Capitalizing on the predecessor Projects HYDROSOL and HYDROSOL-II that have introduced the concept of multi-channeled honeycomb monolithic solar reactors for hydrogen generation from water splitting via redox-pair-based thermochemical cycles, HYDROSOL-3D focused on the next step towards commercialisation and involved all activities necessary to prepare the erection of a HYDROSOL-technology-based 1 MW solar demonstration plant. In this respect HYDROSOL-3D was concerned with the complete pre-design and design of the whole plant including the solar hydrogen reactor and all necessary upstream and downstream units needed to feed in the reactants and separate the products and the calculation of the necessary plant erection and hydrogen supply costs.

This design started with the fine-tuning of the materials’ composition and the reactor configurations advanced through the Projects HYDROSOL and HYDROSOL-II in order to ensure long-term, reliable solar-aided hydrogen production at industrially attractive yields. Designs and concepts that will enhance incorporation of redox material in the reactor and reduction of radiation losses were considered and implemented. In parallel, the control concepts, algorithms and procedures necessary for the operation of such a plant were developed and integrated in a process simulation software. The pre-design components and the control strategies were thoroughly validated by experiments spanning the whole reactors’ range: from small lab-scale reactors to pilot reactors coupled with solar tower facilities, in order to fully verify their transferability to large-scale operation. Two alternative plant scenario options were analyzed: i) adaptation of the hydrogen production plant to an existing solar field/tower facility and ii) development of a new completely optimized hydrogen production/solar plant “from scratch”. The most promising option was selected and analyzed in detail, the complete plant layout was delivered, all necessary components were defined and sized, the control system was finalized and the operation of the whole plant was simulated. Finally, a techno-economic and market analysis determined the feasibility of the process scale-up to the MW scale, by calculating the cost necessary to erect a 1 MW_th demonstration plant and the hydrogen production and supply costs for the case of an industrial scale plant of 21 MW_th. Elaborated realistic scenarios for market penetration and on potential synergies with other technologies complemented the Project.