Advanced modeling of PEM electrolyzers for microgrid systems: Incorporating electrochemical and thermal models

Incorporating PEM electrolyzers (PEMElz) into microgrid systems presents a promising avenue for utilizing surplus renewable energy to produce hydrogen while meeting the system operation requirements. The accurate emulation of the behavior of PEMElz in such systems requires a detailed representation of their electrochemical and thermal characteristics. Yet modeling these characteristics optimally poses a challenge due to their inherent complexity, characterized by multivariate, non-linear, and multi-modal characteristics. To address this challenge, this paper proposes an advanced approach to model PEMElz by introducing general forms for the integrated electrochemical and thermal model based on a set of optimally identified parameters. The introduced general forms are generated using an n-dimensional polynomial fitting process for a set of optimally identified parameters, which are determined using the Partial Reinforcement Optimizer (PRO) under various temperature and pressure levels. These general forms provide a reliable PEMElz model to adapt to any temperature and pressure operating conditions. The proposed approach's effectiveness in capturing the static characteristics of PEMElz is verified by analyzing polarization and thermal curves across multiple operating conditions. Furthermore, the proposed general forms are implemented in Matlab/Simulink to emulate the PEMElz behavior when it is incorporated into a microgrid dominated by high penetration levels of variable generation resources such as solar photovoltaic (PV). This demonstration highlights the direct relevance and tangible impact of the proposed general-formulated model based on the optimal identified parameters approach in various operating scenarios.