Grassroots technology can generate solar power from rain

Grassroots technology can generate solar power from rain

A new technology may allow to generate solar power, come rain or shine. However, for it to become useful in daily life, there are still some obstacles to overcome. Thus it may still take some years before it becomes fully applicable.

Solar power’s popularity is on the rise: With costs sinking by as much as 90% over the past decade, it has become the most affordable energy type in many countries. However, there is one major disadvantage: the power is generated from sunshine. As a result, noticeably less energy is being converted during rainy and cloudy weather and none at all at night. This is a problem scientists have recently been addressing with different approaches. One is to include perovskite, a mineral, as a material in solar panel design. Others use so-called “quantum dots“ or research artificial photosynthesis. But the most promising idea is a new technology which allows to generate solar energy from raindrops.

New panel developed in China

To make this possible, a new type of solar panel has been developed, which was recently demonstrated in a laboratory at Soochow University in China. The idea is to generate a static electricity charge from the friction that raindrops cause once they fall onto and roll off the surface. To enable this, two transparent polymer layers are placed on the panel. “Our device can always generate electricity in any daytime weather,” said Baoquan Sun, at Soochow University, whose team’s work was published by ACS Nano journal. “In addition, this device even provides electricity at night if there is rain.”

Not a new idea

The Soochow University team are not the first scientists to work on this idea. Similar devices, referred to as triboelectric nanogenerators (Tengs), have previously been created by other researchers, but the new system is simpler and more efficient. In its case, one polymer layer acts as the electrode for both the Teng and the solar cell, making the device lighter. The Chinese team are hoping to use these new lightweight cells not just for solar panels, but also to include them in electronic clothing in the future. However, before this can happen, the output power efficiency needs to be further improved, so another three to five years might be needed before a protoype can be released.

Hybrid devices might be the next step, but experts are cautious

Meanwhile, other scientists in China have tried using Tengs on solar cells to generate power from wind. Grooving the top layer of the Teng might increase its efficiency by focusing more light on the cell. Bearing these thoughts in mind, Sun says that a hybrid device combining both technologies might be an idea for the future.

Experts applaud the approach, such as Varun Sivaram, member of the US Council on Foreign Relations and author of “Taming the Sun: Innovations to Harness Solar Energy and Power the Planet“, who says that “the idea is interesting – a hybrid device that harvests kinetic energy from water without destroying the output of the solar cell during sunny times.” Nonetheless, he is realistic and thinks that the power the device generates from falling rain needs to be significantly higher to start making an overall difference to a solar panel’s output.

Source: The Guardian

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