‘Nanogenerator’ harvests power from rolling tires

Madison, Wisconsin – A team of engineers at the University of Wisconsin-Madison (UW-Madison) have developed a device that harvests energy from a car's rolling tire friction.

The ‘nanogenerator’ device relies on “the triboelectric effect” to harness energy from the changing electric potential between the pavement and a vehicle's wheels, said a 29 June press release,

Xudong Wang an associate professor of materials science and engineering at UW-Madison and his PhD student Yanchao Mao have been working on the project for about a year,

The nanogenerator relies on an electrode integrated into a segment of the tire. When this part of the tire surface comes into contact with the ground, the friction between those two surfaces ultimately produces an electrical charge-a type of contact electrification known as the triboelectric effect.

They attached an electrode to the wheels of the car, and as it rolled across the ground, the LED lights flashed on and off. The movement of electrons caused by friction was able to generate enough energy to power the lights, supporting the idea that energy lost to friction can actually be collected and reused.

The researchers also determined that the amount of energy harnessed is directly related to the weight of a car, as well as its speed.

According to Wang, a 10-percent increase in the average vehicle's gas mileage can be achieved at a 50-percent friction energy conversion efficiency rate.