A multi-objective optimization model for sizing an off-grid hybrid energy microgrid with optimal dispatching of a diesel generator

Abstract

The paper presents a multi-objective optimization model for sizing and operating a hybrid energy system consisting of solar photovoltaic, wind energy, diesel generator, and battery storage. A new concept of optimizing the diesel generator loading percentage has been introduced. Also, the introduced battery management criteria will enable an adaptive operation hours of the diesel generator while regulating the battery state of charge. The proposed optimization model aims to minimize the total investment cost, operation & maintenance cost, and system’s carbon emissions. The number of PV panels, number of wind turbines, rated diesel generator capacity, rated battery capacity, and optimal loading percentage of the diesel generator will be optimized. The multi-objective optimization will be done using the Genetic Algorithm using MATLAB software. Obtained results are presented in a Pareto optimal chart for better analysis. The fuel cost per day, the levelized cost of electricity, the diesel generator on hours, and the emission factor of the hybrid system have been determined for each optimal output. A comparison was carried out with a previously proposed study and found that the proposed method increases the lifetime of the diesel generator by 42.9%. The optimal loading percentage of the diesel generator is found to be 75%. The proposed optimization model reduced the total cost and carbon emissions of the hybrid energy system by 3.5% and 0.7%, respectively. The levelized cost of energy and the payback period of the proposed hybrid microgrid system are 0.16 USD/kWh and 8 years, respectively, which verify that the proposed system is economically feasible.