PCS POL 001 Serial Numbering Policy_v1.0

Document Control

• Owner: PCS Registry / PCS Secretariat

• Approver: PCS Governance (as applicable)

Table VC-1. Revision history

Version	Date	Status	Summary of changes	Prepared by	Approved by
1.0	TBD	Draft	Release for public consultation	PCS	TBD

Superseded versions

None (initial release).

Governance note on versioning and archiving

Only the latest approved version of this Policy shall be used. Superseded versions shall be archived and retained for traceability and audit purposes. This Policy’s serial numbering schema shall not be changed retroactively; any updates require formal versioning and public disclosure.

Chapter 1 - Purpose

This policy defines how carbon credit serial numbers are issued, structured, managed, and referenced within the Planetary Carbon Standard (PCS) Registry. The objective is to ensure uniqueness, traceability, permanence, and auditability of all carbon credits across their full lifecycle.

Chapter 2 - Scope

This policy applies to:

• All PCS-issued carbon credits

• All credit statuses: issued, held, transferred, and retired

• All registry records, certificates, dashboards, APIs, and public disclosures

• All integrations with blockchain or other digital infrastructure

Chapter 3 - Principle of Credit Identity

1. Every carbon credit issued under PCS must have a unique serial number or serial number range.

2. The serial number (or range) constitutes the legal and technical identity of the carbon credit.

3. Serial numbers are:

   • Unique

   • Immutable

   • Never reused

   • Never reassigned

4. Serial numbers identify individual tonnes (or batch ranges of tonnes) of CO₂e, not transactions, wallets, or certificates.

Chapter 4 - Serial Number Structure

PCS serial numbers follow a structured, machine-readable format encoding key credit attributes.

Canonical format:

PCS-[Vintage]-[ProjectID]-[ProjectCode]-[IssuanceBatch]-[UnitRange]

Example:

PCS-2023-0001-SANZ-0001-00001–00005

Component definitions:

• PCS Registry identifier (Planetary Carbon Standard)

• Vintage Credit vintage year (or vintage start year where applicable)

• ProjectID Unique PCS-issued project identifier

• ProjectCode Fixed project or developer code (optional but immutable once assigned)

• IssuanceBatch Sequential issuance batch number for the project

• UnitRange Continuous numeric range representing individual carbon credits (each number = one tonne CO₂e)

Chapter 5 - Serial Numbers by Credit Status

5.1 Issued and Held Credits

• Serial numbers (or ranges) represent the credit identity

• Credits may be held in registry accounts or digital wallets

• No blockchain transaction hash is required or relevant for identity

• Inventory accounting is based on serial ranges

5.2 Transferred Credits

• Serial numbers remain unchanged during transfers

• Transfers may optionally be recorded on-chain

• Any transaction hash is treated as transfer evidence only

• Serial numbers remain the authoritative identifier

5.3 Retired Credits

• Retirement is a permanent, irreversible status change

• Retired credits retain their original serial numbers

• Retirement records must include:

  • Serial number or serial range

  • Quantity

  • Beneficiary

  • Retirement date

• A blockchain transaction hash may be recorded as immutable proof of the retirement event

6. Use of Blockchain Transaction Hashes

1. Blockchain transaction hashes are not serial numbers.

2. Transaction hashes may be used only as:

   • “Blockchain retirement reference”

   • “On-chain retirement proof”

3. Transaction hashes:

   • Identify events, not credits

   • Cannot replace serial numbers

   • Cannot be used for held or inventory credits

4. PCS explicitly prohibits labelling a transaction hash as a “credit serial number” in any context.

7. Certificates and Public Disclosure

All PCS retirement certificates must include, at minimum:

1. Serial number or serial number range

2. Quantity of credits retired

3. Project ID and vintage

4. Beneficiary name

5. Retirement date

6. Blockchain transaction hash (if applicable), clearly labelled as retirement proof

Example wording:

“Carbon credits bearing serial numbers PCS-2023-0001-SANZ-0001-00001–00005 have been permanently retired on [date] for the benefit of [beneficiary]. The retirement event has been immutably recorded on-chain under transaction hash [hash].”

8. Governance and Controls

• Serial number issuance is controlled exclusively by PCS Registry governance

• Serial schemas may not be altered retroactively

• Any changes to this policy require formal versioning and public disclosure

• Misrepresentation of transaction hashes as serial numbers constitutes a breach of PCS registry rules

9. Alignment Statement

This policy is designed to align conceptually with best practices used by leading carbon standards (e.g. Verra, Gold Standard, ART) while enabling additional transparency through blockchain-based audit trails without compromising credit integrity.

10. Effective Status

This policy is effective as of the date stated above and applies to all PCS credits issued thereafter.