Of course the CO² impact per kwh is higher in Germany. The country started two world wars and the winning factions understandably weren't overly eager to see Germany building nuclear proliferation capabilities. For the first 10 years after WW2 any kind of nuclear research was forbidden. For the same reason Germany was also forbidden to have an army in the first years after 1945. That's why nuclear never played a big role in Germany and critical parts of nuclear infrastructure (like fuel rod recycling) are still done in other countries (mostly France).