No, solar and wind are unstable and don’t match demand. Fossil fuels fill that niche right now.
I've been through Nevada and into Utah, you've got loads of desert, enough to make PV stable.
Wind is much more stable in certain places than others, and certain altitudes than others.
What really makes things unstable is when you don't keep your grid in good shape and it sets fire to a forest. Or acting like Texas and thinking grid connections with other states is somehow bad.
(And I'm saying this as someone who actually likes nuclear, thinks the public perception of the danger is over-stated, and who thinks everyone should have build a lot more reactors decades ago).
I'm expecting most batteries (worldwide) to be used for cars, with bi-directional power so they can function that way (for grid storage) when plugged in. That doesn't say much about what any specific country will do, and as Texas demonstrates, US states can have their own independent energy policies.
No they don’t. They can provide a stable curve during the day at scale. But that doesn’t help with night time or the fact that demand does not peak when the sun does.
Even then, the US covers how many hours of longitude?
Because that's how much extra pre-dawn the west can get from the east, and how much post-sunset the east can get from the west — even just diversifying geographically from San Fran to Cisco Utah* gets you nearly two hours.
* why is a ghost town the most notable place in the area, according to Google Maps?