This study presents a parametric study on the performance aspects, through exergy analysis, of the multistage hydrogen gas storage subsystem in a hydropower-based-hydrogen gas fueling station producing 3 kg of hydrogen per hour and storing it. In order to perform an exergy analysis, the following parameters are taken into consideration: (i) mass flow rate of hydrogen (3 kg/h), (ii) inlet pressure of hydrogen (ranging from 1 to 200 bar), (iii) hydrogen storage pressure (ranging from 200 to 900 bar), (iv) dead state temperature (at 25 degrees C), (v) efficiency of electrical motor (90%), (vi) mechanical efficiency (95%), and (vii) polytropic efficiency (90%). It is obtained that increasing inlet pressure of hydrogen gas decreases the energy consumption for compression and storage process while increasing exergy efficiency. Moreover, it is noticed that increasing storage pressure increases the exergy content of hydrogen gas. Copyright (C) 2011, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.