Abstract
Abstract This study evaluates the performance of a copper–chlorine (Cu–Cl) thermochemical cycle integrated with concentrated solar power for sustainable hydrogen production operating below 550°C. A pilot-scale Cu–Cl system comprising three reaction steps was coupled with a linear Fresnel solar collector providing thermal energy at 520°C and tested over a 6-month period at an Arizona test facility. The integrated system achieved an average solar-to-hydrogen efficiency of 18.7% and a daily production rate of 24.3 kg/100 m2 collector area. Operational stability was evidenced by a cycle closing ratio of 98.3% and effective material durability, despite a 15.5% reduction in catalyst activity over 600 h. Life cycle assessment indicates a global warming potential of 1.64 kg CO₂-eq/kg H₂, representing an 85% reduction relative to steam methane reforming. Techno-economic projections estimate commercial-scale production costs at $3.86/kg H₂. These results validate the technical feasibility of the solar-driven Cu–Cl cycle for large-scale, zero-emission fuel generation.