In 2017, 44 percent of Bavaria's gross electricity generation was already covered by renewable energies in Bavaria (source: Bayerischer Energieatlas 2019, https://www.energieatlas.bayern.de). One third of this is generated by hydropower. By 2025, the share of "renewables" is to grow to 70 percent. Innovative solutions and research-based developments are needed to achieve this goal. With the "DEGREEN Project", sponsored by the Bavarian Ministry of Economic Affairs, the Fraunhofer ISC has opened up new avenues for the use of renewable energies.

Energy generation from water currently requires the use of water wheels, turbines, barrages, etc. The Fraunhofer ISC has developed new ways of using regenerative energy. The environmental changes associated with this as well as the optical, acoustic and biological disturbance factors are repeatedly the subject of public criticism.

The Center Smart Materials CeSMa of the ISC developed new technologies based on dielectric elastomer generators (DEG) for the effective, environmentally friendly generation of electricity from hydropower. The goal is modular DEG with an electrical output power of up to 1 kW. The DEG do not need the disturbing side effects of conventional technologies. Special elastomer films are used to convert mechanical kinetic energy from the water flow directly into electrical energy. The films are equipped with elastic flat electrodes and function like stretchable capacitors.

The greatest challenge lies in the composite material, so that the elastomer films and the stretchable electrodes can withstand the extreme loads caused by high mechanical alternating elongation and simultaneously high electrical field strengths. The service life should be at least 100 million cycles, which corresponds to a service life of at least 5 years. In previous laboratory tests, lifetimes of more than 10 million cycles under realistic loads have already been proven.

The DEG are designed in such a way that they can be operated silently in shallow and small waters without transverse structures. Thanks to their modular design, they can be adapted to the water conditions. Due to their design, they are completely safe for fish and are not affected by flood events.

In the "DEGREEN Project", environmental protection authorities, water authorities and hydraulic engineers worked together in order to incorporate specifications into generator development. The result is a self-sufficient and modular energy supply concept, which enables an effective, environmentally friendly and decentralized power supply in off-grid areas. Applications could be, for example, charging stations for electric bicycles installed independently of the mains on cycle paths.

Further information can be found in the following flyer of DEGREEN Project (German Version).