Thermodynamic analysis of geothermally driven high-temperature steam electrolysis system for hydrogen production

Abstract

Hydrogen production by high-temperature steam electrolysis (HTSE) has been receiving increasing attention worldwide due to its high efficiency and carbon-free operation. Although it is still considered in its early developmental stage, it offers a promising solution for highly efficient hydrogen production. From the thermodynamic viewpoint of water decomposition, it is more advantageous to electrolyse water at high temperatures because the energy is supplied in mixed form of electricity and heat. In this study, a HTSE process coupled with and powered by a geothermal power plant is considered for analysis and assessment and as a case study. In this regard, its thermodynamic analysis through energy and exergy is conducted for performance evaluation and comparison purposes. As a result, compared to conventional water electrolysis, the operation at high temperatures reduces the electrical energy requirement for the electrolysis and also increases the efficiency.