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Validation and Verification

The American Carbon Registry (ACR) requires independent third-party validation and verification of all voluntary carbon offset projects following the ACR Validation and Verification Standard.

Validation and verification are risk-based processes carried out in conformance with ISO 14064-3:2006 and ISO 14065:2013. ACR validation and verification bodies (VVBs) shall be accredited for project validation and verification and the scope of the applicable methodology, and VVB teams shall meet the competence requirements as set out in ISO 14065:2013 and ISO 14066:2011.

All VVBs for voluntary market projects must be approved by ACR through the process below, and be IAF member- accredited in the applicable sectoral scope. VBs for California compliance projects must be accredited by the California Air Resources Board (ARB).

Information Requirements

ACR requires that all ACR-approved VVBs execute an Attestation of Validation/Verification Body, which defines the VVB role and responsibilities and confirms technical capabilities and no conflicts of interest with ACR. ACR-approved VVBs must also execute a Project-Specific Conflict of Interest Form for each project validated and/or reporting period verified.

Validation and verification activities must address all program requirements listed in the American Carbon Registry Standard and follow the requirements of the ACR Validation and Verification Standard. Projects must be verified without reservation, with project proponents having addressed all clarifications and corrections required by the VVB.

Once ACR reviews and accepts a verification statement, and the project proponent has completed all other required steps, ACR will post the verification report, verification statement, and other documentation to the public ACR website, and issue serialized ERTs to the project proponent’s account.

Validation and Verification Interval

Validation of the GHG Project Plan is required once per crediting period. ACR requires verification at specified intervals in order to issue new ERTs. Validation and the first verification may be conducted simultaneously, and may be conducted by the same approved validation and verification body (VVB).

ERTs may be created and issued annually, or more or less frequently at the Proponent’s request. At each request for issuance of new ERTs, the Project Proponent must submit a verification statement from an approved VVB based on a desk audit. Projects must also undergo a full site visit verification at an interval no longer than 5 years. Further details are specified in Chapter 9 of the American Carbon Registry Standard, and Chapter 10 of the ACR Validation and Verification Standard.

ACR-Approved Validation and Verification Bodies (VVBs)

A list of validation / verification bodies that have been approved by ACR can be accessed here.

Becoming an ACR-Approved Validation/Verification Body

Entities seeking to become an ACR-approved Validation and Verification Body can apply by sending a completed Application for Validation/Verification Body Approval, including all required attachments, and an Attestation of Validation/Verification Body to A copy of the application form (no attachments) and a check for the $2000 application fee or $500 scope expansion fee should be mailed to:

Winrock International
American Carbon Registry VVB Application
2451 Crystal Drive, Suite 700  
Arlington, VA 22202 USA

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