How to read a business’s energy invoice

The four items, and which one depends on the contract

ARERA, Italy’s energy authority, divides the costs into items that are the same for all suppliers:

• Electricity sales costs (in the ARERA glossary also “energy commodity costs”): the purchase of energy, dispatching, that is the service that keeps supply and demand in balance at every moment, and retail. It is the only item that depends on the contract. For ARERA the energy price also includes network losses.
• Network costs (in the glossary “for transport and meter management”): transmission on the national grid, local distribution and metering, that is meter reading and data management. The tariffs are set by ARERA, the same throughout the country.
• General system charges: costs of general interest to the electricity system, paid by all customers.
• Taxes: excise duty and VAT.

Alongside the summary invoice there is a second document, the itemised details: each component with its quantity and unit price, divided into fixed charge, consumption charge, power charge and, where needed, reactive energy. This format is set by ARERA resolution 315/2024/R/com, in force from 1 July 2025 for low-voltage supplies and for gas up to 200,000 Smc (standard cubic metres) a year. For gas the items are the same; the taxes also include the regional surcharge.

System charges: ASOS and ARIM

Since 1 January 2018 the charges have been two components. ASOS covers support for renewable sources and for CIP 6/92 cogeneration. ARIM covers the remaining charges: among others, nuclear decommissioning, relief for the railway sector, system research, the electricity bonus and energy efficiency. ARERA updates the rates every quarter according to requirements: those in force from 1 October 2026 come from resolution 343/2026/R/com.

ASOS is paid differently if the business is one of those with high electricity consumption, according to its relief class: this is the subject of the guide to energy-intensive companies.

Taxes: excise duty and VAT

The excise duty on electricity is set by law: the Consolidated Excise Act, Legislative Decree 504 of 1995, with the rates in its Annex I. It is paid by whoever invoices you for the energy, who then charges it to you; it is administered by the Customs and Monopolies Agency. Outside homes the rate goes by monthly consumption bands: 0.0125 euro per kWh on the first 200,000 kWh of the month, 0.0075 euro for the following kWh up to 1,200,000. If the month exceeds 1,200,000 kWh, beyond the first 200,000 a fixed sum of 4,820 euro a month is paid.

Some uses are not subject to excise duty: for example energy used mainly for chemical reduction and in electrolytic and metallurgical processes, or in mineralogical processes.

For gas, since 1 January 2026 excise duty has distinguished domestic from non-domestic uses, instead of civil and industrial. The non-domestic rate is the more favourable, but a business’s offices located away from the site count as domestic use.

VAT is 22%. It is 10% on electricity and gas used by extractive, agricultural and manufacturing businesses, including printing and publishing companies.

Power and reactive energy, in medium voltage

• Power. Where there is no limiter, the committed power on which the power charge is paid is the maximum value drawn in the month, measured as the average of the highest quarter-hour: a single quarter-hour peak is enough to set the month’s power.
• Reactive energy. It is energy ancillary to the operation of equipment, which produces no useful effect and increases network losses; it is measured in kvarh. For non-domestic customers in medium voltage, and in low voltage above 16.5 kW of available power, the distributor applies charges: in bands F1 and F2 on reactive energy drawn above 33% of active energy, in band F3 on reactive energy fed into the grid. It is reduced with power factor correction, that is with capacitors. In low voltage the invoice must show every month the ratio between reactive and active energy and the power factor.

Resolution 315/2024/R/com on the invoice format does not apply to medium voltage; network and charges remain items set by ARERA.

Where errors arise: the checks to make

• Estimated or measured consumption. The meter is not read by the supplier: the actual reading is the distributor’s, which passes it on to the supplier. Without readings, the supplier invoices estimated consumption and recalculates it later. A series of estimates, or a recalculation that doesn’t add up, is checked against the distributor’s measurements.
• Excise duty and VAT. The bands applied to the month’s consumption, a use not subject to excise duty treated as taxable, gas for a site at the domestic rate, VAT at 22% where 10% applies.
• The price against the contract. The offer box shows the price formula and the values of its elements in the period, for example the PUN, the single national price: they are compared with the signed contract, with its start and expiry dates.
• Power and reactive energy, compared with the month’s measurements.

How we do it: Calibra

We recalculate every electricity and gas invoice item by item with Calibra, our software: sales, network, charges, excise duties and VAT, each with the regulation alongside. Across twelve invoices for the same supply point we tell the systematic error, which repeats, from the noise of a single invoice. Calibra is part of the service for consumers, with the paperwork for excise duty exemptions and relief. Why we write “invoice” is explained in the FAQ.