Figure 1.

Hydrogen resources, production techniques, and applications

The six major hydrogen sources, i.e., solar energy, natural gas, biomass, nuclear, wind, and geothermal energies (A). Source-dependent hydrogen production technologies: thermo-chemical water splitting for solar irradiation as the source, steam reforming for natural gas, gasification for biomass, and electrolysis for nuclear, wind, and geothermal energies (B). Gasification schematic adapted with permission from (De Lasa et al., 2011). The most prominent applications of hydrogen fuel include propulsion for automotive, ship and spacecraft, hydrogen power plants, and medical industry (C).