Calculation of hydroelectric power and energy
Principle
The principle of hydro electricity generation is quite simple. Circuit waterworks provides the necessary pressure of water supplied to the turbine blades, which drives a generator, producing electricity.
Formula to calculate hydropower
How to calculate output power of a hydroelectric turbine? The simplest formula is :
Where
P = Mechnical power in Watt (W)
Q = flow rate in the pipe (m3/s)
ρ = density (kg/m3)
g = Acceleration of gravity (m/s²)
H = waterfall height (m)
η = global efficiency ratio (usually between 0,7 and
0,9)
Calculator
Enter your own values in the white boxes, results are displayed in the green boxes.
Example of stream flow in m3/s, l/minute and l/s, for hydro power calculation
| Water stream | Water flow in m3/s | Water flow in l/minute | Water flow in l/s |
| Tap water (pressure 2-3 bar) | 0.0002 | 10 l/min | 0.2 l/s |
| Fire hose | 0.008 | 500l/min | 8 l/s |
| Very small river | < 2 m3/s | < 120 000 l/min | < 2 000 l/s |
| Small River | > 2 m3/s | > 120 000 l/min | > 2 000 l/s |
| Big River | 100 m3/s | 6 000 000 l/min | 100 000 l/s |
| Very big river | >500 m3/s | >30 000 000 l/min | >500 000 l/s |