TINA CASEY
Researchers at Stanford University are on to a new technology that could take the hassle out of charging an electric vehicle. Based on magnetic fields, the system would enable cars and trucks to charge in motion. Weirdly, at the end of your trip you could end up with more “fuel” in your tank than when you started.
The basic principle behind the system is magnetic resonance. The phenomenon was initially developed into a charging device a few years ago by Marin SoljaÄiÄ, an assistant professor of physics at the Massachusetts Institute of Technology.
SoljaÄiÄ was looking for an efficient way to power up cell phones and other small electronic goods wirelessly, over relatively short distances. The path he pursued was resonant coupling, which refers to the interaction between two objects that are tuned to the same frequency. The objects can exchange energy with each other, but have little effect on other objects.
Where SoljaÄiÄ experimented with a 60-watt light bulb, the Stanford team is looking at slightly larger objects, namely, entire highways.
The Stanford team is headed by Shanhui Fan, an associate professor of electrical engineering, who envisions revamping basically the entire national infrastructure so that “you’ll be able to drive onto any highway and charge your car.”
Mark Shwartz of the Precourt Institute for Energy at Stanford University explains:
“Here’s how the system would work: A series of coils connected to an electric current would be embedded in the highway. Receiving coils attached to the bottom of the car would resonate as the vehicle speeds along, creating magnetic fields that continuously transfer electricity to charge the battery.”
So far, the research is in the computer modeling stage. According to Shwartz, the team is working on a system that transmits a charge wirelessly over a distance of about 6.5 feet, which would enable vehicles to maintain highway speed. Anything over that would require a boost from the battery, so it seems that an unintended consequence of the system would be to inhibit speeding (at least among electric vehicle owners).
As for the practicality of ripping up every major road in the U.S. to install arrays of electric coils, that’s not as far-fetched as it may seem given the frequency with which highways are ripped up for routine resurfacing and repairs.
The other big obstacle, of course, would be finding enough electricity to keep the coils charged.
However, given that Stanford’s research hasn’t even gotten to the lab test stage yet, there is plenty of time for the national energy grid to play catch-up.
That doesn’t necessarily mean more mining and drilling. Solar and wind power investment is growing, and the U.S. has other significant renewable energy resources as well, namely hydropower and geothermal.
A pair of Department of Energy studies on ocean and tidal stream hydropower show those sources could account for up to 15% of the U.S. energy supply, and the Department of Defense has estimated that the geothermal potential on its property alone would be enough to power its facilities with some left over for the national grid.
Now, all we need is a new advance in driverless car technology to go with our electric highways, and we’re on our way to a truly hassle-free road trip.
