This Recommendation aims to establish a methodological framework for assessing the contribution of VPP to mitigating climate change. As the global net-zero process accelerates, VPPs, as a key means of integrating distributed energy resources and enhancing system flexibility and low-carbon dispatch capabilities, are increasingly valued. However, there is currently a lack of unified methodology globally to measure the GHG emission reduction effects achieved by VPPs. This Recommendation will propose unified terminology, definitions, methodologies for setting assessment boundaries, assessment model, and methodologies for identifying technological pathways, which are supporting the assessment of GHG emission reduction by enablement of different types of Virtual Power Plants operation.