What is registration?
Registration is defined in 3/CMP.1, Annex, paragraph 36:
Registration is the formal acceptance by the Executive Board of a validated project as a CDM project activity. Registration is the prerequisite for the verification, certification and issuance of CERs relating to that project activity (3/CMP.1, Annex, paragraph 36).
Therefore, registration is a key stage in the CDM project cycle, representing the point where a project activity is accepted as a CDM project, making it eligible to generate certified emission reductions (CERs).
This decision for large-scale projects applies equally to small-scale projects:
The CDM modalities and procedures shall apply to small-scale CDM project activities except for its paragraphs 37 to 60 (4/CMP.1, Annex II, paragraph 11).