With possibly no reduction in electricity emissions through 2022 (as the remaining nuclear is shut down)
Look at the Energy Industry portion of the graph you posted. CO2 emissions moved up a small amount in the two years post the Fukushima disaster as Germany sped up reactor closing. And then they fell following two years. Electricity related CO2 was apparently up about 1% in 2016 due to increased demand.
It will take about five more years to close the remaining nuclear plants and we shouldn't be surprised if that keeps electricity related CO2 from significant falls. Renewable installations will be used to offset reactor losses.
But post 2022 Germany should have no more reactors to close and further renewable installations can be used to eliminate fossil fuel use. That's the story behind somewhat missing the 2020 target but still hitting the 2050 target.
Remember, Fukushima was a major disrupting even for Germany. As a country that had lived through a nuclear disaster in their neighborhood they decided that they wanted to reduce the risk of experiencing another.
Look closely at the bars in your graph. Electricity generation CO2 emissions have dropped slightly from 2009 to 2015. You cherry-picked the lowest pre-Fukushima year out of the record. Use change over a decade and you see a 13% decrease. Not an extraordinary rate, but we're only short years into very affordable wind and solar.
Then look at the other sources of CO2. Look at the non-electricity sectors which have increased.