Micro energy harvesting is a relatively new discipline in the field of mobile power supply for small devices and off-grid applications. In particular, thermo-electric and piezoelectric energy conversion processes are applied here. In thermoelectric energy conversion, a temperature gradient is converted into electrical energy. Piezoelectric energy conversion is based on the generation of electrical voltages through pressure or vibrations. Systems designed by the Fraunhofer Energy Alliance can, for example, provide energy for the radio transmission of sensor signals during function monitoring in moving or remote plants.