Techno-Economic Comparison of Particle and Gas-Based Central Solar Thermal Receiver Systems for the Cogeneration of Electricity and Hydrogen

Abstract The cogeneration of hydrogen and electricity can potentially increase the economic attractiveness of concentrated solar thermal power. In this article, a techno-economic analysis is conducted to evaluate the feasibility of a concentrated solar plant coupled to a supercritical carbon dioxide (sCO2) Brayton cycle, a four-step copper–chlorine (Cu–Cl) thermochemical hydrogen production cycle, and a thermal energy storage system. Thermal energy storage can increase the capacity of the power cycle and hydrogen plant. Two cases are considered. In the first case, a solid particle receiver is used to provide thermal input to the overall system and serves as the thermal storage system via hot particles. In the second case, a high-efficiency, micro-pin central receiver using sCO2 is considered. The receiver produces sCO2 at temperatures greater than 720 °C operating in a closed loop, which provides energy to molten salt thermal storage, the power cycle, and the hydrogen production plant. Simulation models of the receiver heat transfer loop, thermal storage system, power cycle, and hydrogen plant are developed and used to size key components including heat exchangers, reactors, and turbomachinery. These simulations are then utilized to estimate thermodynamic parameters, conduct economic analyses, and evaluate the system performance, as well as determine the costs associated with the cogeneration of hydrogen and electricity. Results indicate that the particle-based system achieves a levelized cost of electricity (LCOE) of $0.060 kWh ± $0.0036 kWh and a levelized cost of hydrogen (LCOH2) of $3.79 kg ± $0.376 kg, with energy and exergy efficiencies of 17% and 18%, respectively. The gas-based system demonstrates higher efficiencies (19% energy and 21% exergy) but has greater costs, with an LCOE of $0.106 kWh ± $0.0064 kWh and an LCOH2 of $4.167 kg ± $0.463 kg.