Monitoring power consumption on Mac The Android OS monitors the power consumption of running apps and hardware (display). As you may guess, this is a useful feature as it allows to track down energy greedy apps.

Is there an application that would do such monitoring on Mac OS?

It should calculate the percentages of the charge that an application/process/hardware has used.

I use plenty of little software that runs in the background permanently. It would be nice to know if such little helpers drain the battery significantly.
As of Mavericks, this is provided by the OS. Activity monitor has a tab devoted to displaying the energy use of running (and recently running) apps.

Also, the battery icon shows applications that use significant energy on Mavericks and newer.