Most water vapor enters earths atmosphere by the process of

Sublimation;When anything solid turns into a gas without first becoming liquid,  When the surface layer of snow or ice turns into fog or steam without melting, 

Firstly, the water in the dams hold gravitational potential energy as they are above ground level. the gravitational potential energy is then transferred to kinetic energy as it falls, spinning the turbinethe turbine then spins the generator, which is a large magnet surrounded by metal coils. by doing this, the generator generates electricity. in this action, the energy transfer taken place is kinetic to electric energy