New research has identified ways to get power out of raindrops, previously considered a tough source of renewable energy.
According to ScienceAlert, this new method showed it was possible to generate enough power from a single droplet to keep up to 100 LED bulbs running.
“Our research shows that a drop of 100 microlitres of water released from a height of 15 centimetres can generate a voltage of over 140V, and the power generated can light up 100 small LED lights,” says biomedical engineer Wang Zuankai from the City University of Hong Kong (CityU).
The team used a modified droplet-based electricity generator (DEG) which had built-in polytetrafluoroethylene or PTFE film. This film is able to accumulate a surface charge as it’s continuously hit by water droplets, until it gradually reaches saturation.
The team found that as water droplets hit the surface and spread out, the drops act as a ‘bridge’ that connects two electrodes: an aluminium electrode and an indium tin oxide (ITO) electrode.
The droplet bridge creates a closed-loop surface so that all of the collected energy can be released – droplets act as resistors, and the surface coating acts as a capacitor.
This approach could eventually be applied anywhere that water hits a solid surface according to the researchers, including the top of an umbrella.
“The significance of this technology is the much enhanced electric power per falling rain droplet, which makes the device much more efficient to convert energy from a falling droplet to electricity,” chemist Xiao Cheng Zeng, from the University of Nebraska-Lincoln, told Vice.
The researchers hoping to have a prototype ready in the next five years.