Japan Rewrites Its Battery Strategy: What the June 2026 "Battery and Power Source Industry Strategy" Means for Grid-Scale BESS Owners and Investors

• On June 2, 2026, Japan's Ministry of Economy, Trade and Industry (METI) revised its 2022 Battery Industry Strategy for the first time in roughly four years, renaming it the Battery and Power Source Industry Strategy (蓄電池・電源産業戦略). The revised strategy treats batteries not as standalone cells but as the core of "power source systems" — and that wider scope now anchors Japan's industrial policy for the sector.
• For asset owners, the operative change is this: the strategy states that installation subsidies and the Long-Term Decarbonized Capacity Auction (LTDA) should require third-party conformity certification against battery safety standards and guidelines. Operators are also expected to submit accident cases and countermeasures, and to implement cybersecurity and supply-chain disruption risk measures.
• The backdrop is a surge in grid-scale battery development: grid-connection (contract) applications reached roughly 24 GW nationwide (excluding Okinawa) as of end-September 2025 — about 3.9x year on year, per Japan's Agency for Natural Resources and Energy (ANRE).
• The strategy itself has been formally revised and published, but it is a direction-setting policy document: its requirements still have to be written into binding rules for individual programs. Parts are already live, however — the third LTDA round (bids in January 2026) already required evidence of JC-STAR ★1 security certification for battery control systems, and grid-code revisions are set to extend the same requirement to new grid connections from April 2027, including pure merchant assets.
• The practical move for owners and investors is to build safety certification and security compliance into procurement specifications now, rather than retrofitting after each program's final rules are published.

At the eighth meeting of its Battery Industry Strategy Council on June 2, 2026, METI presented a full revision of the Battery Industry Strategy originally formulated in August 2022 — the first revision in roughly four years — under a new name: the Battery and Power Source Industry Strategy.

First, a note on what this document is. The strategy itself has been formally revised and published — METI's press release announces the revision as completed. What it is not is a finalized amendment to subsidy guidelines or auction rules: it is a national industrial strategy, a direction-setting policy document, and the binding details still have to be written into each program's own documents. The accurate reading is that the strategic direction is now fixed, while its translation into binding program rules is still to come.

The headline change is the addition of "power source" (電源) to the strategy's name. The revision reframes the strategy's object from battery cells to power source systems built around batteries, with competitiveness assessed not only on energy density (capacity) but also on power density (output) and other dimensions. METI cites a global oversupply structure in battery markets, the materialization of supply-chain risks, and growing demand for sophisticated power control — from AI data centers to medical and disaster-resilience applications — as the background.

One nuance matters for readers following Japan from abroad: this is not the moment Japan first recognized batteries as power sources. Grid-scale batteries were already eligible to bid in the LTDA as decarbonized power sources, and grid-scale battery storage above a certain size threshold is already treated as a power generation business under Japan's Electricity Business Act. What changed is the scope and emphasis of the national industrial strategy — batteries-as-systems are now at its center.

The manufacturing-side targets were also reset: the goal of establishing 150 GWh/year of domestic production capacity was pushed back from "by 2030" to "2030 to the mid-2030s," battery-related revenue at Japanese companies that manufacture battery cells is targeted to triple from 2025 levels by 2035 (a scale of roughly JPY 5 trillion, according to press reports), and all-solid-state batteries are targeted for full-scale commercialization around 2030.

This article, however, is not about the manufacturing side. What lands directly on the desk of anyone who owns or is building a MW-scale battery in Japan is the set of deployment- and operations-side requirements written into the strategy. We take those up next.

The revision did not happen in a vacuum. According to materials presented to ANRE's Next-Generation Power Grid Working Group on February 9, 2026, grid-connection (contract) applications for grid-scale batteries reached approximately 24 GW nationwide (excluding the Okinawa area) as of the end of September 2025 — roughly 3.9x the level a year earlier.

Against flat solar and declining wind applications, battery storage is the outlier (source: ANRE Next-Generation Power Grid Working Group, February 9, 2026, Document 1-1; nationwide figures exclude the Okinawa area).

Two caveats are essential. First, this is an application-based figure, not operating capacity. Second, the same ANRE document notes that many applications have no realistic path to construction — speculative queue positions that lock up grid capacity. Regulators are responding: at the same working group in April 2026, ANRE proposed capping the number of unanswered (pending) connection-study applications a single developer can hold at 5 to 11 per region, with operation starting in August 2026.

In other words, the Japanese market has entered a selection phase. Applications are piling up, but the projects that actually reach construction and commercial operation will be filtered — and the safety, cybersecurity, and supply-chain requirements discussed below are best read as part of that filtering logic.

Of everything in the strategy, four items bear directly on owners and developers of grid-scale battery assets. All four are stated as policy direction, but as the right-hand column shows, some have already crossed into binding practice through individual programs.

Two points deserve emphasis.

First, the third-party certification requirement is aimed at both subsidies and the LTDA (the strategy's wording extends to similar programs via "etc."). And the certification infrastructure already exists: NITE's guideline and the accredited certification and testing bodies that go with it mean this is not a requirement waiting for institutions to be built.

Second, cybersecurity has already moved past the "direction" stage. JC-STAR ★1 evidence was a real bid requirement in the most recent LTDA round, and under the planned grid-code revision, any battery or solar project connecting from April 2027 onward will need compliant control equipment — regardless of whether it ever touches a subsidy or auction. Merchant assets are not exempt.

A standing caveat: the strategy's language will be translated into binding requirements through each program's own documents — subsidy solicitation guidelines, LTDA bidding rules, and so on. Always confirm the final form in the primary documents for the specific program you are targeting.

The impact differs by revenue strategy, so it helps to separate the two tracks most foreign IPPs and funds in Japan are pursuing: the contracted-revenue track (subsidies and the LTDA) and the merchant track (JEPX trading plus the balancing market).

For the LTDA track, this is a change to the competitive conditions of an intensely contested auction. Per OCCTO's published results, Round 1 (results announced April 2024) saw 4,559 MW of battery bids against 1,092 MW awarded — a success rate of roughly 24%. Round 2 (April 2025) awarded 27 battery projects totaling about 1,370 MW. From Round 3 (results announced May 13, 2026), batteries were split into separate lithium-ion and non-lithium-ion categories; awarded lithium-ion capacity totaled roughly 551 MW, with batteries overall at roughly 1,251 MW. In a market this competitive, a single missing certificate or misread requirement can cost an entire bid round — and third-party certification involves testing and review lead times that cannot be compressed at the last minute.

For the merchant track, the temptation is to file this under "not my problem." Two mechanisms argue otherwise. The grid code will apply security requirements at the point of connection from April 2027, regardless of market strategy — meaning the requirement lands at equipment selection, not at market entry. And once third-party safety certification becomes the standard for subsidized and auction-backed assets, lenders and insurers can be expected to reference the same benchmarks; uncertified assets would then face friction on financing and insurance terms even without any formal mandate.

There is one further implication specific to foreign owners. Every primary document in this story — the METI strategy, ANRE working group materials, OCCTO bidding rules, NITE's safety guideline, the IPA's JC-STAR scheme, the grid-code revisions — is published in Japanese, by a different institution, on a different revision cycle, with requirements that move between draft and final. Tracking this landscape from an overseas head office, in translation and with a lag, is exactly how bid requirements get missed. Whatever the operating model, owners need a mechanism — in-house Japanese-speaking regulatory capability or a local partner with skin in the game — that reads these documents as they are published, not after they bind.

Waiting for each program's final rules before acting means absorbing the lead time for certification and possible equipment changes on the back end. Building the requirements in at the procurement and design stage costs far less. Concretely:

Write certification into procurement specifications. For cells, modules, and the integrated system, ask suppliers at the quotation stage about third-party certification status, plans, and cost allocation under NITE's safety guideline, and fix the answers in the procurement specification. For control systems (BMS, PCS, EMS), confirm JC-STAR ★1 compliance or the compliance timeline. For projects with grid connection planned in FY2027 or later, both should be preconditions, not preferences.

Inventory the paper trail on existing and under-construction assets. Type test reports, certificates, factory inspection records — take stock of what you hold against what third-party conformity evidence would require, and confirm with OEMs what can be issued and how long it takes.

Put incident response into the O&M contract. The strategy points toward mandatory submission of accident cases and countermeasures. Define recording and reporting obligations, with formats, in the O&M agreement, and keep operating and incident logs in a submittable form from day one.

Secure the supply chain contractually. Supply guarantee periods for major components, spare-parts inventory policy, and alternative sourcing routes if an OEM exits the market — these address the strategy's supply-disruption expectations and, equally, the realities of a 20-year asset life.

Make grid applications credible. With per-developer application caps arriving in August 2026, applications backed by site control, financing, equipment, and an operating plan will move faster than speculative ones.

Centralize the evidence. Subsidy applications and auction bids are ultimately document exercises. Keep certificates, test reports, security evidence, and insurance documents in one repository, ready to file the moment a solicitation schedule is published.

LehmanSoft Japan owns and operates a 2.0 MW / 8.1 MWh grid-scale battery station in Chichibu, Saitama Prefecture, which has been in commercial operation on JEPX under AI-driven VPP control since November 2025 and entered Japan's balancing market in March 2026. A second 2.0 MW / 8.1 MWh project in Yame District (Yame-gun), Fukuoka Prefecture is scheduled for grid connection in September 2026.

Operating our own asset has taught us that safety, security, and documentation requirements look like paperwork but are really a test of equipment configuration and operational discipline. Every market entry involves screening, testing, and evidence submission — equipment specifications and test records, control-system architecture, operating procedures. Assembling all of that retroactively, after commissioning, costs multiples of what it costs to build it in at procurement.

The strategy itself is still a direction-setting document. But the receiving infrastructure — NITE's guideline and certification bodies, the JC-STAR scheme already embedded in LTDA bidding — is in place, and we see little chance of this direction reversing. The more likely dynamic is that assets which satisfy the requirements early gain options: subsidies, auction participation, and better financing terms. Of the roughly 24 GW in the connection queue, the projects that reach commercial operation will be selected not just on whether they can be built, but on whether they can be operated — safety, security, and reporting included.

For owners who would rather not build that capability in-house, this is the service we provide. As an aggregator that runs its own stations, LehmanSoft Japan handles market operations across JEPX and the balancing market, together with the market-entry screening and documentation work, end to end — including tracking the Japanese-language primary documents discussed in this article as they evolve. Our fee model is fully success-based, with no fixed or upfront costs, and reporting is available in English. Details and inquiries are on our operation service page; for how we approach multi-market operation under Japan's 2026 balancing-market changes, see this companion article.

1. METI, "Revision of the Battery Industry Strategy into the Battery and Power Source Industry Strategy" (press release, June 2, 2026, in Japanese) https://www.meti.go.jp/press/2026/06/20260602001/20260602001.html
2. METI, Battery and Power Source Industry Strategy (full text, June 2, 2026, in Japanese) https://www.meti.go.jp/press/2026/06/20260602001/20260602001-1r.pdf
3. METI, 8th Battery Industry Strategy Council (June 2, 2026, in Japanese) https://www.meti.go.jp/policy/mono_info_service/joho/conference/battery_strategy2/0008.html
4. ANRE, Next-Generation Power Grid Working Group (February 9, 2026), Document 1-1 on accelerating grid connection of grid-scale batteries and other facilities (in Japanese) https://www.meti.go.jp/shingikai/enecho/denryoku_gas/saisei_kano/smart_power_grid_wg/pdf/007_01_01.pdf
5. OCCTO, briefing materials "Details of the Long-Term Decarbonized Capacity Auction (bidding year: FY2025)" (September 2025, in Japanese) https://www.occto.or.jp/assets/market-board/market/files/202509_youryou_syousaisetsumei_long.pdf
6. OCCTO, "Publication of the Long-Term Decarbonized Capacity Auction award results (bidding year: FY2023)" (announced April 26, 2024; commonly called Round 1; in Japanese) https://www.occto.or.jp/news/market-board_market_oshirase_2024_20240426_youryouyakujokekka_kouhyou.html
7. OCCTO, "Publication of the Long-Term Decarbonized Capacity Auction award results (bidding year: FY2024)" (announced April 28, 2025; commonly called Round 2; in Japanese) https://www.occto.or.jp/news/market-board_market_oshirase_2025_20250428_youryouyakujokekka_kouhyou.html
8. OCCTO, "Publication of the Long-Term Decarbonized Capacity Auction award results (bidding year: FY2025)" (announced May 13, 2026; commonly called Round 3; in Japanese) https://www.occto.or.jp/news/012080.html
9. NITE, Safety Guideline for Battery Storage Systems in Public Procurement and Critical Infrastructure (Version 1, May 14, 2026, in Japanese) https://www.nite.go.jp/gcet/nlab/infra-guideline.html

This article was prepared on June 10, 2026, based on publicly available information. The Battery and Power Source Industry Strategy has been formally revised and published as a direction-setting policy document; the requirements discussed above will take final, binding form through revisions to individual program documents such as subsidy solicitation guidelines and LTDA bidding rules. Always confirm the latest primary documents before bidding or applying.