B2U Starts 28 MWh Texas Battery Using Repurposed EV Packs

B2U Storage Solutions announced September 9 that its Bexar Martinez battery energy storage system near San Antonio, Texas, has entered commercial operation, with the B2U repurposed EV battery project now delivering 28 MWh of grid services to ERCOT within CPS Energy’s service territory.

The facility is built entirely from repurposed electric-vehicle batteries. B2U says Bexar Martinez is its second operating Texas project using its stationary-storage architecture and brings its ERCOT portfolio to more than 50 MWh.

Bexar Martinez has entered commercial operation

The September 9 B2U announcement distributed through GlobeNewswire confirms that Bexar Martinez has moved from construction into commercial operation.

That represents a substantive change from B2U’s earlier project information, which described the facility as under development after breaking ground in April and receiving equipment in June.

B2U’s project materials previously described Bexar Martinez as a 10 MW/24 MWh system using more than 700 EV batteries. The new commercial-operation announcement describes the facility as delivering 28 MWh of grid services.

The difference indicates that the current operating energy figure is higher than the earlier project description, but B2U’s announcement does not provide enough technical detail to determine whether the increase reflects additional installed battery capacity, final commissioning measurements or another reporting change.

B2U repurposed EV battery systems use packs without conventional recycling first

B2U’s technology is designed to take battery packs retired from electric vehicles and use them in stationary energy-storage systems rather than immediately dismantling the packs for materials recycling.

EV batteries can leave automotive service while retaining useful energy-storage capacity. Stationary applications have different weight, space and power-density requirements than vehicles, creating an opportunity to extend the useful life of qualifying packs before eventual recycling.

The U.S. Department of Energy has separately supported research and demonstration programs examining second-life EV batteries for stationary storage, including applications involving grid resilience, peak management and renewable-energy integration.

Solar Power World independently confirmed Bexar Martinez’s commercial operation and the 28 MWh figure.

Texas now accounts for more than 50 MWh of B2U’s portfolio

B2U’s other operating Texas project is Bexar Corilla near San Antonio. Company materials describe that facility as a roughly 10 MW system that entered operation in 2025 and also uses hundreds of repurposed EV batteries.

With Bexar Martinez operating, B2U says its Texas facilities provide more than 50 MWh of grid services to ERCOT.

Across Texas and California, the company says it manages more than 5,000 repurposed EV batteries and operates roughly 100 MWh of stationary storage in standalone and solar-paired configurations.

The San Antonio region is also seeing conventional utility storage development. Microgrid Media previously reported that CPS Energy is evaluating up to 20 MW of distribution-scale battery storage and an islandable microgrid under a separate utility procurement.

Bexar Martinez should not be confused with those proposed CPS Energy-owned systems. B2U’s facility participates in ERCOT and is merely located within the municipal utility’s service territory.

Second-life storage faces a different engineering problem

A conventional new-build BESS can be assembled from battery cells and modules manufactured to common specifications at approximately the same time.

Repurposed EV packs can arrive with different operating histories, remaining capacities and degradation characteristics. A second-life storage platform therefore needs battery-management and control systems capable of monitoring and operating packs whose condition is not necessarily identical.

B2U says its EV Pack Storage architecture allows EV batteries to be integrated without dismantling and rebuilding the original packs.

The approach is materially different from the new utility-scale batteries used at projects such as Ørsted’s 250 MW/500 MWh Old 300 Storage facility in ERCOT, which uses purpose-built Tesla Megapacks.

Commercial operation will provide a larger real-world test

The significance of Bexar Martinez is therefore not its absolute size. At 28 MWh, it is far smaller than the hundreds of megawatt-hours being deployed at some conventional Texas battery projects.

Its importance is the use of retired vehicle batteries in a commercial grid-connected facility participating in one of the country’s most active energy-storage markets.

B2U says its projects have obtained third-party financing and qualify for the domestic-content bonus under the federal investment tax credit. The company also says Bexar Martinez and its other projects have been acquired by B2U Infrastructure Partners.

Those are company disclosures rather than independent measures of project economics. The longer-term test will be operating availability, degradation, maintenance requirements and revenue performance as the repurposed packs accumulate additional stationary-storage cycles.

B2U expects to deploy more than another 50 MWh in ERCOT over the next six months. That remains a forward-looking target; Bexar Martinez’s 28 MWh commercial-operation milestone is the capacity now confirmed as entering service.