Driven by Europe as part of the Green Deal, the development of the green hydrogen sector is in the starting blocks in Europe and Wallonia. Hydrogen is indeed essential to the success of the energy transition, particularly for industries that are difficult to electrify and already use H₂, heavy and resource-intensive industries that emit large quantities of CO₂, and heavy-duty transport. The hydrogen value chain rests on three pillars :  production / transport and storage / uses.