From April 1, 2026, every power plant (officina elettrica) operator must post a surety bond (cauzione) with the Agenzia delle Dogane e dei Monopoli (Italian Customs Agency, ADM) equal to 15% of the estimated annual excise duty. The formula: annual kWh consumed or transferred (from the plant declaration) x applicable excise rate x 15%. DM 10 March 2026, Art. 5 sets this rule under D.Lgs. 43/2025. Operators already active on December 31, 2025 had to comply by April 1, 2026. From then on the bond is adjusted every quarter so that it stays no lower than the arithmetic mean of the excise due over the three preceding months (Art. 10 of the same decree). Plants with SOAC (Soggetto Obbligato Accreditato) status can cut it by 30% to 100%. The bond is one piece of the wider AD-1 filing cycle; for the full picture, see our AD-1 overview.

Quick definitions

Surety bond (cauzione): Guarantee (bank guarantee or surety insurance policy) lodged with ADM to cover excise duty owed by the power plant.
15% formula: Annual kWh (from plant declaration) × applicable excise rate × 15%. Source: DM 10 March 2026, Art. 5.
Excise rate (Art. 52 TUA): Electricity excise rate in €/kWh; varies by use type (domestic, industrial, agricultural, public lighting).
Quarterly update: Every quarter the bond must be raised to an amount no lower than the arithmetic mean of the excise due over the three preceding months (Art. 55, c.11 TUA; DM 10 March 2026, Art. 10). No adjustment is needed if the increase would come to less than 10% of the bond lodged.
SOAC-GE: Accredited Operator status for gas and electricity (Arts. 9-ter to 9-octies TUA); Basic, Intermediate, and Advanced tiers cut the bond by 30%, 50%, and 100%.
Art. 22, c.1: Transitional provision of DM 10/03/2026: April 1, 2026 deadline to adjust bonds for operators already active on 31/12/2025.
Plant declaration (denuncia): Document filed with ADM's Ufficio Tecnico di Finanza listing identification data and estimated annual consumption and production figures for the plant.

What is the surety bond for power plants

The surety bond (cauzione) is a guarantee, typically a bank guarantee (fideiussione bancaria) or a surety insurance policy (polizza assicurativa cauzionale), that the power plant operator provides to ADM as a condition for the operating authorization. It covers the excise duty owed if the operator becomes insolvent. It is not a cash deposit with ADM: the document stays with the bank or insurance company while the plant is active, but ADM can call on it on default.

Before the D.Lgs. 43/2025 reform, the bond amount followed different criteria, often tied to fixed annual installments. The reform unifies the method with a single formula that applies to all declarant categories and updates quarterly.

The new formula: 15% of estimated annual excise duty

Multiply the annual kWh declared in the plant declaration by the applicable excise rate, then apply 15%:

Parameter	Example: industrial plant
Annual kWh (from plant declaration)	500,000 kWh
Rate, industrial use (Art. 52 TUA)	€0.0125/kWh
Estimated annual excise duty	€6,250
Surety bond (15%)	€938

The applicable rate depends on the intended use and the declarant category: domestic use (€0.0227/kWh), public lighting, industrial use, agricultural use, and so on. Plants with mixed uses apply a weighted average of the relevant rates.

Quarterly bond update

The bond is not fixed for the whole operating period. The mechanism (Art. 55, c.11 TUA, implemented by Art. 10 of DM 10 March 2026) does not measure the gap against the original estimate. It measures the excise actually due: every quarter the guarantee must be no lower than the arithmetic mean of the excise due over the three preceding months. The duty sits with the liable party, not with ADM.

Cadence and deadline: the adjustment is made by the end of the month following the reference quarter. Q1 by the end of April, Q2 by the end of July, Q3 by the end of October, Q4 by the end of January.
10% de minimis: no adjustment is required if the increase would come to less than 10% of the bond lodged (Art. 55, c.11 TUA).
Evidence within 10 days: documents proving the adjustment go to the competent office within ten days of the date it is made.
Re-determination by ADM: if the bond turns out to be inadequate on the data ADM holds, the office re-determines the amount and notifies it under Art. 64, c.2 TUA. The liable party then has thirty days from receipt to adjust and send the documents.
After the bond is drawn down: if unpaid excise in the three months before the draw-down exceeds twice the amount drawn (net of anything already entered for tax collection), the office re-determines the bond at the full unpaid excise for those three months. That re-determined amount stays unchanged for the following six calendar months.

Missing an adjustment is not a formality: under Art. 64, c.2 TUA it triggers revocation of the operating license or the authorization.

Who is affected

The surety bond requirement applies to liable parties under Arts. 52-54 TUA as updated by D.Lgs. 43/2025:

Sellers (Art. 53, c.1 TUA): anyone invoicing electricity to final consumers. Without a plant of their own the title is an authorization, not an operating license.
Operators of production plants consuming for own use (Art. 53, c.2 lett. a TUA): plants above 20 kW with full or partial self-consumption, holding an operating license. The exemption in Art. 52, c.3 lett. b covers the tax, not the bond.
Mixed-use consumers above 200 kW and buyers on the electricity market (Art. 53, c.2 lett. b and c TUA)
Parties recognized on application (Art. 53, c.3 TUA): single use after transformation above 200 kW of available power, or purchases from two or more suppliers with monthly consumption above 200,000 kWh
CERs and Internal Distribution Networks (RIU, Reti Interne d'Utenza) where they fall into one of the categories above, that is, where they invoice final consumers or consume their own generation

No bond is due from producers with available power (potenza disponibile) at or below 20 kW consuming for own use, which stay outside the scope of excise altogether (Art. 52, c.2 lett. a TUA), or from non-liable parties under Art. 56-bis TUA, typically those feeding all their output into the grid: with no excise due there is nothing to secure. Operators paying up front through an annual subscription charge, along with public administrations and public bodies, are also outside it.

Transitional rules: operators already active on 31/12/2025

Art. 22, c.1 of DM 10/03/2026 sets April 1, 2026 as the deadline to adjust the bond to the new formula for operators who already held an authorization on December 31, 2025. No official extensions have followed that date.

Compliance requires:

Calculate the new bond: kWh from plant declaration x applicable rate x 15%
Contact the bank or insurance company to amend the existing guarantee or issue a new document for the calculated amount
Deliver the updated document to the ADM Ufficio Tecnico di Finanza that covers the plant's territory

SOAC status and bond reduction

SOAC-GE status (Soggetto Obbligato Accreditato), introduced by Arts. 9-ter to 9-octies TUA, unlocks meaningful cuts to the bond:

SOAC Level	Bond reduction
Basic	30%
Intermediate	50%
Advanced	100% (full exemption)

The implementing decree that governs SOAC accreditation procedures had not been published as of early 2026; until it takes effect, SOAC status is not operational. For more on the overall reform, see D.Lgs. 43/2025 reform guide.

How to comply: bank or insurance

Calculate the estimated annual excise duty: multiply the kWh declared in the plant declaration by the rate that applies to your intended use.
Apply 15%: that is the bond amount to post.
Contact the bank or insurance company: request a bank guarantee or surety insurance policy for the calculated amount, made out to the Agenzia delle Dogane e dei Monopoli.
Submit the document to ADM: deliver it to the ADM Ufficio Tecnico di Finanza that covers the plant's territory.
Plan the quarterly update: set a reminder for the end of April, July, October, and January to work out the arithmetic mean of the excise due over the three preceding months and check that the bond you lodged covers it.

Legal sources

D.Lgs. 14 March 2025, n. 43: reform of the Testo Unico delle Accise (D.Lgs. 504/1995)
Art. 53-bis, c.1 TUA: bond requirement at 15% of the annual excise (c.4 exempts annual subscription payers, public administrations, and public bodies)
Art. 55, c.11 TUA: quarterly adjustment to the three-month arithmetic mean, notice within ten days, and the 10% threshold
DM 10 March 2026, Art. 5: bond set at 15% of the annual excise
DM 10 March 2026, Art. 10: quarterly adjustment, re-determination by ADM, and draw-down
Art. 64, c.2 TUA: revocation of the license or authorization for a missed adjustment
DM 10 March 2026, Art. 22, c.1: transitional deadline April 1, 2026
ADM Circular 32/2025: initial guidance on the 15% bond
Arts. 52 and 53 TUA: excise rates and liable parties

Deklara calculates the surety bond automatically from the plant declaration and alerts you when a quarterly update is due.

Power Plant Surety Bond in Italy 2026: The New 15% Calculation (D.Lgs. 43/2025)