Modelling and Optimization of a Grid-Integrated Hydrogen Energy Storage System for Renewable Energy Smoothing

Abstract

The increasing penetration of renewable energy sources into the modern electrical power system has created significant issues of renewable intermittency, voltage instability and power fluctuation. The PV power generation is strongly influenced by environmental factors like irradiance and temperature, which leads to fluctuations in power output and can adversely impact grid stability and energy management. To overcome these challenges, this thesis proposes the modelling and optimization of a grid-integrated hydrogen energy storage system for smoothing renewable energy and delivering stable power. The proposed system consists of PV array, electrolyzer, hydrogen storage tank, fuel cell, DC bus, and grid interface in MATLAB/Simulink environment. Mathematical models of the major system components were created to study the operational behavior of the integrated renewable-hydrogen system under different load and renewable generation scenarios. A rule-based optimization and energy management strategy was developed to optimize the hydrogen production and fuel cell operation based on the system demand. In times of excess PV generation, the surplus electricity is channeled to the electrolyzer, where it is used to generate hydrogen for long-duration storage. When renewable energy is in deficit, the fuel cell provides electricity to meet the load demand and stabilize the voltage of the DC bus. The simulation results show that the proposed hydrogen-integrated system can successfully mitigate the fluctuations in renewable energy sources, increase the utilization of renewable energy, and enhance the reliability of the system. The integrated operation of the electrolyzer and fuel cell mitigated the intermittency effects of renewables, enhanced the voltage regulation of the DC bus, and minimized excess renewable energy curtailment. Moreover, the hydrogen storage system demonstrated a reliable long duration energy balancing capability, which was better than traditional short duration storage methods. The results show that hydrogen energy storage can effectively enhance the flexibility, stability and sustainability of future smart grid systems with high penetration of renewable energy, and provide efficient management of renewable energy and grid support operation.