Used Waymo Batteries Repurposed for Grid-Level Energy Storage

Waymo, a leader in autonomous taxi services, is ramping up efforts to repurpose used batteries from its vehicles for stationary energy storage systems. On June 4, the company announced a strategic supply agreement with energy storage company B2U Storage Solutions. Used batteries from thousands of Waymo robotaxis will be transformed into large-scale storage facilities to support the power grids in California and Texas.

Stabilizing the Grid with Used Batteries

B2U Storage Solutions specializes in collecting used batteries removed from EVs and installing them in large-scale stationary energy storage projects. Freeman Hall, CEO of B2U, told Ars Technica, “Our business is about extracting full residual value from EV batteries that are no longer suitable for vehicle use.” These storage systems store surplus renewable energy during periods of low demand and release it during peak demand to stabilize the power grid.

Under the new agreement, B2U will source not only end-of-life batteries from decommissioned Waymo vehicles but also used batteries replaced during vehicle operation. As part of its preventative maintenance strategy, Waymo replaces batteries strategically to improve their performance. Adam Lenz, Waymo’s Head of Sustainability and Environmental Affairs, explained, “These batteries still have a lot of life left in them. That’s why we’re focusing on second-life applications.”

Sufficient Capacity Despite Degradation

Even when EV batteries lose some of their capacity, they can still be effectively used for grid-level energy storage. According to a 2025 analysis by telematics company Geotab (which studied over 22,700 EVs across 21 models), the average annual capacity loss of EV batteries is approximately 2.3%. This means that even after eight years, they can retain more than 81% of their original capacity.

Waymo currently operates a fleet of around 4,000 vehicles, primarily Jaguar I-Pace models with 90kWh lithium-ion batteries. The company has also begun deploying its “Ojai” robotaxi, manufactured by China’s Zeekr, which features a 93kWh battery. Waymo acknowledges that its vehicles cover much longer distances than typical consumer EVs, stating that “they exceed the distances driven by regular consumers.”

B2U’s CEO Hall has assessed the impact of battery degradation, stating, “While there is some capacity loss, the batteries still retain significant capacity when they are repurposed.” Although the average mileage of the batteries at the time of replacement has not been disclosed, it is expected that Waymo’s high utilization rates lead to faster degradation compared to standard EVs.

Supporting California and Texas

As Waymo’s fleet expands, the total capacity of repurposed batteries could reach several hundred megawatt-hours. These energy storage systems will become vital resources for stabilizing the power grids in California and Texas, which face significant fluctuations in renewable energy generation. They are expected to store surplus solar power during the day and release it during peak evening demand.

While the reuse of EV batteries for second-life applications is a challenge for the industry as a whole, direct agreements between large-scale fleet operators like Waymo and energy storage companies are still rare. For regular EVs, it can take years for used batteries to reach the market, but Waymo’s shorter operational cycles mean that used batteries become available at a relatively faster rate.

Notably, Waymo is a subsidiary of Alphabet, which recently raised $85 billion in funding, as reported (see related article). As investments in autonomous driving technology accelerate, the reuse of batteries could contribute to revenue generation and improve the company’s sustainability and environmental, social, and governance (ESG) profile.

Editorial Perspective

Short-Term Impact: This agreement highlights the emergence of a second-life market for EV batteries, involving direct transactions between fleet operators and energy storage providers. Over the next 3–6 months, similar reuse agreements are expected to gain traction among ride-hailing services and logistics companies. With Waymo’s shorter battery replacement cycles compared to regular EVs, B2U can secure a stable supply, making it easier to plan energy storage projects. In California and Texas, where grid storage projects are on the rise, used batteries could offer a cost-competitive alternative to new grid-scale batteries.

Long-Term Outlook: Over the next 1–3 years, as Waymo’s fleet grows from thousands to tens of thousands of vehicles, the total capacity of repurposed batteries could reach a scale sufficient to build multiple grid-scale storage facilities. For power utilities, this provides a new procurement option. Simultaneously, auto manufacturers may need to rethink battery design philosophies, focusing on how to recover residual value. This could lead to advancements in easily replaceable battery packs and standardized monitoring data for battery health.

Editorial Questions: One key question is the criteria Waymo uses to remove batteries from vehicles as part of its “preventative maintenance.” Without disclosed thresholds for mileage or capacity degradation, it’s difficult for third parties to evaluate the real value and condition of these used batteries. Additionally, since the profitability of B2U’s storage projects depends on electricity market prices, how should the long-term stability of their business model be assessed? In Japan, are the conditions right for taxi and logistics companies to adopt similar reuse schemes? This remains an open topic for discussion.

References

• Ars Technica: Used Waymo robotaxi batteries become backup storage for power grids — Published June 4, 2026
• Related internal article: Alphabet Raises $85 Billion Amid Growing Demand for AI Investments