Geothermal-based hydrogen production using thermochemical and hybrid cycles: A review and analysis

Abstract

Geothermal-based hydrogen production, which basically uses geothermal energy for hydrogen production, appears to be an environmentally conscious and sustainable option for the countries with abundant geothermal energy resources. In this study, four potential methods are identified and proposed for geothermal-based hydrogen production, namely: (i) direct production of hydrogen from the geothermal steam, (ii) through conventional water electrolysis using the electricity generated through geothermal power plant, (iii) by using both geothermal heat and electricity for high temperature steam electrolysis and/or hybrid processes, and (iv) by using the heat available from geothermal resource in thermochemical processes. Nowadays, most researches are focused on high-temperature electrolysis and thermochemical processes. Here we essentially discuss some potential low-temperature thermochemical and hybrid cycles for geothermal-based hydrogen production, due to their wider practicality, and examine them as a sustainable option for hydrogen production using geothermal heat. We also assess their thermodynamic performance through energy and exergy efficiencies. The results show that these cycles have good potential and attractive overall system efficiencies over 50% based on a complete reaction approach. The copper-chlorine cycle is identified as a highly promising cycle for geothermal-hydrogen production.

Potential thermochemical and hybrid cycles for nuclear-based hydrogen production

“…In this paper, the main focus is given to the potential thermochemical cycles for nuclear-based hydrogen production as summarized below [27][28][29][30].…”

“…Development of the lowtemperature Cu-Cl cycle was proposed during this early research period. Although numerous studies have been conducted on Cu-Cl thermochemical cycle, only a few recent ones are given in References [27][28][29][30]34,38]. Some landmark type studies on energy, exergy, and cost analyses of Cu-Cl thermochemical cycle driven by nuclear process heat were performed by Orhan et al [27][28][29].…”

Renewable Energy Scenarios as a Key for Sustainable Rural Area Applications in Turkey

“…Another inspiring example is the coaction between France and Iceland for considering the possibilities of generating hydrogen with high temperature steam electrolysis (HTSE), a process which needs 18% less energy input compared to conventional electrolysis, paired with a geothermal reservoir. The final aim of this project is to generate hydrogen by HTSE paired with a geothermal reservoir in the Icelandic context where superheated water could be supplied at 200°C from geothermal sources [44]. To envisage the production potential, Arnason and Sigfusson reported that the Bjarnarflag geothermal field in Northern Iceland, is able to furnish approximately 50 tonnes of H 2 annually [45].…”

Synthesis of palladium–carbon nanotube–metal organic framework composite and its application as electrocatalyst for hydrogen production

“…Several ways such as hydrolysis [3], thermal catalysis and thermochemical [4,5], photocatalysis [6,7], photoelectrocatalysis [8], steam reforming [9], gasification [10] Electronic supplementary material The online version of this article (doi:10.1007/s40097-016-0203-4) contains supplementary material, which is available to authorized users. and electrolysis [5,11] are used to produce hydrogen.…”

“…and electrolysis [5,11] are used to produce hydrogen. Although in the electrochemical studies platinum (Pt) is known as an excellent electrode for hydrogen generation, but because of limitation of its resource and its expensive price we should look for a suitable alternative to Pt [12].…”