​
Introduction

This page defines concepts found in the Isometric Registry, and used in the Registry API. For a broader understanding of the requirements and processes governing the Isometric Registry, please refer to the Isometric Standard.

​
Key Concepts

​
Buyer

An entity (usually a corporation, but can also be an individual or a government entity) that purchases CDR, often with the purpose of retiring CDR credits to make a carbon neutral or net-negative claim.

​
Beneficiary

The organization benefiting from the Removal claim afforded by a Credit. This may be the current holder of the Credit at the time of Retirement, or an organization specified by the Credit account holder during the Retirement procedure.

​
Supplier

An entity that removes carbon dioxide from the atmosphere so that it can be stored durably and sells this service to buyers.

​
Project

An activity or process or group of activities or processes that alter the condition of a Baseline and leads to Removals.

​
Credit

A publicly visible uniquely identifiable Credit Certificate Issued by a Registry that gives the owner of the Credit the right to account for one net metric tonne of Verified CO₂e Removal. In the case of this Standard, the net tonne of CO₂e Removal comes from a Project Validated against a Certified Protocol.

​
Credit Batches

A ‘Credit Batch’ is a grouping of 1 or more credit units, where each credit unit represents 1kg of CO₂e removed.

When credits are initially Issued, they will be batched together with status ACTIVE. When subsequent transactions are made using these credits, including deliveries, retirements and transfers, a batch might be split to make this possible.

All credits in batch will always have the same initial Supplier, Project and Issuance.

​
Credit Batch Splitting

If the quantity of credits in a transaction request (delivery, transfer or retirement) does not match the full size of the submitted credit batches, the batches submitted will be split in order to transact the exact credit amount requested.

When a credit batch is split, its status will be updated to SPLIT and it can no longer be interacted with.

Two child batches representing the two halves of the split are created with an ACTIVE status. The child batches will have a parent_id set pointing at the originally split batch. From the parent split batch, you can find its two children via the left_child_id and right_child_id fields.

​
Buffer Pool

A pool of credits that are held in Supplier specific accounts and will be cancelled in the case of a reversal.

​
Issuance

Credits are issued to the Credit Account of a Project Proponent with whom Isometric has a Validated Protocol after an Order for Verification and Credit Issuance services from a Buyer and once a Verified Removal has taken place.

​
Delivery

The outcome of a supplier apportioning removals into orders to fulfill their buyers’ purchases. A removal can only be delivered after it has been verified.

​
Retirement

The mechanism by which a Credit’s ownership state is finalized. This ensures that once the net tonne of CO₂e represented by the retired Credit is used towards an accounting activity, it can never be used again by the owner, the Beneficiary of the retirement, or any other actor. A credit batch will have status RETIRED once it has been retired.

​
Order

A set number of tonnes that a buyer purchases from a supplier in a given contract.