Grid ancillary services using electrolyzer-Based power-to-Gas systems with increasing renewable penetration

•Improved grammar, sentence structure, and overall readability throughout the manuscript.•Clarified the type of electrolyzer (proton-exchange membrane) used and its capabilities for fast response times.•Added explanation about existing markets and applications for power-to-gas systems.•Clarified the opportunities and challenges of long-distance hydrogen transportation and storage.•Revised the review section to add more structure and details, including a summary diagram.•Clarified the contributions of this work compared to existing literature.•Added more detailed explanation of Fig. 2 and its significance.•Clarified how the electrolyzer load responds to decreases in PV output through real-time controls.•Added more detailed discussion on the experimental results and differences between figures.•Provided details on how the empirical equation for hydrogen production rate was derived from experimental data.•Specified the converter topology, ratings, and control algorithm used.•Discussed mechanical and chemical constraints of the electrolyzer and how they were accounted for.•Explained the dynamic models used - electrical load model of the electrolyzer and relating current to stack power demand.•Showed validation of models by comparing simulation results to hardware measurements.