The promising new system is 80% lighter and significantly cheaper than current devices that already convert rain into energy.
Chinese researchers have developed an innovative floating generator that converts energy from raindrops directly into electricity — a step towards a new class of renewable “hydrovoltaic” technologies that do not require land or heavy infrastructure.
The water-integrated droplet electricity generator floats on the water and uses the water itself as part of its electrical and structural system. , published in the National Science Review, describes a lightweight and low-cost design which can be put into practice in lakes or reservoirs and in coastal environments using only rainwater.
Traditional droplet electricity generators rely on solid substrates and metal electrodes to create a voltage when raindrops hit a surface. Although effective, these devices are generally heavy, expensive and restricted to onshore installations, explains .
The new floating W-DEG eliminates these limitations. By allowing water to act as the bottom electrode, the device reduces weight by around 80% and costs by almost half compared to current systems. When raindrops hit its dielectric film, the surface tension and incompressibility of water absorb impact and spread drops evenly. The ions in the water then carry electrical charges, allowing the system to produce voltages of around 250 volts per drop — comparable to rigid metal-based designs.
“This project allows the water itself to serve both as support and electrodecreating a simple, scalable and sustainable approach to droplet power generation,” said principal investigator Wanlin Guo, who led the project.
Tests showed that W-DEG continued to generate power under different temperatures, salt concentrations and even in biofouling natural waters, thanks to its chemically stable dielectric layer. To maintain efficiency during heavy rain, the team added micro drainage holes that allow excess water to drain without interrupting the impact of the drops.
In a demonstration, a 0.3 square meter prototype powered 50 LEDs simultaneously and charged capacitors in a few minutes. Researchers say the system could, one day, provide clean, grid-independent electricity for environmental monitoring or for small local power grids in regions with frequent rainfall.
