Besides the death ray and the oscillator that could cause earthquakes, one Nikola Tesla invention still has the power to pique the interest of those fascinated by all things physics, even today: wireless electricity.
By today’s standards, Nicola Tesla was something of a populist. Free electricity was unheard of then, and it’s still unheard of today. And like many of Tesla’s inventions, this one has given rise to a flurry of speculation, extending even to the Tunguska meteor mystery.
Is wireless electricity even possible? And if so, why don’t we have wireless electricity today?
A man ahead of his time
Tesla was truly a man ahead of his time. What he spoke of as free electricity was actually wireless electricity, which would be beamed across the world from towers in every major city. Far-fetched? You might be surprised. He actually managed to design a device that can produce and transmit electricity wirelessly.
The Tesla coil
Tesla’s design resulted in his invention in 1891 of the Tesla coil. The Tesla coil is as simple as it is potentially dangerous. Anyone can make one, as long as they get their hands on some copper wire and glass bottles. Even one of these amateur coils has the ability to produce up to a quarter of a million volts.
The Tesla coil is made up of two coils, a primary and a secondary one, each with its own energy storage, called a capacitor. Between the two coils, there is what’s called a spark gap: a gap of air between two electrodes where the spark of electricity occurs, much like what we’ve seen in movies about the early days of electricity.
As Live Science’s Kelly Dickerson outs it aptly, the Tesla coil is basically a set of two open circuits connected by a spark gap.
Here’s how it works. The primary coil gets connected to a power source—which already makes the electricity produced by the system non-free, but more on that later. The primary coil’s capacitor takes in and stores the charge coming from the power source. Once it reaches a critical level of charge, the capacitor breaks down the air resistance in the spark gap and charge flows out creating a magnetic field.
A million volts
The charge released from the primary coil is strong enough that the magnetic field itself breaks down quickly enough, generating a high-voltage electric current in the secondary coil. The process is called electromagnetic induction. As the magnetic field breaks down, it creates electric potential (voltage) that makes the electrons move. As they move, they, in turn, generate a magnetic field. As this magnetic field flows through a coil of copper wire, it generates voltage and consequently, electric current.
The coils are the really clever part. The fewer the turns of wire on a coil, the lower the voltage. The higher the number of turns—the higher the voltage. So, in Tesla’s coil the primary coil, the one connected to the power generation source, has relatively few turns. The secondary one, however, has many. The voltage goes from 10,000 volts in the primary coil to 100,000 to even 1 million in the secondary coil. This is the potential needed to beam out the electricity through the air.
Every mad scientist has his castle, and the castle of Nicola Tesla—referred to by many as the prototype of the mad scientist character in the first place—was Wardenclyffe Tower.
Tesla began building Wardenclyffe Tower on Long Island in 1901. It was to be both a research facility and a transmission tower for wireless electricity. Here we go back to the free—or non-free as it happens—aspect of the legend.
Tesla planned to generate the electricity in a coal-fired plant and send it across the world using the tower. Only he was not going to use it the way radio and TV towers are used—by transmitting the signal or in this case, the electric current through the air. He planned to use the Earth itself as a giant conductor. To that end, he would lay into the ground 300 feet of metal rods. After leaving the rods, the current would travel for hundreds of miles.
If it sounds far-fetched, imagine how it sounded at the time. And that’s how Tesla himself sounded when he talked about it:
“Power can be, and at no distant date will be, transmitted without wires, for all commercial uses, such as the lighting of homes and the driving of aeroplanes. I have discovered the essential principles, and it only remains to develop them commercially. When this is done, you will be able to go anywhere in the world — to the mountain top overlooking your farm, to the arctic, or to the desert — and set up a little equipment that will give you heat to cook with, and light to read by,” he told The American Magazine in 1921.
Still a mystery
Unfortunately, Wardenclyffe Tower never really went into operation because J. P. Morgan pulled out his funding for Tesla, who later went bankrupt. The tower was demolished in 1917. Yet today there are a couple of scientists who have their eye on building a new one.
Leonid and Sergey Plekhanov, two brothers, both physicists, started a now-closed crowdfunding campaign on Indiegogo that aimed to raise $800,000 to build a new Wardenclyffe Tower. According to them, Nikola Tesla’s wireless electricity idea could really work and send electricity across the world for free.
What’s more, the Plekhanov brothers also said the world’s electricity needs could be met with a giant solar farm somewhere in a desert near the equator. From there, the idea is for the electricity to be beamed wirelessly across the world. We will have to wait for any results, however. The initial campaign only managed to raise $46,998—about 5% of their 800,000 goal. Their second campaign, called the Planetary Energy Transmitter, only raised about $4000 of a $200,000. Sadly for those of you holding out hope for free energy, this campaign has been closed too.
We calculate the brothers raised funds were $100,000 shy of what Tesla received from JP Morgan to construct the tower in the first place, so we suspect for now, that specific project is a no-go.