Tesla's World Wide Wireless Power Tower | Hacker News Reader

Tesla's World Wide Wireless Power Tower

damninteresting.com

22 pointswolfish11 comments

I've heard so many stories of the much abused and misunderstood Tesla, usually coming from people I'd politely call "free-energy wackjobs". Even this article, which is one of the fairer versions I've heard, doesn't touch on why this has never been implemented or experimented upon further. It can't be for lack of interest or ignorance or for startup cost either (or else I'm sure YC would have funded someone to build these towers).

So HN, anyone with more electrical knowledge than I know why this doesn't work or why it wouldn't scale or any other engineering challenges that have kept this from being more than a pipe dream?

This has been implemented: in every RFID reader. The difference between this thing and a radio is that this thing supplies its own power; RFID tags get their power from the radio transmission. You may have noticed, however, that RFID tags generally only work at very short ranges.

There are a few major reasons that this doesn't scale, but the big one is the inverse square law. The efficiency of the system is inversely proportional to the square of the distance between the user and the tower, whereas the efficiency of wires is inversely proportional to only the length of the wire.

I am not, by far, an electrical engineer/scientist, but the inverse square law applies to vacuum. All the details about Tesla using the Earth and the ionosphere as a conductor may have meant that he was trying to solve the power loss problem. Do we have any details on that angle?

I know nothing about electrical engineering but there was a documentary on the history channel about this and they interviewed the leading researcher(a professor in the US) and he basically said no ones ever built a tower the size of Teslas to actually test if his theory would work, it didn't get into the details of why the experiment couldn't just be scaled down. But I think he implied there was some sort of critical size you need to get to where it would become efficient.

Main problem, electricity arcs to ground ASAP. This means that the system can basically only have two connections in range of each other, so 1 power plant to 1 user. The economics of this doesn't really work well.

Generally electricity only arcs once, and it requires 30kV/cm. This means to arc to two things at 10 cm you require about 600kV, but again this requires a small amount of energy to be transferred to ground.

Transferring through the ionosphere would likely resolve some of this problem, it's like dipping electrodes into salt water. It works, it's just omni-directional and subject to the environment. However, you basically have to build every antenna 50km high.

The technology I believe is credible, but the practicality of it isn't very high. Below the ionosphere this technology has the problem that the ground is usually much closer than the next persons house. This would work great above 100 ft, due to the fact that the whole ozone production would poison most people. Above 100 ft, I can only transmit power in a range of less than 100 ft, but generally only to one person. If I want to transmit to two people it has to be below 50 ft.

At 100 ft the voltage limit is 90 million volts before you're arcing directly to the ground. The safe limit would probably be 45 million volts as you'd be arcing to peoples heads at 90 million volts.

Basically how the system would end up breaking down is that you'd use hundreds of feet of cable to connect to your antenna, which we currently use less to connect to the one down the road. I believe mine is about 30 feet away. The substation would require a few thousand feet or so of cable to connect to the main transformer, again which we use considerably less to do today.

So the only practical usage I see is on the long distance scale, where you're using the ionosphere instead of arcing through the air. However, it would all have to be over 100km apart. Yet at such extremely high voltages to be practical we wouldn't have a strong enough insulator to stop the arcing anyway.

Unless we end up with like 2 power stations in North America and a super electrical insulator, I doubt this technology would ever become truly practical.

Do you have a blog about your projects?

I remember reading this when it was originally posted to DI's site a couple years ago. Pretty cool stuff, I'm sure some folks here who haven't read this will appreciate it. DI truly has some Damn Interesting articles!

Ah yes, a staple from the golden age of reddit. Anyone know why they haven't written anything since October?

I think they stopped posting while they work on their book but I could be wrong.

I had a wonderful physics teacher who brought in a bunch of different inventions made by Tesla and I always thought they were interesting but the theory of wireless electricity is so different to people it always blows my mind that it works ,despite all the physics attributed to it, if this becomes popular soon we will have to find a phrase to replace "plugged in."

Tower of Power reminds me of Frank Zappa :-)

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