Research On Operation Optimization And Optimal Configuration Of Hydrogen Energy Storage In Integrated Energy Systems With Hydrogen Production From Wind Power

The problem of wind power curtailment is the main problem in the rapid development of wind power in China.How to take measures to improve the current situation of wind power consumption has been widely concerned by the industry.The adoption of integrated energy system architecture and the development of multiple conversion technology can improve the local consumption capacity of wind power.This paper focuses on two ways to realize the local consumption of wind power,which are based on the technology of hydrogen production by water electrolysis:（1）Wind power is used to produce hydrogen,and then hydrogen is converted into methane,the terminal product of the system,and the whole conversion process is realized by the Power to Gas（P2G）equipment;（2）Wind power is used to produce hydrogen,and the hydrogen is stored in the hydrogen storage tank.At the appropriate time,the hydrogen stored in the hydrogen storage tank is converted into stable electric energy through hydrogen fuel cell,and the whole conversion process is realized by the hydrogen energy storage equipment.However,when describing the conversion process of the P2G equipment or the hydrogen storage equipment,the existing research rarely comprehensively considers the reaction mechanism and conversion loss of hydrogen production by water electrolysis,which leads to the failure of the P2G equipment to realize the maximum conversion of wind power when participating in the system operation optimization,and also leads to the economic reduction of putting the hydrogen storage equipment into the system to absorb wind power.Therefore,based on the analyisis of the operating characteristics of the water electrolysis equipment and modelling,this paper focuses on operation optimization and optimal configuration of hydrogen energy storage in integrated energy systems with hydrogen production from wind power.Firstly,a mathematical model considering the operation characteristics of the water electrolysis equipment is established.According to the electrochemical reaction process of the water electrolysis equipment,the nonlinear equation including input power,hydrogen production power and operating temperature is obtained.According to the heat transfer process of the water electrolysis equipment,the heat balance equation is obtained.The results show that the proposed model can describe the variation characteristic of the hydrogen production efficiency under different operating conditions,and distinguish the heat loss in the water electrolysis equipment from the waste heat that can be reused,which can be used as the theoretical basis for further research.Then,in view of the problem of how to achieve the maximum conversion of wind power when the P2G equipment participates in the operation optimization of integrated energy systems,the optimal operation strategy of integrated energy systems with hydrogen production from wind power is proposed with the combination of the P2G equipment and the CO₂-based electrothermal energy storage.In the design of the combined mechanism of the P2G equipment and the CO₂-based electrothermal energy storage,the excess heat generated in the process of producing hydrogen from wind power in the water electrolysis equipment is considered,and the hydrogen production process,the reuse process of waste heat and the methanation reaction process of hydrogen and CO₂ are coordinated.On this basis,the optimal operation model of integrated energy systems with the minimum total operation cost as the optimization objective is constructed.A linearization method is proposed to deal with the nonlinear equation of the water electrolysis equipment without introducing the coupling constraints of integer variables.Simulation calculations are carried out using actual system data.The results show that the proposed model can realize the maximization of wind power conversion efficiency and the economic operation of integrated energy system,and the proposed linearization method reduces the solution time of the model compared with the fragmented linear region method.Finally,aiming at the problem of how to put the hydrogen storage equipment into the system to absorb wind power in the most economical way,a bi-level optimal configuration model of the hydrogen storage equipment in integrated energy systems considering the change of hydrogen production efficiency is proposed.The upper model describes the capacity configuration problem of the hydrogen energy storage equipment.The lower model considers the variation characteristics of hydrogen production efficiency of the hydrogen storage equipment under different operating conditions when describing the optimal operation of integrated energy systems with the hydrogen storage equipment.A Data-driven Optimization of bi-level Mixed Integer NOnlinear problems（DOMINO）algorithm is proposed.By collecting data samples and constructing surrogate functions,the original bi-level optimization model is fitted to a single-level optimization model with only the original upper level decision variables,and the configuration results of the hydrogen storage equipment are directly obtained.Simulation calculations are carried out using actual system data.The results show that the proposed model can realize the economy of putting hydrogen storage equipment into the system to absorb wind power,and the proposed DOMINO algorithm is stable and effective in solving the bi-level optimization model.