At the New Yorker Summit, Google's Dan Reicher mentioned the company's PowerMeter, an upcoming product/service that will measure household power use.
Google PowerMeter, now in prototype, will receive information from utility smart meters and energy management devices and provide anyone who signs up access to her home electricity consumption right on her iGoogle homepage. The graph below shows how someone could use this information to figure out how much energy is used by different household activites.
Felix Salmon lays out the rationale:
The behavioral sociology of measuring energy usage is simple: the more you know about how much energy you're using, the less you use. Just getting the information cuts most people's energy usage by somewhere between 5% and 15%, while people with high electricity bills (like me) find it much easier to isolate exactly what is causing those bills and can then work out how best to reduce them through upgrading appliances or replacing incandescent bulbs with CFLs or any number of other routes to energy efficiency.