CBAM Hydrogen Calculation: How to Compute Embedded Carbon for Grey, Blue, and Green Hydrogen
CBAM hydrogen calculation depends entirely on the production route. Grey hydrogen from steam methane reforming has actual embedded emissions of 9–11 tCO2/t H2. Blue hydrogen (SMR with CCS) reduces this by 60–95% depending on capture rate. Green hydrogen from electrolytic production powered by renewables has near-zero direct embedded emissions but the indirect emissions from the electricity used are critical and depend on renewable matching rules.
CBAM Hydrogen Calculation by Production Route
| Production route | Direct emissions | Indirect electricity emissions | Total embedded |
|---|---|---|---|
| Grey (SMR, natural gas) | ~9.0 tCO2e/t | ~1.0 tCO2e/t | ~10.0 tCO2e/t |
| Grey (gasification, coal) | ~18.0 tCO2e/t | ~2.0 tCO2e/t | ~20.0 tCO2e/t |
| Blue (SMR + CCS, 90% capture) | ~1.0 tCO2e/t | ~1.5 tCO2e/t (CCS energy) | ~2.5 tCO2e/t |
| Green (electrolytic, renewable) | ~0 tCO2e/t | 0–0.3 tCO2e/t (grid factor) | 0–0.3 tCO2e/t |
| Pink (electrolytic, nuclear) | ~0 tCO2e/t | ~0.05 tCO2e/t | ~0.05 tCO2e/t |
Hydrogen is the most route-sensitive of any CBAM-covered commodity. The same physical product (H2 molecule) has 200× difference in embedded emissions between routes.
Hourly Matching for Renewable Electrolytic Hydrogen
For green hydrogen to claim near-zero embedded emissions, the electricity used must be matched to renewable generation. EU rules (RED III, RFNBO Delegated Act) require hourly temporal correlation between renewable generation and electrolyser consumption — you cannot run an electrolyser at night on grid power and claim it as green based on a daytime PPA.
For CBAM specifically, the verifier needs to see the matching mechanism, the renewable PPA contracts, and the temporal correlation evidence. This is operationally complex but critical — without it, the electrolytic hydrogen reverts to the grid emission factor for its location, which can push embedded emissions into 5–15 tCO2e/t territory.
Blue Hydrogen and CCS Capture Rate
Blue hydrogen embedded emissions depend critically on the CCS capture rate:
- 60% capture rate: ~4 tCO2e/t H2 — barely below the 5.28 default
- 90% capture rate: ~2.5 tCO2e/t H2
- 95% capture rate (best-in-class): ~1.5 tCO2e/t H2
Capture rate must be measured and verified continuously. Project announcements claiming 90%+ capture often deliver 70–85% in operation. The CBAM verifier will look for actual measured capture rates, not nameplate.
Replacing the Hydrogen Default
The 5.28 default is roughly the global production weighted average across grey (dominant), blue (small share), and green (small share). For producers operating outside the grey-dominated cluster, documenting actuals is straightforward and the saving is substantial:
- Green hydrogen actual at 0.3 tCO2e/t: saving of EUR 324/t at EUR 65 ETS
- Blue hydrogen actual at 2.5 tCO2e/t: saving of EUR 181/t
For a 100,000 t/year hydrogen plant, the difference is EUR 18–32 million annually. Store the verified record.
Frequently Asked Questions
What CN code does CBAM cover for hydrogen?
Hydrogen is covered under CN code 2804 in CBAM Annex I.
What is the CBAM default value for hydrogen?
Approximately 5.28 tCO2e per tonne, reflecting the global production weighted average dominated by grey hydrogen from SMR.
How much does grey hydrogen actually emit?
SMR-based grey hydrogen from natural gas: ~10 tCO2e/t. Gasification-based grey hydrogen from coal: ~20 tCO2e/t. Both are above the 5.28 default — meaning grey hydrogen producers may face higher than default exposure if their actuals are documented honestly.
Is green hydrogen automatically zero-emission for CBAM?
No. Green hydrogen claims require hourly temporal matching of electrolyser consumption to renewable generation, plus verified PPA evidence. Without that, the electrolytic hydrogen reverts to the grid emission factor at the production location.
What capture rate does blue hydrogen need to beat the default?
Approximately 70%+ capture is needed to beat the 5.28 default with margin. Best-in-class blue hydrogen plants (95% capture) deliver ~1.5 tCO2e/t — well below default.
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