Design of an optimum hybrid renewable energy system considering reliability indices

In this paper, a hybrid wind/photovoltaic/battery generation system is designed. The aim of design is to minimize the annualized cost of the stand-alone system over its 20 years of operation. The optimization problem is subject to economic and technical constraints. System costs involve investments, replacements, operation and maintenance as well as loss of load costs. The technical constraint, related to system reliability, is expressed by the equivalent loss factor. The reliability index is calculated from component's failure, that includes wind turbine, PV array, battery and inverter failure. In this study, hybrid generation systems under different design scenarios are designed based on proposed approach. Finally, hybrid system is selected as the best configuration that has minimum cost and can satisfy the constraints. PSO algorithm is used for optimal sizing of system's components. As a result, the optimum PV number, wind turbine number, battery number and inverter capacity are obtained. The characteristics of components are commercially available and this study is performed for the region in south- west of Iran.