The promise of hydrogen as an energy carrier that can provide pollution free, carbon-free power and fuels for buildings, industry, and transport makes it a potentially critical player in our energy future. The acceleration of hydrogen technology development is appropriate and necessary. Hydrogen has been suggested as a convenient, clean-burning fuel. Hydrogen gas may be stored as a compressed gas or as a liquid. Hydrogen has good properties as a fuel for internal combustion engines in automobiles. The main disadvantages of using hydrogen as a fuel for automobiles are huge on-board storage tanks, which are required because of hydrogen's extremely low density.