The kinetic energy of falling water has been turned into electricity since the 1870s
A single raindrop can now power 100 small LED light bulbs, creating a new benchmark for energy-harvesting technologies, scientists have reported.
A research team led by scientists from the City University of Hong Kong (CityU) has recently developed a droplet-based electricity generator (DEG), featured with a field-effect transistor (FET)-like structure that allows for high energy-conversion efficiency and instantaneous power density increased by thousands of times compared to its counterparts without FET-like structure, reports Sci Tech Daily.
The research was led by Professor Wang Zuankai from the department of mechanical engineering at City University, Professor Zeng Xiaoqing from the University of Nebraska Lincoln, and Professor Wang Zhonglin, founding director and chief scientist of the Beijing Institute of Nanoscience and Nanomedicine at the Chinese Academy of Sciences.
Their results were published in the latest issue of the scientific journal Nature titled – “A droplet-based electricity generator with high instantaneous power density.”
The kinetic energy of falling water has been turned into electricity since the 1870s. Current hydropower systems depend, however, on rain falling at high altitudes and collecting together into rivers to reach masses large enough to make turbine harvesting efficient, reports IFL Science.
A new technology seeks instead to use the energy of the falling drops directly, making it useable wherever it rains.
"The kinetic energy entailed in falling water is due to gravity and can be regarded as free and renewable,” said Professor Wang Zuankai of the City University of Hong Kong in a statement. "It should be better utilized.”
The scientists demonstrated the generator’s potential power by dripping water drops onto a polytetrafluoroethylene film over an indium tin oxide substrate. The water spreads across the film and connects aluminum electrodes. This is what makes the charges built up in the film flow as electricity, reports Interesting Engineering.
“Our research shows that a drop of 100 microlitres [1 microlitre = one-millionth litre] of water released from a height of 15cm can generate a voltage of over 140V,” Professor Wang Zuankai said.
The best part is that the scientists have calculated that they are converting 2.2% of each drop’s kinetic energy into electricity. This means that this new improvement might be the tip of the iceberg
