German Student Creates Device That Harvests Energy From Air
Dennis Siegel has created an energy harvester that can be used to harvest ambient energy from electromagnetic fields in the air, such as those present near power lines, plugged-in electric appliances, or mobile phones. Siegel is studying digital design at the University of Bremen. (Source: Dennis Siegel)
TANSTAAFL - Thair Ain't No Such Thing As A Free Lunch. A single wire transporting electrical energy which emits an electric field represents a certain parasitic load. When you run another single wire or device that couples the electric field of the first wire, you increase the load. Not unlike a transformer, thus as secondary current increases, primary current does as well. Wires that are designed to emit radiation (antenna's) emit the electrical energy as RF radiation and it can be harvested without diminishing the source, however the available current is miniscule. Charging a small battery in a day from radiated sources is pretty inefficient considering the wide range of other available energy sources.
I agree with Elizabeth: stealing implies that the thief takes away something so there's less of it. That's not at all the case here: this is harvesting secondary energy from a source which is primarily providing the primary energy. It's not like someone's house on the power line has less electricity available, or even that the power station at the source of the line has less energy available. This is using "waste" energy that's been previously unused. There's a lot of "waste" energy in the world created by various sources.
Well, I suppose you could look at it that way, dka, kind of like copying someone's CD MP3 collection. But I think that it's more using energy that already exists rather than stealing. And I'm pretty sure it's using the electricity that the wires themselves are emitting...I suppose they come from the power company originally, but at that point a case could be made that it is coming from the wires and perhaps even have its own existence, as it is now a part of the air. But I do see what you're saying!
Back in electromagnetic theory class we discussed the idea of building a car that could operate near power lines to do the same thing this kid is doing. There are power lines running alongside most roads anyway. The antenna would probably be unpractically large, and would have to be unpractically close to the wires to get enough power, but it's probably sorta doable. Either way, it's stealing because the energy coupled into the device only comes from the power company.
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