Electricity from the air - Drayson's big idea

[Finishline42]

Electricity from the air - Drayson's big idea

Free energy from the air. It sounds like a fantasy but that is what the entrepreneur and former science minister Lord Drayson has just unveiled at London's Royal Institution.

He claims that a technology called Freevolt can be the power source for the "internet of things", allowing low energy devices from wearables to sensors to operate without being plugged in.

The technology involves harvesting radio frequency energy from existing wireless and broadcast networks, from 4G to digital television. Lord Drayson says it's a world first: "It doesn't require any extra infrastructure, it doesn't require us to transmit any extra energy, it's recycling the energy which isn't being used at the moment."

The technology was demonstrated in the lecture theatre at the Royal Institution, where Michael Faraday worked on electromagnetism in the 19th Century. Lord Drayson first showed how much radio frequency energy was in the room, and then used his Freevolt system to power a loudspeaker.

http://www.bbc.com/news/technology-34401616

[WDIM]

1. Free wireless energy is all around us all the time.

Its just a matter of harnessing it. That was Tesla's life work tapping into that energy source. Free energy would truly create more freedom and more possibility for the entire human race. That is why it has been withheld since Tesla.

[RKP5637]

3. Can't have freedom and free energy for humans, no way for the hucksters to

make $$$$$$$$$'s. Exactly!!!!!!!!!!!!

"That is why it has been withheld since Tesla."

Everyday mankind is F'ed over for $$$$$$'s. One stands back and looks at it in the big picture, it's pathetic.

[Kelvin Mace]

5. Hmmm....

I wonder about the economics of the matter.

But setting that aside, t would seem to me that if everyone started wearing these devices, the "net gain" in power would results in degrading of the signals in question, which means the signal transmitters would have to increase their power to deliver the same level of signal quality.

[rickford66]

12. You'd only "harvest" what you would absorb anyway.

Almost all radio signals are "wasted" in a sense, because we don't have receivers everywhere.

[cprise]

16. Radio waves also propagate *past* areas with no receivers.

Mostly they go through objects or bounce off.

If you're in a building where hundreds of these harvesters exist, the resulting 'shadows' in the signal would reduce your reception. And for people in nearby buildings.

I'm pretty sure this is already illegal. The transmitting parties have to increase their power to maintain the same coverage.

[WDIM]

14. If they can tap into that energy wave they can tap into others.

There is constant natural energy waves around everywhere.

[immoderate]

2. Beware, lest they see you coming!

I'm dubious. More Aircar.

--imm

[RKP5637]

4. He will likely meet with some strange unexpected accident for challenging the

$$$$$$$$$$$$'s of the takers.

[Travis_0004]

8. I doubt it

He manged to 'invent' something, that was actually invented in the 1920's with the crystal radio.

[phantom power]

6. good idea -- but my god, what a terrible headline

it's harvesting energy from our RF devices, not "the air"

[Travis_0004]

7. This isn't a new idea

Crystal radios have been around for almost 100 years. I've seen circuit boards with a small led light that pull in radio waves to power a small light. The light isn't much, and this was very close to an AM station transmitting at 50k watts.

[Binkie The Clown]

9. This is not energy for "free"

Any more than living under a high tension power transmission line and harvesting energy from it with huge induction coils on your roof.

Your simply taking energy that has been generated someplace else. There's no free lunch.

Now if we were to harvest the enormous static electric potential differences in the atmosphere at different altitudes, that would be something different. That would be tapping the energy that powers lightening bolts.

[Travis_0004]

10. I agree

My example was going to be if I put a turbine on a water main to generate power. Its free energy to me, but somebody has to pay. The people below me have lower water pressure, and if enough complain, the water company has to spend more energy to increase pressure.

I guess there could be a small difference. Most power from transmissions is absorbed by buildings, trees, etc. If my house blocks a radio signal, obviously the radio station has to accept that. If I have a watch powered by that signal seconds before my house absorbed it, whats the harm?

I would like to hear an electrical engineers opinion on this. Does a device pulling radio signals out of the air harm the signal, or would it have been mostly absorbed by the ground (or me) if it was not otherwise used. If there is no harm, then I have no issue with it, although its free energy. The radio station paid for it.

[rickford66]

13. see #12

You are correct. Unless a receiver converts the signals into something else (music for instance) the signal is absorbed somewhere and "wasted" so to speak.

[Finishline42]

11. There is this quote-" it doesn't require us to transmit any extra energy, it's recycling the energy"

There is this quote that is counter to your point - " it doesn't require us to transmit any extra energy, it's recycling the energy which isn't being used at the moment."

I don't know, not being in any way knowledgeable of what would happen to signals if hundreds or thousands were using devices that harvested electricity from those signals.

Unlike the example below of putting a turbine in a water line (that would pull energy from the water flow and create a resistance that would require additional energy to pump the water) - not sure this would affect the signal in any way.

[muriel_volestrangler]

15. Their claim seems to be for devices up to a smartwatch or smoke alarm

http://res.cloudinary.com/engineering-com/image/upload/w_640,h_640,c_limit/PowerGraph_awx5de.jpg

http://www.engineering.com/ElectronicsDesign/ElectronicsDesignArticles/ArticleID/10749/Freevolt-Grabs-Energy-from-the-Air.aspx

Here's their white paper, where that graph (ie the first link, which isn't displaying as a picture, annoyingly - click on that link, or the 2nd link for the articles it's in) comes from: http://www.getfreevolt.com/downloads/RF%20Energy%20Harvesting%20Whitepaper.pdf

However, that says the available power varies widely, which then seems to limit the use for the higher power items like smartwatches:

"Variations of power density were measured in a four-story
London office block. Measurements were taken across
different rooms and floors in the building as well as
numerous discrete locations in the offices.

Upper and lower WiFi frequencies had the highest average
power densities while the 3G (2100 MHz) and LTE (2600 MHz)
average power densities were the lowest. The highest peaks
recorded were in the sub-micro-Watt per square centimetre
range for both WiFi frequencies as well as the GSM/4G LTE
900 band, which were around 600-700 nW/cm2
...
The highest average power densities measured in outdoor
areas around London, were predictably in the GSM, 3G, and
4G bands. Peak power densities measured were in the
micro-Watts per square centimetre range for these cellular
bands, the highest being 6.7 uW/cm2 in the 3G band. In
comparison to office measurements, significantly lower
power densities have been measured for the WiFi bands
overall, with some peaks measured near tube stations.
...
the average RF density measured in an office or
external environment ranges from 20 to 35 nW/cm2"

which seems to put them at the low end of that RF range.