Dynamic degradation-based sizing and energy management of hydrogen-assisted hybrid microgrids

The long-term energy management and optimal sizing of hybrid microgrids are essential for ensuring both economic feasibility and operational reliability. This study proposes a comprehensive sizing framework for a microgrid integrating photovoltaic arrays, wind turbines, a battery energy storage system (BAT), a proton exchange membrane fuel cell (PEMFC), a PEM electrolyzer (PEMEL), and a hydrogen storage tank. Unlike conventional approaches that assume fixed degradation rates and replacement periods, the proposed model dynamically simulates the simultaneous degradation of the BAT, PEMFC, and PEMEL to better reflect real operating conditions. Detailed component models are adopted for the PEMFC, PEMEL, and battery. The PEMFC model incorporates both transient and cyclic degradation mechanisms. The PEMEL model accounts for catalyst and membrane deterioration. The battery model considers both calendar aging and cycle-related degradation. The optimization problem minimizes the levelized cost of energy (LCOE) using the cuckoo catfish optimizer (CCO). Five case studies were performed to assess the individual and combined effects of component degradation on system configuration and economic performance. The findings from a real case study reveal that neglecting degradation models can result in underestimated costs. When all degradation effects were considered simultaneously, the LCOE increased by up to 32%, and the payback period was extended by 22.2%. Component lifetimes were also affected by grid import restrictions, varying by up to 18.2% for the PEMFC, 3.6% for the battery, and 23.7% for the PEMEL. The CCO algorithm demonstrated higher solution accuracy and achieved a robustness level of 80% across all cases.