There are various ways implemented to produce hydrogen, most of which are in the early stages of development. Synthesis gas is created by reacting natural gas with high temperature steam or by partial oxidation. Hydrogen is produced when such gas reacts with water. An electric current generated by renewable energy technologies splits water into hydrogen and oxygen. Coal or biomass is converted into gaseous components and then into synthesis gas. Reaction with steam produces hydrogen. Other ways include renewable liquid reforming, nuclear high-temperature electrolysis, high-temperature thermo-chemical water-splitting as well as photo-biological and photo-electrochemical means,

The cost of production technologies remain the primary challenge for hydrogen production. The reduction of cost and environmental impacts is the main concern of many government and industry research and development projects.