IN COUNTRIES where mains electricity is unreliable or nonexistent, placing a grid of heat-resistant thermocouples onto a cooking stove could generate enough power to run a few light bulbs or a television.
The idea comes from Mike Rowe at Cardiff University, who has been working on ways to improve the efficiency of generators that use the “thermoelectric effect”. In a loop made of two dissimilar metal wires joined end-to-end, current will flow if the junctions between the metals are maintained at different temperatures. And the process is reversible: applying a current causes a temperature change at the junctions.
Thermoelectric generators…


