What is the theory or concept behind the topic?
Green energy is being used each day. Wind or water current turbines, hydroelectric dams, geothermal heating/cooling, biofuels and solar panels are all being constantly improved to be more efficient and environmentally friendly. Currently, roughly 7% of the world’s energy is generated from these renewable sources. However, there is a green source of energy that has not yet been fully tapped on yet, i.e rain. The potential energy of 25.4 mm (1 inch) of rainfall on the average single story house, if captured at the roof height, provides approximately 120 kJ of energy. This is even more if the rain can be captured in motion.
In addition, the water itself could be stored for a variety of everyday uses. Norway gets 70% of its electricity from hydro-projects, while Denmark gets its electricity from wind and other renewable sources; in France, 90% of electricity is generated via nuclear power-plants.