Korea’s supply of retired EV batteries is growing fast. According to the Ministry of Climate, Energy and Environment, domestic volume reached 8,321 units in 2025 and is projected to hit 107,500 by 2030. That 2030 figure is still just a projection, though, and past forecasts have missed actual volume by a wide margin — a gap this piece revisits later as a supply-side variable. Ask where all of that can go, and the answer so far converges on one thing: energy storage systems (ESS). Anyone evaluating a second-life battery business wants to know why so few other uses have shown up, and whether that’s likely to change. Rather than listing applications, this piece starts from what actually changes inside a battery once it comes out of a car, and works forward from there.

What actually changes

A battery pulled from an EV is not the same battery it was when new. Korea’s pre-removal performance grading system — targeted for enforcement in 2027 — evaluates that difference along three axes: performance (remaining capacity), safety (cell voltage deviation), and history (maintenance, inspection, and recall records). Carried over as characteristics of a retired battery, these read as follows.

First, remaining capacity has dropped. The battery was removed precisely because it no longer meets the range and output an EV requires. Second, cell-to-cell variance has widened. Small resistance mismatches present from manufacturing grow larger as charge-discharge cycles accumulate over years of use. Third, history is uneven. Driving patterns, service records, and accident or recall history differ from car to car, so batteries from the same model end up in different states. None of these three forms of degradation makes the battery unusable, though — a meaningful amount of energy-storage capacity remains, and that remainder is the whole basis for reuse.

From characteristics to a judgment rule

Translating those three characteristics into a rule for choosing an application leaves three questions.

  • Does the application demand EV-level instantaneous power and energy density, or is gradual charge-discharge enough?
  • Is it a fixed environment where battery condition can be monitored continuously and cell variance managed, or one where the battery is carried or moved by a person?
  • Can a retired battery pack be reconfigured at the module level, or does it need to be torn down further for size and weight reasons?

The more favorably an application answers all three — low power, fixed setting, module-level reuse — the more safely a retired battery fits it. By this rule, ESS is one of the applications that answers all three favorably, not the only possible one.

Why ESS got there first

An ESS cycles charge and discharge from a stationary position. It never needs the instantaneous high power an EV draws under hard acceleration or braking. Because it’s installed in access-controlled sites like power plants or industrial complexes, a battery management system can monitor and manage cell variance continuously. This lines up with the government’s classification standard, which separates remanufacturing from reuse as distinct application grades based on the pre-removal performance evaluation: reuse is defined as “reassembled for other purposes such as energy storage systems,” as distinct from remanufacturing, which involves replacing and repairing components to put a battery back into an EV. Reuse keeps the pack or module largely intact and simply repurposes it — a fit for how ESS reuse actually works.

Policy support built up around ESS earlier, too. A demonstration project led by Hyundai Motor Group with Korea Hydro & Nuclear Power and OCI, approved under an industry ministry regulatory sandbox in 2021, paired a 2MWh-class reused-battery ESS with a solar plant at Hyundai’s Ulsan factory, with an announced plan to scale that into a 3GWh-class reused ESS rollout. Where the judgment rule already favors ESS, policy support reinforced it — which is a large part of why ESS scaled first.

Why other uses are still small

The same rule explains why other applications are lagging rather than absent. After Korea revised its Electrical Appliances and Consumer Products Safety Control Act in March 2023, a safety inspection regime for reused cells took effect that October, and pilot cases beyond ESS started appearing — camping power banks (Goodbye Car), agricultural aerial work platforms (Daeryun Engineering), and smart solar streetlights (Solueum). These applications generally satisfy the first question, low power, but fare worse on the second and third. A power bank is carried by a person, which rules out continuous monitoring. Aerial platforms and streetlights sit outdoors and move or vibrate, exposing cells to harsher temperature and vibration conditions than an ESS installation. Some of these products need the pack broken down further for compactness, which works against keeping modules intact. The safety certification regime is also still young. For now these remain individual pilot projects that haven’t reached ESS’s economies of scale.

Passing the judgment rule is one thing; securing a steady supply of batteries is another variable that determines scale. When Korea’s Ministry of Environment announced the 2023 revision to the safety act, it projected annual retired-battery volume would reach 31,700 units by 2025. The actual 2025 figure, tallied by the Ministry of Climate, Energy and Environment, came in at 8,321 — well under a third of that projection. A company that designs a business around power banks, aerial platforms, or streetlights can still struggle to commit to mass production if the volume that application needs builds up slower than forecast. ESS projects tend to absorb larger volumes per deployment and can pool variance in cell condition across many packs, which appears to have made it easier to sustain an ESS business through a period where overall supply grew more slowly than expected than it has been for other applications.

ARC’s take

ESS’s dominance doesn’t look like the market missing other possibilities — it looks like retired-battery characteristics happening to fit stationary, low-power, module-reusable applications first. That power banks, aerial platforms, and streetlights already have pilot cases on the books is itself evidence that ESS isn’t the only application the judgment rule allows. What’s still unresolved is whether safety certification and monitoring infrastructure can mature enough for mobile, compact settings to close the gap with ESS.

Source: [Kim & Chang] “Announcement of the Legal, Regulatory, and Infrastructure Plan to Foster the Retired Battery Industry” (https://www.kimchang.com/ko/insights/detail.kc?sch_section=4&idx=30348)

Source: [Korea.kr Policy Briefing] “Growing the ‘Retired Battery’ Industry — Government to Push Fostering Legislation This Year” (https://www.korea.kr/news/policyNewsView.do?newsId=148931288)

Source: [IndustryNews] “Retired Battery Reuse Regulations Take Shape — Revised Safety Act Takes Full Effect in October” (https://www.industrynews.co.kr/news/articleView.html?idxno=49332)

Source: [e-Policy] “Reusing EV Batteries: What Is R-ESS?” (https://e-policy.or.kr/web/lay1/bbs/S1T10C49/B/13/view.do?article_seq=692)

Source: [Hankook Ilbo] “Solar Power Linked to Retired-Battery ESS — Hyundai Motor Launches Demonstration Project” (https://www.hankookilbo.com/News/Read/A2021011013100000113)

Source: [eToday] “Korea’s ‘Urban Mine’ Opens Up — Retired Battery Market Gears Up [Climate Ministry’s First Org Chart]” (https://www.etoday.co.kr/news/view/2608344)

Source: [Law Times] “Key Provisions and Implications of the Retired Battery Act” (https://www.lawtimes.co.kr/news/articleView.html?idxno=222505)