The Lazio Regional Administrative Court’s (TAR) reversal on the legitimacy of Regional Guidelines for the development of RES plants

With Decision no. 6969, published on 8 April 2025, in a case brought by a company that had received a notice of inadmissibility regarding its PAUR application for the construction and operation of an agrivoltaic plant in the municipality of Acquapendente (VT), the Lazio Regional Administrative Court (TAR) declared unlawful the Guidelines adopted by the Regional Council through Resolution no. 171 of 12 May 2023. These Guidelines provided transitional criteria and guidance for the development of renewable energy sources (RES) and the issuance of the PAUR pursuant to Article 27 bis of Legislative Decree no. 152/2006, specifically for ground-mounted photovoltaic and wind power plants in the Lazio region.

It is important to recall that the Lazio Region’s approval of these Guidelines occurred while awaiting the adoption, by individual Regions, of Ministerial Decrees identifying suitable and unsuitable areas for the installation of renewable energy plants, pursuant to Article 20, paragraph 1, of Legislative Decree no. 199/2021. Through these same Guidelines, the Lazio Region, on the one hand, gave priority to initiatives located in areas already considered suitable under Article 20, paragraph 8, of Legislative Decree no. 199/2021, or related to the development of RES as part of the implementation of the PNRR (National Recovery and Resilience Plan), the Complementary National Plan, and the 2021–2027 Cohesion Programming. On the other hand, however, it conditioned the activation of the PAUR process on a principle of proportionality and subsidiarity among provinces, allowing for RES development in each province only up to a maximum of 50% of the total MWp authorized across the region.

Given the high concentration of RES plants in the Province of Viterbo (which currently hosts around 78% of all RES installations in Lazio), the Guidelines effectively imposed a ban on the authorization of any projects in that province unless they fall within the “priority” category or are located in suitable areas. This effectively prevents the initiation of authorization procedures for all other cases.

Contrary to what was ruled in Decision no. 23856, published on 31 December 2024, the same Lazio TAR found that these Guidelines conflict with the provisions of paragraphs 6 and 7 of Legislative Decree no. 199/2021, as they introduce a moratorium on non-priority projects in areas not deemed suitable. They also conflict with the guidelines set forth in the Ministerial Decree of 10 September 2010, effectively imposing a preliminary ban on RES project development in a significant portion of the regional territory, and they contravene established constitutional case law, which has reaffirmed the binding nature of national guidelines to ensure uniform regulation across the country.

The Court, while confirming that Regions may introduce proportionality and subsidiarity criteria to promote balanced RES development at the regional level, ultimately ruled that Resolution no. 171/2023 constitutes a true “a priori ban on initiating the necessary procedural assessment”, resulting in “an inevitable illegitimacy due to violation of fundamental principles governing the sector”.