You just don't chuck out a field of solar panels and ignore them.
Modern reactor designs - you do basically ignore them once they are initially set up.
1) electric cars acting as buffers. Particularly rarely-used vehicles could earn some side money for being used in a smart grid.
2) battery storage like Tesla constructed in Australia
3) hydro pumped storage
In particular, base load could also be generated by permanent renewable energy (e.g. geothermal or running-water hydro power aka dams) to ease the requirement for energy storage.
Bidirectional V2G systems only exist as demonstration projects now, and we'll need a bunch of time to ramp that up. It requires a lot of EVs, lots of grid updates all over the place, and for people to willingly participate at a meaningful scale. This won't be cheap and the grid we have now can't handle it.
Not likely to be a widely useful storage mechanism except in very specific geography.
A little more than the area of West Virginia [1] if you're only going for solar power using conventional panels.
[1] https://www.axionpower.com/knowledge/power-world-with-solar/