To make it all happen, every "powered roadway" would need a very heavy cable running alongside it to carry huge the amounts of current needed for long stretches of roadway.
Intermittent sections of road would also have to be replaced with pre-fab concrete slabs containing the coils. And the slabs would need incorporation of connecting cables and power electronics to resonate the embedded coils. Stanford currently has three separate engineering departments -- mechanical, electrical, and civil -- working on various parts of the concept.
"Obviously, you would need to dig up the road," Beiker told us. "You'd need a ditch alongside the road for the cables, and you'd need to put the coils into the roadway itself. But all of the technology needed to do this is easily available."
Researchers say that the wireless transmission of power would not be dangerous for people standing between the coils or sitting in passing cars. Transmission of power only occurs between the resonating coils, they say.
To be sure, automakers would need to buy into the plan. Each electric vehicle would need an onboard copper coil measuring about a foot in diameter. The cost of the coil, however, would be small compared to the cost of the huge batteries that electric vehicles now employ.
Beiker contends that the technology would obviate the need for big lithium-ion battery packs. If main streets were equipped with the coils, electric cars would need only enough battery power to go from the smaller arteries to the main avenues. Expensive battery packs weighing 400lb to 800lb would no longer be necessary, and range anxiety would disappear, they say.
"The question is, do we really need batteries that are big enough to take us 300 or 400 miles?" Bieker asked. "You end up with a very heavy battery pack that you don't use most of the time. From an efficiency standpoint, do you really need an 800lb battery pack to drive to the store to get some bagels?"