The difference between DC input power and RF output power of a transmitter RF amplifier:

No amplifier is 100% efficient. When a transmitter's RF amplifier consumes DC input power, it converts a portion of that energy into usable RF output power. The remaining energy that is not converted into RF does not simply disappear; the laws of physics dictate it must be conserved. In electronic circuits, this wasted energy is dissipated as heat. Distractors like "radiates from the antenna" or "is lost in the transmission line" represent what happens to the actual generated RF output power, not the inefficiency gap between the DC input and the RF output.