Production and storage of hydrogen: Present scenario and future perspective

Hydrogen (H-2), an environmentally clean energy-carrier gas, is produced mainly from fossil fuel, biomass and water. H-2 (90%) is produced at high temperature by the reactions of natural gas or light oil fractions with steam, besides coal gasification and electrolysis of water. Among biological production of H-2, direct and indirect biophotolysis, fermentation, photosynthetic production and in vitro enzymatic conversion of biomass are important. H-2 is a substance with high energy content compared to its weight, however, energy content compared to volume is rather low. This poses challenges with respect to storage compared to storage of gasoline, a liquid. Current H-2 storage approaches involve compressed H-2 gas tanks, liquid H-2 tanks, metal hydrides, carbon-based materials/high surface area sorbents, and chemical H-2 storage. This paper reviews various production and storage strategies of H-2.