How is hydrogen produced?

Hydrogen is not a source of energy; it is an energy carrier. Before it can be used, it must be separated from the molecules containing it. Hydrogen can be produced from water, from hydrocarbons such as coal, crude oil and natural gas, and from biomass.

Current Methods

• Steam reforming of natural gas: Natural gas is reacted with steam to initially form hydrogen and carbon monoxide. Further reaction forms more hydrogen and carbon dioxide. Currently, steam reforming of natural gas is the most common method of producing hydrogen; however, it does result in greenhouse gas (GHG) emissions.
• Electrolysis of water: An electric current is passed between two electrodes submerged in water. Hydrogen accumulates at the cathode and oxygen at the anode. This method of producing hydrogen results in no GHG emissions. However, if the electricity used was generated by coal-, oil-, or gas-fired thermal processes, some GHG emissions are associated with the hydrogen production life cycle. If the electricity used was generated by hydro, nuclear, solar or wind power, no GHGs are produced or emitted.
• Waste stream hydrogen: Hydrogen is a byproduct of some industrial processes such as the manufacture of sodium chlorate via electrolysis of sodium chloride brine.

Methods under development

• Hydrogen from coal: Coal is first gasified by exposure to oxygen under high pressure. The resulting synthesis gas is then steam reformed in a process similar to steam reforming of natural gas.
• Hydrogen from biomass: Hydrogen is produced from biomass in a process similar to that used for coal. Biomass is both renewable and carbon neutral.
• Biological water splitting: Photosynthetic microbes create hydrogen from water as part of their normal metabolic processes.
• Photoeletrochemical water splitting: Specialized photovoltaic cells convert sunlight to electricity in sufficient amounts to electrolyse water into hydrogen and oxygen.
• Solar thermal splitting: Concentrated sunlight is used to generate temperatures high enough to split methane into hydrogen and carbon.

Hydrogen can be produced locally, at large central plants or in small distributed units located at or near the point of use. This means that every community, even remote areas, can become an energy producer.

When produced using renewable energy sources and powering highly efficient fuel cells, the environmental benefits of hydrogen are even greater. Plus, hydrogen can be produced and stored using off-peak energy produced by renewable energy technologies such as solar, wind and tidal generation.

When used with energy efficient fuel cells, hydrogen will play an important role in extending our current energy supplies as we move forward to a clean energy future.