Renewable is cheap, but not that cheap.

Also, solar production and heating needs are anticyclical.

Also, the European grid is big (the biggest!), but not so big it can deal with seasons and weather patterns. Yet. Or ever.

The idea was that gas would fill in the gaps, until energy storage at scale becomes a thing (no, it is still nowhere near scale, only gas reserves can fill that role right now). Germany is investing heavily in hydrogen to fill this gap, but barring fundamental breakthroughs, I think it's a pipe dream. A 90% (roughly) total efficiency loss means 1000% oveprovisioning of generation capacity. That's expensive, even when cheap.