Calculation of global carbon dioxide emissions: Review of emission factorsand a new approach taking fuel quality into consideration

Anthropogenic carbon dioxide emissions resulting from fossil fuel consumpti on play a major role in the current debate on climate change. Carbon dioxid e emissions are calculated on the basis of a carbon dioxide emission factor (CEF) for each type of fuel. Published CEFs are reviewed in this paper. It was found that for nearly all CEFs, fuel quality is not adequately taken i nto account. This is especially true in the case of the CEFs for coal. Publ ished CEFs are often based on generalized assumptions and inexact conversio ns. In particular, conversions from gross calorific value to net calorific value were examined. A new method for determining CEFs as a function of cal orific value (for coal, peat, and natural gas) and specific gravity (for cr ude oil) is presented that permits CEFs to be calculated for specific fuel qualities. A review of proportions of fossil fuels that remain unoxidized o wing to incomplete combustion or inclusion in petrochemical products, etc., (stored carbon) shows that these figures need to be updated and checked fo r their applicability on a global scale, since they are mostly based on U.S . data.