New floating generator makes electricity from falling raindrops

Chinese researchers at Nanjing University of Aeronautics and Astronautics have developed a novel floating hydrovoltaic generator, called the water-integrated droplet electricity generator (W-DEG), that converts the kinetic energy of falling raindrops directly into electricity while floating on water surfaces. Unlike traditional droplet electricity generators that rely on rigid, land-based metal electrodes and heavy materials, the W-DEG uses natural water as both the structural substrate and conductive electrode. This design reduces material weight by about 80% and cuts costs nearly in half, while producing voltages around 250 volts per droplet—comparable to conventional devices. The water’s incompressibility and surface tension provide mechanical support for raindrop impacts, and ions in the water act as stable charge carriers. The W-DEG demonstrates strong durability and environmental resilience, maintaining stable operation under varying temperatures, salt concentrations, and biofouling conditions due to its chemically inert dielectric layer and water-based structure. A self-reg