Japan Solar Update: No.194 (Mar 30 ~ Apr 3, 2026)
The Agency for Natural Resources and Energy (ANRE) of the Ministry of Economy, Trade and Industry (METI) presented a policy to strengthen measures against speculative grid reservations (“empty capacity holding”) for grid-scale battery storage projects.
Under the new policy, projects applying for grid connection contracts from April 2026 onward will be subject to higher security deposits and stricter installment payment rules. This measure follows cases where projects failed to proceed because the required grid construction cost contributions exceeded initial expectations. In addition, when operators apply for grid connection studies, utilities will present information such as the availability of upstream grid reinforcement capacity and the upper limit of construction cost contributions. If the project conditions do not meet these requirements, a mechanism will allow utilities to provide an early response during the study process, preventing unnecessary reservations of grid capacity.
A similar operational framework will also be introduced from April 2026 for high-voltage facilities connecting to distribution networks.
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- The Ministry of Economy, Trade and Industry (METI) proposed operational changes that will lead to accelerate connection assessment
- When applying for connection assessment, applicants present the following: 1) whether it is acceptable to enhance the upper grid, and 2) the maximum amount of the construction cost contribution. Then, the general power transmission and distribution operators will promptly responds after it is found that the conditions are not satisfied
- Measures to prevent the capacity hoarding of grid-scale storage batteries, including an increase in the deposit at the time of contract application, will begin to be applied from projects whose contract applications are received after April 2026
- Review of connection rules for grid-scale storage batteries and Grid Code will also be considered
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Response to rapid grid connection of power generation and other facilities including grid-scale storage batteries
Operational changes that contribute to accelerating connection assessment
When the business operator applies for connection assessment, their conditions (needs) are presented:
- Acceptance of upper grid enhancement
- Maximum amount of the construction cost contribution
During the consideration process by the general transmission and distribution operators, it is possible to promptly respond *when it is found that the needs of the applicants will not be satisfied
*Since the content of response does not match the needs of applicants, the answer will be “interconnection is not accepted” and the applicants cannot proceed to the next step after contract applications.
- This will begin to be applied to high-voltage power generation and other facilities connected to the power distribution grid in April 2026
- The new form of the application form will be published on the websites of the Organization for Cross-regional Coordination of Transmission Operators, JAPAN (OCCTO) and general transmission and distribution companies
Start of measures against capacity hoarding of grid-scale storage batteries
Further response to capacity hoarding at the time of contract application
- Increase in the amount of the deposit at the time of contract application
- Stricter operation of the installment payment system for the construction cost contributions
Measures will begin to be applied to projects whose contract applications are received after April 2026
Review of connection rules for grid-scale storage batteries
- As for non-firm connection on the forward power flow side, it is planned to discuss, aiming to introduce control of planned value with reference to the mechanism on the power generation side
- 189 contract applications totaling 913 MW (as of the end of January 2026) were made, to which the additional measures for early interconnection that began in April 2025 are applied. Measures to flexibly set charging time limits are considered, etc.
About Grid Code
Report on the status of considerations and cybersecurity measures
- Presently, it has been decided to make voltage fluctuation countermeasures for high and low voltage storage batteries a requirement, and reviewing the requirements for Fault Ride-Through (FRT) is being considered
- As a cybersecurity measure, it is planned to revise the technical requirements for grid connection for low-voltage power supplies (PV systems and storage batteries) in October 2027, which will be made known with the cooperation of related organizations
Figure 1 Summary of deliberations on measures for rapid grid connection of power generation and other facilities including gridscale storage batteries
Source: Materials of the 7th meeting of the Working Group on the Next-Generation Electric Grid (February 9, 2026), compiled by RTS Corporation