What does a CBAM calculation for steam reforming hydrogen look like?
The Commission's example: a steam reformer burning 190,000 tonnes of natural gas and exporting 800 TJ of heat emits 461,765 t CO2 net, over 55,000 t of hydrogen. That is 8.396 t CO2 per tonne. With 2028 free allocation of 4.580, importing 100 tonnes leaves 381.6 certificates.
What is monitored
One production process. The only source stream is natural gas, used as feedstock and fuel. Hydrogen is a simple good, so there are no precursors, and only direct emissions count. Heat exported to the rest of the plant or a district network is subtracted. For heat of unknown origin the default is natural gas at 90% boiler efficiency, which is 62.3 t CO2 per TJ.
Free allocation and the import
Hydrogen has one benchmark whatever the route: 5.089 t CO2 per tonne of hydrogen. The example assumes year 2028, CSCF 1.00 and CBAM factor 90%. Captured CO2 sent to storage could also be deducted, if the receiving site monitors under CBAM.
Steam reforming, hydrogen, import in 2028 (Commission's example)
- Natural gas: 190,000 t x 48 GJ/t = 9,120 TJ; x 56.1 t CO2/TJ = 511,632 t CO2
- Heat export: 800 TJ x 62.3 t CO2/TJ = about 49,867 t CO2, subtracted
- Total direct emissions: 461,765 t CO2
- Hydrogen made: 55,000 t, so specific embedded emissions = 8.396 t CO2 per t
- Free allocation: 5.089 x 0.90 x 1.00 = 4.580 t CO2 per t
- Import of 100 t: 839.6 t CO2 less 458.0 t CO2 = 381.6 certificates, before any carbon price deduction
Figures are the Commission's own worked example in Guidance No. 5b, not a real plant. Your numbers will differ.
What Senseible does here
Senseible reads natural gas invoices into dated, fingerprinted quantities, which is the largest input line in a reformer's calculation. The heat export, free allocation and import steps are done in the Commission's template.
Sources: European Commission, CBAM Guidance No. 5b, hydrogen (14 August 2026), sections 3.1 and 4
Last reviewed 2026-10-25.