The transition to a sustainable energy system requires the deployment of a range of efficient technologies for the conversion, storage and distribution of renewably-generated power and heat. The IEK-3 is at the forefront of this endeavor. In collaboration with national and international partners from research and industry, we develop solutions for mobile and stationary applications and conduct groundbreaking research into Electrochemical Systems and the use of hydrogen as an energy carrier, including its production, distribution and storage. Additionally, we formulate concepts and models for the energy system of the future.