On the left
Salar de Uyuni, Chile.
This salt desert contains around 5 billion m3 of salt.

Up on the right
Cardona salt mine with salt
mountain, Spain.
It's estimated there is still 250
billion m3 of salt!

Below on the right
Great salt lake, Utah
It containes around 2 billion m3 of salt

The great problem of wind/solar energy is its discontinuity.   
It's not possible to produce great quantity  of wind/solar energy without making it constant during all the year...
NaCl is a great answer to this problem.
1 million m3 of salt is largely available on the earth...and stores 100 million kwh of electric energy, this means that is possible to store  great quantity of solar energy during  summer  releasing it during winter.

Solution of some problems.
Isolation: NaCl isolation can be easily solved with vacuum.
Heat transportation: The heat of vaporization is able to transport great quantity of heat in a few seconds everywhere...
High working temperature:  800 °C  is the same temperature of my old...chimney!!!