Reliability Evaluation of a Hybrid Renewable Energy System Using Fault Tree Analysis Approach

Most rural communities in Nigeria still face inadequate power supply, while others await connection to the national grid due to their remote locations. To meet the energy requirements in these areas, the adoption of renewable energy sources has become crucial for society and the nation at large. Renewable energy resources are largely attractive because of their availability, environmentally friendly nature, and cost-effectiveness through continuous supply. However, due to their intermittent availability, hybrid renewable energy systems are employed to mitigate the drawback caused by their intermittency. In this study, the reliability of a complex hybrid renewable energy system involving five subsystems components is evaluated. The minimal cut-sets of the complex system were first determined, followed by the construction of the fault tree diagram. The failure variables associated with the parameters of each component were assumed to follow Weibull failure laws. The system's reliability was assessed for various arbitrary parameter values, such as failure rate (λ), shape parameter (β), and operating time (t) of the components. The results show that for λ = 0.01, the system reliability ranges from 0.97474 to 0.84816 for β values from 0.1 to 0.2, and t values from 10 to 20. For λ = 0.02, reliability ranges from 0.96671 to 0.57295 over the same parameter ranges. For λ = 0.03, the reliability varies from 0.95568 to 0.34419; for λ = 0.04, from 0.94058 to 0.19465; and for λ = 0.05, from 0.92004 to 0.10677, with β values between 0.1 and 0.2 and t between 10 and 20. The dynamics of these reliability indices are presented both graphically and numerically, based on arbitrary values of the system components' parameters