This study reports on the feasibility of applying polymer electrolyte membrane fuel cells (PEMFCs) system to an energy storage system (ESS). We modeled each constituting system to compute the overall efficiency of the ESS. As a result, it was verified that the power plants’ electric powering capability can be curtailed. The amount of reduction is equal to that of 2nd Gori Nuclear Power Plant currently under construction. We calculated that approximately 320.85 L/day · MW of hydrogen is produced on a national scale. Also, Seoul’s demand output power of PEMFC and the requisite area of sites to install the PEMFC system are approximately 236 MW and 59059 m² respectively. This study can contribute to preventing the upsurge of the entire electric powering installed capability. Based on the present technology level, this study diagnoses the use of hydrogen-based ESS which will be introduced in the upcoming hydrogen economy period. Considering the water electrolysis by polymer electrolyte membrane water electrolyzers are currently at the beginning of commercialization and the energy density per mass of hydrogen is exceedingly high, we anticipate that the future of hydrogen base ESS’ effectiveness will reach greater levels than the analysis of this study.