Reducing Uncertainties in Greenhouse Gas Emissions from Chemical Production

By Dr Fanran Meng from the University of Sheffield 

Uncertainties in greenhouse gas emissions estimates for petrochemical production have lacked quantification globally, impacting emissions reporting and decarbonization policymaking. Here we analyze cradle-to-gate emissions of 81 chemicals at 37,000 facilities worldwide, assessing 6 uncertainty sources. The results estimate a 34% uncertainty in total global emissions of 1.9 ± 0.6 Gt of CO2-equivalent emissions for 2020, and 15–40% uncertainties across most petrochemicals analyzed. The largest uncertainties stem from the inability to assign specific production processes to facilities owing to data limitations.

Uncertain data on feedstock production and off-site energy generation contribute substantially, while on-site fuel combustion and chemical reactions have smaller roles. Allocation method choices for co-products are generally insignificant. Prioritizing facility-level process specification in data collection for just 20% of facilities could reduce global uncertainty by 80%. This underscores the necessity of quantifying uncertainty in petrochemical greenhouse gas emissions globally and outlines priorities for improved reporting. The dataset generated offers independent emissions factor estimates based on facility-specific information for 81 chemicals, supporting future analyses.

To frame our discussion of uncertainty, Fig. 1 shows a schematic of emissions sources in the petrochemical industry and how emissions are embodied through upstream petrochemical production to final downstream products. We follow the naming conventions for chemical classification used by the IEA and refs. 35,36.
The first part of the results section addresses the two model uncertainty sources in estimating the EF of a production facility: the practitioner’s choice of allocation method and the availability of data allowing for process specificity.

Dr Fanran Meng from the University of Sheffield states, 'Our study delves into the uncertainties surrounding GHG emissions estimates in global petrochemical production, impacting emissions reporting and policy decisions. We analysed cradle-to-gate emissions of 81 chemicals at 37,000 facilities worldwide, uncovering key sources of uncertainty. Our findings reveal a 34% uncertainty in total global emissions for 2020, emphasising the need for more accurate data collection and reporting. By prioritising facility-level process specifications, we could significantly reduce global uncertainty. Check out the full paper for insights into how we can work towards more precise emissions reporting and decarbonisation policies'.

For further information click here

To download the full report click here