On 10 September 2026, four pieces of second-life battery storage news landed on the same day. In Korea, a five-company consortium led by Hyundai Motor and Kia announced a pilot built around a 200kWh storage system assembled from used electric vehicle packs. The same day, Energy Storage News gathered progress reports from three second-life storage companies abroad into a single article.
Read side by side, the four are not a ranking. Each sits at a different stage, and each is working through a different business structure at that stage.
Korea: 200kWh Coupled with a Fast Charger
Here is what the announcement says. Hyundai Motor, Kia, LG Energy Solution, Hyundai Engineering and Wonik PNE held a launch event on 10 September at Wonik PNE’s Dongtan site in Hwaseong, Gyeonggi Province. Used packs pulled from vehicles on Hyundai Motor Group’s dedicated EV platform, E-GMP, were assembled into a 200kWh UBESS — Used Battery Energy Storage System — coupled to an EV fast charger. The system stores power during low-tariff hours and discharges it into fast charging when tariffs are high. LG Energy Solution builds the unit and supplies the diagnostics and operating technology; Hyundai Engineering assesses commercial viability and how the system meshes with charging infrastructure.
It is worth separating what was announced from what has been confirmed. The source is a press release, and the wide Korean coverage traces back to it. The participants, the site, the capacity, the origin of the packs and the operating concept are the announced details that can be checked against the release. The verification items the consortium listed — charge-discharge control algorithms, system safety and reliability, how well the packs hold performance, charging service quality and operating efficiency — are a plan for what they intend to check, not results they have. KPI News noted that the packs’ procurement route, service life and remaining capacity were not disclosed. In other words, the variable that most determines how second-life storage performs — which batteries, screened against which threshold — is still outside the public record.
The application itself is consistent with the three questions this blog set out in how used batteries get matched to an application: it does not demand the burst power an EV does, it sits fixed at a charging site where cells can be monitored continuously, and it uses packs whole rather than breaking them down.
Abroad: Commercial Operation, Regulatory Standing, Fresh Capital
The three companies Energy Storage News grouped together are each clearing a different gate.
B2U Storage Solutions — in commercial operation. Its 28MWh Bexar Martinez project near San Antonio, Texas has entered commercial operation, connected within utility CPS Energy’s service territory and the second Texas site built around the company’s patented second-life storage cabinets. Third-party financing has closed, and the company says projects using its technology qualify for the domestic content bonus under the US investment tax credit. Cuyama and Sierra in California are cited alongside it as operating sites.
Moment Energy — establishing regulatory standing. The Vancouver-based manufacturer says a third-party review by a major US law firm confirmed it is not a prohibited foreign entity under US tax rules and that it meets the FEOC requirements, with the review covering corporate ownership, effective control and debt financing structure. Its Luna BESS is described as a 400kWh/1MWh system that the company says can scale to 10MWh. It raised a US$40 million Series B in May 2026.
Rebaba — raising capital and scaling production. The Swedish company closed an oversubscribed seed round of SEK44.1 million (US$4.6 million), led by the venture firm Sistafund with participation from the pan-European initiative EIT Urban Mobility. It has a year of production behind it at Stockholm’s CircularHub and commercial deployments running in Sweden, and plans to lift output to 40MWh a year on the back of newly signed contracts in Sweden and Denmark.
Collapsing the three into “the rest of the world is already commercial” erases the distinction. Reaching commercial operation, securing regulatory standing and raising capital are separate gates, and clearing one does not stand in for another.
What Shapes the Business Structure
What follows is interpretation. The striking thing about the B2U announcement is how explicitly policy appears in the financing structure. What the article does not say is how the project earns revenue in the power market. What can be confirmed is narrower: tax-credit eligibility, closed third-party financing and the project’s acquisition are presented alongside the fact of commercial operation.
The Korean pilot was designed around a charging site rather than power sales, which reads as looking for value in charging operations rather than wholesale trading. There is room to read that choice as a function of institutional and market conditions rather than of technical maturity. Routes for second-life storage to earn revenue in Korea’s power market are not yet especially wide, whereas a charger-coupled system can work inside retail time-of-use tariff differences without first having to prove a wholesale revenue path. That is a reading of the structure, though, not a reason the participants gave — and the US tax credit architecture does not transfer to Korea as-is. The most these four cases support is that the same technology, placed on different rules, can surface as a different business.
The Same Week in Seoul
On 14 September, reports said the Seoul Metropolitan Council had passed an amendment to the city’s ordinance on fostering the used EV battery industry. It reframes used batteries as circular resources open to reuse, remanufacturing and recycling rather than as waste, and adds safety management and performance assessment to the support programmes the city may fund. What a municipal ordinance creates, though, is a basis for funding, not a certification requirement. The inspections and installation rules a second-life storage business must actually clear still sit in national law — a layering this blog mapped in KC 62619, KC 10031 and KS C IEC 62933.
What ARC Is Watching
The same gaps recur across all four. How far below new-build the installed cost per kWh of a second-life system actually falls; how many further years of service the packs deliver; how thermal runaway propagates differently once cells with mismatched histories share a system; what design and testing cost it takes to fold pack structures that differ by vehicle model into one product line. Economics, remaining life, fire safety and the cost of standardisation — none of the four appeared as a number in any of these announcements, and all four remain undisclosed or still to be proven. What is visible today is only that each party is converging on a structure that fits the rules and market it operates in. The thing to watch is less that pilots have started than which of those four numbers surfaces first.
Related: How used batteries get matched to an application, KC 62619, KC 10031 and KS C IEC 62933
Source: [Energy Storage News] “Second-life BESS firms B2U, Moment and Rebaba advance project operations, US compliance, and new financing” (10 Sep 2026) (https://www.energy-storage.news/second-life-bess-firms-b2u-moment-and-rebaba-advance-project-operations-us-compliance-and-new-financing/)
Source: [News1] “Hyundai Motor Group launches used EV battery storage pilot with LG Energy Solution and Wonik PNE” (10 Sep 2026, in Korean) (https://www.news1.kr/industry/auto-industry/6286227)
Source: [KPI News] “Why Ioniq and EV6 batteries went to storage before the cars were scrapped” (11 Sep 2026, in Korean) (https://www.kpinews.kr/newsView/1065600219800991)
Source: [Kukje News] “Seoul Metropolitan Council passes EV battery recycling ordinance amendment” (14 Sep 2026, in Korean) (https://www.gukjenews.com/news/articleView.html?idxno=3695074)