From your article:

concentrated solar thermal with 15 hours of thermal storage 15-20%; and the small remainder supplied by existing hydro and gas turbines burning renewable gases or liquids. (Contrary to some claims, concentrated solar with thermal storage does not behave as base-load in winter; however, that doesn’t matter.)

The real challenge is to supply peaks in demand on calm winter evenings following overcast days. That’s when the peak-load power stations, that is, hydro and gas turbines, make vital contributions by filling gaps in wind and solar generation.

So basically the concentrated solar w/ thermal storage acts as a battery. I’m interested to know what the costs look like (is that the salt reactor thing I’ve heard about). And if you have lots of hydro available, then yeah, you can probably get away with it, and may even be able to pump water so the hydro station can act as a battery. However, hydro isn’t practical in many areas, and moving electricity long distances may be too lossy.

I’m interested in the development of nuclear microreactors, which can be transported where they’re needed. I think they could potentially replace hydro in areas where it’s not available. So as areas transition to more renewables, these could operate as a backup in case simulations don’t match reality.

I’d love to go 100% renewable, I just don’t think that’s feasible at the moment. But I could absolutely be wrong, I may need to read up on the latest energy storage options.