Well-to-Gate Greenhouse Gas Emissions of Petrochemical Products across the Supply Chain and Sources of Variability in China

The carbon-intensive petrochemical sector plays a critical role in numerous industrial supply chains. However, existing databases lack comprehensive carbon footprint profiles for petroleum products, hindering reliable assessments of greenhouse gas (GHG) emissions associated with derived chemicals and various downstream products. This study developed a quantification method that converts the material flows of oil refineries into input-output coefficient matrices using actual plant data, which further refined process-specific GHG emission estimates and identified key sources of variability across the full spectrum of petroleum products. The results show that inconsistent allocation methods lead to 40%-80% of the variation in emission estimates, while data uncertainty has a moderate influence. Configuration heterogeneity also affects GHG assessments by altering the process mix and upstream processes─specifically, a lower proportion of straight-run oil and deeper processing of heavier fractions result in higher emissions. Additionally, the aggregation of oil-based intermediates as chemical feedstocks introduces an uncertainty range of -19% to +44% in assessing the GHG emissions of major chemicals. This underscores the importance of comprehensive GHG emission profiles and variability analysis of petroleum products in advancing reliable emission assessments and decarbonization strategies for the petrochemical industry.