In this paper, we conduct a comparative performance assessment study between electrolyzer and steam methane reformer (SMR) to investigate which one is a better option from energy, exergy and sustainable perspectives. The power to both systems is provided by a quintuple flash power plant running on a geothermal source. The quintuple flash power plant is selected as a power source due to its capability of producing power in an efficient and environmentally benign manner. The results show that increasing ambient temperature increases the overall system exergy efficiency of the first system (consisting of an electrolyzer) from 51.7% to 60.8% while this remains almost constant by 6.8% for the second system (containing SMR). The amount of hydrogen produced by electrolyzer and SMR vary from 3.9 L/s to 65.3 L/s and 365 L/s to 426.5 L/s, respectively with rise in the geothermal source temperature. With increase in geothermal source temperature, the exergy efficiencies change from 54.2% to 62.1% for the first system and 6.6% to 7.6% for the second system. Furthermore, the first system is much more sustainable as compared to second system.