@Bob- if we could harvest energy no matter how small it is, it's worth considering as very soon we will be short of power so saving it should be our primary objective. If we could harvest the energy / power wasted I think that's what is required.
@dka – I was just wondering how the power could be used for the car without touching the power lines. I was under the impression that power travels through wires and not over air. It's nice to see a student working on such a project.
I think that I have read that there have been successful prosecutions of those who did build systems to capture energy from some of those larger , longer, overhead transmission lines. I researched that after seeing that there was about a half mile of such line along the boarder of my uncle's farm. At that time a half mile of wire strung along the tops of fenceposts similar to an electric fence would be able to recover a useful amount of power. But the ruling that I saw claimed that since the power clearly came from the overhead line, that the act was indeed theft of services.
Tapping power from the ambient electrostatic field inside a structure is different for many reasons, starting with that area being "downstream" from the metering. But the voltage induced from the proximity to electrical wiring has a very high source impedance, with the result that not much power can be recovered. IT would be very educational to see waht the device produced by the student actually consists of. My bet is that a battery of some sort would be found, since in the area of the device in the photo there is not enough power available to even light the LED that we see. "If something sounds unbelievable, it probably is". I didn't say it first, but it is still true.
Elizabeth M, I agree very interesting comments and perspectives on this topic of harvesting energy and theft. I'm not quite sure if capturing "free" electromagnetic waves in the air is theft especially if the use is to charge up a battery for personal use. If that's the case, society as a whole has committed a criminal act by using standard FM/AM radios in automobiles. The RF signals are in the ether and antennas embedded within the car radio traps these signals, extracts the audio content, and society reaps the benefit of musical entertainment, educational enlightenment, and public awareness via music and talk radio shows.
Not only that, but it's charging with much greater inefficiencies than something plugged in directly. At the end of the day there is no free lunch, everyhting is tied together with varying degrees of loss. If it weren't so we would have had perpetual motion machines years ago. I would go as far as saying that there should be a massive tax on these significantly lossier chargiing systems, to help pay for the additional environmental damage they do. In the late 60's in Germany it was popular to have TV's designed do that the picture tube filament was permanently powered so that we would have instant on. That was around 6W plus losses for every TV in the country. Then they decided it was a bad idea environmetally. Now some other twit comes up with the idea of designing a lossy charging system for a multitude of battery devices. How before the ~1W of additional loss times ten times as many devices is concidered unacceptable? Here's me thinking engineers thought ahead??
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