One of the arguments against solar and wind is that the renewable energy sources are intermittent and thus unreliable -- the sun doesn't always shine and the wind doesn't always blow. Storage is the key to unlocking the full potential of renewables to power modern, industrial societies on the scale of fossil fuels and nuclear energy. Now, Google's parent Alphabet is joining the race to develop clean energy storage. The Malta project uses cold antifreeze and hot salt to store power.
from Inhabitat - Green Design, Innovation, Architecture, Green Building http://inhabitat.com/google-wants-to-solve-renewable-energy-storage-with-salt-and-antifreeze