Cutting-edge rain energy: Singapore harvests electricity from rain using solar panel principles — and it’s 10x more efficient

This might sound like science fiction, but rain electricity is becoming very real—and much more exciting than it sounds. Let’s dive into what scientists have been up to.

Reimagining rain: electricity from every drop

A team at the National University of Singapore has discovered a way to generate electricity from falling water droplets using a concept that’s surprisingly similar to how solar panels work — but with rain.

“Water that falls through a vertical tube generates a substantial amount of electricity by using a specific pattern of water flow: plug flow,” explains Siowling Soh, lead researcher of the study published in ACS Central Science.

Using a simple setup, water flows out of a tower through a metallic needle, forming droplets that drop into a tube. When these droplets hit the tube head-on, they create a plug flow — a sequence of water columns separated by pockets of air. This setup allowed them to light up 12 LED bulbs using nothing more than falling water.

What makes plug flow so efficient?

The secret lies in the principle of charge separation — “like rubbing a balloon on your skin,” says the team. When water slides over a specially treated surface inside the tube, it either gains or loses charge. This generates electricity without needing massive water flows like a hydroelectric dam.

While typical hydro power requires large rivers and high-pressure systems, this rain energy model works with small, slow-moving water volumes. It’s minimalist, scalable, and incredibly promising — especially for urban environments.

A clean energy future on your rooftop

The team’s setup managed to convert more than 10% of the water’s energy into electricity — a figure that’s already ten times higher than what similar prototypes managed in the past.

The researchers believe this could lead to an affordable, simple, and low-maintenance way to power buildings. Picture a future where every rooftop could double as a miniature rain energy harvester.

Even though the droplets in their test moved slower than natural rain, the scientists are confident: with the right tweaks, this tech could extract more energy during real rainfall.

“This plug flow pattern could allow rain energy to be harvested for generating clean and renewable electricity,” Soh emphasizes.

The next step in clean tech evolution?

While it’s still in early research stages, this technology could complement existing solar or wind systems. Instead of just waiting for the sun, homes could tap into rain energy during cloudy, wet days — solving one of renewable energy’s biggest challenges: reliability during bad weather.

For cities aiming to go greener, this might be the missing piece. And as climate change drives more extreme weather patterns, having flexible, weather-responsive energy systems could make all the difference.

So, the next time it rains, look up. That downpour might not just be watering your garden — it might soon be powering your home.

More details: DOI: 10.1021/acscentsci.4c02110

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But wait — there’s more happening with raindrops

While Singapore uses plug flow tubes, researchers in China are exploring another method: triboelectric nanogenerators (TENGs) — devices that capture energy when raindrops hit a surface.

Solar panel logic, raindrop style

In a study published in iEnergy, a team at Tsinghua University built bridge array generators. These link multiple TENGs together, like a solar panel grid, boosting power output.

“Although D-TENGs have ultra-high instantaneous output, it’s hard for one to power big systems,” said Professor Zong Li.

5x more efficient

Their new design solved a key issue: energy loss from panel interference. With improved materials and layout, they hit 200 watts per square meter — five times more than previous versions.

The takeaway?

Whether it’s plug flow tubes or solar-style raindrop panels, rain energy is no longer just a concept. It’s becoming a global reality — one drop at a time.

Further information on the research can be found in the paper published in iEnergy.