A comprehensive study of the crystal and electronic structures, thermodynamic, electrokinetic, energy, and magnetic properties of the semiconductive solid solution Lu_1-xSc_xNiSb, x = 0 – 0.10, revealed the possibility of doping Sc atoms of different crystallographic sites depending on their concentration. This leads to the generation of structural defects of donor and/or acceptor nature and the appearance of the corresponding energy levels (bands) in the band gap є_g. The ratio of ionized donors and acceptors (degree of compensation) determines the position of the Fermi level є_F in Lu_1-xSc_xNiSb. The dependence of the rate of generation of energy levels and the position of the Fermi level є_F on the impurity concentration Sc, which determines the mechanism of electrical conductivity of Lu_1-xSc_xNiSb, is established. The investigated Lu_1-xSc_xNiSb solid solution is a promising thermoelectric material.