Zero-dimensional dynamic modeling of PEM electrolyzers

The transition to a low-carbon system foresees the introduction of hydrogen as a clean energy vector. Electrolyzers play a key role in its production from renewable energy, and PEM technology seems the most promising alternative thanks to efficiency, flexibility and compactness. Modeling the device dynamic behavior allows investigating its combination with renewable electricity sources. A dynamic 0D model is developed using Aspen Custom Modeler, including a detailed description of the various phenomena involved in the electrochemical process. General formulations are implemented and multiple options for correlations are present, when available. The model is validated against available literature data, showing an appropriate reconstruction of the cell behavior. Unsteady behavior is studied and the role of thermal capacity is shown, under a test-case with a simple operating input profile.