Earlier quoted context omitted.
> Or on batteries, or on liquid salt thermal storage upgrades for old fossil plants, or on hydro storage, or on salt cavern pneumatic pressure, or on hydrogen, or on regenerative iron dust cycles, or... And how cost effective are those storage methods?
Compared to gas at pre-war prices, they were getting close but not quite competitive. Compared to current gas prices or nuclear, batteries are dirt cheap and some of the others are almost as cheap as batteries.
[1] https://www.energy.gov/sites/prod/files/2019/07/f65/Storage%... (figures 5.5 and 5.6)