Fission is too expensive. The good real reasons from a cost perspective for reactors are weapons, medical and industrial applications as well as research.
Why would you want to use battery storage instead of pressure or gravity, for example? You can do gravity by moving stuff around underground, not just classical pumped storage. Digging big and deep holes is something people know how to do quite well, same goes for moving weights/mass up and down.
Could also do some chemical storage as another avenue.
For heat you can have certain thermal storage, too.
Reducing emissions related to transportation leads to electrical vehicles, and therefore to a vast amount of batteries, most not used at any given moment and therefore ready to store overproduction or release needed electricity.
This very average frequency/amplitude/speed of discharge, for any given battery, depends upon many parameters (during most of such 'call to batteries': slope of the call and quantity of electricity needed, duration, proportion of vehicles connected to the grid...).
This is part of the solution, as we have ways to reduce effects of intermittency on production (mainly a mix spread over the continent), other ways to store electricity (hydro, green hydrogen-burning turbo-alternators...), and curtailment...
Why would you want to use battery storage instead of pressure or gravity, for example? You can do gravity by moving stuff around underground, not just classical pumped storage. Digging big and deep holes is something people know how to do quite well, same goes for moving weights/mass up and down.
Could also do some chemical storage as another avenue.
For heat you can have certain thermal storage, too.