Its production [ Return towards Hydrogen ]
Abundantly present in the sun, gaseous hydrogen is almost entirely absent from our atmosphere. So it must be extracted from the molecules that contain it. Two main approaches are now used industrially.
In the “hydrocarbon” approach, hydrogen is extracted from hydrocarbons mainly composed of hydrogen and carbon, such as natural gas, coal and petroleum products. These hydrocarbons, oxidized by steam or oxygen, result in hydrogen (H2) and carbon dioxide (CO2).
The quantity of CO2 emitted depends on the original source. Producing hydrogen from coal emits a lot more CO2 than using natural gas. That is why 95% of all hydrogen is now produced from methane (CH4), the main component of natural gas.
In the “electrolytic” approach, an electric current is used to “break” the water molecule and produce hydrogen and oxygen: this is electrolysis. The electricity can come from different sources and especially from renewable sources: photovoltaics, wind, etc. In this case, the production of hydrogen does not emit any CO2.
Other studies are being conducted in laboratories today: microscopic alga that use the sun’s energy to transform water, high-temperature electrolysis, the decomposition of water by means of a thermochemical cycle…
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