[cesarb]

> It seems to me that we need at least enough storage to last for a night.

That's only the case if all your generation is from photovoltaic solar. The wind doesn't stop blowing at night, and you need a long drought for hydro to stop producing power.

[adrianN]

Yeah good, then we need enough storage to last half a night and good enough transmission lines to get wind power from wherever it's windy to where the power is needed. That's still a lot more storage than 20 minutes.