A multidisciplinary consortium gathers NESTE (a Green Refiner as end-user), ENGIE (a global energy system integrator & operator), PaulWurth (Engineering Procurement Construction company for hydrogen processing units), Sunfire (High Temperature Electrolysis, HTE, technology provider) and the world-class RTO CEA, coordinating the project. They focus on operation under realistic conditions and market frameworks to enable the commercialisation of the HTE technology. By demonstrating reliable system operation with a proven availability of ≥ 98 %, complemented by a benchmark study for stacks in the 10 kW range, critical questions regarding durability, robustness, degradation as well as service and maintenance are addressed.