For grid scale, novel batteries, such as thermal and gravity, are just about to "cross the chasm" and jump onto the cost learning curve. In 15-20 years time, th

For grid scale, novel batteries, such as thermal and gravity, are just about to "cross the chasm" and jump onto the cost learning curve. In 15-20 years time, they'll be cheap and plentiful. For residential, batteries are being added to appliances. Much cheaper (not panel upgrades) and much larger potential market size (apartments, condos) than "powerwall" style storage. These will follow the standard replacement rate of appliances, accelerated by incentives. Sodium batteries are just starting to hit scale. Of course they'll replace lithium for stationary storage. I don't know enough to predict how big of a role they'll have in grid scale systems. Thermal batteries will be super competitive. And of course, there's many more aspirants. Like flow batteries.