The energy saving resulting from the equalization of Fermi energies of a crystal and its melt is added to the Gibbs free-energy change G 2ls associated with a crystal formation in glass-forming melts. This negative contribution being a fraction ε ls (T ) of the fusion heat is created by the electrostatic potential energy −U 0 resulting from the electron transfer from the crystal to the melt and is maximum at the melting temperature T m in agreement with a thermodynamics constraint. The homogeneous nucleation critical temperature T 2 , the nucleation critical barrier G * 2ls /k B T and the critical radius R * 2ls are determined as functions of ε ls (T ). In bulk metallic glass forming melts, ε ls (T ) and T 2 only depend on the free-volume disappearance temperature T 0l , and ε ls (T m ) is larger than 1 (T 0l > T m /3); in conventional undercooled melts ε ls (T m ) is smaller than 1 (T 0l > T m /3). Unmelted intrinsic crystals act as growth nuclei reducing G * 2ls /k B T and the nucleation time. The temperature-time transformation diagrams of Mg 65 Y 10 Cu 25 , Zr 41.2 Ti 13.8 Cu 12.5 Ni 10 Be 22.5 , Pd 43 Cu 27 Ni 10 P 20 , Fe 83 B 17 and Ni melts are predicted using classic nucleation models including time lags in transient nucleation, by varying the intrinsic nucleus contribution to the reduction of G * 2ls /k B T . The energy-saving coefficient ε nm (T ) of an unmelted crystal of radius R nm is reduced when R nm R * 2ls ; ε nm is quantified and corresponds to the first energy level of one s-electron moving in vacuum in the same spherical attractive potential −U 0 despite the fact that the charge screening is built by many-body effects.