High Voltage by April 2027, Low Voltage Under 50kW by October! JC-STAR Requirement to Prevent Unconnectable Projects.
BESS NEWS has published an article detailing the upcoming JC-STAR requirements for new grid connections of solar power and storage batteries. Starting April 2027 for high voltage and October 2027 for low voltage under 50kW, control systems with JC-STAR★1 certification will be mandatory, impacting project feasibility and requiring early compliance.
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- 📰 Published: April 14, 2026 at 20:00
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BESS NEWS, a specialized news site that freely publishes important information on grid-connected storage batteries, has recently released an explanatory article that organizes practical issues often overlooked in new grid connections for solar power generation and storage batteries, titled 'High Voltage by April 2027, Low Voltage Under 50kW by October 2027. ~What You Need to Know Before 'Unconnectable Projects' Emerge Due to JC-STAR Requirements~'. According to Ministry of Economy, Trade and Industry (METI) materials, for new solar power generation and storage batteries connected to the grid after April 2027, the use of control systems with communication functions that have acquired JC-STAR★1 will be mandated. For low-voltage (under 50kW) systems only, a transitional measure considering existing stock will begin in October 2027.
What BESS NEWS focused on this time is not merely an 'announcement of system changes.' The critical practical point is that even for low-voltage systems under 50kW, projects applying for grid connection contracts after the revision will fundamentally be unable to connect generation equipment that does not meet the requirements. Furthermore, the same document anticipates projects with lead times between equipment installation and application, stating that it is desirable to use products compliant with the latest grid connection requirements early. In other words, the crucial date to consider is not just the 'construction completion date' but also the contract application date.
The background to this is the real cyber risks extending to distributed power sources. OCCTO's (Organization for Cross-regional Coordination of Transmission Operators) materials introduce a case where approximately 800 remote monitoring devices for solar power generation facilities were cyber-attacked in May 2024 and exploited for fraudulent online banking transfers. Additionally, these requirements are organized within the grid connection technical requirements stipulated by each general transmission and distribution utility based on OCCTO's 'Transmission and Distribution Business Guidelines.' BESS NEWS has taken this point not as a 'recommendation' but as an issue that must be read as an entry condition for connection practices, and has published an article about it.
The article delves into issues such as the following:
How does the 'transitional measure' for low-voltage systems under 50kW apply to which projects?
Is it sufficient to only look at the PCS (Power Conditioning System)?
How far should one check, including EMS (Energy Management System), BMS (Battery Management System), gateways, and remote monitoring devices?
How much practical significance does a manufacturer's 'planned support' have?
According to official documents, the scope of the requirements is **'control systems with communication functions,'** with PCS, EMS, etc., cited as examples. Furthermore, even IP communication devices that appear to be outside the scope are subject to these requirements if they have functions to control power generation equipment or are directly connected to main equipment. BESS NEWS organizes such difficult-to-read primary information into a format that is easy for on-site personnel to understand.
Regarding JC-STAR itself, BESS NEWS does not stop at merely introducing the system name. According to IPA (Information-technology Promotion Agency, Japan), JC-STAR is a security requirement conformity assessment and labeling system for IoT products, with ★1 and ★2 being self-declaration methods. On the other hand, IPA advises against expressions that suggest acquisition is possible before the conformity label is issued, such as 'JC-STAR conformity planned,' and explicitly states that applications may be rejected depending on the results of the verification process. That is why the article explains that inquiries to manufacturers should not end with 'it's planned,' but must ascertain which equipment will acquire it, whether it has already been acquired, when it is expected to be acquired, and where to confirm this information. IPA also publishes a list of products that have acquired the conformity label.
The aim of BESS NEWS with this article was not to assert a definitive conclusion about the system in a single sentence, but to proactively increase the resolution of confusion that actually occurs on-site.
Is it acceptable to view it as 'still far off because it's 2027'?
Is it acceptable to think 'there's a little more leeway for low-voltage systems under 50kW'?
Is it sufficient to estimate it as 'a complete set of battery storage systems'?
What impact will such discrepancies in judgment have on connection practices and processes later on?
The BESS NEWS article is structured to trace these answers based on primary information.
[This article is recommended for the following people]
It is recommended for developers, EPC and construction companies involved in new grid connection projects for solar power generation and grid-connected storage batteries, manufacturers and distributors handling PCS, EMS, BMS, gateways, remote monitoring devices, etc., and financial/investment professionals who want to understand how system changes will affect investment decisions and due diligence. In particular, practical personnel who feel 'it's still a distant matter because it's a low-voltage system under 50kW' should definitely review this content.
[About BESS NEWS]
BESS NEWS is a specialized news site that freely publishes important information on grid-connected storage batteries. It organizes practical information necessary for business, from system revisions, subsidies, grid connections, business development, EPC, procurement, operation, to financial and investment issues, based on primary sources, to support decision-making in the storage battery market.
BESS NEWS will continue to provide free and continuous information on system revisions, market trends, and practical issues related to grid-connected storage batteries and related fields, emphasizing 'information that can be used for judgment on the day it is read.'
[Published Article]
BESS NEWS Published Article Title:
High Voltage by April 2027, Low Voltage Under 50kW by October 2027.
~What You Need to Know Before 'Unconnectable Projects' Emerge Due to JC-STAR Requirements~
URL:
[Main Primary Sources Referenced in the Article]
・Ministry of Economy, Trade and Industry 'About Grid Code'
・Ministry of Economy, Trade and Industry 'About Cybersecurity Measures for Distributed Power Sources'
・Organization for Cross-regional Coordination of Transmission Operators 'About the Requirement for Cybersecurity Measures for Distributed Power Sources (20th Grid Code Study Group Document 4)'
・IPA 'Security Requirement Conformity Assessment and Labeling System (JC-STAR)'
・IPA 'Detailed Information on Security Labeling System (JC-STAR)'
・IPA 'List of Products with Conformity Labels'
[BESS NEWS Editorial Comment]
The truly important point of this theme is that JC-STAR has moved beyond the 'desirable to have' stage and entered the stage where it must be considered a practical condition for new grid connections. Especially for low-voltage systems under 50kW, even though there appears to be a transitional measure until October 2027, in practice, what equipment is subject, when the contract application is made, and whether conformity can be confirmed at that time are more important than the 'completion date.' BESS NEWS will continue to deliver primary source-based explanations that can be used directly for on-site judgment, not just as news, regarding system revisions.
[About WATT-TUNE Co., Ltd.]
WATT-TUNE Co., Ltd. is a wholly-owned subsidiary of Eco-Kaku Co., Ltd., which is part of Technologies Group Co., Ltd. In the distributed energy sector, including low-voltage grid-connected storage batteries, we are promoting initiatives to connect practice and systems through information dissemination, business development, and the establishment of operational structures.
[About BESS NEWS]
BESS NEWS is a specialized news site that freely publishes important information on grid-connected storage batteries. It aims to build an information infrastructure that enables businesses, consumers, investors, and local government officials to make quick and accurate decisions by organizing information related to systems, policies, installation practices, operations, and investment decisions, as much as possible based on primary sources.
[Contact Information for this Matter]
Company Name: WATT-TUNE Co., Ltd.
Location: 1322-9 Takahagi-cho, Sano City, Tochigi Prefecture
Representative: Fukuo Aoyagi, Representative Director
Business Activities: Aggregation Franchise
URL: BESS NEWS https://bessnews.jp/
Mail: info@watt-tune.co.jp
What BESS NEWS focused on this time is not merely an 'announcement of system changes.' The critical practical point is that even for low-voltage systems under 50kW, projects applying for grid connection contracts after the revision will fundamentally be unable to connect generation equipment that does not meet the requirements. Furthermore, the same document anticipates projects with lead times between equipment installation and application, stating that it is desirable to use products compliant with the latest grid connection requirements early. In other words, the crucial date to consider is not just the 'construction completion date' but also the contract application date.
The background to this is the real cyber risks extending to distributed power sources. OCCTO's (Organization for Cross-regional Coordination of Transmission Operators) materials introduce a case where approximately 800 remote monitoring devices for solar power generation facilities were cyber-attacked in May 2024 and exploited for fraudulent online banking transfers. Additionally, these requirements are organized within the grid connection technical requirements stipulated by each general transmission and distribution utility based on OCCTO's 'Transmission and Distribution Business Guidelines.' BESS NEWS has taken this point not as a 'recommendation' but as an issue that must be read as an entry condition for connection practices, and has published an article about it.
The article delves into issues such as the following:
How does the 'transitional measure' for low-voltage systems under 50kW apply to which projects?
Is it sufficient to only look at the PCS (Power Conditioning System)?
How far should one check, including EMS (Energy Management System), BMS (Battery Management System), gateways, and remote monitoring devices?
How much practical significance does a manufacturer's 'planned support' have?
According to official documents, the scope of the requirements is **'control systems with communication functions,'** with PCS, EMS, etc., cited as examples. Furthermore, even IP communication devices that appear to be outside the scope are subject to these requirements if they have functions to control power generation equipment or are directly connected to main equipment. BESS NEWS organizes such difficult-to-read primary information into a format that is easy for on-site personnel to understand.
Regarding JC-STAR itself, BESS NEWS does not stop at merely introducing the system name. According to IPA (Information-technology Promotion Agency, Japan), JC-STAR is a security requirement conformity assessment and labeling system for IoT products, with ★1 and ★2 being self-declaration methods. On the other hand, IPA advises against expressions that suggest acquisition is possible before the conformity label is issued, such as 'JC-STAR conformity planned,' and explicitly states that applications may be rejected depending on the results of the verification process. That is why the article explains that inquiries to manufacturers should not end with 'it's planned,' but must ascertain which equipment will acquire it, whether it has already been acquired, when it is expected to be acquired, and where to confirm this information. IPA also publishes a list of products that have acquired the conformity label.
The aim of BESS NEWS with this article was not to assert a definitive conclusion about the system in a single sentence, but to proactively increase the resolution of confusion that actually occurs on-site.
Is it acceptable to view it as 'still far off because it's 2027'?
Is it acceptable to think 'there's a little more leeway for low-voltage systems under 50kW'?
Is it sufficient to estimate it as 'a complete set of battery storage systems'?
What impact will such discrepancies in judgment have on connection practices and processes later on?
The BESS NEWS article is structured to trace these answers based on primary information.
[This article is recommended for the following people]
It is recommended for developers, EPC and construction companies involved in new grid connection projects for solar power generation and grid-connected storage batteries, manufacturers and distributors handling PCS, EMS, BMS, gateways, remote monitoring devices, etc., and financial/investment professionals who want to understand how system changes will affect investment decisions and due diligence. In particular, practical personnel who feel 'it's still a distant matter because it's a low-voltage system under 50kW' should definitely review this content.
[About BESS NEWS]
BESS NEWS is a specialized news site that freely publishes important information on grid-connected storage batteries. It organizes practical information necessary for business, from system revisions, subsidies, grid connections, business development, EPC, procurement, operation, to financial and investment issues, based on primary sources, to support decision-making in the storage battery market.
BESS NEWS will continue to provide free and continuous information on system revisions, market trends, and practical issues related to grid-connected storage batteries and related fields, emphasizing 'information that can be used for judgment on the day it is read.'
[Published Article]
BESS NEWS Published Article Title:
High Voltage by April 2027, Low Voltage Under 50kW by October 2027.
~What You Need to Know Before 'Unconnectable Projects' Emerge Due to JC-STAR Requirements~
URL:
[Main Primary Sources Referenced in the Article]
・Ministry of Economy, Trade and Industry 'About Grid Code'
・Ministry of Economy, Trade and Industry 'About Cybersecurity Measures for Distributed Power Sources'
・Organization for Cross-regional Coordination of Transmission Operators 'About the Requirement for Cybersecurity Measures for Distributed Power Sources (20th Grid Code Study Group Document 4)'
・IPA 'Security Requirement Conformity Assessment and Labeling System (JC-STAR)'
・IPA 'Detailed Information on Security Labeling System (JC-STAR)'
・IPA 'List of Products with Conformity Labels'
[BESS NEWS Editorial Comment]
The truly important point of this theme is that JC-STAR has moved beyond the 'desirable to have' stage and entered the stage where it must be considered a practical condition for new grid connections. Especially for low-voltage systems under 50kW, even though there appears to be a transitional measure until October 2027, in practice, what equipment is subject, when the contract application is made, and whether conformity can be confirmed at that time are more important than the 'completion date.' BESS NEWS will continue to deliver primary source-based explanations that can be used directly for on-site judgment, not just as news, regarding system revisions.
[About WATT-TUNE Co., Ltd.]
WATT-TUNE Co., Ltd. is a wholly-owned subsidiary of Eco-Kaku Co., Ltd., which is part of Technologies Group Co., Ltd. In the distributed energy sector, including low-voltage grid-connected storage batteries, we are promoting initiatives to connect practice and systems through information dissemination, business development, and the establishment of operational structures.
[About BESS NEWS]
BESS NEWS is a specialized news site that freely publishes important information on grid-connected storage batteries. It aims to build an information infrastructure that enables businesses, consumers, investors, and local government officials to make quick and accurate decisions by organizing information related to systems, policies, installation practices, operations, and investment decisions, as much as possible based on primary sources.
[Contact Information for this Matter]
Company Name: WATT-TUNE Co., Ltd.
Location: 1322-9 Takahagi-cho, Sano City, Tochigi Prefecture
Representative: Fukuo Aoyagi, Representative Director
Business Activities: Aggregation Franchise
URL: BESS NEWS https://bessnews.jp/
Mail: info@watt-tune.co.jp