Bi-Level Optimization Model of Integrated Biogas Energy System Considering the Thermal Comfort of Heat Customers and the Price Fluctuation of Natural Gas

Biogas is a pervade renewable energy source in rural areas, which can be used to generate power, heating and gas to satisfy the multi-energy needs of users. This paper establishes a bi-level optimization model of integrated biogas energy system considering the thermal comfort of heat customers and the price fluctuation of natural gas. Among them, using the penalty factor to describe the thermal comfort and building the DBN model of natural gas fluctuations. The upper optimization target is the largest profit of the energy agency, and the lower objective is the minimum heating cost considering the penalty factor. Using the Karush – Kuhn – Tucker condition and the big M method, the original lower convex function is transformed into the upper function constraints, making the bi-layer optimization model into a mixed integer programming formulation. The influence of diverse biogas scales and operation modes of the system, fluctuated natural gas price effects and various penalty factors of the user economy and comfort during heating are also analysed