Renewable-energy storage via micro-burner coupled iron–oxygen looping: Thermodynamic and thermo-economic analysis

With the rapid expansion of renewable energy scale worldwide, energy transportation technologies have developed swiftly, and the application of energy carriers such as hydrogen and iron has attracted extensive attention. To elevate iron's role as a long-duration, carbon-free energy vector, we propose two fuel-splitting power cycles that integrate micro-scale burners into a trans-continental metal-fuel storage chain. In both layouts, hydrogen or iron is separately oxidized in micro-burners to supply the high-temperature heat required for the endothermic reduction reactor. A comprehensive 5E analysis—covering energy, exergy, environment, economy, and exergoeconomics—was conducted to evaluate and compare the thermodynamic and economic performance of the two systems. Results show that the Fe-splitting system achieves 0.94% higher energy efficiency and 2.32% higher energy storage efficiency than the H 2 -splitting system, with exergy efficiencies of 53.36% and 52.80%, respectively. Life cycle assessment indicates negligible environmental impacts during system operation for both configurations. Economic evaluation further reveals that the levelized cost of electricity of the Fe-splitting system is 64.61 $/MWh, which is 3.35 $/MWh lower than that of the H 2 -splitting system. Exergoeconomic analysis highlights that the photovoltaic, reduction chamber, and alkaline electrolyzer subsystems account for up to 90.55% of total exergoeconomic destruction, suggesting that improvements in these components are crucial for system optimization. Additionally, the reliability of the model was verified through sensitivity analysis of multiple factors. Overall, the introduction of micro-burners effectively enhances the thermodynamic performance of long-duration metal-based energy storage systems. It provides a framework and direction for the advancement of metal fuel storage technologies and propels the advancement of long-distance storage and transportation technologies for renewable energy. • Micro-burner integrated iron–oxygen looping for high-efficiency energy storage. • Fe-splitting system achieves 46.45% energy efficiency and 53.36% exergy efficiency. • The incorporation of a micro-burner enhances the energy storage efficiency to 55.19%. • The Fe-splitting system costs 3.35 $/MWh less than the H 2 -splitting system.