Energy management and module-level optimisation of load-induced PEMFC degradation in retrofit hybrid maritime power systems

This study presents an integrated energy-management and optimisation framework for retrofitting a real Scandinavian coastal passenger vessel with a Proton Exchange Membrane Fuel Cell (PEMFC)–Battery Energy Storage System (BESS). The framework uses logged power-demand data over a 12-day round-trip mission and combines frequency-based load decomposition, subsystem sizing, and degradation minimisation via Model Predictive Control (MPC). Six frequency-decoupling techniques are benchmarked, identifying the Butterworth low-pass filter as the most balanced method for separating slow-varying and fast-varying load components assigned to the PEMFC and BESS. Two hybridisation strategies are evaluated: constant-load PEMFC operation with battery buffering, and frequency-decoupled operation for practical retrofit sizing. The subsequent MPC-based optimisation demonstrates that dynamic load allocation strongly influences degradation behaviour, with smaller PEMFC modules exhibiting higher cumulative wear due to greater exposure to low-power operation and start–stop events. The study reveals the dynamics of load-induced degradation, offering a pathway towards durable PEMFC integration in maritime applications.