Which greenhouse gases does the UK CBAM count for fertilisers?
CO2 and nitrous oxide. HMRC's UK CBAM guidance counts CO2 in every sector, N2O for fertilisers and PFCs for aluminium, matching the UK ETS. N2O converts at 265 tCO2e per tonne. Process N2O from nitric acid must be measured by continuous emission monitoring, and it carries into nitrates made from that acid.
What is counted
- CO2 from fuel burned in stationary plant, not vehicles.
- CO2 and N2O from the process, in particular N2O from catalytic oxidation of ammonia or from NOx/N2O abatement units.
- CO2 from making steam or other heat consumed in the process, on site or bought in.
- CO2 from emissions control, such as soda ash used in flue gas cleaning.
- CO2 used to make urea counts as emitted at your plant.
What is not
- N2O from burning fuel.
- Electricity use.
How N2O must be monitored
Process N2O is relevant only in nitric acid production, and must be monitored with a continuous emission monitoring system at a suitable point. For flue gas flow, HMRC prefers the mass balance method over flow measurement. Where nitric acid or the nitrates made from it are used as a precursor, the N2O is part of the embodied emissions.
Nitric acid into ammonium nitrate
- Process N2O measured in the year: 18 t, so 18 x 265 = 4,770 tCO2e.
- CO2 from natural gas and steam in the process: 21,000 tCO2.
- Total: 21,000 + 4,770 = 25,770 tCO2e before dividing by production.
- Cut process N2O by 6 t with better abatement and the total falls by 1,590 tCO2e.
Example figures.
What Senseible does here
Senseible reads natural gas, steam and other fuel invoices into the CO2 side; N2O comes from your stack monitor. We build the figure from your records and check every figure in-house; for the UK it must then be verified by a verifier accredited for UK CBAM. Have your own verifier? Send it to them.
Sources: HMRC, UK CBAM monitoring, reporting and verification technical guidance (October 2026), HMRC, Carbon Border Adjustment Mechanism (CBAM): Policy summary (updated 2 November 2026)
Last reviewed 2026-11-03.