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How do you calculate CBAM embedded emissions for ammonium nitrate?

Fertilisers carry a two-level precursor chain and a gas 265 times stronger than CO2. Most of the result is decided upstream of the plant that ships the product.

Julian R. Sterling · from The CBAM Compliance Handbook

CBAM embedded emissions of ammonium nitrate are the plant's own direct and indirect emissions plus each precursor consumed times its specific embedded emissions: ammonia directly, and nitric acid, which itself carries ammonia and the nitrous oxide of its own process, converted at a global warming potential of 265. An illustrative plant gives 1.55 tonnes of CO2e per tonne of ammonium nitrate, 27.0 per cent of it from nitrous oxide alone.

Worked in full in The CBAM Compliance Handbook by Julian R. Sterling, with every figure reproduced in a free workbook.See the book on Amazon →

The assumptions

Fertilisers are one of the two CBAM sectors, with cement, where indirect emissions from electricity count alongside direct emissions. The precursor chain has two levels: ammonia goes into nitric acid, and both go into ammonium nitrate. Every figure below is illustrative; a real declaration uses the installation's monitored data or the applicable default values.

Illustrative plant, per tonne of output

Input	Value
Ammonia, specific embedded emissions (direct plus indirect)	2.40 tCO2e/t
Nitric acid plant: N2O emitted	2.0 kg/t HNO3
Nitric acid plant: other direct CO2	0.010 t/t
Nitric acid plant: electricity	0.02 MWh/t
Nitric acid plant: ammonia consumed	0.285 t/t HNO3
Ammonium nitrate plant: direct emissions	0.040 t/t
Ammonium nitrate plant: electricity	0.050 MWh/t
Ammonium nitrate plant: ammonia consumed	0.215 t/t AN
Ammonium nitrate plant: nitric acid consumed	0.790 t/t AN
Grid emission factor	0.40 tCO2/MWh
Global warming potential of N2O	265

The precursor quantities can be checked against chemistry. NH3 + HNO3 gives NH4NO3, so a tonne of ammonium nitrate contains 17.031 / 80.043 = 0.2128 tonnes of ammonia and 63.013 / 80.043 = 0.7872 tonnes of nitric acid; making a tonne of nitric acid takes at least 17.031 / 63.013 = 0.2703 tonnes of ammonia. Measured consumption sits slightly above those floors because of losses. A supplier figure below them is a data error.

Step 1: specific embedded emissions of nitric acid

Two kilograms of nitrous oxide weigh almost nothing and count for more than half a tonne of CO2e. That is why the abatement catalyst in a nitric acid plant is the single most important line in a fertiliser supplier's data.

Step 2: specific embedded emissions of ammonium nitrate

Where the emissions come from is more useful than the total. Ammonia, counted once through each route, is 0.4401 tonnes per tonne of product and 68.2 per cent of the result. Nitrous oxide is 0.419 tonnes, 27.0 per cent. The plant's own direct and indirect emissions, the only part the ammonium nitrate site controls, are 0.060. Electricity in total, across both stages, is 0.0263. On 100,000 tonnes of imports the total is 154,928 tonnes of CO2e.

What if the nitric acid plant has no abatement?

Specific embedded emissions by N2O emission level, tCO2e per tonne

N2O, kg/t HNO3	N2O as CO2e	SEE nitric acid	SEE ammonium nitrate	Change
0.5	0.1325	0.8345	1.2353	-0.3140
2.0	0.5300	1.2320	1.5493	0.0000
6.0	1.5900	2.2920	2.3867	+0.8374

An unabated plant at around 6 kilograms of N2O a tonne nearly doubles the figure against a well-abated one, from 1.24 to 2.39. The ammonia figure matters as much: at 1.80 tonnes a tonne the product comes out at 1.2852, at 3.00 it is 1.8134. Those two inputs, both upstream of the ammonium nitrate plant, decide the declaration.

The same precursor logic carries through to downstream products. A calcium ammonium nitrate or a compound fertiliser takes ammonium nitrate as its precursor, and the chain gains a third level. Track mass in tonnes of product on the basis the default values use, and say which basis the supplier reported.

The common mistakes

• N2O in tonnes of gas, not CO2e. Adding 0.0016 tonnes of N2O per tonne of product instead of 0.419 gives 1.1322 and understates the result by 26.9 per cent.
• Counting the ammonia in nitric acid twice. The nitric acid SEE already includes its ammonia. Adding that ammonia again at the ammonium nitrate stage gives 2.0896, 34.9 per cent too high, and the importer pays for it.
• Dropping indirect emissions. Correct for steel and aluminium, wrong for fertilisers. Here the amount is small, but on a coal-heavy grid it is not.

The same structure for steel, where only direct emissions count, is in how to calculate CBAM embedded emissions for a steel product, and for the other sector with indirect emissions in CBAM embedded emissions for cement.

Takeaway

• SEE = direct + indirect + Σ precursor consumed × precursor SEE, applied stage by stage.
• Nitric acid: N2O × 265 plus its ammonia; here 1.2320 tCO2e a tonne.
• Ammonium nitrate: 1.5493 tCO2e a tonne, 68.2 per cent ammonia and 27.0 per cent N2O.
• Check supplier precursor quantities against the stoichiometric floors of 0.2128, 0.7872 and 0.2703.

The supplier data request, the default value comparison and the obligation built line by line are in the free working documents and workbook for this book.

Questions readers ask

Do indirect emissions count for fertilisers under CBAM?

Yes. In the definitive period, iron and steel, aluminium and hydrogen are assessed on direct emissions only, while cement and fertilisers include indirect emissions from electricity. In the illustrative ammonium nitrate case electricity adds 0.0263 tCO2e per tonne across both production stages, small on a 0.40 grid factor but larger where power is coal-based.

How is N2O from nitric acid converted for CBAM?

Multiply the mass of N2O by its global warming potential of 265. A nitric acid plant emitting 2.0 kg of N2O per tonne adds 0.530 tCO2e per tonne of acid; an unabated plant at 6.0 kg adds 1.5900. Carried through to ammonium nitrate, that moves the product's embedded emissions from 1.5493 to 2.3867 tCO2e a tonne.

How much ammonia is in a tonne of ammonium nitrate?

By molar mass, 0.2128 tonnes of ammonia combined directly plus 0.7872 tonnes of nitric acid, which itself needs at least 0.2703 tonnes of ammonia a tonne. Measured consumption runs slightly higher; in the illustrative plant total ammonia is 0.4401 tonnes per tonne of product and accounts for 68.2 per cent of its embedded emissions.

Also on this site

• How do you calculate CBAM embedded emissions for a steel product?Process emissions plus precursor consumed times its SEE, over output. 2,400 plus 21,500 t of wire rod at 1.90, over 20,000 t, gives 2.1625 tCO2e a tonne.
• How do you calculate CBAM embedded emissions for cement?Grinding emissions, direct and indirect, plus clinker consumed times clinker SEE, over cement output. An illustrative plant gives 0.7226 tCO2e a tonne.
• How do you calculate CBAM embedded emissions for aluminium?Direct emissions only: extrusion process plus billet consumed times its SEE, over output. An illustrative profile gives 2.1925 tCO2e a tonne, coal or hydro.
• How much will CBAM cost per tonne of steel from 2026 to 2034?With a 1.37 benchmark, 2.0 tCO2 a tonne and 80 euro certificates, CBAM costs 53.14 euros a tonne of steel in 2026, 103.56 in 2030 and 160.00 in 2034.
• Is it worth staying under the CBAM 50 tonne threshold?Crossing 50 tonnes by 5 brings all 55 into CBAM. In 2026 the certificates cost 210 euros; the fixed compliance cost, 15,000 illustrative, is what makes the cliff.
• How is the CBAM certificate price calculated for 2026 imports?A quarterly average of EU ETS auction prices, applied to each quarter's imports. 360 certificates at 75.36, 75.28, 82.32 and 80.00 cost 28,060.56 euros.

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