Optimal techno-economic operation of stand-alone hybrid renewable energy system using a bi-level model predictive framework

• HRES with PV-Wind and different types of energy storage • Efficient performance and Optimal sizing of HRES • Optimization using a Bi-level mixed integer nonlinear programming • Real application of a Stand-Alone HRES This paper presents the design procedure and optimization of a stand-alone hybrid renewable energy system (HRES) to supply residential loads. The proposed system includes photovoltaic (PV) panels and wind turbines as principal renewable energy sources. In addition, a hydrogen system, with electrolyzers and fuel cells, and a battery storage system, are also included in the proposed system. A bi-level optimization approach is applied to solve the sizing and energy management problems. The upper level, which addresses the sizing issue, is defined as a mixed integer non-linear programming (MINLP) problem. While the lower level, which defines the energy management strategy issue, is used to achieve minimum operational cost, based on economic model predictive control (EMPC). The optimization structure is developed using the MATLAB environment to solve the bi-level problem and identify the optimal parameter setting. Two configurations have been analyzed: the first one is called the optimal HRES configuration, which includes all types of energy elements, and the second one is called the non-optimal configuration, which misses the wind turbine element. The results record a considerable cost benefit for the optimal configuration, with a total cost of $92,814 compared to $554,980 for the non-optimal configuration. Furthermore, the optimal configuration achieves an ELF of 6.7 × 10⁻¹⁸, which is almost an ideal reliability in energy supply.