Energy Management and Techno-Economic Optimization of an Isolated Hybrid AC/DC Microgrid with Green Hydrogen Storage System

Abstract-This paper proposes a hybrid AC/DC microgrid consisting of Photovoltaics (PV) panels, wind turbines (WT), a diesel generator (DG), and a hydrogen storage system. An energy management system (EMS) algorithm using MATLAB and Simulink was designed to efficiently manage equipment in the Hybrid Microgrid with aim of maximizing the contribution of renewable sources and minimizing the operation of the diesel generator. A sensitivity analysis of the installed capacity for both PV and Wind was performed and it was found that the optimum ratings were $300 \mathrm{~kW}$, and $200 \mathrm{~kW}$ for the $P V$ and Wind respectively. The optimum size of the tank to achieve the minimum levelized cost of electricity (LCOE) was determined to be $40 \mathrm{~kg}$ of stored H2, this would achieve an LCOE of $1.565 \mathrm{EGP} / \mathrm{kWh}$ which is lower than the LCOE of $2.213 \mathrm{EGP} / \mathrm{kWh}$ in case the load is completely dependent on the diesel generator. The optimum ratings of the electrolyzer, fuel cell, and diesel generator were found to be $150 \mathrm{~kW}, 100 \mathrm{~kW}$, and $250 \mathrm{~kW}$ respectively. In addition, a sensitivity analysis was carried out for different parameters of the system such as project discount rate and annual increase rate in fuel price. Moreover, the carbon dioxide $\left(\mathrm{CO}_{2}\right)$ emissions of the load on the diesel generator alone and the micro-grid are $9.187 \times$ $10^{5} \mathrm{~kg} /$ year and $2.557 \times 10^{5} \mathrm{~kg} /$ year respectively. Using the proposed sizing of the micro-grid leads to a decrease in emissions by around 72.44 % per year.