This thesis analyses the impact of the European Integration Project on private law. While the impact of EU law on private law throughout negative integration created European Private Meta-law, and throughout positive integration evolved to European Private law, this thesis claims that EU law has recently moved a step further in regulated markets by creating selfstanding European Private law. Self-standing European Private law is a normative system of rules at supranational level in which its semantically rigid legal norms suggests the intrusion of EU law into the private order of contractual parties with minor divergences within and among national legal systems. This analytical model explains the legal phenomenon of intrusion and substitution, which is different than the phenomenon of divergence, what has so far been the main focus of legal scholars in comparative private law and approaches to Harmonization. To define and identify self-standing European private law, this thesis proposes a systematic understanding of EU law from what H.L.A. Hart conceptualizes as the Internal Point of View. It contextualizes the private law dimension of EU energy law through a discussion of primary and secondary rules and, most importantly, the linguistic framework of analytic philosophy. In so doing, this thesis claims the constitutive element of self-standing European Private law takes shapes when EU law, through governance modes of lawmaking and enforcement at the EU level, creates a set of mandatory rules applied to private relationships, of which the semantic texture of its language leaves minor space for divergent interpretation and implementation by legal official and market actors. To prove the emergence of a self-standing European Private Law, EU energy Law is the blueprint to test the claim. The thesis pursues a socio-legal investigation on how the private law dimension of EU energy law has changed over three decades of market integration and affected two key market transactions in energy markets: transmission service contracts in electricity, and natural gas supply contracts.