Solar power and wind turbine power pump water to a high dam during the day with the excess electricity produced above base load and then at night the dam is used to produce hydro power in conjunction with the available wind.
The water drains out of the turbines into a lake in a closed loop to be stored till it can be pumped back up.
Tarong Power Station operates its Splityard Creek hydro station along this concept. Instead of solar or wind generation it pumps water at night when power demand is low.
