Germany has around 80GW of capacity in fossil fuel plants so it can generate pretty much all of its electricity from that alone. The reasons it doesn't are:
1) it's cheaper to use excess wind and solar from neighbouring countries which is the vast majority of its imports. Prices in Germany have gone down dramatically since the nuclear shutdown
2) it's better for the environment
So it's basically a win win and far away from disastrous. What is disastrous is when a quarter of your nuclear fleet goes offline unexpectedly and you need to import electricity in the middle of the biggest energy crisis of the last 50 years. And you need to nationalize the electricity company because it made a hole of 20 billion in a single year.
1) it's cheaper to use excess wind and solar from neighbouring countries which is the vast majority of its imports. Prices in Germany have gone down dramatically since the nuclear shutdown
2) it's better for the environment
So it's basically a win win and far away from disastrous. What is disastrous is when a quarter of your nuclear fleet goes offline unexpectedly and you need to import electricity in the middle of the biggest energy crisis of the last 50 years. And you need to nationalize the electricity company because it made a hole of 20 billion in a single year.