depicted as a virtue (for instance by Hydrogen Europe , various political parties , or industry associations ). While “technology openness” is without doubt a useful concept, in the hydrogen context it is [...] areas, this uncertainty is bounded by the simple laws of physics. Figure 1, adopted from the International Renewable Energy Agency (IRENA), illustrates which applications should be decarbonised with hydrogen [...] direct electrification will be the better choice. For applications such as steel production, international shipping or chemical production, hydrogen will likely establish itself as a key technology. Figure