Operational flexibility analysis of alkaline electrolyzers integrated with a temperature-stabilizing control

Abstract

Alkaline electrolyzers (AELs) have emerged as promising candidates for providing flexible grid services. However, a comprehensive understanding of their operational flexibility has been hindered by a lack of consideration of their thermodynamics in previous studies. To address this limitation, this paper presents comprehensive models that analyze the impact of AEL thermodynamics on their operational flexibility. Specifically, a closed-loop thermal model with temperature-stabilizing control is established to capture the temperature evolution, followed by the development of a temperature-dependent U–I model to characterize the influence of temperature on electrical performance. Case studies are conducted to simulate a practical 26 kW AEL facility using Matlab/Simulink. The results demonstrate that the proposed temperature-stabilizing control effectively maintains the temperature at the setpoint when adjusting the power consumed by AELs. Consequently, the power regulation range of AELs increases from 7.4 kW to 16 kW, compared to a simple control that fixes the cooling water flow at 0.02 m3/h. While increasing the fixed water flow to 0.05 m3/h can also enhance the regulation capacity, the proposed control ensures higher system efficiency than that of the fixed flow control. Moreover, the temperature-stabilizing performance of the controller is influenced by the cooling system’s parameters. Hence, a coordinated design approach between the cooling system and temperature controller is recommended to achieve favorable temperature-stabilizing performance.