Do I owe Italian excise on my rooftop PV ≤ 20 kW?

No. Renewable photovoltaic plants with nominal power up to 20 kW are non sottoposti (outside the scope of excise) under Art. 52(2)(a) of the Testo Unico delle Accise (D.Lgs. 504/1995), as long as the electricity is self-consumed by the producer. No excise duty is owed and no AD-1 filing is required.

What if I export PV electricity to the grid?

Electricity exported to the grid (Scambio sul Posto or Ritiro Dedicato) goes to GSE or the local DSO and does not trigger an excise obligation for the producer: the supplier applies the duty downstream to the end customer. For plants above 20 kW, the self-consumed share can still be exempt under Art. 52(3)(b), but the AD-1 filing is still required.

Is residential PV ≤ 3 kW exempt?

Yes, on two grounds. It is non sottoposto thanks to the 20 kW threshold (Art. 52(2)(a)), and residential supplies up to 3 kW of contracted power with average monthly consumption of 150 kWh or less also qualify for the full exemption under Art. 52(3)(e) TUA.

What is impiego promiscuo (mixed use) under Art. 52(4) TUA?

Impiego promiscuo describes a power plant that feeds both exempt internal uses and taxable third-party uses. The trigger is when the power made available to third parties at the same delivery point exceeds 200 kW: at that point the entire power plant needs a licence and an AD-1 filing, and separate metering is required for each end use.

Which AD-1 quadri must a PV producer file?

A self-consuming PV producer above 20 kW typically files quadri A (plant identification), B (production), E (exempt consumption), and G (excise calculation). Paid sales to third parties add quadro C; tax credits add H; corrections to prior periods add L.

When are the 2026 deadlines for PV declarants?

Under D.Lgs. 43/2025 the cadence is semi-annual: H1 (January-June) is due by September 30, 2026; H2 (July-December) is due by March 31, 2027. Taxable plants also pay monthly advances by the end of the reference month.

Photovoltaic Electricity Excise in Italy: Thresholds, Exemptions and AD-1 Filing in 2026

Italian electricity excise applies to photovoltaic output only in specific cases. The anchor rule is Art. 52(2)(a) of the Testo Unico delle Accise or Italian Excise Code (D.Lgs. 504/1995): renewable plants up to 20 kW of nominal power used for self-consumption are non sottoposti (outside the scope of excise), so they need neither a licence nor an AD-1 filing. Residential supplies up to 3 kW with average consumption of 150 kWh/month or less qualify for a further exemption under Art. 52(3)(e). For plants above 20 kW, electricity self-consumed by the photovoltaic self-producer for non-residential uses is generally exempt under Art. 52(3)(b), but the owner still runs a power plant and must file the AD-1. When the same delivery point serves more than 200 kW of third-party demand, impiego promiscuo (mixed use, Art. 52(4)) applies and the entire power plant becomes taxable. For 2026, under D.Lgs. 43/2025, the cadence is semi-annual: H1 is due September 30, 2026, H2 by March 31, 2027. For the general filing framework see the complete guide to the AD-1 declaration.

Quick definitions

Photovoltaic (PV): Plant that generates electricity from sunlight through photovoltaic conversion. For excise purposes, a textbook renewable source governed by Art. 52 TUA.
Self-consumption (autoconsumo): The share of electricity produced and consumed by the same entity that owns the plant, with no supply to third parties. This is the deciding variable for the exemption.
Nominal power (potenza nominale): DC power of the modules (kWp) or, in ADM practice, the inverter's AC output power. Multiple plants on the same point of connection are aggregated.
Non sottoposto vs. esente: A key distinction. Non sottoposto = outside the scope of excise duty (no obligations at all). Esente = inside the scope but at a zero rate (the power plant still exists and the AD-1 must still be filed).
Impiego promiscuo (mixed use): Setup where a power plant feeds both exempt and taxable uses. When the power available to third parties at the same delivery point exceeds 200 kW (Art. 52(4)), the entire plant becomes taxable.
RIU (internal user grid, rete interna di utenza): A private network under Art. 33 of Law 99/2009 that connects multiple consumption units to one or more generation plants without a public-grid connection. For excise purposes, it counts as a power plant whose declarant category is "self-consumer" or "seller-distributor".
BESS (battery storage): Electrochemical storage system. If charged only from PV for self-consumption, it does not affect the exemption. If charged from the grid and discharged to third parties, it can count as a supply and trigger excise duty.
Semi-annual cadence: Filing frequency introduced by D.Lgs. 43/2025: H1 due September 30, H2 due March 31 of the following year. Replaces the previous single annual filing on March 31.

When excise applies to PV electricity

The answer turns on three variables: nominal power, where the electricity goes (self-consumption or supply), and type of end user (residential or non-residential). Their combination places the plant in one of four bands:

Non sottoposto - self-consuming plants up to 20 kW. No ADM obligations at all.
Exempt, residential - household supplies up to 3 kW with average consumption of 150 kWh/month or less (Art. 52(3)(e)). The supplier applies the exemption to the end customer.
Exempt with filing obligation - non-residential self-consuming plants above 20 kW (Art. 52(3)(b)). The owner runs a licensed power plant, files the AD-1, and pays zero on the self-consumed kWh.
Taxable - paid supply to third parties and any setup that falls under impiego promiscuo above 200 kW.

The 20 kW threshold (art. 52 c.2 lett. a TUA)

The 20 kW threshold is the first dividing line and the one most often misread. What counts toward the limit is the aggregate nominal power of plants connected to the same point of connection, not the individual string or inverter. ADM practice (circular 17/D 2018 and subsequent acts) clarifies several operational points:

All plants on the same POD are summed, even if installed at different times and under separate authorisations.
For plants with DC and AC sections, the AC nominal power of the inverter is used, unless the module power is lower (the smaller value prevails).
A revamping that pushes the plant to 21 kW causes the exemption to lapse: power plant notification and new licence are due within 30 days.
Operating multiple plants < 20 kW on different PODs keeps each one outside the scope even if the aggregate exceeds 20 kW.
Batteries and storage do not count toward the threshold if charged exclusively from renewable sources.

Residential exemption ≤ 3 kW (art. 52 c.3 lett. e)

For the residential segment two favourable regimes overlap. PV ≤ 20 kW is already non sottoposta; in addition, supplies to a primary residence (residenza anagrafica) with contracted power ≤ 3 kW and average monthly consumption ≤ 150 kWh enjoy a full exemption on the entire supply (including the share drawn from the public grid). The benefit is administered directly by the supplier, who does not bill the excise; the PV producer is not involved.

Plants > 20 kW in non-residential self-consumption (art. 52 c.3 lett. b)

The textbook case: industrial rooftop, winery, hotel, livestock farm with a 50-500 kW rooftop array. The c.3 lett. b exemption states that electricity from renewable plants self-consumed by the producer at its own premises is not subject to excise. However all formal obligations remain:

Power plant notification to the competent ADM office.
Acquisition of an operating licence (codice ditta) within 30 days of energisation.
Posting of collateral at 15% of the projected annual excise liability (art. 10 DM 10 March 2026).
Installation of UTF/ADM fiscal meters measuring gross and net production.
Semi-annual AD-1 filings.

Mixed use: when the power plant feeds > 200 kW (art. 52 c.4)

Art. 52 c.4 is the anti-avoidance clause. When a power plant simultaneously supplies exempt and taxable uses, and the power made available to third parties at the same point of delivery exceeds 200 kW, the entire plant falls into impiego promiscuo. Consequence: all generated electricity is treated as taxable unless the exempt destination is proven through separate metering. Concrete example: an 800 kW PV park serving an industrial consortium where a single off-taker draws more than 200 kW qualifies the entire plant as mixed use; separate meters per off-taker and full reporting of every flow in quadri B-C-E are mandatory.

Which AD-1 quadri a PV producer must compile

The mix of quadri depends on the declarant category. A self-consuming PV exempt operator with a plant > 20 kW compiles four core quadri; one supplying third parties adds one more.

Quadro	When a PV producer compiles it
A	Always. Plant identification: codice ditta, location, power, renewable type.
B	Always for plants > 20 kW. Gross and net solar production in the half-year.
C	Only if there is supply to third parties for consideration (e.g. sale to adjacent SEU, direct sale).
E	Always for exempt self-consumption: kWh self-consumed by the producer at its own premises.
G	Always. Excise calculation: for a purely exempt PV producer the result is zero, but the quadro must still be filed.
H	Only when tax credits are present (e.g. refunds of advance payments not actually due).
I	Summary of payments made. For purely exempt PV producers typically empty.
L	Only when correcting prior periods.

2026 deadlines for PV declarants

The unified calendar introduced by D.Lgs. 43/2025 applies to photovoltaic producers as well:

H1 2026 (1 January - 30 June 2026): AD-1 filing due by 30 September 2026.
H2 2026 (1 July - 31 December 2026): AD-1 filing due by 31 March 2027.
Monthly advance payments: for taxable plants, settlement by the 16th of the following month (art. 11 DM 10 March 2026). Purely exempt producers pay no advances.
Change notifications: every change of power, declarant or configuration (e.g. installation of a grid-connected BESS) must be notified to ADM within 30 days.

Common mistakes in PV declarations

Missing aggregation of plants on the same POD: two 12 kW plants installed two years apart on the same point of connection together exceed the 20 kW threshold. Continuing to declare each as non sottoposto is a recurring error that ADM picks up in inspections.
Conflating non sottoposto with esente: filing an AD-1 in "exempt" mode for a ≤ 20 kW plant is not just superfluous - it creates a power plant entry in the ADM register that cannot be reversed without procedure.
Forgetting the 200 kW trigger: crossing the third-party-available power threshold without reconfiguring the metering and accounting is the classic case disputed in consortia and shopping centres.
Outdated regional surcharge: for PV producers selling to third parties, the regional surcharge can be revised annually. Using last year's values exposes the filer to penalties.
Failure to notify within 30 days of a revamping that pushes power above the exemption threshold: the delay configures unauthorised operation of a power plant with administrative sanctions.