I think it will be a mix of both. Local storage at home is great for some grid independance during blackouts and usually you save some money when you have you o

I think it will be a mix of both. Local storage at home is great for some grid independance during blackouts and usually you save some money when you have you own solar roof. But local storage usually will be more expensive per storage capacity vs. larger storage facilities. This means, a large amount of storage will be there, because it is cheaper. Also the power company can control it better than home systems. And of course there the electric cars which could partially contribute to the grid storage.