On 15 September 2017, DLR inaugurated the TESIS thermal storage facility at its Cologne site. From left to right: Prof. Karsten Lemmer, DLR Executive Board Member for Energy and Transportation; Ursula Borak, head of the sub-division 'Fundamental Questions of Energy Policy' at the German Federal Ministry for Economic Affairs and Energy (BMWi); Dr. Antje Seitz, DLR Institute of Engineering Thermodynamics; Prof. André Thess, director of the DLR Institute of Engineering Thermodynamics.