Solar hydrogen production: Techno-economic analysis of a parabolic dish-supported high-temperature electrolysis system

The roadmap for the hydrogen uptake passes through the development of near-zero emission and/or renewable technologies for hydrogen production. This is the rationale for the investigation of renewable power-to-fuel, namely the coupling between high temperature electrolysis and concentrating solar power. The proposed plant is conceived to supply hydrogen for a small refuelling station. It is based on solid oxide electrolyser cell technology, which performs water electrochemical reduction, in order to produce a target of 150 kg d(-1) of hydrogen. The plant is integrated with a parabolic dish solar field designed to provide both electricity and thermal energy, necessary for the electrolysis reaction to take place. Specifically, a modular multi-dish configuration is selected, in which electric power is produced by 30 kWel solarized micro-gas turbines placed in the dishes' focus. In addition to considering a pure renewable power input, a hybridization with natural gas is considered to face the variability of solar resource. Once a yearly H-2 yield is estimated, a preliminary economic analysis is carried out and the levelised cost of hydrogen is subsequently obtained. It is found that the system can be operated at a nominal solar-to-hydrogen efficiency above 30%, with a solid oxide electrolysis cell efficiency around 80%. In hybrid conditions, 10 parabolic dishes (9 generating electricity through the micro-gas turbines, 1 supplying heat to the solid oxide electrolysis cell) are needed to produce the target 150 kg d(-1) of hydrogen. In conclusion, the competitiveness of the plant is evaluated in comparison with other solar fuels technologies.