What is the source of energy that powers a hydroelectric power plant?

Question

A. The thermal energy of the water behind dams.

B. The energy of the chemical bonds of water molecules.

C. The sunlight that evaporated water that eventually falls as rain and fills the reservoir.

D. The kinetic energy of wind that carried evaporated water, which fell as rain and filled reservoirs.

Answer 1

Hi, Astara,

Given your four choices, the best/most correct one would be (c) the sunlight that evaporated water that eventually falls as rain and fills the reservoir. It is the potential energy stored in the reservoir water which is "released" as it is converted to kinetic energy (the movement of water which spins the hydroelectric generator turbine, etc.), but the absolute source of that original potential energy comes from the Sun's action to evaporate lake or ocean water which is returned to Earth as rain ... and it is this rainwater which ultimately fills the reservoir behind the hydroelectric power plant.

'Hope that helps,

Chris