The decision to phase out nuclear is years older than the Fukushima meltdowns. The exit from nuclear had then be reversed by the Merkel administration, a decision which was untenable after Fukushima, so the previous exit from nuclear was reinstated.
Nuclear has only ever produced 25% of the electricity in Germany. It currently produces close to 10%. In the same time frame, renewables have added much more capacity and production than the nuclear reduction took away, and Germany has (net) exported more electricity, not imported more. Germany is part of the European grid and exports and imports even at the same time, and the prices of Germany's electricity imports and exports are balanced.
Ontogeny recapitulates phylogeny.