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Utah researchers experiment with electric roads to charge electric cars

LOGAN — Electric vehicles have long been touted as the answer for drivers who want to avoid high gas prices and help protect the environment. But the heavy, short-lived batteries are a big obstacle to the vehicles becoming affordable and commonplace.

Suppose an electric vehicle could just go on and on, without stopping to recharge batteries. Suppose it was continually charging as it drove along the highway.

A technical breakthrough at Utah State University could make that happen. The idea is to make the highways themselves a source of energy.

"I definitely think it's going to happen," said Hunter Wu, electric engineer at Energy Dynamics Laboratory.

As a visual metaphor of the highway of the future, consider the old hobby of slot-car racing. The electric toy cars don't need batteries. They get their power directly from the track by dragging an electrical contact in a power slot that runs the length of the raceway.

But what if the electricity could literally jump from the highway to the car? USU researchers have managed to get 5 kilowatts of electricity to jump up to 10 inches with 90 percent efficiency. That's easily enough to light up two-dozen light bulbs.

"If we have an infrastructure on the roads to power electric vehicles, then we don't have to carry that power in the vehicle itself," Paul Israelsen, deputy director at Energy Dynamics Laboratory, said.

To demonstrate the concept, USU researchers set an electrical coil or pad on the floor. Plastic cylinders on top of the pad are used as spacers to create the 10-inch gap. A receiving pad goes on top of the cylinders. Electric current in the lower pad creates a magnetic field that bridges the gap.

"So this magnetic field is basically jumping from this bottom pad to this top pad," Wu said.

In the upper pad, the magnetism induces a current that lights up the bulbs. The principle has been in use for decades, but USU researchers claim the highest efficiency yet.

"And also to achieve an air-gap of up to 10 inches, that is quite remarkable," Wu said.

This summer they'll place the upper pad on the bottom of an electric vehicle and test it by driving onto a stationery charging pad.

"We're getting efficiencies that are comparable to the same efficiency you would get with a plug-in electric charger," Israelsen said.

The next hurdle is to get the technology to work with a moving electric vehicle at, say, 70 mph.

If transmitting coils were placed under the pavement every few feet or so, an electric vehicle could, in theory, operate much like a slot car, drawing power from the pavement and traveling many miles without stopping to recharge.

"What this technology, when it's placed inside the road, allows us to do is significantly reduce battery size by up to 80 percent," Wu explained. That would bring down the cost of electric vehicles substantially and make them competitive with gas-powered vehicles.

"We believe it's doable," Israelsen said. "It's going to take a year or two of some science, and some work to get it done, and some funding from some different sources, but we think it can be done."

Of course, the question is would it be done.

Would we ever invest the money to electrify highways and abandon gas engines? It's not a scientific question.

Israelsen said those economic and social issues are much bigger and tougher to solve than the technical issues.

"It's going to take a concerted effort for someone like the president or Congress to stand up and say we need to put some significant infrastructure in place to help electric vehicles move forward," Israelsen said.

He believes it may take a decade or two, but it will happen.