Dear Student,
On increasing temperature of a conductor, the kinetic energy of the molecule increases. As the kinetic energy of molecule increases ,the rate of collision of molecule with other molecule increases. Due to which the the resistance of the conductor increases.
Heat energy(electrical energy) transferred per unit time = V2/R
V is potenial difference
R is resistance
As R increseses ,therefore Heat energy or electrical energy per unit time decreses.
Regards