4. Comparative Performance Assessment of Two Geothermal-Based Integrated Systems for Hydrogen Production

In this paper, we conduct a comparative performance assessment study between a conventional electrolyzer and a steam methane reformer (SMR) to investigate which one provides a better option from energy, exergy and sustainability 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 due to its capability of producing power in an efficient and environmentally-benign manner. The results show that increasing the 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 at 6.8 % for the second system (containing SMR). The amount of hydrogen produced by the electrolyzer and SMR vary varies from 3.9 to 65.3 L/s and 365 to 426.5 L/s, respectively, with a rise in the geothermal source temperature. With increase in the geothermal source temperature, the exergy efficiencies vary 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 compared to the second system.