On a company's gas bill two steps affect the total as much as the price: how the cubic metres on the meter become billed Smc, and the excise regime applied. For delivery points with annual consumption below 200,000 Smc, the bill format set by ARERA has applied since 1 July 2025; above that threshold the layout depends on the supplier, while the items stay the same.
From the meter to Smc
The meter measures cubic metres; the bill is in standard cubic metres (Smc), obtained by multiplying cubic metres by the C coefficient, defined for each locality and linked to delivery pressure and temperature. In the example in the ARERA glossary, 110 m³ with C equal to 1.027235 become 112.99585 Smc.
The gross calorific value (PCS) indicates how much energy one Smc contains and is used to move from prices in €/GJ or €/MWh to prices in €/Smc. With the reference value used by ARERA, 0.038520 GJ/Smc, one Smc equals about 10.7 kWh; the value applied on the bill may differ, and should be checked when comparing offers expressed in different units.
The items on the bill
| Item | What it contains | Who sets it |
|---|---|---|
| Natural gas supply cost (spesa per la vendita) | Wholesale procurement and retail marketing, as fixed and consumption charges | The contract with the supplier |
| Network tariff (tariffa per l'uso della rete) | Transport, distribution and metering: charges that also depend on the meter class, as a fixed charge and an energy charge by consumption tier | ARERA |
| General system charges (oneri generali di sistema) | Energy saving and renewables, compensation of marketing costs, last-resort services | ARERA |
| Taxes | Excise duty, regional surcharge and VAT | State and Regions |
Excise duty: domestic and non-domestic use since 2026
Since 1 January 2026, Legislative Decree 43/2025 has replaced the distinction between "civil use" and "industrial use" with the one between "domestic use" and "non-domestic use", leaving the rates unchanged. In the table of the Italian Customs and Monopolies Agency updated on 6 October 2026:
- non-domestic use: 0.012498 €/m³, reduced by 40% for industrial users, thermoelectric plants excluded, with consumption above 1,200,000 m³ a year;
- domestic use: from 0.044 to 0.186 €/m³ depending on the annual consumption tier (from 0.038 to 0.150 €/m³ in the southern "Mezzogiorno" territories).
The non-domestic rate is not automatic: the seller applies it from the date it receives a self-declaration stating the activity carried out and the uses of the gas. The perimeter also matters: company offices located outside the plants are taxed as domestic use, while offices, canteens and service premises inside the production site follow the non-domestic rate. Gas used in chemical reduction and in electrolytic, metallurgical and mineralogical processes is not subject to excise duty. If a single delivery point feeds uses taxed differently ("mixed use"), the split must be requested from the supplier with a sworn technical report: without documents the whole supply follows the taxation stated in the contract.
VAT is 10% for gas used by mining, agricultural and manufacturing companies, upon written request with a declaration of the requirements; 22% for other industrial uses.
For a business: what to check
- Metering — check the C coefficient and the meter class shown on the bill, and tell actual readings, estimates and recalculations apart.
- Excise regime — check site by site which rate is applied: between 0.012498 and 0.186 €/m³ the gap is almost fifteen-fold. Since 2026, activities previously excluded fall under non-domestic use, including theatres, cinemas, museums and nursing homes.
- Supplier switch — the declaration for the non-domestic rate and the mixed-use request must be submitted again to the new seller: continuity of the tax treatment is guaranteed only if it receives them within a reasonable time.
- Large consumption — 40% reduction above 1,200,000 m³ a year, process exclusions, CSEA list of gas-intensive companies: check whether you qualify.
- Price — identify the index (PSV or TTF), the spread and the PCS used in the conversion; trends are on the market indices page.
- Continuity — if it is left without a supplier for reasons beyond the company's control, a non-domestic point below 50,000 Smc a year moves to the supplier of last resort; in other cases the default service is activated.
Checking metering, rates and prices is part of the energy and gas invoice audit service by IPGS ENERGY. Request a review.
Sources
- ARERA — Glossary of the natural gas bill, in force since 1 July 2025 (accessed 10 October 2026)
- ARERA — Resolution 315/2024/R/com, "La bolletta dei clienti finali di energia" (accessed 10 October 2026)
- ARERA — Standard offers for end customers, PLACET (accessed 10 October 2026)
- Customs and Monopolies Agency — National excise rates (accessed 10 October 2026)
- Customs and Monopolies Agency — Circular no. 32/2025 (accessed 10 October 2026)
- Normattiva — Decree-Law no. 356 of 1 October 2001, article 4 (accessed 10 October 2026)
- Italian Revenue Agency — Circular no. 17/E of 3 December 2021 (accessed 10 October 2026)
- CSEA — Circular no. 5/2026/GAS, gas-intensive companies (accessed 10 October 2026)
Informational content by IPGS ENERGY. Information is reviewed as of the stated update date and does not replace a contractual, tax or regulatory assessment specific to an individual business.
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