A sustainable energy supply requires a stepped-up change to renewable sources of energy. By 2050, assuming the demand on the security of supply remains the same, at least 60 percent of the gross final consumption of energy in Germany is to be covered by renewable energy sources. A major challenge is the natural fluctuation in power output, particularly with wind and solar power. In order to guarantee a consistent supply of electrical energy, there are a number of flexibility options available to help balance out the difference between energy supply and demand. In addition to grid expansion, load management and the use of highly flexible conventional power plants, this includes the utilisation of suitable storage methods. Nanotechnology innovations are already contributing to improved energy conversion, storage and transmission. In future, nanotechnology solutions (including the targeted use of nanomaterials) could play a prominent role in the energy sector, especially in the development of innovative approaches to energy storage.