It is shown that a special form of the compensation theorem for a receiving antenna leads to the explicit expressions for the internal electromagnetic power and energy dissipated in the Kirchhoff equivalent circuits thereby illuminating its interpretation. The main ingredient in the analysis is the Lorentz reciprocity theorem of the time-convolution type. The final results are given in both the time and (real-) frequency domains. The validity of the presented results is illustrated with the aid of the antenna optical theorem applied to small antennas and a numerical study concerning a planar antenna.