Method

How every number is made

Calculation

Two production processes, exactly as Implementing Regulation (EU) 2025/2547 asks for complex goods.

1 · EAF steelmaking

carbon mass balance

+Steel scrapcarbon in× 0.04
+Pig ironcarbon in× 0.15
+Graphite electrodescarbon in× 3.00
+Charge carboncarbon in× 3.04
+Raw dolomitedecomposition× 0.477
−Crude steelcarbon out× 0.04
Verified pig iron, from the ledger× 1.91

2 · Hot rolling

combustion

gas Sm³× 9,155 kcal× 0.9 NCV× 56.1 t/TJ

plus crude steel from step 1 as the internal precursor

Demo mill

0.354

t CO2e / t coil

of which pig iron

0.201

carried from upstream

Indirect (grid) emissions are reported but not charged for iron and steel (Annex II, Reg. 2023/956).

Show the equations

EAF        AttrEm = Σ carbon in − Σ carbon out (+ carbonates)    Annex I 3.15.2.2
           EE     = AttrEm + Σ M_i × SEE_i                      verified precursors
           SEE    = EE / AL(crude steel)
Rolling    AttrEm = fuel × NCV × EF × OF                         Annex II B.3.1.1
           EE     = AttrEm + M(crude steel) × SEE(crude steel)
           SEE    = EE / AL(coil)

Factors, defaults and benchmarks

Every number the engine uses, with the act it comes from.

Factor	Value	Source
naturalGasEf	56.1 t CO2 / TJ (NCV)	Reg. 2025/2547 Annex II.G table 1 (IPCC 2006 default)
naturalGasNcvPerGcv	0.9 NCV / GCV	IPCC 2006 Guidelines, Vol. 2, ch. 1, §1.4.1.2
naturalGasOxidation	1 fraction	Reg. 2025/2547 Annex II.B.3.1.1: OF = 1 may always be used
co2PerCarbon	3.664 t CO2 / t C	Reg. 2025/2547 Annex II.B.3.1.1, eq. 9
electrodeEf	3 t CO2 / t (C 0.8188)	Reg. 2025/2547 Annex II.G table 5, EAF carbon electrodes
chargeCarbonEf	3.04 t CO2 / t (C 0.8297)	Reg. 2025/2547 Annex II.G table 5, EAF charge carbon
scrapEf	0.04 t CO2 / t (C 0.0109)	Reg. 2025/2547 Annex II.G table 5, steel / steel scrap
pigIronCarbonEf	0.15 t CO2 / t (C 0.0409)	Reg. 2025/2547 Annex II.G table 5, pig iron
steelEf	0.04 t CO2 / t (C 0.0109)	Reg. 2025/2547 Annex II.G table 5, steel
limestoneEf	0.44 t CO2 / t CaCO3	Reg. 2025/2547 Annex II.G table 3
dolomiteEf	0.477 t CO2 / t CaMg(CO3)2	Stoichiometric: 2 × 44.01 / 184.40
gridEfTurkey	0.42 t CO2e / MWh	Implementing Reg. (EU) 2025/2621, Annex II (Türkiye)
kcalToKwh	0.001163 kWh / kcal	International table calorie

🇹🇷 Türkiye default values

7201 Pig iron1.850
7208 Hot-rolled flat products2.428
7209 Cold-rolled flat products2.510
7213 Wire rod2.310
7601 Unwrought aluminium1.700

+10 % in 2026, +20 % in 2027, +30 % from 2028 · Reg. 2025/2621

Free allocation benchmarks (CN 7208)

Column A · actual data

0.044

+ precursors: crude steel 0.065, pig iron 1.089

Column B · defaults

1.37

route C (D 0.481, E 0.072)

Reg. 2025/2620; 2026 values provisional.

What the importer pays

Certificates = tonnes × (embedded emissions − free allocation adjustment), floored at zero.

Verified0.354−0.221=0.132certificates/t × €82.32 =€10.90 / t

Default2.671−1.336=1.335certificates/t × €82.32 =€109.90 / t

CBAM factor: the share of free allocation still credited

97.5%26

95%27

90%28

77.5%29

51.5%30

39%31

26.5%32

14%33

0%34

Directive 2003/87/EC Art. 10a(1a). As it falls, every tonne of CO2 counts in full.

Certificate prices 2026

2026-Q1€75.36
2026-Q2€75.28
2026-Q3€82.32

European Commission. Türkiye's ETS pilot allocates for free, so no carbon price paid at origin is deducted.

What the contract guarantees

Each rule is a custom error, covered by tests and reachable from the demo.

Accredited signatures

Any field changed after signing breaks the EIP-712 signature.

NotAccreditedVerifier

Verified once

No overlapping periods per installation and product.

PeriodOverlaps

Sold once

Allocations never pass the verified tonnes; one per customs reference.

ExceedsVerifiedQuantity

Ends once

Declared or consumed downstream, never both, never twice.

AllocationNotOpen

No laundering

Precursor carbon recomputed on chain; the product cannot carry less.

BelowPrecursorEmissions

Private by default

Only a salted Merkle root on chain; fields proven one at a time.

verifyDisclosure

Quantum-ready

Verifiers co-sign with ML-DSA-65 (FIPS 204); the key's hash is registered on chain.

pqKeyHash

Correctable

Withdrawing a statement reopens its period, precursors and customs references.

Reopened

No self-attestation

A verifier cannot sign for an installation it operates.

SelfAttestation

30 contract tests28 unit tests60-step randomised allocation testindependent review, findings fixedbrowser walkthrough

AI and security

The model only reads

· Google Gemini (gemini-3.8-flash), schema-checked output
· Every number with its verbatim source text
· 29 of 29 sample lines read exactly in our evaluation
· No arithmetic, no judgement, files not stored
· Outliers flagged against cited EU BAT ranges

Plausibility ranges

electricity: 320–890 kWh / t crude steel (whole site) · EU BREF Iron & Steel 2013, tables 8.1 and 8.15; FMP BREF 2001, table A.3-4
electrodes: 0.8–6 kg / t crude steel · EU BREF Iron & Steel 2013, tables 8.1 and 8.15
chargeCarbon: 3–28 kg / t crude steel · EU BREF Iron & Steel 2013, table 8.1 (coal)
metallic: 1.039–1.232 t metallic charge / t crude steel · EU BREF Iron & Steel 2013, table 8.1
stack: 72–180 kg CO2 / t crude steel · EU BREF Iron & Steel 2013, table 8.1 (direct stack CO2)
gas: 1–2.2 GJ (NCV) / t hot-rolled · BAT conclusions 2022/2110 table 1.1 (1.2–1.5 GJ/t); FMP BREF table A.3-2 (1.1–2.2)
yield: 0.85–0.99 t hot-rolled / t crude steel · FMP BREF 2001, table A.3-4 (70–150 kg/t metallic by-products); upper bound assumed

Threat model

· 19 threats mapped to a control and a test
· A bribed verifier still cannot launder precursor carbon or reuse tonnes
· Verifiers are time-limited and suspendable; statements can be withdrawn

Read docs/security.md

Try the flow Source code