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Registry Functions

Registries record the holdings of Kyoto units, and any transactions involving them, through a structure of accounts.  This is similar to the way that banks record balances and movements in money using accounts allocated to individuals or other entities.  

pdf-icon Data Exchange Standards (4322 kB) have been developed to coordinate the electronic messaging that occurs between registry systems when processing transactions.  The types of Kyoto units and transactions enabled by these standards are summarized in the tables below.  The ITL, CITL and registries also process unit types and transactions defined under other emissions trading schemes, such as EU allowances for the first phase of the EU trading scheme and other transaction sub-types defined under this scheme. 

The data held by registries is reconciled on a daily basis with data in the ITL and CITL. Procedures are in place for identifying and resolving any inconsistencies discovered.

 Kyoto units

 Unit name

 Issuer  Description

 Kyoto Protocol


Amount Units

 National registry

 Units representing the initial assigned amount of each Annex B Party

 Article 3.7



 National registry

Units given for net removals from land use, land-use change and forestry activities

 Article 3.3, 3.4



 National registry

Units converted from AAUs or RMUs on the basis of JI projects  Article 6



Credits given for emission reductions certified for a CDM project  Article 12



Credits given for emission removals certified for an afforestation or reforestation CDM project (to be replaced upon expiry at end of the second commitment period)  Article 12



Credits given for emission removals certified for an A&R CDM project
(to be replaced upon expiry at end of the project’s crediting period or
in event of storage reversal or non-submission of a certification report)
 Article 12


Kyoto transaction types
Issuance Initial creation of an AAU, RMU, CER, tCER or lCER
Conversion Transformation of an AAU or RMU into an ERU based on a JI project
External transfer External transfer of a unit from one registry to another registry
Cancellation Internal transfer of a unit to a cancellation account, in order that it may not be used for compliance with an emission target
Replacement Internal transfer of a unit to a replacement account, in order to replace tCERs or lCERs when required
Retirement Internal transfer of a unit to a retirement account, in order that it can be used by the Annex B Party for compliance with its emission target
Carry-Over Change of validity an AAU, ERU (only those converted from AAUs) or CER from one commitment period to the next
Expiry date change Change in the expiry date of a tCER or lCER 
Internal transfer between holding accounts Internal transfer of a unit between holding accounts within the same registry (the ITL does not verify such transactions but forwards them to the CITL to allow their verification under the EU  trading scheme)