Calculate the pumped storage capacity

Question

Two of the largest dams in Australia’s Snowy Hydro scheme are Lake Eucumbene (4500 GL storage capacity) and Blowering Dam (1628 GL storage capacity), which is situated 803m below Lake Eucumbene.

Calculate the pumped storage capacity if the contents of Blowering Dam are pumped uphill into Lake Eucumbene. Express your answer in units of gigawatt-hours (GWh). You may assume that the acceleration due to gravity g ~ 10 m/s2

Answer 1

Hi John!

We can compute energy from pressure drop and volume. The equation reads:

E = (delta P) (V)

where

delta P = rho g h

We plug in variables and convert from liters to cubic meters:

E = (998 kg / m^3) (10 N / kg) (803 m) (1628 x 10^9 L [1 m^3 / 1000 L]) = 1.305 x 10^16 J

But the problem asks for GWh (not Joules) so we must convert:

1.305 x 10^16 J [1 GWh / 3.6 x 10^12 J] = 3,624 GWh