[varenc]

In the macro physics sense, all energy eventually becomes heat somewhere. My 1500W space heater is perfectly efficient and produces 1500W of heat, and my 1500W crypto mining rig does too. Thermodynamically there's no difference. Where would the energy go if not into heat? Even energy that does things like push air or emit radiation, eventually becomes heat somewhere. In the case of a power plant, that somewhere is just very far away with the end user.

Though there might be practical differences though between the excess heat intentionally exhausted, and other heat. Just speaking from a very macro sense.