ORDER OF THE COURT (Eighth Chamber)
6 May 2026 (*)
( Appeal – Article 181 of the Rules of Procedure of the Court of Justice – Second paragraph of Article 56 of the Statute of the Court of Justice of the European Union – Appeal brought by a party which was not unsuccessful in its submissions at first instance – Appeal manifestly inadmissible )
In Case C‑849/25 P,
APPEAL under Article 56 of the Statute of the Court of Justice of the European Union, brought on 17 December 2025,
Swissgrid AG, established in Aarau (Switzerland), represented by P. De Baere,
A. Kavoosi,
P. L’Ecluse, V. Lefever and K. T’Syen, avocats,
appellant,
the other parties to the proceedings being:
European Union Agency for the Cooperation of Energy Regulators (ACER),
defendant at first instance,
European Commission,
intervener at first instance,
THE COURT (Eighth Chamber),
composed of O. Spineanu-Matei, President of the Chamber, S. Rodin and N. Fenger (Rapporteur), Judges,
Advocate General: M. Szpunar,
Registrar: A. Calot Escobar,
having decided, after hearing the Advocate General, to rule by reasoned order, pursuant to Article 181 of the Rules of Procedure of the Court of Justice,
makes the following
Order
1        By its appeal, Swissgrid AG asks the Court of Justice to set aside, first, the judgment of the General Court of the European Union of 8 October 2025, Swissgrid v ACER (T‑556/23, ‘the judgment under appeal’, EU:T:2025:941), in so far as it rejected the first plea in its action at first instance, and, second, Decision A‑009‑2022 of the Board of Appeal of the European Union Agency for the Cooperation of Energy Regulators (ACER) of 29 June 2023 dismissing as inadmissible the appeal against Decision 16/2022 of ACER of 30 September 2022 (‘the decision at issue’).
Legal context
2        The first and second paragraphs of Article 56 of the Statute of the Court of Justice of the European Union provide:
‘An appeal may be brought before the Court of Justice, within two months of the notification of the decision appealed against, against final decisions of the General Court and decisions of that Court disposing of the substantive issues in part only or disposing of a procedural issue concerning a plea of lack of competence or inadmissibility.
Such an appeal may be brought by any party which has been unsuccessful, in whole or in part, in its submissions. However, interveners other than the Member States and the institutions of the [European] Union may bring such an appeal only where the decision of the General Court directly affects them.’
Background to the dispute
3        The background to the dispute is set out in paragraphs 1 to 12 of the judgment under appeal and may be summarised as follows.
4        Swissgrid, a public limited liability company incorporated under Swiss law, is Switzerland’s sole electricity transmission system operator (‘TSO’).
5        Since 2012, that company has participated in the International Grid Control Cooperation (IGCC), a structure for cooperation among TSOs the purpose of which is to optimise the automated operation of frequency restoration reserves through an imbalance netting process. In 2016, 11 TSOs, including Swissgrid, concluded the multilateral agreement on the IGCC, which governed the arrangements for their cooperation.
6        The European Commission adopted Regulation (EU) 2017/2195 of 23 November 2017 establishing a guideline on electricity balancing (OJ 2017 L 312, p. 6), which provides for the establishment of common European platforms for operating the imbalance netting process and enabling the exchange of balancing energy from frequency restoration reserves and replacement reserves, and in particular, in Article 22, a European platform for the imbalance netting process.
7        In December 2019, the member TSOs of the multilateral agreement on the IGCC, including Swissgrid, entered into an agreement on the IGCC, which replaces the multilateral agreement referred to in paragraph 5 of the present order. That cooperation agreement is subordinated to a principal agreement regarding the balancing platforms, common to all the platforms, which entered into force on 1 July 2020.
8        On 24 June 2020, ACER adopted Decision 13/2020 on the creation of a European platform for the imbalance netting process, including, in the annex to that decision, the framework for implementing that platform.
9        On 30 September 2022, ACER adopted Decision 16/2022 amending that implementation framework. Article 1(b) of Annex I to that decision amended the definition of ‘member TSO’ set out in Article 2(1)(j) of that implementation framework so that it now refers to ‘any TSO to which Regulation [2017/2195] applie[d] and which [had] joined the [European platform for the imbalance netting process], including TSOs from multi-TSO [load-frequency control] areas’.
10      On 30 November 2022, Swissgrid lodged an appeal against that decision with the Board of Appeal of ACER.
11      By the decision at issue, the Board of Appeal held that Decision 16/2022 did not constitute an act capable of affecting Swissgrid’s legal position with the result that there was no further need to examine whether that decision was of direct and individual concern to the appellant within the meaning of Article 28(1) of Regulation (EU) 2019/942 of the European Parliament and of the Council of 5 June 2019 establishing a European Union Agency for the Cooperation of Energy Regulators (OJ 2019 L 158, p. 22) and, accordingly, dismissed its appeal as inadmissible.
The procedure before the General Court and the judgment under appeal
12      By application lodged at the Registry of the General Court on 8 September 2023, Swissgrid brought an action seeking annulment of the decision at issue and an order that ACER pay the costs of the proceedings.
13      In support of its action, Swissgrid relied on three pleas in law, alleging, first, an error of law in the interpretation of Regulation 2017/2195, second, an error of law as regards the Board of Appeal’s finding that the action against Decision 16/2022 was inadmissible, and the third, submitted in the alternative, alleging that Regulation 2017/2195 is unlawful.
14      By the judgment under appeal, the General Court, after rejecting the first plea, upheld the second plea and, without examining the third plea, annulled the decision at issue and ordered ACER to pay the costs in favour of Swissgrid.
Form of order sought by the appellant
15      By its appeal, Swissgrid asks the Court of Justice to set aside the judgment under appeal on the ground that the first plea in law in the action has been rejected.
16      In support of its appeal, Swissgrid relies on three grounds of appeal, alleging, first, that the General Court erred in law in finding that Regulation 2017/2195 contained a ‘rule of principle’ excluding Swissgrid from participation in the European platform for the imbalance netting process and other balancing energy platforms provided for by that regulation, second, that the General Court breached the principle of legal certainty, and third, that the statement of reasons in the judgment under appeal was insufficient and that the reasoning on which it is based is contradictory.
The appeal
17      Under Article 181 of the Rules of Procedure of the Court of Justice, where the appeal is, inter alia, in whole or in part, manifestly inadmissible, the Court may at any time, acting on a proposal from the Judge-Rapporteur and after hearing the Advocate General, decide by reasoned order to dismiss that appeal in whole or in part.
18      That provision must be applied in the present case.
19      It should be borne in mind that, in accordance with the second paragraph of Article 56 of the Statute of the Court of Justice of the European Union, an appeal may be brought, inter alia, against final decisions of the General Court by any party which has been unsuccessful, in whole or in part, in its submissions before the General Court.
20      The submissions of the parties to the proceedings are, in principle, upheld or rejected in the operative part of a judgment. Thus, Article 169(1) of the Rules of Procedure requires an appeal to seek to have set aside, in whole or in part, the decision of the General Court, as set out in the operative part of that decision (judgment of 25 July 2018, Société des produits Nestlé and Others v Mondelez UK Holdings & Services, C‑84/17 P, C‑85/17 P and C‑95/17 P, EU:C:2018:596, paragraph 40).
21      In that regard, it should be noted that, as stated in paragraph 12 of the present order, Swissgrid’s action before the General Court sought annulment of the decision at issue and an order that ACER pay the costs of the proceedings.
22      In its appeal, Swissgrid states that, of the three pleas which it relied on in its application for annulment before the General Court, only the first is relevant to the present appeal.
23      It submits that, since the General Court rejected that first plea, it clearly has an interest in bringing an appeal against the judgment under appeal.
24      However, although in the part of the judgment under appeal referred to in Swissgrid’s appeal, the General Court rejected Swissgrid’s first plea in law in support of its application for annulment of the decision at issue, it upheld Swissgrid’s second plea and ultimately upheld Swissgrid’s claim for annulment, since, as is apparent from the operative part of the judgment under appeal, it annulled the decision at issue in its entirety and ordered ACER to pay the costs.
25      Consequently, in so far as the General Court upheld all the submissions made by Swissgrid in its application at first instance, Swissgrid is not entitled to bring an appeal before the Court of Justice against the judgment under appeal. The condition laid down in the second paragraph of Article 56 of the Statute of the Court of Justice of the European Union, according to which any party which has been unsuccessful, in whole or in part, in its submissions before the General Court is entitled to bring an appeal before the Court of Justice, is not satisfied (see, to that effect, order of 29 April 2022, Valvis Holding v Sun Stars & Sons and EUIPO, C‑420/21 P, EU:C:2022:340, paragraph 21). Moreover, an appeal cannot, in reality, seek to amend certain grounds of the judgment under appeal, failing which it will be inadmissible (see, to that effect, judgment of 25 July 2018, Société des produits Nestlé and Others v Mondelez UK Holdings & Services, C‑84/17 P, C‑85/17 P and C‑95/17 P, EU:C:2018:596, paragraph 42 and the case-law cited).
26      It follows that the appeal must be dismissed as manifestly inadmissible.
Costs
27      Under Article 137 of the Rules of Procedure, applicable to appeal proceedings by virtue of Article 184(1) of those rules, a decision as to costs is to be given in the order which closes the proceedings.
28      Since the present order was adopted before the appeal was served on the other party to the proceedings and, therefore, before it could have incurred costs, it is appropriate to decide that the appellant is to bear its own costs.
On those grounds, the Court (Eighth Chamber) hereby orders:
1.      The appeal is dismissed as manifestly inadmissible.
2.      Swissgrid AG shall bear its own costs.
Luxembourg, 6 May 2026.
A. Calot Escobar
O. Spineanu-Matei
Registrar
President of the Chamber
*      Language of the case: English.