brisk walk on a beach

Tiny wind turbine generates energy during a brisk walk

Image credit: Dreamstime

A “tiny wind turbine” that can scavenge wind energy from breezes created by activity as gentle as a brisk walk has been developed by Chinese researchers.

The method is touted as a low-cost and efficient way of using light breezes as a micro-energy source.

The new device takes the form of a nanogenerator made of two plastic strips in a tube that flutter or clap together when there is airflow.

Like rubbing a balloon on your hair, the two plastics become electrically charged after being separated from contact, a phenomenon called the triboelectric effect. The electricity generated by the two plastic strips is then captured and stored.

“You can collect all the breeze in your everyday life,” said senior author Ya Yang of Beijing Institute of Nanoenergy and Nanosystems. “We once placed our nanogenerator on a person’s arm, and a swinging arm’s airflow was enough to generate power.”

A breeze as gentle as 3.6 mph was enough to power the triboelectric nanogenerator, although it performs at its best when wind velocity is between 8.9 to 17.9 mph, a speed that allows the two plastic strips to flutter in sync.

The device also has a high wind-to-energy conversion efficiency of 3.23 per cent, a value that the researchers say exceeds previously reported performances for wind-energy scavenging. Currently, the device can power up 100 LED lights and temperature sensors.

“Our intention isn’t to replace existing wind power generation technology. Our goal is to solve the issues that the traditional wind turbines can’t solve,” Yang said. “Unlike wind turbines that use coils and magnets, where the costs are fixed, we can pick and choose low-cost materials for our device. Our device can also be safely applied to nature reserves or cities because it doesn’t have the rotating structures.”

The team eventually wants to designed a compact nanogenerator capable of providing power to small electronic devices such as phones.

Yang is also looking to make the device bigger and more powerful. “I’m hoping to scale up the device to produce 1,000 Watts, so it’s competitive with traditional wind turbines,” he said. “We can place these devices where traditional wind turbines can’t reach. We can put it in the mountains or on the top of buildings for sustainable energy.”

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