In the recent years, the consideration of the South Caucasus within the EU has considerably evolved. This region, defined as a "neighbor of Europe" in the past, is now seen as a "European neighbor". This proposal intends to highlight how the energy factor, i.e. the transportation of Caspian oil and gas to Europe, has reshaped the interactions and the borders between the EU and the South Caucasus. Until 2003, the relationship between the EU and the South Caucasus was one-sided: Brussels wanted to develop cooperation within this region. However, some European actors were aware that the implementation of the BTC oil pipeline would redefine the borders between Azerbaijan, Georgia and Turkey and challenging those between the South Caucasus and the EU. In the aftermath of the ENP, the EU became increasingly active in the South Caucasus, developing several regional initiatives between these two regions (the Baku Initiative, the Black Sea Synergy, the Eastern Partnership). They led to a redefinition of the borders between the EU and the South Caucasus. The establishment of biregional platforms is supposed to help reinforcing European energy security. The EU is now struggling to implement a Southern gas Corridor and some are strongly advocating for an energy solidarity platform between Eastern Europe and the South Caucasian states. Establishing transregional links, the main issue would not be anymore what is the energy frontier between the South Caucasus and the EU but rather what binds them at the energy level.< Réduire