Certified emission reductions obtained during the period from the year 2000 up to the beginning of the first commitment period can be used to assist in achieving compliance in the first commitment period.
The crediting period is the duration of time selected by the project participants during which the CDM project activity will be implemented and greenhouse gas emission reductions (and consequently CERs) will be generated.
An exception was made to this general rule to allow for the 'prompt start' of the CDM. Project activities that commenced before the first registration of a CDM project (which occurred on 18 November 2004) and were submitted for registration before 31 December 2005 (or in certain circumstances, were not submitted for registration by this date but were registered by the Executive Board by 31 March 2007) were permitted to use a crediting period starting prior to the date of registration, but not earlier than 1 January 2000.
As this exception has now expired, the general rule is that the crediting period can only commence, and CERs can only be issued, after the date of registration. The starting date and length of the first crediting period must be determined before registration, and this information must be included in the request for registration.
However, decision -/CMP.6 requested the EB to revise the procedures for registration to allow the effective date of registration and the possible start date of the crediting period to be the date on which a complete request for registration is submitted by the DOE where the project is registered automatically (-/CMP.6, paragraph 56).