Modelling of Polymer Electrolyte Membrane Electrolyzer Degradation and Reliability

Hydrogen production using electrolyzers can contribute to reduction in global emissions. A Polymer Electrolyte Membrane electrolyzer (PEME) splits water into hydrogen and oxygen, offering advantages in dynamic operation that enables rapid responses to fluctuations in power input and operating conditions. This reduces start-up time and allows immediate hydrogen generation. Ensuring the reliability and safety of PEMEs is critical for efficient hydrogen production. Degradation and failures of electrolysis cells can lead to hydrogen crossover, posing safety concerns and corrosion which reduce gas diffusion and conductivity, affecting performance. Although PEMEs have a lifetime of 40,000-60,000 hours, availability remains low due to frequent operational downtime and maintenance. This paper proposes a Petri net (PN) model which, in addition to reliability assessment, considers the degradation and maintenance processes of the stack. PNs are suitable for modelling complex, concurrent systems, making them ideal for capturing the dynamic interactions within the electrolyzer. By capturing such interactions, the PN approach is used for modelling both normal operations and potential failure scenarios. Such an approach can aid the hydrogen industry in making better asset management decisions, improving electrolyzer availability and safety. It can also inform the risk assessment process, enabling strategic investments in reliability and operational efficiency.

Keywords: Hydrogen, PEM electrolyzer, Degradation, Reliability.