[en] Thermal electromotive force (e.m.f.) has been studied in the samples of the system ZrO₂-Sc₂O₃ in the composition range 8-100 mol% Sc₂O₃ at 900-1200 deg C and PO₂ from 1 to 1.3x10^-4 atm; the heat of oxygen ion transfer has been calculated. In a monophase region of solid electrolyte containing 8-30 mol.% of Sc₂ω₃ the slopes of thermal e.m.f. curves, concentration of oxygen-ion vacancies, and partial pressure of oxygen in a gaseous phase are equal to theoretical: 9.94x10^-5 and 4.96x10^-5 v/deg, respectively. The heat of oxygen ion transfer for electrolytes depends on the composition and is about 60% of the conductivity activation energy which agrees with a kinetic interpretation of the heat of transfer. It has been shown that the boundary electrolyte-semiconductor can be determined by a sharp change in the thermal e.m.f. value