Building on the results of FP5 project HYDROSOL, HYDROSOL II concerns the technical realisation and evaluation of a directly solar heated process for two-step thermo-chemical water splitting using an innovative solar thermochemical reactor as the core of a volumetric receiver. The reactor is based on ceramic honeycombs incorporating active metal oxide redox pair systems. This method provides two major advantages: Hence no transportation/recycling of vast amounts of solid materials is needed and Hydrogen product separation is straightforward.

As a central result of HYDROSOL, the feasibility of solar hydrogen production and the capability formulti-cycling of the thermo-chemical process developed was applied and proven. The results of the experimental and conceptual investigation show that a scale-up is possible and worthwhile and that the technology applied is a promising method for mass production of “renewable” hydrogen. Cost analyses indicate that technical improvements of the HYDROSOL process provide the potential toreduce by the production costs of hydrogen from 18 to 10-12 Eurocent/kWh (LHV) in the mediumtermand by ongoing commercialisation to 6 Eurocent/kWh (LHV) in the long-term.

In HYDROSOL II, a pilot reactor for solar thermo-chemical hydrogen production is being designed, constructed, installed and operated. The tasks of the Project include the enhancement oflong-term stability of the thermochemical reactor, the development of operation/control strategy for continuous production of hydrogen, the design and development of a 100 kWth pilot reactor, the installation and test operation of the pilot reactor and all necessary peripheral components at a solar platform. Finally a detailed technical and economic evaluation of the entire process and its integrationin future solar power plants will be performed.