Large Battery System Losses 2020 - 2025
This document, titled "Post-Incident Analysis: Lessons from $1.5B+ Li-Ion BESS Losses," offers a crucial look into the safety challenges facing the rapidly expanding Battery Energy Storage System (BESS) industry. Authored by John Munno in November 2025, the analysis highlights the severe risks that have emerged as BESS capacity skyrocketed from 5 GW in 2020 to 54 GW in 2025.Key Takeaways and Scope:The report investigates over 50 major BESS fires between 2020 and 2025, which collectively resulted in total losses exceeding $1.5 billion—covering property damage, downtime, and cleanup costs. Crucially, these incidents also incurred a devastating human toll, contributing to more than 10 deaths and 50 injuries globally.The analysis examines high-profile incidents across North America, East Asia, Europe, and Australia. Specific case studies reveal systemic failures and profound environmental and safety impacts:• Moss Landing, California (January 2025): A fire at the Vistra 300 MW facility—the world's largest—caused over $100 million in damages. Investigations suggested cell defects or overheating exacerbated by dense packing, and found that clean agent suppression failed to cool the cells. Post-incident soil and water tests confirmed elevated levels of cobalt, nickel, and manganese (heavy metals) that exceeded EPA levels, resulting in health complaints and contamination risks.• Moorabool, Australia (Victorian Big Battery, July 2021): This fire, which occurred during commissioning, was traced to a coolant leak that caused a short circuit and subsequent thermal runaway. The firmwares lacked essential isolation alarms, leading to rapid propagation.• Beijing, China (April 2021): An explosion during response efforts resulted in two firefighter fatalities. The cause was identified as cascading thermal runaway combined with poor ventilation, which allowed explosive gases (H2, CO) to build up.Root Causes and Recommendations:The source identifies common themes and root causes driving these catastrophic failures:1. Thermal Runaway Triggers: 60% of incidents stemmed from defects or overcharge, while leaks accounted for 30%.2. Propagation Modes: Fires typically spread via heat conduction through cell shells and by the release of explosive atmospheres generated by gases like H2 and HF.3. Mitigation Failures: While suppression systems (like clean agents) can put out flames, they often fail to provide necessary cooling to prevent thermal runaway cascades.The report concludes with critical lessons emphasizing Prevention Over Reaction and the need for Layered Defenses:• Technology & Monitoring: Battery Management Systems (BMS) must be updated to monitor at the cell level to isolate anomalies early (a lesson learned after the Moorabool fire).• Suppression: No single suppression method is sufficient; systems must combine detection, venting, and cooling, recognizing that water-based suppression, though risking shorts, is effective in prolonged events (like the Chandler, Arizona, fire).• Safety & Environment: There is a mandate to monitor toxic releases (such as HF and heavy metals) and implement secondary containment for runoff to manage environmental contamination, a key finding following the Moss Landing incident.• Response: Emergency Response Plans (ERPs) must specifically address deflagration risks, and remote tools or robots should be utilized for high-risk actions.Overall, this analysis stresses that the rapid scaling of BESS technology is currently outpacing safety standards and requires urgent, international failure data sharing and mandatory site-specific Hazard Mitigation Analyses (HMA).
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