How exactly does an opposition party force the country to do something like this? Why is it the fault of the Green party, and not of the parties that were in government at the time and made the decision?
That is incredibly biased framing. The main opinion in the broad population at the time was that nuclear power was too dangerous. You're right that the governing parties followed this to stay in power, but how is that then the fault of the opposition party, not of the governing parties?
The green party wasn't able to make this happen or not happen, as they had no governing power. The governing parties were able to make this happen or not happen. They chose to adopt part of the opposition policy to gain political power, but doing this also means they have to accept the responsibility for those decisions.
They might not having governing power, but these opposition parties, as well as NGOs like Greenpeace had a lot of propaganda power that they used for evil.
Even if this were true (and I strongly disagree with both the idea and the framing), it would make the governing parties complicit in the "evil". They could have used their power to fight against the "evil", but instead chose to participate in it to score political points.
Closing down all nuclear plants was first decided on in the year 2000, 24 years ago. It were the Liberals (FDP) and Christian Democrats (CDU/CSU) who rescinded that decision in 2010, only to later reinstitute it in panic after the Fukushima meltdown happened.
Those reactors that got shuttered hadn't had any safety inspections in years, they had no viable fuel left and not even the owning energy companies wanted to operate them any longer than absolutely necessary, so they would have been shut down even without the Green party in the current government.
That the now missing nuclear baseload had to have been replaced with coal, well.. Thank the Christian Democrats for that. They're the ones that favoured building out coal, slowing down the build-out of renewables as much as possible, at every chance they got.
True. However, as I experienced it, there was negligence regarding a base load problem among those favoring renewable energies.
I got into emotionally charged arguments for even asking, "Will Germany produce enough electrical power after shutting down nuclear power stations?" People told me base load was an outdated way of looking at the energy market and a conservative talking point to justify cutbacks in subsidies for renewables. An often repeated argument was that Germany has been a net exporter of electrical power for many years, so reducing capacity should not be a problem.
Personally, I feel that neither side engaged in an honest public debate. I remember very well a leading Green politician, Jürgen Trittin, declaring that the transition towards renewables would cost each German citizen as much as an ice cream cone. Yes, politics must create positive momentum, but being off by orders of magnitude signals fundamental incompetence. The usual counter is, "Had everything gone according to plan, it totally would have worked out." That is childish and not a way to do serious politics.