Natural gas transmission is a monopoly activity. RAE, as part of its responsibilities, monitors and controls the exercise of DESFA’s activities and issues the regulatory framework governing the transmission activity. You can see the main regulatory texts here (NOTE 1):

The Natural Gas Transmission System Operation Code, according to which the operation, maintenance and development of the Transmission System is carried out. The Code regulates the relations of the Operator with the Users of the System. The Right to Use the System (potential Transmission System Users) are those registered in the System User Registry. The following are registered by the RAE, upon submission of a relevant application: (a) the Suppliers, (b) the Choosing Customers, for the quantities of Natural Gas they supply and (c) any person who provides sufficient guarantees of financial solvency and technical competence. RAE examines the applications for registration in the Transmission System User Registry in accordance with the provisions of the User Registry Regulation (Gazette B’451/16.04.2010) and decides whether or not to enroll the applicants in the Registry. After being registered in DESFA’s User Register, a person has the right to enter into a Transmission Contract and/or LNG Facility Use Contract with DESFA, in accordance with the Standard Contracts approved by RAE.

The Natural Gas Transmission System Tariffication Regulation (Decision 98/2023) regulates the methodology for setting tariffs for charging each Basic Activity of the Operator. The determination of tariffs for the non-competitive activity of transmission is the main and exclusive competence of the Energy Regulatory Authority as defined in par.1 of article 41 of Directive 2009/73/EC, so that they do not introduce discrimination between Users. The entry-exit system of Regulation (EU) 715/2009 and the provisions of Commission Regulation (EU) 2017/460 for the establishment of a network code regarding the harmonized structure of gas transmission tariffs are applied.