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Validation and Verification

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

Verification is a risk-based process carried out in conformance with ISO 14064-3:2006 and ISO 14065:2007. 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 14065:2007.

Verification bodies for California compliance projects must be accredited by the California Air Resources Board (ARB). All VVBs for voluntary market projects must be approved by ACR through the process below, and either be ANSI-accredited in the applicable sectoral scope, or be Designated Operational Entities approved under the Clean Development Mechanism or Accredited Independent Entities approved under Joint Implementation.

Information Requirements

For voluntary carbon market projects and California Early Action projects, ACR requires that all ACR Approved VVBs execute an Attestation of Validation/Verification Body, which defines the VVB role and responsibilities and ensures technical capabilities and no conflicts of interest. ACR Approved VVBs must also execute a Project-Specific Conflict of Interest Form for each project validated and/or verified.

Validation and Verification activities must address all requirements listed in the American Carbon Registry Standards and follow ACR Validation and Verification Guidelines. 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 already completed all other required steps, ACR will register the project; post the GHG Project Plan, verification statement, and other documentation to the ACR website; and issue serialized ERTs to the Project Proponent’s account.

Validation and Verification Interval

ACR requires verification at specified intervals in order to issue new ERTs. Validation of the GHG Project Plan is required once per crediting period. 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 at the Proponent’s request, more or less frequently. 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.

No less than once every five years, Proponents must submit a verification statement based on a full verification including a field visit to the project site. Further qualifications are detailed in the American Carbon Registry Standard v2.1 and relevant sector standards.

ACR Approved Validation and Verification Bodies (VVBs)

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

ACR Approved MethodologyRequired Corresponding ANSI Scope Accreditation
Conversion of High-Bleed Pneumatic Controllers in Oil and Natural Gas SystemsSector 2: GHG emission reductions from industrial processes (non-combustion, chemical reaction, fugitive, and other)
Improved Forest Management (IFM) – All Methodologies

Sector 3: Land Use, Land Use Change and Forestry

Afforestation and Reforestation (A/R) of Degraded Lands - All methodologies

Sector 3: Land Use, Land Use Change and Forestry

Emissions Reductions through Changes in Fertilizer Management

Sector 3: Land Use, Land Use Change and Forestry

Reduced Emissions from Deforestation and Degradation (REDD) – All Methodologies

Sector 3: Land Use, Land Use Change and Forestry

Livestock Waste Management

Sector 5: Livestock

Landfill Methane

Sector 6: Waste handling and disposal

Becoming an ACR Approved Verification Body

Entities seeking to become an ACR Approved Validation and Verification Body can apply by sending a completed verifier application form, including all required attachments 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
ACR Verifier Application
Attn: Pia Mayer
2121 Crystal Dr., Suite 500
Arlington VA 22202

Please direct any questions to