Wireless Electricity Not Far-Fetched

By Craig Taylor

Published in the Fall 2009 issue of MyTekLife Magazine

For over a century now, engineers and scientists from all over the world have known that transferring electricity without wires can be accomplished. Believe it or not, it all started with one of America’s most respected inventors and electrical engineers, Nikola Tesla, back in 1899.

Tesla worked on over 760 patented inventions and is credited for developing the alternating electrical current, which eventually surpassed Thomas Edison’s direct current system and became the standard in the United States. In 1899, he accomplished an incredible technological breakthrough in Colorado Springs, Colo. He successfully transmitted 100 million volts of high-frequency electrical power wirelessly over a distance of 25 miles. The power transmitted lit up 200 bulbs and also ran one electric motor.

In 1901, he convinced a prominent investor to construct a tower in Long Island, New York. It was to be the first tower to transmit electrical energy without wires to the whole world. His plan was to utilize the Earth’s ionosphere. The ionosphere is the ionic charged part of our atmosphere, which protects us from solar radiation. It is also a place where atoms and molecules are torn by solar radiation, and it is an excellent conductor of radio waves, as well. Unfortunately, for unknown reasons, the investor that pledged support for this endeavor withdrew his funding, and Tesla was forced to abandon the project.

The tower was torn down and demolished in 1917. Over the next two decades, other inventors introduced similar devices and various methods for transmitting electrical energy without wires. After the Second World War, all efforts on the subject were halted. Later, scientists pursued transferring energy using electromagnetic radiation, but it proved to be inefficient because the waves sent spread in all directions, causing most of the energy to become lost. It was not until the year 2006 that the concept resurfaced by researchers from the Massachusetts Institute of Technology, led by Professor Marin Soljacic.

An experiment was conducted, which consisted of using two copper coils, a transmitter attached to a power source and a receiver attached to a lightbulb that was placed seven feet from the transmitter. The lightbulb was successfully lit without any wires. The data gathered by the initial experiment indicated that 40 percent of electricity was transferred to the lightbulb. What was interesting about this is that when wood, metal and other devices were placed between the two coils, the energy still traveled to its destination despite these obstructions. According to Professor Soljacic, the idea to transmit power wirelessly began late one night several years ago. “It was probably the sixth time that month that I was awakened by my cell phone beeping to let me know that I had forgotten to charge it. It occurred to me that it would be so great if the thing took care of its own charging,” said the professor. He began working on this and soon realized that close-range induction inside a transformer could potentially transfer electricity over long distances. A power transmitter would fill the space around it with an electromagnetic field that is “non-radiative,” and energy could then be picked up by devices, exclusively designed to “resonate” with the field. The energy not picked up by a receiver would be reabsorbed by the emitter.

What does this mean for our future? Soljacic envisions a future when laptop computers and mobile devices will no longer need wires at all. Imagine not having any underground or above-ground cables. What about batteries? They would become obsolete, since electricity would be all around us. We could also potentially see vehicles with coils installed, which would replace combustible fuels. The possibilities are immense.