The low carbon transition of the energy sector towards a greater penetration of renewable energy sources (RES) is one of the most impressive examples of political and economic change in the European Union. For nearly two decades, the European Union was rightly considered to be a frontrunner in RES development and deployment around the world. This culminated in March 2007 when the 20-20-20-targets were agreed under the European Council Conclusions. They aimed at creating a carbon neutral society by 2050 and replacing fossil fuels with renewables. This target requires huge transformations of energy systems and transformative shifts in economics and society. Even as renewables can provide numerous environmental, social, and economic benefits, their fast penetration may cause various societal challenges and encounter many barriers. Therefore, this paper aims to analyse the achievements of select EU countries in renewable energy development. For this purpose, an indicators framework is applied to monitor the RES drivers and achievements, RES penetration, and attained benefits of low carbon transformations. The case study focuses on Nordic and Baltic countries that are EU member states.