Japan tightens grid access as battery queue reaches 172 GW

Japan now requires generators, including battery developers, to prove rights to their sites to keep a grid connection, as regulators move to curb capacity hoarding in a battery queue that far outruns the less than 1 GW of grid-scale storage actually connected.

Japan’s Organization for Cross-regional Coordination of Transmission Operators (OCCTO) now requires generators to prove rights to their project sites to keep grid connection reservations. It is the third measure this year intended to stop low-certainty projects from holding grid capacity in a queue dominated by battery storage.

From Oct. 1, projects in Japan that receive grid connection approval must submit documents proving their right to use the project site within two months, or lose their grid connection reservation, under updated guidance published by OCCTO.

The rule applies to contract applications received from Oct. 1 and covers all generation projects except those under Japan’s feed-in tariff and feed-in premium schemes. Upgrades at existing sites are exempt where they do not increase output or otherwise affect the grid, and transmission operators can extend the two-month deadline where there are reasonable grounds.

The requirement was developed by the Next-Generation Grid Working Group of Japan’s Ministry of Economy, Trade and Industry (METI), which said it is meant to stop projects with low business certainty from holding onto connection reservations, so that more viable projects can connect quickly.

Grid-scale batteries dominate the queue. At the end of December 2025, about 172 GW of grid-scale battery capacity was at the connection-study stage and about 30 GW at the contract-application stage, against about 0.64 GW actually connected, according to ministry figures. At the end of September 2024, the equivalent figures were about 88 GW and 6.2 GW.

Two earlier measures target batteries directly. From Aug. 1, each transmission operator caps the number of grid-scale battery connection studies a single company can request in its area, after the ministry’s working group found several companies had filed more than 100 requests with one operator in a short period. Requests above the cap are returned without review. The caps range from five in Hokkaido, Hokuriku, Chugoku, and Shikoku to 12 in Kansai, with 11 in the Tokyo area. They also apply to batteries co-located with other generation where the battery is the main equipment.

Since June, grid-scale battery projects must also file their generation-side and demand-side contract applications at the same time. OCCTO said filing them separately allowed other applications to land in between, changing the assumptions behind a project’s grid study and with them its connection works, costs, and timeline, and delaying approvals.

Japan also supports grid-scale storage through its Long-Term Decarbonization Power Source Auction, which awarded 1.25 GW of battery storage across 19 projects in its third round in May, down from 1.37 GW the previous year. Projects under construction include a 67 MW/230 MWh battery in Fukuoka prefecture backed by Itochu, Mitsubishi Estate, and Tokyo Century.

The post appeared first on pv magazine Global.