Russia's invasion of Ukraine had a massive impact on the energy supply of EU member states. The question of how and when Europe could free itself from its heavy dependence on Russian fossil fuels was of utmost importance for the sustainability of the EU sanctions and the economic and social resilience of the EU countries. A series of FES papers that have been published throughout the second half of 2023 describe how EU countries have responded to the supply crisis following the Russian invasion of Ukraine and how these reactions affect long-term energy policies in various countries. In sum, the picture that emerges is one of joint and consistent action by the states of the EU, which were able to detach themselves from the supply of fossil fuels from Russia to a surprisingly high degree in a surprisingly short period of time.
See the Survey here https://library.fes.de/pdf-files/bueros/budapest/20680.pdf