One of the EU priorities for the new century is to achieve simultaneously security of energy supply, sustainability and competitiveness. Energy taxation is a key policy instrument that has a significant impact on energy prices, energy usage and great environmental importance. However, coherence should be ensured with climate change objectives, also in view of Europe's international commitments. Despite the importance of that issue, legal certainty is not guaranteed when EU State aid control rules apply to the energy taxation schemes. In contrast, a large number of conceptual as well as practical problems arise. This is particularly relevant because if an “energy tax” is considered to be “environmental” it can be compatible with the internal market. Moreover, new trends on the ECJ case-law may increase the problems due to its “effects-based approach”. Besides, the current legal framework is under revision and the present financial crisis creates new parameters to the already complex issues. As a result of these factors it is clear that, at this historic current time point, the drawbacks need to be examined in a multi-level way. The project aims to contribute to develop the current research on environmentally-driven taxation on energy with the EU State aid control perspective. We propose a new way to address traditional legal research on environmental taxes: through the EU State aids perspective. The research focuses on the intersection between energy taxation, environmental protection goals and EU State aid law. By clarifying the role of tax benefits on the energy sector, we want to provide elements for improving the current scenario. Academic research and dialogue may help to explore what kind of State aid measures will be understood as affecting to “environmental taxes” in the specific context of the EU State aid law. Whether the understanding of the terms is shared from a tax law perspective, or whether different definitions still apply will determine the way