Overview
We have compiled frequently asked questions about high-voltage grid-scale BESS. Please review these first. If you have further questions, do not hesitate to contact us.
Frequently Asked Questions
Products & Technology
Q1. What are TDS (Tokyo Densetsu Service) and NEXTES?
A. TDS (Tokyo Densetsu Service Co., Ltd.) is a BESS business company within the TEPCO Group. It provides integrated management from design and construction through maintenance and monitoring, offering a 20-year capacity guarantee (under a maintenance service contract). NEXTES (NEXTES Co., Ltd.) is a technology company holding patents in battery control technology (active balance technology). It manufactures and supplies battery systems that achieve a lifespan approximately 10 times longer than conventional systems.
Q2. What is KHK certification and why is it important?
A. KHK certification indicates that the fire-resistant storage enclosure has been tested and certified by the High Pressure Gas Safety Institute of Japan (KHK). This certification is required to comply with the Fire and Disaster Management Agency notification issued in July 2024 (Fire Hazard No. 200). Using KHK-certified fire-resistant enclosures is expected to: ease the combined-volume calculation method for electrolytes, improve the likelihood of installation in urbanization control zones, and streamline fire department consultations. The key distinction from products claiming to be "KHK-equivalent" lies in whether a third-party evaluation test report exists.
Q3. What is active balance technology?
A. Active balance technology corrects variation in the state of charge (SOC) among battery cells. In conventional BESS, overall capacity is limited by the most degraded cell. NEXTES's active balance technology (ACB/AMB) resolves voltage differences between cells and modules at approximately 10 times the capacity of conventional systems. This minimizes the impact of degraded cells, enabling long-term operation exceeding 20 years. Additionally, the IHS technology allows pack replacement while the system is running, minimizing maintenance downtime.
Q4. What is the JC-STAR★1 compliance label?
A. JC-STAR is a security requirements compliance label program operated by IPA (Information-technology Promotion Agency, Japan). Level 1 or above will be required for new grid-connected projects from April 2027 onward (low-voltage from October 2027). REVIX JAPAN's high-voltage grid-scale BESS has already obtained JC-STAR compliance for all major system components — BMS, PCS, and EMS (controller) — enabling smooth compliance with subsidy application requirements and regulatory standards.
Revenue & Investment
Q5. How much revenue can I expect from the frequency regulation market?
A. Because revenue varies significantly based on market prices, bid award rates, utilization rates, aggregator fees, and other factors, it is difficult to provide a single answer. We provide detailed revenue projections on an individual basis during consultations. Please contact us first, and we will present simulations during our meeting.
Q6. Can BESS participate in the capacity market?
A. Yes, high-voltage grid-scale BESS can participate in the capacity market. The market is operated by OCCTO (Organization for Cross-regional Coordination of Transmission Operators) and provides capacity payments for supply capacity four years in advance, functioning as a stable revenue source in addition to frequency regulation market income.
Q7. Are subsidies available? Can you handle the application on my behalf?
A. Subsidy programs such as SII's "Grid-Scale BESS Introduction Support Program" may be applicable. Please consult with us individually regarding application support. Note that subsidy adoption is subject to screening and is not guaranteed.
Q8. Can BESS be added to an existing FIT solar power plant?
A. Yes, it is possible to add BESS to a solar power plant currently under or after its FIT period, and we can propose a revenue improvement strategy combining this with FIP conversion. The project may also qualify for the FY2025 supplementary budget renewable energy co-located storage subsidy, so please consult with us for details.
Installation & Permitting
Q9. Can BESS be installed in urbanization control zones?
A. The use of KHK-certified fire-resistant enclosures has expanded the range of permissible installation locations. However, final judgment requires consultation with the relevant local government and fire department. Please consult with us regarding individual site conditions.
Q10. Can I choose my own construction contractor?
A. Yes, it is possible to engage a separate contractor for the construction work. You may use TDS's one-stop service or select an EPC contractor independently. Please consult us for details.
Q11. How many months does it take from implementation to revenue generation?
A. This varies depending on site conditions, the status of the grid interconnection application, and permit acquisition, but the general estimate is 12–18 months. The processing status of the grid interconnection application has a significant impact, so we recommend initiating the process early.
Warranty & Maintenance
Q12. What does the 20-year warranty cover?
A. When a TDS maintenance service contract is executed, BESS capacity is guaranteed to remain at or above 70% of its initial value for 20 years from the start of commercial operation (20-year capacity guarantee at 70%). Specific warranty details are subject to the individual contract.
Q13. How quickly does REVIX JAPAN respond to failures?
A. Under TDS's 24/7/365 monitoring system, initial response begins within 30 minutes of an alert. Primary response (on-site dispatch, fault isolation, and temporary recovery) targets completion within 2 business days, and secondary response (parts replacement and repair) targets completion within 5 business days.
For Those Who Want to Learn More
For Those Who Want to Learn More
High-Voltage BESS Revenue Model Details → | Contact Us →
Still have questions? Feel free to consult us →
Ready to Get Started?
Have questions or want to request materials? Our team is here to help.
Contact Us (Free) View All Services