Kinetic Energy: Could roads recharge electric cars?

EVs are getting a boost, though: They are prominently featured in a $7.5 billion initiative from the Biden Administration, signed by the president earlier this month, with the goal of building a nationwide network of a 500,000 high-speed electric vehicle charging stations by 2030. (Currently, there are about 43,000 charging stations, according to the U.S. Department of Energy.)

But that would solve only part of the problem, in part because charging times are still lengthy. The real sweeping change in the next decade may address that: roadways that electrically power cars as they travel, using a technology known as inductive charging.

In July, the Indiana Department of Transportation and Purdue University announced plans to develop the world’s first contactless wireless-charging concrete pavement highway segment.

The project is being undertaken by an engineering research center called Advancing Sustainability Through Powered Infrastructure for Roadway Electrification (ASPIRE). It is funded by the National Science Foundation.

“One of the major barriers to electrification is the range anxiety. This technology is intended to solve the problem,” said Nadia Gkritza, a professor at the Lyles School of Civil Engineering and ASPIRE campus director at Purdue University. “In simple terms, the vision is to bring the charge to the vehicles, rather than having the vehicle stop at charging stations to recharge.”

The multiyear project will use a magnetisable concrete technology — developed by the German company Magment — enabling wireless charging of electric vehicles as they drive.

The technology works by adding small particles of recycled ferrite — a ceramic made by mixing iron oxide blended with slivers of metallic elements, such as nickel and zinc — to a concrete mixture which is magnetised by running an electrical current. This creates a magnetic field that transmits power wirelessly to the vehicle.

A plate or box made of the patented material, roughly 12-feet long by 4-feet wide, is buried inside the roadway at a depth of a few inches. The box contains coils of wire that connect to the power grid through specialised electronic equipment — that’s the transmitter, explained Dionysios Aliprantis, a professor at the Elmore Family School of Electrical and Computer Engineering at Purdue.

Surrounding the transmitter is normal roadway material — concrete or asphalt. The transmitters would be embedded in the roadway one after the other, allowing for a continuous power transfer. The receiver is a similar, but smaller box with coils that is attached to the underside of a car.

Within the next two years, once the technology is validated in the lab tests, the Indiana Department of Transportation will build a quarter mile-long test bed where engineers will examine the electrified roadway’s capacity to deliver high power to trucks. “We want to take it slowly, to do those test beds and pilots,” Gkritza said. Cost estimates to electrify roads in both directions vary widely, from $1.1 million to $2.8 million per kilometer, according to projections made in the last three years.

“We see this technology as a great opportunity to align with the vision from the U.S. Department of Transportation and the Federal Highway Administration of alternative fuel corridors along major national roadways that support plug-in electric vehicle charging, hydrogen, propane, and natural gas refuelling with existing or planned infrastructure,” Gkritza said. “We are not proposing that all roads will be 100 percent electrified.”