For sustainable society


Droplet-based electricity

Speaking of renewable energy, you might think of solar, wind, tidal, and hydraulic. Although solar power and wind power are major renewable energies, do you know that there is a technology to generate electricity from rainwater?

Until now, rainwater power generation technology has not been able to generate large amounts of electricity with small droplets. However, a research team at the City University of Hong Kong has announced that it may be possible to generate electricity even with a little rain. Professor Wang at the City University of Hong Kong said: “We found that a drop of 100 microliters (1/10,000 liters) of water released from a height of 15cm can generate a voltage of over 140V, which can light up 100 small LED lights.”

Although researches on voltage generation using raindrops have been conducted for many years, generating electricity from raindrops energy has been regarded as more difficult than using energy from tides and river flows. However, the research team at the City University of Hong Kong succeeded in improving the efficiency of energy generation over two years. When a falling water droplet hits on the Poly Tetra Fluoro Ethylene (PTFE) surface, used for Teflon processing of pan, it bridges two electrodes and makes a closed-loop electric circuit. Then, it was found that the stored charges are released to generate electric current. For the results of the research, Professor Wang said: “I hope that the outcome of this research would be helpful to the global problem of renewable energy shortage. I believe that, in the long run, this new discovery could be applied wherever water is in contact with a solid surface.” Although it seems to take a long time to put it to practical use, electricity may be generated from the outside of the hull, the inside of the water bottle, the surface of the umbrella, etc. in the future.


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