Non-CO2 greenhouse gas emissions from boilers and industrial processes: Evaluation and update of emission factors for the Finnish national greenhouse gas inventory

Finland is obligated to report anthropogenic greenhouse gas emissions annually to the UNFCCC. Inventories of greenhouse gas emissions and methodologies used have to be well based and documented. The aim of this report is to give input to Finnish greenhouse gas inventory of energy (stationary combustion) and industrial sectors. The emission factors for the industrial processes used in the inventory are based both on plant-specific factors and the IPCC default values. The currently used emission factors for the non-CO2 greenhouse gases from combustion are mainly based on studies done at the beginning of 1990's, even though small modifications to the emission calculation model have been done afterwards. Since 1990, significant changes have occurred in plant design and maintenance, operating conditions and composition of fuels. In addition, knowledge of emission generating processes has increased world-wide. In this study, the non-CO2 emission factors (mainly CH4 and N2O, and at a lesser extent, CO and NMVOC) for combustion and industrial processes used in the Finnish greenhouse gas inventory are evaluated based on domestic and international literature, available measurement data and expert interviews. Results of this study revealed many potential areas for improvements in the inventory. Consequently, recommendations to update the CH4 and N2O emission factors from boilers and industrial processes are given including guidance on the level of the calculations. The time dependency and uncertainties of the emission factors are also considered. In addition, effect of load and fuel mixes on emissions is examined. Areas for further research are also indicated.