The project consists of two parts 1. Building a test facility for testing electrolysis systems 2. Conduct tests with electrolysis for the production of hydrogen and oxygen and how residual heat can be utilized. The test facility will be used for academic and scientific research to provide relevant results by mimicking the large-scale facilities planned in the steel industry in Norrbotten. The project includes design, construction and operation. The tests are focused on creating reliable and supplier-independent data that can form the basis for planning operations and maintenance in large plants. The results will be public and will be of benefit to anyone interested in large-scale electrolysis. The focus is on the transient behavior of the electrolyzer and the special difficulties that can arise when operating in cold climates. The long-term tests will be documented with the aim of creating a basis for operational strategies that can balance the grid .