Dynamic Electrical Equivalent Circuit Modeling of the Grid-Scale Proton Exchange Membrane Electrolyzer for Ancillary Services

As the percentage of renewable energy sources grows, excess electrical power from renewables can be converted using electrolyzers to produce hydrogen, which can be stored, and later utilized by industries, homes, or the transportation system. Further, electrolyzers can also be utilized for frequency and voltage control to improve the stability of the power system. In this paper, a novel electrical circuit model for a 400W PEM electrolyzer is designed and validated using the experimental data from a reported paper for a 400W electrolyzer. To demonstrate its adaptive feature, the proposed 400W model is then scaled up to a 1 MW array by series and parallel connections, and the resulting system is validated by comparing it to another reported experimental results of a 1 MW stack. These results reveal that the developed model can reproduce very similar step responses to those obtained from experimental results from the reported 400W electrolyzer and the 1 MW stack. Finally, using the proposed electric circuit model, the step response of the equivalent circuit model to the step-change in the grid frequency has been investigated and the results show that the electrolyzers can respond to frequency step change faster than traditional generators demonstrating that employing electrolyzers can have a great potential to improve frequency stability.