# Hydropower

## Water - power potential, head and flow rate

### Online Hydro-power Calculator

The calculator below can be used to calculate available hydroelectricity power.

density (kg/m3)

efficiency

volume flow (m3/s)

The theoretically power available from falling water can be expressed as

Pth = ρ q g h                      (1)

where

Pth = power theoretically available (W)

ρ = density (kg/m3) (~ 1000 kg/m3 for water)

q = water flow (m3/s)

g = acceleration of gravity (9.81 m/s2)

h = falling height, head (m)

### Example - Hydro-power

The theoretically power available from a flow of 1 m3/s water with a fall of 100 m can be calculated as

P = (1000 kg/m3) (1 m3/s) (9.81 m/s2) (100 m)

= 981 000 W

= 981 kW

### Efficiency

Due to energy loss the practically available power will be less than the theoretically power. Practically available power can be expressed as

Pa = μ ρ q g h                (2)

where

Pa = power available (W)

μ = efficiency (in general in the range 0.75 to 0.95)

### Energy from Hydro-power

The potential theoretical energy in a volume of elevated water can be calculated

W = ρ V g h                      (3)

where

W = energy (J)

V = volume of water (m3)

#### Example - Energy in Elevated Water Volume

A water volume of 10 m3 is elevated 10 m above a turbine. The potential energy in the water volume can be calculated as

W = (1000 kg/m3) (10 m3) (9.81 m/s2) (10 m)

= 981000 J (Ws)

= 981 kJ (kWs)

= 0.27 kWh

### Potential Energy in a Tank or Reservoir

You can estimate the total energy in a tank or a reservoir by integrating the potential energies for horizontal segments as done in

## Related Topics

• Environment - Climate, meteorology, sun, wind and environmental resources

## Tag Search

• en: hydropower hydroelectricity head turbine waterfall river
• de: Wasserkraft Wasserkraft Turbine Kopf Fluss Wasserfall

## Search the Engineering ToolBox

- "Search is the most efficient way to navigate the Engineering ToolBox!"

## Engineering ToolBox - SketchUp Extension - Online 3D modeling!

Add standard and customized parametric components - like flange beams, lumbers, piping, stairs and more - to your SketchUp model with the Engineering ToolBox - SketchUp Extension/Plugin - enabled for use with the amazing, fun and free SketchUp Make and SketchUp Pro . Add the Engineering ToolBox extension to your SketchUp from the Sketchup Extension Warehouse!

Translate the Engineering ToolBox!