The application of fuel cells in our future energy system depends on a cost-efficient production and supply of hydrogen (H-2) and carbon monoxide (CO). The process cycle iron oxide/iron/hydrogen offers a simple possibility to store the energy of synthesis gases in the form of sponge iron and at the same time to reform and condition these synthesis gases. As ＇product＇ of this energy storage system one receives pure hydrogen. The ＇Sponge Iron Reaction＇ (SIR) process offers some advantages against conventional gas cleaning and conversion processes: (i) low-cost hydrogen by using cheap sponge iron materials; (ii) high-quality hydrogen from low-BTU gases by a two-step operation; (iii) high efficiency compared with competitive technologies and (iv) system versatility and ease of siting. Commercially available iron ore pellets (hematite Fe2O3) and self-produced pellets are used as contact mass.