News, 24 June 2025
The Central Electricity Authority (CEA) has recently issued draft safety and electrical supply guidelines for Battery Energy Storage Systems (BESS). These guidelines, available on the Mercom India website, cover crucial aspects such as battery chargers, fault tolerance, fire safety protocols, battery management systems (BMS), power conversion systems, and cooling mechanisms. Stakeholders are invited to submit their feedback on these proposed guidelines by July 20, 2025.
Key safety provisions detailed in the draft include:
- Battery Chargers and Fault Tolerance: Chargers must be specifically designed to align with the battery chemistry. The BESS is mandated to have a two-fault tolerance design, allowing it to either continue safe operation or shut down securely even after two independent faults . This robust protection is essential for conditions like overcharge, over-discharge, short circuits, and operation outside specified temperature ranges.
- Fire and Explosion Safety: Comprehensive measures are required across all levels: individual cells, modules, containers, and the overall site installation.
- Battery Management System (BMS): The BMS is critical for monitoring and recording vital parameters such as voltage, temperature, current, and thermal runaway at both cell and module levels. It must trigger visual and audio alarms if any parameter exceeds manufacturer specifications, and automatically halt charging/discharging if temperature limits are surpassed.
- Power Conversion System: This system needs to support fully automatic and unattended operation, including seamless grid synchronization and self-protection against component failures or abnormal conditions.
- Cooling Systems: Coolant lines must be securely routed to prevent leaks near live electrical components. Any failure in the dielectric fluid cooling system should not result in leakage that could lead to cell short circuits or create hazardous conditions within the battery pack.
- Battery Container Design: Containers must be explosion-proof and feature a forced ventilation system with automated louvers to safely release flammable gases and maintain internal pressure. They must also comply with relevant standards for ingress protection and walk-in arrangements .
- Equipment Location: A minimum distance of 7.5 meters is required between battery containers and the nearest exterior wall or roof overhang. If this distance is not achievable, large-scale fire testing is mandatory. A 3-meter separation between battery containers is also required, or alternatively, large-scale fire testing and a two-hour fire-resistance rating for external walls. Noise reduction measures are also necessary in densely populated or critical infrastructure areas.
- Ventilation:Every battery container needs to have systems in place to regulate the concentration of combustible materials as well as sufficient ventilation and cooling to avoid overheating. The system must automatically shut down in the event that mechanical ventilation fails.
- Hazard Detection and Suppression: BESS must include actively monitored systems for detecting smoke, gas, heat, and flame. Containers with a capacity of 200 kWh or more must be equipped with an automatic water-based fire suppression system .
- Other Measures: These include provisions for electrolyte spill containment, emergency lighting in enclosed areas, 1.8-meter high fencing for unauthorized access prevention, and surveillance systems (CCTV, motion sensors, alarms). If a safety issue or anomaly is detected, the affected part of the system must shut down within a preset timeframe. Manual emergency stop mechanisms are also required.
Furthermore, an independent third-party fire safety audit is mandatory for each installation, with the report to be submitted to the Electrical Inspector. The government is also responsible for ensuring fire safety personnel receive specialized training for BESS fire risks, with training guidelines to be issued by the Directorate General of Fire Safety within three months of the regulations’ notification.
