could provide large megawatt‑hour numbers for stationary storage, supporting power grids in California, Texas, and beyond.
- B2U already receives initial small quantities of Waymo batteries.
- Over time, the agreement could deliver hundreds of megawatt‑hours of additional storage capacity, according to Lenz.
Key takeaways
| Aspect | Details |
|---|---|
| Agreement | Waymo ↔ B2U Storage Solutions (strategic supply) |
| Current fleet | ~4,000 robotaxis (Jaguar I‑Pace 90 kWh, Zeekr Ojai 93 kWh) |
| Battery health | ~2.3 % capacity loss per year (Geotab study) |
| Potential repurposed capacity | Hundreds of MWh (over time) |
| Geographic focus | California & Texas energy‑storage projects |
References
- Waymo press release, June 4, 2026.
- Ars Technica interview with Freeman Hall & Adam Lenz.
- Geotab, “EV Battery Health,” 2025.
- Nature Energy, “Usage‑related degradation in EV batteries,” 2024.
- Waymo blog, “Welcoming riders in the Ojai,” May 2026.
Local Grid Synergy
The B2U grid‑storage solution could do more than simply extend the usefulness of lithium‑ion batteries from Waymo’s fleet by several years. 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.
“What we think is really cool and unique about this opportunity is that these are the batteries that are helping serve our riders in these communities, and then they’re actually going to B2U to then be deployed in local grids that are near communities that we serve as well,” Lenz told Ars. “So there’s a nice circularity here for our commitment to clean technology and supporting renewable energy on the grids.”
Used Waymo batteries will be received at B2U’s Lancaster facility in Los Angeles County, which already houses more than 1,300 repurposed electric‑vehicle batteries (Ars Technica source). From there, the batteries will be deployed to other B2U energy‑storage projects across California and Texas, including a 24 MWh storage project in Bexar County, Texas, that could support Waymo’s growing deployment in San Antonio.
The all‑electric fleet of Waymo robotaxis prevents 530 tons of CO₂ emissions with every 500,000 weekly trips, according to company estimates. Waymo typically sources the electricity required for charging its vehicles from local wind and solar generation projects and sometimes purchases renewable‑energy certificates to cover any gaps (methodology PDF).
One exception to that clean‑energy prioritization has been Waymo’s partnership with ride‑hailing giant Uber in Austin, Texas. Uber installed a “temporary charging solution” for Waymo vehicles serving Austin riders that involved mobile L‑Charge generators running on natural gas, which subsequently drew local attention (Yahoo article) and complaints (Statesman article) because of the generator noises.
In any case, Waymo’s agreement with B2U fits with a broader trend of the United States installing record amounts of battery energy storage. A report by the Solar Energy Industries Association showed that U.S. stationary‑storage installations reached 9.7 GWh in Q1 2026—the “largest Q1 in history” and a 32 % year‑over‑year increase (SEIA report).
B2U is already managing more than 4,000 EV battery packs across its projects, including used Nissan Leaf batteries first installed in 2020 that are still going strong after roughly 2,500 cycles. “We have a nice supply of batteries, but it’s great to add to this supply because the demand for storage is very high,” said Hall.
This article was updated on June 4, 2026 to correct a misspelling of the company name B2U.
Jeremy Hsu is a reporter exploring a wide range of topics across deep tech and AI. He has previously written for New Scientist, Scientific American, IEEE Spectrum, Wired, Undark Magazine, and MIT Tech Review, among many other publications, covering deepfakes, data centers, drones, battery tech, robotics, and GPS jamming. He holds an M.A. in Journalism from NYU and a B.A. in History and Sociology of Science (minor in English) from the University of Pennsylvania.
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