Experimental Investigation and Parametric Optimization of a Photovoltaic–Electrolyzer–Fuel Cell–Battery Hybrid System

Abstract

This study presents the experimental investigation and parametric optimization of a photovoltaic–electrolyzer–fuel cell–battery hybrid energy system for sustainable hydrogen production and utilization. The proposed system integrates a photovoltaic module, an alkaline electrolyzer, a proton exchange membrane (PEM) fuel cell, a battery unit, and an electronic energy management system (EMS) to ensure stable, reliable, and efficient operation. The effects of electrolyte type, electrolyte concentration, and operating temperature on hydrogen production and overall system performance were systematically investigated. Key performance indicators, including hydrogen production rate, energy efficiency, Faradaic efficiency, and power output, were evaluated under different operating conditions to identify the optimal operating parameters. The results indicate that increasing electrolyte concentration enhances hydrogen production through improved ionic conductivity and reduced internal resistance, while operating temperature significantly influences electrochemical reaction kinetics. Among the tested conditions, a 1.5 M KOH electrolyte at 60°C provided the best overall performance, yielding the highest hydrogen production rate and energy efficiency. KOH consistently outperformed NaOH because of its higher ionic mobility and lower internal resistance. The study adopts an experimental parametric optimization approach rather than a numerical optimization framework, enabling the identification of optimal operating conditions within safe and practical limits. The implemented EMS effectively contributes to stable system operation by regulating voltage and current fluctuations, thereby improving operational reliability. The findings provide experimentally validated insights into the design, optimization, and operation of hybrid renewable hydrogen energy systems and highlight the importance of electrolyte selection and operating conditions in achieving efficient system performance. The results provide practical guidance for the design and optimization of sustainable hydrogen-based hybrid energy systems.