Optimization of a hybrid energy system with/without considering back-up system by a new technique based on fuzzy logic controller

Abstract

The environmental benefits of alternative energy sources, including wind and solar, are the main attraction for both researchers and the public. The use of the photovoltaic and wind systems to generate energy is very unreliable in itself without a back-up system like diesel generators or storage devices like batteries. This work focuses on determining the size of a hybrid energy scheme including the photovoltaic panels and wind turbines with/without considering the backup system to reduce economic costs and increase reliability. Also, sensitivity analysis based on loss of power supply probability (LPSP) has been investigated under different scenarios. According to the main goals, a novel method is proposed based on the integration of fuzzy logic controller and harmony search algorithm. This method will give the optimal size of a hybrid energy scheme based on environmental information (load demand, solar irradiation, and wind speed). In this paper, the fuzzy rules and membership functions are designed to increase the convergence rate and improve the results. According to the results (for LPSP = 1), utilization of a backup system can save the costs up to 24%. For increasing the system reliability by 5%, the system costs will raise up to 36%. The utilization of a backup system reduces the hybrid energy system costs. Thus, the hybrid energy system that consist of photovoltaic panels, wind turbines, batteries, and diesel generators are more affordable than other systems. Moreover, the fuzzy harmony search algorithm leads to more promising results compared to the harmony search algorithm.