In the wake of the European Union’s (EU) enlargements in 2004 and 2007,
which saw the accession of 12 new member states, lengthy debates and
discussion took place on the burden of onboarding the new member states,
the difficulty of ensuring their compliance with EU rules and regulations and
the dependence of many of these states on a single supplier for their energy
needs. This paper aims to assess the EU’s efforts to form a comprehensive
energy security policy in recent decades, paying particular attention to the
development of the theory of energy security and the main developments of
the EU’s energy security policy in recent years. The Energy Union, a flagship
initiative launched by the European Commission in 2015, will be assessed
through an examination of its governance structure and achievements in
specific policy domains
