> the other 12 hours, so if you wanted to feed the entire California demand from expanded solar generation, you'd need to store up 420 gigawatt hours (1.5 PJ).

> the other 12 hours, so if you wanted to feed the entire California demand from expanded solar generation, you'd need to store up 420 gigawatt hours (1.5 PJ). You'd need 12 kWh of batteries per (average) kilowatt, which would bring the price of storage to above US$13000 per kW at the battery prices I found two years ago, which is slightly higher than the price of thermal power generation. And you'll have to pay this cost every 4-8 years, too. And once you talk about load shifting, you're adding in a while bunch of other invisible costs to accommodate the shifting load. E.g. making it so that trains only run at night and on windy days, that increases cost of logistics across the board, which in turn makes a whole bunch of other goods and services more expensive.