Grid Connection in Italy: Rules, Timelines, Costs for Renewable and BESS projects

Summary

• Grid operator: Terna SpA (Transmission); E-distribuzione + 120 regional DSOs (Distribution)
• Regulator: ARERA
• Connection Status: Saturated / Reforming (Transmission); Open (Distribution)
• Timeline: Transmission varies; 1-3 years distribution
• Security Deposit: Not publicly standardised
• BESS Rules: 277 GW in queue; MACSE procurement mechanism; new ARERA dispatch rules

Voltage Threshold

Transmission: (≥150 kV / ≥10 MW)

Distribution: (<10 MW)

1. Market snapshot 

Italy has an overwhelmed and oversubscribed grid connection queue. The figure below shows the extent of the situation - as of December 2024 the transmission queue held more than 350 GW of generation (roughly 152 GW of solar and 196 GW of wind) against a national 2030 renewable target of only 65 GW. Roughly five times more capacity is queued than the country plans to build this decade.

Source: Terna, December 2024.

2. Grid providers

• Transmission (TSO): run by Terna SpA (Gestore della Rete di Trasmissione Nazionale)
• Distribution (DSO): run by e-distribuzione (Enel Group, the largest Italian DSO) plus around 120 regional DSOs, including ACEA Distribuzione (Rome), A2A Reti Elettriche (Lombardy), and Ireti (Iren Group, Genoa/Turin). 
• Regulator: ARERA - governs the entire connection framework through TICA (Testo Integrato delle Connessioni Attive).

3. Connection status and queue 

Italy's transmission grid is in a state of “virtual saturation” - the connection queue is jammed. The root cause is the first-come-first-served model (FCFS) which allows developers to file applications to hold queue positions clogging the system with speculative projects that may never be built.

Starting in 2021, a system involving a micro zone-based reform is currently under way splitting Italy into 76 “microzones” for more coordinated connection zones (Strategic Energy, 2025). This differs from the FCFS queue by processing applications by zone. As a result, new connection timelines remain uncertain and will remain until the open-season mechanism is implemented.

4. Application Process 

Transmission (TSO) (Terna): Register and apply online via the GAUDÌ system and connessioni.terna.it. Terna carries out a preliminary feasibility check before initiating the STMG (Soluzione Tecnica Minima Generale - the minimum general technical connection solution). The STMG is issued within 60 working days (~3 months) of complete application documentation, with a 20-working-day persistence check. The developer must then accept or reject the STMG within a regulatory deadline (typically 30–60 days). Security is required on acceptance.

• Connection timeframe: Highly uncertain due to queue saturation (TBC)

Distribution (DSO): Apply to the relevant DSO - e-distribuzione via its online portal, other DSOs via their own portals. The process is governed by TICA: 60 working days for documentation validation, 20 working days for the persistence check, and typically 30 days to accept the offer once issued.

• Connection timeframe: 1-3 years for utility scale projects. Subject to grid availability and DNO queue

5. Costs and financial requirements 

• Transmission connection fee: Forfait proportional to connection power
• Distribution connection fee: Forfait per TICA schedule
• Distribution security: Per TICA framework

Italy uses a forfait fee proportional to connection power at both transmission and distribution level. 

6. Timelines 

• STMG issuance (transmission): 60 working days from complete application
• Persistence check: 20 working days
• STMG acceptance window: 30-60 days
• Distribution documentation validation: 60 working days
• Distribution acceptance window: 30 days
• Transmission energisation: (Uncertain)
• Distribution energisation: 1-3 years

The STMG official connection proposal is issued by Terna outlining the connection point, voltage level and cost to deploy a RE plant to the electrical grid. The process is quick - about three months however transmission energisation timelines are currently unpredictable due to queue saturation.

7. Battery storage (BESS) rules

277 GW of BESS requests have been registered as of December 2024, and storage is included within the microzonal planning process. At distribution level, BESS under 10 MW falls under the TICA/ARERA framework, with systems up to 1 MW able to connect at low voltage (BT), and flexible connection options are available.

MACSE mechanism (Meccanismo di Approvvigionamento di Capacità di Stoccaggio Elettrico) is a capacity procurement scheme designed specifically to bring forward critical storage Italy currently needs in the grid. It provides flexible access capacity allowing the regulator to limit charging/discharging depending on grid conditions. 

Italian storage sits on effectively its own track - a huge separate queue, a purpose-built procurement mechanism (MACSE), and dedicated dispatch rules - rather than being folded into generation as it is in the UK or France.

8. Recent reforms and what’s next

• 2008 - TICA (Testo Integrato delle Connessioni Attive) framework established under ARERA
• *2021 - Ongoing - Microzonal reform: 76 microzones with collective coordinated connection solutions and "open season" windows, replacing FCFS. Timelines still to be confirmed as the mechanism is implemented.
• 2024 - DL Bollette reform: legislative basis for the queue overhaul
• Dec 2024 - Queue reaches 350+ GW generation / 277 GW storage vs 65 GW 2030 target 
• 2025 - ARERA Resolution 281/2025: strengthened grid-access requirements

9. Risk factors

• Transmission timelines unpredictable - until microzonal open-season mechanism is fully live there is no reliable timeframe for a new transmission connection
• Fees and deposits not publicly standardised - Connection forfait and security deposit have no published single figure.
• Queue saturation - 5x oversaturated queue will take time to clear up under reform. Deliverability of any project is uncertain

PF Nexus statement:

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This country profile forms part of our wider guide to grid connection across Europe, which compares regulatory status, connection costs, security requirements and timelines across major European markets.

See related markets such as: United Kingdom, Spain, France

Sources

Terna (terna.it/en/grid-connection; connection procedure) 

Terna Econnextion storage/renewable connection map (dati.terna.it/en/econnextion)

Connessioni Terna / GAUDÌ portal (connessioni.terna.it)

ARERA (arera.it; TICA; Resolution 281/2025)

Strategic Energy Europe ("Italy Redefines Power Grid: Terna Microzones") (https://www.energiaestrategica.com/strategicenergy/en/notes/italy-grid)

Chambers & Partners (Renewable Energy 2025 — Italy)

https://lightbox.terna.it/en/insight/new-electricity-market-zones