GM250-161-12-20 Adaptive Thermoelectric Power Generator (TEG) Module 161 Couples, 3.27W 11.25V 0.58A, 40x40mm

Thermoelectric generators (TEGs) generate electricity from a temperature difference with no moving parts using the Seebeck effect.
Most energy losses are lost in heat and most heat sources are static. Today, thermoelectric technology works best where the power output required is up to 70W. This is suitable for sensors and other low power electronics in most types of industrial applications.