Here is another idea for utility scale electrical storage. Problem is it, you need to have the right geology to utilize it.
Compressed air energy storage - Wikipedia, the free encyclopedia
In my mind, we need almost ALL renewable energy generation & storage schemes to replace our current dependency on fossil fuels; coupled with serious investment in energy efficiency at all levels.
Most people just don't get the enormous & unique energy storage density of gasoline, its ease of transport & how really it is impossible to replace. You can substitute for some things, but the substitutes just aren't as good. Problem is the cheap oil has already been burned....