Energy storage in photovoltaic systems in Italy

published on 8 May 2024 | reading time approx. 4 minutes

The further technical development and successful proliferation of systems for the storage of energy from renewable sources play a strategic role in the European's “roadmap" aimed at achieving the goals of climate neutrality and energy market independence. On the one hand, energy production and consumption are responsible for more than 75 per cent of greenhouse gas emissions in EU, making rapid and comprehensive decarbonisation of the energy sector a top priority. On the other hand, however, energy generation from renewable sources is “naturally" characterised by inflexibility and planning uncertainty in energy production and power supply.

Storage systems which recharge during periods of high productivity of the FER plants and release energy or electricity during periods of low productivity can compensate for this shortcoming.

The further technical enhancement of storage systems, the creation of clear legal regulations and an attractive framework for investors are therefore fundamental prerequisites for achieving the climate targets and for the competitiveness of (also) the Italian energy market today and in the coming years.

A brief overview of the integration of storage systems in photovoltaic plants, the applicable legal framework and the requirements for support (or its retention) by the Italian “Gestore dei Servizi Energetici” (GSE) is provided below.

Which types of storage systems exist in photovoltaics?

Storage systems that can be integrated into solar systems are special batteries that store the energy produced and make it available to consumers or the power grid in the evening, at night or during periods of low solar radiation.

A distinction is made between:

“One-sided” and “two-sided” storage systems (“sistemi monodirezionali” or “sistemi bidirezionali”): The “one-sided” systems only charge from the solar system, the “two-sided” systems charge from both the system and the electricity grid.
Upstream and downstream systems, with the former being installed upstream and the latter downstream of the inverter.

A distinction is also made between whether the photovoltaic system is connected to the national grid (“on grid”) or not (“off grid”). In the latter case, the systems are always equipped with an autonomous storage system. In the former case, on the other hand, the national grid acts as an “electricity storage facility”, so to speak, into which surplus electricity is fed during production and from which electricity is withdrawn when needed - during “production breaks”. If the system is also supplemented by an autonomous storage system, surplus electricity is primarily stored here and only released into the national grid when the battery’s maximum capacity is reached.

Which statutory regulations are applicable to the authorisation of storage systems in Italy?

For the authorisation of storage systems at Italian level, Art. 1 of Legislative Decree no. 7/2002 (as amended by Law no. 55/2002), Art. 62, paragraph 1 of Legislative Decree no. 76/2020 (so-called “DL Semplificazioni”) and Art. 31 of Legislative Decree no. 77/2021 as amended (so-called “DL Semplificazioni bis”) must be observed.

Administrative authorisation for the installation of electricity storage systems is granted in the following administrative procedures or by issuing the following administrative acts, depending on the capacity and location and whether the installation of the storage system involves the use of additional land:

in the simplified municipal authorisation procedure (so-called “Procedura abilitativa semplificata”, or PAS);
in the procedure for issuing the “Autorizzazione Unica” by the competent region or province pursuant to Art. 12 of Legislative Decree No. 387/2003;
in the procedure for the remodelling of installations pursuant to Art. 12 para. 3 of Legislative Decree no. 387/2003;
in “free construction” (so-called “edilizia libera”).

Installation of storage systems in photovoltaic systems subsidized by the GSE

As a rule, electricity storage systems can be installed in photovoltaic systems already subsidized by the GSE without losing the subsidy, provided that they are correctly integrated into the electricity grid, in other words the installation is carried out in compliance with the legal and regulatory provisions on connection, transmission, distribution, metering and settlement services and in accordance with the relevant technical regulations (CEI standards).

Solar installations with an output of less than 20 kW that are operated in on-site exchange (“scambio sul posto”) and are subsidized in accordance with the ministerial decrees of 28 July 2005 and 6 February 2006 (so-called “Primo Conto Energia”) however are an exception. Here, the installation of electricity storage systems is incompatible with the subsidy.

In cases where the installation of the storage system is carried out at the same time as the construction of the plant, registration in the so-called “GAUDI” system of TERNA must be carried out after submitting an application to the territorially responsible grid operator in accordance with the regulations of the so-called “Testo Integrato Connessioni Attive” (TICA).

If the storage system is integrated into already active plants, the applicant must update the registration entry in the GAUDI' system by entering all the information required for the storage system.

The GSE must be informed about the successful installation of the electricity storage system within 60 days of commissioning. The GSE will then carry out a legality check and inform the applicant of its successful outcome. Otherwise, in the event of irregularities, the GSE will initiate an administrative procedure in accordance with Law 241/90.