3/CMP.1, Annex, paragraphs 40(a) and (f) provide that written approval from each Party involved is required for validation. However, at EB 18, paragraph 57, the Executive Board clarified that a project activity can take place without an Annex I Party being involved at the time of registration.
EB 16, Annex 6, paragraph 1 sets out the contents of the letter of approval.
EB 17, Annex 4 clarifies that letters of approval must be unconditional.
Special cases and exceptions are set out in EB 16, Annex 6, paragraph 3.
EB 76 Annex 12 adopts the procedure for dealing with the withdrawal of letters of approval from designated national authorities.
EB 78 Annex 6 provides a template of the letter of approval required for CCS project activities.