http://www.technologyreview.com/view/538031/first-demonstration-of-a-surveillance-camera-powered-by-ordinary-wi-fi-broadcasts/

Electronics bleed.  I mean, if energy serves as the lifeblood of any bit of tech, then I think we can make that metaphor work, right?  There is energy all around us, there is the solar energy that gets dumped on our planet by the tanker-load every minute of every day, there is the lost energy in the form of heat that bleeds from our car engines as they sit, cooling with no more than an occasional crackle or ping, in our garages at night.  There is the extra kinetic energy lost when your fingers mis-type letters on a keyboard, or when you idly spin your office chair around in circles.

As we move forward, we are going to need to think differently about recapturing energy, there are going to be a host of inventions, big and small, that will help us to achieve even greater levels of efficiency.