To circumvent equipment damage, load shedding and possible blackouts in electric power system, brisk acting energy storage units can excellently shrink the frequency and tie-line power oscillations generated due to small load perturbations. This paper investigates the impact of the energy storage hydrogen aqua electrolyzer (HAE)-fuel cell (FC) units on automatic generation control (AGC) of interconnected power systems. AGC plays the pivotal role in providing the electricity supply with good quality standards in the fast growing word of todays. For this, AGC entails highly proficient and intelligent control technique. Hence, a new fuzzy tilt integral derivative with filter plus double integral (FTIDF-II) controller is proposed for the first time in AGC field as an intelligent control technique to upgrade AGC performance of power systems with/without HAE-FC units. A recently appeared socio-politically influenced global search metaheuristic imperialist competitive algorithm (ICA) is used to tune the parameters of FTIDF-II controller. In FTIDF-II controller, asymmetrically membership functions (MFs) are employed, where MFs alongside zero provide fine-tuning and away from zero coarse-tuning. The efficacy of the control approach is critically analyzed on three 2-area power system models selected from the literature. The supremacy of FTIDF-II controller is established over FTIDF and existing PID/PIDF/TIDF/FPI/FPID/FPIDF/FPIDF-II structured controller optimized via various newly emerged optimization techniques. Investigation affirms that the dynamic performance of the systems with FTIDF-II controller improves further in the presence of HAE-FC units. Sensitivity analysis demonstrated that the proposed controller is robust and executes competently at variations in the system parameters and random load perturbations. (C) 2019 Elsevier Ltd. All rights reserved.