Standard · Verified Unit
The verified unit
A carbon claim is only as good as the smallest thing anyone can check. This page defines
that thing: the verified unit — one batch, one boundary, one ledger entry, one recomputable hash.
What a unit is for. It is the unit our evidence layer sells. A buyer who needs primary
scope-3 data pays per unit; the grower pays nothing. It is not a credit, not an offset, and not a certificate.
What makes a unit verifiable
| Property | What it means in practice | Fails when |
|---|
| Metered | The number comes from a meter, not from a spend-based estimate | Only invoices exist for the energy |
| Bounded | Boundary and functional unit are fixed before the data arrives | The boundary is chosen after seeing the result |
| Attributed | One owner, one location, one batch id — no allocation by proportion | A batch is split across sites without a rule |
| Committed | The record is hashed into the chain at issuance and cannot be edited afterwards | The number is revised silently |
| Recomputable | A third party reproduces the hash from published fields, without our server | Verification requires asking us |
A unit that fails any one of these is not a weaker unit. It is not a unit.
What a unit carries
| Field | Meaning |
|---|
| unit_id | Batch identifier, immutable once issued |
| boundary | Cradle-to-gate or whichever boundary the method fixes |
| functional_unit | kgCO₂e per plantlet, per kg, per unit of output |
| metered_share | Share of the footprint from primary data; decides the grade |
| grade | A / B / C, set by the metered share, not by the customer |
| hash, prev_hash | FNV-1a over canonical fields plus the previous record |
| method | Method id and version the number was produced under |
Grades
| Grade | Metered share | What it buys |
|---|
| A | ≥ 70% | Primary scope-3 line item, admissible in most supplier programmes |
| B | ≥ 45% | Usable with a stated share of secondary factors |
| C | < 45% | Directional; discloses how much is estimated |
The grade is a statement about data, not about the organisation. A C-grade unit from a well-run site is
still a C; an A-grade unit from a site we have never met requires the metering to prove itself first.
Who pays
| Party | Pays | Why |
|---|
| The buyer | ¥40–80 per batch (A ¥80 / B ¥60 / C ¥40) | It needs primary scope-3 data, and its own reporting obligation creates the demand |
| The grower | Nothing for the unit | The measurement is a by-product of running the site; charging the supplier builds the wrong incentive |
This is the fee schedule, published rather than negotiated. See the
fee schedule for the buyer-side table and what the signature share is.
What a unit is not
| Not | Why it matters |
|---|
| A carbon credit or offset | Nothing is traded, retired or claimed against another party's emissions |
| A certification | No accreditation body has certified this body; conclusions are countersigned by a partner |
| Comparable across methods | A unit is comparable only inside the method version that produced it |