His data might have been wrong but 20GW of nuclear extra nuclear would still be incredibly useful.

Let alone simply building more of it and solving the problem.

Because its of course easy to say that 50% is coming from X but this is bought with under capacity in the rest. If you have a long time period where you have low wind and solar utilization you need backup that you can ramp up.

Most of that 20GW is long gone and decommissioned. Only three plants (8GW) remained at the beginning of the year. It's not nothing. But also not that much. Only two plants remain now.

Nuclear is very bad at ramping up. It's very expensive to shut down and restart nuclear plants. One of the headaches with the remaining plants is that they would have been due (over due actually) for a lengthy shutdown for maintenance and inspection reasons. The two remaining plants will be kept online until April 2023 now; a few months past their original closing date. By then, most of the French plants that have been offline for maintenance should be back online. As others have noted, France has been leaning on German energy exports a bit more than usual for this reason.

Yes that's the point right. It's gone and decommissioned for really bad reasons. A political deal that satisfied those who were more anti-nuclear than anti-pollution. In an alliance with those who were more pro-fossil-gas than pro-climate. And now Germany pollutes many times more than it otherwise would. We should absolutely take a lesson from this.

As mentioned taken from a snapshot at the time of Electricity Maps, check it out: https://app.electricitymaps.com/map

So when you said "currently" you actually meant "right at this moment". Because currently (as is "this year") about 50% of Germany's electricity generation comes from renewables.

Right. But if you want to look at 12 months (fair enough) then 50% being dirty electricity generation is nothing to be proud of is it? It's still one of the dirtiest grids in the planet with an average >500gCO2/kWh. And it's average coal production over that time appears to be 21.2GW. So if over a 12 month period then if Germany had retained it's nuclear it would replace MORE than half of it's fossil fuel produced electricity. Even better.