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

Italy is a major European market for solar PV, onshore wind and battery energy storage (BESS), but a heavily subscribed transmission connection queue makes grid access a central development and investment risk. Connection applications far exceed the capacity expected to be built, and a preliminary grid solution does not necessarily mean that a project has a deliverable connection date.

Italy is also in the middle of its biggest change to grid connection rules in over a decade. This guide explains how the connection process works in 2026, how the rules have evolved, and what the new open-season regime means for developers, investors and acquirers. It covers Terna's application stages, distribution procedures, costs, timelines and the MACSE storage procurement mechanism. For comparisons with other markets, see our European Grid Connection Guide 2026.

• Transmission system operator (TSO): Terna S.p.A.
• Distribution system operators (DSOs): E-Distribuzione and regional operators, including Areti, A2A group operators and Ireti, depending on location.
• Regulator: ARERA (Autorità di Regolazione per Energia Reti e Ambiente).
• Connection status: Severe virtual saturation on the transmission network. Rules adopted in September 2026 replace first-come, first-served allocation with quarterly open seasons, with the first expected in early 2027.
• Connection timelines: Around 1–3 years for larger distribution-connected renewable projects (PF Nexus estimate). Transmission energisation is highly project-specific and can take several years; Terna's procedural deadlines are not physical connection dates.
• Costs and guarantees: No single nationwide €/kW amount applies to every connection. Charges, payments, securities and reinforcement obligations depend on network, capacity and project circumstances.
• BESS: Storage requires suitable grid connection rights; MACSE is a separate long-term storage capacity procurement mechanism, not a grid connection permit.

Italy's grid connection pipeline is far larger than the volume of projects likely to be built. According to Terna's 2025 Development Plan, requests to connect renewable generation to the national transmission grid reached approximately 348 GW at 31 December 2024, comprising:

• 152 GW of solar PV
• 110 GW of onshore wind
• 86 GW of offshore wind

Terna separately recorded approximately 277 GW of storage connection requests at the same date. By autumn 2026, pending renewable requests on the transmission network stood at around 314 GW, according to ADVANT Nctm. These figures represent applications, not operational, authorised or certain-to-be-built capacity. Multiple applications, development uncertainty and projects that will not progress all inflate the queue.

Italy's national energy and climate plan anticipates around 65 GW of additional renewable capacity by 2030. Set against a queue of more than 300 GW, applications exceed what is expected to be built by roughly four to five times.

Terna's 2025–2034 transmission development plan envisages more than €23 billion of grid investment. It also identifies a need for approximately 71.5 GWh of additional electricity storage by 2030, excluding existing pumped-storage plants. Grid investment and storage procurement support renewable integration, but neither removes the need to examine capacity at a specific connection point.

Transmission: Terna

Terna operates Italy's national transmission grid (Rete di Trasmissione Nazionale, RTN). Large renewable generation and storage projects may connect directly to this network, depending on location, the required capacity and the connection solution offered.

Distribution: Regional DSOs

E-Distribuzione is the largest distribution operator. Other operators serve specific territories. Distribution connections fall under ARERA's TICA framework (Testo Integrato delle Connessioni Attive), together with the applicable operator procedures.

The connecting network depends on the site and the technical solution, not on a fixed size threshold. Developers should confirm the correct operator before submitting an application.

Italy's transmission network suffers from what Terna calls virtual grid saturation: connection requests reserve or seek network capacity on a scale far exceeding the projects that will actually be built. The queue is congested on paper, but much of the capacity it holds is not backed by viable projects. The timeline below shows how the problem built up and how Italy has responded.

2008 onwards: TICA and first-come, first-served

ARERA's TICA framework established the main rules for connecting generation to Italian networks, and has been amended and supplemented many times since. For most of this period, transmission capacity was allocated broadly in order of application. Applying was relatively cheap, and a connection solution could be requested before a project had land rights or permits, so developers had a strong incentive to file early and hold queue positions.

2024: the queue peaks

As renewable and storage development accelerated, applications far outran network capacity. By 31 December 2024, Terna recorded approximately 348 GW of renewable generation and 277 GW of storage connection requests on the transmission network, against around 65 GW of additional renewable capacity needed by 2030.

2025: microzones, grid investment and MACSE

Terna's 2025 Development Plan set out more than €23 billion of transmission investment and a territorial planning approach dividing Italy into 76 microzones, to study connection needs and shared network solutions more efficiently. Microzones are planning areas, separate from Italy's wholesale electricity market zones.

On 30 September 2025, Terna held the first MACSE storage auction, awarding 10 GWh of contracted storage capacity (see below). Storage procurement and grid allocation began to move onto a more coordinated, planned footing.

2026: the DL Bollette and the open-season decree

Italy then legislated directly against virtual saturation. Article 7 of Decree-Law 21/2026 (the "DL Bollette") requires Terna to publish the maximum additional renewable and storage capacity available across the transmission network, updated every quarter.

A Ministry of Environment and Energy Security (MASE) decree signed on 8 September 2026 sets out how that capacity is allocated:

• Open seasons, at least quarterly: Terna publishes the capacity available in each microzone at least 30 days before each window, split between capacity available now and capacity requiring new grid works. Applicants choose a connection solution from that offer, rather than receiving capacity in order of application.
• "First authorised, first reserved": At the end of each open season, Terna issues an attestation. It becomes a binding capacity reservation only when the project notifies Terna that it has obtained its authorisation, with priority set by the authorisation's publication date.
• Existing connection solutions: Solutions issued for projects that are not yet authorised and have not been validated by Terna are expected to lose effect once ARERA publishes its implementing rules, with connection fees refunded or adjusted. Pending permit applications are not rejected as a result.
• Permitting deadlines: Authorisation applications must be filed within 90 days of accepting an assigned solution, and a lapsed authorisation takes its connection solution with it.

Late 2026 to 2027: implementation

The reform is still being put into practice. The expected sequence is:

• October 2026: Terna submits its microzone methodology to MASE for approval.
• Late 2026: ARERA's implementing rules on guarantees, priority and lapse, publication of the new microzones, and the first notices to holders of lapsing connection solutions.
• Early 2027: The first open seasons.

Check the status of these rules for any individual application, particularly for transmission-connected projects, where the lapse provisions are expected to have most effect. Developers can consult Terna's grid development plan and Econnextion resources for planning context, but published maps and queue figures should supplement, not replace, a formal site-specific connection assessment.

Transmission connection through Terna

Terna publishes a connection procedure covering the steps from an initial request to energisation. As the open-season regime takes effect, the way capacity is allocated will change, but the technical stages remain broadly as follows:

1. Prepare and submit the connection request. Provide the technical and project information required through Terna's current connection channel.

2. Receive the initial connection estimate and STMG. The Soluzione Tecnica Minima Generale describes the proposed general technical connection solution, including network arrangements and associated conditions.

3. Accept the estimate within the applicable deadline. Acceptance moves the process forward but does not by itself establish that the plant is authorised or ready to build.

4. Develop the connection design and obtain authorisations. The project and any relevant network works must proceed through the necessary technical and administrative stages.

5. Request and assess the STMD. The Soluzione Tecnica Minima di Dettaglio is the more detailed technical connection solution, developed later in the process.

6. Accept the STMD and enter the connection contract. Complete the applicable contractual, payment and security requirements.

7. Complete construction, commissioning and energisation. Both the generating or storage plant and the necessary network works must be ready.

GAUDÌ is Terna's generation-unit registration and data-management system, used to register plants rather than to submit the initial connection request. Consult Terna's current application guidance before filing.

Distribution connection through the relevant DSO

For a distribution connection, the developer applies to the operator serving the proposed site. Under the applicable TICA process, the operator assesses the application and issues a connection estimate (preventivo), subject to the necessary technical information and network analysis.

Following acceptance and required payments, the applicant proceeds with authorisations, connection works, plant registration where relevant, operating documentation and commissioning. A distribution connection can still involve extensive reinforcement or planning constraints, particularly for utility-scale generation and BESS.

For an operator example, see E-Distribuzione's guide for generation connections.

Italy does not have a single standard connection deposit or connection price applicable to every solar, wind or BESS project. It is important to separate four types of financial exposure:

• Application and assessment charges: Amounts due to prepare or process a connection estimate, according to the operator's published terms.
• Connection charges and staged payments: Amounts linked to the connection solution and the relevant TICA or Terna procedures. For some distribution connections, regulated calculations apply; larger or more complex solutions may involve project-specific terms.
• Security or guarantees: Financial commitments required at particular contractual or authorisation stages. ARERA is setting new guarantee rules for the open-season regime, so check the precise trigger, release and forfeiture terms for each project.
• Network works and reinforcement: Project-specific costs, delivery responsibilities and potential delays linked to substations, lines and other network infrastructure.

A low application charge should not be confused with the total cost of securing and delivering a grid connection. For an acquisition, the buyer should obtain the actual accepted connection documents, payment schedule, evidence of payments made, and the most recent estimate of outstanding network costs.

The applicable rules can be reviewed through ARERA's TICA guidance and the specific network operator's connection terms.

Published administrative processing periods are not the same as the time required to energise a project. For transmission connections, Terna's published procedure sets the following procedural stages:

• Initial connection estimate / STMG processing: 90 days.
• Acceptance of initial estimate / STMG: 120 days.
• Detailed solution (STMD) processing: 90 days.
• Acceptance of STMD: 60 days.

The overall timetable also includes authorisation and design stages that can materially affect the total duration. See Terna's official connection procedure.

For distribution connections, E-Distribuzione publishes the following offer-preparation periods for generation requests:

• Up to 100 kW: 20 working days to prepare the offer.
• Above 100 kW and up to 1,000 kW: 45 working days to prepare the offer.
• Above 1,000 kW: 60 working days to prepare the offer.

These are offer-preparation periods, not guarantees of a completed physical connection. See E-Distribuzione's guidance.

Indicative time to energisation: PF Nexus estimates around 1–3 years for distribution-connected renewable projects. Smaller and simpler projects may connect sooner, while constrained sites requiring extensive reinforcement or permitting can take longer. For transmission-connected projects, no dependable nationwide range applies: network upgrades, authorisations and the transition to open seasons can extend completion to several years or more.

The critical path may be determined by permitting, connection design, network reinforcement, land rights, procurement or construction rather than by the initial offer deadline. For project valuation or acquisition due diligence, the developer's projected date should be checked against written operator correspondence, the agreed connection solution and the construction schedule.

Italy is a major market for standalone and co-located battery storage. Terna reported 277 GW of storage connection requests as at 31 December 2024, but this is an application figure, not a forecast of batteries that will be built. Storage is included in the 2026 open-season reform, so BESS projects will compete for capacity in the same microzone windows as renewable generation.

BESS developers must distinguish between two separate questions:

1. Grid connection and operation: Whether the project can obtain and deliver its required import and export capacity, comply with applicable technical rules, and operate within any connection restrictions.

2. Revenue support and market participation: Whether the project can participate in wholesale, balancing, capacity or contracted storage procurement arrangements, including MACSE where eligible.

A project being eligible for a storage auction does not guarantee grid access. Conversely, an accepted grid solution does not guarantee a MACSE contract or any particular merchant revenue outcome.

What is MACSE?

MACSE (Meccanismo di Approvvigionamento di Capacità di Stoccaggio Elettrico) is Terna's electricity storage capacity procurement mechanism. It uses competitive auctions to procure storage capacity under long-term arrangements, compensating successful projects for capacity and services to the electricity system. MACSE procures storage capacity; it does not grant grid connection rights.

Terna held the first MACSE auction on 30 September 2025. According to its official announcement:

• 10 GWh of storage capacity was awarded in Southern Italy and the islands.
• Bids exceeded the volume sought by more than four times.
• The weighted-average clearing premium was €12,959/MWh-year.
• Contracted facilities from that first auction are scheduled to enter operation in 2028.

For investors, the result shows strong competition for contracted storage revenues. However, MACSE premiums should not be compared directly with merchant BESS revenues without considering contract terms, duration, operational obligations and the allocation of market risks.

• Virtual saturation: A place in the application queue may not translate into a deliverable connection timetable.
• Lapse of existing connection solutions: Under the 2026 reform, connection solutions for unauthorised projects that Terna has not validated are expected to lose effect.
• Authorisation-led priority: New capacity is reserved in order of authorisation, so permitting progress now directly determines grid position.
• Connection-stage uncertainty: A proposed STMG is not equivalent to a completed connection contract or energised asset.
• Grid reinforcement: New lines, substations or other network works can increase cost and delay completion.
• Financial commitments: Application payments, connection costs and any guarantees create capital requirements and potential forfeiture exposure.
• Storage revenue assumptions: MACSE-backed and merchant BESS projects face different pricing, eligibility and delivery risks.
• Project valuation: A grid-secured project may have a materially different value from one that has only submitted an application.

For transaction due diligence, developers and acquirers should review the original connection application, current STMG or STMD, evidence of acceptance, relevant contracts, financial obligations, authorisation status, network works and the latest correspondence with Terna or the DSO. Under the 2026 rules, buyers should also confirm whether the project's authorisation has been published and notified to Terna, and whether its connection is at transmission or distribution level, as these now determine whether capacity is actually reserved.

At PF Nexus, a renewable energy project is considered ready-to-build (RTB) only when all three pillars are secured and binding: land rights, grid connection and permits. An unaccepted grid offer or pending authorisation does not meet that standard. Investors comparing Italian projects can also use the PF Nexus Valuation Data Portal to benchmark RTB solar PV, onshore wind and BESS valuations across European markets.

Who operates Italy's electricity transmission grid?

Terna S.p.A. operates the national transmission grid. Distribution connections are handled by E-Distribuzione or another regional DSO, depending on the project's location and proposed connection arrangements.

How are Italy's grid connection rules changing in 2026?

Decree-Law 21/2026 and a MASE decree signed on 8 September 2026 replace first-come, first-served allocation on the transmission network with quarterly open seasons. Capacity is reserved in order of project authorisation, and existing connection solutions for unauthorised projects are expected to lose effect once ARERA's implementing rules are published. The first open seasons are expected in early 2027.

What is virtual grid saturation?

It describes a connection queue that is full on paper but not in reality. In Italy, connection requests far exceed the projects likely to be built, so capacity is tied up by applications that may never proceed. The 2026 reform is designed to release that capacity to projects that are ready to be built.

How long does a grid connection take in Italy?

PF Nexus estimates that distribution-connected renewable projects take around 1–3 years to reach energisation, although individual projects can fall outside this range. Transmission connections are more variable and may require several years or longer where major reinforcement is necessary. Terna's published administrative deadlines cover individual process stages, not completion of construction or energisation.

What is the difference between an STMG and an STMD?

The STMG is the initial general technical connection solution proposed during the Terna process. The STMD is the later, more detailed connection solution. Their preparation and acceptance are separate stages with different procedural deadlines.

What are Italy's grid connection microzones?

They are territorial planning areas used by Terna to model network needs and coordinate renewable connection solutions. Terna's 2025 plan defined 76 microzones, and under the 2026 reform microzones become the units in which connection capacity is offered through quarterly open seasons. They are separate from Italy's wholesale electricity price zones.

What does MACSE mean for BESS projects?

MACSE is a competitive procurement mechanism for electricity storage capacity. Winning an auction can provide contracted storage revenues, but the project still needs appropriate grid access, authorisations, financing and delivery capability.

Does receiving a connection offer make a project ready-to-build?

No. A project is not ready-to-build merely because it has applied for grid access or received a preliminary offer. For PF Nexus's RTB definition, binding land rights, an appropriately secured grid connection and final, binding permits must all be in place.

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Grid connection rules, costs and timelines vary across Europe. Our European Grid Connection Guide 2026 compares grid constraints, regulatory frameworks and reforms across six markets.

For more detailed country-specific information, see:

• United Kingdom – Grid Connection Rules, Timelines & Costs
• France – Grid Connection Rules, Timelines & Costs
• Spain – Grid Connection Rules, Timelines & Costs
• Sweden – Grid Connection Rules, Timelines & Costs
• Poland – Grid Connection Rules, Timelines & Costs

This guide draws primarily on transmission system operator, regulator and legal advisory publications:

• Terna – 2025 National Transmission Grid Development Plan, including queue data at 31 December 2024, planned infrastructure investment and the microzone framework
• Terna – Official Grid Connection Procedure, including STMG/STMD stages and published deadlines
• Terna – First MACSE Auction Results, October 2025
• ARERA – TICA Regulatory Guidance
• E-Distribuzione – Generation Connection Process
• ADVANT Nctm – Virtual grid saturation: the new open-season model and M&A impacts (September 2026)
• pv magazine Italia – New MASE decree on virtual saturation in force (September 2026)

Information reviewed: October 2026. The indicative 1–3 year distribution connection timeframe is a PF Nexus estimate based on market experience, not a statutory deadline. Queue figures are dated where given. The open-season regime is still being implemented, so verify applicable costs, guarantees, deadlines and connection status directly with Terna, ARERA and the relevant DSO before making investment or development decisions. This guide is general market information, not legal or technical advice for a specific connection application.