Investigating the Potential of Concentrated Solar Thermal Power for Co Generation of Electricity and Hydrogen

Abstract

Hydrogen has recently gained significant attention as a potential energy carrier to support decarbonization across multiple sectors. However, current hydrogen production technologies primarily rely on non-renewable sources and contribute substantially to greenhouse gas emissions. Solar-driven hydrogen production offers a pathway toward low-carbon energy systems, but challenges remain in achieving high efficiency, reducing costs, and identifying suitable deployment regions. This dissertation investigates the technical and economic feasibility of solar-based hydrogen production systems through the integration of high-temperature concentrated solar power (CSP) technologies, advanced power cycles, thermochemical hydrogen production, and photovoltaic-electrolysis pathways. The research first evaluates the feasibility of cogenerating electricity and hydrogen using a high-temperature central receiver system coupled with a supercritical carbon dioxide (sCO₂) Brayton cycle and several hydrogen production pathways. Thermodynamic simulations were used to assess the performance of the four-step copper-chlorine (Cu-Cl) thermochemical cycle, the hybrid sulfur cycle, alkaline electrolysis, and polymer electrolyte membrane (PEM) electrolysis. Results indicate that the Cu-Cl thermochemical cycle provides the highest solar-to-hydrogen efficiency when integrated with high-temperature CSP systems. Building on this foundation, a detailed thermo-economic analysis was developed for an integrated CSP-sCO₂-Cu-Cl cogeneration system incorporating thermal energy storage. Two receiver technologies were evaluated as high-temperature heat sources: a falling-particle receiver and a high-efficiency micro-pin gas receiver. Component-level models of the receiver heat-transfer loop, thermal storage system, power cycle, and hydrogen plant were used to size key equipment and estimate system performance and costs. Results show that the particle-based system achieves lower hydrogen and electricity costs compared with the gas-based configuration, despite slightly lower thermodynamic efficiency. To further evaluate solar hydrogen pathways, A multi objective optimization framework was then developed to compare CSP-based cogeneration systems with a photovoltaic-battery-PEM electrolyzer system. Using the Non-Dominated Sorting Genetic Algorithm II (NSGA-II), system designs were optimized to minimize the levelized cost of electricity (LCOE) and hydrogen (LCOH₂) while maximizing efficiency. Cost uncertainty was incorporated using Latin Hypercube Sampling with AACE Class-5 uncertainty ranges. Results show that optimized CSP-based systems can achieve lower hydrogen costs and higher solar-to useful-energy efficiencies than PV-PEM systems under similar techno-economic assumptions. Finally, the optimized systems were evaluated across multiple candidate locations within the U.S. Department of Energy (DOE) Regional Clean Hydrogen Hubs to assess regional deployment potential. Site-specific solar resources, land availability, water costs, and proximity to pipeline infrastructure were incorporated using geographic screening methods. The results show that high-DNI regions in the southwestern United States offer the lowest hydrogen costs for CSP-based systems, while PV-PEM systems provide broader geographic applicability but generally higher production costs. Infrastructure accessibility, particularly proximity to pipeline networks, was found to significantly influence delivered hydrogen cost. Overall, this dissertation provides an integrated thermodynamic, techno-economic, and regional assessment of solar hydrogen production pathways. The results identify key system design parameters and location-specific factors that influence hydrogen cost and efficiency, providing a framework for evaluating and deploying large-scale solar hydrogen systems.