The grid inverter feeds electricity into the public supply grid in accordance with VDE AR-N 4105 up to an output of 15 kVA. In combination with an integrable frequency converter for high-speed generators, the feed-in system represents a complete solution for the operation of ORC systems (Organic Rankine Cycle). It can be used with hot gas or micro gas turbines as well as high-speed flywheel mass storage systems.