Molten salt, in solar power generation, can be used to store thermal energy collected by a solar power tower or solar trough, in order to generate electricity in bad weather or at night. This is successfully used in semi-commercial solar power plants, e.g. in Spain
but is still in early stages of commercialization.
Salt is being tested in energy conservation and preservation of energy that is generated by some renewable sources as an alternative to batteries. Salt is stored in underground stainless steel containers, and is melted with the excess peak power to a high heat. That heat can (by utilising thermodynamics) be saved for hours and then reused in generators (slowly dispersed during the night or windless periods) up to a time period between 6-24 hours. Can also be utilized to produce cooling effect in large buildings.