Info on Hydro

Micro Hydro systems generate electrical power from the force of gravity acting on water.

For this to work you must have a head of water, a difference in height between the points where the water enters and leaves the system.



To be viable a potential hydro site must have sufficient HEAD and FLOW.

The Flow is defined by the average annual rainfall in mm x the catchment area in square km.

Usually systems are design to run at maximum capacity on 1.3 x mean or average flow of a particular stream at a point immediately above the intake.


The basic equation which defines how much power a particular system can generate is:-




The higher the head, the lower the flow required to generate a specific output of power.

The higher the flow, the lower the head required to generate the same output of power.


Co-Hydro specialise in high head systems. Each of our systems is designed for a specific head and maximum flow which optimises the potential of a particular site.

We generally design and build systems for sites with between 80 metres and 180 metres of head or height difference between the intake point and turbine.

Maximum flow capacities are between 45litres per second and 140 litres per second.



A site which had 100 metres of head and a maximum available flow of 102 litres per second with a system efficiency of 0.75 would have a maximum generating capacity of 75kW.

A site which had 180 meters of head would require a flow of 57 litres per second in order to generate 75kW.