>By comparison the entire world produces ~300 GWh worth of lithium ion battery annually.
And this will increase a hundredfold to make EV production possible.
That means that if 10% of production goes to stationary storage then within 10 years, we'll have 10 full global hours of storage.
If there's serious demand then the supply will scale up to create it.
Also, old EV batteries will provide plenty of extra stationary storage. Not to mention batteries still in EVs, in a pinch.
Realistically we won't throw insane amounts of storage at the problem. We'll make demand more flexible so it does work when electricity is cheap and eases off when it becomes more expensive.
For instance, something like heating: why store the electricity for heating? Wouldn't it make more sense for a house to have some form of heavily-insulated thermal mass that it can massively heat when electricity is dirt cheap, then tap into at midnight without drawing power? Storing heat is cheap, you just need a giant block of concrete with solid insulation. You don't need fancy nanoscale tech like with lithium-ion.
Even something like a kettle: the hot water taps you see at companies that are pre-heated. Have a home-version. Insulate the shit out of that and do 90% of the boiling with peak electricity.
And that's not even touching industrial power usage.
Trying to ape past systems that were based on flat electricity prices just seems like a failure of imagination. Of course it would be expensive, but why the heck would you even want to?