1 This request for a preliminary ruling concerns the interpretation of Article 9(3) of Directive 2012/27/EU of the European Parliament and of the Council of 25 October 2012 on energy efficiency, amending Directives 2009/125/EC and 2010/30/EU and repealing Directives 2004/8/EC and 2006/32/EC (OJ 2012 L 315, p. 1), Article 13 of Directive 2006/32/EC of the European Parliament and of the Council of 5 April 2006 on energy end-use efficiency and energy services and repealing Council Directive 93/76/EEC (OJ 2006 L 114, p. 64), and Articles 101, 107 and 169 TFEU.
2 The request has been made in proceedings between ‘EVN Bulgaria Toplofikatsia’ EAD (‘EVN’), a company supplying thermal energy, and OZ, a natural person, concerning an action for payment of bills for the supply of thermal energy for the dwelling owned by OZ in a co-owned building connected to a district heating system.
3 Recitals 8 and 20 of Directive 2012/27 state: ‘(8) On 8 March 2011, the [European] Commission adopted its Communication on an Energy Efficiency Plan 2011. The Communication confirmed that the [European] Union is not on track to achieve its energy efficiency target. This is despite the progress in national energy efficiency policies outlined in the first National Energy Efficiency Action Plans submitted by Member States in fulfilment of the requirements of [Directive 2006/32]. [An] initial analysis of the second Action Plans confirms that the Union is not on track. To remedy that, the Energy Efficiency Plan 2011 spelled out a series of energy efficiency policies and measures covering the full energy chain, including energy generation, transmission and distribution; the leading role of the public sector in energy efficiency; buildings and appliances; industry; and the need to empower final customers to manage their energy consumption. … … (20) An assessment of the possibility of establishing a ‘white certificate’ scheme at Union level has shown that, in the current situation, such a system would create excessive administrative costs and that there is a risk that energy savings would be concentrated in a number of Member States and not introduced across the Union. The objective of such a Union-level scheme could be better achieved, at least at this stage, by means of national energy efficiency obligation schemes for energy utilities or other alternative policy measures that achieve the same amount of energy savings. It is appropriate for the level of ambition of such schemes to be established in a common framework at Union level while providing significant flexibility to Member States to take fully into account the national organisation of market actors, the specific context of the energy sector and final customers’ habits. The common framework should give energy utilities the option of offering energy services to all final customers, not only to those to whom they sell energy. This increases competition in the energy market because energy utilities can differentiate their product by providing complementary energy services. The common framework should allow Member States to include requirements in their national scheme that pursue a social aim, in particular in order to ensure that vulnerable customers have access to the benefits of higher energy efficiency. Member States should determine, on the basis of objective and non-discriminatory criteria, which energy distributors or retail energy sales companies should be obliged to achieve the end-use energy savings target laid down in this Directive. …’
4 Article 1(1) of that directive reads as follows: ‘This Directive establishes a common framework of measures for the promotion of energy efficiency within the Union in order to ensure the achievement of the Union’s 2020 20% headline target on energy efficiency and to pave the way for further energy efficiency improvements beyond that date. It lays down rules designed to remove barriers in the energy market and overcome market failures that impede efficiency in the supply and use of energy, and provides for the establishment of indicative national energy efficiency targets for 2020.’
5 Article 9(1) and (3) of that directive provides: ‘1. Member States shall ensure that, in so far as it is technically possible, financially reasonable and proportionate in relation to the potential energy savings, final customers for electricity, natural gas, district heating, district cooling and domestic hot water are provided with competitively priced individual meters that accurately reflect the final customer’s actual energy consumption and that provide information on actual time of use. Such a competitively priced individual meter shall always be provided when: (a) an existing meter is replaced, unless this is technically impossible or not cost-effective in relation to the estimated potential savings in the long term; (b) a new connection is made in a new building or a building undergoes major renovations, as set out in [Directive 2010/31/EU of the European Parliament and of the Council of 19 May 2010 on the energy performance of buildings (OJ 2010 L 153, p. 13)]. … 3. Where heating and cooling or hot water are supplied to a building from a district heating network or from a central source servicing multiple buildings, a heat or hot water meter shall be installed at the heating exchanger or point of delivery. In multi-apartment and multi-purpose buildings with a central heating/cooling source or supplied from a district heating network or from a central source serving multiple buildings, individual consumption meters shall also be installed by 31 December 2016 to measure the consumption of heat or cooling or hot water for each unit where technically feasible and cost-efficient. Where the use of individual meters is not technically feasible or not cost-efficient, to measure heating, individual heat cost allocators shall be used for measuring heat consumption at each radiator, unless it is shown by the Member State in question that the installation of such heat cost allocators would not be cost-efficient. In those cases, alternative cost-efficient methods of heat consumption measurement may be considered. Where multi-apartment buildings are supplied from district heating or cooling, or where own common heating or cooling systems for such buildings are prevalent, Member States may introduce transparent rules on the allocation of the cost of thermal or hot water consumption in such buildings to ensure transparency and accuracy of accounting for individual consumption. Where appropriate, such rules shall include guidelines on the way to allocate costs for heat and/or hot water that is used as follows: (a) hot water for domestic needs; (b) heat radiated from the building installation and for the purpose of heating the common areas (where staircases and corridors are equipped with radiators); (c) for the purpose of heating apartments.’
6 Article 10 of Directive 2012/27, entitled ‘Billing information’, provides: ‘1. Where final customers do not have smart meters as referred to in [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), and Directive 2009/73/EC of the European Parliament and of the Council of 13 July 2009 concerning common rules for the internal market in natural gas and repealing Directive 2003/55/EC (OJ 2009 L 211, p. 94)], Member States shall ensure, by 31 December 2014, that billing information is accurate and based on actual consumption, in accordance with point 1.1 of Annex VII, for all the sectors covered by this Directive, including energy distributors, distribution system operators and retail energy sales companies, where this is technically possible and economically justified. This obligation may be fulfilled by a system of regular self-reading by the final customers whereby they communicate readings from their meter to the energy supplier. Only when the final customer has not provided a meter reading for a given billing interval shall billing be based on estimated consumption or a flat rate. 2. Meters installed in accordance with Directives [2009/72] and [2009/73] shall enable accurate billing information based on actual consumption. Member States shall ensure that final customers have the possibility of easy access to complementary information on historical consumption allowing detailed self-checks. Complementary information on historical consumption shall include: (a) cumulative data for at least the three previous years or the period since the start of the supply contract if this is shorter. The data shall correspond to the intervals for which frequent billing information has been produced; and (b) detailed data according to the time of use for any day, week, month and year. These data shall be made available to the final customer via the internet or the meter interface for the period of at least the previous 24 months or the period since the start of the supply contract if this is shorter. 3. Independently of whether smart meters have been installed or not, Member States: (a) shall require that, to the extent that information on the energy billing and historical consumption of final customers is available, it be made available, at the request of the final customer, to an energy service provider designated by the final customer; (b) shall ensure that final customers are offered the option of electronic billing information and bills and that they receive, on request, a clear and understandable explanation of how their bill was derived, especially where bills are not based on actual consumption; (c) shall ensure that appropriate information is made available with the bill to provide final customers with a comprehensive account of current energy costs, in accordance with Annex VII; (d) may lay down that, at the request of the final customer, the information contained in these bills shall not be considered to constitute a request for payment. In such cases, Member States shall ensure that suppliers of energy sources offer flexible arrangements for actual payments; (e) shall require that information and estimates for energy costs are provided to consumers on demand in a timely manner and in an easily understandable format enabling consumers to compare deals on a like-for-like basis.’
7 Annex VII of Directive 2012/27, entitled ‘Minimum requirements for billing and billing information based on actual consumption’, provides, in point 1.1.: ‘Billing based on actual consumption In order to enable final customers to regulate their own energy consumption, billing should take place on the basis of actual consumption at least once a year, and billing information should be made available at least quarterly, on request or where the consumers have opted to receive electronic billing or else twice yearly. Gas used only for cooking purposes may be exempted from this requirement.’
8 Under Article 27 of that directive, entitled ‘Amendments and repeals’, Directive 2006/32 was repealed with effect from 5 June 2014, subject to some exceptions.
9 Article 38b(1) of the Zakon za energetikata (Law on Energy) (DV No 107 of 9 December 2003), in the version applicable in the main proceedings (‘Law on Energy’), provides: ‘Energy companies that are parties to the contracts referred to in Article 38a(1) shall provide their energy service consumers with information on: 1. … the prices of maintenance services and other prices for services associated with the authorised activity; … 3. the actual consumption and the value of services provided, in accordance with the agreed reporting frequency. There is no obligation to make additional payments for this service. …’
10 Article 125(3) of the Law on Energy provides: ‘The Minister of Energy shall adopt a regulation setting out the detailed rules and technical conditions relating to heating; the operational management of the heating system; the connection of producers and customers to the heat transmission network [(the “heating network”)]; distribution; and the termination and suspension of the heat supply. …’
11 Article 139(1) of that law is worded as follows: ‘The consumption of thermal energy in a co-owned building shall be allocated on the basis of a consumption allocation system. …’
12 Under Article 140(1) of that law: ‘In the case of a co-owned building, thermal energy consumption shall be allocated by: … 2. devices for the allocation of thermal energy consumption, namely individual heat cost allocators meeting the standards in force in the country or individual thermal meters; 3. devices for the allocation of domestic hot water consumption, namely a common water meter for the domestic hot water supply and individual meters for hot water distributed to all branches of the building installation to supply hot water to consumers’ properties. …’
13 Article 140a of that law provides: ‘The total amount of thermal energy consumed in a co-owned building connected to a subscriber substation or to an independent branch thereof shall be divided between hot water and heating.’
14 Article 141 of the Law on Energy states: ‘(1) The thermal energy for hot water in a co-owned building shall be determined by: 1. the amount of water consumed in the building for domestic hot water, as recorded by the common water meter; 2. the cost per cubic metre of thermal energy required to heat the amount referred to in point 1, which is determined under the conditions and in accordance with the detailed rules set out in the regulation referred to in Article 125(3). (2) The thermal energy referred to in paragraph 1 shall be allocated among customers under the conditions and in accordance with the detailed rules laid down in the regulation referred to in Article 125(3).’
15 Under Article 142 of that law: ‘(1) The thermal energy designated for heating a co-owned building is the difference between the total amount of thermal energy designated for distribution within the building and the amount designated for hot water, determined in accordance with Article 141(1). (2) The thermal energy designated for heating a co-owned building is subdivided into heat emitted by the building installation, thermal energy designated for heating the communal areas and thermal energy designated for heating individual properties.’
16 Article 38 of Naredba za toplosnabdyavaneto No 16-334 (Regulation No 16-334 on district heating) of 6 April 2007, in the version applicable to the dispute in the main proceedings (‘the Regulation on district heating’), provides: ‘The producer, heat transmission company or supplier shall supply customers with thermal energy in accordance with the following conditions: 1. the units of owners or holders of rights in rem must be connected to the thermal energy transmission distribution network; 2. a contract for the sale of thermal energy shall be concluded between the thermal energy transmission company and customers in accordance with the general terms and conditions; 3. thermal energy consumers must pay any monthly instalments due for thermal energy within the specified time limit.’
17 Article 52(1) and (2) of the Regulation on district heating provides: ‘(1) Thermal energy consumption is allocated between consumers in co-owned buildings by [thermal meters], as follows: 1. individual thermal energy allocators installed on all heat emitters and/or individual heat meters for the properties, complying with the standards and regulations in force in the country; 2. a common cold water meter placed upstream of the boiler for the supply of hot water and individual meters for hot water distributed to all branches of the building installation for the supply of hot water to consumers’ properties; … (2) The devices referred to in paragraph 1 shall contribute to determining the portion of thermal energy consumed by the various consumers in co-owned buildings, downstream [of the heating system]. … …’
18 Article 57 of that regulation provides: ‘(1) Where the amount of thermal energy is measured by [thermal meters] installed beyond the property boundary, the recorded amounts shall be adjusted to account for thermal energy technology costs relating to the section between the [heat meters] and the property boundary. (2) The infrastructure’s thermal energy technology costs shall be determined in accordance with Section IV. (3) The provision referred to in paragraph 1 also concerns subscriber substations in co-owned buildings and buildings with a single owner. …’
19 Paragraph 1 of the supplementary provisions to that regulation contains the following definitions: ‘1. An “algorithm” is a set of rules (formulas) that determine the sequence of computational operations, the application of which leads to the solution of a given problem. … 2a. The “actual installed capacity of a heating installation” is the sum of the installed capacity of the heating emitters in all properties in the co-owned building. 3. A “building installation” or “internal installation” comprises the core vertical and horizontal distribution lines to heat emitters, as well as the equipment used to distribute and supply thermal energy from the subscriber substation to customers’ properties. Where more than one building is connected to a subscriber substation, each connecting heat pipe shall be considered part of the relevant building’s installation. … 8. The “maximum specific cost of the building” is the maximum amount of thermal energy emitted by one kilowatt of installed capacity from a heat emitter in the building, given the building installation’s corresponding operating mode. … 13a. The “projected capacity of the heating installation” is the capacity of the internal heating installation, as specified in the property investment plan. …’
20 The transitional and final provisions of that regulation contain paragraph 2, which is worded as follows: ‘(1) The owners and/or holders of a right in rem relating to the use of a property in a co-owned building shall be required to: 1. install devices for allocating consumption on sealed heat emitters located within their property; 2. install hot water meters on all branches connecting their property to the building installation for the supply of hot water for domestic use. …’
21 The Regulation on district heating includes an annex entitled ‘Methodology for the allocation of thermal energy consumption in co-owned buildings’ (‘the methodology’), point 1 of which provides: ‘The amount of thermal energy that must be allocated is the amount of thermal energy measured by the heat meter in the subscriber station, adjusted for technology costs based on the property boundary, as well as for the amount of thermal energy required to supplement the building installation in cases involving the use of a heat transfer medium from the heating network.’
22 According to point 2 of the methodology: ‘The thermal energy measured by a heat meter in a subscriber substation of a co-owned building for a given metering period shall be the sum of the energy consumed for heating, the energy consumed for the supply of hot water for domestic use … and the thermal energy technology costs in the subscriber substation.’
23 Point 6 of the methodology states that the amount of thermal energy consumed for heating is the difference between the energy as defined in point 1 of the methodology and the amount of thermal energy for the supply of hot water for domestic use.
24 Point 6.1 of the methodology provides: ‘The amount of thermal energy consumed for heating purposes shall include the amounts of thermal energy emitted by the building installation, by the heat emitters in the common parts and by the heat emitters in the individual property.’
25 Under point 6.1.1 of the methodology, the amount of thermal energy emitted by the building installation depends on the type and thermophysical characteristics of the building and the heating installation. The energy supplier determines the allocation of consumption in accordance with the mathematical formula in that point.
26 Point 6.1.3 of the methodology is worded as follows: ‘The amount of thermal energy …, expressed in kWh, emitted by the building installation shall be allocated in proportion to the heated volume of the properties according to the floor plan.’
27 EVN, an energy company within the meaning of the Law on Energy, holds a licence for the generation and transmission of thermal energy on the basis of which it supplies heating and hot water, inter alia, to co-owned buildings.
28 OZ is the owner of a property in a co-owned building which is connected to district heating for which EVN supplies the thermal energy necessary for its operation.
29 In that context, EVN claimed from OZ the unpaid sum of 519 leva (BGN) (approximately EUR 265) in respect of his thermal energy consumption during the period from 1 May 2018 to 31 October 2020. Accordingly, EVN also claimed default interest in the amount of BGN 78.20 (approximately EUR 40), for the period from 3 July 2018 to 5 April 2021.
30 Since OZ did not pay those amounts, EVN brought an action before the Rayonen sad Plovdiv (District Court, Plovdiv, Bulgaria), the referring court, seeking an order that OZ pay them.
31 OZ denies that he is liable for the sums claimed by EVN, on the ground, inter alia, that the mathematical formula referred to in point 6.1.1 of the methodology on the basis of which the allocation of thermal energy consumption between the various co-owners is calculated is contrary to EU law. In addition, OZ claims that there is no written contract for the supply of energy, that the amount claimed by EVN does not correspond to actual consumption, that the meters are defective, that the subscriber substation, that is to say the service room of the building from which heating and hot water is supplied in the various parts of the building, is not in good condition, and that there is no regular accounting for energy consumption.
32 Following the expert report drawn up in the main proceedings, which is not disputed by the parties, it was found that the thermal meters used met the requirements of the Regulation on district heating, but also that there were certain irregularities in the heating installation concerned, with the result that the data used by the supplier were incorrect.
33 In particular, the expert called into question the calculations for the allocation of thermal energy consumption carried out on the basis of the mathematical formula set out in point 6.1.1 of the methodology, in so far as those calculations had the effect that users who did not consume thermal energy were liable for part of the sums payable by users who consumed them but did not pay their bills.
34 In that regard, the referring court has doubts as to the compatibility of the methodology with Article 9(3) of Directive 2012/27. In that context, it points out that the elements of the mathematical formula set out in point 6.1.1 of the methodology are not clear and that, in the light of the factors taken into account in that formula, it is highly likely that the amounts charged to consumers who do not consume thermal energy in their homes are too high. That formula is based on theoretical data contained in the design specifications for heating installations. It does not take into account the conditions in which those installations actually operate, nor does it consider whether those conditions are the same as those envisaged in theory.
35 In those circumstances, the Rayonen sad Plovdiv (District Court, Plovdiv) decided to stay the proceedings and to refer the following questions to the Court of Justice for a preliminary ruling: ‘(1) Do Article 9(3) of Directive [2012/27] and Article 169 TFEU preclude the payment of costs for thermal energy radiated from a building’s installation if staircases and corridors are not equipped with radiators? (2) Do Article 9(3) of Directive [2012/27] and Article 169 TFEU preclude the possibility of a district heating supplier demanding consideration, on the basis of national legislation, for the consumption of heat from a building’s installation, where the quantity of thermal energy is determined according to a formula developed by the administration which - introduces a factor determining the share of the total capacity of the heating system accounted for by the installed capacity of the building’s installation, without it being clear how that factor is established; - is based on an installed capacity of the building’s installation which takes no account of what capacity is actually installed; - takes no account of the temperature of the heat transfer medium in the building’s installation; - assumes that the installation is constantly run at full capacity; - takes no account of the specific mode of operation of the various types of heating system (Tichelmann in the present case) and treats them as identical with regard to mode of operation; - automatically assumes an average temperature of 19 °C for [co-owned buildings]? (3) Do Article 9(3) of Directive 2012/27 and Article 169 TFEU preclude the possibility of a district heating supplier demanding consideration, on the basis of national legislation, for the consumption of heat for hot water, where the quantity of thermal energy is determined according to a formula developed by the administration which takes no account of the temperature to which the water is to be heated and supplied to subscribers or of the thermal energy required to heat it, does not take into account how many cubic metres of hot water the subscribers have consumed, and is applied in such a way that the quantity of water calculated for the winter heating period is always double the quantity calculated in summer? (4) Do Article 13 of Directive [2006/32], Article 9(3) of Directive 2012/27 and Article 169 TFEU preclude the possibility of a district heating supplier demanding consideration, on the basis of national legislation, for the consumption of heat from the installation of a [co-owned building] in proportion to the heatable volume of the apartments according to the floor plan, without taking into account the [amount] of thermal energy actually emitted in line with the technical capacity of the heating systems in the respective apartments? For the purpose of answering that question, is it relevant that, under national legislation, the thermal energy of a building’s installation is a component in the algorithm for calculating the final amount to be paid by users for the total heat (the sum of the amounts for thermal energy emitted from the building’s installation, for heating and for hot water), whereby the amount to be paid for heating an apartment is derived from the difference between the total thermal energy (minuend) and the sum of the thermal energy from the installation, the thermal energy emitted by the radiators in the common parts of the building and the thermal energy for hot water (subtrahend)? (5) Does national legislation under which consumers pay for the supply of thermal energy emitted from a building’s installation in proportion to the heatable volume of the apartments according to the floor plan, without consideration of the amount of heat actually emitted to the individual apartments, infringe the prohibition of abuse of a dominant position under Article 101 TFEU and the prohibition on granting unlawful State aid under Article 107 TFEU[?]’
36 The Commission disputes the admissibility of the questions referred for a preliminary ruling in so far as they concern the interpretation of Articles 101, 107 and 169 TFEU.
37 It claims that the request for a preliminary ruling does not contain any information making it possible to establish a link between the subject matter of the dispute in the main proceedings and Articles 101, 107 and 169 TFEU, or the factual and legal material which would enable the Court to provide an answer which will be of use to the referring court in order to resolve the dispute before it.
38 In addition, as regards the requested interpretation of Article 169 TFEU, the Commission submits that, since that provision relates to an area which is a matter of EU competence, its interpretation should not affect the assessment of measures taken by Member States. In that regard, Directive 2012/27 provides for minimum harmonisation and therefore does not prevent Member States from adopting more stringent measures in order to ensure increased consumer protection.
39 In that regard, it must be recalled that the procedure provided for by Article 267 TFEU is an instrument for cooperation between the Court and the national courts by means of which the Court provides national courts with the criteria of interpretation of EU law which they need in order to decide the disputes before them. In the context of that cooperation, it is for the national court before which the dispute has been brought, which alone has direct knowledge of the facts giving rise to the dispute and must assume responsibility for the subsequent judicial decision, to determine both the need for a preliminary ruling in order to enable it to deliver judgment and the relevance of the questions which it submits to the Court. Consequently, where the questions submitted by the national court concern the interpretation of EU law, the Court is, in principle, bound to give a ruling (judgments of 29 November 1978, Redmond, 83/78, EU:C:1978:214, paragraph 25, and of 4 October 2024, Biohemp Concept, C‑793/22, EU:C:2024:837, paragraph 26 and the case-law cited).
40 However, the Court cannot rule on a question referred for a preliminary ruling where it is quite obvious that the interpretation of a rule of EU law that is sought by a national court bears no relation to the actual facts or purpose of the dispute before that national court, where the problem is hypothetical, or where the Court does not have before it the factual or legal material necessary to give a useful answer to the questions submitted to it (judgments of 13 July 2000, Idéal tourisme, C‑36/99, EU:C:2000:405, paragraph 20, and of 4 October 2024, Biohemp Concept, C‑793/22, EU:C:2024:837, paragraph 27 and the case-law cited).
41 In that regard, Article 94 of the Rules of Procedure of the Court of Justice requires every request for a preliminary ruling to contain ‘a summary of the subject matter of the dispute and the relevant findings of fact as determined by the referring court or tribunal, or, at least, an account of the facts on which the questions are based’, ‘the tenor of any national provisions applicable in the case and, where appropriate, the relevant national case-law’, and ‘a statement of the reasons which prompted the referring court or tribunal to inquire about the interpretation or validity of certain provisions of European Union law, and the relationship between those provisions and the national legislation applicable to the main proceedings’.
42 In the present case, the request for a preliminary ruling does not contain any element capable of establishing a connection between the applicable national legislation at issue in the main proceedings and the provisions of the FEU Treaty of which interpretation is sought.
43 Accordingly, that request does not set out the facts enabling the Court to understand how the resolution of the dispute in the main proceedings would require an interpretation of Articles 101, 107 and 169 TFEU or the reasons why the referring court considers that such an interpretation is necessary for that purpose.
44 In those circumstances, it must be held that the fifth question, relating to the interpretation of Articles 101 and 107 TFEU, is inadmissible, as are the first to fourth questions, in so far as they concern the interpretation of Article 169 TFEU.
45 By its first to fourth questions, which it is appropriate to examine together, the referring court asks, in essence, whether Article 9(3) of Directive 2012/27 must be interpreted as precluding national legislation under which the owner of an apartment in a co-owned building is required to pay, first, the costs passed on to him or her in respect of the thermal energy emitted by all the pipes and installations for the distribution and supply of thermal energy within the building, including where the common parts of the building are not equipped with radiators, whereas those costs are not determined on the basis of actual, individualised consumption, but are aggregated and then allocated between the co-owners in proportion to the heated volume of their apartment, and, second, the costs passed on to that owner in respect of his or her individual consumption of thermal energy for heating his or her apartment and domestic hot water, even though those costs are not determined on the basis of actual, individualised consumption, but on a mathematical formula based on unclear or unsubstantiated parameters.
46 As a preliminary point, it should be noted that, by its fourth question, the referring court asks the Court of Justice to interpret the provisions of Directive 2006/32, more specifically Article 13 thereof, which provides, inter alia, that Member States are to ensure that billing addressed to final customers is based on actual energy consumption, and is presented in clear and understandable terms.
47 In accordance with Article 27(1) of Directive 2012/27, which replaced Directive 2006/32, the latter directive was repealed with effect from 5 June 2014. Similarly, under Article 28(1) of Directive 2012/27, Member States were to bring into force the laws, regulations and administrative provisions necessary to comply with that directive by 5 June 2014 at the latest. That directive does not contain, moreover, any specific provision relating to the temporal application of the provisions of Directive 2006/32, which it replaced.
48 Therefore, since the facts of the dispute in the main proceedings relate to the period from 1 May 2018 to 31 October 2020, it is necessary, in order to provide an answer which will be of use to the referring court, to examine the questions referred for a preliminary ruling in the light of the provisions of Directive 2012/27.
49 First of all, it should be noted that the objective of Directive 2012/27, in accordance with Article 1 thereof, is to promote greater energy efficiency. In that context and as is clear from recital 8 of that directive, the entire energy chain, from the energy producer to the final customer who consumes it, is enlisted to achieve that objective.
50 In that regard, under Article 9(1) of Directive 2012/27, Member States are to ensure that, in so far as it is technically possible, financially reasonable and proportionate, final customers are provided with competitively priced individual meters that accurately reflect the final customer’s actual energy consumption and that provide information on actual time of use.
51 More specifically, in a situation, such as that at issue in the main proceedings, which concerns buildings comprising several apartments connected to a heating network, the second subparagraph of Article 9(3) of that directive provides that individual consumption meters were to be installed by 31 December 2016 to measure the consumption of heat or cooling or hot water for each unit where technically feasible and cost-efficient. That provision further specifies that, where the use of individual meters is not technically feasible or not cost-efficient, to measure heating, individual heat cost allocators are to be used for measuring heat consumption at each radiator, and that Member States may consider alternative cost-efficient methods of measuring heat consumption.
52 As is apparent from Article 1 of Directive 2012/27, read in the light of recital 20 thereof, the Member States enjoy a wide discretion as regards both the choice of appropriate measures to reduce energy consumption and the manner in which they are to be implemented. As such, they may, inter alia, provide for transparent rules on the allocation of costs related to the consumption of thermal energy or hot water in apartment buildings. Rather than opting for precise and exhaustive rules, Member States may also provide for a general framework that leaves discretion to co-ownerships.
53 In that regard, the third subparagraph of Article 9(3) of that directive states that, in a situation such as that at issue in the main proceedings, where multi-apartment buildings are supplied from district heating or cooling, or where own common heating or cooling systems for such buildings are prevalent, Member States may introduce transparent rules on the allocation of the cost of thermal or hot water consumption in such buildings to ensure transparency and accuracy of accounting for individual consumption. Where necessary, those rules may include guidelines on the allocation of costs associated with the consumption, first, of domestic hot water, second, of the heat emitted by the building installation for the purpose of heating common parts, and, third, of heating individual properties.
54 In that context, the Court has already held that, in certain co-owned buildings which are connected to a heating network, such as the building in question in the main proceedings, it is hard to conceive being able completely to distinguish the heating bills individually, in particular in respect of the internal installation, that is to say, all the pipes and installations for the distribution and supply of thermal energy within the building in question, and the common parts. As regards, more specifically the internal installation, it may prove difficult, or even impossible, to determine precisely the amount of heat emitted by that installation in each apartment. That amount comprises not only the heat emitted inside the apartment concerned by the material elements of the internal installation, but also the thermal exchanges between the heated parts and non-heated parts of the building. The apartments in a co-owned building are not thermally independent of each other since heat circulates between the units that are heated and those that are less or are not heated (see, to that effect, judgment of 5 December 2019, EVN Bulgaria Toplofikatsia and Toplofikatsia Sofia, C‑708/17 and C‑725/17, EU:C:2019:1049, paragraphs 85 and 86).
55 In the first place, as regards the question whether Member States may provide that the owner of an apartment in a co-owned building is required to pay costs in respect of the thermal energy emitted by the internal installation, including where the common parts of that installation are not equipped with radiators, it should be noted that Directive 2012/27 does not impose on Member States, where they provide for transparent rules on the allocation of costs relating to the consumption of thermal energy, a condition that the common parts of a co-owned building must be equipped with radiators.
56 Furthermore, as is apparent from the third subparagraph of Article 9(3) of Directive 2012/27 and the case-law cited in paragraph 54 above, in buildings connected to a heating network, such as that at issue in the main proceedings, the heat emitted by the internal installation must be distinguished from the heat emitted in the common parts produced by potential heat emitters, such as radiators in staircases and corridors, in particular because heating pipes cross certain apartments and heat exchanges take place between heated and non-heated rooms. It follows that apartment owners cannot be exempted from the costs associated with the consumption of the thermal energy emitted by the internal installation on the sole ground that the common parts of the building do not have such heat emitters.
57 In the second place, as regards the question whether Article 9(3) of Directive 2012/27 precludes legislation, such as that at issue in the main proceedings, which provides that each owner of an apartment must pay the costs in respect of the thermal energy emitted by the internal heating installation in proportion to the heated volume of the apartments according to the floor plan, the Court has already held, in essence, that national legislation such as that at issue in the main proceedings appears to correspond to the concept of ‘guidelines’, referred to in the third subparagraph of Article 9(3) of that directive, since that legislation provides that the costs relating to thermal consumption are to be allocated between those corresponding to heat emitted by the internal installation, those relating to thermal energy for heating the common parts and those relating to thermal energy for heating individual properties. The Court held that, in view of the discretion afforded to the Member States, Directive 2012/27 does not preclude bills for thermal energy consumption by the internal installation from being calculated for each property owner in the building in proportion to the heated volume of his or her apartment (see, to that effect, judgment of 5 December 2019, EVN Bulgaria Toplofikatsia and Toplofikatsia Sofia, C‑708/17 and C‑725/17, EU:C:2019:1049, paragraphs 90 to 92).
58 In the third place, as regards the mathematical formula on the basis of which the costs associated with the consumption of thermal energy in co-owned buildings are calculated, it must be held that Article 9 of Directive 2012/27 does not set out the requirements that must be met by such a formula.
59 However, in accordance with the third subparagraph of Article 9(3) of Directive 2012/27, Member States may introduce rules on the allocation of costs related to thermal or hot water consumption in buildings in order to ensure transparent and accurate accounting for individual consumption.
60 For such accounting to be regarded as transparent and accurate with regard to those costs, it must be carried out both transparently and accurately, so that the final customer is able, first, to know precisely the costs charged to him or her and, second, to take, where appropriate, measures to adapt his or her personal consumption and, therefore, to comply with the objective of Directive 2012/27, namely to promote greater energy efficiency.
61 It follows that the requirement of transparency and accuracy also applies to the mathematical formula, such as that at issue in the main proceedings, on the basis of which those costs are calculated.
62 In the present case, although the mathematical formula referred to in point 6.1.1 of the methodology is based on certain objective data, it is apparent from the file before the Court, subject to the verifications which it is for the referring court to carry out, that it does not take into consideration a number of parameters linked to the actual operation of the heating installation at issue in the main proceedings. In particular, such a formula should take into account the specific characteristics of the building, such as its insulation and that of the heating system, the materials used for that system and any heat loss.
63 Furthermore, according to the expert report drawn up in the context of the dispute in the main proceedings, that formula lacks clarity in that it contains several ambiguities, which could cast doubt on the transparency of the allocation of costs associated with the consumption of thermal energy or hot water within the building concerned.
64 Furthermore, under Article 10(1) of Directive 2012/27, Member States must ensure that billing information is accurate and based on actual consumption, where this is technically possible and economically justified. That provision refers to point 1.1 of Annex VII to that directive, which provides, inter alia, under the heading ‘Billing based on actual consumption’, that, in order to enable final customers to regulate their own energy consumption, billing should take place on the basis of actual consumption at least once a year, and billing information should be made available at least quarterly, on request or where the consumers have opted to receive electronic billing or else twice yearly. It follows that the cost formula should be based on clear and substantiated parameters so that billing reflects accurate information based on actual consumption.
65 In those circumstances and subject to the verifications which it is for the referring court to carry out, it appears that the mathematical formula referred to in point 6.1.1 of the methodology, on the basis of which the costs associated with the consumption of thermal energy in co-owned buildings are calculated, does not allow for transparency and accuracy of accounting for individual consumption, within the meaning of Article 9(3) of Directive 2012/27.
66 In the light of all of the foregoing considerations, the answer to the first to fourth questions is that Article 9(3) of Directive 2012/27 must be interpreted as not precluding national legislation under which the owner of an apartment in a co-owned building is required to pay the costs passed on to him or her in respect of the thermal energy emitted by all the pipes and installations for the distribution and supply of thermal energy within the building, including where staircases and corridors are not equipped with radiators, in proportion to the heated volume of his or her apartment, provided that the rules and parameters on the basis of which the costs passed on to him or her in respect of his or her individual consumption of thermal energy intended for heating his or her apartment and domestic hot water are calculated guarantee transparent and accurate accounting of individual consumption.
67 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.