Hydrogen counts direct emissions only, so a reformer carries nearly nine tonnes a tonne and an electrolyser on a coal grid carries none.
For hydrogen, CBAM specific embedded emissions are the installation's attributed direct emissions divided by the tonnes of hydrogen produced; the electricity consumed is not counted. For an illustrative steam methane reformer making 50,000 tonnes a year, 8,100 TJ of natural gas feed and fuel at 56.1 tCO2 per TJ give 454,410 tCO2, the steam it exports takes 9,350 of them away, and the answer is 8.9012 tCO2 a tonne. At an illustrative 80 euros a certificate that is 0.71 a kilogram once free allocation has gone.
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 →
Hydrogen is a CBAM good and, like iron and steel and aluminium, one for which only direct emissions count in the definitive period. It has no relevant precursors, so the whole answer comes from the installation's own emissions. The reformer below is fictional and its figures illustrative; the gas emission factor is the standard one for natural gas, and a real plant applies its own analysed factor where its monitoring plan requires one.
| Input | Value |
|---|---|
| Hydrogen produced, tonnes | 50,000 |
| Natural gas as feedstock, TJ | 5,900 |
| Natural gas as fuel, TJ | 2,200 |
| Emission factor, tCO2 per TJ; oxidation factor | 56.1; 1 |
| Steam exported to a neighbouring plant, TJ | 150 |
| Hydrogen imported into the EU by one customer, tonnes | 2,000 |
A reformer burns gas to heat the reformer tubes and also feeds gas into them, where the methane is split into hydrogen and CO2. Both streams end up as CO2 leaving the site, so both are source streams, each on the standard method: activity data times emission factor times oxidation factor.
Feed = 5,900 × 56.1 = 330,990 tCO2
Fuel = 2,200 × 56.1 = 123,420 tCO2
Direct emissions = 454,410 tCO2, 72.8 per cent of it from the feed
The plant uses 162 GJ of gas a tonne of hydrogen. That intensity, not the emission factor, is what differs from one reformer to the next.
The CBAM attribution rules move the emissions of measurable heat with the heat. Steam sold to a neighbour takes its share of emissions out of the hydrogen. Where the installation has not determined its own heat emission factor, the rules value it at natural gas over a reference boiler efficiency of 90 per cent.
Heat emission factor = 56.1 / 90% = 62.33 tCO2 per TJ
Exported steam = 150 × 62.33 = 9,350 tCO2
Attributed emissions = 454,410 − 9,350 = 445,060 tCO2
SEE = 445,060 / 50,000 = 8.9012 tCO2 a tonne
Excel: =(SUM(GasTJ)*EF*OxF-SteamTJ*EF/0.9)/H2Tonnes
The customer importing 2,000 tonnes declares 17,802 tCO2. At 80.00 a certificate, the full exposure is 1,424,192 a year, 712.10 a tonne or 0.71 a kilogram, before the free-allocation adjustment of the early years. The way that adjustment phases out is shown for steel in how much CBAM will cost per tonne of steel from 2026 to 2034; the arithmetic is the same.
Because almost the whole answer is gas times a factor, the gas meter is the measurement that matters. A 1 per cent error in the metered gas moves the specific embedded emissions by 0.0909 a tonne, 181.8 tCO2 on the customer's 2,000 tonnes and 14,541 of full exposure a year. A verifier will start with the fiscal meters on the feed and fuel lines, the split between them, and the analysed carbon content if the plant uses its own factor; the importer should ask the supplier which of these were verified before relying on the figure.
| Variant | SEE, tCO2/t | Declared on 2,000 t |
|---|---|---|
| Efficient reformer, 150 GJ a tonne | 8.2280 | 16,456 |
| Base case, 162 GJ a tonne | 8.9012 | 17,802 |
| Older reformer, 175 GJ a tonne | 9.6305 | 19,261 |
| Base case, 60% of feed CO2 permanently stored | 4.9293 | 9,859 |
| Electrolyser on a grid at 0.60 tCO2/MWh | 0 | 0 |
The last line is the one that surprises. An electrolyser using 52 MWh a tonne on a grid at 0.60 is responsible for 31.2 tCO2 a tonne, three and a half times the reformer, and declares nothing, because the electricity is indirect and hydrogen counts direct emissions only. A buyer reading a CBAM declaration as a carbon footprint will get electrolytic hydrogen exactly wrong.
Hydrogen often arrives inside another CBAM good. A fertiliser plant that makes its own hydrogen for ammonia does not report hydrogen at all; the reformer's emissions flow into the ammonia, as in CBAM embedded emissions for ammonium nitrate. Imported on its own, hydrogen is also outside the 50-tonne de minimis threshold, so even a small importer declares it, as explained in does crossing the CBAM 50-tonne threshold pay.
The supplier data request and the default-or-actual log, year by year, are among the working documents in the free files for this book.
No. Hydrogen is one of the goods for which only direct emissions count in the definitive period, with iron and steel and aluminium. An electrolyser using an illustrative 52 MWh a tonne on a grid at 0.60 tCO2 per MWh is responsible for 31.2 tCO2 a tonne, and declares none of it, while a gas reformer declares 8.9012.
Only where it is permanently stored under the conditions the monitoring rules set; confirm against the consolidated text. Storing 60 per cent of the process CO2 here, 198,594 tonnes, would take the figure from 8.9012 to 4.9293. CO2 sold for drinks or greenhouses is released later and cannot be subtracted: deducting 100,000 tonnes of it would under-declare by 22.5 per cent.
Emissions attributed to measurable heat leaving the installation are subtracted from the hydrogen's emissions. Where the heat's own emission factor is not determined, it is valued at natural gas over a reference efficiency of 90 per cent, 62.33 tCO2 per TJ. Here 150 TJ of steam carries 9,350 tCO2 out, 2.1 per cent of the total.
This article is one calculation from The CBAM Compliance Handbook. The book takes the same case from first principles to the decision, chapter by chapter, and every figure it prints is a live formula in the free companion workbooks.
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