Update review on tax issues relevant to the Energy and Utilities sector – December 2025  

Edited by Energy Team

Tremonti Ambiente: New waiver option available if it cannot be combined with other energy bills

The new simplification law (Law 182/2025) published on December 3rd introduced, in Article 43, a new option for electricity producers from photovoltaic systems who have benefited from the “Tremonti Ambiente” (Article 6, paragraphs 13-19 of Law 388/2000) to continue to benefit from incentive tariffs (III, IV, and V Energy Accounts) without renouncing them according to the procedures set forth in Article 36, paragraph 2, Legislative Decree 124/2019.

The cumulation between the Incentive Tariff and the Tremonti Ambiente was a matter debated until, at the end of 2017, the Gestore dei Servizi Elettrici (GSE) clarified that:

• “Compared to the decrees of 28 July 2005 (I Energy Account) and 19 February 2007 (II Energy Account),it is possible […] to benefit from both the tax relief provided for by the Tremonti environment law and the incentive tariffs recognised by the GSE for the production of electricity, within the limits of 20% of the investment cost […].
• “Article 5 of the Ministerial Decree of 6 August 2010 (III Energy Account) and Articles 5 and 12, respectively, of the Ministerial Decrees of 5 May 2011 (IV Energy Account) and 5 July 2012 (V Energy Account) establish the conditions for cumulation, exhaustively listing the public contributions and benefits excluded from the prohibition on cumulation, not including tax relief for investments”.

Also in light of the above, the legislator introduced a measure to allow holders of “energy accounts” subsequent to the second to waive the Tremonti Ambiente tax credit in order to maintain the right to receive the incentives granted by GSE by returning the tax benefits obtained (Article 36 of Legislative Decree No. 124/2019). The deadline for such option was December 31, 2020, after which it no longer seemed possible to waive the Tremonti Ambiente tax benefit. This is also reflected in the response to this year’s ruling No. 167, in which the Revenue Agency concluded “that there is no other way to waive the Tremonti Ambiente tax benefit, as all the legal deadlines for the return of the related benefits have expired.” (See our newsletter on this point).

In this context, the newly introduced rule allows for the reopening of the terms for waiving the tax relief in order to maintain the right to the energy bill.

More specifically, if the Tremonti Ambiente and energy bills cannot be cumulated, the simplification law makes the maintenance of the latter conditional on the submission of an application to the GSE within 60 days of the law’s entry into force (i.e.,from December 18th), in which the operator accepts the application of:

1. an offset, using the incentive tariffs, of the amount corresponding to the tax benefit enjoyed (i.e., the decrease adjustment resulting from the relief multiplied by the current income tax rate from year to year applicable); please note that the amount in question must be certified by a qualified and independent professional, according to criteria established by the GSE;
2. a 5% reduction in the incentive rates applicable for the entire period of validity of the agreement signed with the GSE.

The request affects all pending proceedings, which will be dismissed subject to the completion of the compensations and reductions described above – or – the payment of any amounts that are not covered by the incentive tariffs.

Within ten days of the new provision coming into force, the GSE is required to publish on its institutional website the application methods of this procedure as well as the categories of professionals authorized to perform the necessary certification.

Constitutional Court: The (first) extraordinary contribution against high utility bills is not unconstitutional

On December 2, the Constitutional Court issued ruling no. 180/2025, which found that the extraordinary contribution provided for by Article 37 of Legislative Decree 21/2022 against the high utilities bill costs is not unconstitutional with regard to the three aspects examined during the proceedings. The contribution under discussion is determined based on parameters arising from the “LIPE” returns and owed by entities operating in the electricity, gas, and oil products sectors within the Italian territory. In short, the contribution was set at 25%, applied to a taxable base consisting of the increase in the balance between active and passive transactions, for the period from October 1, 2021, to April 30, 2022, compared to the same balance for the period from October 1, 2020, to April 30, 2021.

With regard to the constitutional issues examined, the Court’s findings were as follows:

1. non-deductibility of the extraordinary contribution from the IRES taxable base (violation of Articles 3 and 53 of the Constitution): although it is a tax burden that is in principle deductible according to Article 99 of the TUIR, the ruling holds that the non-deductibility “on the one hand, appears not inconsistent with its nature and, on the other hand, it represents a non-unreasonable or disproportionate derogation from the principle of deductibility of the related tax costs from IRES”;
2. expropriatory effects generated by the same levy (in violation of the principles of ability to pay, reasonableness and proportionality of taxation, and protection of property rights set forth in Articles 3, 53, and 42 of the Constitution, as well as contrary to Article 117 of the Constitution and Article 1 of the First Protocol to the ECHR): the Court found that the mechanism for determining this levy—including the absence of a maximum cap—would have produced such marked expropriatory effects as to determine the impact of the taxpayer. However, according to the Court, precisely on the basis of the specific context, this would not be unreasonable;
3. the lack of homogeneity, in relation to newly incorporated companies, of the time periods compared for the purposes of calculating the extraordinary contribution (in violation of Articles 3 and 53 of the Constitution): the Court also considers this challenge by the taxpayer to be not grounded, arguing that “A constitutionally oriented interpretation of Article 37, paragraph 2, of Legislative Decree 21 of 2022, as converted and subsequently amended, therefore requires that, for the purposes of calculating the contribution, the first time period, in the case of newly incorporated companies, runs from the completion of passive transactions aimed at business activity and that, correspondingly, the second time period also be, homogeneously, temporally restricted.”

Let’s Talk

For a more in-depth discussion:

Contatta Maurizio Pavia – Partner

Contatta Piera Penna – Director