Hydrogen is a non-toxic and very energetic gas. It is able to produce heat by direct combustion with, as a residue, water, but it can also produce electricity and heat in fuel cells with, once more, as a residue, water. Because of this non-polluting combustion, it is considered one of the potential energy vectors of the future, provided that its production is carbon-free.
Very little existing in the natural state, hydrogen is currently mainly produced from fossil hydrocarbons via mature production processes such as the steam reforming of natural gas or the gasification of coal with the disadvantage of co-producing carbon dioxide. carbon. Environmental constraints are leading to a shift towards electrolysis provided that the electricity used is carbon-free, or towards other processes for producing renewable and green hydrogen from biomass.
The “colors of hydrogen” make it possible to classify hydrogen production techniques according to the origin of the energy used and the quantity of carbon dioxide emitted. Since the entry into force on January 1, 2022 of the European Green Taxonomy, we now speak of “low-carbon” hydrogen.