Can I submit the AD-1 declaration by PEC, or only via U2S/S2S?

Only U2S (fill in and submit from PUDM) and S2S (SOAP web service on the Nuova Piattaforma di Accoglienza) are accepted for the declaration itself. Paper filing is no longer permitted (Art. 8 DM March 10, 2026), and PEC is not a submission channel for the return. PEC is used only to send the procura to the relevant Ufficio delle Dogane when the Sottoscrittore is a third party.

What do state 198 and state 200 mean on the ADM receipt?

These are the two possible outcomes on a first- or second-level receipt. State 198 = Errore: the declaration was rejected for non-conformity (formal or substantive) and must be refiled after fixing the issues listed in the codice/descrizione fields. State 200 = accepted; the receipt may still contain Segnalazione or SegnalazioneConvalida elements - non-blocking warnings. Even with state 200, retain the receipts and any warnings for audit purposes.

Can a consultant submit the declaration on behalf of a power plant?

Yes. The consultant appointed as Sottoscrittore in MAU for that operator signs and submits with their own credentials. A procura is required: simple for power plants, notarized for sellers that invoice end customers (Circ. ADM 6/2022, prot. 53354/RU, February 4, 2022). The procura is sent by PEC to the relevant Ufficio delle Dogane and approved by ADM before the MAU appointment becomes operational.

Does the same digital certificate work for all my power plants?

Yes. The three-year ADM software certificate used in S2S is bound to the legal entity holding the Gestione Certificati profile, not to individual plants. One certificate per legal entity covers all the operator's power plants - and, for a portal or consultant acting under procura for multiple clients, it covers all clients for which the portal is the signing system. Natural persons (sole proprietorships without separate legal personality for the profile) cannot obtain the certificate and must use the U2S channel.

Submit AD-1 to the Italian Customs Agency (ADM) in 5 Steps

Q: Who must submit the AD-1 declaration to the Italian Customs Agency?

The semi-annual return is filed by the obligated parties under Art. 53 and 53-bis TUA: owners of production power plants (officine elettriche), including PV above 20 kW of available power used on site; sellers that invoice end customers; professional users with mixed use above 200 kW; self-producers; and renewable energy communities (CER) under D.Lgs. 43/2025. Distributors are not obligated parties. They fall under Art. 56-bis TUA, together with producers that inject their entire output into the grid, and owe no excise duty. They file an annual return on the energy they generate, inject into the grid, transport and distribute, the next one due by the end of March 2027 for tax year 2026 (Circ. ADM 9/D of May 7, 2026). Each power plant files its own return, even when the operator owns several plants.

Submitting the AD-1 declaration to the Italian Customs Agency (Agenzia delle Dogane e dei Monopoli - ADM) in 2026 is exclusively electronic for power plant operators (art. 8 DM 10 March 2026). Two channels are allowed: U2S (compile and submit directly from the web application of the Portale Unico delle Dogane e dei Monopoli - PUDM) and S2S (SOAP web service on the Nuova Piattaforma di Accoglienza, for third-party software). PEC is not a submission channel for the declaration: it is used exclusively to transmit the procura to the competent Ufficio delle Dogane when the Sottoscrittore is a third party. From January 1, 2026 the declaration is semi-annual under D.Lgs. 43/2025: H1 by September 30, H2 by March 31 of the following year. Sellers must additionally transmit monthly billing data from April 1, 2026 (art. 11 DM 10 March 2026). In every case the signature on the XML file is XAdES-BES enveloped, applied by the Sottoscrittore (MAU profile dlr_enelettr_sottoscrittore, mandatory since January 1, 2022). For the full quadri-and-deadlines picture, see the complete guide to the AD-1 declaration.

Quick definitions

ADM: Agenzia delle Dogane e dei Monopoli - the Italian customs and monopoly agency that administers electricity excise.
AD-1: Electricity consumption declaration set out in the TUA (D.Lgs. 504/1995); semi-annual from 2026.
PUDM: Portale Unico delle Dogane e dei Monopoli - ADM's native web application from which U2S submission is performed.
MAU: Modello Autorizzativo Unico - the profile framework governing access to ADM telematic services.
Sottoscrittore: Natural person registered in MAU with the dlr_enelettr_sottoscrittore profile (mandatory since January 1, 2022) who digitally signs the declaration.
U2S (User-to-System): Manual compilation and submission via the PUDM web application.
S2S (System-to-System): Automated submission via the SOAP web service on ADM's Nuova Piattaforma di Accoglienza. Requires a three-year software certificate.
XAdES-BES enveloped: Digital signature embedded in the XML file, conforming to the XAdES Basic Electronic Signature standard.
First-level / second-level receipt: ADM returns two asynchronous receipts: the first for formal checks (XSD), the second for substantive checks (cross-quadri logic).
State 198 vs state 200: State 198 = Errore (declaration rejected). State 200 = accepted, possibly with Segnalazione/SegnalazioneConvalida elements (warnings).

Prerequisites before submission

Before you can submit even a single declaration, you must align ADM access and authorizations. These steps are independent of which software you use.

SPID Level 2 (or CIE/CNS) for the legal representative of the company or sole proprietorship that owns the power plant.
MAU profile dlr_enelettr_sottoscrittore assigned to the signatory (legal representative or nominated third party). Mandatory since January 1, 2022: the old dlr_enelettr profile alone is no longer sufficient.
Procura if the Sottoscrittore is not the legal representative: simple for power plants, notarial for sellers who invoice end consumers (Circ. ADM 6/2022, prot. 53354/RU, 4 February 2022). The procura is sent via PEC to the competent Ufficio delle Dogane and approved by ADM before the nomination becomes operational.
S2S only: MAU "Gestione Certificati" profile in the legal entity + request for the three-year ADM software certificate. Natural persons cannot obtain the certificate and must use the U2S channel.

Channels: U2S vs S2S

The two modes cover different operational profiles.

U2S (User-to-System) - the operator compiles and submits via the PUDM web application. Suitable for those managing few plants (typically one or a handful of operators) or who prefer not to invest in third-party software. XSD validation is built in; the signature is applied by the Sottoscrittore at submission time.
S2S (System-to-System) - third-party software generates XML conforming to the ADM XSD, signs it and transmits via SOAP web service. Suitable for software houses, multi-client consultants and operators with many plants. Requires the three-year software certificate.

Regardless of the channel, the XML structure and ADM checks are identical. The difference is operational: how you compile, how you sign and how much you automate.

Procedure in 5 steps

Nominate the Sottoscrittore in MAU - the legal representative logs into PUDM with SPID L2 and nominates the natural person who will sign, assigning the dlr_enelettr_sottoscrittore profile. If a third party, accompany the nomination with the procura (simple or notarial by operator type).
Compile the AD-1 quadri - quadri required by the declarant category. Under the 2026 model, sales go in quadri J, L and M, settlement in Q (power plants) and S, and corrections are marked with the Rett flag inside J, L and M; there is no quadro I, K or P. See the guide to declarant categories and AD-1 quadri. Data must be consistent with the meter-reading register, sales invoices, and monthly down-payments already paid in the semester.
XSD validation- generate the XML file conforming to the XSD schema published by ADM (PUDM > Home > Servizi digitali > Web service) and validate before submission. In U2S, validation is built into the PUDM application; in S2S it is the third-party software's responsibility.
XAdES-BES digital signature - apply the enveloped signature to the XML file. In U2S, the Sottoscrittore signs with personal credentials. In S2S, the signature is automated via the three-year ADM software certificate bound to the legal entity.
Submit and handle receipts - submit via PUDM or the S2S web service. ADM returns two asynchronous XAdES-BES signed receipts: first level (formal/XSD checks) and second level (substantive checks). State 198 = Errore: redo after correcting the anomalies indicated (codice/descrizione fields). State 200 = accepted, possibly with Segnalazione or SegnalazioneConvalida (warnings without blocking). Retain both receipts for at least 10 years.

Deadlines

2026 deadlines derive from arts. 7-9 of DM 10 March 2026. For the complete calendar see AD-1 deadlines 2026.

H1 (January-June 2026) - the declaration was due by September 30, 2026. That deadline has passed; see the ravvedimento section below if you have not filed.
H2 (July-December 2026) - the next declaration, due by March 31, 2027 (art. 8 DM).
Monthly down-payments - by the end of each month, on the quantities invoiced (sellers) or consumed for own use (self-consumers) in the previous calendar month (art. 55(3) TUA; art. 7 DM). Any balance due is paid by the end of the month in which the semi-annual declaration is filed (art. 9 DM).
Monthly seller reports - from April 1, 2026, by the end of the month following the reference month, on the quantities invoiced in the reference month (art. 11 DM).

Common rejection causes and how to prevent them

The first level rejects for XSD non-conformity; the second level rejects for substantive inconsistencies. The most recurrent causes:

Obsolete XSD schema - the software uses an XSD version no longer valid (ADM publishes new versions typically around November 1 for the new declaration year).
Missing or invalid XAdES-BES signature - expired certificate, unsupported algorithm, non-enveloped signature.
Wrong codice ditta or license code - mismatch between the code in the XML and the code associated with the plant at ADM.
Sottoscrittore not nominated - MAU profile not active or procura not yet approved at submission time.
Cross-quadri errors at the second level - inconsistent sums between production (A), outflows (G/H), sales (J/L/M) and settlement (Q/S); monthly instalments that do not match down-payments already paid.

The practical rule is to validate the XML locally before submission and to keep a monthly register of consumption or billing data. Most second-level rejections come from data gathered just before the deadline.

Ravvedimento operoso if the deadline has passed

The H1 2026 deadline (September 30, 2026) has passed. Before ADM opens a formal assessment, omissions can be cured via ravvedimento operoso (art. 13 D.Lgs. 472/1997, extended to excise and customs by L. 225/2016). It is not available for a declaration filed more than 90 days late (art. 13(2-ter), violations from September 1, 2024); the payment side can still be cured. Payment is made with F24 ACCISE (not standard F24), Ente: D.

Tax code 2806 - electricity excise.
Tax code 2820 - interest (calculated at the statutory rate, accruing daily: 2% for 2025 and 1.60% for 2026; formula: tax x rate x days / 36500).
Tax code 2821 - penalty (excise chapter).

For late payment (violations from September 1, 2024, D.Lgs. 87/2024) the ravvedimento penalty scales with the delay: 0.0833% per day within 15 days, 1.25% at 16-30 days, 1.3889% at 31-90 days, 3.125% up to one year or the declaration deadline, and 3.5714% beyond. The identification code to report on the F24 is the codice ditta, not the VAT number.

Frequently asked questions

Who must submit the AD-1 declaration to ADM?

The semi-annual return is filed by the obligated parties listed in arts. 53 and 53-bis TUA: owners of production plants (including PV above 20 kW of available power used on site), sellers, professional users with mixed use > 200 kW, self-producers, CER. One declaration per plant.

Distributors are not obligated parties. They fall under art. 56-bis TUA, together with producers that inject their entire output into the grid, and owe no excise duty. They file an annual return on the energy they generate, inject into the grid, transport and distribute, the next one due by the end of March 2027 for tax year 2026 (Circ. ADM 9/D of May 7, 2026).

Can I submit via PEC, or only U2S/S2S?

Only U2S and S2S for the declaration itself: paper filing is no longer permitted. PEC is used exclusively to transmit the procura to the competent Ufficio delle Dogane.

What does state 198 vs state 200 mean?

State 198 = Errore (declaration rejected). State 200 = accepted, possibly with Segnalazione or SegnalazioneConvalida (warnings without blocking).

What happens if I miss the September 30, 2026 deadline?

The H1 2026 deadline of September 30, 2026 has passed. If you have not filed yet, file now: a late or omitted declaration is sanctioned under the TUA (art. 59(1)(c): 2 to 10 times the evaded tax, minimum EUR 258 per declaration; art. 50(1): EUR 500 to 3,000 as the general rule). Before ADM opens a formal assessment you can use ravvedimento operoso (art. 13 D.Lgs. 472/1997), but not for a declaration filed more than 90 days late (art. 13(2-ter), violations from September 1, 2024). Any excise paid late is cured by voluntary payment via F24 ACCISE (Ente D) with tax code 2806 for the excise, 2820 for interest and 2821 for the penalty. The late-payment ravvedimento penalty scales with the delay: 0.0833% per day within 15 days, 1.25% at 16 to 30 days, 1.3889% at 31 to 90 days, then 3.125% and 3.5714% (D.Lgs. 87/2024). The statutory interest rate is 2% for 2025 and 1.60% for 2026. The next deadline is H2 2026 (July to December), due by March 31, 2027.

Can a consultant submit for a power plant?

Yes, with the Sottoscrittore profile + procura (simple for plants, notarial for sellers, Circ. ADM 6/2022). The procura is sent via PEC to the competent Ufficio delle Dogane and approved by ADM.

Does the same certificate work for all my plants?

Yes. The three-year S2S software certificate is bound to the legal entity, not to individual plants: one certificate covers all the operator's plants and (for a portal acting under procura) all clients.

Next deadline

March 31, 2027 - semi-annual AD-1 declaration for H2 2026

Deklara compiles, validates the XSD, applies XAdES-BES signing, submits via S2S and handles ADM first- and second-level receipts.

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