Modeling the dynamic electrical behavior of high temperature electrolysis for hydrogen production

摘要

Power-to-gas (P2G) plays an important part in the concept of multi-energy system by functioning as interaction points where hydrogen or synthetic natural gas is produced by intermittent electricity generated from massive renewables. In P2G implementations, electrolysis process is the core section to convert electrical energy into gases. However, the dynamic model of electrolyzer is rarely studied from the electrical perspective even though P2G has been recognized as a rapidly growing load in renewable power systems. The existent models are either based on distributed details with high complexity, or derived from static performance without dynamic considerations. This paper proposes a state space model of high temperature electrolysis for hydrogen production to provide a meaningful reference for P2G control and multi-energy system operation. The model complexities are greatly reduced by simplifying physical properties with little impacts to the electricity side. Meanwhile, the system inertia due to gas dynamics and the nonlinearity due to electrochemical reactions can still be described accurately by the proposed electrolyzer model. In the case study, a detailed bondgraph electrolysis model is used as a benchmark for comparative verification of the proposed model.