Unaccepted Even if Applied? Grid-Scale Battery Connection Studies Heading Toward 'Application Limits' by August

BESS NEWS, a specialized news site that provides vital information on grid-scale batteries free of charge, has recently published an explanatory article titled "Unaccepted Even if Applied? Grid-Scale Battery Connection Studies Heading Toward 'Application Limits' by August - 'Unanswered Applications' and 'Land Rights Documents' that BESS Operators Must Check." This article synthesizes practical access issues for BESS operators based on the results of the public consultation on the proposed changes to the "Articles of Incorporation, Operational Rules, and Guidelines for Power Transmission and Distribution Services" announced by the Organization for Cross-regional Coordination of Transmission Operators, Japan (OCCTO) on May 12, 2026, as well as materials from the 10th "Next-Generation Power Grid Working Group" of the Ministry of Economy, Trade and Industry (METI) and the Agency for Natural Resources and Energy.

What is particularly crucial in these documents is the impending direction to establish a cap on the number of connection study applications per identical grid connection applicant for grid-scale batteries. Furthermore, in the contract application process, the importance of documents proving the legal right to use the project land is elevated, warning that failure to submit these documents after connection approval could pose a risk of connection reservation cancellation.

BESS NEWS frames these proposed changes not merely as regulatory revisions, but as critical practical themes affecting grid-scale battery business development, site selection, connection studies, investment decisions, and project management. Specifically, it provides easy-to-understand explanations on the difference between "applied" and "accepted," the point that even applications submitted before August 1, 2026, can be subject to the limit if they remain unaccepted by that date, and the fact that the regional limit numbers are merely reference estimates rather than official figures.

Table of Contents

Themes Explained by BESS NEWS This Time
1-1. Results of public consultation on the proposed rule changes published by OCCTO
1-2. Main changes BESS operators should watch
1-3. The importance of distinguishing between "decided," "scheduled for implementation," and "reference estimates"

Practical Points BESS Operators Should Note
2-1. Introduction of limits on connection studies for grid-scale batteries
2-2. Even applications before August 1, 2026, can be subject to limits if unaccepted
2-3. Documents proving land rights become more critical

Precautions Regarding Common Practical Misunderstandings
3-1. Regional limits are reference estimates as of March 2026, not official figures
3-2. It cannot be categorically stated that "exceeding 2 months means guaranteed immediate cancellation"
3-3. Developing across multiple candidate sites requires strict project screening and acceptance management

1. Themes Explained by BESS NEWS This Time

In this BESS NEWS article, practical changes regarding grid access for grid-scale batteries are summarized based on the public consultation results on OCCTO's proposed rule changes and METI's working group materials. According to OCCTO's publication page, the public consultation was conducted from April 8 to April 28, 2026. No comments were received regarding the changes to the Articles of Incorporation and Operational Rules. Meanwhile, comments were submitted for the changes to the Guidelines for Power Transmission and Distribution Services, and the response table outlines six comments alongside OCCTO's replies. There are two major changes BESS operators must verify.

First, there is a move to cap the number of connection study applications for grid-scale batteries. A connection study is a procedure to determine whether a battery can be connected to the power grid, confirming necessary construction, timelines, and estimated costs.
Second, documents proving the right to use the project land will become essential during the contract application process. 'Usage rights' refer to the legal right to use the land, such as ownership or leasehold rights.

This system change indicates a stronger shift towards evaluating "whether the project is truly viable for commercialization" and "whether the business can actually be conducted on that land" in BESS development. On the other hand, when reporting, it is vital not to conflate decided facts, proposed changes, implementation schedules, and reference estimates. The implementation date is generally set for August 1, 2026, or the date of approval by the Minister of Economy, Trade and Industry, whichever is later. Therefore, it is structured as "scheduled to be implemented around August 1, 2026" rather than definitively stating "will start on August 1, 2026."

2. Practical Points BESS Operators Should Note

The proposed changes introduce Article 71-2 to the Operational Rules and Article 81-2 to the Guidelines for Power Transmission and Distribution Services, setting a limit on connection study applications for grid-scale batteries. The targeted batteries are energy storage facilities connected to the transmission grid. Batteries co-located with power generation or demand facilities are also included if deemed applicable by the transmission operator based on capacity. Under the proposed Article 81-2, if the number of pending connection studies from the same applicant exceeds the limit published by the operator, the operator will not verify the application documents, accept the connection study application, or notify the study fee amount for the excess applications. The crucial distinction here is between "applied" and "accepted." "Applied" means the operator has submitted the documents. "Accepted" means the transmission operator has verified the documents and proceeded to accept the connection study. METI materials stipulate that cases already accepted beyond the limit by July 31, 2026, will receive connection study responses as usual.

Conversely, even if applied before August 1, 2026, the limits apply to cases not accepted by August 1, 2026. Therefore, the practical dividing line is not "whether applied before August 1, 2026," but "whether accepted by August 1, 2026." The logic behind the limit is based on the number of accepted connection studies per operator over a 3-month period in past fiscal years before the surge, using either "average + 2σ" or "minimum 5 cases," whichever is higher. However, the actual limits will be set and published by each transmission operator. METI materials provide reference estimates as of March 2026: Hokkaido 5, Tohoku 6, Tokyo 11, Chubu 5, Hokuriku 8, Kansai 10, Chugoku 5, Shikoku 5, Kyushu 8, and Okinawa "—". Nevertheless, these are not official figures. As actual limits may differ, BESS operators must check official announcements from each operator.

The other critical change concerns land rights documents. OCCTO materials explain that submitting documents proving usage rights for the project land will be an added requirement in the contract application process. Since FIT/FIP power sources already require these documents institutionally, this revision targets non-FIT/FIP generation facilities, including grid-scale batteries. The proposed Article 97 of the Guidelines states that if an applicant fails to submit the land rights documents for the facility site within two months after connection approval, the operator can cancel the connection reservation. However, if submission within two months is recognized as reasonably difficult, a separate period determined by the operator applies. Therefore, strictly speaking, it is not a case of 'immediate cancellation upon exceeding two months'