PEM electrolyzer failure scenarios identified by failure modes and effects analysis (FMEA)

Proton exchange membrane (PEM) electrolysis is a promising technology for clean hydrogen production. To support safe deployments of PEM electrolyzers, we performed a failure modes and effects analysis (FMEA) on a lab-scale PEM electrolyzer to identify risk-significant scenarios. We identified 20 failure scenarios leading to a hydrogen release, 46 for an oxygen release, and 67 for hydrogen and oxygen mixing. Hydrogen fires or the collection of hydrogen and oxygen gas poses risk to facility personnel and surrounding equipment. The gas-water separators, pump supplying water to the electrolyzer stack, and electrolyzer stack were found to contribute to the most high-risk scenarios. Identifying these scenarios enables the mitigation of issues seen in early deployments and is a step toward a complete Quantitative Risk Assessment. The results provide a technical basis to support risk-informed safe and reliable deployment and operation of electrolyzer technologies by enabling development of safety plans, design, and operational strategies.