Seebeck effect states that when junctions between two materials are placed at different temperatures in a closed circuit
a voltage is developed in the circuit and is proportional to the
temperature difference between the junctions and the materials in the circuit.
This principle can be used in utilizing the waste heat from a stove. In the flame if one junction is placed, and the other junction is placed at room temperature, there would be a vast difference in the temperature difference between the 2 junctions. Seebeck voltage is usually of the order of few millivolts for 30 to 100 C but this difference in temperature would lead to the production of a few volts and a mild current in the order of milliamps flowing between the junctions. If this voltage is tapped, it could be used to light a bulb in the kitchen.
The bulb would glow from dimmer to brighter when the stove is switched on and when switched off the bulb would glow dimmer and dimmer and finally go off. This miniscule electricity saving may seem insufficient, yet over the years it leads to cumulative gain, with meager installation costs in comparison to the saving. Also, this can be done in places without electricity or cooking during a power failure.
Today the world runs on the depleting fossils which are on the brink of extinction. Any energy saved today is energy gained tomorrow. Though small, this may be one of the good ways to save energy.