Serial Number Guide

All Carbon Reduction Tons (CRTs) created within the Reserve are assigned a unique serial number to
eliminate double counting of CRTs as well as provide a pedigree for each CRT created. The unique serial
numbers associated with the CRTs persists as the CRTs are transferred between account holders and

CRTs are issued to projects in “batches,” with each batch representing a quantity of CRTs awarded to a
single project for a specific reporting period. The format of the Reserve serial numbers encodes project
and registry information into the serial number. The table below identifies the serial number format that
will be used by the Reserve.

Identifier Description Range of Values
Originating Registry Alphanumeric used to identify the registry originally issuing project credits. If transfer agreements between additional registries are created in the future, they would use other codes. CAR = Climate Action Reserve
Unit type Identifier of the type of offset credit issued 1 = Climate Reserve Tonne (CRT)
ROC = Registry Offset Credit
Project Country Two-letter ISO country codes US = United States
MX = Mexico
Project ID Number assigned by the Reserve to identify the project; unique to the originating registry
Project Type Number identifying the project category 1 = Forest Conservation-Based Management
2 = Forest Conservation
3 = Reforestation
4 = Landfill Gas Capture/Combustion
5 = Livestock Gas Capture/Combustion
6 = Improved Forest Management
7 = Avoided Conversion
22 = Urban Forestry – Municipality
23 = Urban Forestry – Educational Campus
24 = Urban Forestry – Utility
27 = Organic Waste Digestion
28 = Coal Mine Methane – VAM
29 = Coal Mine Methane – Drainage
30 = Nitric Acid N2O- Secondary Catalyst
31 = Nitric Acid N2O- Tertiary Catalyst
32 = Ozone Depleting Substances – U.S
33 = Ozone Depleting Substances – Article 5 Imports
34 = Rice Cultivation
36 = Nitrogen Management
102 = Reforestation – ARB Compliance
105 = Livestock – ARB Compliance
122 = Municipality – ARB Compliance
123 = Educational Campus – ARB Compliance
124 = Utility – ARB Compliance
125 = Improved Forest Management – ARB Compliance
126 = Avoided Conversion – ARB Compliance
132 = Ozone Depleting Substances – U.S. – ARB Compliance
Project Developer ID Number assigned by the Reserve for the project developer; unique to the originating registry
Project State Abbreviation Two-letter state abbreviation
Vintage Year the emission reduction/removal occurred Format = YYYY
Batch Number Number assigned to each batch of offsets created; unique to the originating reserve 1 – 99,999
Unit Serial Block Start Numbers assigned by the Reserve 1 – 999,999,999
Unit Serial Block End Numbers assigned by the Reserve 1 – 999,999,999

Example: This serial number identifies a batch of 29250 CRTs issued by the Reserve to developer #120
for project #293 for reductions in 2006.

CAR-1-US-120-1-293-CA-2006-102-1 to 29251

Look up serial numbers here.