The influence of energy storage hydrogen aqua electrolyzer (HAE)-fuel cell (FC) units on automated generation control (AGC) of linked power systems is investigated in this study. In today's fast-paced world, AGC plays a critical role in ensuring that the power supply meets high-quality requirements. This study proposes a novel fuzzy gain scheduling (FGS) PI controller as an intelligent control approach for enhancing AGC power system performance with or without HAE-FC units. The FGS-PI controller's input scaling factors (SFs) and output SFs are tuned using a class topper optimization. The suggested FGS-PI controller's sensitivity analysis is shown to evaluate its performance. Due to changes in system parameters and multi-step load disturbances, the suggested controller performs well.