We mostly do not need too much storage today. For that we first need an overproduction of renewables at certain points to actually store and that is unforuntatly not the case today.
As for scale the key technoliges seem to be batteries for shorter storage and hydrogen for longer dunkelflaute. The first is pushed mainly by EV developement, which is going to push down the price for battery packs and built enough factories to have the scale necessary. Hydrogen as a product is needed for chemical and steel production anyway. So we need to built the infrastructure for that including some storage. But development cost will mainly be meet by that.
We mostly do not need too much storage today. For that we first need an overproduction of renewables at certain points to actually store and that is unforuntatly not the case today.
As for scale the key technoliges seem to be batteries for shorter storage and hydrogen for longer dunkelflaute. The first is pushed mainly by EV developement, which is going to push down the price for battery packs and built enough factories to have the scale necessary. Hydrogen as a product is needed for chemical and steel production anyway. So we need to built the infrastructure for that including some storage. But development cost will mainly be meet by that.