In its desire to reduce its greenhouse gas emissions by 50%, Switzerland wishes to progressively develop the use of low-carbon energy carriers in addition to reducing consumption. The short-term possibilities for industrials using grey hydrogen consist in replacing this use by renewable hydrogen which is what Zwahlen & Mayr SA wants for its processes. The PRHYSM project aims to produce renewable hydrogen where it is consumed by Zwahlen & Mayr SA, from solar electricity via high-temperature electrolysis of water, replacing grey hydrogen imported by truck. At the end of this project, SolydEra will be able to install its electrolyser in Switzerland, as well as internationally, and to know its performance in industrial operating conditions. Romande Energie SA will be able to offer a new, virtuous H2 contracting service to all Swiss industrialists.