Dynamic Response Analysis of Alkaline and PEM Electrolyzers in Low-Inertia Power Systems: A Comparative Study

In modern power systems, the increased integration of intermittent renewable energies has led to heightened uncertainty and low inertia challenges. Current investments in green hydrogen provides the opportunity of addressing these issues, which not only aid in smoothing renewable energy curves but also help manage low inertia issues in the power system. This paper focuses on modeling two similar plants for Alkaline (ALK) and Proton Exchange Membrane (PEM) electrolyzers, along with their respective power-electronics interfaces for grid connection. The dynamic responses of these plants are analyzed within a low-inertia power system, and a PID controller is implemented to control the frequency response in the presence of the electrolyzers. Simulation results conducted on the IEEE 30-bus test system demonstrate a superior dynamic response of PEM electrolyzers compared to ALK electrolyzers, observed from both power and frequency response perspectives. The results show that the fast response of PEM electrolyzers positions them as a more capable solution for Fast Frequency Response (FFR) services in power systems.