You don't need battery farms to make renewables viable in the US. What you need is to replace the AC grid interconnect system in the US with a HVDC super grid system.
The key difference here is that HVDC is exceedingly efficient in energy transfer and has effectively negligible losses compared to AC over distance.
The US is big enough that any impact from weather should basically average out over that distance.
There are huge downsides though because moving power generation further and further from where it’s used opens you up to more disruption from terrorist attacks on the grid (and cyber attacks) unless you also do less centralized production which is going to be more expensive.
That's the thing. HVDC works better in a decentralised manner. You don't have clocking to deal with so instead it's mainly a matter of just hooking power production and power draw up to what is basically a big cross-country busbar.
And you can connect as many bridging connections as you want without having to worry about phase or desync. Instead more connections generally just means power goes from production to consumption along more efficient paths.
That doesn't help after sunset on the west coast when residential demand peaks and there is little renewable power being generated anywhere in North America. In theory batteries or other storage could close that gap but realistically it's going to take decades to scale that up.
That's 16 hours of sunlight but more importantly that allows the US to distribute energy production from hydro, wind, and geothermal production across the country.
During the daylight hours solar is great of course but my point about power averaging out had more to do with the other forms of renewable energy.
The key difference here is that HVDC is exceedingly efficient in energy transfer and has effectively negligible losses compared to AC over distance.
The US is big enough that any impact from weather should basically average out over that distance.