The "rare-earths thingy" is a common, transparent lie told frequently about both solar and wind. No rare-earths are used in any solar panel. Some wind turbine generators have used them, but not the big ones. And, "rare-earths" are not in fact rare. So, a double lie.

Solar panels provide cheap power generation on a schedule. For dispatchability, you rely on storage. There are many different kinds of practical, efficient storage; which are used where will depend on local conditions. Which will be cheapest isn't clear, but probably not batteries. Batteries used won't need lithium, or rare-earths, either

The lie most frequently repeated is that storage needs some sort of "breakthrough". Second is that the small amount built out means more than that there is not enough renewable power yet to charge it from; when there is will be time to build it. In the meantime, we fill in with NG burning. The third is that "pumped hydro", the most common used just now, needs "special geography". Hills are very common.

The lie most frequently repeated about solar is that there is any shortage of places to put it. It is most efficiently floated on water reservoirs, where it cuts evaporation and biofouling, although efficiency is only one consideration. It shares nicely with pasture and even crop land, cutting water demand and heat stress without reducing yield.

There will never be any shortage of wind or solar: need more, build more; materials needed are all abundant. Likewise storage. Costs are still falling as fast as ever, but are already lowest of any energy source ever known.

> And, "rare-earths" are not in fact rare.

It's not a lie but is an unfortunate synonym. They are rare in the sense that they are rarified, spread thin everywhere not concentrated in ores.

They are in ores, but are mixed with other lanthanides that they are expensive to separate from. Two of them, yttrium and scandium, are not lanthanides and are relatively easy to separate out.

A new powerfully magnetic iron-nickel allotrope may eliminate much of the market for several of them.

In regards to your first question, the word you're looking for in google-able energy industry jargon is "dispatchable". And yes, dispatchability of intermittent generation is achieved in a couple of ways in contemporary electricity networks:

  1. Deliberately backing off wind or solar generation from full capacity to provide reserves for demand spikes, transmission/generator outages, etc.  This means other generation that may otherwise not have generated at all over that period, is brought online to cover the shortfall.

  2. Co-locating grid-scale batteries at intermittent generation sites ("hybrid generation facilities" in energy industry jargon) to cover short-term contingency events.

Thank you, not my industry and not my language so “dispatchable” is a valuable keyword for me. ( it would be “pilotable” in French; if you ever have to discuss that abroad with my snotty kind )

Anyway. What I read is : having something else on the side can make solar dispatchable. Realistically, what would be that other things ?

Nuclear don’t like to be turned on/off. Wind has the same issue… are we saying the good ol’ coal burning kettle ?