Germany had been moving away from nuclear power for a long time before Fukushima: The plans for shutdowns were made in 2000, with the last reactors closing in 2015-2020 (there were no fixed dates, but rather remaining production capacities assigned, so e.g. stopping a reactor for a few months of maintenance wouldn't have meant a loss for the operator). A anti-nuclear movement had existed for decades before that, growing more and more in popularity the more people lost trust in the plant operators and the agencies supposed to oversee them: operators failing to report incidents, regular failures in temporary storage facilities (e.g. the "Asse", an old salt mine in which nuclear waste is stored and which started to flood), a never-completed search for an actual long-term storage facility, questions about why the government was paying for so much of that work, ...

Late 2010 the then-current government decided to weaken this and added run-time extensions, against popular opinion which wanted to stay with the 2000 plans. Fukushima pushed this back up to public attention, which caused the government to turn 180 degrees, force the worst reactors offline temporarily and re-implement the 2000 plans.