This project mainly focuses on the stack development to reduce costs and extend lifetime. For this purpose, several work packages ("development of new materials", "powder development", "cell development" and "stack development") will be carried out. An annual release of those measures is planned in order to achieve a constant cost reduction throughout the project. At the same time, the development of the offgridsystem is taking place. At the end of the project, a fully functional prototype with significant cost reductions will be built and operated. At KIT components, single cells and repeat units will investigated to develop models describing losses and aging mechanisms and enabling a model-aided development of the stack.