Using a combination of metamodels, ontologies, green performance indicators and metrics, we apply a novel approach in Semantic Business Process Benchmarking to the area of Green Business Process Management (Green BPM). Up to now, process benchmarking has mainly been a manual process; the approach described and empirically evaluated in this paper partially automates the time-consuming and costly process analyses while introducing more flexibility regarding varying terminology, level of abstraction and modeling notation. Also, overviews of literature relevant to the field of Green Semantic BPM and commonly applied metrics in a Green BPM context are given.