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 an annual communication on the flows only. 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). The H1 2026 return (January to June) was due on September 30, 2026 and that date has passed. The next one is H2 2026 (July to December), due by March 31, 2027 (DM 10 March 2026, Art. 8). A non-liable CER under Art. 56-bis TUA stays on the annual track 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 CER's legal representative, on file with the Italian Customs Agency (ADM), signs for the CER, 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. Only members fed over the power plant's own lines without their own POD run through Quadro G under outflow type A; members with their own POD are type B, with the sales in Quadri J, L and M.
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(2)(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 filer 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(2)(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 communication 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(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(2)(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(3)(b) TUA, but the exemption covers the tax, not the filing obligations. In the 2026 model that own use is reported in Quadro C under type L2, not in Quadro L.

Art. 53(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:

CER setup	Required AD-1 quadri
Own use of renewable generation above 20 kW, no supply to third parties	Quadro A, Quadro C (type L2), Quadro G. No Quadro L.
With supply to third parties	Quadri A, G, H, J, L, M, Q, S, N, T, plus Quadro C for any own use, and Allegati 1 to 4
With BESS (battery storage system)	As above, with the release from storage under outflow code R in Quadro G
With integrated RIU	As above, with members fed over the power plant's own lines without their own POD under outflow type A in Quadro G, and members with their own POD under type B plus the sales in Quadri J, L and M

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(1) TUA, and the CER appears as the filer in the cover sheet (frontespizio). Quadro G records every outflow from the plant under its destination code. Quadro C records own use. Quadri J, L, and M hold only the quantities billed to final customers.

2026 semi-annual deadlines

Semester	Reference period	Filing deadline
H1 2026	01/01/2026 to 30/06/2026	30/09/2026 (passed)
H2 2026	01/07/2026 to 31/12/2026	31/03/2027

The H1 2026 deadline has passed. For H2 2026, take the closing meter 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 communication, 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 entry (outflow type A in Quadro G for members fed over the power plant's own lines without their own 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

Confirm the CER holds an ADM license or authorization issued to the CER as a legal entity, not to individual members
Identify the technical setup: collective self-consumption only, grid supply, BESS, or RIU
Determine which AD-1 quadri are mandatory for that setup (see the table above)
Set up monthly metering of the kWh shared and supplied at each measurement point, which is required for monthly payments from 2026
Take the closing meter readings on December 31, 2026 for the H2 semester data
Calculate and post the surety bond (15% of estimated annual excise, per DM 10 March 2026)
File the H2 2026 declaration by March 31, 2027 if the CER is a liable party (the H1 deadline of September 30, 2026 has passed); if it is non-liable under Art. 56-bis TUA, file the annual communication by March 31, 2027

Legal sources

D.Lgs. 43 of March 28, 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 10 March 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 the declarant categories under the TUA.

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