Renewable Energy Communities (CER) and the AD-1 Declaration in Italy: Obligations, Declarant Categories and 2026 Deadlines

Renewable Energy Communities (CER, Comunità Energetiche Rinnovabili) formed under D.Lgs. 199/2021 fall under electricity excise obligations when they produce, share, or supply energy through the grid. Which declarant category applies depends on the setup: in the standard case, where generation goes into the grid and members draw from it on their own supply contracts, the CER is a non-liable party under Art. 56-bis TUA and files a flow-only return. It becomes a liable party under Art. 53 TUA only once it invoices electricity to end customers or consumes its own generation. That split also sets the filing frequency. A liable CER moves to the semi-annual AD-1 return from January 1, 2026 (D.Lgs. 43/2025), with a first deadline of September 30, 2026 for the H1 semester (January to June 2026). A non-liable CER under Art. 56-bis TUA stays on the annual return instead, next due March 31, 2027, because ADM Circular 9/D of May 7, 2026 keeps non-liable parties out of the new semi-annual filings. The declarant is the CER's legal representative on file with the Italian Customs Agency (ADM), not the individual photovoltaic self-producer or consumer members. Missing the deadline triggers a penalty of 100% to 200% of the tax due, with a €500 minimum. CER managers new to electricity excise should pair this article with our complete guide to the AD-1 declaration for the underlying quadri, deadlines, and rate logic.

Quick definitions

CER (Renewable Energy Community)

Standalone legal entity under D.Lgs. 199/2021 that aggregates renewable energy producers and consumers inside a geographic boundary set by GSE rules.

Declarant category of a CER

The CER itself as a legal entity, not the individual members. It is a liable party under Art. 53 TUA only when it invoices electricity to end customers or consumes its own generation; in the standard setup, with all generation fed into the grid, it is a non-liable party under Art. 56-bis TUA.

Collective self-consumption

Energy produced by CER plants and shared between members without any supply to third parties. Counts toward the excise calculation under Art. 52 TUA.

BESS

Battery Energy Storage System. There is no dedicated storage quadro: energy released from the battery to the grid is an outflow in Quadro G under destination code R.

RIU

Rete Interna d'Utenza: a private internal distribution network inside a delimited perimeter. Supplies to members run through Quadro G under outflow code A, or through Quadro I under sale code L when the member has no autonomous POD.

Semi-annual cadence

AD-1 filing frequency set by D.Lgs. 43/2025 for liable parties only: H1 (Jan to Jun) by September 30, H2 (Jul to Dec) by March 31 of the following year. Non-liable parties under Art. 56-bis TUA stay annual.

20 kW threshold

Available power (potenza disponibile) at or below which self-consumed renewable plants stay outside the scope of excise (Art. 52, c.2 lett. a TUA).

What is a Renewable Energy Community for excise purposes

A CER is a standalone legal entity (an association, cooperative, third-sector body, or not-for-profit company) that aggregates renewable energy producers and consumers inside a geographic boundary set by GSE rules. For excise purposes, ADM treats the CER as a single operator: the CER itself, not its members, holds the ADM license or authorization and files the AD-1 declaration. Each member stays responsible for their own final consumption, but the entity as a whole owns the declaration of energy produced and shared.

Which declarant category a CER falls into

The declarant is always the CER as a legal entity, never the individual members. Which category applies depends on how the electricity reaches the people who consume it:

• Renewable plant up to 20 kW of available power, consumed for own use: the electricity is not subject to excise (Art. 52, c.2, lett. a TUA). No license, no AD-1 return.
• Art. 56-bis TUA (non-liable party), the standard CER setup. Generation goes into the grid and members draw from the grid on their own supply contracts, so the excise is applied downstream by each member's seller. The CER still needs a power plant notice, a codice ditta, and an annual AD-1 return covering flows only. Not the semi-annual one: ADM Circular 9/D of May 7, 2026 expressly excludes the parties named in Art. 56-bis TUA from it. Next deadline: March 31, 2027 for tax year 2026.
• Art. 53, c.1 TUA (seller), if the CER invoices electricity to members or third parties and supplies them directly over its own line, bypassing the public grid. That is a supply to final consumers: the CER is a liable party and needs an operating license, a surety bond, and excise settlement.
• Art. 53, c.2, lett. a TUA (operator of a production plant for own use), if the CER consumes its own generation on its own premises. Above 20 kW, renewable self-consumption is exempt under Art. 52, c.3, lett. b TUA, but the exemption covers the tax, not the filing obligations.

Art. 53, c.3 TUA does not come into play here: it governs recognition on application for buyers that use electricity for a single purpose after transformation above 200 kW of available power, or that buy from two or more suppliers with monthly consumption above 200,000 kWh.

The declaration is signed by the CER's legal representative. When the CER runs both collective self-consumption and energy supplied to third parties, ADM may classify it as a consumer-seller and require additional quadri (sections).

Which AD-1 quadri a CER must complete

The mandatory quadri (sections) depend on the CER's technical setup:

Quadro A is a table of production meter readings, not an identification sheet: one row per fiscal meter with serial number, current and previous reading, difference, reading constant and kWh. The CER's own details - plant location, type and capacity in kW - are declared in the power plant notice under Art. 53-bis, c.1 TUA, and the declarant appears in the cover sheet (frontespizio). Quadro G records every outflow from the plant under its destination code, Quadro I records sales by type, and Quadro L records the exempt consumption, one block per month and per municipality.

2026 semi-annual deadlines

Take the first meter reading for the H1 declaration on June 30, 2026. Take the H2 closing reading on December 31, 2026.

This calendar applies to a liable CER. A CER that stays non-liable under Art. 56-bis TUA, with all generation fed into the grid and members drawing on their own supply contracts, never enters the semi-annual calendar. It files a single annual flow return, due March 31, 2027 for tax year 2026, on the December 31, 2026 reading.

CER with BESS or mixed use

CERs with battery storage systems (BESS) need to track energy charged into the battery separately from energy discharged, because the two volumes feed the excise calculation differently. Energy discharged from the BESS and supplied to final consumers is excisable. Energy self-consumed directly by CER members counts as collective self-consumption. Energy released from the battery into the grid is reported as an outflow in Quadro G under destination code R.

Mixed use, where part of the energy produced is self-consumed and part is supplied, requires separate accounting by intended use. A CER without separate metering across uses will struggle to complete the required quadri correctly.

CER vs RIU (Internal Distribution Networks)

A CER can aggregate plants and consumption points that are physically far apart, linked through the public distribution grid. An RIU (Rete Interna d'Utenza) is a private network connecting multiple injection and withdrawal points inside a physically bounded perimeter (e.g., an industrial site or a complex).

The distinction matters for ADM: supplies inside an RIU carry their own codes (outflow code A in Quadro G, or sale code L in Quadro I when the member has no autonomous POD), which a CER without an RIU never uses. A CER that also runs an internal RIU (e.g., condominiums with a shared private network) must declare the two perimeters separately.

Checklist for the CER manager

1. Confirm the CER holds an ADM license or authorization issued to the CER as a legal entity, not to individual members
2. Identify the technical setup: collective self-consumption only, grid supply, BESS, or RIU
3. Determine which AD-1 quadri are mandatory for that setup (see the table above)
4. Set up monthly metering of the kWh shared and supplied at each measurement point, which is required for monthly payments from 2026
5. Take meter readings on June 30, 2026 to close out the H1 semester data
6. Calculate and post the surety bond (15% of estimated annual excise, per DM March 10, 2026)
7. File the H1 AD-1 declaration by September 30, 2026 if the CER is a liable party; if it is non-liable under Art. 56-bis TUA, file the annual flow return by March 31, 2027

Legal sources

• D.Lgs. 43 of March 14, 2025, Arts. 53 and 56-bis TUA (liable parties, non-liable parties, and declarant categories)
• ADM Circular 32/2025, new intended uses and AD-1 quadri instructions for CERs
• DM March 10, 2026, semi-annual return, monthly payments, 15% bond
• D.Lgs. 199 of November 8, 2021, setup and rules for CERs in Italy
• D.Lgs. 504/1995 (TUA), Arts. 52 to 54, electricity excise legal basis

Deklara handles CER filing obligations end to end: from power plant registration to the semi-annual AD-1 declaration, with support for all 8 declarant categories under the TUA.

Further reading

• Complete Guide to the AD-1 Declaration: pillar reference on quadri, deadlines, and excise calculation.
• D.Lgs. 43/2025: What Changes for AD-1 Declarations in 2026: the reform that brought liable CERs into the semi-annual filing cycle.
• Italian Power Plant: Declarant Categories, ADM Licences, and Filing Obligations: the declarant categories CERs typically map to under Art. 53 TUA.
• DM March 10, 2026: Italy's Electricity Excise Implementing Decree: the implementing decree that locks in semi-annual deadlines and the 15% bond.