A system comprises a device (300) for receiving and transporting objects and a generator (402). The device (300) has an adjusting mechanism (305, 306) and a base (304) that can be adjusted in height by means of the adjusting mechanism (305, 306). The adjusting mechanism (305, 306) is designed in such a way that the base (304) can be lowered by a weight of objects received. The adjusting mechanism (305, 306) is also able to be connected or is connected to the generator (402) in such a way that the generator (402) is driven and converts mechanical energy into electrical energy while the base (304) is being lowered.