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Spotted: Hydropower already contributes more than 17 per cent of global electricity generation. But hydropower can currently only be generated in areas with rivers or other bodies of water. But what if electricity could be generated from water that falls from the sky as rain? Researchers at Tsinghua University in China have made a breakthrough that could make this idea a reality.

When raindrops fall from the sky, they produce a small amount of energy, and the research team has developed a device – called a triboelectric nanogenerator (TENG) – that harvests this kinetic energy and turns it into electricity.

The TENG uses liquid-solid contact electrification to harvest energy from waves and other forms of liquid-solid triboelectric power – electric charge generated when objects contact or slide against each other, like with shoes on a carpet. Up to now, however, droplet-based TENG panels were limited in the amount of electricity they could harvest.

In a recently-published paper, the researchers outlined how they managed to overcome this limitation by connecting TENG panels together, in a similar way to solar panel arrays, limiting unintended power loss. The peak power output of the array is around 200 watts per square metre.

“Although D-TENGs have ultra-high instantaneous output power, it is still difficult for a single D-TENG to continuously supply power for megawatt-level electrical equipment. Therefore, it is very important to realise the simultaneous utilisation of multiple D-TENGs,” said Professor Zong Li, of the Tsinghua Shenzhen International Graduate School at Tsinghua University.

Hydropower’s promise of clean, reliable, and sustainable energy has led to a wide number of innovations. In the archive, Springwise has recently spotted developments such as a fluid that makes pumped hydro more affordable and a floating platform for harvesting hydropower from rivers.

Written By: Lisa Magloff