Can We Harvest Energy from Radiowaves?

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Discussion Overview

The discussion revolves around the feasibility of harvesting energy from radiowaves, particularly those generated by artificial sources such as mobile phone base stations and radio transmitters. Participants explore the potential for using this energy to power low-energy electronic devices, considering both theoretical and practical implications.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • Some participants suggest that it is theoretically possible to tap into electromagnetic waves for energy, drawing parallels to ocean wave energy harvesting.
  • One participant recalls past experiences with crystal radios, indicating that while it is possible to harvest energy from radiowaves, the energy yield was minimal and primarily demonstrative.
  • Another participant mentions Nokia's attempts to develop technology for passive energy regeneration from ambient radiation, although they note that current methods involve piezoelectric technology rather than radiowave harvesting.
  • Concerns are raised about the weak nature of the signals and the need for amplification to make them usable, with some suggesting that a multitude of sources in urban areas could potentially compensate for this weakness.
  • There is speculation about future advancements in nanotechnology that could allow devices to consume very little power, potentially making radiowave energy harvesting more viable.
  • Some participants express skepticism about the practicality of using radiowaves for energy, emphasizing the challenges of signal strength and the need for local power to amplify received signals.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the feasibility of harvesting energy from radiowaves. While some express optimism about future possibilities, others highlight significant technical challenges and limitations.

Contextual Notes

Participants acknowledge the weak nature of radiowave signals and the necessity of amplification for practical use, which raises questions about the overall viability of this energy harvesting method.

henrikb
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"Tapping" radiowaves for energy?

One thing I have been thinking about lately is if it is possible to "tap" the electromagnetic waves surrounding us for energy in the same way it is possible to tap the waves of an ocean for their energy.

I'm speaking of both natural electromagnetic waves but especially artificial waves caused by, for example radio transmitters; mobile phone base stations, wlan access points, FM/AM radio transmitters, etc.

Is it possible to take advantage of these "wireless" power suppy units somehow? For example to drive very low energy consuming electronical devices?



Henrik
 
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henrikb said:
... is [it] possible to "tap" the electromagnetic waves surrounding us for energy

Fifty years ago, it was fun to build a crystal radio, then build another wideband radio (which would not separate the stations from each other), and use that energy to power an audio amplifier to make it easier to hear the crystal radio. So, yes, it is possible, but the energy was not worth the effort other than as a demonstration.

Neil
 


Actually, if memory serves, Nokia is attempting to do just this as a form of passive regeneration of power for their cell phones. A quick google search should find what I'm talking about.
 


Is it possible to take advantage of these "wireless" power suppy units somehow? For example to drive very low energy consuming electronical devices?

likely not the way you mean...a radio (receiver), a TV (receiver), and a fiber optic cable for example, require amplification using local power at the receiver to boost the very weak signal received over the air to a usable level...

But you can tap the electromagnetic energy from lightning (perhaps),but it moves around too much I think, and of course sunlight via photoelectric cells and solar heat collectors of various types...
 


Naty1 said:
likely not the way you mean...a radio (receiver), a TV (receiver), and a fiber optic cable for example, require amplification using local power at the receiver to boost the very weak signal received over the air to a usable level...
I understand that the signals are very weak, but I was hoping that the multitude of sources around us - atleast in a metropolitan area - would compensate for this. Also, incorporating antennas "tuned" for the most usual or most powerful sources rather than a wideband solution could help?

Also, I was perhaps thinking a bit into the future with nano technology devices, which hopefully will consume very little power. On the other hand, if they do consume very little power, maybe it's easier to incorporate a very small battery into the device? But then maybe this battery could be constantly charged by the very weak signals.

My reasoning then becomes; if a device consumes very little power, the weak signals could actually contribute significantly :)
 


Pengwuino said:
Actually, if memory serves, Nokia is attempting to do just this as a form of passive regeneration of power for their cell phones. A quick google search should find what I'm talking about.
Interesting and yes, Google served up the following result

http://www.psfk.com/2010/03/nokia-developing-self-charging-phone.html

but it turns out they use piezoelectric technology to get energy from the motion of the mobile phone's owner.
 


henrikb said:
Interesting and yes, Google served up the following result

http://www.psfk.com/2010/03/nokia-developing-self-charging-phone.html

but it turns out they use piezoelectric technology to get energy from the motion of the mobile phone's owner.

No that's not in, although good find. They announced research into it earlier last year. It may not have been Nokia either. One of the major cell phone manufacturers is going to try to passively recharge using the typical amount of radiation you have in a major city just flying around.
 


Pengwuino said:
No that's not in, although good find. They announced research into it earlier last year. It may not have been Nokia either. One of the major cell phone manufacturers is going to try to passively recharge using the typical amount of radiation you have in a major city just flying around.

I did some more googling and it turned out there already was a thread about this here on this forum, and yes, it was Nokia:

https://www.physicsforums.com/showthread.php?t=320335
 

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