System modelling and sizing optimization of pem-integrated hybrid energy storage for data centre resilience

This paper presents a modelling and optimization framework for a hybrid electrochemical energy storage system (HESS) to enhance data centre power resilience. The system integrates lithium-ion batteries (LIB) and a proton exchange membrane (PEM) electrolyser, supported by photovoltaic (PV) generation and a hierarchical control algorithm for both grid-connected and islanded operation. A MATLAB/Simulink-based environment with Python optimization uses real meteorological data from England and a synthetic data centre load profile. Simulation results for representative days indicate that increasing battery discharge power and storage capacity significantly reduces unmet load, with diminishing returns beyond 2,000 kWh of combined storage. At 2,000 kWh, doubling discharge power from 250 kW to 500 kW lowers unmet load from 4,800 kWh to 2,100 kWh (56% reduction), whereas a similar increase in charge power improves performance by <15%. PEM electrolyser and fuel cell ratings affect resilience under limited storage but have reduced impact as capacity grows. The framework provides quantitative guidance for optimally sizing hybrid storage systems to balance reliability, responsiveness, and efficiency in mission-critical applications to data centre.