Dimosia Epicheirisi Ilektrismou AE (DEI) v European Commission (T-639/14 R)

Contents

Judgment of the General Court (Third Chamber, Extended Composition)22 September 2021^note(State aid — Tariff for electricity supply — Fixing of the tariff invoiced to Alouminion by decision of an arbitration tribunal — Decision to take no further action on the complaint — Decision finding that there is no aid — Act open to challenge — Interested person status — Interest in bringing proceedings — Locus standi — Admissibility — Whether attributable to the State — Advantage — Private operator principle — Serious difficulties)In Joined Cases T‑639/14 RENV, T‑352/15 and T‑740/17,Dimosia Epicheirisi Ilektrismou AE (DEI), established in Athens (Greece), represented, in Case T‑639/14 RENV, by E. Bourtzalas, A. Oikonomou, E. Salaka, C. Synodinos, H. Tagaras and D. Waelbroeck, in Case T‑352/15, by E. Bourtzalas, C. Synodinos, E. Salaka, H. Tagaras and D. Waelbroeck and, in Case T‑740/17, by E. Bourtzalas, E. Salaka, C. Synodinos, H. Tagaras, D. Waelbroeck, A. Oikonomou and V.-K.-L. Moumoutzi, lawyers,vEuropean Commission, represented, in Case T‑639/14 RENV, by É. Gippini Fournier and A. Bouchagiar and, in Cases T‑352/15 and T‑740/17, by A. Bouchagiar and P.-J. Loewenthal, acting as Agents,Mytilinaios AE – Omilos Epicheiriseon, formerly Alouminion tis Ellados VEAE, established in Marousi (Greece), represented by N. Korogiannakis, N. Keramidas, E. Chrysafis and D. Diakopoulos, lawyers,THE GENERAL COURT (Third Chamber, Extended Composition),composed of A.M. Collins, President, V. Kreuschitz (Rapporteur), Z. Csehi, G. De Baere and G. Steinfatt, Judges,Registrar: S. Spyropoulos, Administrator,having regard to the written part of the procedure and further to the hearing on 8 October 2020,gives the following

Judgment

I. Background to the disputes and procedures

1The present cases concern three closely related disputes which have arisen one after the other and concern essentially the same subject matter, namely the question whether the electricity supply tariff (‘the tariff in question’) which the applicant, Dimosia Epicheirisi Ilektrismou AE (DEI), an electricity producer and supplier established in Athens (Greece) and controlled by the Greek State, must charge, by virtue of an arbitration award, to its largest customer, namely the intervener, Mytilinaios AE, formerly Alouminion tis Ellados VEAE, an aluminium producer, involves the grant of State aid.

2Case T‑639/14 RENV concerns an application by the applicant for annulment of letter COMP/E3/ΟΝ/AB/ark *2014/61460 from the European Commission dated 12 June 2014, signed by a Head of Unit of the Directorate-General (DG) for Competition (‘the contested letter’), informing the applicant, in essence, that no further action would be taken on the complaint it had made on the ground that the tariff in question did not constitute State aid as the criteria relating to whether the measure could be attributable to the State and to whether the measure conferred an advantage on the undertaking were not met. In that complaint, filed on 23 December 2013 (‘the second complaint’), the applicant had disputed Decision No 1/2013 of 31 October 2013 of the special arbitration tribunal (‘the arbitration award’) to which the applicant and the intervener had referred their dispute, under Article 37 of the nomos 4001/2011, gia ti leitourgia Energeiakon Agoron Ilektrismou kai Fysikou Aeriou, gia Erevna, Paragogi kai diktya metaforas Ydrogonanthrakon kai alles rythmiseis (Law No 4001/2011 on the operation of the electricity and gas energy markets, research, production and hydrocarbon transport networks and other regulations) (FEK A’ 179/22.8.2011; ‘Law No 4001/2011’), and by which that tribunal had fixed the tariff in question for the period from 1 July 2010 to 31 December 2013 (‘the period at issue’) at a gross amount of 40.7 EUR/MWh and a net amount of 36.6 EUR/MWh.

3Case T‑352/15 concerns an application by the applicant for annulment of Decision C(2015) 1942 final of 25 March 2015 (Case SA.38101 (2015/NN) (ex 2013/CP) – Greece – Alleged State aid to Alouminion SA in the form of electricity tariffs below cost following an arbitration decision) (‘the first contested decision’), in which the Commission, first, withdrew and replaced the contested letter with that decision and, secondly, took the view that the arbitration award did not involve the granting of State aid to the intervener within the meaning of Article 107(1) TFEU, essentially on the ground that the applicant’s voluntary submission of its dispute with the intervener to arbitration was consistent with the conduct of a prudent investor operating in a market economy and, therefore, did not confer an advantage.

4Case T‑740/17 concerns an application by the applicant for annulment of Decision C(2017) 5622 final of 14 August 2017 (Case SA.38101 (2015/NN) (ex 2013/CP) – Greece – Alleged State aid to Alouminion SA in the form of electricity tariffs below cost following an arbitration decision) (‘the second contested decision’), in which the Commission again decided, while expressly repealing and replacing both the contested letter and the first contested decision (paragraphs 8 and 51 and Section 5 of the second contested decision), that the arbitration award did not involve the granting of State aid within the meaning of Article 107(1) TFEU. The reasons given in support of that conclusion, based on compliance with the prudent private investor operating in a market economy test and lack of an advantage, are identical to those set out in the first contested decision.

5Hereinafter, first, the first and second contested decisions, taken together, will be referred to as ‘the contested decisions’ and, secondly, those decisions, taken together with the contested letter, will be referred to as ‘the contested measures’.

6The present disputes are the continuation of a long-running dispute between the applicant and the intervener regarding the electricity supply tariff intended to replace the preferential tariff stemming from an agreement which was signed in 1960 but which expired in 2006.

7On 4 August 2010, the applicant and the intervener signed a framework agreement concerning the electricity supply tariff to be applied during the period at issue, in addition to the arrangements for the amicable settlement of an alleged debt owed by the intervener to the applicant, which had accrued during the period from 1 July 2008 to 30 June 2010. On the basis of the criteria laid down in that framework agreement, the intervener and the applicant have been unsuccessful in negotiating the content of a draft electricity supply contract.

8After the applicant sent the draft electricity supply contract to the Rythmistiki Archi Energeias (Greek Energy Regulator, Greece; ‘the RAE’), it adopted Decision No 692/2011 (FEK B’ 2529/7.11.2011) on the ‘basic principles for electricity pricing in Greece’. That decision was subsequently incorporated into the Greek Electricity Supply Code (FEK B’ 832/9.4.2013).

9As part of an arbitration agreement signed on 16 November 2011, the intervener and the applicant agreed to entrust the resolution of their dispute to the permanent arbitration body of the RAE, in accordance with Article 37 of Law No 4001/2011. In that regard, the arbitration agreement provides inter alia as follows:‘The parties have agreed to have joint recourse to the arbitration referred to in Article 37 of Law No 4001/2011 so that, in accordance with the basic principles of pricing for high-voltage customers, as set out by the RAE in its Decision No 692[/2011], but also taking into account … Decision No 798[/2011] and … Award No 8/2010 of the arbitration tribunal, the RAE will update and adapt the pricing conditions contained in the draft [electricity supply] contract drawn up on 5 October 2010 with a view to implementing the [framework] agreement, and, in the framework of the [said] decisions …, it will draw up the contractual conditions for supply between the parties which are applicable from 6 June 2011, so that those conditions, first, correspond to [the intervener’s] consumption profile and, secondly, cover at least the costs borne by [the applicant].’

10Following a complaint lodged by the intervener with the RAE under Article 140(6) and Article 35 of Law No 4001/2011, the latter, by Decision No 346/2012 of 9 May 2012 set, on a provisional basis, an electricity supply tariff of 42 EUR/MWh applicable to the intervener.

11In a complaint lodged with the Commission on 15 June 2012 (‘the first complaint’), the applicant submitted, inter alia, that that tariff obliged it to supply the intervener electricity at a price below its costs and thus below the market price and that, therefore, the RAE had granted that company unlawful State aid.

12On 31 October 2013, by the arbitration award, the arbitration tribunal fixed the tariff in question (see paragraph 2 above). Following an action brought by the applicant before the Efeteio Athinon (Court of Appeal, Athens, Greece), that court, by Judgment No 634/2016 of 18 February 2016, upheld that award.

13On 18 December 2013, the intervener lodged a complaint with the Elliniki Epitropi Antagonismou (Greek Competition Commission; ‘the EEA’), claiming that the applicant had abused its dominant position by proposing a new tariff, which was allegedly excessive and discriminatory, from 2013. That complaint led to the adoption by the EEA, on 22 July 2015, of Decision No 621/2015 (FEK B’ 492/26.2.2016) which took the view, provisionally, that the applicant had abused its dominant position to the detriment of the intervener, inter alia, by refusing, unjustifiably, to continue trade relations with it and to sell electricity to it and by having considered imposing on it other trading conditions which were unreasonable or unfair. By decision of 18 January 2016, the EEA accepted the behavioural commitments proposed by the applicant which led to the closure of the complaint.

14On 23 December 2013, the applicant lodged the second complaint with the Commission, claiming that the arbitration award constituted State aid (see paragraph 2 above).

15On 6 May 2014, the Commission sent the applicant its preliminary assessment, according to which there was no need to investigate the second complaint. By letters of 20 May and 6 June 2014, the applicant submitted additional observations to the Commission.

16By the contested letter (see paragraph 2 above), the Commission informed the applicant that it was closing the investigation of its complaint essentially on the following grounds:‘We note that the arguments contained in your letter of 6 June 2014 are not new and [were] taken into account in our preliminary assessment letter of 6 May 2014. Indeed, with your letter of 6 June 2014, you have still not demonstrated that the arbitration tribunal is a body exercising State authority, especially since both [the applicant and the intervener had recourse] voluntarily to the arbitration, without any legal obligation to that end. You also admit that [the applicant] (and therefore the [Greek] State) had various options at its disposal in order to conclude on the tariff that [it] should charge [the intervener]. Given that the arbitration tribunal had a mandate to decide on a tariff, in accordance with the general principles governing the arbitration procedure and taking into consideration decisions and guidelines provided previously by the [RAE] on the subject, the [Greek] State does not seem to have had the possibility to dictate the decision of the arbitration tribunal. Thus, the services of DG Competition reiterate their position as expressed in the letter of 6 May 2014 as regards the fact that the decision of the arbitration tribunal cannot be attributed to the [Greek] State, since you did not provide sufficient evidence to dispute this position.As regards your allegation that the tariff decided by the arbitration tribunal is below the cost of [the applicant], we note that your arguments on the cost methodology are inconsistent with those of the Greek authorities, [the] RAE and the arbitration tribunal decision. Indeed, the arbitration tribunal had a specific mandate to determine a tariff that would cover the costs of [the applicant] and [it] had the opportunity to present its arguments in that context. [That award] explicitly acknowledges that [that] tariff is covering the costs of [the applicant] plus a reasonable profit, while at the same time taking into account the consumer profile of [the intervener]. Thus, the services of DG Competition reiterate their position as expressed in the letter of 6 May 2014 as regards the lack of a selective advantage in the measure in question, since you did not provide sufficient evidence to dispute this position.In light of the above, the services of DG Competition have concluded that the information provided by your letter of 6 June [2014] [did] not provide any evidence which would dispute our preliminary assessment letter of 6 May 2014. We also take note of the fact that you do not provide us with any further or new information which would demonstrate the existence of an infringement of the State aid rules.Thus, the services of DG Competition have concluded that this information [was] not sufficient to justify a further investigation of your complaint.’

17By application lodged at the Registry of the General Court on 22 August 2014, the applicant brought the action registered under number T‑639/14 seeking annulment of the Commission’s decision to close the investigation of its complaints, as contained in the contested letter.

18By letter of 7 October 2014 lodged at the Registry of the General Court, the applicant and the Commission jointly requested, under Article 77(c) of the Rules of Procedure of the General Court of 2 May 1991, a stay of proceedings for a period of six months, thus until 7 April 2015, in order to enable the Commission to re-examine the matters raised in the application. That request was granted by order of the President of the Fourth Chamber of the General Court of 24 October 2014.

19By document lodged at the Registry of the General Court on 19 December 2014, the intervener applied for leave to intervene in support of the form of order sought by the Commission in Case T‑639/14.

20On 25 March 2015, the Commission adopted the first contested decision (see paragraph 3 above).

21In support of the first contested decision, the Commission considered, inter alia, in paragraphs 12 and 13 of that decision, that:‘In the [second] complaint, [the applicant] also refers to [the first complaint]. In this [first] complaint it alleged that Decision 346/2012 by [the RAE], which set an interim tariff for the electricity supplied to [the intervener] for the time until the dispute between those two parties concerning the tariff was settled, obliged [the applicant] to supply electricity to [the intervener] below market prices and, thereby, to grant State aid to [the intervener]. However, as the Arbitration Decision fully and retroactively replaced the interim tariff set by [the RAE], the Commission considers that the [first] complaint … has become without object.Thus, the present decision only assesses the [second] complaint … concerning the question whether any State aid was granted to [the intervener] in the form of electricity tariffs below costs following the arbitration decision.’

22Thus, in its analysis, the Commission confined itself to assessing whether the fixing and implementation of that tariff was consistent with the granting of an advantage to the intervener for the purposes of Article 107(1) TFEU. To that end, it examined whether, by agreeing to settle the dispute with the intervener by having recourse to the arbitration procedure and by complying with the arbitration award, the applicant, in its capacity as a public undertaking, had acted in accordance with the requirements of the private investor test (paragraphs 25 to 47 of the first contested decision). It concluded, first, that the conditions for applying that test were satisfied in the present case and that, therefore, no advantage had been granted to the intervener and, secondly, that, since the first contested decision reflected its final position in that regard, the contested letter had to be regarded as having been replaced by that decision (paragraphs 48 and 49 of that decision).

23The Commission therefore found that the arbitration award did not constitute State aid (Section 4 of the first contested decision).

24By letters of 27 April and 19 June 2015 lodged at the Registry of the General Court, the Commission applied to the General Court for a decision that, following the first contested decision, the action brought against the contested letter had become devoid of purpose and that there was no longer any need to adjudicate on it. The applicant submitted to the General Court its observations on that request by letter of 3 July 2015.

25By application lodged at the Registry of the General Court on 29 June 2015, the applicant brought the action registered under number T‑352/15 for annulment of the first contested decision.

26By document lodged at the Registry of the General Court on 16 November 2015, the intervener applied for leave to intervene in support of the form of order sought by the Commission in Case T‑352/15.

27By order of 9 February 2016, DEI v Commission (T‑639/14, not published, EU:T:2016:77, paragraphs 36 and 37), the General Court decided that there was no longer any need to rule on the action in Case T‑639/14 on the ground, inter alia, that the first contested decision had formally replaced the contested letter, so that that letter ‘[was] no longer part of the EU legal order, in so far as [it] was repealed with effect from the [said] decision’. It also decided that there was therefore no longer any need to rule on the intervener’s application for leave to intervene.

28On 22 April 2016, the applicant brought an appeal before the Court of Justice against that order, registered under number C‑228/16 P.

29By order of 8 June 2016, DEI v Commission (T‑352/15, not published, EU:T:2016:386), the General Court (Fourth Chamber) granted the intervener leave to intervene in Case T‑352/15. The intervener lodged its statement in intervention and the main parties lodged their observations on that statement within the period prescribed.

30By judgment of 31 May 2017, DEI v Commission (C‑228/16 P, EU:C:2017:409, paragraphs 44 and 46), the Court of Justice set aside the order of 9 February 2016, DEI v Commission (T‑639/14, not published, EU:T:2016:77), referred the case back to the General Court and reserved the costs.

31Following the delivery of that judgment, Case T‑639/14, now numbered T‑639/14 RENV, was allocated to the Fifth Chamber of the General Court to which the Judge-Rapporteur was assigned.

32By letter of 27 July 2017 lodged at the Registry of the General Court, the applicant requested that Cases T‑639/14 RENV and T‑352/15 be joined for the purposes of the oral part of the procedure. By letter of 21 August 2017, the Commission agreed to such a joinder.

33On 14 August 2017, the Commission adopted the second contested decision (see paragraph 4 above).

34By letters of 24 August 2017 lodged at the Registry of the General Court, thus following the adoption of the second contested decision, the Commission applied to the General Court for a decision, in accordance with Article 130 of the Rules of Procedure of the General Court, that the actions in Cases T‑639/14 RENV and T‑352/15 had become devoid of purpose and that there was no longer any need to adjudicate on them. By letter of 27 October 2017, the intervener declared that it supported the Commission’s application for a declaration that there was no need to adjudicate in Case T‑352/15. By letters of the same date, the applicant stated that it objected to a declaration that there was no need to adjudicate in those cases.

35By application lodged at the Registry of the General Court on 3 November 2017, the applicant brought an action registered under number T‑740/17 for annulment of the second contested decision.

36On 21 December 2017, by way of measures of organisation of procedure, the General Court asked the parties about a possible stay of proceedings in Cases T‑639/14 RENV and T‑352/15 pending the completion of the written part of the procedure in Case T‑740/17. By letters of 4 and 8 January 2018, the Commission and the applicant stated respectively that they did not object to the proceedings being stayed.

37By document lodged at the Registry of the General Court on 12 March 2018, the intervener applied for leave to intervene in support of the form of order sought by the Commission in Case T‑740/17.

38By orders of 14 May 2018, the General Court ordered that the Commission’s applications for a declaration that there was no need to adjudicate be reserved for the final judgment and reserved the costs in Cases T‑639/14 RENV and T‑352/15.

39By order of 12 July 2018 the President of the Fifth Chamber of the General Court granted the intervener leave to intervene in Case T‑740/17. The intervener lodged its statement in intervention and the main parties lodged their observations on that statement within the period prescribed.

40By decision of 13 July 2018, only the proceedings in Case T‑352/15 were stayed pending the completion of the written part of the procedure in Case T‑740/17.

41By order of 25 September 2018 in Case T‑639/14 RENV, the President of the Fifth Chamber of the General Court granted the intervener leave to intervene in Case T‑639/14. The intervener lodged its statement in intervention and the main parties lodged their observations on that statement within the period prescribed.

42By decision of the President of General Court of 28 February 2019, under Article 27(3) of the Rules of Procedure, Cases T‑639/14 RENV, T‑352/15 and T‑740/17 were assigned to a new Judge-Rapporteur sitting in the Third Chamber.

43On 28 March 2019, acting on a proposal from the Judge-Rapporteur, the General Court asked the parties to express their views on a possible joinder of Cases T‑639/14 RENV, T‑352/15 and T‑740/17 for the purposes of the oral part of the procedure and the final decision. By letters of 4 April 2019, the Commission agreed to the joinder of those cases, without requesting confidential treatment of certain documents in the files. By letters of 25 April 2019, the applicant expressed its disagreement with the joinder of Case T‑639/14 RENV with Cases T‑352/15 and T‑740/17 and requested that it be dealt with separately, without, however requesting confidential treatment of certain documents in the files.

44Following a change in the composition of the Chambers of the General Court, pursuant to Article 27(5) of the Rules of Procedure, the Judge-Rapporteur was assigned to the Third Chamber, to which the present cases were consequently allocated.

45On a proposal from the Third Chamber, the General Court decided, pursuant to Article 28 of the Rules of Procedure, to refer the case to a formation sitting with a greater number of Judges.

46By decision of the President of the Third Chamber (Extended Composition) of 26 February 2020, Cases T‑639/14 RENV, T‑352/15 and T‑740/17 were joined for the purposes of the oral part of the procedure and the decision which closes the proceedings, in accordance with Article 68 of the Rules of Procedure.

47Acting on a proposal from the Judge-Rapporteur, the General Court (Third Chamber, Extended Composition) decided to open the oral part of the procedure.

48By letter of 3 June 2020, the intervener submitted observations on the report for the hearing which were placed on file and served on the other parties.

49Following the applicant’s request to postpone the hearing initially scheduled for 11 June 2020 on the ground that its staff lawyers, namely A. Oikonomou, E. Salaka and C. Synodinos, would be prevented from attending due to the ban on all foreign travel issued by the ‘hierarchical authority’ of DEI to its employees because of the health crisis, the General Court, by way of measures of organisation of procedure provided for in Article 89 of the Rules of Procedure, put a written question to the applicant concerning the existence of any employment relationship between itself and those salaried lawyers and their authorisation to represent it in the present proceedings, asking it to reply in writing. The applicant replied to that question within the prescribed period.

50By letter of 29 September 2020, the applicant submitted observations on the report for the hearing containing eight annexes, the decision on their inclusion in the file being reserved.

51By letter of 5 October 2020, the intervener submitted further observations on the report for the hearing which were placed on file and served on the other parties.

52The parties presented oral argument and answered the questions put to them by the General Court at the hearing on 8 October 2020. At the hearing, the President decided that the applicant’s observations on the report for the hearing should be placed on file and served on the other parties and that a time limit should be set for them to submit their observations, which was noted in the minutes of the hearing.

53As the oral part of the procedure was left open following the hearing, the Commission and the intervener submitted their observations within the prescribed period and, in the light of Article 85 of the Rules of Procedure, challenged the admissibility of the applicant’s observations on the report for the hearing. including the annexes thereto. Following the decision of the President of the Chamber to close the oral part of the procedure, by separate document lodged at the Registry of the General Court on 12 January 2021, the applicant requested that the Court reopen the oral part of the procedure in order to enable it to comment on those observations by the Commission and the intervener, by way of an exchange of arguments.

II. Forms of order sought by the parties

A. Case T‑639/14 RENV

54The applicant claims that the Court should:– annul the contested letter in so far as it contains the decision to reject its complaints;– order the Commission to pay the costs.

55The Commission contends that the Court should:– principally, declare that there is no need to adjudicate;– in the alternative, dismiss the action as inadmissible, or otherwise as unfounded;– order the applicant to pay the costs.

56The intervener submits that the Court should:– dismiss the action;– order the applicant to pay the costs, including those incurred by the intervener.

B. Case T‑352/15

57The applicant claims that the Court should:– annul the first contested decision;– order the Commission to pay the costs.

58The Commission and the intervener contend that the Court should:– principally, declare that there is no need to adjudicate;– in the alternative, dismiss the action as inadmissible, or otherwise as unfounded;– order the applicant to pay the costs.

C. Case T‑740/17

59The applicant claims that the Court should:– annul the second contested decision;– order the Commission to pay the costs.

60The Commission contends that the Court should:– dismiss the action as inadmissible, or otherwise as unfounded;– order the applicant to pay the costs.

61The intervener submits that the Court should:– dismiss the action;– order the applicant to pay the costs, including those incurred by the intervener.

III. Law

A. Preliminary observations

62As a preliminary point, it should be noted that, for the purposes of resolving the disputes, there is no need to determine whether the applicant’s ‘salaried lawyers’, namely A. Oikonomou, E. Salaka and C. Synodinos, are, under the applicable Greek legislation, authorised to represent it in the present proceedings (see paragraph 49 above), since that representation is ensured, sufficiently, by E. Bourtzalas, H. Tagaras, D. Waelbroeck and V.-K.-L. Moumoutzi.

63Moreover, it is appropriate to assess the action in Case T‑740/17 first, since its outcome is likely to have an impact on the purpose of the disputes and the applicant’s interest in bringing proceedings in Cases T‑639/14 RENV and T‑352/15 being maintained.

B. Case T‑740/17

1. Admissibility

64The Commission, supported by the intervener, submits that the action is inadmissible on the ground that, first, that the applicant is neither directly nor individually concerned by the second contested decision, secondly, in the absence of binding legal effects vis-à-vis the applicant, that decision cannot be the subject of an action for annulment, and, thirdly, the applicant has not established any interest in bringing the proceedings.

65In the first place, the Commission submits, in essence, that the applicant does not have the status of a party ‘concerned’ in accordance with Article 108(2) TFEU or an ‘interested party’ within the meaning of Article 1(h) of Council Regulation (EU) 2015/1589 of 13 July 2015 laying down detailed rules for the application of Article 108 [TFEU] (OJ 2015 L 248, p. 9). Neither the fact of being a complainant or having participated in the administrative procedure, nor that of being obliged to grant the alleged aid from its own funds would be sufficient for that purpose; the applicant should rather have demonstrated its status as a competitor of the intervener, as the alleged recipient undertaking, which it did not do. The same applies to being the ‘pot from which resources are taken to finance the alleged … aid’, since a Member State’s cost savings or safeguarding the soundness of the public sector are not, as such, an objective pursued by the rules on State aid.

66According to the Commission, supported by the intervener, a fortiori, the applicant has not demonstrated that the alleged aid has had a significant effect on its market position, and therefore the pleas seeking to call into question the merits of the second contested decision are inadmissible. It states in essence that that alleged aid relates to the relationship pursuant to which the applicant supplies electricity to the intervener, namely a customer relationship and not a competitive relationship between those undertakings. The intervener’s economic activity and the effect of the tariff in question on its competitive position are said to fall within the scope of the metallurgy sector, which is not relevant in the present case, since the applicant is active in the electricity production or supply sector. Moreover, as the applicant itself acknowledges, the first, second and fourth to seventh pleas in law concerning the ‘infringement of Articles 107 and 108 TFEU’ do not refer to any serious difficulties. Finally, according to the Commission, the applicant is also not distinguished individually in its capacity as the provider of the alleged aid, in so far as it cannot be treated in the same way as a local authority which acted in the exercise of its legislative and fiscal autonomy.

67In the second place, the Commission considers that the second contested decision is not capable of forming the subject matter of an action for annulment brought by the applicant on the ground that that decision does not produce binding legal effects likely to affect its interests by bringing about a distinct change in its legal position as the de facto provider of the alleged aid. It states that that decision is not binding on the Greek State since it concludes that the tariff in question falls outside the scope of Article 107 TFEU. However, the obligation on the applicant to apply that tariff is said to derive from its voluntary commitment to comply with the arbitration award and not from that decision. According to the Commission, the decision in question gives full satisfaction to the Greek State in that it guarantees the Greek authorities the freedom to implement the tariff in question without triggering the procedure in respect of existing aid. The applicant, as a public undertaking which has granted the alleged aid, does not belong to the category of applicants entitled to bring an action against such a decision.

68In the third place, the Commission, supported by the intervener, considers that the applicant has no interest in bringing proceedings against the second contested decision. It states that that decision gives it full satisfaction as the entity granting the alleged aid and the obligation to grant aid to the intervener derives exclusively from the arbitration award. In its view, the interest which the applicant seeks to protect does not fall within the objectives pursued by the rules on State aid and its approach is contrary to the purpose of Articles 107 and 108 TFEU, which are based on the logic that the entity granting the aid wishes to have the greatest possible leeway in that regard. It compares the applicant’s strategy with that of a local authority which has signed a contract considered to be no longer profitable and alleges that it is State aid in order to release itself from its commitment. Such conduct is contrary, inter alia, to the legal principle that no one may rely on their own wrongdoing (nemo auditur propriam turpitudinem allegans or venire contra factum proprium). The intervener states that the applicant wrongly and improperly relies on an interest of a ‘private’ nature that is not protected by Article 108 TFEU, that is to say its own financial interests and not its status as a ‘State’ which alone is capable of granting unlawful State aid. It states that the applicant seeks to create confusion between, on the one hand, its ownership by the Greek State which, as its majority shareholder, regularly approves its tariffs for high-voltage customers and, on the other, its ‘private’ interest in order to establish its interest in bringing proceedings while maintaining its erroneous argument as to the existence of aid.

69The applicant disputes the arguments put forward by the Commission and the intervener and considers that the present action is admissible.

70It is necessary to assess, first, whether the second contested decision constitutes a challengeable act, next, whether the applicant has an interest in bringing proceedings and, finally, whether it has standing to bring proceedings under the fourth paragraph of Article 263 TFEU.

71In the first place, according to settled case-law, any measures adopted by the institutions of the European Union, whatever their form, which are intended to have binding legal effects, are regarded as ‘actionable measures’, within the meaning of Article 263 TFEU. In order to ascertain whether or not a measure which has been challenged produces such effects it is necessary to look to its substance. Those effects must be assessed in accordance with objective criteria, such as the contents of that measure, taking into account, as appropriate, the context in which it was adopted and the powers of the institution which adopted the measure (see, to that effect, judgments of 13 February 2014, Hungary v Commission, C‑31/13 P, EU:C:2014:70, paragraphs 54 and 55 and the case-law cited, and of 25 October 2017, Romania v Commission, C‑599/15 P, EU:C:2017:801, paragraphs 47 and 48). Moreover, where an action for annulment is brought by a natural or legal person, as in the present case, the binding legal effects of the contested measure must be capable of affecting the interests of the applicant by bringing about a distinct change in its legal position (see, to that effect, judgment of 13 October 2011, Deutsche Post and Germany v Commission, C‑463/10 P and C‑475/10 P, EU:C:2011:656, paragraph 37 and the case-law cited).

72In the present case, the second contested decision is a decision finding that State aid does not exist, for the purposes of Article 4(2) of Regulation 2015/1589, the binding legal force of which in respect of those to whom it is addressed within the meaning of the fourth paragraph of Article 288 TFEU, in this case the Hellenic Republic, is not in doubt.

73In that regard, the Commission and the intervener argue unsuccessfully that the second contested decision produces no legally binding effects on the applicant.

74It is settled case-law that Article 15(1) of Regulation 2015/1589 obliges the Commission, once additional comments have been lodged by interested parties or the reasonable period has expired, to close the preliminary examination stage by adopting a decision pursuant to Article 4(2), (3) or (4) of that regulation, that is to say, a decision stating that aid does not exist, as in the present case, or raising no objections, or initiating the formal investigation procedure (see, to that effect, judgments of 17 July 2008, Athinaïki Techniki v Commission, C‑521/06 P, EU:C:2008:422, paragraphs 37 to 40; of 16 December 2010, Athinaïki Techniki v Commission, C‑362/09 P, EU:C:2010:783, paragraph 63; and of 31 May 2017, DEI v Commission, C‑228/16 P, EU:C:2017:409, paragraph 29). It necessarily follows that such a decision entails binding legal effects for the purposes of the fourth paragraph of Article 288 TFEU also in respect of such an interested party.

75Moreover, in applying that case-law to the facts giving rise to Case T‑639/14 RENV, the Court of Justice held that, by the adoption of the contested letter, the Commission had closed the file, deciding to close the preliminary examination procedure triggered by the applicant’s complaint, had held that in the inquiry opened it was not possible to conclude that there had been aid within the meaning of Article 107 TFEU and, accordingly, had refused to initiate the formal investigation procedure provided for under Article 108(2) TFEU. In its view, the Commission therefore adopted a definitive position on the applicant’s request for a finding of infringement of Articles 107 and 108 TFEU. It stated that, as the contested letter prevented the applicant from submitting its observations in a formal investigation procedure, that letter produced binding legal effects capable of affecting the applicant’s interests. It concluded that that decision constituted an act open to challenge for the purposes of Article 263 TFEU (see, to that effect, judgment of 31 May 2017, DEI v Commission, C‑228/16 P, EU:C:2017:409, paragraphs 30 and 31 and the case-law cited).

76It must be noted that the same applies to the second contested decision, which, in the Commission’s own words, is intended to replace both the contested letter and the first contested decision.

77That assessment is not called into question by the arguments put forward by the Commission and the intervener.

78First, the Commission has no basis for relying, in support of its line of argument, on the case-law pursuant to which the challengeable nature of an act presupposes that it is intended to have legal effects capable of affecting the interests of the applicant by bringing about a distinct change in his or her legal position (see judgment of 17 July 2008, Athinaïki Techniki v Commission, C‑521/06 P, EU:C:2008:422, paragraph 29 and the case-law cited), since that line of argument disregards the case-law recalled in paragraph 75 above, and the fact that, for the purposes of closing the applicant’s complaint, the second contested decision refuses the applicant’s request to investigate whether the tariff in question involved the granting of an advantage and, therefore, to classify the outcome of the arbitration procedure as an aid measure.

79Secondly, the Commission and the intervener cannot reasonably claim that the applicant is not a ‘party concerned’ or an ‘interested party’ whose legal position is not affected because it is not protected by State aid law, on the ground that, inter alia, the second contested decision, in fact, gives full satisfaction to the Greek State with which the applicant is conflated on account of its status as a public undertaking controlled by the Greek authorities.

80In accordance with the concept of ‘interested party’ referred to in Article 1(h) of Regulation 2015/1589, in its judgment of 31 May 2017, DEI v Commission (C‑228/16 P, EU:C:2017:409, paragraphs 29 to 31), the Court proceeds from a broad concept of ‘interested party’ which includes anyone whose interests might be affected by the granting of aid, including the complainant whose complaint gave rise to the initiation of the preliminary examination stage. In the present case, it has thus pointed out that the contested letter produced binding legal effects capable of affecting the applicant’s interests by preventing it from submitting its observations in a formal investigation procedure, under Article 108(2) TFEU, which necessarily implies that it has recognised its status as a party concerned for the purposes of that provision. That assessment applies mutatis mutandis to the second contested decision which is said to have replaced the contested letter. Therefore, the argument that, in its judgment, the Court of Justice did not examine whether the applicant was a party concerned must be rejected.

81That assessment is supported by the case-law in accordance with which the concept of parties concerned within the meaning of Article 108(2) TFEU is to be interpreted broadly (judgment of 14 November 1984, Intermills v Commission, 323/82, EU:C:1984:345, paragraph 16). Similarly, the use of the expression ‘in particular’ in Article 1(h) of Regulation 2015/1589 indicates that that provision contains only a non-exhaustive list of the persons who may be classified as interested parties, and therefore that concept covers an indeterminate group of addressees (see, to that effect, judgment of 13 June 2019, Copebi, C‑505/18, EU:C:2019:500, paragraph 34 and the case-law cited). Thus, it has been held that that provision did not rule out the possibility that an undertaking which was not a direct competitor of the beneficiary of the aid could be categorised as an interested party, provided that that undertaking demonstrated that its interests could be adversely affected by the grant of the aid and that, to that end, it was sufficient for it to establish, to the requisite legal standard, that the aid was likely to have a specific effect on its situation (see, to that effect, judgment of 24 May 2011, Commission v Kronoply and Kronotex, C‑83/09 P, EU:C:2011:341, paragraphs 63 to 65 and the case-law cited).

82Therefore, the argument put forward by the Commission and the intervener that persons who are not in a competitive relationship with the alleged recipient of the aid in question should be excluded from the concept of parties concerned must be rejected.

83On the contrary, in order to qualify as interested parties, it is sufficient for persons to claim that their interests might be affected by the granting of that aid (see paragraph 81 above). That applies in the present case since, first, according to the applicant, the arbitration award fixing the tariff in question obliges it to grant unlawful aid to the intervener while at the same time causing it financial losses and, secondly, because of the closure of the file on its complaint by, inter alia, the second contested decision, it is denied the opportunity to submit its observations in that regard in the context of a formal investigation procedure.

84It follows that, in so far as the applicant claims, under Article 24(2), read in conjunction with the first subparagraph of Article 12(1) and Article 15(1) of Regulation 2015/1589, that the tariff in question constitutes aid which is prohibited by Article 107(1) TFEU and which affects its economic interests, it has the status of an ‘interested party’ within the meaning of Article 1(h) of that regulation or a ‘party concerned’ in accordance with Article 108(2) TFEU which is prevented by the contested measures, pursuant to which no further action is to be taken on its complaints, from submitting its observations in a formal investigation procedure.

85The arguments put forward by the Commission and the intervener that the second contested decision does not affect the applicant’s legal position or its interests, as an interested party, must therefore be rejected.

86In the second place, according to settled case-law, including in the field of State aid, an action for annulment brought by a natural or legal person is admissible only in so far as that person has an interest in having the contested measure annulled. Such an interest requires that the annulment of that measure must be capable, in itself, of having legal consequences and that the action may therefore, through its outcome, procure an advantage to the party which brought it. In addition, that interest must be vested and current and is to be assessed as at the date on which the action is brought (see, to that effect, judgments of 17 September 2015, Mory and Others v Commission, C‑33/14 P, EU:C:2015:609, paragraphs 55 and 56, and of 7 November 2018, BPC Lux 2 and Others v Commission, C‑544/17 P, EU:C:2018:880, paragraphs 28 and 29 and the case-law cited).

87In the present case, the Commission and the intervener call into question whether the applicant has an interest in bringing proceedings by essentially putting forward the same grounds as those relied on in support of their unfounded argument that the second contested decision is not a challengeable act.

88However, it is apparent from the considerations set out in paragraphs 71 to 85 above that the applicant’s action is directed against an act which adversely affects it by affecting its legal position and its interests and that, therefore, its annulment is liable to procure an advantage for it, albeit because it is likely, under the first paragraph of Article 266 TFEU, to lead the Commission to initiate the formal investigation procedure in accordance with Article 108(2) TFEU.

89In that regard, the arguments put forward by the Commission and the intervener, alleging confusion between the Greek State and the applicant in order to attribute to it the alleged satisfaction of the Greek authorities with the outcome of the arbitration procedure and the comparison of the applicant’s position with that of a local authority cannot succeed. The applicant has set out in detail the reasons why it considers that, first, its economic situation was affected by the arbitration award in so far as it required it to charge the intervener for the supply of electricity a rate below its production costs and, secondly, the contested acts deciding that no further action be taken on its complaints prevented it from submitting its observations in a formal investigation procedure under Article 108(2) TFEU. In the light of those arguments, it follows from the case-law referred to in paragraphs 74 and 75 above that any annulment, inter alia, of the second contested decision on the ground that the Commission was faced with doubts or serious difficulties as to the existence of State aid is capable of procuring an advantage for the applicant precisely because it is such as to require the Commission to initiate the formal investigation procedure, in the context of which it could rely on the procedural guarantees conferred on it under Article 108(2) TFEU (see, to that effect, judgment of 20 June 2019, a&o hostel and hotel Berlin v Commission, T‑578/17, not published, EU:T:2019:437, paragraph 52).

90In that regard, the argument put forward by the Commission and the intervener that the binding legal effects adversely affecting the applicant are attributable not to the second contested decision, but to the arbitration award, cannot be accepted since that decision rejects the applicant’s request that the outcome of the arbitration procedure be classified as an aid measure and the applicant specifically accuses the Commission of having unlawfully failed to investigate, in that decision, whether the tariff in question involved the granting of an advantage (see paragraph 78 above). That assessment is unaffected by the fact that the applicant voluntarily referred the dispute with the intervener to arbitration, since that step does not necessarily imply its prior agreement with the outcome of that arbitration, as is moreover demonstrated by the fact that it unsuccessfully challenged that award before the Efeteio Athinon (Court of Appeal, Athens).

91Nor is the Commission justified in invoking an infringement of the principle of law that no one may rely on his or her own wrongdoing. That argument is merely a further variant of the argument intended to conflate the applicant’s situation with that of the Greek State and to attribute to it any satisfaction on the part of the Greek authorities with the outcome of the arbitration procedure; it cannot therefore be upheld either. For the same reasons, the intervener’s argument, that the applicant wrongly and improperly relies on an alleged ‘private (financial) interest’ which is not protected by State aid law on the ground that its interests overlap with those of the Greek State which controls it, must be rejected.

92Consequently, it must be concluded that the applicant has proved its interest in bringing proceedings against the second contested decision.

93In the third place, with regard to the applicant’s standing to bring proceedings under the fourth paragraph of Article 263 TFEU, it should be recalled that the Commission, supported by the intervener, disputes that the applicant is directly and individually concerned, in accordance with that provision, by the second contested decision, in particular on the ground that the applicant is neither an ‘interested party’ nor a competitor of the intervener, whose market position is liable to be substantially affected by the alleged aid.

94For the reasons set out in paragraphs 79 to 84 above, the arguments put forward by the Commission and the intervener seeking to call into question the applicant’s status as an interested party or party concerned must be rejected at the outset. The applicant must therefore be regarded as such an interested party for the purposes of determining its standing.

95In accordance with settled case-law, for the admissibility of an action brought against a decision adopted under Article 4(2) or (3) of Regulation 2015/1589 to be acknowledged, it is sufficient for the applicant to be an ‘interested party’ who, by its action, is seeking to obtain protection of its procedural rights which it would enjoy following the initiation of a formal investigation procedure under Article 108(2) TFEU. More specifically, in the context of an action brought against such a decision, its lawfulness depends on whether there are serious difficulties in determining the existence of State aid or doubts as to the compatibility of such aid with the internal market which must trigger the initiation of a formal investigation procedure in which the interested parties referred to in Article 1(h) of that regulation can participate. Consequently, an interested party within the meaning of that provision is directly and individually concerned by such a decision on the ground that, as a party to whom the procedural guarantees under Article 108(2) TFEU and Article 6(1) of that regulation apply, it is able to ensure that those guarantees are respected only if it has the possibility of challenging that decision before the EU judicature. Thus, in accordance with that case-law, the specific status of an interested party within the meaning of Article 1(h) of that regulation, in conjunction with the specific subject matter of the action, is sufficient to distinguish individually, for the purposes of the fourth paragraph of Article 263 TFEU, the applicant contesting a decision adopted under Article 4(2) or (3) of the same regulation (see, to that effect and by analogy, judgments of 24 May 2011, Commission v Kronoply and Kronotex, C‑83/09 P, EU:C:2011:341, paragraphs 47 and 48 and the case-law cited, and of 20 June 2019, a&o hostel and hotel Berlin v Commission, T‑578/17, not published, EU:T:2019:437, paragraph 41).

96Where, as in the present case, those conditions are met, it is therefore not necessary to examine the very controversial issue between the parties as to whether the applicant may be classified as a competitor of the intervener in order to give it standing to bring proceedings under the fourth paragraph of Article 263 TFEU. It is only if the applicant calls into question the merits of the contested decision as such that the mere fact that it may be regarded as ‘concerned’ within the meaning of Article 108(2) TFEU cannot suffice to render the action admissible and that it must then demonstrate that it has a particular status within the meaning of the judgment of 15 July 1963, Plaumann v Commission (25/62, EU:C:1963:17, p. 108), and, in particular, that its market position is substantially affected by the aid to which that decision relates (see, to that effect, judgment of 13 December 2005, Commission v Aktionsgemeinschaft Recht und Eigentum, C‑78/03 P, EU:C:2005:761, paragraph 37).

97The case-law has also made clear that, where an applicant seeks the annulment of a decision adopted under Article 4(2) or (3) of Regulation 2015/1589, it essentially contests the fact that that decision was adopted without that institution initiating the formal investigation procedure, thereby acting in breach of the applicant’s procedural rights. In support of such an action, the applicant may rely on any plea in law capable of showing that the assessment of the information and evidence which the Commission had or might have had at its disposal during the preliminary examination stage should have given rise to serious difficulties in determining the existence of State aid or raised doubts as to the compatibility of such aid with the internal market, without having the consequence of changing the subject matter of the action or altering the conditions of its admissibility. On the contrary, according to that case-law, the existence of such doubts is precisely the evidence which must be adduced in order to show that the Commission was required to initiate the formal investigation procedure under Article 108(2) TFEU and Article 6(1) of Regulation 2015/1589 (see, to that effect and by analogy, judgments of 24 May 2011, Commission v Kronoply and Kronotex, C‑83/09 P, EU:C:2011:341, paragraph 59 and the case-law cited; of 3 September 2020, Vereniging tot Behoud van Natuurmonumenten in Nederland and Others v Commission, C‑817/18 P, EU:C:2020:637, paragraph 81; and of 20 June 2019, a&o hostel and hotel Berlin v Commission, T‑578/17, not published, EU:T:2019:437, paragraphs 45 and 46).

98Therefore, in the case of an action challenging the legality of a decision adopted under Article 4(2) or (3) of Regulation 2015/1589, without initiating the formal procedure, it is necessary, in principle, to examine all the complaints and arguments raised by the applicant in the context of the pleas in law relied on, in order to assess whether those pleas make it possible to identify serious difficulties or doubts, on account of which, if present, the Commission should have been required to open that procedure (see, to that effect, judgment of 20 June 2019, a&o hostel and hotel Berlin v Commission, T‑578/17, not published, EU:T:2019:437, paragraphs 45, 46 and 49 and the case-law cited).

99In the present case, the Commission disputes that the present action seeks only to raise doubts and to safeguard the procedural guarantees afforded to the applicant in the context of a formal investigation procedure under Article 108(2) TFEU. It states, in essence, that, in reality, the pleas for annulment relied on in support of that action are intended to call into question the merits of the second contested decision, and therefore the applicant should have demonstrated its standing to bring an action in accordance with the judgment of 15 July 1963, Plaumann v Commission (25/62, EU:C:1963:17, p. 108) and, in particular, a significant effect on its market position as a competitor undertaking.

100It is true that, unlike the applications in Cases T‑639/14 RENV and T‑352/15, the application in Case T‑740/17 does not contain a separate introductory section before the pleas for annulment stating the purpose of the present action which is to rely on the existence of ‘doubts’ or ‘serious difficulties’. The fact remains that paragraphs 35 and 36 of the latter application refer to the case-law on ‘serious difficulties’ in the context of admissibility. Moreover, the second and fourth to seventh pleas for annulment contain similar explicit references stating that they are intended to demonstrate the existence of ‘[serious] doubts’ or ‘serious difficulties’ which should have led the Commission to initiate the formal investigation procedure (see paragraphs 65, 91, 116, 129, 143, 148, 163, 187, 205 and 225 of that application). The fact that a similar clarification is lacking in the first and third pleas does not invalidate that assessment, since those pleas in law, namely the alleged failure to comply, first, with the requirements arising from the judgment of 31 May 2017, DEI v Commission (C‑228/16 P, EU:C:2017:409), and, secondly, the obligation to state reasons and to examine the case diligently and comprehensively, are essentially formal and procedural in nature and are specifically linked to the Commission’s duty to state the reasons for the absence of doubts as to the existence of State aid or of serious difficulties in the examination of the case.

101In the light of the foregoing considerations, it must be concluded that the present action is admissible in so far as it seeks to safeguard the procedural guarantees which the applicant would enjoy, as an interested party, if a formal investigation procedure were to be initiated under Article 108(2) TFEU.

102In that regard, the pleas for annulment relied on must be regarded as seeking to establish the existence of doubts within the meaning of Article 4(3) and (4) of Regulation 2015/1589 or serious difficulties within the meaning of the case-law (see, to that effect, judgments of 12 February 2008, BUPA and Others v Commission, T‑289/03, EU:T:2008:29, paragraph 328, and of 9 September 2020, Kerkosand v Commission, T‑745/17, EU:T:2020:400, paragraph 106) which should have led the Commission to open the formal investigation procedure. In that context, in the light of the case-law referred to in paragraph 97 above, it is irrelevant that some of those pleas are formulated in terms of (manifest) infringement of a rule of law or contain complaints seeking a finding that there has been a (manifest) error of assessment, since the recognition of such an infringement or such an error necessarily implies the recognition of the existence of doubts or serious difficulties (see, to that effect, judgment of 22 September 2011, Belgium v Deutsche Post and DHL International, C‑148/09 P, EU:C:2011:603, paragraphs 58 to 66).

103Consequently, it must be concluded that the applicant has proved its standing to bring proceedings under the fourth paragraph of Article 263 TFEU and that the action must be declared admissible without there being any need to examine whether the second contested decision constitutes a ‘regulatory act’.

2. Substance

(a)The pleas for annulment and the scope of the review of substantive legality

104In support of the present action, the applicant raises seven pleas for annulment.

105In the first plea, the applicant complains that the Commission misinterpreted the judgment of 31 May 2017, DEI v Commission (C‑228/16 P, EU:C:2017:409).

106In the second plea, the applicant accuses the Commission of having failed to fulfil its obligations under Article 24(2) of Regulation 2015/1589 and, in particular, of having infringed its right to be heard as guaranteed by Article 41(2)(a) of the Charter of Fundamental Rights of the European Union.

107In the third plea, the applicant alleges inadequate and contradictory reasoning and a breach of the obligation to examine the relevant matters of fact and of law with respect to the finding that, inter alia, the arbitration agreement set ‘clear and objective parameters’.

108By the fourth plea, the applicant relies on a ‘manifest’ error of law in the application of the principle of the prudent private investor and in the interpretation of Articles 107(1) and 108(2) TFEU in respect of the finding that the tariff in question was a ‘logical consequence’ of those parameters.

109By the fifth plea, the applicant alleges, first, a ‘manifest’ error of law in the interpretation and application of Articles 107 and 108 TFEU vitiating the finding that the Commission did not have to engage in complex economic assessments and, secondly, a ‘manifest’ error of law and a manifest error of assessment of the facts in that it failed to examine crucial evidence in order to establish the existence of State aid.

110By the sixth plea, the applicant submits that the Commission infringed Article 107(1) and Article 108(2) TFEU by committing manifest errors of assessment with respect to the facts relating to the applicability of the test of the prudent private investor operating in a market economy (first part) and the application of that test (second part).

111By the seventh plea, the applicant accuses the Commission of having committed a manifest error in the interpretation and application of Article 107(1) TFEU, of having infringed its obligation to state reasons and of having committed a manifest error of assessment of the facts by not further investigating its first complaint pursuant to Article 108(2) TFEU on the ground that it had become devoid of purpose following the arbitration award.

112As regards the scope of the review of legality which the General Court is called upon to perform in this respect, it should be recalled that Article 108(3) TFEU and Article 4 of Regulation 2015/1589 provide for a stage at which the aid measures notified undergo a preliminary examination. On completion of that stage, the Commission is to make a finding either that the measure does not constitute aid or that it falls within the scope of Article 107(1) TFEU. In the latter case, it may be that the measure does not raise doubts as to its compatibility with the internal market; on the other hand, it is also possible that the measure may raise such doubts (see, to that effect, judgment of 24 May 2011, Commission v Kronoply and Kronotex, C‑83/09 P, EU:C:2011:341, paragraph 43).

113When, after the preliminary examination stage, the Commission adopts a decision whereby it finds that a State measure does not constitute aid that is incompatible with the internal market, it also implicitly refuses to initiate the formal investigation procedure. That principle applies both where the decision is taken on the ground that the Commission considers that the aid is compatible with the internal market, under Article 4(3) of Regulation 2015/1589, namely ‘a decision not to raise objections’, and where it is of the opinion, as in the present case, that the measure does not come within the scope of Article 107(1) TFEU and thus does not constitute State aid pursuant to Article 4(2) of that regulation (see, to that effect, judgments of 16 March 2021, Commission v Poland, C‑562/19 P, EU:C:2021:201, paragraph 50 and the case-law cited, and of 19 June 2019, Ja zum Nürburgring v Commission, T‑373/15, EU:T:2019:432, paragraph 111 and the case-law cited).

114However, it is settled case-law that, if the Commission is unable to conclude, following an initial examination in the context of the procedure under Article 108(3) TFEU, that the State measure in question either is not ‘aid’ within the meaning of Article 107(1) TFEU, or, if classified as aid, is compatible with the FEU Treaty, or where that procedure has not enabled it to overcome all the serious difficulties involved in assessing the compatibility of the measure under consideration, the Commission is under a duty to initiate the formal investigation procedure provided for in Article 108(2) TFEU, without having any discretion in that regard. That obligation corresponds to that laid down in Article 4(4) of Regulation 2015/1589, under which Commission is required to initiate the procedure provided for in Article 108(2) TFEU where the measure at issue raises doubts as to its compatibility with the internal market (see, to that effect and by analogy, judgment of 22 December 2008, British Aggregates v Commission, C‑487/06 P, EU:C:2008:757, paragraphs 113 and 185 and the case-law cited; order of 25 June 2019, Fred Olsen v Naviera Armas, C‑319/18 P, not published, EU:C:2019:542, paragraph 30; and judgment of 20 June 2019, a&o hostel and hotel Berlin v Commission, T‑578/17, not published, EU:T:2019:437, paragraph 57).

115The concept of serious difficulties coincides with that of doubts (see, to that effect, judgments of 12 February 2008, BUPA and Others v Commission, T‑289/03, EU:T:2008:29, paragraph 328, and of 9 September 2020, Kerkosand v Commission, T‑745/17, EU:T:2020:400, paragraph 106) and is objective in nature. The existence of such difficulties must be looked for not only in the circumstances in which the Commission’s decision was adopted after the preliminary investigation but also in the assessments upon which the Commission relied. It follows that the lawfulness of a decision not to raise objections, based on Article 4(3) of Regulation 2015/1589, depends on the question whether the assessment of the information and evidence which the Commission had or might have had at its disposal during the preliminary investigation phase of the measure notified should objectively have raised doubts as to the compatibility of that measure with the internal market, given that such doubts must lead to the initiation of a formal investigation procedure in which the interested parties referred to in Article 1(h) of that regulation may participate (see, to that effect, judgments of 3 September 2020, Vereniging tot Behoud van Natuurmonumenten in Nederland and Others v Commission, C‑817/18 P, EU:C:2020:637, paragraphs 79 and 80 and the case-law cited, and of 20 June 2019, a&o hostel and hotel Berlin v Commission, T‑578/17, not published, EU:T:2019:437, paragraph 58 and the case-law cited).

116The case-law has also made it clear in that regard that the lawfulness of such a decision had to be assessed in the light of the information available to the Commission at the time when the decision was adopted, since the information ‘available’ to it was that which seemed relevant to the assessment to be carried out and which could have been obtained, upon request by the Commission, during the preliminary examination stage (see, to that effect, judgment of 20 September 2017, Commission v Frucona Košice, C‑300/16 P, EU:C:2017:706, paragraphs 70 and 71).

117The onus is on the applicant to prove the existence of serious difficulties or doubts, proof that can take the form of a consistent body of evidence, inter alia, by pointing to and establishing the insufficient or incomplete nature of the examination conducted by the Commission during the preliminary examination procedure (see, to that effect, judgments of 3 September 2020, Vereniging tot Behoud van Natuurmonumenten in Nederland and Others v Commission, C‑817/18 P, EU:C:2020:637, paragraph 82 and the case-law cited, and of 20 June 2019, a&o hostel and hotel Berlin v Commission, T‑578/17, not published, EU:T:2019:437, paragraphs 59 and 60 and the case-law cited).

118In the light of the concepts of doubts or serious difficulties within the meaning of the case-law referred to in paragraphs 112 to 116 above, the third to fifth pleas in law must be examined together, since they seek to challenge the second contested decision for failing to respond adequately to the applicant’s complaints, even though those complaints alleged that the arbitration award, in so far as it fixed the tariff in question, granted an advantage to the intervener which did not correspond to market conditions and nonetheless for having refused to initiate the formal investigation procedure.

(b)The third to fifth pleas in law

(1)Summary of the main arguments of the parties in the context of the third plea in law

119In support of the third plea, alleging inadequate and contradictory reasoning and a breach of the obligation to examine the relevant matters of fact and of law, the applicant submits, in essence, that, in paragraph 48 of the second contested decision, the Commission misinterpreted the wording of the second complaint, which did not concern the question whether its decision to refer the dispute to arbitration constituted State aid, but whether the tariff in question imposed by the arbitration award constituted such aid. In the absence of a sufficient account of the assessment of the relevant issues of fact and law and the reasons for the change in the Commission’s approach compared with that followed in Commission Decision 2010/460/EC of 19 November 2009 on State aid measures C 38/A/04 (ex NN 58/04) and C 36/B/06 (ex NN 38/06) implemented by Italy for Alcoa Trasformazioni (notified under document C(2009) 8112) (OJ 2010 L 227, p. 62; ‘the Alcoa decision’), the second contested decision is said to be vitiated by inadequate and contradictory reasoning. According to the applicant, by failing to verify the validity of the method of calculation and the amount of the tariff in question and by merely concluding that the applicant had acted as a prudent private investor, having regard to the parameters which led it to refer the dispute to arbitration, the Commission departed substantially from its approach in recital 154 of the Alcoa decision without giving specific reasons for that change.

120According to the applicant, paragraph 43 of the second contested decision wrongly states that the arbitration agreement, on the basis of which the arbitration tribunal had to ‘update’ and ‘adjust’ the draft electricity supply contract and thus arrive at the applicable tariff conditions, established ‘clear and objective parameters’, even if a sufficient statement of reasons would have required a careful and serious assessment of those parameters. It observes that paragraph 42 of that decision merely refers to the ‘Basic Principles for Pricing of Electricity to High-Voltage Customers’ and to the fact that, according to the arbitration agreement, the arbitration award had to ensure that the tariff conditions corresponded not only to the characteristics of the intervener’s consumption, but also covered ‘at least’ its costs. It disputes the ‘clear and objective’ nature of those parameters, in the light, inter alia, of the need to determine the tariff conditions using an arithmetic calculation and the use of the vague expression ‘at least’. Even if the interpretation of those criteria were not ambiguous, the way in which they should be combined is said to still be entirely unclear and subjective. Moreover, the applicant points out that, in the arbitration agreement, it and the intervener expressed their disagreement as to whether or not the arbitration tribunal should take into account Award No 8/2010 and whether it should ‘update’, ‘adjust’ or ‘establish’ the tariff conditions for the period before or after 6 June 2011. Thus, far from having had ‘clear and objective parameters’ available to it, the arbitration tribunal is alleged to have relied on texts whose interpretation afforded much uncertainty and discretion. According to the applicant, the Commission failed to carry out a diligent analysis of those parameters and to explain sufficiently its analysis that they were ‘clear and objective’. A fortiori, insufficient reasons are given for the allegation that those ‘clear and objective parameters [limited] the discretion of the arbitrators’ (paragraphs 39 and 42 of the second contested decision). The Commission did not specify whether that ‘limitation’ was the immediate consequence of those parameters or that they excluded the existence of discretion on the part of the arbitration tribunal, or how that discretion was limited.

121According to the applicant, the claim in paragraph 45 of the second contested decision that the tariff in question was the ‘logical consequence’ of the parameters in question is vitiated by a total lack of reasoning. It states that such a claim is incompatible inter alia with the analysis that it acted as a prudent private investor by referring the dispute to arbitration. It considers that it is impossible to classify a decision to resort to arbitration as prudent if the outcome is announced in advance as being unfavourable to the party that took that decision, namely, in the present case, the fixing of a tariff which does not cover its costs. The second contested decision is therefore said to contain a clear contradiction in reasoning, which further highlights the Commission’s obligation to examine the substance of the question of whether the tariff in question constituted State aid.

122The Commission, supported by the intervener, contends that the majority of the applicant’s arguments seek to call into question the merits of the reasoning set out in the second contested decision and are therefore ineffective and must be rejected. According to the Commission, the applicant misinterprets the Alcoa decision, in which it did not adopt the method of ‘time-weighted average prices’ as a generally applicable method for determining the market price for the supply of electricity. It submits that, even though it was not required to make the reasoning set out in paragraphs 23 to 49 of the second contested decision compatible with the Alcoa decision, that is the case here. The applicant’s arguments seeking to challenge, inter alia, the clear and objective nature of the parameters in question does not relate to a failure to state reasons but expresses its disagreement with the reasons for the second contested decision. In any event, the statement of reasons for that decision has enabled the applicant to challenge the merits of the decision and the General Court to exercise its power of review. It states that, in paragraphs 26 to 38 of the second contested decision, the reasons why the applicant’s decision to refer the dispute to arbitration was rational for a private investor are set out at length.

(2)Summary of the main arguments of the parties in the context of the fourth plea in law and the first and second parts of the fifth plea in law

123By the fourth plea, the applicant accuses the Commission of having erred in law in the interpretation and application of the principle of the prudent private investor and in the interpretation of Articles 107(1) and 108(2) TFEU, in addition to manifest errors of assessment of the facts by concluding that the tariff in question, as determined by the arbitration award, was the ‘logical consequence of properly defined parameters in the Arbitration Agreement’.

124According to the applicant, in essence, neither paragraph 42 of the second contested decision nor the arbitration agreement or Decisions No 692/2011 and No 798/2011 of the RAE specify ‘clear and objective parameters’ limiting the arbitrators’ discretion, or information making it possible to determine either the characteristics of the intervener’s consumption, including the method for calculating the supply costs borne by it as far as those characteristics are concerned, or its costs and high and low tariff hours, and even less so a calculation of all the elements constituting the total actual costs incurred by it in connection with that supply, in order to be able to conclude that the tariff in question was the ‘logical consequence’ of those characteristics. It claims, in particular, that the Commission does not explain why that tariff could result from the ‘basic principles for pricing’ since the method and data used to calculate it go beyond the framework of Decision No 692/2011 which takes into account only the costs of electricity production from lignite, which are calculated incorrectly, without including the costs resulting from the supply of electricity on the mandatory wholesale market. It states that it submitted to the Commission the calculation of the tariff resulting from its actual costs, namely 72.42, 80.55 and 77.33 EUR/MWh for the years 2011, 2012 and 2013 respectively. Similarly, for those years, a calculation made either according to the method followed by the majority of the arbitration tribunal, namely on the basis of the costs of production from lignite (62.06, 61.74 and 71.37 EUR/MWh respectively), or according to the method of the time-weighted average price from the mandatory wholesale market (69.10, 72.77 and 75.13 EUR/MWh respectively), which it considers to be the most appropriate, would result in significantly higher tariffs if the correct information on its costs was used.

125The applicant concludes from this that the Commission committed an error of law and a manifest error of assessment and, therefore, ought to have encountered serious difficulties in its evaluation and initiated the formal investigation procedure under Article 108(2) TFEU.

126In the first and second parts of the fifth plea in law, the applicant complains, in essence, that the Commission misapplied the private investor test by failing to assume the role of the arbitration tribunal and carry out complex economic assessments for the purposes of applying that test and ascertaining whether the tariff in question corresponded to normal market conditions.

127According to the applicant, the Commission committed a ‘manifest’ error of law in the interpretation and application of Articles 107 and 108 TFEU by taking the view that it did not have to engage in complex economic assessments in order to determine whether the tariff in question involved the granting of State aid. It considers that the Commission was wrong to take the view that it did not have to verify whether that tariff was ‘in line with market conditions’, in particular whether it covered its costs and, for the purposes of that assessment, it could not take the place of the arbitration tribunal.

128The Commission is said to have committed a ‘manifest’ error of law by taking the view that it could not ‘substitute itself a posteriori’, like a court of last instance, for the assessment of the arbitration tribunal with regard to the calculation of the tariff in question. In the second contested decision, the Commission acknowledged that the arbitration tribunal was a judicial authority, but did not repeat the incorrect assertion made in the contested letter that the arbitration award was not attributable to the Greek State. That assessment is said to be confirmed, inter alia, by the fact that the arbitration tribunal at the RAE, under Article 37 of Law No 4001/2011, must be classified as a State court for the purposes of Article 267 TFEU. That error is said to be all the more manifest in the light of the other possible means of redress, namely either recourse to the ordinary courts or attempting to reach an amicable settlement. The applicant submits that, in each of those cases, the Commission was not able to confine itself to examining the question as to whether the applicant had acted as a private investor by choosing one of those means of redress, but should have examined the outcome of the procedure chosen. Consequently, it considers that the Commission should also have experienced serious difficulties in respect of the question as to whether the tariff in question covered its costs at the very least and was in line with market conditions.

129With regard to the fourth plea in law, the Commission, supported by the intervener, contends, in essence, that it rightly found that the arbitration agreement contained clear and objective parameters (paragraphs 20 to 22 and 42 of the second contested decision). It disputes that the test of the prudent private investor can be met only if the parameters of the arbitration agreement were established to such a point that the appropriate tariff automatically follows from it. Had that been the case, the applicant and the intervener would have had no reason to refer the dispute to arbitration, rather they would have been able to agree directly on that tariff. Moreover, the Commission considers that it is perfectly logical and foreseeable that matters referred to arbitration are interpreted differently. The second contested decision therefore rightly concluded that, in the arbitration agreement, the applicant had accepted clear and objective parameters for determining the tariff to be paid in the same way as a private investor would have done and that the logical consequence of those parameters was the fixing of the tariff in question by the arbitration award. In view of the long-standing dispute between the applicant and the intervener which led to arbitration on the basis of those parameters, the Commission therefore considers that it would have been called upon to assess whether the applicant had acted as a prudent private investor, or even as a private vendor or creditor (paragraphs 34 and 36 to 38 of the second contested decision), in order to conclude that no advantage was granted to the intervener on account of the fact that the tariff in question was consistent with normal market conditions.

130The Commission states that the applicant merely asked that it recalculate the tariff in question on the basis of information and methods which it itself considers to be correct, which renders the private investor test nugatory. Since the applicant voluntarily agreed, in the same way as a private investor, to refer the dispute to arbitration and signed the arbitration agreement containing the parameters in question, the outcome of that arbitration, namely the tariff in question, can only be in line with market conditions as it follows logically from the parameters of the arbitration agreement. In reality, the applicant is not asking for State aid law to be applied, but for the case brought before the arbitration tribunal to be re-examined, even though it was unsuccessful in the same way as a private investor in the same situation. The Commission therefore maintains that it correctly applied the prudent private investor test and Article 107(1) and Article 108(2) TFEU by taking the view that the outcome of the arbitration and therefore the tariff in question was in line with market conditions as the logical consequence of the clear and objective parameters of the arbitration agreement.

131The intervener states, in essence, that the arbitration agreement is the result of the applicant’s free will, following lengthy negotiations with the intervener, and was approved by the applicant’s legal department, Board of Directors and general meeting, and therefore its complaints are incorrect and contrary to the general principle of law that none may rely to their advantage on their own omission or illegality (nemo auditur propriam turpitudinem allegans). It states that that agreement contains clear and objective parameters which reasonably define the scope of the arbitration tribunal’s power and the guidelines on which the arbitration award was to be based and refers to Decision No 692/2011 of the RAE which sets out, in a comprehensive, exhaustive and binding manner, the basic principles for pricing, without the applicant having brought an action against it before the Greek courts. It submits that the content of that decision was approved by the Commission and the Hellenic Republic as the basis for setting the applicable tariffs under the conditions of the liberalised electricity market and was incorporated into the Electricity Supply Code on the basis of which the applicant undertook, with the EEA, to negotiate with it. Moreover, the intervener states that Decision No 798/2011 of the RAE is an ad hoc decision on the draft electricity supply contract between the applicant and itself containing detailed instructions relating to the conditions authorised in such a contract. Lastly, it notes that, in accordance with Decision No 692/2011, it and the applicant agreed that the conditions for the supply of electricity had to correspond to its consumption profile and cover at least the costs borne by the applicant. It concludes from this that the arbitration agreement was sufficiently clear and objective to define the mandatory parameters for setting a reasonable price and supply conditions which any prudent entrepreneur, in his or her capacity as a seller or buyer of electricity, would have required in order to ensure a fair assessment by the arbitration tribunal. In particular, the applicant cannot claim that the tariff in question was lower than its costs, since it failed to present its cost elements before the arbitration tribunal, in its complaints and in the course of the proceedings. It states that, in any event, the tariff in question was, admittedly, lower than that requested by the applicant, but also higher than that requested by the intervener, and therefore both parties were on an equal footing. That is corroborated by the fact that, under the supply contract signed for the period starting on 1 July 2016, the applicant accepted an even lower tariff than that fixed by the arbitration award, namely at a rate of 32 EUR/MWh.

132With regard to the first and second parts of the fifth plea in law, the Commission submits, in essence, that it did not take the view, in the second contested decision, that it did not have to engage in complex economic assessments.

133According to the Commission, the rule pursuant to which it had to assess whether there was an economic advantage was the prudent private investor test. Since the applicant agreed to refer the dispute to arbitration in the same way as a private investor would have done in the circumstances of the present case, no advantage has been granted to the intervener. In such a case, the outcome of the arbitration, namely the tariff in question, would have been the same for the intervener, even if a private investor had acted in the applicant’s place, and would necessarily have been obtained under normal market conditions. In the light of its arguments referred to in paragraph 130 above, the Commission considers that it rightly found, first, in paragraph 44 of the second contested decision, that it was not necessary to determine whether the tariff in question was in line with market conditions in order to conclude that the intervener had not received an advantage and, secondly, in paragraph 45 of that decision, that it did not need to enter into every detail of the calculation of that tariff. In its view, the fact that the applicant behaved like a private investor vis-à-vis the intervener has no bearing on the question whether the arbitration tribunal fixed the tariff in question on the basis of information and methods which the applicant considers to be correct, since it may disagree with the arbitration award, like any other private investor who has been unsuccessful. It states that it is contradictory for the applicant to argue that a tariff was ‘imposed’ on it by the arbitration award, even though it signed the arbitration agreement which forms the basis of its free will, as a private contractor.

134The Commission considers that the application of the private investor test does not presuppose that the applicant has decided to refer the dispute to arbitration on the basis of a prior economic study comparing the economic advantage associated with arbitration to that associated with recourse to other available means to resolve the dispute. Many economic decisions are essentially based on qualitative assessments, such as, in the present case, the need to resolve the dispute quickly, and not on the quantitative assessments of an economic study regarding the future profitability of a company following a capital injection. The private investor test requires such a prior study only for transactions and operations for which prudent private investors would normally request it, which is not the case when recourse is had to arbitration, as in the present case.

135According to the Commission, in view of the fact that the private investor test was met and, therefore, that no advantage was granted to the intervener, it had no reason to assume the role of the arbitration tribunal a posteriori. By contrast, it considers that, where a decision of an arbitration tribunal or an ordinary State court involves the granting of State aid, it is competent to adopt a negative decision which takes precedence over such a decision. Moreover, the applicant’s arguments regarding the status of the arbitration tribunal and the question whether the arbitration award could be attributed to the Greek State are ineffective since the second contested decision is based only on the lack of an advantage. In any event, the question whether an arbitration tribunal may be regarded as a State tribunal for the purposes of Article 267 TFEU is irrelevant to the existence of such an advantage.

136According to the Commission, the complaints that it failed to examine the applicable regulatory framework, the organisation and functioning of the market, the importance of the intervener’s consumption profile, the elements of DEI’s costs and the methodology used to determine its costs, and the complaint that the arbitration tribunal incorrectly calculated the tariff in question, are directed exclusively against the arbitration award, without, however, showing that the applicant did not act as a private investor. It states that the second contested decision was, however, based on the application of the private investor test in order to conclude that no advantage was granted. In any event, that decision is said to reflect an examination of the relevant factors in that regard by taking into account, as an illustration, first, the regulatory framework for the electricity market in Greece (paragraphs 18, 20, 21, 29, 33, 37, 40 and 41 and footnotes 5, 6 and 13 to 18), secondly, the intervener’s consumption profile (paragraph 31 and footnote 3), thirdly, the characteristics of the applicant as an electricity producer and supplier (paragraph 30 and footnote 7), and, fourthly, the general circumstances of the dispute between the applicant and the intervener (Sections 2.1 and 2.2 and paragraphs 34 to 38 and 42). However, the applicant did not call into question the assessment of those parameters in the context of the application of the private investor test, but only the tariff in question. The Commission concludes that it has examined the outcome of the arbitration in the light of all the circumstances of the case.

137The intervener disputes the attempt to convert the Commission and the General Court into bodies with the power to review the arbitration award. The applicant has not established that it did not behave like a private investor, either when it decided to refer the dispute to arbitration under the conditions of the arbitration agreement, or during the arbitration proceedings. Moreover, that award set a much higher tariff than that considered by the intervener to be fair and equitable. Given that, under Greek law, an arbitration award is regarded as equivalent to a judicial decision and is enforceable, it has waived the right to challenge the arbitration award before the competent courts.

(3)Assessment of the General Court

(i)Summary of the relevant considerations set out in the second contested decision

138With regard to the application of the private operator principle (see judgment of 6 March 2018, Commission v FIH Holding and FIH Erhvervsbank, C‑579/16 P, EU:C:2018:159, paragraph 45 and the case-law cited) and the existence of an advantage which is the subject of the third, fourth and fifth pleas in law, it is clear from paragraphs 37 to 48 of the second contested decision that the Commission considered that, in the light of the circumstances underlying the dispute between the applicant and the intervener, the fact that it was long-standing and the unlikelihood of the applicant succeeding before ordinary courts within an acceptable period of time, a prudent market economy operator would, in DEI’s position, have opted for arbitration in order to recover at least part of the outstanding debt and would have agreed to the applicable tariff being set by an arbitration tribunal composed of experts whose discretion is limited by parameters comparable to those contained in the arbitration agreement (paragraphs 37 to 39 of that decision).

139In that regard, the Commission emphasised the expertise and independence of the experts (paragraphs 40 and 41 of the second contested decision) and the predefined clear and objective parameters governing the determination of the tariff in question and limiting the discretion of the arbitrators, that is the pricing principles applicable to high-voltage customers on the Greek energy market, on which the RAE would also have relied if it had had to set tariffs for the supply of electricity on the basis of regulatory measures, and the need to have regard to the intervener’s consumption profile and the applicant’s cost structure (paragraph 42 of that decision).

140The Commission concluded, in essence, that a prudent private investor in the applicant’s position would have entered into an arbitration agreement with those features, and therefore the criteria of that agreement were in line with market conditions and did not have the effect of granting an advantage to the intervener (paragraph 43 of the second contested decision).

141In paragraphs 44 to 48 of the second contested decision, the Commission stated that, in those circumstances, it was not necessary to determine whether the precise level of the tariff resulting from the arbitration award was in line with market conditions. The outcome of the arbitration was said to comply with the private investor test where the parameters agreed for setting that tariff were pre-determined on the basis of objective market-based criteria, with the result that such an investor would have agreed to refer the dispute to arbitration in the circumstances of the present case. Nor was it necessary to make complex economic assessments regarding the precise calculation of the tariff in question by assuming the role of the arbitration tribunal, since that tariff was in line with market conditions as the logical consequence of pre-defined parameters in the arbitration agreement. In that regard, the Commission recalled that the applicant had signed that agreement without calling those parameters into question for being contrary to market conditions. Moreover, it states that account must be taken of the fact that a prudent private investor would not be able to influence the outcome of an arbitration procedure conducted on the basis of those parameters, aside from the possibility of challenging that award before an ordinary court. Furthermore, the tariff in question is still higher than the average electricity tariffs applied to undertakings in the metal sector in Europe in 2013.

142In the light of the third and fourth pleas in law and the first and second parts of the fifth plea, it is necessary to assess whether the Commission was justified, first, in confining itself to applying the private operator principle to the applicant’s decision to refer the dispute to arbitration by signing the arbitration agreement and, secondly, in refraining from establishing whether, by fixing the tariff in question, the arbitration award involved the granting of an advantage to the intervener which did not correspond to normal market conditions, without giving rise to any doubts or serious difficulties in assessing the existence of State aid within the meaning of Article 107(1) TFEU. To that end, it is necessary to recall, first, the division of powers and obligations between the Commission and the national courts in that regard, in view of the possible need to treat the arbitration tribunal in the same way as a national court.

(ii)The division of powers and obligations between the Commission and the national courts

143The implementation of the State aid control system is a matter, first, for the Commission and, second, for the national courts, each of which fulfil complementary but distinct roles. Although national courts do not have jurisdiction to rule on the compatibility of State aid with the internal market, as that supervision falls within the exclusive competence of the Commission, they ensure the safeguarding, until the final decision of the Commission, of the rights of individuals faced with a possible breach by State authorities of the prohibition laid down by Article 108(3) TFEU. For this purpose, proceedings may be commenced before national courts requiring those courts to interpret and apply the concept of ‘State aid’, contained in Article 107(1) TFEU, in particular in order to determine whether a measure introduced without observance of the preliminary examination procedure provided for in Article 108(3) TFEU ought to have been subject to this procedure (see, to that effect, judgments of 15 September 2016, PGE, C‑574/14, EU:C:2016:686, paragraphs 30 to 32; of 26 October 2016, DEI and Commission v Alouminion tis Ellados, C‑590/14 P, EU:C:2016:797, paragraphs 95 to 98 and the case-law cited; and of 23 January 2019, Fallimento Traghetti del Mediterraneo, C‑387/17, EU:C:2019:51, paragraphs 54 and 55 and the case-law cited).

144If the national courts reach the conclusion that the measure at issue should have in fact been notified to the Commission, they must ascertain whether the Member State concerned has fulfilled that obligation and, if that is not the case, declare that measure unlawful. It is for those courts to draw all the necessary inferences from the infringement of Article 108(3) TFEU, in accordance with domestic law, with regard both to the validity of the acts giving effect to the aid and the recovery of financial support granted in disregard of that provision (see, to that effect, judgment of 26 October 2016, DEI and Commission v Alouminion tis Ellados, C‑590/14 P, EU:C:2016:797, paragraphs 99 and 100 and the case-law cited).

145Moreover, the application of the State aid rules is based on a duty of sincere cooperation between national courts, on the one hand, and the Commission and the EU Courts, on the other, in the context of which each acts on the basis of the role assigned to it by the FEU Treaty. In the context of that cooperation, national courts must take all the measures, whether general or specific, necessary to ensure fulfilment of the obligations under EU law and must refrain from those that may jeopardise the attainment of the objectives of the Treaty, as follows from Article 4(3) TEU. Accordingly, national courts must, in particular, refrain from taking decisions that conflict with a decision of the Commission (see, to that effect, judgments of 15 September 2016, PGE, C‑574/14, EU:C:2016:686, paragraph 33, and of 26 October 2016, DEI and Commission v Alouminion tis Ellados, C‑590/14 P, EU:C:2016:797, paragraph 105 and the case-law cited).

146It follows that, on the basis of the direct effect of the third sentence of Article 108(3) TFEU, read in conjunction with the concept of aid within the meaning of Article 107(1) TFEU, the national courts, alongside the Commission which acts under the supervision of the EU Courts, play a complementary role for the purposes of the effective enforcement of State aid law, inter alia, by ensuring that the national authorities comply with it.

147Conversely, national courts are themselves liable to disregard their obligations under Articles 107(1) and 108(3) TFEU and, in so doing, to make possible or perpetuate the granting of unlawful aid, or even to become the instrument for the grant of such aid. The Court of Justice has held that the suspension, as an interim measure and ex nunc, of the effects of the termination of a long-term contract for the supply of electricity at a preferential rate by a national court hearing an application for interim measures may constitute an infringement of the obligation to notify and of the prohibition on implementing aid under the third sentence of Article 108(3) TFEU by (see, to that effect, judgment of 26 October 2016, DEI and Commission v Alouminion tis Ellados, C‑590/14 P, EU:C:2016:797, paragraphs 107 and 108). Similarly, where a national court perpetuates the granting of unlawful aid, or even makes it possible to implement it notwithstanding the existence of a final decision of the Commission declaring that aid incompatible with the internal market, in the light of the principle of primacy, the application of a rule which seeks to lay down the principle of res judicata in respect of the judicial decision in question must be excluded (see, to that effect, judgments of 18 July 2007, Lucchini, C‑119/05, EU:C:2007:434, paragraphs 61 to 63; of 11 November 2015, Klausner Holz Niedersachsen, C‑505/14, EU:C:2015:742, paragraphs 41 to 45, and of 4 March 2020, Buonotourist v Commission, C‑586/18 P, EU:C:2020:152, paragraphs 94 and 95).

148The Court has stated in that regard that, where there is a decision of a national court relating to a State measure prior to the Commission decision, that situation does not prevent the Commission from exercising the exclusive jurisdiction conferred on it by the FEU Treaty as regards the assessment of the compatibility of aid measures with the internal market. The exercise of such a power implies that the Commission may examine, pursuant to Article 108 TFEU, whether a measure constitutes State aid which should have been notified to it, in accordance with paragraph 3 of that article, in a situation where the authorities of a Member State have taken the view that that measure did not satisfy the conditions laid down in Article 107(1) TFEU, including where those authorities have complied, in that regard, with the assessment of a national court (see, to that effect, judgment of 4 March 2020, Buonotourist v Commission, C‑586/18 P, EU:C:2020:152, paragraphs 92 and 93).

149In the light of those case-law principles, it is necessary to examine whether the arbitration tribunal must be classified as a body which is akin to an ordinary Greek court, the assessment of which should have been verified by the Commission in order to be able to remove any doubts or serious difficulties as to whether the tariff in question involved an advantage for the purposes of Article 107(1) TFEU.

(iii)The existence of an economic advantage for the intervener

–The public nature of the arbitration tribunal

150It must be stated that the situation as described in paragraph 148 above corresponds to that in the present case, apart from the fact that the arbitration award is a decision adopted by an arbitration tribunal and not a decision by an ordinary State court.

151First, in the present case, by the arbitration award, the arbitration tribunal took a legally binding decision on the fixing of the tariff in question which was capable of procuring an advantage for the intervener in the event that it did not correspond to normal market conditions and, therefore, of constituting State aid which has not been notified by the Hellenic Republic under Article 108(3) TFEU. Secondly, the evidence provided by the applicant, which is not contested by the Commission and only the minor details of which are contested by the intervener, establishes that the arbitration tribunal, as established by the RAE under Article 37 of Law No 4001/2011, the arbitration proceedings conducted before it, and its decisions, have characteristics similar to those of ordinary Greek courts, the disputes brought before them and their decisions.

152That is apparent, inter alia, from the following criteria.

153First, the arbitration tribunals established under Article 37 of Law No 4001/2011 perform a judicial function which is identical to that of the ordinary courts, or even replace those courts in so far as the opening of arbitration proceedings deprives them of their jurisdiction.

154Secondly, the arbitrators, selected from a list drawn up by decision of the President of the RAE, must demonstrate their independence and impartiality before their appointment (Article 37(4) of Law No 4001/2011 and Article 6(1) and (2) of the RAE’s arbitration rules).

155Thirdly, proceedings before arbitration tribunals are governed, inter alia, by the provisions of the Kodikas politikis dikonomias (Greek Code of Civil Procedure) and, in addition, by the RAE’s arbitration rules (RAE Decision No 261/2012, part 1, preamble).

156Fourthly, the decisions of the arbitration tribunals are legally binding, have the force of res judicata (Article 14(8) of the RAE’s arbitration rules) and are enforceable in accordance with the relevant provisions of the Greek Code of Civil Procedure (see, inter alia, Articles 896 and 904).

157Fifthly, the decisions of the arbitration tribunals may be the subject of an appeal brought before an ordinary court, as can be seen by the applicant’s appeal against the arbitration award before the Efeteio Athinon (Court of Appeal, Athens) (see paragraph 12 above).

158It follows that the applicant has demonstrated to the requisite legal standard that the arbitration tribunals established and operating in accordance with Article 37 of Law No 4001/2011 form an integral part of the judicial system of the Greek State. Even in response to an express and specific question from the Court in that regard at the hearing, the Commission refrained from expressing an opinion on the question whether, because of those characteristics, the arbitration tribunal was akin to an ordinary State court, but merely reiterated that it was sufficient for it to rule that no advantage was granted to the intervener by applying the private operator principle to the applicant’s decision to refer the dispute to arbitration, as it did in the second contested decision.

159However, contrary to the argument put forward by the Commission at the hearing, having regard to its nature, the context in which its activity takes place, its objective and the rules to which it is subject, an arbitration tribunal, ruling under an arbitration procedure provided for by law and fixing an electricity tariff by means of a legally binding decision which may be challenged before the State courts, has the force of res judicata and is enforceable, like the arbitration award (see paragraphs 151 to 157 above), must be classified, in the same way as an ordinary Greek court, as a body exercising a power coming within the scope of public authority rights and powers.

–The Commission’s duty to verify whether the arbitration award conferred an advantage

160It is true that it follows from the case-law that the private operator principle cannot be applied to the arbitration award as such, given that the arbitration tribunal must be treated in the same way as an ordinary State court (see, to that effect, judgment of 11 December 2019, Mytilinaios Anonymos Etairia – Omilos Epicheiriseon v Commission, C‑332/18 P, EU:C:2019:1065, paragraphs 133 and 134) (see paragraphs 150 to 159 above). The fact remains that, by virtue of its powers and obligations recalled in paragraph 148 above, in order to be able to remove any doubt within the meaning of Article 4(3) and (4) of Regulation 2015/1589, the Commission was required to carry out a review as to whether a State measure which was not notified, such as the tariff in question fixed by that award, but which was challenged by a complainant, came within the definition of State aid, within the meaning of Article 107(1) TFEU, including the criterion relating to the conferral of an advantage which it claims to have applied in the present case.

161By virtue of its central and exclusive responsibility to ensure that, subject to the judicial review of the EU Courts, Article 107 TFEU is observed and Article 108 TFEU is implemented, the Commission is obliged to verify, inter alia, where necessary with the assistance of experts, whether a State measure entails an advantage which does not correspond to normal market conditions (see, to that effect, judgments of 16 September 2004, Valmont v Commission, T‑274/01, EU:T:2004:266, paragraph 72 and the case-law cited; of 9 December 2015, Greece and Ellinikos Chrysos v Commission, T‑233/11 and T‑262/11, EU:T:2015:948, paragraph 91; and of 16 March 2016, Frucona Košice v Commission, T‑103/14, EU:T:2016:152, paragraphs 164 to 179).

162According to settled case-law, measures which, whatever their form, are likely directly or indirectly to favour certain undertakings or which are to be regarded as constituting an economic advantage that the recipient undertaking would not have obtained under normal market conditions meet the conditions for the conferral of an economic advantage. Conversely, that is not the case if the recipient undertaking could, in circumstances which correspond to normal market conditions, have obtained the same advantage as that which has been made available to it through State resources (see, to that effect, judgment of 21 December 2016, Club Hotel Loutraki and Others v Commission, C‑131/15 P, EU:C:2016:989, paragraphs 70 and 71 and the case-law cited).

163Moreover, where the Commission is called upon to examine whether certain measures may be classified as State aid because the public authorities did not act in the same way as a private vendor, it must undertake a complex economic assessment, in the context of the review of which the EU judicature cannot substitute its own economic assessment for that of the Commission (see, to that effect, judgment of 24 October 2013, Land Burgenland and Others v Commission, C‑214/12 P, C‑215/12 P and C‑223/12 P, EU:C:2013:682, paragraphs 77 and 78 and the case-law cited). That assessment applies mutatis mutandis to the sale of electricity by an undertaking under State control, such as the applicant, which is capable of conferring an economic advantage on the purchaser that is not consistent with normal market conditions. Just as the sale of public land at a price lower than the market value may constitute State aid (see, to that effect, judgment of 16 July 2015, BVVG, C‑39/14, EU:C:2015:470, paragraph 27 and the case-law cited), the sale of electricity by such an undertaking at a price lower than the market value may confer on the purchaser, as a recipient, an advantage which, in essence, leads to a reduction of the State budget consisting in the State forgoing the difference between its market value and the lower price paid by that purchaser.

–The Commission’s duty to make complex economic and technical assessments to determine whether an advantage has been conferred

164In the light of those case-law principles and the arguments and claims put forward by the applicant in its complaints, in order to be able to remove any doubt within the meaning of Article 4(3) and (4) of Regulation 2015/1589, the Commission was not entitled, first, to waive its review as to whether the arbitration award involved the granting of an advantage (see paragraphs 160 to 163 above) and, secondly, to proceed with complex economic assessments, relating, in particular, to whether the tariff in question is consistent with normal market conditions. Moreover, it cannot avoid that obligation to carry out checks on the ground that, after a lengthy dispute, the applicant and the intervener had entered into an arbitration agreement containing criteria which were intended to predetermine the fixing of that tariff and, therefore, had engaged in arbitration proceedings the outcome of which was the ‘logical consequence’ of that agreement.

165Admittedly, as the Commission submits, the case-law has not laid down a general obligation for it to carry out, in all cases, a complex analysis of the hypothetical market price that the beneficiary of a given measure would have paid in the absence of that measure in order to establish the existence of an advantage for the purposes of Article 107(1) TFEU. Thus, where there is a manifest advantage arising from a mechanism for reimbursement, by means of a parafiscal levy, of the difference between the electricity tariff normally charged to undertakings and the preferential tariff granted, the Court of Justice has required proof of the existence of special circumstances making such an analysis necessary (see, to that effect, order of 21 January 2016, Alcoa Trasformazioni v Commission, C‑604/14 P, not published, EU:C:2016:54, paragraphs 38 to 40, confirming the judgment of 16 October 2014, Alcoa Trasformazioni v Commission, T‑177/10, EU:T:2014:897, paragraphs 82 to 84).

166It must be noted, however, that the facts at the origin of the present case are not comparable to those of the case which gave rise to the case-law cited in paragraph 165 above, in which the existence of an advantage was not in doubt. In the present case, the existence of a possible advantage linked to the tariff in question was not only highly contentious between the parties, but also difficult to determine, as demonstrated by the detailed and complex statement of reasons for majority and dissenting opinions set out in the arbitration award, in which the dissenting opinions challenged the soundness of the assessment by the majority of arbitrators precisely on the points at issue in the present dispute. The Commission could therefore neither conclude that there were no special circumstances within the meaning of that case-law which would have enabled it to dispense with such an assessment of the existence of an advantage, nor dispel any doubt in that regard on the basis of its assessment set out in paragraphs 43 to 48 of the second contested decision. In particular, it is not justified in arguing that the criteria of the arbitration agreement, as read in the light of the vague elements set out in Decisions No 692/2011 and No 798/2011 of the RAE, had predetermined, with sufficient precision, the outcome of the arbitration procedure, with the result that it had to be regarded as the ‘logical consequence’ of those criteria that was foreseeable by the applicant. On the contrary, the situation with which the Commission was confronted as a result of the applicant’s second complaint is comparable to the bringing of an action before an ordinary civil court for the purposes of interpreting and clarifying the provisions of a civil law contract the scope of which is disputed between the parties and in respect of which the Commission considers that it has a power of review, as is demonstrated by the facts of the parallel case to the present dispute which form the basis of the judgment of 11 December 2019, Mytilinaios Anonymos Etairia – Omilos Epicheiriseon v Commission (C‑332/18 P, EU:C:2019:1065).

167In the present case, the special circumstances which should have led the Commission to examine diligently, sufficiently and comprehensively (see the case-law cited in paragraphs 116 and 117 above) the possible grant of an advantage to the intervener by the arbitration award and to carry out complex economic and technical assessments in that respect, before removing any doubts or serious difficulties as to whether the concept of State aid within the meaning of Article 107(1) TFEU has been met, are as follows.

168In the first place, the arbitration agreement merely states that the intervener and the applicant ‘have agreed to have joint recourse to arbitration, as provided for under Article 37 of Law No 4001/2011 in order for – in accordance with the basic principles of pricing for high-voltage customers, as set out by the RAE in Decision No 692[/2011], but also taking into account … Decision No 798[/2011] and … Award No 8/2010 of the arbitration tribunal – the RAE to update and adapt the pricing conditions contained in the draft [electricity supply] contract drawn up on 5 October 2010 with a view to implementing the [framework] agreement, and, in the framework of the [said] decisions …, to draw up the contractual conditions for supply between the parties which are applicable from 6 June 2011, so that those conditions, first, correspond to [the intervener’s] consumption profile and, secondly, cover at least the costs borne by [the applicant].’ Contrary to the Commission’s view, it must be stated that, in particular, the criteria pertaining to ‘[the intervener’s] consumption profile’ and ‘the costs borne by [the applicant]’ do not allow an appropriate amount from the electricity tariff sought to be easily deduced, which is confirmed by the detailed and complex analysis which the arbitration tribunal was required to carry out in that regard (see paragraphs 171 to 184 below).

169In the second place, with regard to the pricing method, Decision No 692/2011 of the RAE merely states, inter alia, that ‘prices must reflect actual electricity supply costs … and cover the cost of production as it appears on the wholesale market …, the cost of marketing and customer management activities … and a reasonable profit’. With regard to ‘large customers’, including ‘medium and high-voltage customers’, such as the intervener, there is the option ‘to offer tailored tariffs, which are adapted to their characteristics and to the services offered and agreed between the supplier and the customer’. Billing for the supply of electricity must be such as to, inter alia, ‘reflect as closely as possible the short-term and long-term costs generated by the shape of the load curve and the consumption volumes of the categories of consumers in the electricity production system’. In addition, ‘the prices offered to each category of customers may be different’ depending on, inter alia, the load curve and the load factor. Furthermore, ‘the differentiation in tariffs according to the time, day of the week or season presupposes the existence of specific measuring arrangements’ and ‘the zones and corresponding rates set will have to take account of the load curve for the category of customers concerned’. Finally, ‘as far as very high consumption is concerned, account must also be taken of the positive or negative outcome that the activities of those very large consumers may have as their consumption alone may affect the operation and therefore the total costs of the system’. It follows that the pricing criteria set out in Decision No 692/2011 of the RAE provide only for a methodological framework for determining the relevant costs and fixing the electricity tariff, without, however, being such as to determine to the requisite standard its precise amount.

170In the third place, with regard to the applicable criteria in order to resolve the dispute between the applicant and the intervener, Decision No 798/2011 of the RAE also does not provide sufficiently clear and precise indications to that end. That decision states, first, that ‘the purpose of the option to conduct negotiations between [high-voltage] customers and, in particular, a customer with [the intervener’s] electricity consumption profile, which represents approximately 5% of the total consumption of the interconnected system, and the main supplier, namely [the applicant], is to explore and quantify the possibilities of optimising the contract by internalising any advantages that may arise both in the functioning of the daily programming of resources and in the planning of the long-term development of the system, advantages that may arise from significant use and, in particular, from the volume of consumption of [the intervener], whose consumption alone justifies the construction and cost-effective operation of a 300 MW electricity generation plant, taking into account also … the combination of the large size and high load factor of this consumer’ and that ‘it goes without saying that the existence or otherwise of a consumer of the [intervener’s] size has a decisive influence both on [the applicant’s] commercial plan and on the electricity market as a whole’. Secondly, that decision states, inter alia, that ‘the number of low-load hours may … constitute information relevant to billing, provided that the parties to the negotiation agree on the actual conditions of consumption and on the fuel mix to generate the electricity, on the one hand, and the way in which that contractual clause may be amended, on the other’. Thirdly, it states that, ‘in the calculation of the low-rate hours, as set out in the “basic principles for pricing”, account should also be taken of[, first], the costs spared as a result of [the intervener’s] high consumption, in particular the evening hours when, if that consumption did not exist, a base unit would have to be powered down, and[, secondly,] the loss of income which could result from the long-term reduction in consumption, on account of the loss of a customer who represents 5% of the total consumption of the interconnected system’. It is concluded that ‘it would be appropriate to update the wording of the draft [electricity supply] contract offered on the basis of the “basic principles for pricing of electricity” (Decision No 692/2011 of the RAE), on the one hand, and the specific comments made in this document, relating in particular to consumption which is significant and stable over time, such as [the intervener’s], on the other’.

171In the fourth place, as regards the content of the arbitration award, it must be borne in mind that that award initially takes a view on the intervener’s consumption profile (see the majority opinion set out in paragraphs 77 to 99 of that award) as the largest energy consumer, with a share of approximately 40% of the total consumption of high-voltage customers in Greece, which was dependent on the applicant as the only supplier in Greece with a market share exceeding 98% and owning approximately 70% of the power stations, including 100% of lignite-fired power stations and large hydroelectric plants.

172Secondly, with regard to the determination of the applicant’s costs and the tariff in question, it is clear from the majority opinion, in essence, that the regulated A-150 tariff has become inapplicable following the liberalisation of the Greek energy market (paragraphs 100 to 112 of the arbitration award) and is incompatible with the intervener’s consumption profile and, therefore, with the arbitration agreement (paragraphs 113 to 118 of that award), and that, furthermore, a tariff based on the marginal price of the system does not reflect the applicant’s costs (paragraphs 119 to 140 of that award).

173In that regard, in view of the possibility of adjusting the supply tariff, inter alia, on the basis of the customer’s consumption profile, the structure of the Greek energy market, the applicant’s dominant position and the applicant’s balance sheet for 2011, the arbitration tribunal considers that account should be taken not only of its supply costs but also of its income generated as a producer (paragraphs 127 and 128 of the arbitration award). It states that those supply costs and that income are set out in that balance sheet as separate expenditure (costs) from the activities of supplying energy and, therefore, separate income from those activities. However, in its view, what is referred to in the consolidated balance sheet as being the applicant’s actual cost is the difference between those two financial flows, since that internal accounting transfer of the financial flows between the applicant’s supply and production entries is based on what has been referred to as the ‘bilateral financial agreement’ (paragraphs 123 and 124 of that award). In that regard, it recalls that Decision No 692/2011 of the RAE refers to the actual costs of energy supply and links them, inter alia, to the costs of energy production, like the ‘pool’ market and its individual mechanisms (paragraph 125 of that award).

174According to the arbitration tribunal, the marginal price of the system does not represent the applicant’s actual costs. As a vertically integrated undertaking, its actual costs are to be established on an annual rather than an hourly basis, taking into account the variable and fixed total costs of all of the power plants available to it, plus the costs of purchases made by it from third parties through the ‘DAS system’, plus the costs incurred by energy suppliers outside that system, in accordance with the applicable rules (paragraph 129 of the arbitration award). In that regard, it rejects the applicant’s proposal to determine the tariff on the basis of the marginal price of the system based on a report drawn up by an auditing firm (paragraphs 131 to 140 of that award) on the ground, inter alia, that, in accordance with Decision No 692/2011 of the RAE, the price of the energy supply must be determined using a method which ‘reflects the load curve and total consumption of each category of consumers and takes into account the load curve for each consumer or category of consumers … rather than the load curve for the complete system’. It concludes from this that the tariff proposed by the applicant cannot be applied to a consumer like the intervener (paragraphs 139 and 140 of that award).

175With regard to the tariff proposed by the intervener, based on the variable and fixed costs of all the applicant’s lignite-fired power stations, the arbitration tribunal points out, first, that, in accordance with Decision No 692/2011 of the RAE, such a tariff must reflect the sum of the production costs, the costs of managing the supply and a reasonable profit margin (paragraphs 141 to 145 of the arbitration award) and, secondly, that it corresponds to the ‘C tariff’ described by the expert Mr K., which reflects the minimum long-term cost for each consumer and which, according to that expert, is based on the total costs of a base load power station, that is to say lignite or hard coal, unlike the tariff proposed by the applicant, which is based on the time-weighted average of the marginal price of the system (paragraphs 148 and 149 of that award). In its view, that opinion has been confirmed by other experts whose testimonies are summarised in paragraphs 150 to 154 of that award. It concludes that it is an entirely appropriate practice in the energy market for a consumer such as the intervener to be charged a tariff based on the total energy costs of base load lignite power stations and that such a tariff complies with the criteria laid down in Decision No 692/2011 of the RAE (paragraphs 155 and 156 of the arbitration award).

176In that regard, the arbitration tribunal rejects the applicant’s reasoning seeking to challenge that assessment since the tariff it proposes is incompatible with Decisions No 692/2011 and No 798/2011 of the RAE in so far as it implies that the total costs are allocated equally among all consumers with the result that each consumer is charged the same price for each hour of the day. That ‘horizontal distribution tariff’ would result in considerably higher prices for households and other consumers who do not have a typical consumption profile, thus those at peak load (paragraphs 156 to 163 and 169 of the arbitration award). The same applies to the applicant’s argument that the costs of base load lignite power stations do not reflect the costs of supply, since the dispute brought before it does not concern the applicant’s costs, but the application of a tariff covering those costs and taking account of the intervener’s consumption profile, in accordance with Decision No 692/2011 and taking account of Decisions No 798/2011 and No 8/2010 of the RAE. According to the arbitration tribunal, if the pricing proposed by the intervener was applied separately to every consumer or category of consumers, it would lead to the recovery of 100% of the applicant’s costs per year, which satisfies the fundamental pricing principles and the conditions of the arbitration agreement (paragraph 165 of that award). Moreover, it disputes that the pricing proposed by the intervener results in cross-subsidisation between different categories of consumers or may distort competition and rejects the applicant’s other arguments seeking to challenge that assessment (paragraphs 166 to 183 of that award).

177Finally, with regard to the reasonableness of the conditions of supply set out in the arbitration agreement, the arbitration tribunal states, in paragraphs 184 to 207 of the arbitration award, essentially the following:– the application to the intervener of the tariff based on the marginal price of the system, as proposed by the applicant, is incompatible with the arbitration agreement on the ground that that tariff does not reflect the applicant’s actual costs (paragraphs 185 and 186);– the application of the A-150 tariff to the intervener is incompatible with the arbitration agreement; (paragraph 187);– of all the proposed pricing methods, the only one compatible with the arbitration agreement is one which imposes a single-zone flat-rate tariff spread over all the hours of the year and based on the costs of the lignite-fired power stations operated by the applicant (paragraph 188);– the draft agreement must be updated, amended and configured in accordance with the foregoing; to that end, the price resulting from that tariff, which corresponds to the characteristics of the intervener’s consumption and covers the applicant’s costs during the period in question at the very least, must be determined (paragraph 189);– the applicant failed to provide sufficient information establishing the actual costs of its lignite-fired power stations during the period in question (paragraph 191);– the information provided regarding the production costs of hard coal and lignite-fired power stations which could have been or will be built in the future cannot be taken into account, since they do not relate to the costs associated with existing power stations during the period in question (paragraph 193);– in accordance with Mr B.’s sworn statement, which provides detailed, complete and reliable information on the costs of the applicant’s lignite-fired power stations during the period in question, the cost of lignite fuel in 2009 was 24.5 EUR/MWh, whereas the cost of ‘energy’, that is to say, the fixed cost plus the variable cost unrelated to the cost of fuel, plus depreciation and the financial cost of production, was 12.2 EUR/MWh, and therefore the total production cost of lignite-fired power stations was 36.46 EUR/MWh, adjusted to 37.34 EUR/MWh when taking into account the reasonable cost of extraction and marketing (paragraph 195);– as regards the applicant’s fixed costs per unit which must be charged to the intervener, the calculation set out in paragraph 200 of the arbitration award results in an amount of 12.1 EUR/MWh (paragraph 201);– the tariff corresponding to the characteristics of the intervener’s consumption and covering the applicant’s costs for the period in question must be fixed at the (net) amount of 36.6 EUR/MWh (24.5 + 12.1) (paragraph 202);– in view of the fact, in particular, that, first, under the January 2012 tariff, the intervener pays the applicant the amount of 4.06 EUR/MWh in respect of various charges, services and costs and that, secondly, the intervener’s consumption remains virtually stable throughout the year and has not changed during the period in question, that amount is a reasonable estimate for that period and fixes the total tariff at 40.66 EUR/MWh (36.6 + 4.06) (paragraph 203);– in relation to the 4710 hours, the total price per unit which the applicant had agreed to charge the intervener in the framework agreement was 40.70 EUR/MWh which included all the charges set out in paragraph 1.2 of that framework agreement, with the result that it is established that that price covers both the applicant’s production costs and those charges (paragraphs 204 and 205);– the tariff which the applicant had agreed to charge the intervener for the supply of energy under the framework agreement in respect of 4710 hours of the year, namely 40.7 EUR/MWh, if applied to the total hours of the year, covers the applicant’s total costs, namely 36.6 EUR/MWh, which is consistent with the characteristics of the intervener’s consumption, in accordance with the arbitration agreement, if the applicable charges are added (40.66 EUR/MWh) (paragraph 206).

178The assessment of the majority opinion in the arbitration award set out in paragraphs 171 to 177 above is challenged by the dissenting opinion in that award in paragraphs 217 to 262 thereof.

179As regards the applicant’s costs, the dissenting opinion in the arbitration award maintains, in essence, that it cannot be ignored that the applicant operates currently, as it did in the period in question, as a vertically integrated undertaking engaged at the same time in the production and supply of energy. The applicant’s actual costs, in that capacity, on an annual and not an hourly basis, consist of the total variable and fixed costs of all of its power plants, during the period in question, plus the costs of purchases made by it from third parties through the ‘DAS system’, plus the costs incurred by energy suppliers outside that system, imposed by the applicable rules, including the energy supply certificates (PDC), the variable cost recovery mechanism, the cost of purchasing CO₂ emission rights, other charges imposed by the State, such as system and network usage charges, the special charge on gaseous pollutant emissions, and any taxes applicable from time to time under Greek legislation governing the supply of electricity. Since the level of relevant costs from in-house production and the supply by third parties varies by day and by hour, it is therefore reasonable to adopt a 70/30 ratio in that regard. It would be contrary to the criteria of the arbitration agreement relating to the applicant’s actual costs, as a vertically integrated undertaking, to isolate or focus on one of those two components without taking account of the other. For the same reasons, those costs cannot be limited either to the costs of energy production or to a single category of power stations operated by the applicant (paragraphs 217 to 222 of that award).

180The dissenting opinion in the arbitration award sets out the reasons why it considers that the majority opinion is based on an incorrect pricing method by taking into account the applicant’s actual total costs (paragraphs 227 to 262 of that award).

181According to the dissenting opinion in the arbitration award, first, in essence, the majority opinion acknowledges that the marginal price of the system as such does not reflect the applicant’s actual costs and is not used solely for the purpose of determining those costs, but that time-weighted price is also a means of pricing the volume of energy supplied to the applicant by third parties. The method proposed by the applicant would allocate the cost of supply to consumers which is based exactly on the characteristics of the system, on the basis of the amount of energy consumed by each consumer during each hour. According to that method, large consumers would be charged a lower price than peak consumers since the cost of the energy supply would be spread over a greater number of hours. That method is therefore fully compatible with the principles established in Decision No 692/2011 of the RAE, the criteria of the arbitration agreement and the intentions of the contracting parties. It is a cost-based method which, first, takes account of the profile of each consumer, in particular their consumption curve and load factor, secondly, reflects more accurately the actual costs of supplying energy (production cost, exchange cost, reasonable profit), thirdly, does not lead to prices which prevent new competitors from entering the market, which would be the case where the tariff is based on the cheapest energy source, and, fourthly, takes account of the fact that the intervener, together with other consumers, has a demand for energy during each hour of the day (paragraphs 231 and 232 of the arbitration award).

182Moreover, the dissenting opinion in the arbitration award recalls, in essence, the three technical reports drawn up by an auditing firm, according to which the time-weighted average cost incurred by the applicant in relation to the production of energy and the supply of electricity by third parties was 72.42 EUR/MWh in 2011 and 78.53 EUR/MWh in 2012. Those prices should be subject to volume discounts in accordance with the requirements of competition law (paragraphs 233 and 234 of that award).

183Furthermore, the dissenting opinion in the arbitration award criticises the reasoning relating to the pricing method, inter alia, as being incompatible with the requirements of the arbitration agreement and Decision No 692/2011 of the RAE (paragraphs 235 to 249 of that award). In particular, the global reference to the variable and fixed costs of the least expensive generation capacity creates a distorted picture of the applicant’s costs since the combination of fixed and variable costs of power plants varies according to the number of hours of operation. Thus, the reference to lignite-based energy creates the erroneous impression that the cost will be reduced during peak hours since it takes account only of the variable costs of a particular category of power stations, and not of the involvement of power stations with a higher total cost of production per unit during the same period (paragraph 245 of that award). Moreover, it states that the pricing method endorsed by the majority opinion does not provide appropriate incentives for a more rational use of energy since it unreasonably limits the ability of consumers to benefit from the lower variable costs of lignite-fired power stations (paragraph 246 of the arbitration award). Furthermore, that method is said to create a high risk of barriers to market entry to the detriment of new competitors while at the same increasing the possibility of illegal dumping. Nor is there any justification for establishing a link between the tariff to which the intervener is entitled and the costs of lignite-fired power stations, since the latter feed all of the energy produced in the ‘pool’, which makes it impossible to verify the existence of such a link. Thus, consumers who contribute to the creation of the total demand will be supplied with energy by a mixture of low, intermediate and high-cost power stations which vary according to the time of consumption. The intervener is not an exception in that regard, but contributes to system demand during both peak and off-peak hours, and therefore the tariff should reflect the average operating cost of all power stations (paragraphs 247 and 248 of the award in question).

184Finally, the dissenting opinion in the arbitration award challenges the method for determining the unit price which consists of linking the base load to the base load unit (paragraphs 250 to 262 of that award). For reasons of logic and systemic coherence, such a method should be based on the total fixed and variable costs of the lignite-fired power station and not on a mixture of cost elements from several methodological approaches. Moreover, such a calculation would essentially concern the costs of an existing plant of the supplier in question and should not take account of hypothetical models (paragraph 251 of that award). With regard to the variable costs of lignite-fired power stations, the dissenting opinion contests the validity of Mr B.’s conclusions (paragraphs 252 and 253 of that award). In essence, it considers it unproven that the tariff of 40.7 EUR/MWh provided for in the framework agreement covers the applicant’s production costs and expenses (paragraph 254 of the award in question) and takes the view that the tariff cannot in any event be lower than 46.08 EUR/MWh taking into account the average cost of lignite at 33.98 EUR/MWh, etc. and the energy costs of 12.1 EUR/MWh (paragraphs 262 and 274 of that award). Lastly, it casts doubt on the conclusions of the majority opinion in the light of the rules on State aid (paragraphs 263 to 268 of the award in question).

185It follows from all of the foregoing considerations that, without giving rise to any doubts or serious difficulties, the Commission was not entitled to refuse to verify, on the basis of a complex analysis of normal market conditions, whether the tariff in question, as fixed by the majority opinion in the arbitration award, was capable of conferring an advantage on the intervener and, therefore, constituted State aid.

186First, the detailed account of the controversial reasons underlying the majority and dissenting opinions in the arbitration award demonstrates that the establishment of the appropriate pricing method and, in particular, the applicant’s ‘actual’ costs involves complex economic and technical assessments relating to both the structure and functioning of the Greek energy market and the respective economic situations of the intervener and the applicant, including their transactional relationships, which are relevant for determining whether a tariff for the supply of energy corresponds to a ‘market price’. As is clear from the considerations set out in paragraphs 164 to 185 above, by confining itself to applying the private operator principle to the question of whether such an operator would have referred the dispute to arbitration, like the applicant did, the Commission delegated those complex assessments to the Greek authorities while at the same time disregarding its own duty of review referred to in paragraphs 143 to 148 above, or even committing an error of law and of assessment in that regard.

187Secondly, having regard to the detailed and contradictory information set out by the majority and dissenting opinions in the arbitration award, it must be observed that, in the light of the information submitted by the applicant during the administrative procedure, including the three technical reports provided by an auditing firm, the Commission should have carried out its own analysis of the question of whether, in particular, the method for determining the applicant’s costs, as applied by the arbitration tribunal, was both appropriate and sufficiently plausible to establish that the tariff in question was consistent with normal market conditions, without giving rise to serious difficulties or doubts, within the meaning of Article 4(3) and (4) of Regulation 2015/1589, as to whether it constituted State aid, which should have led it to decide to initiate the formal investigation procedure under Article 108(2) TFEU.

188In that regard, the Commission should in particular have had doubts in the light of the following controversial factors:– the characterisation of the applicant’s costs by reason of its status as a vertically integrated undertaking, the consolidated balance sheet of which is based on an internal accounting transfer of financial flows between the applicant’s supply and production entries (on the basis of the so-called ‘bilateral financial agreement’) (see paragraph 173 above);– the alleged need to establish the applicant’s actual costs on an annual rather than an hourly basis by taking account, in particular, of the variable and fixed total costs of all of the power plants available to it (see paragraph 174 above);– the relevance of the choice between the tariff proposed by ‘DEI/PwC’, based on the marginal price of the system and on the time-weighted average, leading to a ‘horizontal distribution tariff’, on the one hand, and the tariff proposed by the intervener which is based on the fixed and variable costs of the applicant’s lignite-fired power stations, thus on the minimum long-term cost for each consumer, on the other (see paragraph 174 above);– the link between those proposed tariffs and the need to cover the applicant’s actual (variable and fixed) costs and its impact on the tariffs to be charged to the different consumption profiles, either base load, like the intervener’s, or peak load or high (see paragraph 174 above);– the potential impact of the choice of pricing method on competition in the Greek energy market (see paragraph 176 above);– the sufficiency of the information provided by the applicant in order to establish its actual costs, in particular those relating to the operation of its lignite-fired power stations (see paragraph 177 above).

189It must be noted that, in the second contested decision, the Commission did not, contrary to what it submits, satisfy the monitoring requirements incumbent upon it in the light of the objective concept of doubts or serious difficulties by taking into account, solely in its view as an ‘illustration’, the regulatory framework for the electricity market in Greece (paragraphs 18, 20, 21, 29, 33, 37, 40 and 41 and footnotes 5, 6 and 13 to 18), the intervener’s consumption profile (paragraph 31 and footnote 3), the characteristics of the applicant as an electricity producer and supplier (paragraph 30 and footnote 7), and the general circumstances of the dispute between the applicant and the intervener (Sections 2.1 and 2.2 and paragraphs 34 to 38 and 42).

190Moreover, in view of the fact that the Commission failed to examine those complex economic and technical elements, where necessary with the aid of internal or external experts, and to give reasons for the second contested decision in that regard, it is neither necessary nor legally possible for the Court to substitute its assessment for that of the Commission. In that regard, it is not for the EU Courts to substitute their own economic assessment for that of the Commission, or to fill a possible gap in the reasoning for the contested decision by means of grounds which did not form part of that decision, as this would exceed the limits of their review of legality under Article 263 TFEU (see, to that effect, judgments of 24 January 2013, Frucona Košice v Commission, C‑73/11 P, EU:C:2013:32, paragraphs 75, 88 and 89; of 24 October 2013, Land Burgenland and Others v Commission, C‑214/12 P, C‑215/12 P and C‑223/12 P, EU:C:2013:682, paragraphs 77 and 78 and the case-law cited, and of 11 December 2019, Mytilinaios Anonymos Etairia – Omilos Epicheiriseon v Commission, C‑332/18 P, EU:C:2019:1065, paragraphs 128 to 131).

191It follows that, in the present case, the Court cannot assess the merits of the applicant’s various complaints and arguments with regard to whether the arbitration tribunal’s assessment underlying the determination of the tariff in question might be wrong in law or in fact, or whether or not the present case is comparable to the situation which gave rise to the Alcoa decision. The factors set out above are sufficient to conclude that, in the absence of further examination of the information relevant to the application of the criterion relating to the conferral of an advantage, in particular whether the tariff in question corresponded to normal market conditions, the Commission ought to have encountered serious difficulties or had doubts within the meaning of Article 4(3) and (4) of Regulation 2015/1589 requiring it to initiate the formal investigation procedure.

(c)Conclusions with regard to Case T‑740/17

192Accordingly, the third and fourth pleas and the first and second parts of the fifth plea must be upheld, without there being any need to rule on the other parts of that plea.

193Consequently, the action in Case T‑740/17 must be upheld and the second contested decision annulled, without there being any need to rule on the other pleas in law.

194Since the second contested decision is thus declared void within the meaning of the first paragraph of Article 264 TFEU, it shall be removed retroactively from the legal order and deemed never to have existed (see, to that effect, judgment of 28 March 2019, River Kwai International Food Industry v AETMD, C‑144/18 P, not published, EU:C:2019:266, paragraphs 45 to 57). It follows that that decision was not capable of repealing and replacing either the first contested decision or the contested letter.

195Therefore, as the Commission acknowledged at the hearing in that case, Cases T‑639/14 RENV and T‑352/15 have not become devoid of purpose and it is necessary to rule on the actions in those cases.

C. Case T‑352/15

196With regard to the action in Case T‑352/15, it is sufficient to note that, first, in the light of what is set out in paragraphs 194 and 195 above, it retains its purpose, and therefore the Commission’s application for a declaration that there is no need to adjudicate must be rejected.

197Secondly, for the reasons set out in paragraphs 70 to 103, which apply mutatis mutandis to the first contested decision, the content of which is almost identical to that of the second contested decision, the action must be declared admissible.

198The pleas for annulment relied on in support of that action are preceded by an introductory section stating its purpose which is to invoke the existence of ‘[serious] doubts’ or ‘serious difficulties’ within the meaning of the case-law. Similarly, in the context of the first, third, fourth, fifth and sixth pleas, explicit reference is made to the concepts of ‘doubts’ or ‘serious difficulties’ (paragraphs 61, 62, 87, 100, 114, 119, 134, 158, 176 and 196 of the application). With regard to the second plea, alleging infringement of the obligation to state reasons and to examine the case diligently and comprehensively, which is essentially formal and procedural in nature, the considerations set out in paragraph 100 above apply mutatis mutandis.

199Thirdly, given that the content of the contested decisions is almost identical, for the reasons set out in paragraphs 138 to 192 above, the second and third pleas and the first and second parts of the fourth plea, which correspond to the third and fourth pleas and the first and second parts of the fifth plea in Case T‑740/17, must be upheld.

200It follows that the action in Case T‑352/15 must also be upheld and the first contested decision must be annulled, without there being any need to rule on the other parts of the fourth plea and the other pleas put forward by the applicant.

201In accordance with what has been stated in paragraph 194 above, since the first contested decision is null and void, it was not capable of repealing or replacing the contested letter, with the result that Case T‑639/14 RENV could not become devoid of purpose on that ground.

202Therefore, for that reason also, it is necessary to rule on Case T‑639/14 RENV.

D. Case T‑639/14 RENV

1. The application for a declaration that there is no need to adjudicate and admissibility

203As a preliminary point, the Commission’s application for a declaration that there is no need to adjudicate must be rejected for the reasons set out in paragraphs 194 and 201 above.

204As far as the admissibility of the action is concerned, it is sufficient to recall the reasons set out in paragraphs 70 to 103 above which apply mutatis mutandis to the contested letter and from which it is also apparent that that letter constitutes a challengeable act.

205In that regard, the Court of Justice held that, by the adoption of the contested letter, the Commission had closed the file, deciding to close the preliminary examination procedure triggered by the applicant’s complaint, had held that in the inquiry opened it was not possible to conclude that there had been aid within the meaning of Article 107 TFEU and, accordingly, had refused to open the formal investigation procedure provided for under Article 108(2) TFEU. In its view, the Commission therefore adopted a definitive position on the applicant’s request for a finding of infringement of Articles 107 TFEU and 108 TFEU. It stated that, as that letter had prevented the applicant from submitting its observations in a formal investigation procedure, it had produced binding legal effects capable of affecting the applicant’s interests. It concluded that that decision constituted an act open to challenge for the purposes of Article 263 TFEU (see, to that effect, judgment of 31 May 2017, DEI v Commission, C‑228/16 P, EU:C:2017:409, paragraphs 30 and 31 and the case-law cited).

206Moreover, the pleas in law raised in support of the action are preceded by an introductory section stating its purpose which is to invoke the existence of ‘[serious] doubts’ or ‘serious difficulties’ within the meaning of the case-law (see paragraphs 51 to 53 of the application). Similarly, the concepts of ‘doubts’ or ‘serious difficulties’ are expressly referred to in connection with the second and third pleas in law relating to the criteria of whether the measure could be attributed to the State (paragraphs 90 and 128 of the application) and whether the measure confers an advantage (paragraphs 145 and 152 of the application). With regard to the first and fourth pleas in law, it is sufficient to note that they are formal and procedural in nature and relate precisely to the question whether the Commission investigated and gave reasons for all of the relevant and necessary factors in order to overcome the doubts and difficulties which arose in the preliminary examination stage (see, to that effect, judgments of 10 July 2012, Smurfit Kappa Group v Commission, T‑304/08, EU:T:2012:351, paragraph 81; of 20 June 2019, a&o hostel and hotel Berlin v Commission, T‑578/17, not published, EU:T:2019:437, paragraph 59 and the case-law cited, and of 12 September 2019, Achemos Grupė and Achema v Commission, T‑417/16, not published, EU:T:2019:597, paragraph 52 and the case-law cited).

207Consequently, the action must be declared admissible in respect of all the pleas in law raised in support of it.

2. Substance

(a)The pleas for annulment

208In support of the present action, the applicant raises four pleas for annulment.

209By the first plea, the applicant submits that the contested letter is vitiated by an infringement of an essential procedural requirement, on the ground that the Commission did not comply with the procedural requirements for adopting a decision to take no further action on a complaint.

210By the second plea, the applicant submits that the Commission committed a manifest error of assessment ‘as regards the law and the facts’ in respect of the interpretation and application of Articles 107 and 108 TFEU by taking the view that the measure at issue could not be imputed to the Greek State and, therefore, did not constitute State aid.

211By the third plea, the applicant considers that the Commission committed a manifest error of assessment ‘as regards the law and the facts’ in respect of the interpretation and application of Articles 107 and 108 TFEU by taking the view that the measure at issue did not have the effect of granting an advantage to the intervener.

212By the fourth plea, the applicant submits that the Commission infringed its obligation to state reasons, its obligation to examine all the relevant matters of fact and law and the principle of ‘sound administration’.

(b)The first plea, alleging infringement of an essential procedural requirement

213The applicant submits, in essence, that the contested letter is vitiated by a formal or procedural defect since, instead of that letter, signed by a Head of Unit of the ‘Competition’ DG and addressed to the applicant, the Commission was required to adopt a formal decision under Article 24(2) of Regulation 2015/1589 and to address it to the Hellenic Republic.

214The Commission, supported by the intervener, contends that the first contested decision was adopted by the College of Commissioners, under Article 4 of Regulation 2015/1589, and therefore the contested letter, as supplemented by that decision, is not vitiated by an infringement of an essential procedural requirement. It states that the applicant continues to confuse its main argument, that that decision validly replaced that letter and that it must therefore be declared that there is no need to adjudicate, with its argument in the alternative that that decision remedied the defects in that letter. The ‘elements added’ by that decision are precisely those intended for that purpose.

215In that regard, it is sufficient to note that, first, the Commission acknowledged, at the latest by the adoption of the second contested decision, that the present plea in law was well founded. The contested letter amounts to a definitive statement of the position of the Commission’s services on the applicant’s complaints by deciding to take no further action in their regard. It follows from settled case-law that such a letter contains a challengeable decision, adopted at the end of the preliminary examination stage, under Article 4(2) or (3) of Regulation 2015/1589, which is implicitly addressed to the Member State concerned and which must therefore be taken by the Commission as a collegiate body (see, to that effect, judgments of 17 July 2008, Athinaïki Techniki v Commission, C‑521/06 P, EU:C:2008:422, paragraphs 37 to 40; of 16 December 2010, Athinaïki Techniki v Commission, C‑362/09 P, EU:C:2010:783, paragraph 63; and of 31 May 2017, DEI v Commission, C‑228/16 P, EU:C:2017:409, paragraph 29).

216Secondly, the Commission acknowledges that the contested letter was not adopted in accordance with the relevant procedural rules for that purpose (see paragraph 222 below), which is precisely the justification on which it relies in paragraphs 8 and 51 of the second contested decision and in its defence in Case T‑740/17 for the purposes of the withdrawal and replacement of that letter by that decision, in accordance with the requirements laid down by the Court of Justice in its judgment of 31 May 2017, DEI v Commission (C‑228/16 P, EU:C:2017:409, paragraphs 32, 40 and 41).

217Accordingly, the present plea in law must be upheld.

(c)The second plea, alleging a manifest error of assessment as regards the law and the facts in respect of the interpretation and application of Articles 107 and 108 TFEU in relation to the criterion of whether the measure could be attributed to the State

218The applicant submits, in essence, that the Commission committed a manifest error of assessment ‘as regards the law and the facts’ in the interpretation of Articles 107 and 108 TFEU by claiming that the arbitration award could not constitute an aid measure attributable to the Greek State. In its view, recourse to arbitration is an alternative mechanism to the settlement of disputes by the ordinary courts while essentially producing the same legal effects, in particular as regards the binding and enforceable nature of the decision ultimately given. It considers that, by its nature and purpose, that award is an act of public authority that can be attributed to the Greek State, which obliges it, in a legally binding and enforceable manner, to release State resources. It concludes from this that the tariff in question is attributable to the Greek State and therefore the Commission, at the very least, ought to have expressed ‘serious doubts’ and, therefore, initiated the formal investigation procedure in order to enable it, inter alia, to submit its observations.

219The Commission, supported by the intervener, points out that the second and third pleas in law relate to the conditions of the measure being attributable to the State and an advantage being conferred. In the defence, it merely claims that, given that the conditions for a finding of State aid are cumulative, it is sufficient that the failure to satisfy one of those two conditions is established in order to conclude that no State aid is involved. It then expresses its view solely on the question whether the existence of an advantage can be ruled out on the ground that the applicant acted as a prudent private investor.

220In the rejoinder, the Commission adds that the second and third pleas in law are ineffective since neither of them, on their own, are capable of leading to the annulment of the contested letter. Since that letter is based on the fact that the combined conditions of the measure being attributable to the State and the conferral of an advantage are not met entailing the conclusion that no State aid was granted, to that end, the applicant should have raised a single plea alleging infringement of Article 107(1) TFEU on account of the incorrect assessment that the measure was not attributable to the State and did not confer an advantage. According to the Commission, the second plea in law, on its own, is not capable of resulting in that annulment ‘since the absence of an advantage is not argued in respect of that plea in law and is sufficient to conclude that there was no State aid’. The same applies to the third plea in law ‘since the fact that the measure was not attributable to the State is not argued in respect of that plea in law and is sufficient to conclude that there was no State aid’.

221The Commission states, in essence, that the fact that the measure was not attributable to the State is not the ‘essential part’ of the reasoning in the contested letter. Both that aspect and the aspect concerning the absence of an advantage were addressed only briefly in that letter and the conclusion that there was no State aid was based on those two equally important elements. By contrast, the statement of reasons for the first contested decision focused on the lack of an advantage, which was sufficient to conclude that there was no State aid. The contested letter therefore set out only a ‘very preliminary’ conclusion in that regard, which was not structured as clearly as in a formal decision of the Commission.

222The Commission disputes that it intended to avoid a judicial review of the contested letter. It states that that letter is the purely preliminary expression of the opinion of its services. It points out that it was only by mistake, and therefore in an unlawful manner, that, in that letter, the member of staff who signed it definitively set out the opinion of those services. It maintains that that infringement of an essential procedural requirement was, however, regularised by the adoption of the second contested decision which set out its final reply in the prescribed manner. The applicant cannot establish a legitimate interest in the examination of a reason in the letter in question, in particular that relating to whether the measure was attributable to the State, since such an interest presupposes that the action is likely, if successful, to procure an advantage.

223It must be recalled that, first, in the contested letter, in respect of the question as to whether the arbitration award is attributable to the Greek State, it is stated, inter alia, that the applicant has not demonstrated that ‘the arbitration tribunal [was] a body exercising State authority, especially since both [the applicant and the intervener] resorted voluntarily to the arbitration, without any legal obligation to that end’. Moreover, the opinion is taken in that letter that, in view of the fact that the arbitration tribunal had a mandate to set a tariff in accordance with the general principles governing the arbitration procedure, in addition to decisions and guidelines previously adopted by the RAE on the subject, ‘the [Greek] State [did] not seem to have had the possibility to dictate [that award]’. The Commission therefore reiterated its position ‘as expressed in the letter of 6 May 2014 as regards the fact that [that award] is not attributable to the [Greek] State’. Secondly, it rejected the applicant’s allegations that the tariff in question was lower than its costs, inter alia on the ground that that award explicitly acknowledged that that tariff covered the costs of the applicant plus a reasonable profit, while at the same time taking into account the consumer profile of the intervener. It therefore reiterated its position ‘expressed in the letter of 6 May 2014 as regards the absence of a selective advantage in the measure in question’ (see also paragraph 16 above).

224It follows that the Commission indeed took the view in the contested letter, first, that the arbitration award was not attributable to the Greek State and, secondly, that the fixing of the tariff in question in that award did not involve the grant of an advantage to the intervener. Therefore, its conclusion that there was no State aid was based on those two elements together.

225However, in the contested decisions, the Commission does not reiterate the considerations set out in the contested letter concerning the fact that the arbitration award is not attributable to the Greek State. On the contrary, it no longer makes any reference to that assessment, nor does it take a decision on whether the criterion of the measure being attributable to the Greek State is met, notwithstanding the fact that, first, the summary of the complaints set out in paragraph 11 of those decisions takes account of the applicant’s argument that that award was attributable to the Greek State and that, secondly, paragraph 24 of those decisions mention that criterion as an integral part of the concept of aid.

226It should be pointed out that the Commission proceeds in the same way in its written pleadings in the course of the proceedings, in which it avoids taking a position on the criterion of whether the measure was attributable to the State and defending itself specifically against the complaints put forward in support of the second plea in law. Instead, it focuses on its response to the third plea relating to the existence of an advantage while arguing that it is sufficient that one of the criteria constituting the concept of aid is not satisfied to justify the adoption of a decision under Article 4(2) of Regulation 2015/1589. Finally, at the hearing, even in response to a specific question put by the Court in that regard, the Commission adopted a similar approach.

227With regard to the criterion of whether the measure was attributable to the State, it is appropriate to recall the settled case-law according to which, for it to be possible to classify advantages as ‘State aid’ within the meaning of Article 107(1) TFEU, they must be granted directly or indirectly through State resources and be attributable to the State. In order to assess whether a measure is attributable to the State, it is necessary to examine whether the public authorities were involved in the adoption of that measure (see, to that, effect, judgment of 13 September 2017, ENEA, C‑329/15, EU:C:2017:671, paragraphs 20 and 21 and the case-law cited).

228Thus, in cases where national legislation prescribed an obligation to supply or purchase electricity or a mechanism to support and compensate for the costs of producing electricity which influenced the amount of its tariff, it has been consistently held that the corresponding obligations were a measure attributable to the State (see, to that effect, judgments of 19 December 2013, Association Vent De Colère! and Others, C‑262/12, EU:C:2013:851, paragraphs 16 to 18; of 13 September 2017, ENEA, C‑329/15, EU:C:2017:671, paragraphs 20 to 22; and of 15 May 2019, Achema and Others, C‑706/17, EU:C:2019:407, paragraphs 47 to 49).

229In the present case, only the pricing criteria for the supply of electricity to high-voltage customers and not the precise amount of tariffs are laid down in the applicable Greek legislation, namely, inter alia, in the context of the ‘basic principles for electricity pricing in Greece’, established in Decision No 692/2011 of the RAE (see paragraph 8 above). With regard to the determination of the amount of the applicable tariffs in accordance with those principles, Article 37 of Law No 4001/2011 provides only for the possibility for the contracting parties to have recourse to permanent arbitration by the RAE, which gave rise, in the present case, to the adoption of Decision No 346/2012 of the RAE of 9 May 2012 setting an interim tariff and the adoption of the arbitration award fixing the tariff in question, which applies to the transactional relationships between the applicant and the intervener (see paragraphs 9 and 12 above). The lack of binding rules on the tariffs for the supply of electricity in Greece is confirmed by the procedure initiated before the EEA which concerned an alleged abuse of a dominant position by the applicant seeking to charge the intervener excessive and discriminatory tariffs and which led the EEA to accept behavioural commitments offered by the applicant (see paragraph 13 above). It follows that it is that award, as confirmed by the Efetio Athinon (Court of Appeal, Athens) in its Judgment No 634/2016 of 18 February 2016, which imposed the tariff in question on the applicant in a legally binding manner.

230With regard to the question as to whether the arbitration award is an act of public authority that can be attributed to the Greek State, it is sufficient to recall the factors set out in paragraphs 150 to 158 above in order to find that the applicant has demonstrated to the requisite legal standard that that was the case.

231Those factors establish that, by its nature and legal effects, the arbitration award is comparable to judgments delivered by an ordinary Greek court, and therefore it must be classified as an act of a public authority. This is demonstrated in particular by the fact that it was the subject of an appeal before the Efetio Athinon (Court of Appeal, Athens). It also follows that the arbitration tribunals established and operating in accordance with Article 37 of Law No 4001/2011, like the ordinary Greek courts whose place they may take, form an integral part of the Greek State’s system of judicial protection.

232The Commission therefore erred in concluding, in the contested letter, first, that it had not been demonstrated by the applicant that ‘the arbitration tribunal is a body exercising State authority, especially since both [the applicant] and [the intervener] resorted voluntarily to arbitration, without any legal obligation to that end’ and, secondly, that ‘the [Greek] State does not seem to have had the possibility to dictate the decision of the arbitration tribunal’. The fact that the parties have referred the dispute to an arbitration tribunal voluntarily or by mutual agreement, as in the present case, is not a relevant criterion for differentiation in that regard, since even the bringing of proceedings before an ordinary Greek court would also have been voluntary.

233That conclusion is sufficient to take the view that the Commission ought to have had serious difficulties or doubts as to the existence of State aid or, at the very least, that it was not entitled to dismiss such doubts on the ground that the arbitration award was not attributable to the Greek State. This is all the more true given that State aid may also be granted through or with the intervention of a State court which fails to comply with its obligations under Article 108(3) TFEU (see the case-law cited in paragraph 147 above).

234Accordingly, the present plea in law must be upheld, without there being any need to rule on the other complaints put forward in support of it.

235Consequently, since the first and second pleas in law must be upheld, the contested letter must be annulled, without there being any need to rule on the other pleas.

E. Conclusion in Joined Cases T‑639/14 RENV, T‑352/15 and T‑740/17

236It follows from all of the foregoing considerations that the actions in Joined Cases T‑639/14 RENV, T‑352/15 and T‑740/17 must be upheld and the contested acts annulled, without there being any need to rule on the admissibility of the applicant’s observations on the report for the hearing, including the annexes thereto, in so far as they may contain new and belated offers of evidence in accordance with Article 85 of the Rules of Procedure, and on the applicant’s request to reopen the oral part of the procedure.

IV. Costs

237Under Article 134(1) of the Rules of Procedure, the unsuccessful party is to be ordered to pay the costs if they have been applied for in the successful party’s pleadings. Since the Commission has been unsuccessful, it must be ordered to pay the costs, in accordance with the form of order sought by the applicant.

238Under Article 138(3) of the Rules of Procedure, the Court may order an intervener other than those referred to in paragraphs 1 and 2 of that article to bear its own costs. In the present case, it is appropriate to decide that the intervener shall bear its own costs.

Operative part

On those grounds,THE GENERAL COURT (Third Chamber, Extended Composition),hereby:

1.In Case T‑639/14 RENV, annuls the Commission’s letter COMP/E3/ΟΝ/AB/ark *2014/61460 of 12 June 2014 informing Dimosia Epicheirisi Ilektrismou AE (DEI) of the closure of its complaints;

2.In Case T‑352/15, annuls Commission Decision C(2015) 1942 final of 25 March 2015 (Case SA.38101 (2015/NN) (ex 2013/CP) – Greece – Alleged State aid to Alouminion SA in the form of electricity tariffs below cost following an arbitration decision);

3.In Case T‑740/17, annuls Commission Decision C(2017) 5622 final of 14 August 2017 (Case SA.38101 (2015/NN) (ex 2013/CP) – Greece – Alleged State aid to Alouminion SA in the form of electricity tariffs below cost following an arbitration decision);

4.Orders the European Commission to bear its own costs and to pay those incurred by DEI in Joined Cases T‑639/14 RENV, T‑352/15 and T‑740/17, and also in Case C‑228/16 P;

5.Orders Mytilinaios AE – Omilos Epicheiriseon to bear its own costs.

Delivered in open court in Luxembourg on 22 September 2021.