Electrolysers: A Review on Trends, Electrical Modeling, and Their Dynamic Responses

The global movement towards high integration of renewable energy sources into power systems to combat climate change underscores the importance of clean energy sources in sustainable development of future energy systems. Simultaneously, hydrogen is gaining prominence as a clean fuel, particularly in sectors like industry and transportation. However, the intermittent nature of renewable energies poses challenges for demand-supply balance and grid stability, necessitating efficient storage solutions. Additionally, the hydrogen economy introduces a new dimension to the challenge of power system balance management. In terms of electrical modeling, particularly for power system stability analysis, dynamic models of electrolysers are essential. Water electrolysis, powered by surplus renewable energy, has emerged as a promising method for hydrogen production, fostering advancements in sustainable energy practices. This paper provides an overview of electrolysis, exploring the electrical behavior of Alkaline, proton exchange membrane, and solid oxide electrolysers, while also categorizing them from a modelling perspective. Respectively, it examines the electrical modeling of electrolysers, encompassing three main formats: electrical equivalent circuit (EEC), mathematical formulation (MF), and block diagram (BD) presentation. Additionally, this paper investigates the dynamic responses of Alkaline and proton exchange membrane electrolysers, identified as the most suitable types for integration into power system dynamic studies. Through a review of existing literature and categorization of models, this paper aims to offer a comprehensive understanding of electrolyser behavior and dynamics in operation of power grids.