JUDGMENT NO. 184

YEAR 2025

ITALIAN REPUBLIC

IN THE NAME OF THE ITALIAN PEOPLE

THE CONSTITUTIONAL COURT

composed of:

President: Giovanni AMOROSO;

Judges: Francesco VIGANÒ, Luca ANTONINI, Stefano PETITTI, Angelo BUSCEMA, Emanuela NAVARRETTA, Maria Rosaria SAN GIORGIO, Filippo PATRONI GRIFFI, Marco D’ALBERTI, Antonella SCIARRONE ALIBRANDI, Massimo LUCIANI, Maria Alessandra SANDULLI, Roberto Nicola CASSINELLI, Francesco Saverio MARINI,

has pronounced the following

JUDGMENT

in the constitutional legitimacy proceeding concerning Articles 1, paragraphs 2, 5, 7, 8 and 9, and 3, paragraphs 1, 2, 4 and 5, of the Law of the Sardinia Region of 5 December 2024, no. 20, titled "Urgent measures for the identification of suitable and unsuitable areas and surfaces for the installation and promotion of renewable energy source (RES) plants and for the simplification of authorization procedures”, promoted by the President of the Council of Ministers by recourse notified on 3 February 2025, filed with the Registry on the same date, registered under no. 8 of the 2025 recourse register and published in the Official Gazette of the Republic no. 9, special first series, of 2025.

Having seen the statement of defense of the Autonomous Region of Sardinia, as well as the intervention statements of Ortus Power Resources Italy srl, OPR Sun 11 srl and others, Pacifico Lapislazzuli srl, FRV Italia srl, EF Agri - sarl, Maple Tree Solar srl, DRen Solare 12 srl, Lightsource Renewable Energy Italy SPV 22 srl, DRen Solare 8 srl, DRen Solare 15 srl, ANT srl, EVO srl, Iberdrola Renovables Italia spa, ERG Wind Energy srl, Engie Trexenta srl, Engie Mistral srl, and Rwe Renewables Italia srl;

having heard Judge Rapporteur Angelo Buscema in the public hearing of 7 October 2025;

having heard the attorneys Carlo Comandè for Pacifico Lapislazzuli srl and for the other intervening parties, Claudio Vivani for RWE Renewables Italia srl, the State attorneys Maria Gabriella Mangia and Giorgio Santini for the President of the Council of Ministers, as well as the attorneys Mattia Pani and Floriana Isola for the Autonomous Region of Sardinia;

deliberated in the chambers of council on 8 October 2025.

Facts Considered

1.– The President of the Council of Ministers, represented and defended by the State General Attorney’s Office, raises questions of constitutional legitimacy concerning Articles 1, paragraphs 2, 5, 7, 8 and 9, and 3, paragraphs 1, 2, 4 and 5, of the Law of the Sardinia Region of 5 December 2024, no. 20, titled "Urgent measures for the identification of suitable and unsuitable areas and surfaces for the installation and promotion of renewable energy source (RES) plants and for the simplification of authorization procedures”, with reference to Articles 3, 41, 97, 117, first paragraph, of the Constitution, the latter in relation to the principles expressed by Directive (EU) 2023/2413 of the European Parliament and of the Council of 18 October 2023, amending Directive (EU) 2018/2001, Regulation (EU) 2018/1999 and Directive no. 98/70/EC as regards the promotion of energy from renewable sources and repealing Council Directive (EU) 2015/652; as well as with reference to Article 117, third paragraph, of the Constitution, in relation to Articles 20, 22 and 23 of Legislative Decree of 8 November 2021, no. 199, titled "Implementation of 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” and Articles 1, paragraph 2, 2 and 7 of the Decree of the Minister for the Environment and Energy Security of 21 June 2024, titled "Regulation for the identification of suitable surfaces and areas for the installation of renewable energy source plants”.

The President of the Council of Ministers also alleges the conflict of the regional legislation with Article 10 of Constitutional Law no. 3 of 18 October 2001 (Amendments to Title V of Part Two of the Constitution) and with Articles 3 and 4, letter e), of Constitutional Law no. 3 of 1948 (Special Statute for Sardinia); as well as, finally, the violation of Article 117, second paragraph, letter m), of the Constitution, in relation to Articles 14 to 14-quinquies, 17-bis and 29 of Law no. 241 of 7 August 1990 (New provisions on administrative procedure and the right of access to administrative documents), insofar as they govern the service conference and the tacit approval (silenzio assenso) also among public administrations, and letter s) of the same article, in relation to Articles 21 and 146 of Legislative Decree no. 42 of 22 January 2004 (Code of Cultural Heritage and Landscape, pursuant to Article 10 of Law no. 137 of 6 July 2002), for violation of the exclusive state legislative competence in the matter of protection of landscape assets.

1.1.– With the first ground of recourse, the President of the Council of Ministers contests the constitutional legitimacy of Article 1, paragraph 2, of Regional Law no. 20 of 2024, inasmuch as it limits the scope of application of the said regional law, placing itself in "open violation of the principle of equality under Article 3 of the Constitution, of legal certainty and legitimate expectation, as well as of the freedom of economic initiative under Article 41 of the Constitution.”

This provision, in fact, by referring to administrative proceedings concerning renewable energy source (RES) plants already underway and those concluded favorably, unless there has been an irreversible change in the state of the places, negatively affects legal certainty and legal situations, also considering the subjective assessment arising from the ascertainment of the irreversible nature of the state of the places; it would cause undoubted damage to the operator and, specifically, to the freedom of economic initiative, considering that, pending the completion of procedures for obtaining enabling titles, the operator may have already incurred significant technical and administrative costs. This provision would thus be unreasonable.

Finally, by restricting "also the minimum area suitable” for the installation of plants, pursuant to Article 20, paragraph 8, of Legislative Decree no. 199 of 2021, it would also violate Article 117, first paragraph, of the Constitution, in relation to the EU principles of maximum dissemination of renewable energy sources, and Articles 3 and 4, letter e), of the Special Statute.

1.2.– With the second ground of recourse, the applicant alleges that Article 1, paragraph 5, first sentence, of Regional Law no. 20 of 2024, by introducing an absolute prohibition on the construction of plants located in areas classified as "unsuitable”, as identified in Annexes A, B, C, D and E, as well as in subsequent paragraphs 9 and 11 of the same article, would conflict with Article 117, first and third paragraphs, of the Constitution, in relation, respectively, to the interposed parameters represented by the principles expressed by Directive 2023/2413/EU, and Articles 20, 22 and 23 of Legislative Decree no. 199 of 2021, as well as Articles 1, paragraph 2, 2 and 7, of the Decree of the Minister for the Environment and Energy Security of 21 June 2024, and Articles 3 and 4, letter e), of the Special Statute.

1.3.– The third ground of recourse challenges Article 1, paragraph 5, insofar as it provides, in the second sentence, that the "prohibition of construction shall also apply to RES plants and storage facilities whose authorization and environmental assessment procedure, under regional or state jurisdiction, is underway at the time of entry into force of this Law” and that, in the third and fourth sentences, "[n]o effect may be given to authorization applications that, although submitted before the entry into force of this Law, are contrary to it and prejudice its implementation. Authorization measures and all enabling titles of whatever denomination already issued, concerning plants located in unsuitable areas, are without effect”, it would also violate the principle of legal certainty, which includes among its corollaries the principle of legitimate expectation recognized by Article 3 of the Constitution and the principle of freedom of economic initiative under Article 41 of the Constitution.

1.4.– With the fourth ground of recourse, the applicant also contests paragraph 7 of Article 1 of the Sardinian Regional Law, insofar as it introduces a criterion of "unsuitability” to prevail in the event that a project falls both in suitable areas and in unsuitable areas. This provision would violate Article 117, first paragraph, of the Constitution, as it would conflict with the EU principle of prevailing public interest in the maximum dissemination of renewable energy sources.

The State General Attorney’s Office states that Article 16-septies of Directive 2018/2001/EU, introduced by Article 1, number 7), of Directive 2023/2413/EU, titled "Prevailing public interest”, sets forth a principle applicable within the scope of the authorization procedure, according to which a case-by-case assessment by the administrative authority is required, a principle that would not justify a generalized ex ante prohibition, as provided by the regional legislator with the challenged provision.

1.5.– The President of the Council of Ministers also challenges, with the fifth ground of recourse, Article 1, paragraph 8, of Regional Law no. 20 of 2024, insofar as it establishes that "[r]efurbishment, total reconstruction, and enhancement interventions relating to plants built and operational before the entry into force of this Law, in unsuitable areas, are permitted only if they do not involve an increase in the occupied gross floor area, and, in the case of wind farms, an increase in the total height of the plant, understood as the sum of the heights of the individual wind turbines of the relevant plant, without prejudice to the provisions of the second sentence of paragraph 6, including compliance with Article 109 of the implementing provisions of the Regional Landscape Plan.”

The aforementioned regulation of refurbishment and restructuring interventions (so-called *revamping* and *repowering*), relating to plants already built and operational before the entry into force of the Regional Law in unsuitable areas, would—according to the applicant—conflict with the principle of legal certainty, as it is unclear whether it should apply only to future interventions or also to interventions already authorized as of the date of entry into force of the challenged Regional Law.

The vagueness of the legal provision would lead to the violation of the principles of equality, reasonableness, legal certainty, and legitimate expectation, as well as the freedom of economic initiative under Articles 3 and 41 of the Constitution.

This provision would also conflict with Article 20 of Legislative Decree no. 199 of 2021, which links the concept of "suitable area” not to the possibility of hosting renewable energy source plants, but to access to certain simplification and acceleration measures for administrative procedures, thus violating fundamental principles adopted by the State legislator in the concurrent legislation matter of "national energy production, transport, and distribution”, under Article 117, third paragraph, of the Constitution, and Articles 3 and 4, letter e), of the Special Statute.

1.6.– With the sixth ground of recourse, the applicant also challenges Article 1, paragraph 9, of Regional Law no. 20 of 2024, insofar as it identifies the list of areas unsuitable for the construction of offshore plants. He considers the powers provided for by Articles 3 and 4, letter e), of the Special Statute, as well as Article 117, third paragraph, of the Constitution, to be violated, because the challenged regional provision would conflict with Article 23 (Authorization procedures for offshore plants and identification of suitable areas) of Legislative Decree no. 199 of 2021, which sets forth fundamental principles established by the State in the concurrent legislation matter of "national energy production, transport, and distribution”. According to the applicant’s position, Article 23 of the aforementioned legislative decree, by establishing the methods for identifying suitable areas for offshore plants, would leave no room for regions to intervene with their own law according to procedures different from those envisaged therein.

1.7.– Finally, with the seventh ground of recourse, Article 3, paragraphs 1, 2, 4 and 5, of Regional Law no. 20 of 2024 is challenged, insofar as it introduces simplification and acceleration measures for the promotion of renewable energy source production plants in unsuitable areas. This provision, by outlining an authorization procedure model different from that provided for by state laws, would be affected by various constitutional legitimacy flaws as, by exceeding the powers that Articles 3 and 4, letter e), of the Special Statute recognize to the Autonomous Region of Sardinia, it would violate the exclusive legislative competence of the State in the matters under Article 117, second paragraph, letters m) and s), of the Constitution, in relation to the following interposed parameters.

1.7.1.– The applicant notes that the challenged regional legislation, with the declared aim of facilitating the achievement of energy transition goals, the promotion of renewable sources, and the containment of energy costs while respecting historical-cultural, landscape-environmental, and agricultural production peculiarities, grants municipalities the faculty to submit a preparatory application for the construction of an RES plant or storage facility within an area identified as "unsuitable”. This application, aimed at reaching an agreement with the region (paragraph 1), is submitted by the municipality following a resolution adopted by a qualified majority of the municipal council (or of the municipal councils whose territory is affected, including due to the visual or landscape impact of the RES plant or storage facility) and is preceded by a "public debate”, as well as by the completion of a popular consultation that must conclude with a favorable position on the proposal (paragraph 2).

Once the described phase is completed, the municipality's application is submitted to the competent regional department, which, based on the regulation of the preparatory and "simplified” service conference under Articles 14, paragraph 1, and 14-bis of Law no. 241 of 1990, respectively, convenes the competent subjects within ninety days of receipt of the application to express themselves unanimously regarding the compatibility of the intervention with the presence of unsuitable areas. In this administrative procedure, by express regional provision, the hypotheses of tacit approval (*silenzio assenso*) do not apply (paragraph 4). Following this, the Regional Executive Board resolves on the agreement based on criteria to be subsequently established by the same Board (paragraph 6).

The proponent, upon completion of the agreement through the procedure described above, may subsequently submit an application to the competent subjects for the implementation of the intervention within the authorization regime provided for ordinary areas, using the simplified authorization procedure (PAS) or the single authorization (AU).

The legislation described above, by providing that the aforementioned municipal application is first subject to an opportunity assessment by the municipal council, preceded by a public debate and then by a technical-administrative assessment, through a service conference, would introduce a procedural model different from the instruments of the service conference and tacit approval governed by Articles 14 to 14-quinquies and 17-bis of Law no. 241 of 1990, and therefore would lead to the violation of Article 117, second paragraph, letter m), of the Constitution, which attributes to the State exclusive legislative competence in matters of determination of essential levels of performance concerning civil and social rights that must be guaranteed throughout the national territory.

The declared simplification and acceleration measures would in fact introduce, at the regional level, the exclusive rule of unanimous resolution by the subjects convened in the service conference, called upon to express themselves on the compatibility of the intervention with respect to unsuitable areas, as well as the inoperability of tacit approval within the service conference itself. The challenged regional procedures would therefore represent derogations from the ordinary functioning of the service conference and tacit approval, provided for by the aforementioned state legislation on administrative procedure.

The applicant notes in this regard that, pursuant to Article 29, paragraph 2-ter, of Law no. 241 of 1990, the provisions of this Law concerning the submission of applications, notifications, and communications, certified commencement of activity notification, and tacit approval and service conference fall under the essential levels of performance referred to in Article 117, second paragraph, letter m), of the Constitution, "save the possibility of identifying, through agreements in the context of the Unified Conference referred to in Article 8 of Legislative Decree no. 281 of 28 August 1997, and subsequent amendments, further cases in which these provisions do not apply”; paragraph 2-quater of the same article further provides that regions and local authorities, in regulating administrative procedures of their competence, "may not establish guarantees lower than those ensured to private parties by the provisions relating to the essential levels of performance referred to in paragraphs 2-bis and 2-ter, but may provide for further levels of protection”; finally, according to the President of the Council of Ministers, the subsequent paragraph 2-quinquies establishes that even special-statute regions and autonomous provinces of Trento and Bolzano "shall adapt their legislation to the provisions of this Article, according to their respective statutes and implementing provisions.”

According to the State General Attorney’s Office, the Sardinian Regional Law provides a lower level of protection than that guaranteed by state legislation, by exclusively providing for the criterion of unanimity for the adoption of the decision regarding the compatibility of the intervention within an area identified as unsuitable, as opposed to state legislation which also allows for the adoption of a conference determination based on prevailing positions. Therefore, the applicant deduces the unconstitutionality of Article 3, paragraphs 1, 2, 4 and 5, of Regional Law no. 20 of 2024, for violation of Article 117, second paragraph, letter m), of the Constitution, "in relation to the cited interposed parameters” (judgments of this Court no. 9 of 2019 and no. 246 of 2018 are cited).

1.7.2.– The challenged Article 3, by violating the aforementioned statutory powers under Articles 3 and 4, letter e), of the Special Statute, also encroaches upon the exclusive legislative competence of the State in the matters under Article 117, second paragraph, letter s), of the Constitution, in relation to the interposed parameters under Articles 21 and 146 of Legislative Decree no. 42 of 2004.

The State General Attorney’s Office highlights that, according to constant constitutional jurisprudence, the preservation of environmental and landscape assets falls, under Article 117, second paragraph, letter s), of the Constitution, under the exclusive care of the State (judgments no. 160 of 2021, no. 178 and no. 172 of 2018 and no. 103 of 2017 are cited). With specific reference to the procedure for issuing landscape authorization, constitutional jurisprudence is also recalled according to which regional legislation cannot provide for a different procedure from that dictated by state law, because regions are not allowed to introduce derogations to environmental protection instruments that establish uniform discipline, valid throughout the national territory, which includes landscape authorization (judgments no. 248 of 2022, no. 160 and no. 74 of 2021, no. 189 of 2016, no. 238 of 2013, no. 235 of 2011, no. 101 of 2010 and no. 232 of 2008).

According to the applicant, the provision in question, by allowing the construction of an RES plant within unsuitable areas following a political agreement between territorial bodies, even in areas subject to cultural or landscape protection, would completely divest the competent Superintendency's authorization procedure, thus harming state legislation serving as a safeguard for cultural and landscape assets.

2.– The Autonomous Region of Sardinia has filed a statement of defense, challenging the admissibility and, alternatively, the merits of the recourse.

2.1.– Firstly, the respondent challenges the admissibility of the questions concerning the provisions of Article 1, paragraphs 2, 5, 7, 8 and 9, of the regional law with reference to Articles 97 and 117, second paragraph, letter s), of the Constitution, due to the lack of reasoning. The violation of these parameters is assertively alleged only in the heading of the relevant ground of recourse, without any indication of the reasons why the challenged regional provisions would conflict with them.

2.2.– With regard to the questions raised concerning the principle of legitimate expectation (Article 1, paragraphs 2 and 5), the Autonomous Region of Sardinia maintains they are unfounded.

The respondent assumes that the provisions challenged on this aspect apply the general principle *tempus regit actum*, according to which *ius superveniens* affects the phases of the procedure that have not yet been concluded. Therefore, in the event that an authorization procedure relating to a project located in an area subsequently classified as unsuitable by new legislation is still underway, the new regulation must necessarily apply, as it is the regulation in force during the course of the procedure.

The principle would also apply, according to the regional defense, to already concluded procedures. It would be necessary, in fact, to consider that the procedure concerning the installation, construction, and operation of renewable energy source plants is structured in various phases, one of which is the one culminating in authorization: a phase that, however, does not exhaust the procedure. This would be followed by the phases of commencement and completion of works, also preceded by procedures for the acquisition of areas and the construction phase.

Alternatively, even if one were to hold the contrary opinion, the fact that the principle of non-retroactivity of law, under Article 11 of the Preliminary Provisions, is not constitutionally binding, except in criminal matters (Article 25, second paragraph, of the Constitution), would be relevant.

In light of constitutional jurisprudence, the legislator, including the regional legislator, would be permitted in this case to intervene unfavorably on previously defined regulatory arrangements, provided there are legal positions that are not adequately consolidated, or following the supervention of public interests, which require legislative interventions directly affecting them negatively, within the limits of the proportionality of the impact with respect to the pursued public interest objectives, in compliance with the principle of reasonableness and to satisfy a supervening public interest such as, in this case, that of ordering a scenario of crowded applications, possibly also with speculative intent, by virtue of the incentives provided.

2.2.1.– The question of constitutional legitimacy of paragraph 2 of Article 1 of Regional Law no. 20 of 2024, based on the assumption that the challenged provision would restrict the minimum area suitable envisaged by Article 20, paragraph 8, of Legislative Decree no. 199 of 2021, would also be inadmissible and, in any case, unfounded.

The question would be inadmissible because the President of the Council of Ministers should also have challenged the subsequent paragraph 6 of the same Article 1, which explicitly provides for the identification of suitable areas.

In any case, according to the regional defense, the question would be unfounded, because Article 20, paragraph 8, of Legislative Decree no. 199 of 2021 does not contain any immutable minimum. The state provision lists, in fact, a series of areas that are considered suitable pending their concrete identification by the regions according to the criteria currently indicated by the Decree of 21 June 2024: thus, the list in the national provision would only be valid until the adoption of regional laws.

2.3.– Likewise inadmissible and unfounded would be the questions of constitutional legitimacy of Article 1, paragraph 5, of Regional Law no. 20 of 2024.

2.3.1.– The inadmissibility would depend on the generality of the recourse and the erroneous reconstruction of the challenged regional legislation.

The regional defense asserts that the applicant has not demonstrated how the challenged regional legislation prevents the achievement of the objectives established by EU legislation, moreover "in the absence of express challenge of the Annexes.”

Also inadmissible would be the claim aiming to assert a conflict with Article 16-septies of Directive 2018/2001/EU, introduced by Article 1, number 7), of Directive 2023/2413/EU, cited only in the heading and not developed in the arguments supporting this specific challenge.

2.3.2.– The challenges would in any case be unfounded because the Autonomous Region, in applying Legislative Decree no. 199 of 2021, taking into account the overall power objective to be reached by 2030 agreed with the State and indicated in Article 2 of the aforementioned Decree of 21 June 2024, would have carried out an investigation based on the specific conditions of the territory and would have regulated the probable future distribution of plants in the areas and surfaces classified as suitable in sufficient number to achieve the aforementioned objective, avoiding the overloading of distribution networks.

The regional defense reports that investigations carried out by regional administrative structures have shown that the "total potential suitable area” would, in any case, guarantee the achievement of the RES energy quotas agreed with the Government. Therefore, the challenged regional legislation intervened to identify and regulate unsuitable areas with the sole intention of preserving the landscape, archaeological, historical-cultural, and environmental heritage of which the Sardinian territory is very rich, without however completely excluding the possibility of installing RES plants in unsuitable areas and surfaces.

The legislation in question, as it is therefore aimed at the protection of the landscape, would have been adopted in compliance with the legislative competence of the Region in matters of building and urban planning, provided for by Article 3, letter f), of the Special Statute, which also includes the landscape.

The regional defense concludes by noting, moreover, that in the areas identified as suitable (Article 1, paragraph 6, and Annex F to Regional Law no. 20 of 2024), as well as in those abstractly unsuitable, the construction of renewable energy plants is always permitted if aimed at self-consumption or serving an energy community.

2.4.– The question of constitutional legitimacy of Article 1, paragraph 7, of Regional Law no. 20 of 2024 would also be unfounded, because the applicant allegedly did not consider the entire content of the provision, from which it emerges that, in the case of plants intended for self-consumption, the suitability criterion would prevail.

2.5.– The question concerning Article 1, paragraph 8, according to the regional defense, would be inadmissible due to the generality of the grounds and, in any case, unfounded because the law, unless otherwise specified, should always be understood as applicable *pro futuro* only.

2.6.– The question relating to offshore regional plants (Article 1, paragraph 9, of Regional Law no. 20 of 2024) would also be inadmissible due to the generality and lack of adequate reasoning.

The regional defense then maintains that the President of the Council of Ministers should also have challenged the second sentence of paragraph 2 of Article 1 of the Regional Law no. 20 of 2024, which establishes that the same law also applies "to the territorial sea and the contiguous sea zone, pursuant to the Montego Bay Convention of 10 December 1982, ratified by Law no. 689 of 2 December 1994 (Ratification and execution of the United Nations Convention on the Law of the Sea, with annexes and final act, done at Montego Bay on 10 December 1982, as well as the agreement on the implementation of Part XI of the same convention, with annexes, done at New York on 29 July 1994)”, so that in these sea areas the Region would be competent to identify areas incompatible with the installation of offshore plants.

Furthermore, with regard to such plants, paragraphs 10 and 11 of the same Article 1, concerning the relative connection works to the land, were not challenged.

Moreover, the Autonomous Region of Sardinia observes that, while Article 23 of Legislative Decree no. 199 of 2021, indicated by the applicant as an interposed norm, concerns the identification of suitable areas, the challenged regional provision refers, instead, to unsuitable areas and is inserted into a context in which, almost four years after the entry into force of Legislative Decree no. 199 of 2021, the State has not yet provided for the planning of the areas in question.

The regional defense notes, in fact, that the Maritime Spatial Management Plans, which are supposed to define the suitable sea areas, approved by Decree of the Minister of Infrastructure and Transport of 25 September 2024, no. 237 (Approval of Maritime Spatial Management Plans pursuant to Article 5, paragraph 5 of Legislative Decree no. 201 of 17 October 2016), do not contain any definition of suitable/unsuitable sea areas.

2.7.– Finally, the questions of constitutional legitimacy of Article 3, paragraphs 1, 2, 4 and 5 of Regional Law no. 20 of 2024 would all be inadmissible or unfounded.

The procedure established by the aforementioned article – concerning the submission by the municipality of an application to the Autonomous Region aimed at establishing a preparatory agreement for initiating an authorization procedure for an RES plant, within an area defined as unsuitable – would be inserted into a phase absolutely antecedent to that in which the individual landscape and urban-building authorization procedures are inserted, on which, therefore, the challenged provision would not have any effect.

Moreover, the application aimed at the agreement would follow the procedures of the preparatory service conference, which is completely separate from the decision-making one, governed by Articles 14 et seq. of Law no. 241 of 1990.

The Region would therefore have regulated a simplification tool to examine, in a single context, a plurality of public interests involved in the administrative procedure which would have a "discretionary nature and free form, as the decision to resort to this instrument and the methods for conducting the conference are entirely left to the will of the proceeding administration”, in compliance with what is established by the same Law no. 241 of 1990, which allows regions and local authorities, in regulating administrative procedures of their competence, to provide for further levels of protection (Article 29, paragraphs 2-bis, 2-ter and 2-quater, of Law no. 241 of 1990 are cited).

The questions raised with reference to Article 117, second paragraph, letter s), of the Constitution, in relation to Articles 21 and 146 of Legislative Decree no. 42 of 2004, would also be inadmissible due to the generality of the grounds and in any case unfounded.

3.– Five associations, acting as *amici curiae*, have filed opinions, four of which were filed in due time, in a sense both supportive of and opposing the government’s recourse, admitted by presidential decree of 1 July 2025.

4.– Twenty companies operating in the renewable energy sector have filed applications to intervene in the proceedings, asserting that they hold differentiated legal positions, which would be directly and immediately harmed by the legislation that is the subject of the proceedings.

5.– The President of the Council of Ministers has filed a further memorandum in which he insists on the acceptance of all the questions identified in the recourse, also referring to the constitutional jurisprudence that has intervened in the meantime (Judgment no. 134 of 2025 is mainly cited).

6.– At the public hearing of 7 October 2025, this Court declared the interventions inadmissible by order attached to this judgment.

Considered in Law

1.– With the recourse indicated in the heading (rec. reg. no. 8 of 2025), the President of the Council of Ministers challenges Articles 1, paragraphs 2, 5, 7, 8 and 9, and 3, paragraphs 1, 2, 4 and 5, of Regional Law no. 20 of 2024, with reference to Articles 3, 41, 97, 117, first paragraph, of the Constitution in relation to the principles expressed by Directive 2023/2413/EU; to Article 117, second paragraph, letter m), of the Constitution in relation to Articles 14 to 14-quinquies, 17-bis and 29, of Law no. 241 of 1990, insofar as it governs the service conference and tacit approval (silenzio assenso) also among public administrations; to Article 117, second paragraph, letter s), of the Constitution in relation to Articles 21 and 146 of Legislative Decree no. 42 of 2004; to Article 117, third paragraph, of the Constitution, in relation to Articles 20, 22 and 23 of Legislative Decree no. 199 of 2021 and Articles 1, paragraph 2, 2 and 7 of the Decree of 21 June 2024, as well as, to Article 10 of Constitutional Law no. 3 of 2001 and Articles 3 and 4, letter e), of the Special Statute.

1.1.– With the first ground of recourse, the President of the Council of Ministers alleges the constitutional illegitimacy of Article 1, paragraph 2, of Regional Law no. 20 of 2024, insofar as it provides that the new law applies to the entire regional territory "including the areas and surfaces on which renewable energy source plants under environmental assessment and authorization, under regional or state jurisdiction, or authorized plants that have not resulted in an irreversible change in the state of the places, are located.” According to the applicant, the challenged paragraph places itself in "open violation of the principle of equality under Article 3 of the Constitution, of legal certainty and legitimate expectation, as well as of the freedom of economic initiative under Article 41 of the Constitution,” by negatively affecting administrative authorization procedures already initiated in compliance with the legislation in force at the time, or even already concluded. The same provision, moreover, by restricting also the minimum of "suitable areas” for the installation of RES plants under Article 20, paragraph 8, of Legislative Decree no. 199 of 2021, also violates Article 117, first paragraph, of the Constitution, in relation to the EU principles of maximum dissemination of renewable energy sources and Articles 3 and 4, letter e), of the Special Statute.

1.2.– The second ground of recourse concerns Article 1, paragraph 5, first sentence, of Regional Law no. 20 of 2024, which, by introducing an absolute prohibition on the construction of plants located in areas classified as "unsuitable”, as identified in Annexes A, B, C, D and E, as well as in subsequent paragraphs 9 and 11 of the same article, would conflict with Article 117, first and third paragraphs, of the Constitution, in relation, respectively, to the interposed parameters represented by the principles expressed by Directive 2023/2413/EU, as well as in relation to Articles 20, 22 and 23 of Legislative Decree no. 199 of 2021, Articles 1, paragraph 2, 2 and 7, of the Decree of 21 June 2024, and Articles 3 and 4, letter e), of the Special Statute.

1.3.– Article 1, paragraph 5, is also challenged, with the third ground of recourse, insofar as it provides, in the second sentence, that the "prohibition of construction shall also apply to RES plants and storage facilities whose authorization and environmental assessment procedure, under regional or state jurisdiction, is underway at the time of entry into force of this Law” and establishes, in the third and fourth sentences, that "[n]o effect may be given to authorization applications that, although submitted before the entry into force of this Law, are contrary to it and prejudice its implementation. Authorization measures and all enabling titles of whatever denomination already issued, concerning plants located in unsuitable areas, are without effect”.

These provisions would violate the principle of legal certainty, which includes among its corollaries the protection of legitimate expectation recognized by Article 3 of the Constitution and the principle of freedom of economic initiative under Article 41 of the Constitution.

1.4.– With the fourth ground of recourse, the applicant also contests paragraph 7 of Article 1 of the Sardinian Regional Law, insofar as it introduces a criterion of "unsuitability”, which is to prevail in the event that a project falls partly in suitable areas and partly in unsuitable areas. This provision would violate Article 117, first paragraph, of the Constitution, as it would conflict with the EU principle of prevailing public interest in the maximum dissemination of renewable energy sources, expressed by Article 16-septies of Directive 2018/2001/EU, introduced by Article 1, number 7), of Directive 2023/2413/EU.

1.5.– The President of the Council of Ministers also challenges, with the fifth ground of recourse, Article 1, paragraph 8, of Regional Law no. 20 of 2024, which establishes that "[r]efurbishment, total reconstruction, and enhancement interventions relating to plants built and operational before the entry into force of this Law, in unsuitable areas, are permitted only if they do not involve an increase in the occupied gross floor area, and, in the case of wind farms, an increase in the total height of the plant, understood as the sum of the heights of the individual wind turbines of the relevant plant, without prejudice to the provisions of the second sentence of paragraph 6, including compliance with Article 109 of the implementing provisions of the Regional Landscape Plan.”

This provision, in addition to harming the principle of legitimate expectation under Article 3 of the Constitution, would be vitiated by violation of EU principles transposed by Legislative Decree no. 199 of 2021, specifically Article 20, according to which the qualification of unsuitability should lead to an aggravation of the administrative procedure and not a preclusion of the intervention.

1.6.– The applicant, with the sixth ground of recourse, also challenges Article 1, paragraph 9, of Regional Law no. 20 of 2024, insofar as it identifies unsuitable areas for the construction of offshore plants, considering violated Articles 3 and 4, letter e), of the Special Statute, as well as Article 117, third paragraph, of the Constitution, because the challenged regional provision would conflict with Article 23 (Authorization procedures for offshore plants and identification of suitable areas) of Legislative Decree no. 199 of 2021, which sets forth fundamental principles established by the State in the concurrent legislation matter of "national energy production, transport, and distribution”, in the event that the more favorable clause provided for by Article 10 of Constitutional Law no. 3 of 2001 is deemed applicable.

According to the applicant’s position, Article 23 of the aforementioned legislative decree would grant regions only the competence to identify suitable areas and unsuitable areas on land, but not for offshore plants, the identification of which would be the responsibility of the State, following a participatory process with the regions.

1.7.– Finally, with the seventh ground of recourse, Article 3, paragraphs 1, 2, 4 and 5, of Regional Law no. 20 of 2024 is challenged, insofar as it introduces alleged simplification and acceleration measures for the promotion of renewable energy production plants in unsuitable areas.

These provisions, by outlining an authorization procedure model different from that provided for by state laws, would be affected by various constitutional legitimacy flaws as, by exceeding the powers that Articles 3 and 4, letter e), of the Special Statute recognize to the Autonomous Region of Sardinia, they would violate the exclusive legislative competence of the State in the matters under Article 117, second paragraph, letters m) and s), of the Constitution.

2.– The Autonomous Region of Sardinia raises several inadmissibility objections.

The inadmissibility of the questions concerning paragraphs 2, 8 and 9 of Article 1 challenged is first raised due to the generality and lack of reasoning; more specifically, regarding the challenges to paragraph 2 (applicability of the law to all projects, regardless of the maturity level of the authorization procedure, with the sole limit of irreversible change of the state of the places), they would be inadmissible because the President of the Council of Ministers should also have challenged the subsequent paragraph 6, which expressly identifies the suitable areas. Regarding the challenges to paragraph 8 (limits to the so-called *revamping* and *repowering*), they would be inadmissible due to the generality and indeterminacy of the challenge, and regarding paragraph 9 (unsuitability of offshore areas), the applicant should also have challenged the second sentence of paragraph 2, as well as subsequent paragraphs 10 and 11, concerning the connection works to the land for offshore plants.

The inadmissibility is also alleged due to an erroneous reconstruction of the regulatory framework for the question concerning paragraph 5 of Article 1; furthermore, the question of constitutional legitimacy of paragraph 7 (prevalence of the unsuitability criterion in the event of a project falling into two different areas) would be inadmissible due to an erroneous reconstruction of the regulatory framework.

Finally, the Region also challenges the generality of the reasoning for the question concerning Article 3, paragraphs 1, 2, 4 and 5, of Regional Law no. 20 of 2024, raised with reference to Article 117, second paragraph, letter s), of the Constitution, as the applicant has not clarified how the invasion of state legislative competence materializes, in concrete terms, nor how the alleged violation of Articles 21 and 146 of Legislative Decree no. 42 of 2004, invoked as interposed norms, is realized.

3.– All exceptions must be declared unfounded.

The recourse, in fact, is supported by sufficient arguments and reasoning capable of making the sense of the individual challenges understood.

More precisely, regarding paragraph 2 of Article 1, the applicant complains that the Sardinian legislator set the irreversible change of the state of the places, resulting from the commencement of works for the installation of RES, as the sole limit to the retroactive application of Regional Law no. 20 of 2024. The violation of Article 117, first paragraph, of the Constitution is alleged, in relation to the EU principle of maximum dissemination of RES, transposed into the domestic legal system by Article 20, paragraph 8, of Legislative Decree no. 199 of 2021.

The challenges, therefore, appear sufficiently clear to be addressed on the merits.

Regarding paragraph 5 of the same article, the State alleges that the Autonomous Region of Sardinia, with the challenged provision, imposes the prohibition of installing RES plants in areas identified as unsuitable, thus harming multiple parameters, all identified by the applicant, together with the relevant interposed norms.

In this case too, the challenge appears clear and sufficiently reasoned.

The same can be said for the question of constitutional legitimacy of paragraph 7: the applicant, in fact, complains that the automatic prevalence of the unsuitability criterion in the event that a plant project falls partly in suitable areas and partly in unsuitable areas conflicts with Article 16-septies of Directive 2018/2001/EU, introduced by Article 1, number 7), of Directive 2023/2413/EU – which qualifies the dissemination of renewable energy plants as a prevailing public interest – with consequent violation of Article 117, first paragraph, of the Constitution.

As for paragraph 8, the President of the Council of Ministers clearly deduces the violation of the principles of legitimate expectation and legal certainty because new limits would be introduced to the so-called *revamping* and *repowering* interventions in unsuitable areas, without clarifying whether these new provisions apply only to the future or also to already authorized interventions. The conflict with Article 20 of Legislative Decree no. 199 of 2021 is also alleged, and therefore the violation of Article 117, third paragraph, of the Constitution, because the qualification of suitable area would not affect the possibility of hosting RES plants but exclusively access to simplified administrative procedures.

Finally, the questions concerning Article 3, paragraphs 1, 2, 4 and 5, must also be deemed sufficiently reasoned, since the arguments put forward in their support allow for an adequate identification of the reasons for the complaints.

4.– The inadmissibility of the questions of constitutional legitimacy of Article 1, paragraphs 2, 5, 7, 8 and 9, of Regional Law no. 20 of 2024, promoted with reference to Article 97 of the Constitution, must be noted *ex officio*, due to the absence of this parameter in the resolution proposing the recourse approved by the Presidency of the Council of Ministers at the meeting of 28 January 2025; moreover, the recourse indicates this parameter only in the heading of the first reasoned part, without developing the challenge in the descriptive part.

The same applies to the questions of constitutional legitimacy of Article 1, paragraphs 2, 5, 7, 8 and 9 of Regional Law no. 20 of 2024, promoted with reference to Article 117, second paragraph, letter s), of the Constitution, as alleged by the regional defense itself, because none of the proposed challenges is reasoned with respect to the violation of the exclusive state legislative competence in the matter of "protection of the environment, the ecosystem, and cultural heritage.”

5.– Before proceeding to the merits, it is useful to briefly recall the EU and national legislation on renewable energy source plants.

The energy transition is considered one of the pillars of the European Union's environmental policy and economic development policy.

The strategy for promoting renewable energy sources was initially defined, as far as is relevant here, by 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, repealed by 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, amending and subsequently repealing Directives 2001/77/EC and 2003/30/EC, which provided for further discipline, which was in turn repealed by Directive 2018/21/EU of the European Parliament and of the Council of 11 December 2018 on the promotion of the use of energy from renewable sources. The strategy on renewable sources was then further boosted by Directive 2018/2001/EU, most recently amended, as anticipated several times, by Directive 2023/2413/EU, the implementing decree for which is in the process of approval.

Concurrently, with the Communication of 11 December 2019 ("European Green Deal”), the European Commission outlined a growth strategy aimed at transforming the European Union into a society with an economy that "will be climate-neutral by 2050 and in which economic growth will be decoupled from resource use.”

In this perspective, Regulation (EU) 2021/1119 of the European Parliament and of the Council of 30 June 2021 was enacted, establishing the framework for achieving climate neutrality and amending Regulation (EC) no. 401/2009 and Regulation (EU) 2018/1999 (European Climate Law), the Article 1 of which established the binding objective of climate neutrality in the Union by 2050, as well as, by 2030, the internal reduction of greenhouse gas emissions (net of absorption), identified by Article 4, paragraph 1 (and also by Recital 26), as at least 55 per cent compared to 1990 levels.

More recently, Regulation (EU) 2024/1991 of the European Parliament and of the Council of 24 June 2024 on nature restoration and amending Regulation (EU) 2022/869 was adopted, for the "long-term and lasting recovery of biodiversity and ecosystem resilience in all terrestrial and marine areas [...] through the restoration of degraded ecosystems” (Article 1, paragraph 1, letter a). This Regulation provides for forms of preservation and improvement of various natural habitats.

Regarding the relationship between habitat protection and the construction of "green” plants, Article 6, paragraph 2, of the aforementioned Regulation affirms the principle that, "[i]n specific and duly justified circumstances, Member States may limit the application of paragraph 1” – i.e., the provision that "the planning, construction and operation of renewable energy production plants […] are presumed to be of overriding public interest” – "to certain parts of their territory as well as to certain types of technologies or projects with specific technical characteristics, in accordance with the priorities established in their respective integrated national energy and climate plans pursuant to Regulation (EU) 2018/1999.”

Thus, Regulation (EU) 2024/1991 clarifies that Member States may establish that the construction of certain plants affecting specific parts of their territory is excluded from the presumption of overriding public interest, thereby removing the related *favor*.

To achieve the objectives of combating climate change and using energy from renewable sources set at the European level until 2030, our country initially approved Legislative Decree no. 387 of 29 December 2003 (Implementation of Directive 2001/77/EC relating to the promotion of electricity produced from renewable energy sources in the internal electricity market), subsequently amended by Legislative Decree no. 28 of 3 March 2011 (Implementation of Directive 2009/28/EC on the promotion of the use of energy from renewable sources, amending and subsequently repealing Directives 2001/77/EC and 2003/30/EC).

Article 12 of Legislative Decree no. 387 of 2003 originally provided for a single administrative procedure in which applications for environmental, landscape, and historical-artistic heritage protection converged, through an appropriate decision-making service conference, in view of obtaining a single authorization for the construction and operation of RES plants, also including the set of connection works to the electricity grid.

Over the years, the aforementioned Article 12 has been subject to numerous amendments, primarily by the aforementioned Legislative Decree no. 28 of 2011, aimed at transposing new EU directives and introducing greater acceleration and simplification measures (e.g., the provision of peremptory deadlines, reduction of decision-making terms, introduction of tacit approval mechanisms and forms of digitalization). In summary, four different models could be identified for the installation of RES plants, in relation to the power limit and the type of plant: a) commencement of work notification (CIL); b) certified commencement of work declaration (DILA); c) simplified authorization procedure (PAS); d) single authorization (AU). If RES plants were subject to environmental procedures (EIA or VIA verification), the procedure for issuing the AU was suspended until their conclusion.

More recently, Legislative Decree no. 190 of 25 November 2024, titled "Regulation of administrative regimes for the production of energy from renewable sources, in implementation of Article 26, paragraphs 4 and 5, letter b) and d), of Law no. 118 of 5 August 2022,” the so-called consolidated text on RES administrative regimes, intervened to reorganize the complex discipline of the matter, reducing the number of administrative models to three (free activity, PAS, AU), for each of which a specific annex was prepared, containing the description of the interventions that determine its application.

The regulation on authorization procedures was then supplemented by that contained in specific guidelines, approved by Decree of the Minister of Economic Development of 10 September 2010 (Guidelines for the authorization of plants powered by renewable sources), functional to ensuring the correct landscape integration of RES plants, with particular regard to wind farms, providing that regions could proceed with the indication of areas and sites unsuitable for the installation of specific types of plants. For plants below certain power thresholds, in relation to the different type, the instrument of declaration of commencement of activity (DIA) was also added.

In this context, Legislative Decree no. 199 of 2021 was also inserted – which implemented the delegation attributed to the Government by Article 5 of Law no. 53 of 22 April 2021 (Delegation to the Government for the transposition of European directives and the implementation of other European Union acts – European Delegation Law 2019-2020) – adopted in the exercise of "an interplay of exclusive state legislative powers in the matter of environmental protection” and concurrent powers, in the matter of "national energy production, transport, and distribution”, as well as "in implementation of Directive 2018/2001/EU” (judgment no. 28 of 2025).

The mechanism for identifying suitable areas is governed by Article 20 of Legislative Decree no. 199 of 2021, paragraph 4 of which provides that regions identify "with law the suitable areas” for the installation of RES plants, on which an accelerated and facilitated procedure is provided for the authorization procedures of the plants themselves. Subsequent Article 22, paragraph 1, of the same legislative decree provides, on the one hand, that the competent authority in landscape matters expresses itself with a mandatory, non-binding opinion and, "If the deadline for expressing the opinion has passed without result,” the administration shall nevertheless rule on the authorization application (letter a); on the other hand, that the terms of the single authorization procedures are reduced by one third (letter b).

In implementation of Article 20, paragraph 1, of Legislative Decree no. 199 of 2021, the Decree of 21 June 2024 established the homogeneous principles and criteria for the identification by the regions, through law, of the suitable and unsuitable surfaces and areas for the installation of RES plants (Article 3, paragraph 1).

Finally, it should be noted that Article 20 of Legislative Decree no. 199 of 2021 was repealed by Decree-Law no. 175 of 21 November 2025 (Urgent measures regarding the Transition 5.0 Plan and energy production from renewable sources), currently under conversion, which introduced new legislation on the identification of suitable areas by inserting Article 11-bis (Suitable areas on land) into Legislative Decree no. 190 of 2024.

6.– Having thus briefly reconstructed the essential features of the legislation concerning the aforementioned plants, the examination of the individual questions of constitutional legitimacy can proceed.

6.1.– The first ground of recourse concerns Article 1, paragraph 2, of Regional Law no. 20 of 2024, according to which the new law applies to the entire regional territory "including the areas and surfaces on which renewable energy source plants under environmental assessment and authorization, under regional or state jurisdiction, or authorized plants that have not resulted in an irreversible change in the state of the places, are located.”

According to the applicant, the challenged paragraph 2 violates the principles of equality under Article 3 of the Constitution, of legal certainty and legitimate expectation, as well as of the freedom of economic initiative under Article 41 of the Constitution, by negatively affecting administrative authorization procedures already initiated in compliance with the legislation in force at the time, or even already concluded. Furthermore, this provision, by restricting also the minimum of "suitable areas” under Article 20, paragraph 8, of Legislative Decree no. 199 of 2021, also violates Article 117, first paragraph, of the Constitution, in relation to the EU principles of maximum dissemination of renewable energy sources.

6.1.1.– The question concerning paragraph 2 of Article 1, insofar as it provides that the new regional law also applies to ongoing authorization procedures, raised with reference to Articles 3 and 41 of the Constitution, is unfounded.

It is a settled principle that in complex proceedings structured in a sequence of autonomous phases and acts – such as authorization procedures for the installation of RES plants – the principle *tempus regit actum* evolves into that of *tempus regit actionem*. This means that each phase of the procedure is governed by the law in force at the time each individual act is performed, not by the law in force at the time the overall procedure commenced, i.e., the time of submission of the application.

On this point, administrative jurisprudence has uniformly held that the principle *tempus regit actum*, in the case of procedural activity that is perfected through the performance of logically and functionally sequential acts, requires that the legal discipline that intervenes *medio tempore* regulates the legal situations emerging within the scope of the phases not yet completed at the time of its entry into force (among many, in this sense, Council of State, fourth section, judgments of 14 January 2024, no. 472, as well as, in a similar sense, 13 June 2025, no. 5153).

From this, it is clear, on the one hand, that measures concluded under the previous law cannot be challenged by the subsequent law; and, on the other hand, that where, for example, the environmental assessment process is still ongoing, the procedure must be considered affected by the *medium tempore* change, i.e., after the submission of the application but before the adoption of the relevant measure.

Therefore, the challenged provision, which provides for the applicability of the new discipline also to ongoing procedures, is not only compliant with the settled jurisprudence of the Council of State, but does not violate the parameters invoked by the remitting judge, as a constitutionally protected expectation of the citizen that a granted administrative procedure will necessarily be concluded on the basis of the same discipline, once initiated under a given discipline, must be excluded.

6.1.2.– Regarding, however, the question concerning Article 1, paragraph 2, insofar as it mandates the application of Regional Law no. 20 of 2024 also to already concluded procedures, raised with reference to the principles of legitimate expectation and freedom of economic initiative, as well as Article 117, first paragraph, of the Constitution, in relation to the EU principle of maximum dissemination of renewable energy sources and Articles 3 and 4, letter e), of the Special Statute, it is founded.

The result expected by the Sardinian legislator, in fact, is to nullify and render *tamquam non essent*, with the sole limit of irreversible change of the state of the places, all authorization measures issued for the construction and operation of plants powered by renewable sources, with respect to which sector operators have already taken action.

More generally, as regards the harm to the principle of legitimate expectation, constitutional jurisprudence has consistently reaffirmed that it does not preclude the legislator from adopting provisions that modify the discipline of legal relationships in a manner unfavorable to the interested parties; however, it is necessary that "such provisions do not degenerate into an irrational regulation, frustrating, with regard to substantial situations based on previous laws, the expectation of citizens in legal certainty, understood as a fundamental element of the rule of law” (judgment no. 216 of 2023, as well as similarly, no. 145 of 2022 and no. 54 of 2019).

Legislative provisions of this kind, therefore, are not *per se* incompatible with the structure of powers established by the Constitution. However, "in consideration of the danger of unequal treatment inherent in such provisions, they must be subject to a strict constitutional review, under the profiles of non-arbitrariness and non-unreasonableness of the legislative choice” (judgment no. 134 of 2025).

The challenged regional provision degenerates into an unreasonably restrictive discipline of legitimate expectation, conflicting with the principle of legal certainty, as it leads to the nullification of all authorization measures issued for the construction and operation of plants powered by renewable sources, without this invalidation being justified by technical or scientific reasons ( *ex plurimis*, judgment no. 88 of 2025).

The provision also violates the principle of reasonableness and the freedom of private economic initiative (Articles 3 and 41 of the Constitution), all the more so because operators, once the procedures for obtaining enabling titles have been successfully completed, have normally incurred significant technical and administrative costs.

The challenged provision, by preventing the construction of already authorized plants, is not even consistent with the EU principles of decarbonization and maximum dissemination of energy produced from renewable sources expressed by Directive 2018/2001/EU and Regulation no. 2021/1119/EU, as implemented by Article 20 of Legislative Decree no. 199 of 2021, which impose themselves as limits on the powers under Articles 3 and 4, letter e), of the Special Statute (most recently, in this sense, judgment no. 28 of 2025).

6.2.– The second ground of recourse concerns Article 1, paragraph 5, first sentence, of Regional Law no. 20 of 2024, which introduces an absolute prohibition on the construction of plants located in areas classified as unsuitable.

According to the applicant, this provision would conflict with Article 117, first and third paragraphs, of the Constitution in relation, respectively, to the interposed parameters represented by the repeatedly mentioned principles of maximum dissemination of energy produced from renewable sources expressed by Directive 2023/2413/EU, as well as in relation to Article 20 of Legislative Decree no. 199 of 2021, Articles 1, paragraph 2, 2 and 7, of the Decree of 21 June 2024, and finally, Articles 3 and 4, letter e), of the Special Statute.

The question is founded.

This Court, even recently, has clarified that, in the new context of the fundamental principles of the matter, the power, provided for by Article 20, paragraph 4, of Legislative Decree no. 199 of 2021, to identify suitable areas by regional law, has been granted to the regions also with regard to unsuitable areas, with the clarification, however, that unsuitability can never equate to an absolute and *aprioristic* prohibition (judgment no. 134 of 2025).

This structure is functional to highlighting regional autonomy and, at the same time, is "capable of warding off the risk that regional political bodies, when there are no evident reasons for safeguarding ecosystems and biodiversity, resort to ‘legislative rip-off’ to accommodate the temptation to obstruct plants in their respective territories (according to the effective expression ‘Nimby’: not in my back yard), which would be in clear contrast with the pressing need for the development of renewable energy […] also in the interest of future generations” (judgment no. 216 of 2022) (again judgment no. 134 of 2025 precisely on the issue of RES plants).

The challenged provision, insofar as it provides, in the first sentence, that unsuitability corresponds to the prohibition of installation, is constitutionally illegitimate for violation of Article 117, first paragraph, of the Constitution, in relation to the interposed parameters represented by the aforementioned principles expressed by Directive 2023/2413/EU of the European Parliament and of the Council of 18 October 2023; as well as in relation to Articles 3 and 4, letter e), of the Special Statute.

6.3.– The third ground of recourse concerns Article 1, paragraph 5, second, third, and fourth sentences, of Regional Law no. 20 of 2024, according to which the "prohibition of construction shall also apply to RES plants and storage facilities whose authorization and environmental assessment procedure, under regional or state jurisdiction, is underway at the time of entry into force of this Law”, and "[n]o effect may be given to authorization applications that, although submitted before the entry into force of this Law, are contrary to it and prejudice its implementation. Authorization measures and all enabling titles of whatever denomination already issued, concerning plants located in unsuitable areas, are without effect.”

These provisions, in addition to conflicting with the principle of maximum dissemination of RES plants, would also violate the principle of legal certainty which includes among its corollaries the principle of legitimate expectation recognized by Article 3 of the Constitution, and the principle of freedom of economic initiative under Article 41 of the Constitution.

In this case too, as in the previous one under paragraph 2, the different provisions subject to challenge must be assessed individually.

6.3.1.– The questions concerning the second and third sentences of paragraph 5 of Article 1, insofar as they provide that the prohibition of construction also applies to RES plants and storage facilities whose authorization and environmental assessment procedure, under regional or state jurisdiction, is underway at the time of entry into force of the Law itself, and that "[n]o effect may be given to authorization applications that, although submitted before the entry into force of this Law, are contrary to it and prejudice its implementation”, are founded.

As observed above, at point 6.1.2., the qualification of an area as unsuitable cannot translate into an *aprioristic* prohibition of installation, but rather implies the impossibility of accessing the simplified authorization procedures, provided for by the state legislator in suitable areas to speed up the dissemination of renewable sources (judgment no. 134 of 2025).

The provision that the qualification of unsuitability results in an automatic prohibition of the installation of RES plants constitutes, therefore, a direct violation of the principles of decarbonization and maximum dissemination of energy produced from renewable sources, expressed by the repeatedly mentioned Directive 2023/2413/EU and therefore conflicts with Article 117, first paragraph, of the Constitution, and with Articles 3 and 4, letter e), of the Special Statute.

6.3.2.– The question concerning the fourth sentence of paragraph 5 of Article 1 of the challenged regional law, insofar as it provides that authorization measures and all enabling titles of whatever denomination already issued, concerning plants located in unsuitable areas, are without effect, is founded, not only with reference to the same parameters already identified in the preceding point, but also with reference to Articles 3 and 41 of the Constitution, for violation of the principles of legitimate expectation, legal certainty, and freedom of economic initiative, for the same reasons indicated in point 6.1.2.

6.4.– The fourth ground of recourse concerns paragraph 7 of Article 1 of the Sardinian Regional Law, according to which, in the event that a project falls partly in suitable areas and partly in unsuitable areas, unsuitability prevails.

This provision would violate Article 117, first paragraph, of the Constitution, as it would conflict with the EU principle of prevailing public interest in the maximum dissemination of renewable energy sources, expressed by Article 16-septies of Directive 2018/2001/EU, introduced by Article 1, number 7), of Directive 2023/2413/EU.

6.4.1.– The question is unfounded, within the limits specified below.

This Court, in the already cited judgment no. 134 of 2025, clarified that the qualification of an area as "unsuitable” does not correspond to the prohibition of installation, but rather "is equivalent to indicating an area where the installation of the plant can nevertheless be authorized, albeit on the basis of a suitable investigation and a reinforced justification.”

Article 1, paragraph 2, letter b), of the Decree of 21 June 2024, in fact, defines unsuitable areas as "areas and sites whose characteristics are incompatible with the installation of specific types of plants according to the methods established by paragraph 17 and Annex 3 of the guidelines issued by Decree of the Ministry of Economic Development of 10 September 2010.”

This reference to previous guidelines means – given the aforementioned paragraph 17, which provides for a "specific investigation” – that the final decision regarding the construction of RES plants, in areas indicated as unsuitable, must be taken, in any case, at the end of the individual authorization procedure concerning the specific plant project, within which reasons favoring its construction could still emerge.

In the specific case, the challenged regional provision must be interpreted to mean that the circumstance that a plant also falls within an area declared unsuitable does not represent an absolute impediment to the construction of renewable sources but rather the impossibility of accessing the simplified authorization procedure.

Pursuant to the aforementioned state legislation, in fact, the final decision regarding the construction of RES plants must be taken at the end of the individual authorization procedure concerning the specific plant project. In that context, therefore, the needs for maximum protection of the landscape and protected natural areas that justify the non-simplified authorization procedure must be duly considered. This also allows for evaluating the relationship between the two areas in concrete terms and fully balancing the protection of nature and the protection of the environment through the reduction of polluting energy sources.

Thus interpreted, the challenged provision passes the constitutional legitimacy review.

6.5.– The fifth ground of recourse concerns Article 1, paragraph 8, of Regional Law no. 20 of 2024, according to which "[r]efurbishment, total reconstruction, and enhancement interventions relating to plants built and operational before the entry into force of this Law, in unsuitable areas, are permitted only if they do not involve an increase in the occupied gross floor area, and, in the case of wind farms, an increase in the total height of the plant, understood as the sum of the heights of the individual wind turbines of the relevant plant, without prejudice to the provisions of the second sentence of paragraph 6, including compliance with Article 109 of the implementing provisions of the Regional Landscape Plan.”

The President of the Council of Ministers alleges that the Autonomous Region of Sardinia introduces new legislation on *revamping* and *repowering*, according to which only *revamping* interventions would be permitted, provided that the volumes and heights of the plants are not modified.

In addition to harming the principle of legitimate expectation, the challenged provision would be vitiated by violation of EU principles for the maximum dissemination of RES plants implemented by Article 20 of Legislative Decree no. 199 of 2021, according to which the qualification of unsuitability should lead to an aggravation of the administrative procedure and not a preclusion of the intervention.

6.5.1.– The question is founded.

The regulatory framework at the national level for *revamping* and *repowering* interventions on existing plants (i.e., modernization interventions aimed at greater efficiency and enhancement) – in force at the time the Sardinian Regional Law was approved, i.e., before the entry into force of Legislative Decree no. 190 of 2024 – was structured through the provision of different administrative procedures depending on the (substantial or non-substantial) nature of the variations made.

In addition to what is generally established by Article 20 of Legislative Decree no. 199 of 2021, referred to by the applicant as an interposed norm, Article 5 of Legislative Decree no. 28 of 2011, in its latest wording, established certain criteria for qualifying a variation as "non-substantial”, specifying that this qualification (with the exception of interventions subject to certified commencement of work declaration) did not automatically exclude the need for environmental procedures, and deferred the identification of "substantiality” criteria to a subsequent ministerial decree.

Subsequently, Legislative Decree no. 190 of 2024 modified this system, having provided also for modification interventions (on existing plants or authorized projects) – depending on their consistency – for realization under the "free” regime (Annex A), simplified authorization procedure (Annex B), and single authorization (Annex C).

The challenged regional provision introduces different types of limits to *repowering* and *revamping* activities, linked both to the extension of the affected surfaces and, in fact, to the number of new-generation wind turbines that can be authorized, thus introducing a criterion different from that established by the state legislator, with which it conflicts.

This criterion is extraneous both to the state provisions under Article 20 of Legislative Decree no. 199 of 2021, and to what is established by the Decree of 21 June 2024, which have attributed to the regions the competence to identify suitable and unsuitable areas, not to introduce limiting criteria to the dissemination of RES plants alternative to (and conflicting with) those provided by the state legislator.

The provision must therefore be declared constitutionally illegitimate for violation of Articles 3 and 4, letter e), of the Special Statute and Article 117, first paragraph, of the Constitution, in relation to the EU principle of maximum dissemination of RES plants, with absorption of the other aspects.

6.6.– The sixth ground of challenge concerns Article 1, paragraph 9, of Regional Law no. 20 of 2024, insofar as it identifies unsuitable areas for the construction of offshore plants.

The applicant believes that Articles 3 and 4, letter e), of the Special Statute, as well as Article 117, third paragraph, of the Constitution, are violated, because the challenged provision would conflict with Article 23 of Legislative Decree no. 199 of 2021, which sets forth fundamental principles established by the State in the concurrent legislation matter of "national energy production, transport, and distribution.”

The question is founded.

Article 23, paragraph 1, of Legislative Decree no. 199 of 2021 – before its repeal by Article 15, paragraph 1, and Annex D, letter p), of Legislative Decree no. 190 of 25 November 2024, titled "Regulation of administrative regimes for the production of energy from renewable sources, in implementation of Article 26, paragraphs 4 and 5, letter b) and d), of Law no. 118 of 5 August 2022”, effective from 30 December 2024, pursuant to Article 17, paragraph 1, of the same Legislative Decree no. 190 of 2024 – provided that for offshore plants, the authorization was issued by the Minister for Ecological Transition, in agreement with the Minister of Infrastructure and Sustainable Mobility and after consulting, for aspects related to maritime fishing activities, the Minister for Agricultural, Food and Forestry Policies, within the scope of the measure adopted following the single procedure referred to in subsequent paragraph 4, including the issuance of the maritime state property concession.

The identification of suitable areas for the installation of offshore RES plants is the responsibility of the Minister of Infrastructure and Transport, through the approval of maritime spatial management plans (paragraph 2). Pending the approval of the aforementioned plans, subsequent paragraph 3 provides that the following are considered suitable in any case: disused oil platforms and the area at a distance of 2 nautical miles from each platform; as well as, for wind farms up to 100 MW, ports, subject to any amendment of the port master plan. It is also established, still pending the definition of suitable areas, a prohibition on any moratorium or suspension of deadlines for authorization procedures for applications already submitted (paragraph 5).

Legislative Decree no. 199 of 2021, therefore, does not provide for regional legislative competence to identify suitable areas for offshore sites, nor unsuitable areas.

This is not precluded by the fact that the Decree of 21 June 2024, in the context of the total nominal power for achieving the objectives to be reached by 2030, also refers to offshore plants, providing for specific criteria for the allocation of produced nominal power, where the relative connection works fall within the territory of a region different from that whose coast is closest to the offshore works (Article 2, paragraphs 2 and 4, of the aforementioned Decree).

This legislation, moreover, does not appear to deviate from that recently introduced by Article 2, paragraph 1, letter h), of Decree-Law no. 175 of 2025, under conversion, which inserted Article 11-ter (Suitable sea areas) into Legislative Decree no. 190 of 2024, pursuant to which "areas identified by maritime spatial management plans are considered suitable areas for the realization of interventions relating to offshore renewable energy production plants”; the new legislation is not relevant in the present judgment.

From this, it must be concluded that, in identifying suitable and unsuitable areas with law, regions can only do so with reference to those "on land”, while the identification of suitable offshore sites for the installation of RES plants is the responsibility of the State, through the preparation of maritime spatial management plans, without prejudice to the competence of the Minister for the Environment and Energy Security and the Minister of Infrastructure and Transport for the issuance of the single authorization.

The challenged regional provision is, therefore, constitutionally illegitimate for violation of Article 117, first paragraph, of the Constitution, in relation to the repeatedly cited EU principles as implemented by Article 23 of Legislative Decree no. 199 of 2021, as well as the statutory powers under Articles 3 and 4, letter e), of the Special Statute.

6.7.– The seventh ground of challenge concerns Article 3, paragraphs 1, 2, 4 and 5, of Regional Law no. 20 of 2024, which introduces alleged simplification and acceleration measures for the promotion of renewable energy production plants in unsuitable areas.

These provisions, by outlining an authorization procedure model different from that provided for by state laws, would be affected by various constitutional legitimacy flaws as, by exceeding the powers that Articles 3 and 4, letter e), of the Special Statute recognize to the Autonomous Region of Sardinia, they would violate the exclusive legislative competence of the State in the matters under Article 117, second paragraph, letters m) and s), of the Constitution.

6.7.1.– The questions concerning Article 3, paragraphs 1, 2, 4 and 5, of Regional Law no. 20 of 2024 are founded, with reference to Articles 3 and 4, letter e), of the Special Statute, as well as Article 117, second paragraph, letter s), of the Constitution, in relation to Articles 21 and 146 of Legislative Decree no. 42 of 2004.

The challenged regional legislation provides that, in the case of an unsuitable area, the prohibition of installation provided for by paragraph 5 of Article 1 can be overcome by activating a rather articulated procedure, which begins with an application from the municipality concerned for the installation of RES plants, aimed at reaching an agreement with the Region (paragraph 1). This application is submitted after a resolution by a qualified majority of the municipal council (or of the municipal councils whose territory is affected), and is preceded by a "public debate”, as well as by the completion of a popular consultation that must conclude with a favorable position (paragraph 2). Once the phase described above is completed, the municipality's application is submitted to the competent regional department, which, based on the regulation of the service conference under Articles 14, paragraph 1, and 14-bis of Law no. 241 of 1990, within ninety days of its receipt, convenes the competent subjects to express themselves unanimously regarding the compatibility of the intervention with the presence of unsuitable areas. In this administrative procedure, by express regional provision, the hypotheses of tacit approval (*silenzio assenso*) do not apply (paragraph 4). Following this procedural sequence, the Regional Executive Board resolves on the agreement based on criteria to be subsequently established by the same Board (paragraph 6). The proponent, once the agreement is finalized based on the procedure described above, may subsequently submit an application to the competent subjects for the implementation of the intervention within the authorization regime provided for ordinary areas using the PAS or AU regime.

It should also be recalled that this Court has affirmed that "the preservation of environmental and landscape assets falls, under Article 117, second paragraph, letter s), of the Constitution, under the exclusive care of the State” ( *ex multis*, judgments no. 178 and no. 172 of 2018 and no. 103 of 2017) and that for special-statute regions, like Sardinia, which have exclusive legislative powers in the matter under their statute, the state legislator retains the power to bind these powers with norms classifiable as economic-social reforms ( *ex plurimis*, judgment no. 160 of 2021).

This Court has also repeatedly affirmed that regional legislation cannot provide for a different procedure for landscape authorization than that dictated by state legislation, because regions are not allowed to introduce derogations to state environmental protection instruments, which establish uniform discipline, valid throughout the national territory, within which landscape authorization must be included ( *ex multis*, judgments no. 22 of 2025 and no. 160 of 2021).

The provisions challenged today, instead, allow the approval of interventions in unsuitable areas through the complex procedure provided for by the aforementioned Article 3, even "regardless of the landscape authorization under Article 146 of the Code of Cultural Heritage and Landscape, which is a norm of major economic-social reform that the Autonomous Region of Sardinia must respect (judgment no. 238 of 2013), as adopted within the scope of the State's exclusive competence in the matter of "protection of the environment, the ecosystem, and cultural heritage,” under Article 117, second paragraph, letter s), of the Constitution” (judgment no. 189 of 2016).

Therefore, the provisions in question must be declared constitutionally illegitimate, for violation of Articles 3 and 4, letter e), of the Special Statute and Article 117, second paragraph, letter s), of the Constitution, in relation to Articles 21 and 146 of Legislative Decree no. 42 of 2004.

The further challenges are absorbed.

The declaration of constitutional illegitimacy must be extended consequently, pursuant to Article 27 of Law no. 87 of 11 March 1953 (Provisions on the constitution and functioning of the Constitutional Court), to paragraph 6 of Article 3, which delegates the Regional Executive Board to define the criteria and procedures for the public debate and the methods for involving the interested populations, as well as the criteria for investigation and assessment of applications.

for these reasons

THE CONSTITUTIONAL COURT

1) declares the constitutional illegitimacy of Article 1, paragraph 2, first sentence, of the Law of the Sardinia Region of 5 December 2024, no. 20, titled "Urgent measures for the identification of suitable and unsuitable areas and surfaces for the installation and promotion of renewable energy source (RES) plants and for the simplification of authorization procedures”, limited to the words ", or authorized plants that have not resulted in an irreversible change in the state of the places”;

2) declares the constitutional illegitimacy of Article 1, paragraph 5, first, second, third, and fourth sentences, of Regional Law no. 20 of 2024;

3) declares the constitutional illegitimacy of Article 1, paragraph 8, of Regional Law no. 20 of 2024;

4) declares the constitutional illegitimacy of Article 1, paragraph 9, of Regional Law no. 20 of 2024;

5) declares the constitutional illegitimacy of Article 3, paragraphs 1, 2, 4 and 5, of Regional Law no. 20 of 2024;

6) declares, consequently, pursuant to Article 27 of Law no. 87 of 11 March 1953 (Provisions on the constitution and functioning of the Constitutional Court), the constitutional illegitimacy of Article 3, paragraph 6, of Regional Law no. 20 of 2024;

7) declares inadmissible the questions of constitutional legitimacy of Article 1, paragraphs 2, 5, 7, 8 and 9, of Regional Law no. 20 of 2024, promoted, with reference to Article 97 of the Constitution, by the President of the Council of Ministers with the recourse indicated in the heading;

8) declares inadmissible the questions of constitutional legitimacy of Article 1, paragraphs 2, 5, 7, 8 and 9, promoted, with reference to Article 117, second paragraph, letter s), of the Constitution, by the President of the Council of Ministers with the recourse indicated in the heading;

9) declares unfounded the question of constitutional legitimacy of Article 1, paragraph 2, first sentence, of Regional Law no. 20 of 2024, insofar as it provides that the new regional law also applies to ongoing authorization procedures, promoted, with reference to Articles 3 and 41 of the Constitution, by the President of the Council of Ministers with the recourse indicated in the heading;

10) declares unfounded, within the limits specified in the reasoning, the question of constitutional legitimacy of Article 1, paragraph 7, of Regional Law no. 20 of 2024, promoted, with reference to Article 117, first paragraph, of the Constitution, in relation to Article 16-septies of 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, introduced by Article 1, number 7), of Directive (EU) 2023/2413 of the European Parliament and of the Council of 18 October 2023, amending Directive (EU) 2018/2001, Regulation (EU) 2018/1999 and Directive no. 98/70/EC as regards the promotion of energy from renewable sources and repealing Council Directive (EU) 2015/652, by the President of the Council of Ministers with the recourse indicated in the heading.

Decided in Rome, at the seat of the Constitutional Court, Palazzo della Consulta, on 8 October 2025.

Signed:

Giovanni AMOROSO, President

Angelo BUSCEMA, Rapporteur

Roberto MILANA, Registrar Director

Filed in the Registry on 16 December 2025

 

Annex:

Order read at the hearing of 7 October 2025

ORDER

Having seen the documents relating to the constitutional legitimacy proceeding concerning Articles 1, paragraphs 2, 5, 7, 8 and 9, and 3, paragraphs 1, 2, 4 and 5, of the Law of the Sardinia Region of 5 December 2024, no. 20, titled "Urgent measures for the identification of suitable and unsuitable areas and surfaces for the installation and promotion of renewable energy source (RES) plants and for the simplification of authorization procedures”, promoted by the President of the Council of Ministers by recourse filed on 3 February 2025 (rec. reg. no. 8 of 2025).

Noting that, by acts filed on 17 and 18 March 2025, the companies Ortus Power Resources Italy srl, OPR Sun 8 srl, OPR Sun 11 srl, OPR Sun 17 srl, OPR Sun 30 srl, Pacifico Lapislazzuli srl, FRV Italia srl, EF Agri - società agricola arl, Maple Tree Solar srl, DRen Solare 12 srl, Lightsource Renewable Energy Italy spv 22 srl, DRen Solare 8 srl, DRen Solare 15 srl, ANT srl, EVO srl, Iberdrola Renovables Italia spa, ERG Wind Energy srl, Engie Trexenta srl, Engie Mistral srl, as well as RWE Renewables Italia srl, intervened in the proceedings;

that the aforementioned companies, active in the development, construction, repair, and operation of energy production plants from renewable wind, photovoltaic, and agrivoltaic sources and in the construction of renewable energy storage plants in Italian territory, assert, collectively, to hold a "qualified interest” for the protection of which they would be legitimized to intervene *ad adiuvandum*, noting that the admissibility of the intervention would ensure them the exercise of the right to defense and would be consistent with the principle of equality, considering the possibility, recognized by this Court to subjects holding collective or diffuse interests, of filing *opiniones*.

Considering that this Court has repeatedly affirmed that the proceeding in principal "is carried out exclusively between subjects holding legislative power and does not admit the intervention of subjects who lack it” (*ex plurimis*, order read at the hearing of 9 April 2024, attached to judgment no. 119 of 2024), nor "subjects other than the applicant party and the holder of the legislative power whose exercise is contested, except for the exceptional hypothesis in which the challenged law specifically affects the sphere of constitutional attribution of other regions or autonomous provinces” (order read at the hearing of 8 July 2025, attached to judgment no. 134 of 2025 and order read at the hearing of 14 January 2025, attached to judgment no. 28 of 2025);

that this Court has also excluded that the narrow scope within which intervention is admissible prejudices the right to defense of subjects whose interests may be affected by the outcome of the action proceeding, observing that this "does not arise from a concrete dispute with respect to which the interest of specific subjects can be configured, but rather from the abstract conformity to the Constitution of the challenged law” (order read at the hearing of 9 April 2024 and attached to judgment no. 119 of 2024);

that, therefore, the interventions must be declared inadmissible.

For These Reasons

THE CONSTITUTIONAL COURT

declares inadmissible the interventions in the proceedings by the companies Ortus Power Resources Italy srl, OPR Sun 8 srl, OPR Sun 11 srl, OPR Sun 17 srl, OPR Sun 30 srl, Pacifico Lapislazzuli srl, FRV Italia srl, EF Agri - società agricola arl, Maple Tree Solar srl, DRen Solare 12 srl, Lightsource Renewable Energy Italy spv 22 srl, DRen Solare 8 srl, DRen Solare 15 srl, ANT srl, EVO srl, Iberdrola Renovables Italia spa, ERG Wind Energy srl, Engie Trexenta srl, Engie Mistral srl, as well as RWE Renewables Italia srl.

Signed: Giovanni Amoroso, President