- They need something to provide electricity when the sun is not shining, while they install enough batteries and more than enough solar to use during the day and charge those batteries.

- They need some backup in case the Sun is dimmed for a few days, while they install enough solar to not need this anymore.

- They need some backup in case they grow too fast and the solar installations don't keep up.

- They need some backup in case there's some natural catastrophe, or some stupid dictator somewhere decides to start a war or something and destroy some vital energy infrastructure.

Their government has explained this a few times, but not on those words. It probably helps that those are government projects, and failing to deliver government projects is a very rude attitude that can end people's careers. But the rationale is sound too.

"and the solar installations don't keep up.".

Whats the average time it takes to build a solar plant versus a coal one? I would assume solar is a lot faster to first production?