This is still in the testing phase, but real time power useage will soon become a reality for those that have electronic power meters.
It has been shown that people drastically reduce their energy consumption when they have a way to measure what consumes the most energy.
( Something that those of us that have Kill-A-Watt meters know well
)
Google PowerMeter
( Be sure to check out the link to the YouTube video on their page - it is to the far right of the page. )