Determination of country-specific greenhouse gas emission factors for South African liquid and gaseous fuels

Abstract

Higher-tier methods for greenhouse gas reporting require country-specific emission factors for a range of liquid and gaseous fuels for both stationary and mobile fuel combustion activities. Samples of selected liquid fuels used in South Africa were collected over the summer and winter seasons in the Gauteng, Mpumalanga, Free State, KwaZulu-Natal and Western Cape provinces of South Africa, primarily from large retail stations along major traffic routes (unleaded petrol – ULP93 and ULP95 – and diesel). Liquid fuels used in smaller volumes (bio-ethanol, paraffin, jet kerosene, aviation gasoline and heavy fuel oil) were also sampled at appropriate locations. Samples (343 in total) were analysed for carbon content using standard methods at an accredited commercial laboratory. Calorific values of the fuels were also determined, to allow for the calculation of methane and nitrous oxide emission factors. Results were statistically analysed to determine mean values and their uncertainties, to identify outliers, and to determine correlations between variables. Results for ULP93 and ULP95 were weighted by their respective 2021 annual average sales volumes to obtain an average value for all petrol of 2 263 g CO₂/L. Based on sales data from the years 2018–2021, summer and winter results were equally weighted to obtain annual average emission factors for ULP93 (2255 g CO₂/L), ULP95 (2 265 g CO₂/L) and diesel (2 650 g CO₂/L), reflecting a slight decrease from the values contained in the 2017 Department of Environmental Affairs Technical guidelines for monitoring, reporting and verification of greenhouse gas emissions by industry. A calculation-based liquefied petroleum gas emission factor, confirmed by analysis certificates from a number of local suppliers, was found to be 3002 g CO₂/kg.