Impact of renewable power fluctuations on PEM hydrogen storage systems: A transient multi-physics modeling analysis

The inherent power fluctuations of renewable energy generation pose significant challenges to proton exchange membrane (PEM) hydrogen storage systems, including unstable hydrogen production, efficiency degradation, and safety risks associated with hydrogen crossover. However, the transient coupling mechanisms through which power disturbances propagate among electrochemical reactions, thermal management, and gas pressurization processes remain insufficiently understood. To address this gap, a transient multi-physics model of a PEM hydrogen storage system integrating electrochemical, thermodynamic, and fluid dynamic couplings is developed using MATLAB/Simulink. Typical power disturbances are represented by sinusoidal and step-change signals, and six representative wind–photovoltaic fluctuation scenarios—including open-terrain wind, offshore wind, and cloudy irradiance conditions—are constructed based on Weibull and Beta statistical distributions. The dynamic responses of hydrogen production rate, cathode pressure, the concentration of hydrogen in oxygen (H 2 -in-O 2 ), water circulation flow, and energy consumption structure are systematically investigated. The results demonstrate that both the amplitude and frequency of power fluctuations significantly affect system stability and energy efficiency. When the fluctuation amplitude increases from ±5% to ±50%, the cathode pressure variation range expands by approximately eightfold, and the peak H 2 -in-O 2 rises to 1.2%. Compared with high-frequency disturbances, low-frequency power fluctuations more readily induce pressure amplification effects, resulting in reduced average system efficiency. Rapid load variations further increase the risks of cathode pressure overshoot and transient hydrogen enrichment. Moreover, wind and solar variability plays a decisive role in system dynamic performance, indicating that differentiated operation and control strategies are required to ensure efficient and safe PEM hydrogen storage operation. • A transient multi-physics model couples electrochemical, thermal, and fluid dynamics in PEM hydrogen storage. • Fluctuation amplitude strongly affects stability, with cathode pressure oscillation increasing eightfold at 50% change. • Low-frequency power fluctuations cause larger pressure swings and reduce system efficiency by about 2%. • Rapid load changes trigger cathode pressure overshoot and transient hydrogen enrichment risk. • Renewable fluctuations drive hydrogen production from 28% to 88% of rated capacity under highly variable weather.