Geothermal energy use in hydrogen production: A review

The major logics resulting in hydrogen production can be mentioned as fossil fuel depletion and climate change. In this way, hydrogen is produced with the help of numerous processes based on traditional and alternative energy resources like coal, natural gas, wind, solar, biomass, and geothermal energy. Over the past decade, the attention of research institutions and industry has been drawn to hydrogen, inspired by developments in renewable energies. Hydrogen production can be considered as an exceptional choice to make complete utilization of the renewable energy. Among diverse technologies, hydrogen production based on geothermal energy offers great promise. In this paper, initially a concise summary of present and advancing hydrogen production technologies is presented, and secondarily a comprehensive review of research associated with hydrogen production based on geothermal energy is provided. Thirdly, the process descriptions of geothermal-assisted hydrogen production coupled with its technical, economic, and environmental aspects are addressed. Finally, comparative assessments of costs and environmental aspects related to hydrogen production based on different energy sources have been performed. In accordance with the results, the geothermal-assisted hydrogen production cost based on electrolysis is competitively lower than other sources like wind, solar thermal coupled with natural gas, solar PV, and grid. Also, the same behavior can be seen for geothermal-assisted hydrogen production cost based on thermochemical process.