This article describes a new concept of the thermoelectric power generation from the immense low-temperature heat sources. The thermoelectric junction to be used for the present purpose is a new p-n junction consisted of Fe12pctAl12pctSi(p) - Fe12pctAl(n) (pct. in weight) which exhibits a thermoelectric power as high as 70microV/K and relatively high electrical conductivity even at low temperatures, and which can be manufactured on an effective mass production basis. Important issue of this study is the heat-exchange type multi-stage thermoelectric generation system. Theoretical approach was dealt with in order to organize the system so as to make the electrical recovery efficiency close to 80 pct.