DM Saturazione: the new rules for grid access
In less than two years, the rules for connecting a renewable plant or an energy storage system to Italy’s national transmission grid (RTN) have been rewritten three times. The latest step, MASE Ministerial Decree 291 of 8 September 2026, changes the underlying logic: what matters is no longer who applies first for a connection, but who obtains the permit first. From first come, first served to first permitted, first connected.
The problem: virtual grid saturation
In recent years, a large number of connection solutions were requested and “booked” by initiatives that would never reach authorisation, locking up capacity at the expense of more mature projects. As of 31 May 2026, 9,204 requests were pending on the RTN, for 318 GW of renewables and 294 GW of storage: figures far above both Italy’s 2030 targets and the physical capacity of the grid.
The legislative path in three steps
- Legislative Decree 190/2024 (Consolidated Act on renewable permitting, amended by Legislative Decree 178/2025): reduces permitting regimes to three (free activity, simplified PAS procedure, Single Authorisation) and, with Art. 10-bis, introduces the first comprehensive framework for grid connections. Terna may issue solutions even beyond available capacity, but final allocation is reserved for those holding a permit.
- Decree-Law 21/2026 (the “Bills Decree”, converted by Law 49/2026): rewrites Art. 10-bis, provides that connection solutions already issued but not validated lose effect, protects projects with an EIA or EIA exemption, and requires Terna to publish the available capacity for each portion of the grid every quarter.
- MASE Ministerial Decree 291/2026, in force since 9 September 2026: the implementing decree that makes the new system operational.
How it works, step by step
- Terna defines the microzones and calculates the additional capacity that can be accommodated, totalling at least 150% of the 2030 targets and updated at least quarterly.
- At least 30 days before each Open Season, Terna publishes the Offer on its Terra portal: available capacity, status of RTN works, connection points and data on pending requests.
- During the Open Season, applicants choose a solution and receive an Attestation, which allows them to apply for a PAS or Single Authorisation.
- If new RTN works are needed, the technical approval (Benestare) is issued only after Terna has obtained the relevant permits. The 90-day deadline for filing the permit application runs from the Benestare.
- Once the permit is obtained, the final capacity reservation follows the chronological order of permit publication, which must be notified to Terna by the following day (within 3 working days of the start of works for free-activity projects).
If the connection point becomes saturated in the meantime, applicants holding only an Attestation lose it: Terna proposes either the RTN works needed to keep that point or an alternative solution close to the plant, and any ongoing permitting procedure is suspended for the time needed to adapt the connection.
What happens to solutions already issued
Within 15 days of ARERA’s implementing measures, Terna will notify the loss of effect of existing solutions. Only those with an already validated Technical Plan of RTN Works, or with RTN works already authorised or in place, remain confirmed. Projects with a favourable EIA, an EIA exemption or a positive environmental opinion must notify Terna within the same 15 days: Terna will assess whether to include the related works in the Offer, but this is not automatic.
Deadlines to watch
Almost all transitional deadlines run from the publication of ARERA’s measures on grid connections (conditions, Open Season rules, overbooking and priorities). The deadline for adopting them expired in August 2026 and, at the time of writing, they have not yet been published: once they are, very short windows will open. In the meantime, Terna was due to submit its proposed methodology for defining the microzones to MASE by 9 October 2026. The Ministry may request clarifications or additions within 30 days; once approved, Terna has 15 days to publish the microzones, which are therefore expected around the end of November. The first Open Seasons are realistically expected in 2027.
What to check in your portfolio now
- Permit already obtained: check that the permit publication was notified to Terna on time. A late notification can cost you the Attestation.
- Solution obtained, PAS or Single Authorisation still pending: the most delicate case. If the Technical Plan of RTN Works has not been validated and the RTN works are neither authorised nor in place, the solution is at risk and it pays to speed up the permitting process.
- EIA or EIA exemption obtained, connection not yet validated: the notification to Terna must be sent within 15 days of ARERA’s measures, so it is worth preparing it now. A solid connection design makes the difference.
- No connection request filed yet: no urgency, but now is the time to monitor microzones and the Offer in your area of interest and prepare the project for the first available Open Season.
In short
The system moves from solutions issued without transparency on actual capacity, with priority tied to the request date, to one with capacity published by microzone, periodic Open Seasons and a clear distinction between Attestation (provisional) and Reservation (final, tied to the permit). The value of a project shifts even further towards the quality of its permitting process and connection design: a factor to weigh in due diligence and M&A transactions too.
Want to understand how the DM Saturazione affects your projects?
Our team works every day on high-voltage connections, Technical Plans of RTN Works and permitting for renewable and BESS projects. Tell us where your projects stand: we will help you understand which case they fall into and what is worth doing before ARERA issues its measures.
Or write to us at engineering@gridshape.it