Powering Smart Cities With Wind and Solar Energy

As researchers work on advancements in technologies that harvest solar and wind energy, others are working on technology that can do both. Some of the latest work comes through a collaboration between researchers in the US and China that has produced a device that can harvest energy from both sources simultaneously, technology they said could power the Internet of Things (IoT)-driven smart cities of the future.

Researchers from the Beijing Institute of Nanoenergy and Nanosystems and the Georgia Institute of Technology have developed the hybrid harvester based on triboelectrics, the same effect behind static electricity. The triboelectric effect happens between two materials that repeatedly touch each other and then separate, exchanging electrons and building up a charge.

A triboelectric generator that can harvest energy from multiple sources allows for more consistent energy generation than one source can provide on its own, according to researchers. This type of energy generation is ideal for smart cities of interconnected devices that constantly need energy, a vision that’s quickly becoming a reality with the adoption of the IoT.

Researchers in the US and China have developed a hybrid solar-wind energy harvester based on the triboelectric effect, the same one behind static electricity.
(Source: Beijing Institute of Nanoenergy and Nanosystems)

“To realize the sustainable energy supply in a smart city, it is essential to maximize energy scavenging from the city environments for achieving the self-powered functions of some intelligent devices and sensors,” researchers said in an abstract of a paper published about their research in the journal, ACS Nano. “This research presents a feasible approach to maximize solar and wind energies scavenging from the city environments with the aim to realize some self-powered functions in smart cities.”

Shuhua Wang, Xue Wang, Zhong Lin Wang, and Ya Yang Here -- all researchers at the National Center for Nanoscience and Technology at the Beijing Institute of Nanoenergy and Nanosystems -- co-authored the paper. Zhong Lin Wang also is a researcher at the School of Materials Science and Engineering at Georgia Tech.

The team designed a hybrid nanogenerator that includes both a silicon-based solar cell and a triboelectric nanogenerator (TENG) comprised of thin sheets of plastic and Teflon, which are separated by air. The hybrid device generates triboelectricity when wind blows on it, causing the plastic film to vibrate toward and away from the Teflon.

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The device leaves a small footprint, as it's only about 120-mm long, 22-mm wide, and 4-mm deep. Researchers envision the devices installed on the roofs of city buildings to harvest energy.

In tests the solar cell delivered a maximum output power of about 8 mW, while the output power of the TENG delivered up to 26 mW, researchers said. “Impedance matching between the SC and TENG has been achieved by using a transformer to decrease the impedance of the TENG,” they wrote. “The hybridized nanogenerator has a larger output current and better charging performance than that of the individual SC or TENG.”

The new research is from the same team that has developed a window system of smart glass that can harvest energy from wind and rain, which also leverages the triboelectric effect for its functionality.

Elizabeth Montalbano is a freelance writer who has written about technology and culture for more than 15 years. She has lived and worked as a professional journalist in Phoenix, San Francisco, and New York City. In her free time she enjoys surfing, traveling, music, yoga, and cooking. She currently resides in a village on the southwest coast of Portugal.