As a result of European climate and energy policy for the integration of renewable energy sources (RES), and to further the decision made by European politicians to speed up the functioning of the internal energy market (IEM), the so-called Third Energy Package was introduced. The Third Energy Package, among others, establishes the harmonised cross-border rules for ENTSO-E system. Common rules are introduced into the European legislation as individual Regulations (i.e. as network codes or guidelines) in individual fields: for the electricity market, power system operation, and requirements for connecting significant grid users to a network. The Network code on requirements for grid connection of generators (NC RfG) falls under a class of network codes which, together with Network Code on Demand Connection (NC DCC) and Network Code on HVDC Connections and DC Connected Power Park Modules (NC HVDC), define the connection of significant grid users to the network, and as a Regulation has entered into force on 17th of May 2016.
In relation to the existing Slovenian legislation, NC RfG imposes additional tasks and processes to transmission system operator (TSO) with respect to the grid connection of power generating modules (PGM). NC RfG enables the integration of RES, and as such the need to upgrade the existing transmission system operation rules, described in the Operation Handbook for Continental Europe, according to the guidelines of the Regulation guideline on electricity transmission system operation and Regulation guideline on emergency and restoration, which both shall enter into force in 2017.
By comparing NC RfG with the existing requirements and procedures that are specified in the Slovenian legislation by SONPO (remark: Slovenia grid code for transmission system), one can define, in general, the new tasks and processes imposed by NC RfG in which TSO is involved, or are implemented by TSO:
1. Determination of the non-exhaustive requirements for PGM (NC RfG, Article 7, Regulatory aspects), which are given in NC RfG, TITLE II: Requirements. The timeframe to submit a proposal on the non-exhaustive requirements: the relevant system operator or TSO shall submit a proposal for requirements of general application, or the methodology used to calculate or establish them, for approval by the competent entity within two years of entry into force (NC RfG, Article 7 (4));
2. Determination of the limits for thresholds of PGM type B, C and D (NC RfG, Article 5 (1) (2) (3) (4) (5), Determination of significance). A proposal by TSO to change the thresholds can be proposed after every three years from the previous proposal (NC RfG, Article 5 (3));
3. The retrospective application process for the requirements of the existing PGM (NC RfG, Article 4(1)(b)(3)(4)(5)(6)(7), Application to existing power generating modules). TSO may assess the application of some or all of the provisions of NC RfG to the existing PGM every three years (NC RfG, Article 4(7)) in line with the criteria and the process defined in Article 4(3)(4)(5) and TITLE III: Operational notification procedure for connection, Chapter 2: Cost benefit analysis (NC RfG, Article 38, Identification of the costs and benefits of application of requirements to existing PGM);
4. The application process for the requirements of the existing PGM (type C, type D) regarding the plant modernisation or the equipment replacement that affect the technical capabilities of the power generating module to such an extent that its connection agreement must be substantially revised (NC RfG, Article 4(1)(a)(i)(ii)(iii), Application to existing power generating modules);
5. The procedures that define the connection of the new PGM to the network (Title III, Operational Notification Procedure For Connection, Chapter 1, Connection Of New Power Generating Modules (NC RfG, Article 29-37));
6. Compliance procedures (Title IV, Compliance (NC RfG, Article 40-57));
7. Derogations procedures (Title V, Derogations (NC RfG, Article 60-65);
8. Establishing the amendments of contracts, and general terms and conditions (Title VII, Final Provisions (NC RfG, Article 71 (1)(2)(3) Amendment of contracts and general terms and conditions).
In addition to the new tasks and processes in NC RfG, we also have the so-called exhaustive requirements (Title II: Requirements, analyzed in Chapter 5 of the master's thesis) that are directly applicable to the Slovenian legislation and other memeber states.
In order to implement the above-mentioned tasks and processes by TSO, it is important to understand how both, the exhaustive and non-exhaustive requirements apply to NC RfG, as well as the concept of NC RfG itself, which the requirements are based upon. For this purpose, the analysis of the NC RfG requirements has been carried out.
Currentlly, the individual members within ENTSO-E are preparing the concept of the NC RfG implementation into their national legislations, and are having discussions between TSO, distribution system operators, national regulatory authority, and member states. Therefore, different expert groups were formed (e.g. to determine the non-exhaustive requirements; to determine the retrospective application of the requirements; to determine the threshold limits for type B, C, and D PGM, etc.) that in addition to stakeholders also include power generating companies, equipment manufacturers, professional institutions, universities, organizations for standardization etc. In Slovenia, unfortunately, we did not pay sufficient attention to it. Thus, an in-depth analysis of NC RfG, demonstrated in this thesis, is necessary. To facilitate the implementation of NC RfG, and the obligations and tasks of TSO, a detailed analysis of requirements is performed, including the power system stability requirements, general system management requirements, and the requirements related to system restoration after collapse. The comparisons of the NC RfG concepts and requirements with the existing Slovenian grid code for transmission system (SONPO 2016) are carried out in this thesis. This thesis highlights the key issues and proposals that the stakeholders will work on during the NC RfG implementation process into the Slovenian legislation.
NC DCC and NC HVDC, whose concepts and terminology is based on NC RfG, will follow in the upcoming months after NC RfG becomes effective. Thus, it is of the utmost importance to both explain the concept of NC RfG in great detail, and to analyse TITLE II Requirements.