Abstract: Accurate quantification of greenhouse gas (GHG) emissions is fundamental to achieving greenhouse gas reduction targets. The combustion of fossil fuels, including coal, fuel oil, and natural gas, is a predominant source of GHG emissions. This study focuses on the determination of carbon dioxide (CO₂) emissions from stationary combustion sources using fuel analysis methods. Two distinct methods are presented: Method 1 utilizes the fuel’s calorific value and emission factor to ascertain the CO₂ emissions, while Method 2 employs the fuel’s carbon content and oxidation rate for this determination. This paper elaborates on the procedural steps, analytical methodologies, instrumentation, calibration techniques, and uncertainty assessments applied in both methods. Comprehensive metrological techniques encompassing primary calorimeters, certified reference materials for calorific values, elemental contents, and natural gas components, as well as verification regulations and calibration protocols, are employed to ensure the accuracy, reliability, and consistency of the CO₂ emission determinations.