Techno-economic Assessment and Optimization of a Solar-Driven Power and Hydrogen Co-generation Plant Retrofitted with Enhanced Energy Storage

Pioneering solar-driven power and co-generation facilities stands as a crucial stride toward decarbonizing energy systems. Moreover, the production of green hydrogen serves as the cornerstone of decarbonized energy systems. This study evaluates a solar-driven co-generation plant for power and hydrogen production employing the vanadium-chlorine cycle. The plant is integrated with a thermal storage system of solid materials as a packed bed to increase the capacity factor. Three cases are studied based on energy storage materials. The first case uses alumina, while the second and third cases utilize steel slag with varying compounds. Following an extensive sensitivity analysis, an artificial neural network is formulated to subject each case to three-objective optimization using a genetic algorithm. Moreover, Seville in Spain is selected as the designated case study, and real-world solar availability data is employed to enhance the authenticity and realism of the results. Results show using steel slag as an energy storage material instead of alumina reduces the levelized cost of energy and the cost of thermal energy storage units by 14 and 69%, respectively. From both economic and environmental perspectives, the second case emerges as the most favorable option. Through the implementation of a 36.3-hectare solar farm in Seville, the second case generates 38.5 GWh electricity and 2.1 kton hydrogen with a cost of 189 USD/MWh and 7.2 USD/kg, respectively, factoring in expenses for hydrogen compression and storage facilities. This case has the potential to reduce Spain's CO2 emissions by 51 kton per year.