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Baltic Cable AB, by M. Wärnsby, L. Hallberg and S. Andersson, advokater,

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the Energimarknadsinspektionen, by G. Morén, C. Vendel Nylander, R. Thuresson and E. Vidlund, acting as Agents,

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the Spanish Government, initially by A. Rubio González, and subsequently by L. Aguilera Ruiz, acting as Agents,

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the Finnish Government, by S. Hartikainen, acting as Agent,

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the European Parliament, by I. McDowell and A. Neergaard, acting as Agents,

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the Council of the European Union, by A. Lo Monaco, J. Kneale and A. Norberg, acting as Agents,

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the European Commission, by O. Beynet and K. Simonsson, acting as Agents,

1

This request for a preliminary ruling concerns the interpretation and the validity of Article 16(6) of Regulation (EC) No 714/2009 of the European Parliament and of the Council of 13 July 2009 on conditions for access to the network for cross-border exchanges in electricity, and repealing Regulation (EC) No 1228/2003 (OJ 2009 L 211 p. 15).

2

The request has been brought in proceedings between Baltic Cable AB and the Energimarknadsinspektionen (Swedish Energy Markets Inspectorate; ‘the EI’) concerning the use of revenues, resulting from the allocation of capacity of a cross-border high-voltage power line connecting the Swedish and German transmission networks to each other, received by Baltic Cable.

3

Recitals 44 and 59 of Directive 2009/72/EC of the European Parliament and of the Council of 13 July 2009 concerning common rules for the internal market in electricity and repealing Directive 2003/54/EC (OJ 2009 L 211, p. 55) state:

…

4

According to Article 1 thereof, Directive 2009/72 ‘establishes common rules for the generation, transmission, distribution and supply of electricity, together with consumer protection provisions, with a view to improving and integrating competitive electricity markets in the [European Union]’.

5

Article 2 of Directive 2009/72 provides:

‘For the purposes of this Directive, the following definitions shall apply:

…

…

…’

6

Under Article 12(a) and (h) of that directive:

‘Each transmission system operator shall be responsible for:

…

7

Article 13(4) of Directive 2009/72 provides:

‘Each independent system operator shall be responsible for granting and managing third-party access, including the collection of access charges, congestion charges, and payments under the inter-transmission system operator compensation mechanism in compliance with Article 13 of Regulation … No 714/2009, as well as for operating, maintaining and developing the transmission system, and for ensuring the long-term ability of the system to meet reasonable demand through investment planning. …’

8

Article 37(3) and (9) of that directive provides:

‘3.   In addition to the duties conferred upon it under paragraph 1 of this article, when an independent system operator has been designated under Article 13, the regulatory authority shall:

…

…

9.   The regulatory authorities shall monitor congestion management of national electricity systems including interconnectors, and the implementation of congestion management rules. To that end, transmission system operators or market operators shall submit their congestion management rules, including capacity allocation, to the national regulatory authorities. National regulatory authorities may request amendments to those rules.’

9

Recitals 21 and 24 of Regulation No 714/2009 state:

…

10

As set out in Article 1(a) of that regulation:

‘This Regulation aims at:

11

Article 2(1) of that regulation provides:

‘For the purpose of this Regulation, the definitions contained in Article 2 of [Directive 2009/72] apply, with the exception of the definition of “interconnector” which shall be replaced by the following:

12

Article 2(2)(c) of Regulation No 714/2009 defines ‘congestion’ as ‘a situation in which an interconnection linking national transmission networks cannot accommodate all physical flows resulting from international trade requested by market participants, because of a lack of capacity of the interconnectors and/or the national transmission systems concerned’.

13

Under Article 2(2)(g) of that regulation, a ‘new interconnector’ is defined as an interconnector not completed by 4 August 2003.

14

According to Article 14(1) and (4) of Regulation No 714/2009:

‘1.   Charges applied by network operators for access to networks shall be transparent, take into account the need for network security and reflect actual costs incurred in so far as they correspond to those of an efficient and structurally comparable network operator and are applied in a non-discriminatory manner. Those charges shall not be distance-related.

…

4.   Setting the charges for network access under this Article shall be without prejudice to charges on declared exports and declared imports resulting from congestion management referred to in Article 16.’

15

Article 16 of that regulation, headed ‘General principles of congestion management’, provides:

‘1.   Network congestion problems shall be addressed with non-discriminatory market-based solutions which give efficient economic signals to the market participants and transmission system operators involved. Network congestion problems shall preferentially be solved with non-transaction based methods, i.e. methods that do not involve a selection between the contracts of individual market participants.

2.   Transaction curtailment procedures shall only be used in emergency situations where the transmission system operator must act in an expeditious manner and re-dispatching or countertrading is not possible. Any such procedure shall be applied in a non-discriminatory manner.

Except in cases of force majeure, market participants who have been allocated capacity shall be compensated for any curtailment.

3.   The maximum capacity of the interconnections and/or the transmission networks affecting cross-border flows shall be made available to market participants, complying with safety standards of secure network operation.

4.   Market participants shall inform the transmission system operators concerned a reasonable time in advance of the relevant operational period whether they intend to use allocated capacity. Any allocated capacity that will not be used shall be reattributed to the market, in an open, transparent and non-discriminatory manner.

5.   Transmission system operators shall, as far as technically possible, net the capacity requirements of any power flows in opposite direction over the congested interconnection line in order to use that line to its maximum capacity. Having full regard to network security, transactions that relieve the congestion shall never be denied.

6.   Any revenues resulting from the allocation of interconnection shall be used for the following purposes:

If the revenues cannot be efficiently used for the purposes set out in points (a) and/or (b) of the first subparagraph, they may be used, subject to approval by the regulatory authorities of the Member States concerned, up to a maximum amount to be decided by those regulatory authorities, as income to be taken into account by the regulatory authorities when approving the methodology for calculating network tariffs and/or fixing network tariffs.

The rest of revenues shall be placed on a separate internal account line until such time as it can be spent on the purposes set out in points (a) and/or (b) of the first subparagraph. The regulatory authority shall inform the Agency of the approval referred to in the second subparagraph.’

16

Under Article 17(1) and (3) of Regulation No 714/2009:

‘1.   New direct current interconnectors may, upon request, be exempted, for a limited period of time, from the provisions of Article 16(6) of this Regulation and Articles 9, 32 and Article 37(6) and (10) of Directive [2009/72] under the following conditions:

…

3.   Paragraph 1 shall also apply to significant increases of capacity in existing interconnectors.’

17

Annex I to Regulation No 714/2009, entitled ‘Guidelines on the management and allocation of available transfer capacity of interconnections between national systems’, provides, inter alia:

‘1.7. … TSOs [(transmission system operators)] shall not limit interconnection capacity in order to solve congestion inside their own control area, save for the abovementioned reasons and reasons of operational security. …

…

2.1. Congestion-management methods shall be market-based in order to facilitate efficient cross-border trade. For that purpose, capacity shall be allocated only by means of explicit (capacity) or implicit (capacity and energy) auctions. Both methods may coexist on the same interconnection. For intra-day trade continuous trading may be used.

…

2.6. TSOs shall define an appropriate structure for the allocation of capacity between different timeframes. …

…

3.1. Capacity allocation at an interconnection shall be coordinated and implemented using common allocation procedures by the TSOs involved. …

…

5.2. TSOs shall publish a general description of the congestion-management method applied under different circumstances for maximising the capacity available to the market, and a general scheme for the calculation of the interconnection capacity for the different timeframes, based upon the electrical and physical realities of the network. Such a scheme shall be subject to review by the regulatory authorities of the Member States concerned.’

18

Point 6 of that annex, headed ‘Use of congestion income’, states as follows:

‘…

6.3. The congestion income shall be shared among the TSOs involved in accordance with criteria agreed between the TSOs involved and reviewed by the respective regulatory authorities.

6.4. TSOs shall clearly establish beforehand the use they will make of any congestion income they may obtain and report on the actual use of that income. Regulatory authorities shall verify that such use complies with this Regulation and those Guidelines and that the total amount of congestion income resulting from the allocation of interconnection capacity is devoted to one or more of the three purposes set out in Article 16(6) of this Regulation.

…

6.6. The use of congestion income for investment to maintain or increase interconnection capacity shall preferably be assigned to specific predefined projects which contribute to relieving the existing associated congestion and which may also be implemented within a reasonable time, particularly as regards the authorisation process.’

19

Baltic Cable is a Swedish company which has owned and operated since 1994 a high-voltage electricity cable which connects the Swedish and German transmission networks.

20

By decision of 9 June 2016, the EI, on the basis of the first subparagraph of Article 16(6) of Regulation No 714/2009, asked Baltic Cable to place its congestion revenues, that is to say those revenues resulting from the allocation of capacity of that interconnection, for the periods from 1 July 2013 to 30 June 2014 and from 1 July 2014 to 30 June 2015, on a separate internal account line until such time as the company could use the revenues to guarantee the actual availability of the allocated capacity and/or to maintain or increase interconnection capacities through network investments, in particular in new interconnectors.

21

By decision of 2 November 2017, the EI refused Baltic Cable’s request, made under the second subparagraph of Article 16(6) of Regulation No 714/2009, for permission to use its congestion revenues as revenues to be taken into account by the regulatory authorities when approving the method for calculating network access tariffs and/or fixing those network tariffs.

22

Baltic Cable brought an action against those two decisions before the Förvaltningsrätten i Linköping (Administrative Court, Linköping, Sweden). It claims, primarily, that Article 16 of Regulation No 714/2009 relates exclusively to TSOs within the meaning of Article 2(4) of Directive 2009/72 and not companies which, like Baltic Cable, merely operate an interconnector.

23

Baltic Cable claims, in the alternative, that Article 16(6) of Regulation No 714/2009 must be construed as meaning that companies merely operating an interconnector are free to dispose, as they wish, of all the congestion revenues resulting from the interconnector in which they have invested.

24

In any event, it claims that those companies should be allowed to use their congestion revenues in accordance with the second subparagraph of Article 16(6) of Regulation No 714/2009.

25

Lastly, Baltic Cable claims that, since its congestion revenues represent around 70% of its revenues, the EI’s decisions referred to in paragraphs 20 and 21 above are contrary to the right of ownership. In addition, those decisions fail to observe the principle of proportionality by disproportionately impairing Baltic Cable’s ability to pursue its business and by undermining the objectives pursued by Regulation No 714/2009 to effectively maintain interconnection capacity, even though there are less restrictive means of meeting those objectives by making use of the possibilities provided for by the second subparagraph of Article 16(6) of that regulation. Lastly, those decisions fail to observe the principle of the protection of legitimate expectations in so far as, by previously deciding on the revenue caps for Baltic Cable, the EI had accepted how Baltic Cable intended to use the congestion revenues.

26

The EI contends that Article 16(6) of Regulation No 714/2009 is directed at all persons that receive congestion revenues and that, as a result, Baltic Cable is subject to that provision as regards the use of its congestion revenues.

27

In the alternative, should Article 16(6) of Regulation No 714/2009 apply purely to TSOs, the EI asserts that Baltic Cable should be considered to be a TSO.

28

It submits, in addition, that, since Baltic Cable does not have customers paying network tariffs, it cannot enjoy the derogations provided for in the second subparagraph of Article 16(6) of Regulation No 714/2009 which involve, in effect, a reduction of those tariffs.

29

While acknowledging that applying Article 16(6) of Regulation No 714/2009 to Baltic Cable would have consequences for the latter that could be considered to be disproportionate, the EI takes the view that that fact does not give it the authority to apply that provision contra legem.

30

The referring court takes the view that, in the light of the wording of Article 16(6) of Regulation No 714/2009, its scope is not limited only to TSOs, even though an interpretation to the contrary cannot automatically be ruled out.

31

According to that court, it is also clear from points (a) and (b) of the first subparagraph of Article 16(6) of Regulation 714/2009 that an undertaking which operates an interconnector may not use its congestion revenues to make a return. By contrast, a broad interpretation of that provision could authorise the use of those revenues for the purposes of the operation and maintenance of that interconnector.

32

The referring court is nevertheless uncertain whether the second subparagraph of Article 16(6) of Regulation No 714/2009 allows a national authority to authorise a company, such as Baltic Cable, which does not have customers paying network tariffs that could be reduced, to use its congestion revenues for purposes other than those referred to in the first subparagraph of Article 16(6) of that regulation.

33

Lastly, in the event that Article 16(6) of Regulation No 714/2009 does apply to a company such as Baltic Cable, the referring court questions the validity of that provision in the light of the principle of proportionality.

34

In those circumstances, taking the view that the dispute before it raises questions of interpretation and validity of EU law, the Förvaltningsrätten i Linköping (Administrative Court, Linköping) decided to stay the proceedings and to refer the following questions to the Court of Justice for a preliminary ruling:

35

By its first and second questions, which should be examined together, the referring court asks, in essence, whether Article 16(6) of Regulation No 714/2009 must be interpreted as applying to an undertaking which merely operates a cross-border interconnector.

36

The first subparagraph of Article 16(6) of Regulation No 714/2009 provides that congestion revenues are to be used to guarantee the actual availability of the allocated capacity and/or to maintain or increase interconnection capacities through network investments, in particular in new interconnectors.

37

Since that provision does not specify who is subject to such an obligation, it is necessary, for the purpose of interpreting that provision, to consider not only its wording but also the context in which it occurs and the objectives pursued by the rules of which it forms part (see, to that effect, judgment of 7 June 2005, VEMW and Others, C‑17/03, EU:C:2005:362, paragraph 41 and the case-law cited).

38

As regards the context of Article 16(6) of Regulation No 714/2009, it should be noted that almost all the provisions of Article 16 of that regulation — including paragraph 1 thereof, which, on account of its general content, introduces all the provisions of that Article 16 — refer expressly to TSOs, highlighting the various responsibilities they must take on in the context of congestion management, the latter expression covering, as is apparent from Article 2(2)(c) of Regulation No 714/2009, only situations concerning an interconnector, as defined in Article 2(1) of that regulation.

39

The wording of Article 16(6) of Regulation No 714/2009 in no way indicates that that provision should fall outside the general scheme of Article 16. It follows from this that that provision must be regarded as concerning only TSOs.

40

That interpretation is supported by Annex I to Regulation No 714/2009, entitled ‘Guidelines on the management and allocation of available transfer capacity of interconnections between national systems’, the provisions of which, in turn, refer systematically to TSOs. In particular, point 1.7 of that annex provides that TSOs are not to limit interconnection capacity in order to solve congestion inside their own control areas, while point 5.2 of that annex states that TSOs are to publish a general description of the congestion-management method applied under different circumstances for maximising the capacity available to the market, and a general scheme for the calculation of the interconnection capacity for the different time frames. It is also apparent from points 1.7, 2.6 and 3.1 of the same annex that TSOs are responsible for capacity allocation of interconnectors.

41

It follows, moreover, as Article 12(h), Article 13(4) and Article 37(3)(f) of Directive 2009/72 confirm, that congestion revenues are collected by the TSOs which are thus required to use them in accordance with Article 16(6) of Regulation No 714/2009.

42

In these circumstances, it is necessary to examine whether the concept of TSO within the meaning of Regulation No 714/2009 extends to undertakings merely operating an interconnector.

43

In that regard, as regards, first of all, the concept of ‘interconnector’, Article 2(1) of Regulation No 714/2009 defines this, inter alia, as ‘a transmission line’ connecting ‘the national transmission systems of the Member States’. It follows that, as regards electricity transmission, the regulation distinguishes between an interconnector and a network, the first being not a transmission ‘system’ but a transmission ‘line’.

44

Next, according to Article 2(4) of Directive 2009/72, which, under Article 2(1) of Regulation No 714/2009, applies for the purposes of that regulation, a TSO is a natural or legal person responsible for operating, ensuring the maintenance of and, if necessary, developing the transmission system in a given area and, where applicable, its interconnections with other systems, and for ensuring the long-term ability of the system to meet reasonable demands for the transmission of electricity.

45

It follows from this that the concept of TSO covers a person which is responsible, inter alia, for operating and maintaining not only a transmission system but also, where applicable, one or more interconnectors.

46

Lastly, having regard to the wording of Article 2(4) of Directive 2009/72, it appears that the EU legislature did not explicitly envisage the case in which a TSO operates merely a ‘transmission line’, thus including an interconnector. For that reason, there is no basis to consider that the EU legislature intended to exclude from the concept of TSO within the meaning of that provision and from Regulation No 714/2009 an operator that operates and maintains only one or more interconnectors.

47

First of all, it should be noted that the definition of TSO, referred to in paragraph 44 above, puts the emphasis on the responsibility of the person concerned as regards operating, ensuring the maintenance of and, if necessary, developing the infrastructure creating electricity, irrespective of whether that infrastructure constitutes a ‘system’ or a ‘line’.

48

Next, Article 17 of Regulation No 714/2009, which exempts new interconnectors from the provisions of Article 16(6) of that regulation, provides, in paragraph 1(c) thereof, that, in order to benefit from that exemption, the interconnector in question must be owned by a natural or legal person which is separate from the system operators in whose systems that interconnector will be built. It is apparent from the preparatory works for Regulation (EC) No 1228/2003 of the European Parliament and of the Council of 26 June 2003 on conditions for access to the network for cross-border exchanges in electricity (OJ 2003 L 176, p. 1), which was repealed and replaced by Regulation No 714/2009, in particular from the explanatory memorandum to the amended Proposal for a Regulation of the European Parliament and of the Council on conditions for access to the network for cross-border exchanges in electricity (COM(2002) 304 final), that that provision is aimed at interconnectors where the investor cannot rely on charges made for the use of the networks linked by the interconnector.

49

It follows that the EU legislature necessarily started from the premiss that undertakings merely operating an interconnector are covered by the scope of Article 16(6) of Regulation No 714/2009.

50

Lastly, activity which is limited to operating and maintaining an interconnector participates in cross-border trade and is therefore likely to enhance competition on the internal market for electricity. As a result, excluding such activity from the concept of TSO would defeat the purpose of Regulation No 714/2009 as defined in Article 1(a) thereof.

51

It follows that the concept of TSO within the meaning of Regulation No 714/2009 extends to undertakings merely operating a cross-border interconnector.

52

In the light of all the foregoing considerations, the answer to the first and second questions is that Article 16(6) of Regulation No 714/2009 must be interpreted as applying to an undertaking which merely operates a cross-border interconnector.

53

By its third question, the referring court asks, in essence, whether Article 16(6) of Regulation No 714/2009 must be interpreted as meaning that, when a TSO merely operates a cross-border interconnector, the operation and maintenance costs of that interconnector may be regarded as network investments to maintain or increase interconnection capacities within the meaning of point (b) of the first subparagraph of Article 16(6) of Regulation No 714/2009.

54

As a preliminary remark, it should be borne in mind that, as is apparent from the heading of Article 16 of Regulation No 714/2009, the provisions of that article establish a set of rules relating to congestion management.

55

Congestion is defined in Article 2(2)(c) of Regulation No 714/2009 as a situation resulting from a lack of capacity of the interconnectors and/or the national transmission systems concerned.

56

In that regard, Article 16(6) of Regulation No 714/2009 governs the ‘revenues resulting from the allocation of interconnection’.

57

As is apparent from Article 1(a) of Regulation No 714/2009, that allocation of interconnection capacities is the subject of harmonised principles which must allow fair rules to be set for cross-border exchanges in electricity in order to enhance competition within the internal market for electricity. In accordance with point 2.1 of Annex I to that regulation, such allocation will be done by means of auctions.

58

It follows from the combined reading of all the provisions cited in paragraphs 54 to 57 above that the lower the available capacity of interconnection in relation to demand, the higher the revenues referred to in Article 16(6) of Regulation No 714/2009 are likely to be for the TSO concerned. Accordingly, and as the Advocate General noted in point 43 of his Opinion, the TSOs have, in principle, no economic incentive to reduce congestion.

59

In order to reduce or, at the very least, contain the congestion, the first subparagraph of Article 16(6) of Regulation No 714/2009 requires that congestion revenues be used, according to point (a), to guarantee the actual availability of the allocated capacity and/or, according to point (b), to maintain or increase interconnection capacities through network investments, in particular in new interconnectors.

60

In the present case, the referring court wishes, specifically, to ascertain the scope of point (b) of the first subparagraph of Article 16(6) of Regulation No 714/2009.

61

As is apparent from the wording of that provision, the EU legislature highlighted the need for the revenues covered by that provision, including those arising from the maintenance of existing interconnectors, to constitute an ‘investment’, whether an investment to increase interconnection capacities or an investment to maintain them. In that regard, point 6.6 of Annex I to Regulation No 714/2009 provides that the use of congestion income for such investment is preferably to be assigned to specific predefined projects which contribute to relieving the congestion at issue and which may also be implemented within a reasonable time, particularly as regards the authorisation process.

62

Therefore, the operation and maintenance costs of an interconnector, inasmuch as they do not constitute such investments, cannot come within the scope of point (b) of the first subparagraph of Article 16(6) of Regulation No 714/2009.

63

In the light of all the foregoing considerations, the answer to the third question is that point (b) of the first subparagraph of Article 16(6) of Regulation No 714/2009 must be interpreted as meaning that, when a TSO merely operates a cross-border interconnector, the operation and maintenance costs of that interconnector cannot be regarded as network investments to maintain or increase interconnection capacities within the meaning of that provision.

64

By its fourth question, the referring court asks, in essence, whether the second subparagraph of Article 16(6) of Regulation No 714/2009 must be interpreted as meaning that, when it applies that provision to a TSO that merely operates a cross-border interconnector, the national regulatory authority may authorise such a TSO to use its congestion revenues to make a return or to operate or maintain that interconnector.

65

Under the second subparagraph of Article 16(6) of Regulation No 714/2009, congestion revenues that cannot be efficiently used for guaranteeing the actual availability of the allocated capacity and/or maintaining or increasing interconnection capacities through network investments, in particular in new interconnectors, may be used, subject to approval by the regulatory authorities of the Member States concerned and up to a maximum amount to be decided by those regulatory authorities, as income to be taken into account by those authorities when approving the method for calculating network access tariffs and/or fixing those network tariffs.

66

In that regard, it is important to note, first of all, that, unlike TSOs merely responsible for an interconnector, TSOs that operate both an interconnector and a transmission system have, as is apparent from the very wording of point (b) of the first subparagraph of Article 16(6) of Regulation No 714/2009, the option of investing not only in that interconnector and/or new interconnectors but also in the transmission network itself since, as is implied by the definition of congestion set out in Article 2(2)(c) of Regulation No 714/2009, that network may be the cause of the congestion problems because of a lack of capacity.

67

Next, unlike TSOs merely operating an interconnector, a TSO that also operates a transmission network receives, in accordance with Article 14 of Regulation No 714/2009, charges for access to that network which, as is apparent from Article 17(1)(e) of Regulation No 714/2009, allows them to cover the maintenance and operating costs of the interconnector that it must bear. Those charges may also allow the TSOs that receive them to operate their business to make a return.

68

Lastly, the second subparagraph of Article 16(6) of Regulation No 714/2009 allows, subject to certain conditions, TSOs to use their congestion revenues to reduce network access charges. Yet, since they do not operate a transmission network and, accordingly, they do not receive such charges, TSOs merely operating an interconnector are unable to use their congestion revenues for the purposes envisaged by the second subparagraph of Article 16(6) of Regulation No 714/2009.

69

In order to draw conclusions from the differences set out in paragraphs 66 to 68 above, it is important, in the first place, to take into consideration Article 16(1) of Regulation No 714/2009, pursuant to which, inter alia, network congestion problems must be addressed with ‘non-discriminatory solutions’. That provision reflects the general principle of non-discrimination enshrined in Article 21 of the Charter of Fundamental Rights of the European Union.

70

Accordingly, Article 16(6) of Regulation No 714/2009 must be interpreted in the light of Article 16(1) of that regulation and the principle of non-discrimination, in order to ensure that, in applying Article 16(6), TSOs merely operating an interconnection are not subject to discriminatory treatment compared to those which also operate a transmission network.

71

In the second place, it should be noted that Article 16(6) of Regulation No 714/2009 must be interpreted in the light of recital 21 of that regulation, according to which it is possible to derogate from the rules on the use of congestion revenues if justified by the specific nature of the interconnector concerned.

72

In that regard, Article 17 of Regulation No 714/2009 allows new interconnectors to be exempted from the provisions of Article 16(6) of that regulation, while requiring, for that purpose, that certain specific conditions be satisfied, including the condition set out in Article 17(1)(c) of that regulation, which requires that the interconnector be owned by a natural or legal person separate from the TSOs in whose systems that interconnector will be built.

73

In this way, the EU legislature intended, as regards new interconnectors, to render the scope of the obligations flowing from point (b) of the first subparagraph of Article 16(6) of Regulation No 714/2009 more flexible, in particular in the event that an interconnector is managed by a TSO different from the TSOs that manage the networks linked by that interconnector.

74

Moreover, Article 17(3) of Regulation No 714/2009, pursuant to which paragraph 1 of that article applies to significant increases of capacity in existing interconnectors, means that the fact that the interconnector concerned is owned by a TSO different from those that own the networks that are linked by that interconnector is also relevant in order for it to be exempted from the rules, provided for in Article 16(6) of that regulation, on the use of congestion revenues from existing interconnectors.

75

In the third place, Article 16(1) of Regulation No 714/2009 requires that congestion problems be addressed with ‘market-based’ solutions.

76

For its part, Article 12(a) of Directive 2009/72 provides, inter alia, that each TSO is to carry out its activity ‘in financially acceptable conditions’.

77

However, the differences, set out in paragraphs 66 to 68 above, between a TSO that operates both a transmission network and an interconnector and a TSO that operates only an interconnector put the TSOs in the second category in a situation in which the congestion revenues they receive cannot, as envisaged by the second subparagraph of Article 16(6) of Regulation No 714/2009, be efficiently used for the purposes set out in points (a) and/or (b) of the first subparagraph of that same paragraph 6, since the allocation of the entirety of those revenues for those purposes would have the result of preventing those TSOs from carrying out their activity in financially acceptable conditions, since they would be unable to cover the operational and maintenance costs of the interconnector and to make an appropriate profit.

78

In view of the findings set out in paragraphs 69 to 77 above, the national regulatory authorities — which, as recital 24 of Regulation No 714/2009 shows, play an essential role in the proper functioning of the internal market in electricity — must, when they apply the second subparagraph of Article 16(6) of that regulation to a TSO merely operating an interconnector, put that TSO in a position in which it is able to carry out its activity in financially acceptable conditions, corresponding to the conditions of the electricity transmission market, which includes making an appropriate profit, in order, in particular, to prevent it being discriminated against by comparison with the other TSOs concerned. If necessary for those purposes, it is for that authority to authorise that TSO, by way of derogation from the first subparagraph of Article 16(6) of Regulation No 714/2009, to use part of the congestion revenues it receives in order to cover the maintenance and operating costs of the interconnector and to make an appropriate profit.

79

In the light of all the foregoing considerations, the answer to the fourth question is that the second subparagraph of Article 16(6) of Regulation No 714/2009 must be interpreted as meaning that, when a national regulatory authority applies that provision to a TSO that merely operates a cross-border interconnector, it is for that authority to authorise that TSO to use part of its congestion revenues to make a return as well as for the operation and maintenance of the interconnector, in order to prevent it being discriminated against by comparison with the other TSOs concerned and to ensure that it is in a position in which it is able to carry out its activity in financially acceptable conditions, which includes making an appropriate profit.

80

By its fifth question, the referring court asks, in essence, whether, in the circumstances stipulated in this question and in the event that Article 16(6) of Regulation No 714/2009 applies to a TSO that merely operates a cross-border interconnector, that provision must be considered to be contrary to the principle of proportionality or to any other general principle of Union law.

81

It is apparent from the wording of this question that the referring court asks this question only in the event that the answers to the previous questions mean that such a TSO may not use its congestion revenues to cover its operation and maintenance costs and/or to make a return.

82

In view of the Court’s answers to the first to the fourth questions, there is no need to answer the fifth question.

83

Since these proceedings are, for the parties to the main proceedings, a step in the action pending before the national court, the decision on costs is a matter for that court. Costs incurred in submitting observations to the Court, other than the costs of those parties, are not recoverable.

On those grounds, the Court (Third Chamber) hereby rules: