Hydropower

Water - power potential, head and flow rate

Online Hydropower Calculator

The calculator below can be used to calculate available hydroelectricity.

density (kg/m3)

efficiency

volume flow (m3/s)

head (m)

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)

hydropower, volume flow, head and power generation

Example - Hydropower

The theoretically power available from a flow of 1 m3/s water falling 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 Hydropower

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 an 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

Energy water reservoir

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

Copy the document to your Google Drive or download as a spreadsheet to make your own calculations. 

Related Topics

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

Related Documents

Tag Search

  • en: hydropower hydroelectricity head turbine waterfall river
  • es: hidroelĂ©ctrica cabeza hidroelectricidad rĂ­o turbina cascada
  • de: Wasserkraft Wasserkraft Turbine Kopf Fluss Wasserfall

Need some Expert Advice?

JustAnswer can help you! Talk with a verified expert until your satisfied, 100% money- back guarantee.

Search the Engineering ToolBox

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

Engineering ToolBox - SketchUp Extension - Online 3D modeling!

3D Engineering ToolBox Extension to SketchUp - add parametric components to your SketchUp model

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!
About the Engineering ToolBox!

close