Compliance · GHG Protocol · 5 min read
GHG Scope 3.
Supplier energy, audit-grade.
Scope 3 emissions inherit your suppliers' data quality. Today, the best you get is a PDF. Tomorrow, you get a signed certificate your supplier cannot retract and your auditor can verify offline.
The Scope 3 problem in one sentence
You are accountable for emissions you did not cause, generated by counterparties who have no incentive to give you good data, measured in units (kWh, MJ, tCO₂e) they may not even own — and you have to defend the resulting number to a regulator who can challenge each step.
What today's supply-chain data looks like
- Email + spreadsheet. Sometimes a portal. Numbers arrive late, in different formats, with different definitions of the same field.
- No primary evidence. The supplier rarely shares the meter reading; usually a derived monthly aggregate.
- No timestamp guarantee. The same supplier can adjust historical numbers between filings.
- No portability. If you switch ESG software, the evidence chain breaks.
What Serial Alice changes
Suppliers issue signed energy certificates from their own infrastructure. The certificates contain:
Signed energy readingHardware-measured kWh, signed at capture by the supplier
Per-product attributionEnergy per unit, per shift, per production line — not annualised averages
Public timestampAnchored on Polygon mainnet, dated by the chain not the supplier
Portable bundleOne JSON file, verifiable in any tool, forever
Independent issuer keySupplier's signing key, not Serial Alice's — verification holds even if Serial Alice disappears
Counterparty verifiesYou re-derive your own Scope 3 number from the supplier's primary evidence
See a supplier certificate
Verify a real production-line energy attestation end-to-end.
Verify a certificate →
How this lands inside the GHG Protocol
Scope 3 Category 1 (Purchased goods and services) and Category 11 (Use of sold products) are the two largest typical sources for any hardware-using business. Both are dominated by supplier data quality. The GHG Protocol's "hierarchy of data quality" ranks supplier-specific primary data with documented methodology at the top.
Cryptographic attestation is the practical implementation of "supplier- specific primary data with documented methodology". The methodology is in the signed canonical payload. The primary data is in the signed energy_wh field. The documentation is the bundle.
CBAM — the same primitive, different regulator
The EU Carbon Border Adjustment Mechanism asks importers to declare the embedded carbon of imported goods. Importers are now liable for numbers their non-EU suppliers produce. Same evidence problem, same solution: signed certificates from the supplier, verifiable by the importer, defensible at customs.