Researchers at the National University of Singapore have developed a compact electricity generation method that produces power from small volumes of falling water – including rain or rooftop runoff – without any moving parts. According to a study published in ACS Central Science, the system achieved a conversion efficiency of 10,4% and could power low-energy devices using only gravity and ambient water sources.
The method uses “plug flow”, a segmented pattern of falling water and air, inside narrow fluoropolymer tubes. As water plugs slide down the tube walls, they generate surface charge that can be captured via external electrodes. The research team reports that the plug-flow setup outperformed other flow types, including continuous, dripping and rivulet flow, with flow pattern alone accounting for efficiency differences of several orders of magnitude.
In a demonstration, four tubes powered 12 LED lights for 20 seconds using just 50 millilitres of water stored in a capacitor bank.
