European Union Energy Policy and the Green Energy Transition: A Comparative Economic Analysis of Romania, Poland, Germany, and Spain

Abstract

Energy security, decarbonisation, and transition costs are all central components of the European Union’s sustainability strategy. Even though from a policy perspective the transition to green energy is mostly linear, its economic outcomes differ significantly across member states, generating uneven risks and regulatory challenges. This paper aims to examine how EU policy instruments, particularly the European Green Deal and REPowerEU, generate different economic effects in distinctive national contexts using a comparative framework. The study focuses on four distinct transition models: Romania and Poland as Central and Eastern European economies with structural constraints and Germany and Spain as more advanced adopters of renewable energy. The analysis covers the period 2018–2023 and integrates key indicators such as renewable energy share, gross domestic product growth, and energy prices. The findings indicate that EU policies produce different economic outcomes across countries, depending on nation-specific factors, including energy mix, institutional capacity, and policy stability. Spain emerges as the most balanced case, while Romania records strong results that are partly explained by structural advantages, namely pre-existing hydropower capacity. Germany’s transition appears more cost-intensive, whereas Poland remains burdened by fossil fuel dependence and slower adaptation to transition goals. These differences highlight the varying economic risks associated with the transition and the uneven effectiveness of regulatory frameworks across member states. This study contributes to the literature by linking EU policy instruments with economic outcomes in a comparative perspective, highlighting how national structural differences shape the effectiveness of the green energy transition. The findings suggest the need for differentiated policy approaches within the European Union and provide insights for improving regulatory design and managing transition-related risks. At the same time, the study provides a foundation for future research on energy transition pathways, as it is tailored to national economic structures in order to improve both the efficiency and economic sustainability of the transition.