UK CBAM rate and carbon price relief: SI 2026/809 explained

SI 2026/809 does not tell you the UK CBAM rate you will pay. It provides the legal method for calculating that rate and for determining carbon price reliefcarbon price reliefA reduction of UK CBAM liability for eligible embodied emissions already subject to a qualifying overseas carbon price, capped at the UK liability.. It is a calculation framework, not a table of ready-to-use rates.

Several notices and operational inputs were still outstanding at the research cutoff. You can map the data flow now, but you cannot fill the gaps with assumed rates, standards or exchange rules.

How the quarterly CBAM rate is built

The rate starts from an average carbon price. For a quarter, the average UK ETS price is the mean of the auction clearing prices in the preceding quarter. If no allowances were sold in that quarter, the method looks back to the most recent quarter in which allowances were sold.

The free-allocation adjustmentFree-allocation adjustmentReduction of certificates to surrender: FAA_g = SEFA_g,y × M_g; zero for electricity. Actuals → Column A path (Eq. 2–5, recursive for precursors); defaults → Column B path (Eq. 6). uses the relevant scheme-year factor in Article 16(14) of Commission Delegated Regulation (EU) 2019/331, as assimilated and amended by SI 2026/278.

Keep the wording "assimilated and amended" in any summary you write. Both the assimilation and the amendment are part of the reference.

The instrument sets the method, not a table of numerical sector rates. Take the rates from the applicable official source at the time you need them.

Who can claim carbon price relief

Relief may be available where the good was made or processed at an installation in a qualifying carbon-pricing scheme. The verification conditions must also be met.

Participation can include a voluntary participant below a scheme threshold, provided the scheme itself satisfies the mandatory-coverage criteria.

A qualifying scheme must:

• be publicly administered;
• require the relevant class of installations to participate;
• impose a direct or qualifying indirect emissions cost;
• publish its rules, scope and headline price.

For an indirect fuel-price mechanism, a Treasury notice sets the emissions-factor sources and methods. That notice was an operational dependency at the cutoff.

Verification: who may sign, and what they verify

Verified information includes total relevant installation emissions and the emissions subject to each scheme element. It also includes monetary supportmonetary supportFinancial support or compensation that the UK CPR method requires to be reflected when determining the effective carbon price. and, where relevant, indirect-scheme emissions factors.

The verifierVerifierAccredited independent third party confirming the SEE is free of material misstatement; any EU or third-country legal person; only values in a verification report count for actuals. Importers receiving "verification reports" from third part must meet the accreditation requirements named in an HMRC notice. The verifier must also hold accreditation from a full member of Global Accreditation Cooperation Incorporated.

The verifier must also be independent of the installation, the importer and the relevant authorities. Test that independence early, before you commission verification work.

The final instrument does not hard-code specific ISO standards. If guidance or a notice names a standard, record it with that source status, and do not present it as words of the SI.

The relief calculation runs in 5 steps

The effective carbon priceeffective carbon priceThe verified net carbon price recognized under the UK CPR method after required adjustments. follows 5 statutory steps:

1. Identify relevant emissions.
2. Identify those subject to scheme elements.
3. Price the elements.
4. Divide by total emissions.
5. Deduct monetary support per tonne of carbon-dioxide equivalent.

Each qualifying precursorPrecursorUpstream CBAM good consumed as input to a complex-good process; listed per route; quantities always monitored per Annex II pt E. needs its own effective-price calculation. Carbon price relief is then the effective price multiplied by eligible embodied emissionseligible embodied emissionsThe portion of a good's embodied emissions that qualifies for UK carbon price relief.. It cannot exceed the CBAM liability.

What it means for importers

You can build the data trail for relief now, but not the final numbers. A legally defined method is not yet a fully operable workflow.

What to do

• Map each installation, each carbon-pricing scheme element and each precursor. Then identify who can supply the verified emissions figures, the monetary support figures and the scheme-participation evidence.
• Keep three calculations separate: the rate calculation, the effective-price calculation and the final relief calculation. Running them as one step hides which input is still missing.
• Record two gaps in the SI now: it supplies no exchange-rate period and no rounding convention. It delegates foreign-currency procedure to an HMRC notice.
• Retain scheme-eligibility evidence, the verification form and the calculation records for 6 years from the day after the accounting-period end.
• Before you rely on the rules, recheck Commons approval and fetch every relevant Treasury or HMRC notice.

Stuck on this in your own import data? Write to us and we will look at it with you.

This article explains the as-made text of SI 2026/809. Recheck parliamentary approval, notices, rates and operational forms before you make a claim. It is not legal, tax or customs advice.