Essay:Nikola Tesla's Wireless Power Transmission

Much interest has recently been given to the life and work of Nikola Tesla, both from mainstream and fringe sciences alike. This essay will give my understanding of Nikola Tesla's hypothesis for wireless power transmission. Hopefully the members of Rational Wiki with a larger science background will be able to guess if it could hold water or not.

Be Warned!
There is a huge number of cranks and conspiracy theorists on the Internet who attempt to use Tesla's name for their own purposes, or incorrectly interpret his ideas. Tesla also had many ideas that would be considered woo. Whether or not this topic falls into that category is debatable.

Introduction
Nikola Tesla was a Serbo-Croatian (that is how it's spelled, isn't it?) born in July of 1856. He sailed to New York City in June of 1884, in the hopes of working for Thomas Edison. Edison did give him a job; however, the two disagreed on which form of electricity- Alternating Current (AC) or Direct Current (DC)- worked best. Edison, having designed his whole monopoly of electrical inventions to run on DC, supported the latter. Tesla supported the former.

Officially, Tesla left Edison for this reason. There are other claims that Tesla left after he was promised a $500,000 bonus to redesign Edison's electric generators, and failed to receive the bonus (apparently, Tesla didn't understand what Edison claimed to be "American humor").

Later on, Tesla would team up with one George Westinghouse. With Westinghouse, Tesla would win this dispute between electrical standards, called the War of the Currents, by electrifying the 1893 World's Columbian Exposition with AC power. It is worth mentioning that Tesla played a major role in inventing the AC motor, generator, and distribution system.

1891, Tesla engineered his most infamous creation, the Tesla Coil. Technically speaking, it is a high-voltage, high-frequency, resonant step-up transformer, and I will go into what this means later. It was originally devised as a power source for a high-frequency lighting system (the precursor to modern CFL's), but Tesla later discovered that radio-frequency waves traversed the air much more easily than lower frequencies. His investigations laid the foundation for modern radio as we know it.

Another use Tesla had in mind was for practical power transmission. He found that two Tesla Coils tuned to resonate (electrically vibrate on the same frequency) with each other would send electricity across only one wire. Under ordinary conditions, this is impossible; electricity needs a closed circuit for it to flow. This phenomena required certain conditions to exist:


 * The two coils need to be tuned so that they electrically vibrate on the same frequency. Compare this to tuning a radio - use the right frequency to get a clear signal from the transmitter.
 * The length of wire used in the secondary coil of the transformers must be 1/4 the wavelength being used. This would cause the electrical waves in the wire to reinforce each other.

Building off of this idea, Tesla thought it possible to send large amounts of power to practically any point on the Earth.

The Hypothesis
How would this be done? The basic idea is very simple: one only needs to replace the single wire described above with the Earth, and the Earth would conduct the electrical current from one Coil to the other. But as my father once told me, nothing is ever simple. Here are the issues:


 * The Earth isn't the best conductor of electricity, it is a "dielectric."
 * A large and uneven body like the Earth would provide a lot of resistance, making it even more difficult for power to move through it.
 * One would need an enormous amount of power.
 * To build the transmitter would cost a fortune.

To go into more detail, I will briefly explain a component in electrical engineering, called the waveguide. A waveguide is a hollow tube of metal or dielectric. Pumping electromagnetic waves into this tube will cause the waves to reflect off the insides of the tube and come out the other end. Now imagine, if you will, that the end where the waves would come out is closed; this would cause the waves to reflect off of the closed end and back to their source. And imagine that the distance between the source and the closed end was 1/4 the wavelength; this would cause those reflected waves to be reinforced by the outgoing waves, producing "resonant rise." And imagine that the waveguide is in the shape of a sphere.

So, to summarize the idea, Tesla hypothesized that tuning his transmitting Coil (or a Magnifying Transmitter, a Tesla Coil on steroids) to the resonant frequency of the Earth would cause the waves to reinforce themselves and create a "standing wave" in the Earth. In this way, a resonant coil stuck into the ground would provide anyone with all the power they would ever need. Now, this all looks very nice in theory, but would it actually work? Was it practical? Tesla created a proof-of-concept transmitter in Colorado Springs to answer these questions. Although this transmitter was considerably large, and could create the standing waves he was looking for, it wasn't big enough to do the whole job. However, Tesla did claim to have created an enormous lightning storm once he finally found the right frequency - supposedly, the sparks created were even larger and louder than natural lightning.

Doubts and Uncertanties
Obviously, these claims are very debatable. From what I know, the physical principals seem fine on paper, but I possess no formal training in physics or electricity of any kind; that is to say, I am completely self-taught. And though personally I think I understand a lot, you should still take my words with a grain of salt. And of course one has to consider the problems imposed by economics, environmental concerns and possible dangers of this project. This would obviously require a dangerously huge amount of power to work.

I am not entirely sure if Tesla intended on using one large transmitter, or a series of large transmitters; the question is whether or not one transmitter would actually be able to send power across the entire globe.

Tesla was a proponent of this idea all the way up till his death; it can be judged from some of his quotes that he was certainly emotionally attached to his idea, therefore losing scientific objectivity. Not to mention, we probably know much more about radio waves and their inherent dangers now than he did.

On a slightly unrelated note, I may be slightly woo-orientated on this subject since I would like to, one day, become an engineer.

Conclusion
For now, I can say with some certainty that the Tesla's idea of wireless power transmission might be plausible, but extremely dangerous. I will be continually adding to this essay as I learn more and think of more to write down. Hopefully this essay will spark conversation and debate on the subject. Please feel free to discuss it on this essay's talk page. I am eager to read what you have to say.