Johannes Wüllner studied environmental engineering in Trier, Germany and received his degree with distinction in industrial engineering from the Environmental Campus in Birkenfeld. Already during his studies he was intensively working in fuel cell research. During this time he found his passion to renewable energies and to the challenge to store this energy. His professional career started in 2007 at Concentrix Solar as system R&D engineer. There he covered a key role in developing the first industrial scale CPV Systems and its roll out. In 2012 he set up and led a new group on Energy Storage, Energy management & isolated Diesel-Hybrid Projects. After 8 years in R&D he moved to South Africa to set up his own company, focusing on Operation and Maintenance for Renewable Power plants. Since December 2017 he is back in Germany, leading the research group in applied energy storage systems at Fraunhofer ISE in Freiburg.