Use waste heat to generate electricity
Energy lost from hot engines and power plants could be converted into electricity by thermoelectric devices, thereby increasing the amount of useful power we get for a given amount of fuel.
Industiral smokestacks emit—and thereby effectively waste—vast amounts of heat each day. The wasted energy could be recycled by retrofitting waste heat recovery boilers to convert the heat to electricity.
In essence, the heat is harnessed to turn water to steam that turns a turbine to generate electricity.