Electrolysis is a method that uses water (H2O) as a raw material for producing hydrogen and oxygen gas using an electric current.
Discovered in the late 18th century, this method was industrialized for the first time in 1900. In 1939 the first electrolyzers generating 10 000 Nm3/h of hydrogen were installed; this capacity is still used in the largest production facilities in the world today.
However, water electrolysis is still little-used today. Only 5% of the hydrogen produced throughout the world comes from this process. The other 95% of hydrogen is produced by converting natural gas.
Whatever the source of electricity being used for electrolysis, the hydrogen carbon footprint remains more or less high. Thus, with an electric current from renewable energy (solar, wind, hydro, biomass, etc.), green hydrogen (with a very low carbon footprint) is produced.
Water electrolysis, in combination with renewable energy, is therefore a very relevant solution for:
There are different electrolyzer technologies:
However, currently only alkaline electrolysis technology is sufficiently developed and offers economic competitiveness as compared to traditional hydrogen production technologies with a deplorable carbon footprint!
The emergence of renewable energies should encourage the production of green hydrogen and enable input for future markets, which is key for the environment: notably green mobility (hydrogen-powered vehicles) and renewable energy storage at competitive prices.