Thanks for reply.

Well, it is true that there lots of different 8051 in the world, so there must be some results received in power measurement at least for this microprocessor family, I am not talking for some specific one.
There is no doubt that there are lots of different factors will effect on final energy consumptions, but before such “exotic” situations as “sleep mode” or “interruptions” there should be some measurements during execution of a simple program, could be with different voltage supply, so to compare the same task in different conditions and so on.

Anyway somehow people measure and compare their new designs with previous ones and finally they present such result e.i. “out design consume less power and more power efficient as that one in the same conditions”.