1 This request for a preliminary ruling concerns the interpretation of Article 16(2)(c) of Directive 2009/28/EC of the European Parliament and of the Council of 23 April 2009 on the promotion of the use of energy from renewable sources and amending and subsequently repealing Directives 2001/77/EC and 2003/30/EC (OJ 2009 L 140, p. 16), read in conjunction with Article 2(a) and (e) of that directive, and of the second subparagraph of Article 5(3) of that directive.
2 The request has been made in proceedings between EEW Energy from Waste Großräschen GmbH (‘EEW’) and MNG Mitteldeutsche Netzgesellschaft Strom GmbH (‘MNG Strom’) concerning loss suffered by EEW as a result of recurring requests from MNG Strom for access to the grids in respect of electricity produced by EEW.
3 Under Article 2(c) of Directive 2001/77/EC of the European Parliament and of the Council of 27 September 2001 on the promotion of electricity produced from renewable energy sources in the internal electricity market (OJ 2001 L 283, p. 33): ‘For the purposes of this Directive, the following definitions shall apply: … (c) “electricity produced from renewable energy sources” shall mean electricity produced by plants using only renewable energy sources, as well as the proportion of electricity produced from renewable energy sources in hybrid plants also using conventional energy sources and including renewable electricity used for filling storage systems, and excluding electricity produced as a result of storage systems’.
4 Recitals 11, 60 and 61 of Directive 2009/28, before being repealed by Directive (EU) 2018/2001 of the European Parliament and of the Council of 11 December 2018 on the promotion of the use of energy from renewable sources (OJ 2018 L 328, p. 82), were worded as follows: ‘(11) It is necessary to set transparent and unambiguous rules for calculating the share of energy from renewable sources and for defining those sources. … … (60) Priority access and guaranteed access for electricity from renewable energy sources are important for integrating renewable energy sources into the internal market in electricity, in line with Article 11(2) and developing further Article 11(3) of [Directive 2003/54/EC of the European Parliament and of the Council of 26 June 2003 concerning common rules for the internal market in electricity and repealing Directive 96/92/EC - Declarations on decommissioning and waste management operations (OJ 2003 L 176, p. 37)]. Requirements relating to the maintenance of the reliability and safety of the grid and to the dispatching may differ according to the characteristics of the national grid and its secure operation. Priority access to the grid provides an assurance given to connected generators of electricity from renewable energy sources that they will be able to sell and transmit the electricity from renewable energy sources in accordance with connection rules at all times, whenever the source becomes available. In the event that the electricity from renewable energy sources is integrated into the spot market, guaranteed access ensures that all electricity sold and supported obtains access to the grid, allowing the use of a maximum amount of electricity from renewable energy sources from installations connected to the grid. However, this does not imply any obligation on the part of Member States to support or introduce purchase obligations for energy from renewable sources. In other systems, a fixed price is defined for electricity from renewable energy sources, usually in combination with a purchase obligation for the system operator. In such a case, priority access has already been given. (61) In certain circumstances it is not possible fully to ensure transmission and distribution of electricity produced from renewable energy sources without affecting the reliability or safety of the grid system. In such circumstances it may be appropriate for financial compensation to be given to those producers. Nevertheless, the objectives of this Directive require a sustained increase in the transmission and distribution of electricity produced from renewable energy sources without affecting the reliability or safety of the grid system. To this end, Member States should take appropriate measures in order to allow a higher penetration of electricity from renewable energy sources, inter alia, by taking into account the specificities of variable resources and resources which are not yet storable. To the extent required by the objectives set out in this Directive, the connection of new renewable energy installations should be allowed as soon as possible. In order to accelerate grid connection procedures, Member States may provide for priority connection or reserved connection capacities for new installations producing electricity from renewable energy sources.’
5 Article 1 of Directive 2009/28, entitled ‘Subject matter and scope’, provided: ‘This Directive establishes a common framework for the promotion of energy from renewable sources. It sets mandatory national targets for the overall share of energy from renewable sources in gross final consumption of energy and for the share of energy from renewable sources in transport. It lays down rules relating to statistical transfers between Member States, joint projects between Member States and with third countries, guarantees of origin, administrative procedures, information and training, and access to the electricity grid for energy from renewable sources. …’
6 Article 2 of that directive provided: ‘For the purposes of this Directive, the definitions in Directive [2003/54] apply. The following definitions also apply: (a) “energy from renewable sources” means energy from renewable non-fossil sources, namely wind, solar, aerothermal, geothermal, hydrothermal and ocean energy, hydropower, biomass, landfill gas, sewage treatment plant gas and biogases; … (e) “biomass” means the biodegradable fraction of products, waste and residues from biological origin from agriculture (including vegetal and animal substances), forestry and related industries including fisheries and aquaculture, as well as the biodegradable fraction of industrial and municipal waste; … (j) “guarantee of origin” means an electronic document which has the sole function of providing proof to a final customer that a given share or quantity of energy was produced from renewable sources as required by Article 3(6) of Directive [2003/54]; …’
7 Article 5(1) and (3) of that directive was worded as follows: ‘1. The gross final consumption of energy from renewable sources in each Member State shall be calculated as the sum of: (a) gross final consumption of electricity from renewable energy sources; … 3. For the purposes of paragraph 1(a), gross final consumption of electricity from renewable energy sources shall be calculated as the quantity of electricity produced in a Member State from renewable energy sources, excluding the production of electricity in pumped storage units from water that has previously been pumped uphill. In multi-fuel plants using renewable and conventional sources, only the part of electricity produced from renewable energy sources shall be taken into account. For the purposes of this calculation, the contribution of each energy source shall be calculated on the basis of its energy content. The electricity generated by hydropower and wind power shall be accounted for in accordance with the normalisation rules set out in Annex II.’
8 Article 15(1) of the same directive provided as follows: ‘For the purposes of proving to final customers the share or quantity of energy from renewable sources in an energy supplier’s energy mix in accordance with Article 3(6) of Directive [2003/54], Member States shall ensure that the origin of electricity produced from renewable energy sources can be guaranteed as such within the meaning of this Directive, in accordance with objective, transparent and non-discriminatory criteria.’
9 Under Article 16(1) and (2) of Directive 2009/28: ‘1. Member States shall take the appropriate steps to develop transmission and distribution grid infrastructure, intelligent networks, storage facilities and the electricity system, in order to allow the secure operation of the electricity system as it accommodates the further development of electricity production from renewable energy sources, including interconnection between Member States and between Member States and third countries. Member States shall also take appropriate steps to accelerate authorisation procedures for grid infrastructure and to coordinate approval of grid infrastructure with administrative and planning procedures. 2. Subject to requirements relating to the maintenance of the reliability and safety of the grid, based on transparent and non-discriminatory criteria defined by the competent national authorities: (a) Member States shall ensure that transmission system operators and distribution system operators in their territory guarantee the transmission and distribution of electricity produced from renewable energy sources; (b) Member States shall also provide for either priority access or guaranteed access to the grid-system of electricity produced from renewable energy sources; (c) Member States shall ensure that when dispatching electricity generating installations, transmission system operators shall give priority to generating installations using renewable energy sources in so far as the secure operation of the national electricity system permits and based on transparent and non-discriminatory criteria. Member States shall ensure that appropriate grid and market-related operational measures are taken in order to minimise the curtailment of electricity produced from renewable energy sources. If significant measures are taken to curtail the renewable energy sources in order to guarantee the security of the national electricity system and security of energy supply, Members States shall ensure that the responsible system operators report to the competent regulatory authority on those measures and indicate which corrective measures they intend to take in order to prevent inappropriate curtailments.’
10 Paragraph 3, headed ‘Definitions’, of the Erneuerbare-Energien-Gesetz (German law on renewable energy) of 25 October 2008, in the version in force between 1 January 2012 and 31 July 2014 (‘the 2012 EEG’), provided: ‘For the purposes of the present law: 1. “installation” means any facility for producing electricity from renewable energy sources …; 3. “renewable energy” … means energy from biomass … and from the biodegradable fraction of industrial and municipal waste; …’
11 Paragraph 11 of the 2012 EEG, entitled ‘Feed-in management’, provided in paragraph 1: ‘… system operators shall be entitled, by way of exception, to regulate installations … directly or indirectly connected to their systems, in so far as …: (1) failure to do so would give rise to network congestion in the relevant part of the network, including the upstream network; (2) priority is given to electricity from renewable energy sources, … unless other installations for producing electricity must remain connected to the grid in order to ensure the security and reliability of the electricity supply system …; …’
12 Paragraph 12 of the 2012 EEG, entitled ‘Special provisions’, provided in paragraph 1: ‘If the feed-in of electricity from installations for producing electricity from renewable energy sources … is curtailed due to system congestion within the meaning of Paragraph 11(1), the operators affected by the measure shall be compensated … for 95% of the lost revenue plus any additional expenses incurred and less any expenses saved …’
13 It is apparent from the request for a preliminary ruling that those provisions of the 2012 EEG correspond, in essence, to those of the three versions of the EEG successively applicable to the dispute in the main proceedings.
14 EEW operates a waste thermal treatment installation in Großräschen (Germany) by means of which it produces electricity and thermal energy. Some of the waste, consisting of biodegradable waste, is treated by incineration at the same time as other types of waste. The proportion of biodegradable waste varies and can account for up to 50% of the total volume of waste. Part of the electricity produced by that installation feeds into the electricity distribution system operated by MNG Storm, to which EEW is bound by a connection and purchase agreement.
15 Between 2011 and 2016, MNG Strom, in the performance of its system security management tasks and, where appropriate, in consultation with 50 Hertz Transmission GmbH as transmission grid operator, instructed EEW on numerous occasions to curtail the feed-in of electricity temporarily due to system congestion. Consequently, EEW brought an action against MNG Strom, claiming compensation from it in the amount of EUR 2.24 million on the basis, inter alia, of Paragraph 12 of the 2012 EEG.
16 The appellate court dismissed EEW’s action on the ground that the electricity produced in EEW’s installation was not produced exclusively from renewable energy sources, with the result that that installation could not be classified as an ‘installation for the production of electricity from renewable energy sources’ within the meaning of the applicable national provisions.
17 EEW brought an appeal on a point of law (revision) against that decision before the Bundesgerichtshof (Federal Court of Justice, Germany), the referring court.
18 According to that court, the outcome of that action depends on the answer to the question whether EEW’s installation constitutes an ‘installation for producing electricity from renewable energy sources’ within the meaning of Paragraph 12 of the 2012 EEG, read in the light of Article 2(c) of Directive 2001/77 and the provisions of Directive 2009/28, in particular Article 16(2)(c) thereof.
19 In those circumstances, the Bundesgerichtshof (Federal Court of Justice) decided to stay the proceedings and to refer the following questions to the Court of Justice for a preliminary ruling: ‘(1) Is Article 16(2)(c) of Directive 2009/28/EC, read in conjunction with Article 2(a) and (e) thereof, to be interpreted as meaning that priority in respect of the feeding of electricity into the grid must also be given to generating installations in which electricity is produced by means of thermal recovery from mixed waste, whereby the waste contains a variable proportion of industrial and municipal biodegradable waste? (2) If Question 1 is answered in the affirmative, is the giving of priority in respect of the feed-in of electricity pursuant to Article 16(2)(c) of Directive 2009/28/EC dependent on the proportion of biodegradable waste used in the production of electricity in the manner described in Question 1? (3) If Question 2 is answered in the affirmative, is there a materiality threshold for the proportion of biodegradable waste below which the rules applicable to electricity from renewable energy sources do not apply to the electricity produced? (4) If Question 3 is answered in the affirmative, what is the level of that threshold, or how is the threshold to be determined? (5) If Questions 1 and 2 are answered in the affirmative, when applying the rules on electricity from renewable energy sources to electricity which has been produced only partly from biodegradable waste, can the legal rationale underlying the second subparagraph of Article 5(3) of Directive 2009/28/EC be applied in such a way that those rules apply only to the part of electricity produced from renewable energy sources, and that part is calculated on the basis of the energy content of the individual energy sources?’
20 By its first question, the referring court asks, in essence, whether Article 16(2)(c) of Directive 2009/28 must be interpreted as meaning that priority access to the electricity grid enjoyed by electricity generating installations using renewable energy sources must be granted not only to installations producing electricity exclusively from renewable energy sources, but also to those producing from both renewable and conventional energy sources.
21 Article 16(2)(c) of Directive 2009/28 provides that Member States are to ensure that, when dispatching electricity generating installations, transmission system operators give priority to generating installations using renewable energy sources in so far as the secure operation of the national electricity system permits and based on transparent and non-discriminatory criteria.
22 Although Article 2(a) of Directive 2009/28 defines the concept of ‘energy from renewable sources’ as including, inter alia, ‘biomass’ and, in Article 2(e), the concept of ‘biomass’ as including, inter alia, ‘the biodegradable fraction of industrial and municipal waste’, it does not, however, define the scope of the concept of ‘electricity generating installation using renewable energy sources’ within the meaning of Article 16(2)(c) thereof.
23 In those circumstances, according to the settled case-law of the Court, it follows from the need for uniform application of EU law and from the principle of equality that the terms of a provision of EU law which makes no express reference to the law of the Member States for the purpose of determining its meaning and scope must normally be given an autonomous and uniform interpretation throughout the European Union; that interpretation must take into account not only its wording but also its context and the objective pursued by the legislation in question (judgment of 2 June 2022, T.N. and N.N.(Declaration concerning the waiver of succession), C‑617/20, EU:C:2022:426, paragraph 35 and the case-law cited).
24 As regards, first of all, the wording of the first sentence of Article 16(2)(c) of Directive 2009/28, by referring to installations ‘using’ renewable energy sources, that wording does not, in itself, make it possible to determine whether that provision refers only to installations producing exclusively from renewable energy sources or whether it also applies to those only partly using such energy sources for that purpose.
25 Furthermore, the second sentence of that same provision, which refers to measures to be taken in order to minimise the curtailment of electricity produced from renewable energy sources, appears, given the use of the verb ‘to minimise’, to assume that priority access should also be granted to installations only partly using renewable energy sources. To not include such installations would have the effect of excluding from priority access a - potentially significant - proportion of ‘green’ electricity.
26 Next, as regards the context of which that provision forms part, Article 2(c) of Directive 2001/77 defined ‘electricity produced from renewable energy sources’ as ‘electricity produced by plants using only renewable energy sources, as well as the proportion of electricity produced from renewable energy sources in hybrid plants also using conventional energy sources’.
27 Directive 2009/28, which replaced Directive 2001/77 and was in force at the time of the facts in the main proceedings, did not reproduce that definition. In Article 2(a), that directive defines ‘energy from renewable sources’ as ‘energy from renewable non-fossil sources’ and goes on to specify which renewable sources come within that definition. Consequently, as pointed out by 50 Hertz Transmission, the classification as ‘electricity produced from renewable energy sources’ no longer depends on the type of installation in which the electricity was produced, but only on the energy sources used by those installations to produce electricity.
28 Lastly, concerning the objectives pursued by Directive 2009/28, as is apparent from Article 1 thereof, the purpose of that directive is to establish a common framework for the promotion of energy from renewable sources by setting, inter alia, mandatory national targets for the overall share of energy from renewable sources in gross final consumption of energy.
29 In addition, it is apparent from recital 60 of that directive that its aim is, through the integration of electricity from renewable energy sources into the spot market, to favour maximum use of electricity from renewable energy sources. Recital 61 of that directive states that the objective of that directive is a sustained increase in the transmission and distribution of electricity produced from renewable energy sources and that, to that end, Member States should take appropriate measures in order to allow greater penetration of electricity from renewable sources.
30 In addition, according to the Court’s case-law, the purpose of guaranteed access to the grid system provided for in Article 16(2)(b) of Directive 2009/28 is to integrate renewable energy sources into the internal market for electricity by ensuring that all electricity produced from renewable energy sources has access to the grids, allowing the use of a maximum amount of electricity produced from renewable energy sources (see, to that effect, judgment of 27 January 2022, Fondul Proprietatea, C‑179/20, EU:C:2022:58, paragraph 62).
31 The objectives of maximum use of electricity produced from renewable energy sources and a sustained increase in the transmission and distribution of electricity produced from renewable energy sources would risk being undermined if an electricity generating installation not exclusively using renewable energy sources were thereby equated with an installation using only conventional energy sources and, consequently, excluded from the priority access provided for in Article 16(2)(c) of Directive 2009/28.
32 Accordingly, the answer to the first question is that Article 16(2)(c) of Directive 2009/28 must be interpreted as meaning that priority access to the electricity grid enjoyed by electricity generating installations using renewable energy sources must be granted not only to installations producing electricity exclusively from renewable energy sources, but also to those producing from both renewable and conventional energy sources.
33 By its second to fifth questions, which it is appropriate to examine together, the referring court asks, in essence, whether Article 16(2)(c) of Directive 2009/28 must be interpreted as meaning that an installation which produces electricity from both renewable and conventional energy sources, in variable proportions, enjoys priority access to the grid solely for the share of electricity produced from renewable energy sources and, if so, what the detailed rules for applying that access priority are.
34 In the present case, the referring court asks more specifically whether an installation such as the one operated by EEW, which produces electricity from a mixture of waste containing a variable proportion of industrial and municipal biodegradable waste, enjoys priority access to the grid solely for electricity produced from that variable proportion.
35 In that regard, it should be noted at the outset that it is apparent from the definitions set out in Article 2(a) and (e) of Directive 2009/28 that, although energy obtained from the recovery of biomass constitutes energy from renewable sources, only the biodegradable fraction of, inter alia, industrial and municipal waste comes within the concept of ‘biomass’ as defined by that directive. Thus, the energy produced by thermal treatment of industrial and municipal waste is, for electricity produced from that biodegradable fraction of that waste and excluding the fraction thereof consisting of conventional waste, considered to be energy from renewable sources.
36 Next, the Court has held, in respect of Article 16(2)(b) of that directive, that although that provision refers to the possibility of establishing ‘guaranteed access’ to the grid for electricity produced from renewable energy sources, that possibility applies only to ‘green’ electricity and that provision cannot therefore serve as a legal basis for national provisions on guaranteed access for installations producing energy from a conventional source (see, to that effect, judgment of 27 January 2022, Fondul Proprietatea, C‑179/20, EU:C:2022:58, paragraph 65). As observed by the Advocate General in point 46 of his Opinion, the principle of priority access to the grid referred to in Article 16(2)(c) of that directive must be interpreted to similar effect.
37 Consequently, an installation for the production of electricity using a mixture of waste of which only a variable proportion consists of industrial and municipal biodegradable waste or, more generally, using a variable proportion of both renewable and conventional energy sources, must be able to enjoy the priority access provided for in Article 16(2)(c) of Directive 2009/28, up to the sole variable proportion of electricity produced from renewable energy sources.
38 Directive 2009/28 does not, however, determine how the proportion of electricity produced from renewable energy sources by an electricity generating installation using both renewable energy sources and conventional sources must be calculated and, more specifically, whether that proportion must attain a minimum threshold in order for the electricity produced to enjoy priority access.
39 Article 16(2)(c) of that directive merely imposes two requirements.
40 In the first place, that provision makes priority of access subject to needs relating to the security of the national electricity system. In that regard, recital 60 of Directive 2009/28 states that requirements relating to the maintenance of the reliability and safety of the grid and to the dispatching may differ according to the characteristics of the national grid and its secure operation.
41 In the second place, Article 16(2)(c) of Directive 2009/28 requires that priority access be managed on the basis of transparent and non-discriminatory criteria. In that regard, recital 11 of that directive emphasises the importance of defining transparent and unambiguous rules for calculating the share of energy from renewable sources and for defining those sources. Furthermore, recital 60 of that directive reiterates, in general terms, the importance of priority access for electricity from renewable energy sources for the integration of renewable energy sources into the internal electricity market and, in particular, the point that such priority access should be reflected in national connection rules by giving connected generators of electricity from renewable energy sources the assurance that they will be able to sell and transmit electricity from renewable energy sources at all times, whenever the source becomes available.
42 It follows that the Member States have a broad discretion when they lay down the detailed rules for implementing the priority access which must be granted to electricity generating installations using renewable energy sources, provided that they comply with the objectives pursued by that directive.
43 The Court has, moreover, held previously that, by the adoption of Directive 2009/28, far from seeking to bring about exhaustive harmonisation of national support schemes for green energy production, the EU legislature based its approach on the finding that Member States apply different support schemes and on the principle that it is important to ensure the proper functioning of those schemes in order to maintain investor confidence and to enable those States to define effective national measures in order to achieve their mandatory national overall targets under the directive (judgment of 4 October 2018, L.E.G.O., C‑242/17, EU:C:2018:804, paragraph 53 and the case-law cited).
44 Consequently, in accordance with settled case-law, it is for the national court, which alone has jurisdiction to assess the facts and interpret the national legislation, to determine whether, in the present case, the requirements of EU law relating to the determination of the detailed arrangements for giving effect to priority access for installations using renewable energy sources are satisfied. Nevertheless, the Court, which is called on to provide answers which will be of use to the national court in the context of a reference for a preliminary ruling, may provide guidance as to the factors to be taken into account by the Member States for the purpose of applying priority access to the grid, on the basis of the documents relating to the main proceedings and the written and oral observations which have been submitted to it, in order to enable the national court to give judgment (see, by analogy, judgment of 22 September 2020, Cali Apartments, C‑724/18 and C‑727/18, EU:C:2020:743, paragraph 78 and the case-law cited).
45 In that regard, the requirement in Article 16(2)(c) of Directive 2009/28 to the effect that priority access to the grid must be determined on the basis of transparent and non-discriminatory criteria entails, as stated by the Advocate General in point 54 of his Opinion, that they must be clear, notified in advance by the Member States and that their application must be foreseeable for all parties concerned.
46 In addition, it is apparent from the oral argument presented at the hearing before the Court that electricity generating installations may, for the purposes of the application of Article 16(2)(c) of Directive 2009/28, be divided into three groups, comprising installations using only renewable energy sources, those using only conventional energy sources and those using a mixture of renewable and conventional energy sources, respectively.
47 It is clear, first, that, subject to the limitations relating to system security and capacity, installations in the first group must always enjoy priority access for all the electricity they produce and that the installations in the second group cannot obtain, on the basis of that provision, any priority access and, second, that the installations in those first two groups must, in principle, be treated equally within the group to which they belong.
48 As regards installations in the third group, however, it should be borne in mind, in the first place, that, as is apparent from paragraph 37 of the present judgment, priority access is granted to them only in respect of the proportion of the electricity produced from renewable energy sources. In the second place, within the third group, installations cannot be treated equally, since the proportion of renewable energy sources used by them is not necessarily the same.
49 The objective pursued by Directive 2009/28 of promoting the use of energy from renewable energy sources would risk being undermined if installations using a large proportion of renewable energy sources systematically enjoyed priority access, to the detriment of other installations which also use renewable energy sources, but to a lesser extent. The fact remains that, in the light of that same objective, the former must be able to be given priority over the latter, although without enjoying systematic priority.
50 It is therefore important that the criteria used to determine the order in which the grid operator will dispatch installations using a mixture of renewable and conventional energy sources reflect the importance of the proportion of renewable energy sources they use.
51 Similarly, it is important that those criteria take account of the special features and technical constraints which characterise the management of installations’ access to the electricity grids. In that regard, MNG Strom stated that the electricity transmission grid operator does not know, in real time, what proportion of biodegradable waste is being used by an electricity generating installation when that operator has to decide on the order in which installations are to be shut down; indeed, the operators of those installations do not know what proportion of energy is being produced from renewable sources at any given time. For its part, 50 Hertz Transmission stated that the decision on priority is an emergency measure taken in virtually a split second and that it has repercussions for downstream operators, as a result of which priority criteria must make it possible for the grid operator to be given specific guidance.
52 It should be added that the nature of electricity is such that, once it has been allowed into the transmission or distribution system, it is difficult to determine its origin and in particular the source of energy from which it was produced (judgment of 1 July 2014, Ålands Vindkraft, C‑573/12, EU:C:2014:2037, paragraph 87). Similarly, when the transmission grid operator dispatches an electricity generating installation which uses both renewable and conventional energy sources, it is equally difficult to identify specifically the proportion of the electricity produced by that installation from renewable energy sources. Those technical circumstances entail a certain amount of uncertainty, with the result that it cannot be ruled out that part of the electricity declared to have been produced from renewable energy sources was not entirely so at that precise time.
53 The objective which Directive 2009/28 seeks to achieve of maximising grid access for electricity produced from renewable energy sources does not require that, at the precise time when the grid operator dispatches an electricity generating installation using an energy mix, that operator must be aware of the exact proportion of that type of electricity in the total quantity of energy supplied by that installation.
54 It is sufficient in that regard that the implementation of the criteria adopted by the competent national authorities allows, over a sufficiently long and representative period of time and in so far as technically feasible, priority access to the grid to be granted to each installation producing electricity from both renewable and conventional energy sources in proportion to the size of the share of renewable energy sources used by that installation.
55 It cannot be ruled out that the competent national authorities may, to that end, take into account a guarantee of origin within the meaning of Article 2(j) of Directive 2009/28, issued, as the case may be, to an electricity producer under Article 15 of that directive, irrespective of the fact that such a guarantee is, as is apparent from, inter alia, paragraph 1 of that provision, issued in order to enable final customers to satisfy themselves as to the exact composition of an energy supplier’s energy mix.
56 Moreover, there is nothing to prevent the competent national authorities, in the exercise of their discretion as to the setting of those criteria, from relying on certain provisions in Article 5(3) of Directive 2009/28, in particular the provision that, in multi-fuel installations using renewable and conventional energy sources, for the purposes of calculating the share of electricity produced from renewable sources, the contribution of each energy source is to be calculated on the basis of its energy content.
57 It follows from all those considerations that the answer to the second to fifth questions is that Article 16(2)(c) of Directive 2009/28 must be interpreted as meaning that an installation which produces electricity from both renewable and conventional energy sources enjoys priority access to the grid solely in respect of the proportion of electricity produced from renewable energy sources. It is for the Member States to establish the detailed rules for applying that priority access, by setting transparent and non-discriminatory criteria which, whilst taking into account requirements relating to the maintenance of reliability and safety of the grid, make it possible to establish an order of priority according to the size of the share of renewable energy sources used by each installation for the production of electricity.
58 Since these proceedings are, for the parties to the main proceedings, a step in the action pending before the referring 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.