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
retired.
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 offsets. If transfer agreements between additional registries are created in the future, they would use other codes. | CAR = Climate Action Reserve |
| Unit type | Number that identifies the type of credit issued | 1 = Carbon Reduction Tons (CRTs) |
| Project Country | Two-letter ISO country codes | |
| 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 22 = Urban Forestry – Municipality 23 = Urban Forestry – Educational Campus 24 = Urban Forestry – Utility 6 = Improved Forest Management 7 = Avoided Conversion 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 |
| Project Developer ID | Number assigned by the Reserve for the project; unique to the originating registry | |
| Project State Abbreviation | Two-letter state abbreviation | |
| Vintage | Year the CRTs were awarded (vintage) with format YYYY | |
| Batch Number | Number assigned to the each batch of CRTs 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