Researchers at the National University of Singapore (NUS) have developed a new method to generate electricity from rain-like water droplets, demonstrating that falling water moving through a vertical tube can produce enough power to light 12 LEDs, according to findings published in ACS Central Science by the American Chemical Society.
Led by Associate Professor Siowling Soh, the team used a flow pattern known as “plug flow,” where rain-sized droplets collide at the top of a 32-centimeter-tall, 2-millimeter-wide polymer tube, creating short columns of water separated by air pockets that enhance charge separation along the tube’s conductive inner surface.
Unlike traditional hydropower, which depends on large rivers and turbines, this system harnesses charge separation from smaller water volumes, converting more than 10 percent of the falling water’s energy into electricity and producing five orders of magnitude more output than continuous water flow under similar conditions.
In experiments, directing droplets through four tubes enabled the setup to continuously power 12 LEDs for 20 seconds, and researchers noted that because the test droplet speeds were slower than natural rainfall, real-world rain could potentially generate even higher outputs.
The study, funded by Singapore’s Ministry of Education, the Agency for Science, Technology and Research (A*STAR), and NUS’s Institute for Health Innovation & Technology, suggests that rooftop rain-harvesting systems could one day complement urban renewable energy infrastructure without the ecological disruption associated with dams.
