Question

How can rivers be used as an energy source?

Answer 1

A few methods by which rivers can be used as an energy source:
- hydro-electric power generation
- direct mechanical equipment
- heat source

Explanation:

Hydro-electric
The flow of water can be used to turn turbines and rotate magnets past wire coils generating electrical current in the wire.

Direct mechanical
This is probably one of the oldest forms. Flowing water can be used to turn mill waterwheels to grind flour, cut wood, operate looms, etc.

Heat source
A water flows from a higher to a lower level, energy (in the form of heat) is released. This is particularly noticeable at the bottom of a waterfall where the water temperature will be measurably warmer than at the top.