Solar hydrogen production using two-step thermochemical cycles

In this paper, a thermodynamic study is presented on solar hydrogen production using concentrated solar energy and two-step thermochemical cycles. After discussing the temperature availability from solar installations and temperature requirements, two-step water decomposition processes using metal/metal oxide cycles are studied in detail. Some hybrid metal/metal oxide, purely thermochemical and hybrid, metal oxide/metal sulfate cycles are also discussed. The solar high temperature heat source is briefly analyzed and interfacing problems are discussed.