Txchnologist: Coast To Coast On Electric Roads Without Stopping?

Korea Advanced Institute of Science and Technology electric road trial; photo courtesy KAIST

Korea Advanced Institute of Science and Technology electric road trial; photo courtesy KAIST

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We ask a lot of our cars: Heat me, cool me, be silent, be comfy, be exciting, and, increasingly, propel me without costly and polluting gasoline.

It’s the latter request that confounds, since batteries, the most obvious replacements for gas, are heavy and have limited energy storage.

But what if the energy storage burden was shifted from our overworked cars to the road?

Researchers at the Energy Dynamics Laboratory at Utah State University are working on just such a solution, called electrified roads.

Electric vehicles, or EVs, could pick up small amounts of electricity as they drive over charging pads buried under the asphalt and connected to the electrical grid. Researchers say that a continuously available power supply would allow EVs to cut battery size as much as 80 percent, drastically reducing vehicle cost.

“Basically you get power directly from the grid to the motors as the car moves,” said Hunter Wu, a Utah State researcher recruited from the University of Auckland in New Zealand, where the technology was pioneered, to further develop the concept.

Scenes from dedication of electric-car charging station at Creekside Inn, Palo Alto, CA

Scenes from dedication of electric-car charging station at Creekside Inn, Palo Alto, CA

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“You can travel from the West Coast to the East Coast continuously without charging.”

Nicola Tesla first proposed wireless energy transfer more than a century ago. He first discovered the principles of wireless charging, or inductive power transfer, in the late 19th Century. It works by creating an electromagnetic charging field that transfers energy to a receiving pad set to the same frequency.

Manufacturers are already marketing wireless charging pads for electric vehicles--retrofitted to accept the charges--that can deliver a 5-kilowatt charge with 90 percent efficiency from a distance of about 10 inches.

There is also a trial application of electric roads just for buses, albeit at slow speeds and using very long charging pads, at the Korea Advanced Institute of Science and Technology, outside Seoul.

But Wu is thinking of something much more radical: charging at Interstate speeds. This will require several technical breakthroughs, he said.

“At 75 mph, you’re only going to stay on a pad for about 30 milliseconds,” he said. “We need to turn the pad embedded in the road on and off really quickly.”

The pads would need to be able to signal to each other that a car is coming, he said, and the car would also need to communicate its need for a charge.

2011 Nissan Leaf at quick-charging station

2011 Nissan Leaf at quick-charging station

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Wu said the pad must also deliver power even when the car isn’t directly on top of it. That's a capability called horizontal misalignment that the today's stationary inductive power transfer chargers don’t have.

John Boys, a University of Auckland professor who is credited with refining the technology, said it would be possible to transfer up to 30 kilowatts of power at an average efficiency of 80 percent on the highway.

Assuming that chargers would be available at home and work, Boys said, a car would only need “a battery big enough to make it to the nearest interstate or major road.”

Wu said the cost of electrified roads, pegged at $1.5 million to 2.5 million per lane-mile, could be made up through charging a toll along the roadway.

Not only the cost of electric cars, but also range anxiety would be totally eliminated, he said.

“This technology,” Wu said, “would propel electric cars forward.”

This article was repurposed with permission from Txchnologist.com, an online magazine presented by General Electric. High Gear Media's editors have edited the article to conform to this site's standard formats.

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Comments (11)
  1. I'm speechless in the face of this one. Sorry.

  2. 1.5 million for 1 mile of road? REALLLYLLYLY? THAT'S A LITTLE MUCH...

  3. That kind of money for a road, when we could waste it fighting endless wars? Ridiculous. Think of the city of New York having these streets. Thinks of the energy created by people just walking the streets.

  4. #2 Lucjan Wilczek - I think it's actually $1.5 million per lane mile. So for a freeway with 4 lanes in each direction that's $12 million a mile if you do all the lanes. And if you only did one lane in each direction (does that work?) it's at least $3 million. Cheap compared to a new freeway or a rail line, but it adds up pretty fast, LOL.
    #3 almxx - Amen on the wars, BTW. It's almost scary to think what we could do with all that wasted money.

  5. What a joke. I can just imagine this brainless country spending ten national debts to build these silly roads, just in time for a practical battery to come along and render them totally obsolete.

  6. wow, if true then I would really love to step on the road.

  7. gosh, i think it is the next big step in our road system. it has a lot more to it than just charging our cars.
    click on my name to look at solar roadways.

  8. ev enthusiast: clicked on your name and found the report very interesting. I watched several videos and found myself wishing this could come to pass. I think it would be a much simpler way to power our homes and businesses and provide power to charge our new electric car future.

  9. Better Place model is much more feasible economically. at less than 5 minutes to swap batteries, its a no brainer. add to that grid management, storage and demand leveling. its the way to go. too bad it will probably take a decade for private companies to build the grid without help

  10. The technology will be reversed, whereby the vehicle will be self powered and self charged with various kinetic motions of the vehicle. By using these forces, you turn all the vehicles on Earth into mini power cells that contribute more power - not by taking power from the grid with excess power generated on board. Wireless uploads stations will be placed like cell towers around the roads to receive power or stored in super capacitors to plug in later for home power use. This changes the game totally, like putting a fuel cell in the home, you have no dependency on the grid or ancient technology to receive power from afar+self charge with unlimited range.

    For more information;


  11. so, two million dollars per mile. Versus one million dollars per 75 miles of a battery-swap station. Now that makes sense. Or does it?

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