Carbon Tax in Ireland: Revenue Compliance for Businesses and Business Fuel

Carbon tax in Ireland is not a single tax with one return. Revenue collects it through three routes: a carbon component inside Mineral Oil Tax on liquid fuels and vehicle gas, Natural Gas Carbon Tax (NGCT) on natural gas supplied to consumers, and Solid Fuel Carbon Tax (SFCT) on coal and peat. Businesses that only buy fuel will usually see carbon tax as part of the price they pay, while suppliers, importers and authorised warehousekeepers have registration and filing duties. This guide explains how Revenue structures these taxes and who accounts for them. It gives no rates or amounts, because they change; check Revenue's rate pages on the day.

Three routes, one idea

Revenue's pages describe the same principle in each case: the charge is proportionate to the carbon dioxide released when the fuel is burned. The overview pages for NGCT (published 6 August 2026) and SFCT (published 14 August 2026) both say the rate of tax is proportionate to the amount of CO2 emitted on combustion. Both are administered by Revenue as part of its excise and energy taxes work, alongside excise duty generally. Our guide to excise duty authorisation and returns covers the wider excise framework.

Carbon tax on liquid fuels and vehicle gas

Revenue's Mineral Oil Tax page (published 29 September 2026) says Mineral Oil Tax applies to liquid fuels and to vehicle gas. Its rates have two parts: a non-carbon component and a carbon component. Revenue says the carbon component is usually called carbon tax and is based on the CO2 emissions released when a fuel is burned. The products listed include petrol, kerosene, fuel oil and marked gas oil, liquefied petroleum gas, substitute fuels and vehicle gas.

Revenue's manual on accounting for Mineral Oil Tax (last reviewed August 2026) describes the "Carbon Charge" as part of the overall Mineral Oil Tax rate, not an extra charge. It is calculated on CO2 emissions per fuel type using Environmental Protection Agency emission factors. The manual explains who is liable:

• Authorised warehousekeepers hold and dispatch duty-suspended oil and are responsible for the duty on it, including providing financial security.
• Registered consignees receive duty-suspended consignments and account for them.
• Vehicle gas suppliers are liable when gas is supplied to a vehicle and must be registered with Revenue.

The manual states that oil distributors and forecourt retailers do not need Mineral Oil Tax registration. This is our reading, not a Revenue statement: a business that buys fuel from a supplier is unlikely to account for Mineral Oil Tax itself, but check with the supplier and Revenue's guidance.

Natural gas carbon tax

Revenue says NGCT was introduced on 1 May 2010 and taxes natural gas supplied to consumers. It applies to all natural gas supplies regardless of the storage or transportation form used, including LNG and CNG. Since 1 January 2017, natural gas used as fuel in a motor vehicle has fallen under Mineral Oil Tax instead.

The NGCT Compliance Procedures Manual (last updated August 2026) describes NGCT as an excise duty on natural gas supplied to consumers, for which the supplier is accountable and liable to pay. Self-supply for a supplier's own use is also taxable. Key points from the manual:

• Suppliers must register on Form NGCT Reg before they start supplying gas. A supplier not established in the State must appoint a competent person in the State to account for the tax.
• Suppliers file a return and pay for each bi-monthly period by the last day of the following month, and nil returns are required where no tax is due.
• Consumers can be liable for any shortfall caused by false or misleading information they gave the supplier.
• Records must be kept for at least six years from the last entry.

The manual does not address VAT, so check separate Revenue guidance for VAT treatment of energy supplies.

Solid fuel carbon tax

According to Revenue's SFCT overview, the tax applies to coal, peat briquettes, milled peat and other peat supplied in the State. Liability arises at the time the fuel is first supplied in the State and falls on the supplier. An individual who buys solid fuel abroad and brings it into the State for their own private use, accompanying it into the State, has no liability, but if they supply it to another person they become the supplier for that supply and must register. Wood with no solid fuel component is not liable.

Revenue's SFCT Compliance Procedures Manual (last updated August 2026) adds that peat extractors who sell their peat are liable, supplying fuel to yourself counts as a first supply, and importers and manufacturers normally must register. Wholesalers and retailers must register only if they source fuel from outside the State; traders who buy all their fuel from in-State suppliers generally do not need to register because the supplier has already paid the tax. SFCT is self-assessed, with two-monthly returns due by the last day of the following month and a nil return where there are no supplies.

Reliefs and declarations

Both manuals describe reliefs for particular uses. For NGCT, full relief applies to gas shown to be used solely for electricity generation, chemical reduction, electrolytic or metallurgical processes, diplomatic arrangements, or certain heat and power cogeneration. Greenhouse gas emissions permit holders get partial relief. For SFCT, Revenue describes full relief for fuel used solely for electricity generation (excluding combined heat and power), peat in permitted greenhouse gas installations, and certain industrial uses, with partial relief for coal used in permitted installations and for qualifying biomass products.

Relief can generally be given at source if the supplier holds a valid consumer declaration in advance; otherwise the consumer must claim repayment from Revenue. For the Mineral Oil Tax carbon charge, the manual says relief from the Carbon Charge alone may apply, for example for biofuel content or oil used in installations covered by a greenhouse gas emissions permit. Whether a particular business qualifies depends on the detailed conditions on Revenue's reliefs pages, so this guide does not attempt to confirm eligibility.

Compliance risks Revenue highlights

The SFCT manual lists the main compliance risks as non-registration, late or missing returns, inaccurate returns, tax-free supplies made without valid declarations, and use of relieved fuel for non-qualifying purposes. It says branches should incorporate a Whole Case Management approach where possible because SFCT and VAT are closely linked, and that incorrect information can lead to offences, tax-geared penalties and assessments. The NGCT manual says directors and officers can be personally liable where they knew of or consented to an offence. Interest applies to late payment. Overpaid duty can be reclaimed only within a limited period set out in the manual, so do not leave repayment claims to accumulate.

Where carbon tax meets customs and VAT

If your business imports fuel or solid fuel, the customs side and the carbon tax side are separate obligations. Our guide to customs and EORI for Irish businesses explains the import registration framework, and our VAT returns and record keeping guide covers filing and records. Revenue's carbon tax pages are about the tax on the fuel itself; they do not replace the customs or VAT rules.

A practical approach for businesses

These are our suggestions, not Revenue requirements.

• Our suggestion: work out whether your business is a consumer, a retailer or a supplier of each fuel. Only suppliers, importers, warehousekeepers and similar roles file carbon tax returns.
• Our suggestion: if you buy fuel for a process that Revenue lists as relieved, ask your supplier what declaration it needs and keep a copy.
• Our suggestion: review fuel invoices once a year to confirm relief was applied at source where you expected it.
• Our suggestion: keep supply, stock and declaration records in one place for the period Revenue's manuals specify.

Learnsignal's offices are off Baggot Street in Dublin, and we offer in-person training from there. For current details, see our CPD pages.

Frequently asked questions

Is carbon tax charged on petrol and diesel?

Revenue says Mineral Oil Tax rates on liquid fuels have a non-carbon component and a carbon component, and that the carbon component is usually called carbon tax. Revenue's manual says the Carbon Charge is part of the overall rate, not an extra charge.

Does my business have to register for carbon tax?

Only if you fall within the supplier roles in Revenue's manuals, for example a natural gas supplier, a first supplier of solid fuel, an importer or manufacturer of solid fuel, or an authorised warehousekeeper. Forecourt retailers and oil distributors do not need Mineral Oil Tax registration, according to the manual.

Can a business get relief from carbon tax?

Revenue's manuals describe reliefs for specified uses, such as electricity generation and certain industrial processes, and for greenhouse gas emissions permit holders. Relief usually depends on a declaration or a repayment claim.

How long should carbon tax records be kept?

Revenue's NGCT, SFCT and Mineral Oil Tax manuals each refer to a six-year period from the date of the last entry. The Mineral Oil Tax manual adds that Revenue may advise a different period in particular cases. Check the manual for your tax head on the day.

Where can I find current rates?

Revenue publishes rates on its NGCT, SFCT and Mineral Oil Tax pages, and they change. Always use the current page rather than a figure from an article.

Carbon tax is easy to overlook until a relief or registration question arises, so decide your role for each fuel and keep the records that go with it.