Hydrogen Production by Means of Small-Scale Multi-Tower CSP Plants Based on sCO2 Power Cycles and Solid Oxide Electrolysers

Concentrated Solar Power can play a relevant role in the decarbonization of the energy sector as it can integrate cost-competitive Thermal Energy Storage, allowing for dispatchable electricity generation. Furthermore, there has been a notable increase in hydrogen demand over the past decade, with most of it being produced using fossil fuels, entailing a large contribution in CO₂ emissions. In this context, the Italian Research Project of National Relevance MUSIC aims to demonstrate the potential of small-scale multi-tower concentrated solar power plants with sodium as heat transfer fluid that are thermally and electrically integrated with a solid oxide electrolyzer to produce green hydrogen and electricity. The objective of this study is to evaluate the performance of a 2 MWel plant for hydrogen production located in Sicily, Italy, by means of numerical models specifically developed to accurately simulate the plant components. A parametric analysis on the number of modules has been carried out and the results show that plants characterized by a smaller field achieve higher optical efficiencies and a lower auxiliary consumption of the HTF pump, at the expenses of lower receiver and piping thermal efficiencies. A maximum yearly solar to hydrogen efficiency of 16.6% was achieved, which largely exceeds the one of conventional PV + PEM systems, proving the potential of the technology.