Panels are cheap enough that you can overprovision for winter sun.

There are a gazillion battery techs being developed right now (regular lithium ion - with variations like NMC, LFP, ...), solid state lithion ion, sodium ion.

You can over provision solar as someone said.

There's geothermal, tidal, etc.

Long distance high voltage electricity transmission at scale.

Electricity is a marvel and we're just starting to scratch the surface of what we can do with it. Betting against it is like betting against electronics, a risky proposition.