An integrated energy system coupled with solar energy and biogas is designed in this study, and a joint optimization method of capacity and operation is proposed. Firstly, a thermodynamic model of biogas production is introduced, and a capacity-operation two-layer optimization model is constructed. The upper layer optimizes the size of the biogas digester and the capacity of energy conversion and energy storage equipment to minimize the annual total cost. The lower layer takes the upper-layer results as constraints to optimize the operation plan of energy conversion and energy storage equipment, minimizing the operation cost. Secondly, by integrating the nonlinear programming method into the genetic algorithm, the model is solved to determine the optimal capacity configuration and operation scheme of the system. Finally, five simulation scenarios are used to verify the effectiveness of the proposed system and the joint optimization method. The results show that the integrated energy system optimized by the proposed method has the best economic performance, and the energy consumption scheme is efficient and reasonable.

renewable energy  /  optimization  /  integrated energy system  /  solar energy  /  biogas