July 15, 2016

IE Questions: Why don’t we have wireless electricity?

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Why don’t we have wireless electricity?

This question comes from many members of our audience: Wouldn’t it be great if we could do away with the vast network of wires, big and small, that connect the electronic devices that run our world to the power plants that generate electricity?

In reality, we do have wireless electricity. But it’s limited. For now, at least, it’s only commercially viable over short distances (think milimeters to meters). Before we get to that, let’s go back in time more than a hundred years, to a man with a dream of worldwide wireless transmission of electricity: Nikola Tesla.

There’s a long list of technology attributed to Tesla and his research: radio, X-rays, remote controls, electric motors, to name a few. But one of his greatest ambitions has never been fulfilled: transmitting electricity around the world without wires.

His first experiments revolved around sending electricity through airwaves. But these experiments could only send power a short distance. Then Tesla got an idea: would the connection be stronger if he went through the ground instead of the air?

Here was his basic theory: send electricity deep into the ground and use the Earth like a giant conductor. Electricity could move for hundreds of miles uninterrupted, and anyone with a receiver could access it, Tesla theorized.

“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. This equipment will be carried in a satchel not as big as the ordinary suitcase. In years to come wireless lights will be as common on the farms as ordinary electric lights are nowadays in our cities.” (Nikola Tesla, The American Magazine, April 1921)

Tesla moved his experiments to Colorado Springs, Colorado in 1899. According to Tesla’s lab notes, he succeeded in sending electricity from his lab to lightbulbs sitting on the ground hundreds of feet away.

But Tesla wanted to go bigger. He started building Wardenclyffe Tower in 1901 on Long Island. Wardenclyffe was to be center of a slough of experiments in transmitting wireless radio and telegraph signals — and sending wireless electricity. Tesla planned that the 17-story tower would send electricity from a coal-fired generator into the ground through 300 feet of metal rods, where the current would travel for hundreds of miles.

To this day, no one is sure that Tesla’s plan would have worked, said Marc Seifer, author of Wizard: The Life and Times of Nikola Tesla. Tesla’s business partner, J.P. Morgan, backed out of the Wardenclyffe project. Tesla eventually went bankrupt and Wardenclyffe was torn down in 1917. His idea of using the ground to send electricity long distances hasn’t been thoroughly tested, and electrical engineers are skeptical it would work, Seifer added.

But Tesla’s research influenced the ways we send electricity without wires today

Since Tesla’s day, we’ve known that it’s possible to wirelessly send electricity through magnetic induction. Or, to be precise, to use a magnetic field to generate an electric current. You already use this type of charging if you have an electric toothbrush.

And Tesla’s dream of worldwide wireless energy is still alive. Japan’s space agency is developing a solar-satellite that would beam power back to earth with microwaves. Their goal for completing the first orbiting solar power plant? 2031 – just in time for Tesla’s 175th birthday.