Quote Originally Posted by Vaygor1 View Post
The energy used to pump it up is 10%-30% more than the energy gathered when it comes back down, so this is a concept I struggle with as it just such a waste with the only benefit coming from commercial variations due to supply and demand. ie Pump it up when the spot prices (and demand) are low, let it go when the spot price is high.
This really only works where you cant turn off the power generation to match supply. Geothermal is continuous and wind blows when it blows but other thermal and hydro can be shut down, eliminating the need to store that power.