Information;Judgment — ECLI:EU:T:2024:652
Date: 2024-09-25
Language of the case: English
Court formation: Third Chamber, Extended Composition
Subject matter: Energy
Procedure: Action for annulment - successful
Origin: Poland

JUDGMENT OF THE GENERAL COURT (Third Chamber, Extended Composition) 25 September 2024 (*) ( Energy – Internal market for electricity – Capacity calculation region – Core region – Adoption by ACER of the methodology for cost sharing of redispatching and countertrading – Determination of the threshold for legitimate loop flows – Article 16(13) of Regulation (EU) 2019/943 ) In Case T‑484/21, Polskie sieci elektroenergetyczne S.A., established in Konstancin-Jeziorna (Poland), represented by S. Goldberg, Solicitor, and by A. Galos and E. White, lawyers, applicant, supported by Republic of Poland, represented by B. Majczyna and M. Rzotkiewicz, acting as Agents, intervener, v European Union Agency for the Cooperation of Energy Regulators (ACER), represented by P. Martinet, Z. Vujasinovic and E. Tremmel, acting as Agents, and by P. Goffinet, L. Bersou and M. Shehu, lawyers, defendant, THE GENERAL COURT (Third Chamber, Extended Composition), composed of F. Schalin, President, P. Škvařilová-Pelzl, I. Nõmm, G. Steinfatt and D. Kukovec (Rapporteur), Judges, Registrar: I. Kurme, Administrator, having regard to the written part of the procedure, further to the hearings on 12 and 13 June 2023, gives the following Judgment 1 By its action under Article 263 TFEU, the applicant, Polskie sieci elektroenergetyczne S.A., seeks the annulment of the decision of the Board of Appeal of the European Union Agency for the Cooperation of Energy Regulators (ACER) of 28 May 2021 confirming ACER Decision No 30/2020 of 30 November 2020 on the proposal of the electricity transmission system operators (‘TSOs’) of the ‘Core’ capacity calculation region, comprising Belgium, the Czech Republic, Germany, France, Croatia, Luxembourg, Hungary, the Netherlands, Austria, Poland, Romania, Slovenia and Slovakia (‘the Core region’), for the methodology for cost sharing of redispatching and countertrading, and dismissing its appeal in Case A-001-2021 (consolidated) (‘the contested decision’). Background to the dispute 2 The applicant is the TSO in Poland responsible for the operation, maintenance and development of the Polish power grid. 3 In accordance with Article 74(1) of Commission Regulation (EU) 2015/1222 of 24 July 2015 establishing a guideline on capacity allocation and congestion management (OJ 2015 L 197, p. 24), all TSOs in each capacity calculation region are to develop a proposal, no later than 16 months after the decision on the capacity calculation regions is taken, for a common methodology for redispatching and countertrading cost sharing (‘the cost sharing methodology’). 4 On 17 November 2016, ACER adopted, in accordance with Article 15 of Regulation 2015/1222, Decision No 06/2016 regarding the determination of capacity calculation regions. Article 1 of and Annex I to that decision list the territories of the Member States included in the Core region. 5 The proposal for a cost sharing methodology of the TSOs of the Core region should have been submitted within 16 months of that decision, that is to say, by 17 May 2018 at the latest. 6 However, the TSOs of the Core region did not submit a proposal for a cost sharing methodology within the time limit referred to in paragraph 5 above. In accordance with Article 9(4) of Regulation 2015/1222, those TSOs informed the national regulatory authorities (‘NRAs’) and ACER that they needed more time to develop such a proposal. ACER informed the European Commission, which consulted with the TSOs, the NRAs and ACER to assist the TSOs in developing that proposal and submitting it for approval as early as possible. 7 On 27 March 2019, in accordance with Article 9(7)(h) of Regulation 2015/1222, the TSOs of the Core region submitted to all the NRAs of that region a proposal for a cost sharing methodology, accompanied by an explanatory document. Those NRAs had a period of six months within which to take a decision on that proposal, in accordance with Article 9(10) of that regulation. 8 On 26 September 2019, at the request of those NRAs, ACER decided to extend the period for them to approve that proposal by six months, that is to say, until 27 March 2020. 9 On 27 March 2020, the Chair of the Core Energy Regulators’ Regional Forum, on behalf of all NRAs of that region, informed ACER that they were not able to reach a decision on the proposal submitted by the same day, the proposal being considered largely incomplete, to such an extent that the NRAs were not in a position to approve it or to request an amendment to it. 10 On the same day, since the NRAs of the Core region had not been able to reach an agreement on the proposal for a cost sharing methodology submitted by the TSOs, ACER declared itself competent to adopt a decision on that proposal, in accordance with Article 5(3) and Article 6(10) of Regulation (EU) 2019/942 of the European Parliament and of the Council of 5 June 2019 establishing a European Union Agency for the Cooperation of Energy Regulators (OJ 2019 L 158, p. 22), and Article 9(11) of Regulation 2015/1222. Under the latter provision, ACER was required to adopt such a decision within six months, in accordance with Article 6(12)(a) of Regulation 2019/942. 11 Following a long period of cooperation, consultations and discussions between ACER, all the NRAs of the Core region and all TSOs of that region on the proposal for a cost sharing methodology submitted by those TSOs and on the amendments made to that proposal during several meetings and rounds of voting, the Board of Regulators of ACER, which is composed of representatives of the NRAs, issued a favourable opinion on that proposal on 18 November 2020, pursuant to Article 22(5)(a) of Regulation 2019/942. 12 On 30 November 2020, ACER adopted, by Decision No 30/2020, the cost sharing methodology (‘Common methodology for redispatching and countertrading cost sharing for the Core CCR in accordance with Article 74 of Commission Regulation (EU) 2015/1222 of 24 July 2015’), as set out in Annex I to that decision (‘the contested cost sharing methodology’). 13 On 29 January 2021, the applicant submitted an appeal to the ACER Board of Appeal against Decision No 30/2020, in accordance with Article 28 of Regulation 2019/942. Other TSOs and NRAs of the Core region also submitted appeals against that decision. On 18 February 2021, the Board of Appeal consolidated all of those appeals. 14 On 28 May 2021, the Board of Appeal adopted the contested decision, by which it upheld Decision No 30/2020 and dismissed in their entirety the appeals brought against it. Forms of order sought 15 The applicant claims that the Court should: – annul the contested decision; – order ACER to pay the costs. 16 ACER contends that the Court should: – dismiss the action; – order the applicant to pay the costs. 17 The Republic of Poland, intervening in support of the form of order sought by the applicant, submits that the Court should annul the contested decision. Law 18 The applicant puts forward five pleas in law in support of its action. 19 The first plea alleges infringement of Article 16(13) of Regulation (EU) 2019/943 of the European Parliament and of the Council of 5 June 2019 on the internal market for electricity (OJ 2019 L 158, p. 54), and of Article 9(11) of Regulation 2015/1222, in so far as the Board of Appeal of ACER accepted, in the contested decision, that ACER could exceed its competence, allowing it to penalise cross-zonal transactions and to set a threshold for loop flows (‘the threshold’) itself. The second plea alleges infringement of Article 296 TFEU, in so far as the contested decision is vitiated by a failure to state reasons as regards the decomposition of flows in the contested cost sharing methodology. The third plea alleges an error of law, in so far as the Board of Appeal found that the decomposition of flows did not contradict the definitions in Article 2 of the contested cost sharing methodology. The fourth plea alleges an error of law, in so far as the Board of Appeal found that the decomposition of flows in the contested cost sharing methodology, leading to an overestimation of loop flows of importing bidding zones, did not infringe Article 74(6)(c) and (i) of Regulation 2015/1222. The fifth plea alleges an error of law, in so far as the Board of Appeal found that the value of the 10% loop flow threshold set by ACER was not too high. 20 ACER contends that all the pleas raised by the applicant should be rejected as unfounded. 21 The Court considers it appropriate to begin by examining the first plea together with the fifth plea, in so far as they relate to the issue of the loop flow threshold. The first and fifth pleas, relating to the threshold 22 By its first plea, the applicant, supported by the Republic of Poland, submits that the Board of Appeal infringed Article 16(13) of Regulation 2019/943 and Article 9(11) of Regulation 2015/1222. 23 In the first place, the applicant claims that ACER was not competent to amend the TSOs’ proposal since its role was limited to the approval of the TSOs’ proposals. According to the applicant, the absence of a provision excluding the possibility of amending the TSOs’ proposal does not allow the extension of ACER’s competence. 24 In the second place, the applicant submits that the Board of Appeal infringed Article 291 TFEU and the principle of conferral of powers referred to in Article 5 TEU, in so far as it insisted, inter alia, that ACER’s powers were limited only by the principles of proportionality and subsidiarity within the meaning of Article 4 TFEU. 25 In the third place, the applicant complains that the Board of Appeal infringed Article 16(13) of Regulation 2019/943, in so far as it accepted that ACER could penalise flows arising from cross-zonal transactions, that is to say, allocated flows, whereas that provision concerns only flows resulting from internal transactions, that is to say, loop flows and internal flows. In particular, under the contested cost sharing methodology, a cross-zonal transaction creates an artificial internal transaction in the importing zone, which in turn results in an additional internal flow and loop flow in that zone, which increases the share of costs borne by that importing zone. 26 In the fourth place, according to the applicant, in adopting a 10% loop flow threshold in the place of the TSOs, ACER unjustifiably departed from the TSOs’ proposals, since the highest threshold proposed by the majority of TSOs was 5%. Assuming that ACER was allowed to decide on a threshold by ignoring the position presented by the majority of TSOs, any such threshold should have been decided on the basis of a detailed impact assessment, that is to say, on the basis of the analysis provided for in Article 16(13) of Regulation 2019/943, which the applicant clarified at the hearing. The applicant adds that the mere fact that the TSOs were unable jointly to analyse and define an appropriate threshold, as required by the second subparagraph of Article 16(13) of Regulation 2019/943, does not mean that ACER could assume for itself the power to adopt such a threshold in their place, even if it were defined on a temporary basis. 27 By its fifth plea, the applicant submits that the Board of Appeal of ACER infringed the ‘polluter pays’ principle referred to in Article 16(13) of Regulation 2019/943 by finding, in paragraphs 959 to 993 of the contested decision, that the value of the 10% loop flow threshold set by ACER was not too high. 28 In that regard, the applicant stated at the hearing that, in its view, the 10% threshold set by ACER in Article 7 of the contested cost sharing methodology had been defined on the basis of an incorrect calculation method and the applicant confirmed, in response to a question from the Court, that it contested the entire mechanism used to determine that threshold. More specifically, the applicant expressly confirmed, at the hearing, that it considered that the threshold should have been defined on a case-by-case basis, for each bidding zone border, in accordance with the procedure laid down in Article 16(13) of Regulation 2019/943. 29 ACER disputes the applicant’s arguments. 30 It is common ground that, even without structural congestion, loop flows are inevitable in a highly meshed interconnected electricity network operating according to a zonal model. 31 For that reason, the purpose of determining a loop flow threshold is to exclude such flows from the sharing of costs incurred as a result of redispatching and countertrading. 32 As regards the determination of the threshold, Article 16(13) of Regulation 2019/943 provides as follows: ‘when allocating costs of remedial actions between [TSOs], [NRAs] shall … allocate the costs … except for costs induced by flows resulting from transactions internal to bidding zones that are below the level that could be expected without structural congestion in a bidding zone. That level shall be jointly analysed and defined by all [TSOs] in a [trading] capacity calculation region for each individual bidding zone border, and shall be subject to the approval of all [NRAs] in the capacity calculation region.’ 33 First, it is apparent from Article 16(13) of Regulation 2019/943 that the threshold presupposes that the level of loop flows that could be expected without structural congestion is simulated. 34 ‘Congestion’ is defined in point 4 of Article 2 of Regulation 2019/943 as ‘a situation in which all requests from market participants to trade between network areas cannot be accommodated because they would significantly affect the physical flows on network elements which cannot accommodate those flows’. 35 ‘Structural congestion’ is defined in point 6 of Article 2 of Regulation 2019/943 as ‘congestion in the transmission system that is capable of being unambiguously defined, is predictable, is geographically stable over time, and frequently reoccurs under normal electricity system conditions’. 36 Second, it is apparent from the second subparagraph of Article 16(13) of Regulation 2019/943 that the determination of the threshold must be preceded by an analysis and that that analysis must be carried out by the TSOs. 37 Third, it is apparent from that provision that the threshold must be analysed and determined ‘for each individual bidding zone border’. 38 In the present case, it is common ground that the TSOs did not carry out the required analysis. 39 It is also common ground that ACER did not carry out that analysis either. 40 In that regard, it is apparent from paragraph 112 of Decision No 30/2020 that, in the absence of a threshold analysed and defined by the TSOs and approved by the NRAs in accordance with Article 16(13) of Regulation 2019/943, ACER examined whether it was in a position to perform that analysis itself and concluded that that was not the case, due to constraints on resources, the time available and the necessary expertise. 41 In addition, it is apparent from recital 8 of the contested cost sharing methodology and from paragraphs 110 to 114 of Decision No 30/2020 that ACER, in such a situation, considered itself authorised to set a temporary threshold itself. 42 Moreover, it is apparent from paragraphs 115 to 122 of Decision No 30/2020 that ACER set the temporary threshold for the whole of the Core region uniformly at 10% of the maximum capacity of each network element concerned and then divided that threshold equally between all of the bidding zones that create loop flows on the network element concerned. 43 In the contested decision, the Board of Appeal rejected as unfounded the criticism relating to ACER’s determination of a temporary threshold for the reasons set out in paragraphs 909 to 1077 (pages 137 to 164), 1210 to 1221 (pages 187 to 189) and 1192 to 1226 (pages 212 to 218) of the contested decision. 44 In that regard, it is apparent in particular from paragraphs 924 to 946 (pages 140 to 144), 1217 to 1221 (pages 187 to 189) and 1199 to 1226 (pages 213 to 218) of the contested decision that ACER considered that it had to set the threshold itself, given that the setting of such a threshold was, in its view, essential in order to be able to adopt the cost sharing methodology. 45 Furthermore, it is apparent from those same paragraphs of the contested decision that ACER’s determination of the threshold was based on a ‘rigorous analysis’. 46 It is also apparent from those parts of the contested decision that the Board of Appeal considered that ACER was authorised, or even obliged, to set a temporary threshold itself without having at its disposal the analysis prescribed in Article 16(13) of Regulation 2019/943, in order to avoid a deadlock situation. 47 In that regard, the temporary nature of the threshold thus set by ACER is emphasised in the contested decision. It is apparent from paragraph 943 (page 143) of that decision that the TSOs may still carry out the analysis required at any time and that NRAs may at any time replace the temporary threshold laid down in the contested cost sharing methodology with a definitive threshold. 48 In the light of the foregoing, it must be examined whether the Board of Appeal was entitled, without erring in law, to find, in the contested decision, that ACER’s determination of the threshold in the contested cost sharing methodology complied with the requirements stemming from Article 16(13) of Regulation 2019/943. If that is not the case, it will be necessary to examine whether, as the Board of Appeal noted, ACER, in the particular circumstances of the present case, could nevertheless rely on an implicit competence authorising it to determine a threshold in a different way than that established by that provision. Compliance with the requirements of Article 16(13) of Regulation 2019/943 49 In accordance with Article 16(13) of Regulation 2019/943, the threshold is to be analysed and defined ‘for each individual bidding zone border’ and must correspond to the ‘level that could be expected without structural congestion’. 50 In the first place, it must be examined whether the method for determining the threshold followed by ACER in the contested cost sharing methodology, confirmed by the contested decision, complies with the requirement for that threshold to be analysed and defined ‘for each individual bidding zone border’. 51 In that regard, it is apparent from Article 7(3) and (4) of the contested cost sharing methodology that the threshold is determined in two stages. 52 In the first stage, a common threshold for the whole of the Core region is applied to each cross-border relevant network element. That common threshold is set at 10% of the maximum capacity of the network element concerned. 53 In the second stage, the common threshold is divided equally, for each network element concerned, by the number of bidding zones within the Core region from which the loop flows that pass through that network element originate. If a bidding zone does not fully use the share of the threshold allocated to it, the unused part is then divided equally between the remaining bidding zones. 54 It follows that the threshold of each cross-border relevant network element corresponds to 10% of its maximum capacity, divided equally by the number of bidding zones within the Core region from which the loop flows that pass through that network element originate. 55 It is true, as ACER submits, that such an allocation results in an individual threshold for each bidding zone and, therefore, that that determination of the threshold entails a certain ‘individualisation’ of the threshold, in that it is determined on the basis of the individual maximum capacity of each network element concerned and according to the number of bidding zones from which loop flows that pass through those network elements originate. 56 However, it must be stated that the ‘individualisation’ referred to in paragraph 55 above is not the individualisation required, in the second subparagraph of Article 16(13) of Regulation 2019/943, by the words ‘for each individual bidding zone border’. 57 The level of loop flows changes according to the characteristics of the bidding zones, such as the size, the degree of meshing, the proportion of electricity injected that comes from renewable energies and the number of borders of the bidding zone concerned. Thus, the level of loop flows may vary from one bidding zone to another, on a ‘border’ within the meaning of Article 16(13) of Regulation 2019/943, or even on the elements of relevance to congestion between two zones. That is why the second subparagraph of Article 16(13) of Regulation 2019/943 requires the threshold to be determined on the basis of the characteristics of the bidding zones in question and the different borders between them. 58 However, ACER’s determination of the threshold is based, in the first stage, on a single threshold for all bidding zones in the Core region, so that no account is taken of the specific characteristics of those zones or of the borders between them. 59 Furthermore, the ‘individualisation’ carried out in the second stage also does not take account of the characteristics of the different bidding zones, but depends solely on the number of bidding zones from which the loop flows that pass through the relevant network elements originate. The same reasoning applies in the event of a subsequent allocation, among the other bidding zones, of the share of the threshold not used by a bidding zone. 60 It follows that the threshold set by ACER does not comply with the requirement laid down in the second subparagraph of Article 16(13) of Regulation 2019/943, according to which the threshold must be defined ‘for each individual bidding zone border’. 61 In the second place, as regards the requirement for the threshold to correspond to the ‘level that could be expected without structural congestion’, it is common ground that the analysis normally required to determine the level of loop flows that could be expected without structural congestion, required by the first subparagraph of Article 16(13) of Regulation 2019/943, was not carried out in the present case. 62 In the absence of such an analysis, the threshold set by ACER cannot comply with the requirement for that threshold to correspond to the level of loop flows that could be expected without structural congestion. 63 In that regard, it is apparent from paragraphs 958 (page 145) and 1221 (page 189) of the contested decision that ACER considered that the threshold which it had set corresponded to a situation without structural congestion. 64 It is apparent from paragraph 115 of Decision No 30/2020 and from paragraph 134 of the defence that ACER consulted with TSOs regarding the level of loop flows that could be expected without structural congestion. While some TSOs indicated values varying between 3, 5 and 10%, others did not respond or indicated thresholds higher than 10%. In those circumstances, and assuming that the TSOs’ responses had been influenced by their own interests, ACER set the threshold at 10% of the maximum capacity of the network element concerned as an ‘average’ of the opinions provided, as is also apparent from paragraph 115 of Decision No 30/2020. 65 It follows that the setting of 10% of the maximum capacity of the network element concerned as a common threshold for all bidding zones of the Core region and as the first stage in the determination of the threshold per network element concerned is not based on any analysis of the threshold without structural congestion, as required by the first subparagraph of Article 16(13) of Regulation 2019/943, but is the result of a compromise with regard to the divergent opinions provided by the TSOs concerned. 66 As ACER acknowledges in paragraph 930 (page 141) of the contested decision, the analysis required by the first subparagraph of Article 16(13) of Regulation 2019/943 presupposes, inter alia, an analysis of network investments and any alternative configurations of bidding zones that would remove structural congestions. ACER admits that it did not carry out such an analysis. 67 In those circumstances, ACER’s argument that its determination of the threshold is based on a ‘rigorous analysis’ is ineffective, since, in any event, that analysis was not the analysis required by Article 16(13) of Regulation 2019/943. 68 It follows that the threshold set by ACER does not comply with the requirements laid down in Article 16(13) of Regulation 2019/943, according to which the threshold must correspond to the ‘level that could be expected without structural congestion’ and must be defined ‘for each individual bidding zone border’. The conditions for recognising implicit competence 69 It follows from the foregoing assessments that ACER’s determination of the threshold in the contested cost sharing methodology does not comply with Article 16(13) of Regulation 2019/943. 70 In those circumstances, the question whether, in principle, ACER was competent to determine a threshold itself on the basis of point (a) of the second subparagraph of Article 6(10) of Regulation 2019/942, as follows from paragraph 924 (page 140) of the contested decision, is irrelevant. That provision cannot, in any event, allow ACER to set a threshold that does not comply with the requirements of Article 16(13) of Regulation 2019/943. 71 It must therefore be examined whether, despite the fact that ACER’s determination of the threshold did not comply with the requirements of Article 16(13) of Regulation 2019/943, ACER had, in the specific situation in which it found itself, an implicit competence authorising it to determine a threshold in a different way than that prescribed by that provision. 72 ACER contends that its competence to determine a threshold is justified by the need for it to act. In the absence of the analysis of the level that could be expected without structural congestion that was to be carried out by the TSOs, ACER was authorised, in order to avoid a deadlock situation, to set a temporary threshold itself in the contested cost sharing methodology. 73 In the first place, it cannot in principle be accepted, in the light of the principle of legality, that an agency of the European Union, such as ACER, may derogate from the applicable legal framework. It follows that ACER could not, in principle, derogate from Article 16(13) of Regulation 2019/943. 74 In the second place, it should be noted that, in accordance with Article 6(12)(b) of Regulation 2019/942, ACER may ‘provide an interim decision to ensure that … operational security is protected’. It must be stated that, in the present case, as the applicant rightly points out, ACER did not rely on that provision to establish the threshold. Furthermore, and in any event, the adoption of the cost sharing methodology cannot be regarded as necessary in order to ‘ensure that security of supply or operational security is protected’, within the meaning of Article 6(12)(b) of Regulation 2019/942. The purpose of that methodology is to share the costs of remedial actions and it is not intended to determine the remedial actions to be taken in order to ensure security of supply or operating security. 75 Moreover, the existence of that provision and, accordingly, of the power to adopt, in clearly defined circumstances, interim decisions militates against recognising that ACER has an implicit competence to set, even temporarily, the threshold in the cost sharing methodology in a different way than that prescribed by Article 16(13) of Regulation 2019/943. 76 In the third place, in accordance with the case-law, mere reliance on an interest linked to effectiveness is insufficient to create a competence on the part of an agency of the European Union (see, to that effect, judgment of 24 October 2019, E-Control v ACER, T‑332/17, not published, EU:T:2019:761, paragraph 69). Mere reliance on an interest linked to effectiveness is therefore insufficient to allow an agency of the European Union to derogate from the applicable legal framework. 77 However, it cannot be ruled out that an interest linked to effectiveness, provided that it corresponds to a real need to ensure the practical effect of the provisions of the Treaties or the regulation concerned, may justify the existence of an implicit decision-making power (see, to that effect, judgment of 24 October 2019, E-Control v ACER, T‑332/17, not published, EU:T:2019:761, paragraph 69). 78 It must therefore be examined whether, in the present case, the conditions for recognising that ACER has implicit competence, in accordance with that case-law, were satisfied. Recognition that ACER has implicit competence 79 In accordance with the case-law cited in paragraph 77 above, in order to determine whether ACER could avail itself of implicit competence, it must be examined whether recognising that ACER has such competence corresponded to a real need to ensure the practical effect of the provisions at issue. 80 In that regard, it is apparent from paragraphs 924 to 946 (pages 140 to 144) and 1206 to 1220 (pages 214 to 216) of the contested decision that ACER claimed that the need to adopt a cost sharing methodology within the prescribed time limit had forced it to set the threshold itself, despite the absence of the analysis normally required. 81 First, as regards the need relied on with regard to the timetable, it is true that ACER was, in principle, required to adopt a cost sharing methodology within the time limit laid down in Article 6(12)(a) of Regulation 2019/942 and Article 9(11) of Regulation 2015/1222, namely a time limit of six months from 27 March 2020. 82 However, EU law does not attach any penalty to exceeding the six-month time limit laid down in Article 6(12)(a) of Regulation 2019/942 and Article 9(11) of Regulation 2015/1222. That time limit is therefore indicative rather than mandatory. 83 In accordance with the case-law, where there is such an indicative time limit, even if the EU body to which that time limit applies must endeavour to comply with it, it may be necessary for it, in particular because of the complexity of the task and provided that the interests of a Member State are not impaired, to have more time (see, to that effect, judgment of 15 January 2013, Spain v Commission, T‑54/11, EU:T:2013:10, paragraph 27). 84 Consequently, the starting point of ACER’s reasoning is incorrect, since it was not mandatory for it to adopt a cost sharing methodology within the prescribed time limit, that is to say, before 28 September 2020. 85 Furthermore, it is common ground that the analysis of the ‘level that could be expected without structural congestion’ is complex and requires a considerable amount of time. 86 It was therefore, in principle, open to ACER to allow the TSOs sufficient time to carry out the analysis required without being criticised for disregarding the time limit laid down in Article 6(12)(a) of Regulation 2019/942 and Article 9(11) of Regulation 2015/1222. 87 That is all the more so since the obligation to determine a threshold by carrying out the analysis provided for in Article 16(13) of Regulation 2019/943 did not enter into force until 1 January 2020. 88 At the time when the TSOs of the Core region submitted their proposal for a cost sharing methodology to all the NRAs of that region for approval, namely on 27 March 2019, Regulation 2019/943 had not yet been adopted. 89 In that regard, it must be stated that neither Decision No 30/2020 nor the contested decision explores the possible consequences, for the timetable for adopting the cost sharing methodology, of the fact that the obligation to determine a threshold and, therefore, to carry out the corresponding analysis did not enter into force until 1 January 2020. 90 Therefore, the Board of Appeal’s assumption in the contested decision that it was necessary for ACER to adopt the contested cost sharing methodology, without being able to wait for the analysis prescribed by Article 16(13) of Regulation 2019/943, owing to the time limit set for it to do so, is based on a reading of the regulatory framework that does not take into account either the indicative nature of the time limit to be observed by ACER or the change in the legal framework in force. 91 Accordingly, mere reliance on an indicative time limit for ACER to adopt the cost sharing methodology is insufficient to demonstrate a real need to ensure the practical effect of the provisions at issue. 92 Second, ACER stated that the need for it to act is justified by the TSOs’ failure to act. It is apparent from paragraph 955 (page 145) of the contested decision that ACER contended that the TSOs had not been able, ‘in a period of nearly 3 years’, to carry out the analysis required by Article 16(13) of Regulation 2019/943. 93 In that regard, it should be recalled that the obligation to determine the threshold by carrying out the analysis prescribed by Article 16(13) of Regulation 2019/943 did not enter into force until 1 January 2020. 94 Moreover, it must be stated that, contrary to what ACER maintains in paragraph 926 (page 140) of the contested decision, the TSOs did not consider it mandatory, in the explanatory document of 22 February 2019 accompanying the proposal for the cost sharing methodology of 27 March 2019, to determine a threshold, but rather perceived that as an option left to them. 95 Even if it were accepted that the need to set a threshold was recognised by the TSOs before the adoption of Regulation 2019/943, the fact remains that Article 16(13) of Regulation 2019/943 specifies how the threshold should be determined, namely on the basis of an analysis of the ‘level [of loop flows] that could be expected without structural congestion’ and ‘for each individual bidding zone border’. 96 ACER does not contend that it was established, before the entry into force of Regulation 2019/943, that the threshold had to be determined in that way. 97 In those circumstances, ACER could not legitimately criticise the TSOs for not being able, ‘in a period of nearly 3 years’, to carry out the analysis required by Article 16(13) of Regulation 2019/943. 98 That conclusion is also not called into question by the documents produced by ACER at the hearing to demonstrate that the TSOs and NRAs of the Core region were still discussing how the analysis required by Article 16(13) of Regulation 2019/943 should be carried out. 99 Irrespective of whether those documents are admissible, it must be stated that the ongoing negotiations relied on by ACER are irrelevant to the present case. 100 According to the case-law, the legality of a decision must be assessed purely on the basis of the elements of fact and of law existing at the time when it was adopted (see judgment of 27 April 2022, Roos and Others v Parliament, T‑710/21, T‑722/21 and T‑723/21, EU:T:2022:262, paragraph 211 and the case-law cited). Thus, the evidence relied on by ACER, which post-dates the contested decision, cannot be taken into account for the purpose of assessing the legality of that decision. 101 Third, ACER contended that the need for it to act is justified by the TSOs’ failure to comply with the time limit that it had set for them. In that regard, it states that it set for the TSOs a time limit of four months, from 18 April to 20 August 2020, to carry out the analysis required by Article 16(13) of Regulation 2019/943 and adds that they did not comply with that time limit. 102 As is apparent from paragraphs 930 (page 141), 954 (page 145) and 1131 (page 202) of the contested decision, ACER itself considered that the analysis prescribed by Article 16(13) of Regulation 2019/943 was complex and would require a considerable amount of time. 103 Moreover, ACER has not demonstrated that, during the four-month time limit that it had set for the TSOs, it facilitated, in one way or another, the work of the TSOs in carrying out the analysis prescribed by Article 16(13) of Regulation 2019/943. 104 In accordance with Article 6(11) of Regulation 2019/942, which reflects the principle of sincere cooperation enshrined in Article 4(3) TEU, ACER is required to consult NRAs and TSOs when preparing a decision on the basis of Article 6(10) of that regulation. 105 In accordance with the principle of sincere cooperation and taking into account the clear intention of the EU legislature to make decision-making on difficult but necessary cross-border issues more efficient and faster (judgment of 7 September 2022, BNetzA v ACER, T‑631/19, EU:T:2022:509, paragraph 46), ACER was to facilitate the development, by the TSOs and NRAs, of the analysis required by Article 16(13) of Regulation 2019/943. 106 In those circumstances, ACER cannot legitimately criticise the TSOs for not being able to carry out the analysis required by Article 16(13) of Regulation 2019/943 within the prescribed time limit, namely four months. 107 Fourth, ACER further contended that the need to adopt the contested cost sharing methodology without being able to wait for the analysis required by Article 16(13) of Regulation 2019/943 is justified by two other considerations. 108 First, at the hearing, ACER contended that it would have been necessary to give the TSOs sufficient time, after the contested cost sharing methodology was adopted, to put in place the necessary arrangements properly to implement it. 109 It should be noted that, according to Article 13(2) of the contested cost sharing methodology, read in conjunction with Article 37(2) of the methodology for coordinated redispatching and countertrading for the Core region (‘the RDCT methodology’), a first step in the implementation of the contested cost sharing methodology was scheduled for 4 June 2023, whereas the full implementation of that methodology was scheduled for 4 June 2025. 110 Thus, given that the contested cost sharing methodology was first to be partially implemented only two and a half years after it was adopted, and fully implemented four and a half years after it was adopted, mere reliance on the need for the TSOs to put in place the necessary arrangements properly to implement that methodology is not sufficient to demonstrate, in the light of the very long period laid down for implementing it, a real need to adopt that methodology without being able to wait for the analysis required by Article 16(13) of Regulation 2019/943. 111 Second, it is apparent from paragraph 946 (page 144) of the contested decision that ACER considers that the contested cost sharing methodology had to be implemented simultaneously with the RDCT methodology and the methodology for regional operational security coordination for the Core region (‘the ROSC methodology’). 112 In that regard, it is sufficient to note that the present case in no way involves deciding whether ACER was authorised to set the same dates for the implementation of the contested cost sharing methodology, the RDCT methodology and the ROSC methodology, but rather determining whether ACER could adopt the contested cost sharing methodology without being able to wait for the analysis required by Article 16(13) of Regulation 2019/943. 113 In those circumstances, the argument based on the alleged need to implement the contested cost sharing methodology, the RDCT methodology and the ROSC methodology simultaneously is irrelevant to the question of when the cost sharing methodology had to be adopted. 114 Accordingly, ACER also could not contend that the need for it to act was justified by considerations relating to the need to allow the TSOs sufficient time to put in place the necessary arrangements properly to implement the contested cost sharing methodology simultaneously with two other methodologies. 115 It follows that ACER has not established that it was necessary to adopt the contested cost sharing methodology without being able to wait for the analysis required by Article 16(13) of Regulation 2019/943. 116 Consequently, ACER has not demonstrated that there was a real need to ensure the practical effect of the provisions at issue that would justify recognising that it has implicit competence. 117 In any event, it must be stated that ACER’s determination of the threshold is not capable of ensuring the practical effect of the provisions at issue. 118 It is true that that determination of the threshold enabled ACER to adopt the contested cost sharing methodology on 30 November 2020, that is to say, slightly after the time limit that had been set for it to do so, which expired on 27 September 2020. However, that did not ensure the practical effect of the substantive provisions at issue. 119 The contested cost sharing methodology must, in accordance with Article 74(6)(a) of Regulation 2015/1222, provide incentives to invest effectively to manage congestion. In addition, according to recital 34 of Regulation 2019/943, the management of congestion should provide correct economic signals to TSOs and market participants. 120 As stated in paragraph 68 above, the threshold determined by ACER, confirmed by the contested decision, does not comply with the requirements of Article 16(13) of Regulation 2019/943, according to which the threshold must correspond to the ‘level that could be expected without structural congestion’ and be defined ‘for each individual bidding zone border’. 121 In those circumstances, on account of that determination of the threshold, the contested cost sharing methodology cannot provide, by means of sharing the costs of remedial actions, ‘correct economic signals’ for network investments. 122 Furthermore, it must also be stated that the weighing-up of the interest in complying with the prescribed time limit and the interest in complying with Article 16(13) of Regulation 2019/943, apparently carried out by ACER, does not justify determining a threshold that does not comply with the relevant legislation. 123 As pointed out in paragraph 82 above, the time limit set for ACER to adopt a cost sharing methodology was merely indicative, so that, in a weighing-up of interests, the intention to comply with that time limit cannot take precedence over compliance with the requirements of Article 16(13) of Regulation 2019/943. 124 That outcome cannot be called into question by ACER’s argument that it determined the threshold only on a temporary basis. The temporary nature of that determination in no way mitigates the breach of the relevant regulatory framework by ACER and the Board of Appeal. 125 The fact that the temporary nature of the determination of the threshold exists only de jure does not make it possible to lessen ACER’s failure to comply with the relevant regulatory framework. 126 Accordingly, ACER cannot justify its approach of giving precedence, in the weighing-up of interests, to the interest in complying with the prescribed time limit over the interest in complying with the requirements of Article 16(13) of Regulation 2019/943 by relying on the temporary nature of the resulting interference with the regulatory framework, through determining a threshold in a way that does not comply with that framework. Consequently, ACER could not base its determination of the threshold on an implicit competence. 127 In the light of the foregoing assessments, it must be concluded that ACER’s determination of the threshold in the contested cost sharing methodology, as confirmed by the contested decision, infringes Article 16(13) of Regulation 2019/943, in that that threshold does not meet the criterion that the threshold must correspond to the ‘level that could be expected without structural congestion’ or the criterion that the threshold must be defined ‘for each individual bidding zone border’. Furthermore, it is apparent from the foregoing that ACER was also not entitled to determine a threshold differently in order to comply with the time limit set for it to adopt the contested cost sharing methodology. 128 In those circumstances, the first and fifth pleas in law must be upheld, without there being any need to examine the other complaints raised by the applicant in support of them. 129 In so far as the first and fifth pleas concern a central element of the contested cost sharing methodology, which is the subject of the contested decision, the Court cannot annul the contested decision only in part. 130 Consequently, the applicant’s action must be upheld on the basis of the first and fifth pleas and the contested decision must be annulled in so far as it confirms Decision No 30/2020 and dismisses the applicant’s appeal in Case A-001-2021 (consolidated). 131 In those circumstances, there is no need to examine the other pleas raised by the applicant. Whether the contested decision should be maintained 132 Under the second paragraph of Article 264 TFEU, the Court may, if it considers it necessary, state which of the effects of the act which it has declared void are to be considered as definitive. 133 In response to measures of organisation of procedure ordered by the Court, the parties submitted their observations in that regard. 134 In the present case, ACER contends that the annulment of the contested decision and, consequently, of the contested cost sharing methodology would have serious consequences. TSOs would have to bear all the costs of all remedial actions activated on their network elements, even if those actions were necessary due to loop flows from other bidding zones. The effect of that situation would likely be that TSOs would have an incentive to limit cross-zonal capacity, resulting in higher electricity prices. 135 In accordance with the case-law, on grounds of legal certainty, the effects of an act may be maintained, in particular, where the immediate effects of its annulment would give rise to serious negative consequences for the persons concerned and where the lawfulness of the act in question is contested not because of its aim or content, but on grounds of lack of competence or infringement of an essential procedural requirement (see judgment of 15 July 2021, Commission v Landesbank Baden-Württemberg and SRB, C‑584/20 P and C‑621/20 P, EU:C:2021:601, paragraph 175 and the case-law cited). 136 In that regard, first, it should be noted that the annulment of the contested decision is based, inter alia, on an infringement of substantive law, namely an infringement of the second subparagraph of Article 16(13) of Regulation 2019/943, and not solely on an infringement of essential procedural requirements. 137 Second, ACER’s line of argument is based on the assumption that the contested cost sharing methodology is already applicable. 138 It is apparent from the parties’ answers to the questions put by the Court that the contested cost sharing methodology, which is the subject of the contested decision, will not be fully implemented before 4 June 2025 and that, on account of delays, its implementation may even be further postponed. 139 In those circumstances, there is no need to limit the effect of the annulment of the contested decision. Costs 140 Under Article 134(1) of the Rules of Procedure of the General Court, the unsuccessful party is to be ordered to pay the costs if they have been applied for in the successful party’s pleadings. 141 Since ACER has been unsuccessful and the applicant has applied for costs, ACER must be ordered to pay the costs. 142 According to Article 138(1) of the Rules of Procedure, the Member States and institutions which have intervened in the proceedings are to bear their own costs. The Republic of Poland must therefore bear its own costs. On those grounds, THE GENERAL COURT (Third Chamber, Extended Composition) hereby: 1. Annuls the decision of the Board of Appeal of the European Union Agency for the Cooperation of Energy Regulators (ACER) of 28 May 2021 in Case A-001-2021 (consolidated), in so far as it confirms ACER Decision No 30/2020 of 30 November 2020 on the proposal of the electricity transmission system operators of the ‘Core’ capacity calculation region, comprising Belgium, the Czech Republic, Germany, France, Croatia, Luxembourg, Hungary, the Netherlands, Austria, Poland, Romania, Slovenia and Slovakia, for the methodology for cost sharing of redispatching and countertrading, and dismisses the applicant’s appeal in that case; 2. Orders ACER to bear its own costs and to pay those incurred by Polskie sieci elektroenergetyczne S.A.; 3. Orders the Republic of Poland to bear its own costs. Schalin Škvařilová-Pelzl Nõmm Steinfatt Kukovec Delivered in open court in Luxembourg on 25 September 2024. V. Di Bucci S. Papasavvas Registrar President * Language of the case: English.