Optimal Operation Strategy of Power-to-Gas System with Load Regulation Characteristics Participating in Electricity Spot Market

To address the insufficient consumption of distributed renewable energy, reduce the impact of long-distance transmission on the power grid, and enhance the market competitiveness of user parks with distributed energy resources, an optimal operation strategy for the Power-to-Gas (P2G) system is proposed considering load regulation characteristics to participate in the electricity spot market. First, the P2G system is categorized into two processes based on the products: water electrolysis and methanation. A hydrogen storage tank serves as the linkage facility between the two processes. The water electrolysis process is further divided into two working stages: the unstable operation phase and the stable operation phase. Furthermore, the methanation process is classified into three working states: long-term shutdown, short-term shutdown, and normal operation. The input power requirements and corresponding production characteristics of each stage and state are analyzed. Second, this paper selects the stable operation stage of electrolysis and the operation state of methanation with flexible power regulation capability, establishes a power adjustment model that incorporates the regulation range and speed of power consumption, and analyzes the start-up and shutdown characteristics of the two processes. Third, an operation model is developed for the P2G system that maximizes production efficiency based on the price signals of the electricity spot market. The model is solved using the nonlinear optimization solver Interior Point OPTimizer (IPOPT). Finally, the superiority of the proposed method and model is verified by comparing the power regulation performance of the two production processes under different distributed renewable energy power generation scenarios.