Safe seasonal energy and hydrogen storage in a 1 : 10 single-household-sized pilot reactor based on the steam-iron process

Our society is gradually moving from traditional energy sources to renewables. Due to the temporal mismatch between the production and demand of renewables, seasonal energy storage is proposed as a way to bridge the gap and ensure reliable power supply throughout the year. In this article, we demonstrate a seasonal energy storage process based on the redox pair iron/iron oxide, where energy is stored in the form of fine iron powder produced on-site by reducing iron oxide with electrolytic hydrogen, and released by oxidizing iron with steam. We prove its feasibility at a technically relevant scale, in a 1 : 10 scaled-down pilot reactor representing the electricity need of a typical European household. The operating data of the reactor, together with physico-chemical analysis of the iron/iron oxide during this process, and calculated estimation of its investment cost, provide a solid foundation for its future application in the field of energy storage.