Why are you worried about STORING power?  

As electricity moves to more of a real-time market pricing, the government woven glove over the invisible hand of the market will take care of the NEED for storage.

People can run their delayable loads when power is cheaper, things like charging the electric car, washer, dryer, et la.

If the shipping by electric rail infrastructure is constructed properly (along with tax law changes to make JIT shipping not advantatagous tax wise) when there is excess electrical power, the freight trains move.

The present POV WRT electrical power - flip a switch and its there, will just have to change.   Variable pricing based on resource aviablity will force the change is all.

Wind varies in an order of minutes. What you suggest would require that the price of your power changes every 5 minutes and all you do the whole day is watch the weather forecast and rush to switch your AC on and off.

Can you imagine the losses that a loss of power would cause for a aluminium factory for example? Sorry, but this is a total nonsense.

You don't switch your A/C on and off, it monitors the markets and does it for you.  You don't have any disruption of climate control because it's storing cooling as ice when power is cheap.

Besides, the variations in wind power go down the bigger the area covered by the wind farm is.