It produces infinite energy with raindrops

It produces infinite energy with raindrops

Imagine solar panels that also work without the sun, literally capturing energy from raindrops. Chinese scientists believe they’ve made this breakthrough with photovoltaic panels, which work when the sun is shining as normal but also continue to harvest energy at night and under cloud cover. Although the application is still some years off, it’s an exciting development in solar energy technology as it means that the power supply won’t plummet when direct sunlight is unavailable.

Solar innovation means energy can be harvested from raindrops and sunlight

In many parts of the globe, solar energy has become the cheapest form of power, and this is due to technology developing while costs have dropped 10% of what they used to be. But no matter where on earth solar panels are installed, it’s just not possible to make the sun shine all the time. This is where the Chinese Soochow University photovoltaic panel project comes in.

Triboelectric effect used to generate energy from movement of raindrops

Triboelectric refers to a charge of electricity generated by friction, and it’s this process that engineers have developed in a hybrid solar cell with a triboelectric nanogenerator (also called a TENG). The concept is that the movement of raindrops on the surface of the panel with maintain an electricity supply when there’s no sunlight to sustain it.

The device in development at Soochow University involves the placement of two transparent polymer sheets onto a solar PV (photovoltaic) cell placed at an angle. The theory is the movement of raindrops rolling off will generate a static electrical charge.

Baoquan Sun, one of the scientists working on the hybrid solar cells at the university, explained:

“Due to our unique device design, it becomes a lightweight device. In future, we are exploring integrating these into mobile and flexible devices, such as electronic clothes. However, the output power efficiency needs to be further improved before practical application.”

Sun said the field is developing so fast that he expects a prototype model to be released in three to five years.

Experts in the solar field evaluate new photovoltaic technology

Varun Sivaram of the US Council on Foreign Relations, who has also written an in-depth book on solar power, says the idea of a hybrid device that harvests kinetic energy from water without affecting the output of the solar cell when sunlight is available is an interesting concept. He also extolled the engineering aspect, saying:

“There’s lots of nice engineering, like using one layer to do double duty as a component of the Teng as well as trap light for the solar cell.”

However, he believes that the power output generated from rain needs to be a lot higher to make a difference to the generation capacity, and he’s not confident that this project will have any significant impact on the field of solar energy.

Prof Keith Barnham of the Imperial College, London, says the new Chinese system offers the advantages of being more efficient and compact, but when it comes to the generation of triboelectric energy, there’s a better way:

“Wind power is clearly the most effective and complementary power source to PV – and it works equally well in the rain.”

Practical applications of new TENG technology

To explain simply, triboelectric nanogenerators (TENGs) generate a charge through the friction of two materials moving against each other, which is commonly called static electricity. The technology could be applied to touchscreens, for example, where just the friction of your fingers on the screen could charge the battery. The vibrations of cars on the roads or people walking could be converted into electrical power.

Experts in the world of solar energy aren’t exactly jumping up and down in excitement about the TENGs the Chinese are working on, and the main reason for this appears to be the low power output that’s plausibly able to be generated from the raindrop system. But, as with many scientific innovations, the technology may branch out in a new, more practical direction.

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