Unless video card manufacturers , for example, would include some kind of 'hardware' wattage measuring device on the actual card and then a software became available to monitor that installed hardware device, that kind of 'power' usage monitoring is not possible. Of course, I would pay $13.99 for a kill-o-watt device and know how much wattage my system is using at any given time before I would pay $1700 for a wattage-monitored enhanced Radeon 1550. LOL.
Watt am I saying, I have a Kill-o-watt device that is capable of telling me how much 'power' my system is drawing at any given time.