Decentralized Green Hydrogen Energy Systems: Optimizing 5kW Electrolyzer-Fuel Cell Integration with Metal Hydride Storage for Off-Grid Homes

Abstract

This paper presents the design and computational analysis of a decentralized green-hydrogen energy system that was designed to be used in off-grid residential setups in the southern region of Libya. The suggested architecture includes a 2kW photovoltaic array, a 5kW proton-exchange membrane (PEM) electrolyzer, metal-hydride hydrogen storage, and a 1kW PEM fuel cell that will be integrated under an Energy Management System (EMS). The results of simulation done in MATLAB/Simulink supports the robust operation of the system with autonomy horizon of 24-36 hours, load coverage of more than 95% and a round-trip electrical efficiency of between 27 to 32 % (lower heating value) at different levels of solar irradiance. The safety tests prove that the triggering of hydrogen-leak detection and mitigation systems is completed within 3s, hence meeting the ISO requirements outlined in ISO 14687. Techno-economic studies provide a cost of electricity that is levelized at USD 0.25-0.30/kWh, making the offered solution quite competitive with respect to the traditional diesel generation. Together the findings support the feasibility of the hydrogen-based microgrids as a solid, clean energy source to support rural households in Libya, and thus contributing to the further implementation of Sustainable Development Goal 7.