When we complain about the rain, other people will often say "Yeah, but it's good for the plants." Well, thanks to a microturbine-based system created by three students from the Technological University of Mexico, it's now also being used to generate electricity for use in low-income homes.
In a nutshell, the Pluvia system – developed by Omar Enrique Leyva Coca, Romel Brown and Gustavo Rivero Velázquez – uses the stream of rainwater runoff from houses' rooftop rain gutters to spin a microturbine in a cylindrical housing. Electricity generated by that turbine is used to charge 12-volt batteries, which can in turn be used to power LED lamps or other small household appliances.
The generator measures about 2 inches wide by 10 inches high (51 x 254 mm), and receives the water through a half-inch (13 mm) pipe. Once the water has flowed through the microturbine, it proceeds to pass through a charcoal filter and into a storage tank, leaving it "equal to or cleaner than the water in the network supply system of Mexico City," according to the students.
The Pluvia system has already been tested in Mexico City's Iztapalapa community. The university now hopes to increase the power of the system, allowing it to generate a greater amount of electricity.
Source: Investigación y Desarrollo (Spanish)