At the latest with the war in Ukraine, energy policy, which is a hot topic in European politics anyway, moved to the center of political debates. It became clear that moving away from fossil fuel-based energy systems is not only related to reducing greenhouse gas emissions and mitigating climate change, but equally to energy security, energy affordability, and foreign policy strategies. However, national energy systems in Europe are very heterogeneous, as structural conditions like geographic circumstances, economic traditions, and critical policy decisions create distinct path-dependencies, that also shape current national and European energy policy discourses and transition pathways. To outline the specific national pathways in a European context, we are examining data on the development of the European energy system and drawing on examples from individual countries. We first assess the long-term evolution of Europe's energy mixes and then continue with a closer look at the developments of the primary energy source for decarbonization, renewable energy. To assess the overall results of the energy transition in Europe, we develop a scoring system that takes into account both transition successes and greenhouse gas reductions. This scoring system is then applied to the EU-27 and the UK to compare the different countries' results and take stock of the development over the last 20 years. The comparative analysis reveals a variety of transition configurations that will shape the future evolution of the European energy system. Mapping these variations is also important in light of current and emerging conflicts over European energy policy and in assessing medium- and long-term challenges on the path to climate neutrality by 2050.