Energy and economic assessment of an industrial plant for the hydrogen production by water-splitting through the sulfur-iodine thermochemical cycle powered by concentrated solar energy

The faster and faster global growth of energy consumption generates serious problems on its supply and about the pollution that may result. Through the use of thermochemical cycles it is possible to use renewable energy to produce hydrogen from water, with the dual purpose of having an unlimited source of energy without producing greenhouse gases. This paper provides an energy assessment and a preliminary design of an industrial plant for the production of 100 tons/day of hydrogen by sulfur-iodine thermochemical cycle. Afterwards, an economic analysis is performed to assess the hydrogen production cost, with the assumption to power the process by solar energy. For this purpose, a double solar facility is sized: a parabolic trough plant, for the mean temperature duties, and a central receiver tower one for the higher temperature duties. The efficiency of the thermochemical cycle by itself is about 34%. If this value is associated with the electrical energy production, including the efficiency of the solar plants, the total heat-to-hydrogen efficiency of 21% is obtained, with a hydrogen production cost of about 8.3 €/kg. ► Hydrogen production by water through SI thermochemical cycle using solar energy. ► Accurate energy analysis to optimize the thermal efficiency of the plant. ► Sizing of the plant equipments. ► Choice and sizing of the concentrated solar plant. ► Economic analysis to foresee the hydrogen production cost by this technique.