š Case Study
California Utility-Scale Fire Mitigation Retrofit
Existing BESS lacked NFPA 855ācompliant fire suppression and thermal runaway propagation controls; post-2020 CalFire directives mandated rapid detection, localized inerting, and inter-cell thermal barrier upgradesāyet retrofitting active systems into energized, operational containers required zero downtime, preserved existing UL 9540A test validation, and maintained 99.2% availability SLA.
šļø Project Overview
Retrofit of fire mitigation systems at a 200 MW / 800 MWh lithium-ion battery energy storage system (BESS) located in the Central Valley, California. The facility operates as part of the CAISO grid and supports peak shaving, frequency regulation, and wildfire-related grid resilience. Retrofit scope covered all 48 containerized battery units installed across two phases (2019 and 2021).
šÆ Challenge
Existing BESS lacked NFPA 855ācompliant fire suppression and thermal runaway propagation controls; post-2020 CalFire directives mandated rapid detection, localized inerting, and inter-cell thermal barrier upgradesāyet retrofitting active systems into energized, operational containers required zero downtime, preserved existing UL 9540A test validation, and maintained 99.2% availability SLA.
š§ Design Approach
Phased, container-level engineering: (1) Thermal modeling (ANSYS Fluent) to map hotspot evolution during simulated thermal runaway; (2) Integration of dual-spectrum IR/UV flame detectors with <2s response time; (3) Installation of per-module aerosol suppressant nozzles (K-75/K-85) paired with nitrogen inerting manifolds; (4) Replacement of polyurethane thermal barriers with intumescent ceramic fiber mats (ASTM E136-compliant); (5) Cyber-physical interface with existing BMS via Modbus TCP for predictive suppression triggering.