Potential Energy - Hydropower
Elevation and potential energy in hydropower.
When a body of mass is elevated against the gravitational force - the increase in it's potential energy can be calculated as
Ep = Fg Δh
= m ag Δh (1)
where
Fg = gravitational force (weight) acting on the body (N, lbf)
Ep = potential energy (J, ft lb)
m = mass of body (kg, slugs)
ag = acceleration of gravity on earth (9.81 m/s2, 32.17405 ft/s2)
Δh = 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
Ep = (1000 kg) (9.81 m/s2) (10 m)
= 98100 J
= 98 kJ
= 0.027 kWh
Example - Potential Energy of Elevated Body - in Imperial units
A body with weight (force) 500 lbf is elevated 30 ft. The change in potential energy can be calculated as
Ep = (500 lbf) (30 m)
= 15000 ft lb
A body with mass 15 slugs is elevated 30 ft. The change in potential energy can be calculated as
Ep = (15 slugs) (32.17405 ft/s2) (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.