VCS quality assurance principles ensure all VCUs represent GHG emission reductions or removals that are real, measurable, additional, permanent, independently verified, conservatively estimated, uniquely numbered, and transparently listed. To that end, all VCS projects and VCUs are:


Projects must exceed the likeliest “business-as-usual” scenario and demonstrate that GHG emission reductions or removals would not occur without revenue from the sale of VCUs.

Real and measurable

  • Projects must apply an approved methodology to ensure net GHG emission reductions or removals which must have already taken place, and are measurable.


Projects must use conservative assumptions, values and procedures to ensure emission reductions are not overstated.


Independently Verified

  • Projects must contract an approved validation/verification body (VVB) to confirm that the project design meets VCS criteria and that all GHG emission reductions or removals are quantified according to VCS requirements.

Uniquely numbered and transparently listed

  • Projects must register with the Verra Registry operator to ensure each VCU is assigned a unique serial number and listed on the Verra Registry.