A sensor system for a machine tool with at least one sensor with at least one measurement instrument, which measures a physical quantity occurring within the machine tool, which is related to a machining process performed by the machine tool; with a first energy supply for supply of the at least one measurement instrument of the sensor, wherein the first energy supply receives electric energy from a surrounding electromagnetic field in a wireless way; and with a second energy supply for supplying the at least one measurement instrument of the sensor, wherein the second energy supply comprises at least one battery.