CO2 emission factors for fossil fuels Germany is obligated to report its national emissions of greenhouse gases annually to the European Union and the United Nations. Over 80 % of the greenhouse gas emissions reported by Germany occur via combustion of fossil fuels. The great majority of the emissions consist of carbon dioxide. To calculate carbon dioxide emissions one needs both the relevant activity data and suitable emission factors with the latter depending on the applicable fuel quality and input quantities. In light of these elements importance for emission factors the German inventory uses country specific emission factors rather than international average factors. To determine such factors one requires a detailed knowledge of the fuel compositions involved especially with regard to carbon content and net calorific values. The present publication provides an overview of the quality characteristics of the most important fuels used in Germany and of the CO2 emission factors calculated on the basis of those characteristics. Since annual greenhouse gas emissions have to be calculated back to 1990 the study also considers fuels that are no longer used today. To that end archival data are used. Gaps in the data are closed with the help of methods for recalculation back through the base year.