Hydropower is the renewable energy contained in flowing water. Electricity generated using hydropower is known as hydroelectricity and is generally considered to be reliable.
All over there are three main methods for generating hydroelectricity:
Storage – where a dam collects water in a reservoir, then releases it to drive turbines, producing electricity
Pumped storage – where water is pumped to a higher reservoir, usually during times of low-priced electricity, then released to a lower reservoir, again driving a turbine, usually when the electricity price is higher
Run of river – where the natural flow of a river or stream is used to drive a turbine.
The power plant of a hydroelectric power station is affected by the geography of the site it is built on.