Applying bottom-up analysis to identify the system boundaries of non-energy use data in international energy statistics

Data on the non-energy use of fossil fuels in energy statistics are subject to major uncertainties. We apply a simple bottom-up methodology to recalculate non-energy use for the entire world and for the 50 countries with the highest consumption of fossil fuels for non-energy purposes. We quantify worldwide non-energy use in the year 2000 to be 24±2 exajoules (EJ), thereby accounting for 6% of the global total primary energy supply (TPES). Our bottom-up estimates are in line with data from international energy statistics for the entire world and for 14 individual countries. Our estimates exceed official non-energy use data for 22 countries, whereas they are lower than official data in the case of 14 countries. Inconsistent system boundaries of non-energy use data in international energy statistics can explain parts of the observed deviations. We regard our bottom-up methodology as reliable albeit being attached with uncertainties. We recommend its use for energy statisticians and greenhouse gas (GHG) inventory makers to generate a shortlist of countries, for which efforts should be made to clarify and improve the quality of non-energy use data in national and international energy statistics.