A group of Japanese researchers from the Toyohashi University of Technology demonstrated a wireless power transmission technology yesterday at the Wireless Technology Park 2012 in Yokohama, Japan. During the demonstration, the team sent 50-60 watts of power through 10cm (3.9 inches) of solid concrete to a modified automobile tire and then on to an incandescent light bulb.
The team's idea is to supplement electric vehicles with power from inductors built into roadways, but Takashi Ohira, who leads the research group, says that nearly 100 times as much electricity would have to be transmitted for it to be effective. While the technique the team used (called inductive coupling) is hardly new, they claim to be getting 80-90 percent efficiency through solid concrete, which is roughly the same as Sony's wireless TV through 50cm of air. It might be quite some time before Japan sees electrified roadways, but this demonstration is certainly a good start.