Searching for information about transmission of energy

Thread Starter

buzzshadow333

Joined Nov 29, 2020
8
I have worked with alternative energy systems for years and came across this site searching for information about transmission of energy (usable power) from things such as space based solar energy generation.
I was following the conversation from somebody, on this site, that wanted to transmit microwave power to a remote battery powered device.
The distance is supposed to be 100's of meters and I was quite interested in the possibility of doing so and how feasible the success
of such a setup. Very much interested in specifically what equipment is necessary, approximate initial cost, how safe, etc...
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Wolframore

Joined Jan 21, 2019
2,193
Very impracticable and inefficient. Is it possible, yes but so is a dog walking on his hind legs.
Hey buddy, I would love to hear your reasoning.

This ones an interesting, NASA has done this as well as Japan and currently there’s plans to do this in Australia. There are issues with it but the best overall efficiency is about 75% while the relay (if needed) are nearly 100%.

it solves some issues of using copper which has power loss as well.

Im skeptical... it will need alignment and obstacles may cause concerns. A directional microwave beam with considerable power is dangerous.

Im not clear of what the cost of this would be. Copper also has a high cost.
 

Papabravo

Joined Feb 24, 2006
14,868
One of the flip sides of this, is energy harvesting. The theory is that there is all this RF energy from a variety of sources, that is available for harvesting. The power levels are incredibly small (femtowatts), but yes you can do it. One of the things that gets in the way is that there is an inverse square law that attenuates the available power by a factor proportional to the square of the distance.
 

nsaspook

Joined Aug 27, 2009
7,891
Hey buddy, I would love to hear your reasoning.

This ones an interesting, NASA has done this as well as Japan and currently there’s plans to do this in Australia. There are issues with it but the best overall efficiency is about 75% while the relay (if needed) are nearly 100%.

it solves some issues of using copper which has power loss as well.

Im skeptical... it will need alignment and obstacles may cause concerns. A directional microwave beam with considerable power is dangerous.

Im not clear of what the cost of this would be. Copper also has a high cost.
This technology is neither new or novel. The mathematics for far-field energy dissipative transmission are brutal when it comes to actual power transmission vs near field reactive transmission in copper wire. A 75% transfer of energy across 100's of meters is just not going to happen with practical consumer devices. For high value military and space based operations the total system costs of each KWh might be tolerated.
 

Papabravo

Joined Feb 24, 2006
14,868
...
it will need alignment and obstacles may cause concerns. A directional microwave beam with considerable power is dangerous.
...
My friends who do DX'ing at UHF and above actually use rifle scopes to line up the receiving and transmitting antennas. It is not power transfer, but information. Tens of watts and damn fine receivers will get you a kilometer or so at 403 GHz.
 

Wolframore

Joined Jan 21, 2019
2,193
We used to do up to about 180 miles (~300 km) or more by bouncing microwaves off the ionosphere but again, a different concept... it scatters the radio waves and would be inefficient for power transmission. It would need a tight guide tube and to keep the transmission tight it will need a different sort of antenna. Would need some calculations to maintain as much on receiver to determine antenna size and spread. It will not be cheap, so unless you have some deep pockets, it's outside of consumer development/use. It's proven so it's possible just will mean a lot of R&D and some costly custom equipment.
 
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nsaspook

Joined Aug 27, 2009
7,891
We used to do up to about 180 miles (~300 km) or more by bouncing microwaves off the ionosphere but again, a different concept... it scatters the radio waves and would be inefficient for power transmission. It would need a tight guide tube and to keep the transmission tight it will need a different sort of antenna. Would need some calculations to maintain as much on receiver to determine antenna size and spread. It will not be cheap, so unless you have some deep pockets, it's outside of consumer development/use. It's proven so it's possible just will mean a lot of R&D and some costly custom equipment.
Like I said.
dogs_on_hind_legs_10.jpg
 

nsaspook

Joined Aug 27, 2009
7,891
Will have to see how these tests go: possible commercial application
https://newatlas.com/energy/wireles.../?itm_source=newatlas&itm_medium=article-body
Sounds like a lot of hype to me. The relays (I assume this means back-to-back antennas) are low loss if well designed but the electronics and systems are not lossless, the transmission media (space) is not lossless, it's dispersion because the beamed energy spreads out and some is absorbed in atmosphere even with the best lensing systems with coherent radiation.
So the total system is sitting around that 70-percent mark then?

Pretty much, it depends.

"I think we stack up fairly well."
is the answer in a comparison with copper wire @ 10-15 percent transmission losses being a worse case usually.

Smoke-and-mirrors with no maximum theoretical efficiency as an answer.

I would think the actual system end to end efficiency is much like the old NASA system in the range of 50-60 percent at a few tens of KW. A typical 230 kV line might carry 300 MW on each circuit, imagine the magnitude of losses with this system even at 70 percent end to end efficiency.
 
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nsaspook

Joined Aug 27, 2009
7,891
Easily cured by underground utilities at great expense to the rate payer. The wireless systems talked about here are not a solution for local distribution networks and only would be useful in a limited number of utility-grid level links.

Any claim that uses the name of Nikola Tesla as reference to its technology has a huge credibility gap IMO.
 

Papabravo

Joined Feb 24, 2006
14,868
@nsaspook The ignore function makes it hard to follow what looks like a conversation between yourself and an unknown participant. Keep it up, I'm enjoying it immensely. Probably the mods will lock the thread because it has been 'jacked
 

nsaspook

Joined Aug 27, 2009
7,891
Well, if it’s anything like solar the efficiency will improve given enough work and time. What do you have against Tesla?
Just like with Solar's top efficiency there's a little problem with physics that limits the efficiency of far-field wireless transmission of power. Tesla was a great engineer for the 1880's. Most of his purely scientific ideas were wrong (especially his ideas about physics of electrical energy and transmission) long before he fell off the deep end near the end of his life.

1/3rd genius, 1/3rd eccentric visionary and 1/3rd looney tunes.
 
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Papabravo

Joined Feb 24, 2006
14,868
Just like with Solar's top efficiency there's a little problem with physics that limits the efficiency of far-field wireless transmission of power. Tesla was a great engineer for the 1880's. Most his purely scientific ideas were wrong (especially his ideas about physics of electrical energy and transmission) long before he fell off the deep end near the end of his life.

1/3rd genius, 1/3rd eccentric visionary and 1/3rd looney tunes.
Sounds like some of our contemporary wunderkinds.
 

andrewmm

Joined Feb 25, 2011
909
Referring to the original question
transmission of power via microwaves.

Transmission of power over the air is as has been said, very common,
for most, the power level is small, so a receiver that needs its own power system is needed.
its commonly called radio or wireless.

To transmit real useful power, Mr tesla had a few ideas,
resonant receivers and such like,
but basically its the same as radio,

the hard part is getting the efficiency up,

You either keep the Tx and Rx close, as in wireless charging of mobile phones,
or you focus the power, using some sort of beam forming, an aerial is common,
thought electronic forming is possible,

This is typically called radar.

The reason to use microwaves, is that the wave length is relatively short, such that a relatively small high gain antenna can be used to passively increase the localised power.

works great,

But worry with microwaves, is high power microwave is not beneficial to human life,

that's called a microwave oven.


They have been considered a few times in space,
the receivers on the earth being a long way from habitat areas,

https://www.bbc.com/future/article/20201126-the-solar-discs-that-could-beam-power-from-space


The constant argument is that a RF power source in space that can put that sort of power onto the ground,
also makes a fantastic first strike weapon.

https://www.thedrive.com/the-war-zo...tial-orbital-microwave-anti-satellite-weapons
 
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