A Technical, Economic and Environmental Analysis of Combining Geothermal Energy with Carbon Sequestration for Hydrogen Production

Among numerous techniques for the hydrogen production without harmful emissions, especially avoiding the carbon dioxide emissions, hydrogen technologies driven by geothermal energy represent an attractive solution. This paper is interested in the process by which the electricity generated from geothermal power plant that is operated using CO2 as heat transmission fluid is exploited for hydrogen production through water electrolysis. A numerical simulation is used to evaluate the potential for hydrogen production and to estimate the levelized cost of electrolytic hydrogen. We also present brief analysis of environmental issues, including the carbon tax. The results show that the process has a good potential for geothermal hydrogen production, is capable of producing about 22 kg/h of electrolytic hydrogen for the geothermal source of carbon dioxide mass flow rate of 40 kg/s and a temperature of 296 K. In economic regard, the electric energy system costs are the major component of the total hydrogen production cost (more than 90%). The estimated cost of hydrogen is 8.24 $/kg H2. By including the carbon tax, the cost of hydrogen production becomes far more competitive.