Stanford University researchers may have come up with the idea of making an electric car highway in which magnetic fields could transmit electrical currents on highways, charging cars as they are driven.
The study was published in the journal 'Applied Physics Letters'. Shanhui Fan, an electrical engineer at Stanford and a co-author of the paper told Huffington Post that, Our vision is that you'll be able to drive onto any highway and charge your car.
What makes this concept exciting is that you could potentially drive for an unlimited amount of time without having to recharge, said Richard Sassoon, managing director of the Stanford Global Climate and Energy Project and a co-author of the study.
You could actually have more energy stored in your battery at the end of your trip than you started with, Sassoon added.
Wireless transfer of electrical charge is not new to us. In the 19th century, Nikola Tesla had designed a 187-foot tower that could transmit electricity to points miles away. But due to meagre funds and industrial use and dependence on wiring, the project never took off.
In 2007, a researcher at the Massachusetts Institute of Technology figured out a way to light a 60-watt bulb using a technology known as magnetic resonance coupling.
The present theory of the electric highway is based on this: Two metal coils are set apart at a distance and are tuned to resonate at the same frequency. One of the coils is connected to an electrical source, which creates a magnetic field that makes the other coil start to resonate. This results in the invisible transfer of electricity through the air from the first coil to the second.
Wireless power transfer will only occur if the two resonators are in tune, Fan said. Objects tuned at different frequencies will not be affected.
The next question before the Stanford researchers was how to put the coils in a highway so that they can be used as the most effective and directed form of energy.
Two Stanford postdoctoral students came up with the solution: A coil bent at 90 degrees and attached to a metal plate can transfer 10 kilowatts of electrical energy to an identical coil 6.5 feet away.
That's fast enough to maintain a constant speed, Shanhui Fan said. To actually charge the car battery would require arrays of coils embedded in the road. This wireless transfer scheme has an efficiency of 97 percent, explained Fan.
Check out the video of the Stanford University research team here.