In this study we were able to identify uncertainties in the mapping between GHG protocols as well as in the aggregation process from ALKIS classes to GHG protocols using bottom-up data.
In terms of data aggregation to GHG reporting classes we were able to identify a strong heterogeneity in the building stock using the heating cadaster data mapped on the CityGML model.
This concept was supported by the skewness GHG emissions from buildings within a reporting class, indicating that mean values are not necessarily the most common emission values
in a particular class.
Also the different class resolution in the GHG reporting protocols influence the reported
sectorial values due to the smoothing effect of higher building numbers in particular large classes.
Finally the linkage between the CityGML 3D city model building information with ALKIS energy and GHG data seems to be a suitable approach to develop MRV tools for cities which are able to report under different protocols