If Perpetual Energy isn’t real, then how do Dams generate energy forever?

Question

If Perpetual Energy isn’t real, then how do Dams generate energy forever?

In: Engineering

Answer 1

Dams get their energy from the sun, albeit in a roundabout way.

Water evaporates from the oceans thanks to solar radiation. That water then rains down, forming rivers which flow to the dams and spin the turbines. It is not perpetual motion because it gets energy from an external source (the sun) and that energy source will eventually run out.