A vessel has a feed display unit which is powered by the temperature difference between the liquid in the vessel, a thermal power generator. Heat from the liquid is used to generate electricity using a thermoelectric power generator and the heat sink or radiator by thermal contact with the liquid. It can be used to generate electricity by temperature difference of cold liquid also outside the container in the container. Feeding display unit to be powered, the light-emitting diodes in a flexible material, an organic light emitting diode, a liquid crystal display device, the light emitting tube, fiber optic devices, can be configured by other light emitting structures.