# Day-Ahead Dispatch Model of Electro-Thermal Integrated Energy System with Power to Gas Function
## 1 Introduction  
With new energy utilization receiving widespread attention, the installed capacity of photovoltaic (PV), wind power and other new energy generation system are increasing [1; 2; 3]. It is expected that the installed wind capacity will reach 200 million kW by 2020. However, wind power utilization is often limited due to the unsynchronized construction between wind farms and power grids, as well as the mismatching between wind power characteristics and peaking capability. In some areas, these \"abandoned wind\" phenomena directly lead to energy waste and economic losses. A typical integrated energy system includes natural gas supply, power supply and thermal energy supply, which can increase renewable energy efficiency by means of coordinating and optimizing various energy links in the integrated system. At the same time, developing gas storage technology, power storage technology and heat storage technology in the integrated energy network to form multiple consumptive technology or multiple energy storage technology, can reduce the abandon wind or light. In view of the high cost of large power storage and the relatively low cost of gas storage, gas storage technology can be greatly developed in the integrated system. For instance, based on P2G technology the excess wind power is converted into hydrogen which is mixed with natural gas or used as a material for producing synthetic natural gas. This method will directly reduce the abandoned wind power from the production source. P2G technology is a process of converting electrical energy into gas energy. At valley load period of power output or peak load period of renewable energy output, the excess energy is converted to hydrogen or natural gas stored in the gas storage device. In the event of an electric or heat shortage period, the stored gas transported by natural gas pipelines is converted to electrical or thermal energy to the users, which enhances the ability of the integrated energy system to absorb renewable energyduring valley load periods. P2G technology also increases the role of electro-gas coupling in the system and enhances the coupling between power systems and natural gas systems. Scholars in various countries have carried out many explorations into P2G research. In [4], the economic potential of P2G technology is evaluated. In [5], the potential role of P2G in future energy systems is discussed. And P2G is considered as a storage system with relatively large storage capacity but relatively low efficiency (i.e., energy storage). In [6], the research aims to investigate an innovative biogas upgrading process, based on gas hydrate technology, and combine it with power-to-gas technology to produce additional synthetic methane. In [7], P2G is the way to decarbonize the energy supply chain as a fraction of Hybrid fuels, combination of fossil ones and Renewable Hydrogen, as an immediate responsive storage solution. The authors investigated different urban energy scenarios at RES share increase from 25% up to 50% in the energy mix to highlight strengths and weaknesses of the P2G applications. In [8], the researchers combine P2G with gas turbines to study the influence on abandoned wind power of the system. In [9], P2G technology is considered as energy storage form with long-term and wide area, which achieves large-scale storage and transmission of renewable energy resources. On the side of integrated energy systems, literature [10] introduces the method of modeling, planning and optimization of the regional integrated energy system. In [11], based on the uncertainty of power, gas, thermal loads and wind power, the probabilistic energy flow of integrated energy system coupled by electricity and natural gas is solved. The research work provides some theoretical principle and basis for P2G integration. At present, most of the researches have conducted in-depth analysis of the gas system, power system and thermal system separately, but the coordination analysis of the gas-electricity-thermal integrated system is still insufficient.