Researchers from City University of Hong Kong (CityU) have recently developed a new type of generator that uses rain to create electricity, and it works. The generator produces a high voltage from a single drop of rain: more than 140 volts even when falling from 15cm or higher. This is what it takes to light up 100 small LED bulbs.
The generator uses a field-effect transistor (FET) type of structure that enables high energy conversion efficiency. According to the university press release, in comparison with its counterparts that do not have FET-like structures, its instantaneous power density is increased by thousands of times.
Three professors led the research team: Professor Wang Zuankai (Department of Mechanical Engineering, CityU), Professor Zeng Xiaocheng (University of Nebraska-Lincoln), and Professor Wang Zhonglin (Founding Director and Chief Scientist at the Beijing Institute of Nanoenergy and Nanosystems of Chinese Academy of Sciences).
Professor Wang mentioned that he hoped harvesting energy from water could help to provide more renewable energy around the world for those in need. He believed that in the long run, the new design could be applied and installed on different surfaces, where liquid is in contact with a solid, to fully utilise the low-frequency kinetic energy in water. “This can range from the hull surface of a ferry to the surface of umbrellas or even inside water bottles.” Imagine charging your phone while walking in the rain — from the rain itself. Imagine plugging your phone into your water bottle.
