On earth, hydrogen usually occurs in bound form, e.g. in water (H2O) or in hydrocarbons such as methane, petrol and other organic compounds.
Hydrogen gas (H2) can be produced by electrolysis of water, among other things. The electrolysis supplies electrical energy and thus forces a chemical reaction – here separation of the water molecule into H2 and oxygen O2:
2 H2O + electrical energy ⇌ 2 H2 + O2
H2 can be stored like natural gas. Since the reaction is reversible, the H2 can later react with O2 from the air to produce electricity. Through the production and consumption of H2, it is therefore possible to store electricity in large quantities. If, in the future, electricity is to be produced mainly by wind energy and photovoltaics, we need such storage facilities for times when neither the wind is blowing nor the sun is shining.
H2 can also power electric vehicles. Instead of a battery, a fuel cell supplies the electricity for the electric motor. If the range is to be increased, only the tank needs to be enlarged, not the entire battery. Another important application of H2 is in industry. For example, it is being tested whether H2 can replace coke in steel production, which would significantly reduce CO2 emissions in this sector. In the Green FabLab, the production of H2 by electrolysis, its storage in gas tanks and its application for power generation in the fuel cell is demonstrated.