Scientists and engineers have long been looking for ways to capture and convert rain energy – the kinetic energy of many falling drops, but the breakthrough was only recently made.

Designers from Hong Kong, a region with heavy tropical rainfall, have developed a generator that can receive a voltage of 140 V from a single drop of rain. This is enough to activate, for example, hundreds of small LED lamps.

The generator is based on an electrode of an alloy of indium and tin, coated with Teflon. This material has a quasi-constant surface electric charge, which easily builds up with each new drop. It remains only to bring a second aluminum electrode to it and wait until the spreading rain water closes the circuit. In this case, the accumulated energy is released and the system is again ready for operation.

The ability to accumulate energy on the electrode and obtain significant electric currents compares favorably with the installation of previous systems, where they tried to capture the energy of each drop separately. But even in this form, the generator is not suitable for practical use; engineers have yet to develop mechanisms for a more reliable and, most importantly, controlled process of energy storage and extraction.

As the authors of the development themselves note, most of all they are encouraged by the ability to scale the system. The storage coating can be applied to the roofs of houses and cars, to windows and walls of buildings, even to umbrellas, which will allow collecting the energy of quadrillion drops of rain. And how to apply it, they’ll definitely come up with later.