Optimal and reliable design of stand-alone hybrid renewable energy systems: A multi-objective approach

This study presents solutions for multi-objective, multi-constraint optimization for both photovoltaic (PV) and photovoltaic/thermal (PV/T) stand-alone hybrid renewable energy systems (SA-HRES). The main objective is to optimize the size and improve the reliability of SA-HRES, which relies exclusively on renewable resources for hydrogen production. To solve the problem, an optimization algorithm based on Non-Dominated Sorting Genetic Algorithm-II (NSGA-II) was proposed and a new power management strategy (PMS) was developed. The reliability index, known as Power Loss Probability Percentage (LPSP), serves as both an objective function and a constraint. The waste energy percentage (PEW) is evaluated as a constraint to ensure that system efficiency remains within specified limits. Among the Pareto optimal solutions that satisfying the constraints of 10% LPSP and 5% PEW, the lowest PEW solutions for PV SA-HRES are $9388.5 with a PEW of 4.32% and LPSP of 6.0%. For PV/T SA-HRES, these values are $9211.6, 3.85%, and 6.9%, respectively. Despite similar annualized cost of system (ACS) values, the PV/T solution, which uses fewer PV/T, has an LPSP with a negligible difference and a lower PEW compared to the PV solution. This suggests the potential benefits of using PV/T instead of PV in HRES, offering improved efficiency and reliability.