The thermoelectric conversion offers unique possibility of a gigantic
electric power generation utilizing low-temperature heat sources below
600K. Such sources are solar heat, terrestrial heat and exhaust waste
heat from the central-station steam-electric plant. They are thermody
namically low grade but infinite and gratis. The immense production of
electricity by this principle is made possible exclusively by means o
f the thermoelectric junction between the iron-based: alloys as the co
nversion materials because these components of the generator can be ma
nufactured on an efficient mass production basis. Among several possib
le thermoelectric junctions basically consisted oi iron, the Fe13%Al12
%Si (p)-Fe12%Al (n) alloy couple has been found to exhibit a relativel
y high value of thermoelectric power, 71 mu V/K. The merit of tl-its t
hermoelectric power junction with respect to the thermoelectric conver
sion has also been described by measuring other thermoelectric propert
ies of these elements.