To make solar power viable, we need a solution for overnight energy storage.
Batteries are complicated.
Do you know what isn't? Water go up. 
To make solar power viable, we need a solution for overnight energy storage.
Batteries are complicated.
Do you know what isn't? Water go up.
What makes sand so great? Water has five times the specific heat capacity.
Edit: OH I see, the sand goes through a phase change. That involves a lot of energy, yeah.
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