Potential Energy - Hydropower
When a body of mass is elevated against the gravitational force - the increase in it's potential energy can be calculated as
E p = F g Δh
= m a g Δ h (1)
where
F g = gravitational force ( weight ) acting on the body (N, lb f )
E p = potential energy (J, ft lb)
m = mass of body (kg, slugs )
a g = acceleration of gravity on earth (9.81 m/s 2 , 32.17405 ft/s 2 )
Δ h = change in elevation (m, ft)
Example - Potential Energy of Elevated Body - in SI units
A body of 1000 kg is elevated 10 m . The change in potential energy can be calculated as
E p = (1000 kg) (9.81 m/s 2 ) (10 m)
= 98100 J
= 98 kJ
= 0.027 kWh
Example - Potential Energy of Elevated Body - in Imperial units
A body with weight (force) 500 lb f is elevated 30 ft . The change in potential energy can be calculated as
E p = ( 500 lb f ) (30 m)
= 15000 ft lb
A body with mass 15 slugs is elevated 30 ft . The change in potential energy can be calculated as
E p = ( 15 slugs ) ( 32.17405 ft/s 2 < ) (30 m)
= 14478 ft lb
Potential Energy in a Tank or a Reservoir - Spreadsheet Calculator
You can estimate potential elevation energy (hydropower) in a tank or a reservoir by dividing the volume in horizontal slices and calculate the elevation energy for each slice - as it is done in the spreadsheet calculator below:
You can copy the spreadsheet to your Google Drive or to your local drive if you want to use it as a template for your own calculations.
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• Mechanics
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