Despite years of development, experience, and revision, the Clean Development Mechanism’s method for assessing additionality remains controversial and contested. For some project types, additionality is relatively certain, but for large-scale power supply projects, which are expected to generate the majority of CDM credits going forward, additionality is hard to demonstrate with high confidence.
The value and integrity of the CDM may hinge on the net emissions impact of these large-scale power supply projects. If they are truly additional and operate well beyond the credit issuance period, they can lead to a decrease in global greenhouse gas emissions. If they are mostly non-additional, as research suggests, they could increase cumulative global greenhouse gas emissions by over a gigaton of CO2e through 2020.
A transition away from such CDM projects could help address the over-supply of Certified Emission Reductions (CERs), support projects that truly depend on CERs, and improve the CDM’s overall mitigation impact. However, such a transition would need to be carefully considered, bearing in mind governance and legal aspects and the need for investor confidence.
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