For its operation configuration, the characteristics of the multi-energy federation of HS in energy storage (ES) systems are non-negligible ( Shao et al., 2021). The second aspect is the optimization for hydrogen storage (HS) configuration.

Moreover, it is necessary to consider the multiple physical coupling for building the SOEC model ( Cheng et al., 2017). For the PEMEC model, the non-linear relationship between hydrogen production and power accommodation also needs to be considered ( Gahleitner, 2013). The AEC is used to consider the coupling between electricity and heat and between electricity and hydrogen ( Li et al., 2019). Firstly, the state-of-art for three P2H models is discussed in details. The current research on P2H-containing microgrids (P2H-MGs) mainly includes three aspects: the operation characters and models of P2H, the optimization for hydrogen storage (HS) configuration, and the market operation of P2H-MG. Moreover, its speed of start and shut is slow ( Mathiesen et al., 2013 Ban et al., 2017 Reddy et al., 2018 Wang et al., 2019 IEA, 2020). However, the choice of materials is rare for its high-temperature working environment. The SOEC has the highest energy utilization efficiency. However, its electrode is made of precious metal, and the proton exchange membrane needs to be replaced frequently, which makes it more costly. The PEMEC has good adaptability to RE, and its dynamic response ability is the strongest. However, the security of AEC is poor because of the corrosive liquid inside. Among the three, the AEC has the highest maturity, the lowest equipment cost, and the longest lifespan. There are three main types of mainstream P2H cells: alkaline electrolysis cell (AEC), proton exchange membrane electrolysis cell (PEMEC), and solid oxide electrolysis cell (SOEC). With the development of P2H technology, the potential application of hydrogen as a terminal energy source is gradually developed. However, there are three difficulties at present: the first is to propose a reasonable method of flexible resource allocation in an MG ( Murty and Kumar, 2020), the second is to propose a unified model suitable for multiple types of P2H systems, and the third is to solve the problem of multi-market equilibrium (ME) caused by multi-energy coupling. Thus, it is significant to study the operation and transaction methods of microgrid (MG) with a power-to-hydrogen (P2H) system ( Pan et al., 2020). Electro-hydrogen coupling is conducive to the cascade utilization of energy, which has a better effect on improving the accommodation of RE than the widely used electrochemical energy storage. Hydrogen energy has the advantages of high density, cleanliness, and efficiency. Renewable energy (RE) is helpful to alleviate energy and environmental pressures, but the uncertainty and randomness of wind power have led to large-scale wind curtailment at present ( Xie et al., 2019). Finally, case studies based on an IEEE 14-bus system are conducted to validate the proposed model, and the results show that the microgrid with a P2H system could gain more profits and help increase the renewable penetration.

Then, the diagonalization algorithm is adopted to solve the multi-market equilibrium problem. Secondly, an electricity market–clearing model and a hydrogen market model are constructed at the lower level. Firstly, a microgrid operation model applied to different P2H systems including an alkaline electrolysis cell (AEC), a proton exchange membrane electrolysis cell (PEMEC), or a solid oxide electrolysis cell (SOEC) is proposed at the upper level. The proposed bi-level equilibrium model is beneficial to minimize the energy cost of microgrids. This paper conducts unified modeling for different types of P2H systems and considers the multi-energy trading in a hydrogen-coupled power market. The adoption of power-to-hydrogen (P2H) system in a microgrid (MG) can mitigate the renewable curtailment by hydrogen conversion and storage. The uncertainty and volatility of wind power have led to large-scale wind curtailment during grid connections. 2School of Electrical and Electronic Engineering, North China Electric Power University, Beijing, China.1State Grid Zhejiang Electric Power Co., Ltd., Lishui Power Supply Company, Lishui, China.Hongxin Liu 1, Yueyao Wang 2, Feifei Xu 1, Mengkai Wu 1, Kai Jiang 2, Xiaohe Yan 2* and Nian Liu 2

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