Hydropower is another indirect form of solar energy. It is considered the most mature and environment-friendly renewable energy resource. Hydropower is the renewable energy obtained by water falling from high potential to low potential. The hydro energy is harnessed by using the potential energy of the falling water by running a hydro turbine. This turbine is coupled to the rotor of the electrical generator. A set of three-phase voltages is induced in the stator of the electrical generator.
The water cycle depends on the suns energy. When sunlight falls on the surface of water in rivers, lakes, and seas, the upper surface molecules get warmer. When they get enough energy, they leave the surface and escape into the atmosphere, via the evaporation process. These molecules get cooler when they rise up into the atmosphere. When these molecules pass through the cold areas where the air is cool, they condensate and become water droplets. As the droplet holding capacity of the cold air is lower than the warm air, these water droplets cause the rain and maintain the circulation of the water in the atmosphere. If it rains in the mountain ranges, it becomes ice and makes glaciers. If it rains in the fields, somehow or other it finds its way to the sea and the cycle starts again.