types of hydropower systems

Micro hydroelectric systems convert the energy in the running water – usually a small stream - into electricity. The systems are based on three basic elements: 1) the stream/river and, in the most common type of hydropower system, a dam/reservoir; 2) a turbine and 3) a generator…

Other additional elements include : a system of gates related with the dam, a transformer that takes the AC and converts it to higher-voltage current, power lines, a neutral wire, outflow pipelines…

The amount of electricity

The electricity produced by a hydro project depends on the amount of water flowing in the stream and on the velocity of that water.

Image: India Hydropower Association

Types of micro hydropower systems

The most common micro hydro project uses a dam/reservoir to retain water from a stream. That water – once released – turns a turbine, which spins a generator, producing electricity.

In this system, the water is accessed and used responding to the electricity demand. During higher demand periods, the system releases more water and the turbines and the generators work to respond to those higher needs. In the lower demand periods the system works slowly or not at all…

Run of the river hydropower systems

The run of the river hydro system uses a canal or pipe – to which a portion of the water of the stream or river is diverted - and it is the water coming from that canal or pipe that turns the turbine...

Run of the river hydro projects are in many cases the most simple hydropower systems, and do not use a dam (when it uses, it's just very small and unobtrusive dam...).

Dammed hydropower systems

Damned hydro systems are more complex. They use a dam and also a pumping and storage system to store the water in the off-peak periods, in order to maximize the production of electricity in other periods.

When the electricity is most needed, these systems operate like the basic hydropower system, referred first.

During the periods of low electricity needs, the system uses electricity from the grid to turn the turbines backward, pumping water from the stream or river to the storage/reservoir system. The goal of that is obvious: storing as much water as possible to respond to high-demand periods.