If you're in the Atacama Desert, I doubt it's 40%, but not really relevant.

This is ALL renewables, not just Solar - the article states that Solar is ~20% now in the EU.

Wind typically counts for ~15%, and Hydro (which may or may not be counted as renewable) counts as ~15%.

So most places can pretty easily get to ~40% solar, ~15% wind, ~15% hydro = ~70% renewable.

Throw in ~20% Nuclear (basically all of Europe before Germany sh*t the bed), and you're at ~90% - with limited need for storage - a large portion of which could come from infra that already exists for pumped hydro and regular overnight solar storage.

We're quite a ways away from diminishing returns.

We're ~8 years away from a global ~40% of electricity coming from solar EVEN IF it continues to grow at ~30% YoY.