Design and optimization of a combined solar thermophotovoltaic power generation and solid oxide electrolyser for hydrogen production

Highlights: • A combined solar thermophotovoltaic power generation system is proposed. • High-temperature solid oxide electrolyzer is used for hydrogen production. • Solar to electrical efficiency of the scaled-up STPV device is 17%. • Total efficiency of the integrated system is 34%. - Abstract: This study proposes a novel integrated solar-TPV device with a solid oxide electrolyzer cell to utilize the solar energy for hydrogen production. It explores the possibility of employing a high temperature solar-thermal-photovoltaic power generation technology as a power source for a steam electrolyzer as a high-efficiency and applicable hydrogen production method. Mathematical and electrochemical modeling of the subsystems is conducted and performance of the system in different operating conditions such as current density, temperature, and steam mole fraction of SOEC is analyzed. An STPV device of multiwalled carbon nanotube (MW-CNT) absorber and 1D Si/SiO₂ PhC emitter and InGaAsSb PV cell is employed to maximize the solar energy utilization. A detailed system level model in this part is conducted and the solar to electrical efficiency of the scaled-up STPV device reached to 17%. The results show that this STPV device can provide the power demand in SOEC system. A planar cathode-supported high-temperature electrolyzer cell was designed to perform in an exothermic mode and the result was validated by the experimental data precisely. The sensitivity analysis showed that 7458 kg/h hydrogen can be produced in the proposed system with 54% electrical for SOEC efficiency. The major implementation challenges are presented to provide a comprehensive insight into performance, potential development, limitations and challenges of the integrated system. The proposed combined system shows the overall efficiency can reach to 34%. This high efficiency makes this novel hybrid system a competitive option in solar-based hydrogen production technologies.