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Author Topic: Can you use a optical fiber for electricity?  (Read 18989 times)

Offline yor_on

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Can you use a optical fiber for electricity?
« on: 06/03/2009 13:18:53 »
Which ways can we convert coherent light to electrical power.
Would it even work?

And what would the 'energy loss' be if we did so?


 

Offline Vern

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Can you use a optical fiber for electricity?
« Reply #1 on: 06/03/2009 14:57:25 »
I don't know if coherent light matters. Solar cells are still not efficient enough to get a reasonable pay back, the last time I checked. It costs about $20,000 for a roof size unit.

We have some sizeable power plants in our western deserts that use an array of mirrors to reflect sunlight onto a boiler. Each mirror has its own pointing motors and sensors. It is pretty efficient but the location is a long way from where the power needs to be used. Our government is planning to enhance the power grid to include these remote power producers.
« Last Edit: 06/03/2009 15:00:32 by Vern »
 

Offline tony6789

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Can you use a optical fiber for electricity?
« Reply #2 on: 06/03/2009 17:01:15 »
yea deserts are pretty much the best way of "using whats at hand"  but as for any other ways of using ANY type of light for elctricty i dont know of any other practical things besides solar cells
 

Offline yor_on

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Can you use a optical fiber for electricity?
« Reply #3 on: 06/03/2009 18:53:55 »
I meant like similar to this
http://www.freepatentsonline.com/4500803.html

We are going to have some really bad weather if 'global warming' is correct.
So we lay fiber cables at the bottom of our oceans, and dig it down.
And to transport electricity as light might mean less 'energy loss' perhaps?
also I thought we would 'standardize' it :)
 

Offline Vern

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Can you use a optical fiber for electricity?
« Reply #4 on: 06/03/2009 20:25:50 »
That is an interesting invention. Magnetohydrodynamics is something I know very little about. I know it works, but I suspect a fibre optic transmission line couldn't move much power. I'm sure the present designs couldn't. The current cables require an amplifier spaced every half mile or so to keep the signal pumped to strength. 
 

Offline syhprum

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Can you use a optical fiber for electricity?
« Reply #5 on: 06/03/2009 20:26:22 »
Converting electricity to light and then back to electricity is even less efficient than than using electricity to generate Hydrogen and then using the Hydrogen to generate electricity.
The best way to transmit electrical power is over regular high voltage DC cables, it might be possible to reduce the losses a little by using superconductivity but the economics are marginal.
 

Offline yor_on

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Can you use a optical fiber for electricity?
« Reply #6 on: 06/03/2009 21:13:53 »
"There have been a succession of newer transatlantic cable systems. All recent systems have used fiber optic transmission, and a self-healing ring topology. Late in the 20th century, Communications satellites lost most of their North Atlantic telephone traffic to these low cost, high capacity cables"

Does anyone know how do they solve the amplifying problem down on the bottom?
And if i remember right there are different materials inside a fiber to keep the coherent wave moving 'correctly' too?
 

Offline Vern

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Can you use a optical fiber for electricity?
« Reply #7 on: 06/03/2009 21:41:49 »
The undersea cables have amplifiers spaced at regular intervals. Electrical power lines are in the cables to power the amplifiers.

The glass fibre in the cable has a glass core surrounded by a glass sheath. The sheath is fabricated to give light a slightly faster speed than the core. This keeps the pulse in the centre so that it doesn't diverge in its direction of movement.   
 

Offline yor_on

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Can you use a optical fiber for electricity?
« Reply #8 on: 06/03/2009 22:22:33 »
Yep :)
So what we would need, would have to be some material that was nearly superconducting for it to work then.

Eh, you wouldn't happen to have one laying around Vern?
Just asking :)

Well, back to the drawing board, again.

 

Offline Vern

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Can you use a optical fiber for electricity?
« Reply #9 on: 06/03/2009 23:13:37 »
I think syhprum had the solution. Transfer power via high voltage DC current so you eliminate the RF losses. Then we use superconducting cable and so eliminate IR losses. Quick; lets file a patent :)
 

Offline yor_on

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Can you use a optical fiber for electricity?
« Reply #10 on: 07/03/2009 00:29:56 »
Come on, they're closing soon.
We better run.
 

Offline Chemistry4me

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Can you use a optical fiber for electricity?
« Reply #11 on: 07/03/2009 00:32:47 »
But they're open 24/7.
Are we going to sleep yet? :)
 

Offline yor_on

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Can you use a optical fiber for electricity?
« Reply #12 on: 07/03/2009 00:39:40 »
So nice of you to drop in Mr Chem.
I couldn't by any chance interest you in a new theory?
It involves waves that refuse to move,

they'll satisfy themselves by just doing 'it' instead..
The wave, I mean.

 

Offline Chemistry4me

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Can you use a optical fiber for electricity?
« Reply #13 on: 07/03/2009 00:41:30 »
Go on, tell me about this theory, please.
 

Offline yor_on

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Can you use a optical fiber for electricity?
« Reply #14 on: 07/03/2009 00:44:56 »
They are waves, ok.
But doing the wave.

Can you see the implications here :)
 

Offline Chemistry4me

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« Reply #15 on: 07/03/2009 00:50:02 »
Nope. I am afraid that I cannot see the implications here :(.
 

Offline yor_on

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Can you use a optical fiber for electricity?
« Reply #16 on: 07/03/2009 00:51:22 »
Ok, consider a spherical cow, no, I meant stadium.
then look at the gallery, see them sit, see them stand.
And now, the wave.

As you can see it's the absolute same, but totally different, like a mirror. And as Vern pointed out to me, we can patent it too.

---

Interested?
 

Offline Chemistry4me

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Can you use a optical fiber for electricity?
« Reply #17 on: 07/03/2009 00:52:37 »
You mean like a Mexican wave?
 

Offline yor_on

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Can you use a optical fiber for electricity?
« Reply #18 on: 07/03/2009 01:00:07 »
Sorry, You probably got stuck on that spherical cow. that was a colleague of mine who got herself hired by the American Dairy Council to help optimize their milk production. She went around to the pastures, to the milking stations, and she looked at the scaling of the distribution networks (definitely not scale-free), etc. After a few  months, she had her presentation prepared. The auditorium was packed. She puts up her first slide and says “First, assume a spherical cow….
 

Offline yor_on

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Can you use a optical fiber for electricity?
« Reply #19 on: 07/03/2009 01:07:24 »
Well Mexican waves or Kiwi waves, they will work, all of them according to my new theory. But it does not, and I will repeat this, not, involve spherical cows, only innocent waves. And as I know that you are in good renown at your local ocean, you apparently don't even need to blink, no matter what waves comes your way, I just thought it might be of interest.
 

Offline Chemistry4me

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Can you use a optical fiber for electricity?
« Reply #20 on: 07/03/2009 01:10:27 »
Indeed, very interested.
So what is your new theory?
 

Offline yor_on

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Can you use a optical fiber for electricity?
« Reply #21 on: 07/03/2009 01:14:56 »
Well as you know we are in a secured location here, but just to be totally secure I would suggest us both to lock ourself into our bathrooms and then flush down our keys. And whatever you do, unplug that computer before you lock yourself in. Internet is not a safe place to be, take my word for it. Then send me a post, I'll be waiting here.
« Last Edit: 07/03/2009 01:33:33 by yor_on »
 

lyner

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Can you use a optical fiber for electricity?
« Reply #22 on: 07/03/2009 11:48:12 »
As a method for transferring power (rather than information), optical fibres are a waste of time because of the absorption in the material. DC or low frequency AC through copper cable wins in every case - except when you can't achieve actual physical contact between the source and the consumer.
Light travels without loss through space. The problem is that it spreads out (however hard you try) and the good old inverse square law comes into play eventually. Lasers simply put off the problem a bit.

Light detectors / convertors are highly inefficient interfaces with electrical energy.  A more efficient way than using light would be to use a much lower frequency of Electromagnetic Wave. Microwaves can be generated with about 30% efficiency and can be received and rectified with a similar efficiency. (Very rough figures, of course)
Unfortunately, the 'spreading loss' over a long distance is enormous unless you use really vast reflectors to beam and receive the power.

It would be interesting to see what solution 'they' would use if they needed to feed substantial power (say, a few kW) across a gap of a few hundred km  with no actual physical connection. A hideously expensive problem to solve.
Possibly a high power chemical laser could be an answer.
 

Offline Vern

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Can you use a optical fiber for electricity?
« Reply #23 on: 07/03/2009 15:32:29 »

If I were to be the "they" I think I would consider Microwave Power Transmission
since we already have the technology pretty well worked out and know pretty well what the efficiency of transfer would be.

Quote from: the link
Microwave power transmission (MPT) is the use of microwaves to transmit power through outer space or the atmosphere without the need for wires. It is a sub-type of the more general wireless energy transfer methods.

Following World War II, which saw the development of high-power microwave emitters known as cavity magnetrons, the idea of using microwaves to transmit power was researched. In 1964, William C. Brown demonstrated a miniature helicopter equipped with a combination antenna and rectifier device called a rectenna. The rectenna converted microwave power into electricity, allowing the helicopter to fly[1]. In principle, the rectenna is capable of very high conversion efficiencies - over 90% in optimal circumstances.

Most proposed MPT systems now usually include a phased array microwave transmitter. While these have lower efficiency levels they have the advantage of being electrically steered using no moving parts, and are easier to scale to the necessary levels that a practical MPT system requires.

Using microwave power transmission to deliver electricity to communities without having to build cable-based infrastructure is being studied at Grand Bassin on Reunion Island in the Indian Ocean.
 

lyner

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Can you use a optical fiber for electricity?
« Reply #24 on: 07/03/2009 21:10:04 »
yebbut is it actually done?

I should have thought that the 'green' methods of wind and wave power would be far better value for an island. Either way, you would be talking of ££ per kWh, compared with the >=10p per unit in the UK.
« Last Edit: 07/03/2009 21:13:55 by sophiecentaur »
 

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