The Electric Power Research Institute (EPRI), a global leader in BESS incident tracking and analysis, has reshaped industry understanding with its 2024 whitepaper, Insights from EPRI’s Battery Energy Storage Systems (BESS) Failure Incident Database, Analysis of Failure Root Cause. Contrary to long-held beliefs that thermal runaway from cell defects is the main culprit in BESS incidents, EPRI found that most failures stem from elsewhere.
According to the aforementioned report, 89% of failures involved controls (battery and energy management systems) or the balance of system (BOS)—everything except the cells and controls. In 86% of cases, the root cause was not a battery manufacturing defect, but poor assembly, flawed design, or operational errors.
In response, EPRI recommends the following key mitigation steps: adherence to codes and standards, careful vetting of suppliers, factory acceptance testing, and environmental monitoring to identify issues (e.g., water ingress, excessive heat or humidity, and equipment overheating) before they escalate.
