It's the result of cheap fossil fuels, provided by Russia.

There is no shortage of electricity in Germany, so there was no economic interest to build more nuclear power plants? Germny even exports electricity to France, which has a lot of nuclear power plants (many of which currently don't work).

We don't even know where to safely put the waste for the next million years. Germany doesn't have the huge inhabited areas like the US - and even they have not solve that problem yet.