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Harvesting energy… from car tires?

We've come a long way since the first cars trundled onto our roads.

Today, the vehicles we drive are equipped with everything from satellite navigation and automated parking technology to heated seats and hybrid engines.

But now, engineers at the University of Wisconsin-Madison have come up with technology that enables energy to be harvested from moving tires.

Using a nanogenerator – a tiny device that's able to generate energy from physical movement - the research could enable cars to become more efficient and greener.

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"There are many types of mechanical energy out there," Xudong Wang, an associate professor of materials science and engineering, told CNBC in a phone interview.

The system developed by Wang and his colleagues harnesses the triboelectric effect, which he described as a "common phenomenon in our everyday life."

The triboelectric effect happens when two different objects rub together or come into contact with one another to generate an electric charge.

"Our general concept for mechanical energy harvesting is trying to scavenge (and) recycle the energy that, right now… (is being) wasted anyway," Wang added.

"So, no matter what kind of efficiency we get, it's a net gain… (but) of course we're still looking for improvements (in) efficiency."

In the nanogenerator developed in Wisconsin – in conjunction with a collaborator in China – an electrode is placed in a part of the tire. When in contact with the ground, an electrical charge is generated as a result of friction between the two surfaces.

The findings were reported in a paper published in May in the journal Nano Energy.

According to a release from the University of Wisconsin-Madison, a toy car with LED lights was used in a trial to demonstrate the concept. With an electrical conductor attached to the car's wheels, the lights were able to flash.

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The release added that, "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."

Wang and his colleagues are not alone in their pursuit of energy via tires. Earlier this year Goodyear unveiled a concept tire at the Geneva Motor Show.

According to a video released by Goodyear, the tire is designed to produce electricity using a thermoelectric material that turns heat into electricity, and by using a piezoelectric material – a material that can generate an electrical charge when it is stretched or put under stress.

In terms of an environmental impact, there is solid potential of the research being conducted by Wang and his colleagues.

"It definitely can reduce the fuel consumption and improve the mileage, not by a lot, but by… 2 miles per gallon… something like this," Wang said.

Wang added that scaling up the technology poses its own challenges, especially about integrating the electrodes into a bigger car's tires.

"I think that, right now, it's a concept, but it's promising and I'm very positive (about) this technology's potential," he said.

By Anmar Frangoul, Special to CNBC.com; follow him on Twitter @AnmarFrangoul