We talk of green hydrogen when the method used to produce it is based on renewable energy sources.
Green hydrogen, grey hydrogen : what’s the difference?
Hydrogen is not a primary energy source like oil or coal. Before it can be used, it has to be produced using an energy source. It is that energy source that determines whether it is “green” or “grey” hydrogen..
Actually, green hydrogen production is different, being based on decarbonised energy sources: renewable electricity from wind or solar. To produce green hydrogen, a water electrolysis process is thus used, which produces no greenhouse gases. It consists in breaking down the water molecules into dioxygen and dihydrogen using an electric current. The electricity used must be from renewables.
Grey hydrogen, meanwhile, is produced using energy from fossil fuels: coal, natural gas etc.
These days, the public authorities are increasingly encouraging the development of green hydrogen. Besides, France has set itself the target of becoming one of the leaders in this field.
Green hydrogen: lever for the energy transition
Green hydrogen production creates a virtuous circle. The use of electricity from wind turbines or photovoltaic cells as part of the water electrolysis process effectively allows storage of that electricity, which is dependent on uncontrollable natural elements (wind and sunlight). On the one hand, energy wastage is avoided, and on the other hand, the stored energy can then be fetched back when needed, particularly during peaks in consumption. Through the use of fuel cells, hydrogen can create electricity without emitting any greenhouse gas.
Green hydrogen helps reduce dependence on fossil fuels and allows energy to be produced more locally. It offers promising prospects for decarbonising mobility and industry.
Green hydrogen is therefore a clean energy carrier that allows diversification of the energy mix and helps the energy transition.