Sustainability Risk Screening: the Definition and Undertaking of a Counterfactual Sustainability Screening Assessment of Defossilised Olefin Supply Chains

With the increase in societal, economic and political pressures towards a more sustainable future, the understanding of prospective supply chain viability has never been more pertinent within the chemical industry than it is today. In response to these pressures, household name Unilever’s Home Care division has set ambitious targets for the future with their ‘Clean Future’ initiative, with a pledge to defossilise all their carbon feedstocks by 2030 and operate at net zero carbon emissions by 2039. In view of these targets, this thesis outlines the requirement, development and validation of a sustainability viability screening assessment, with the aim of improving the early understanding of prospective, defossilised supply chains. Following two literature reviews into defossilised supply chain technologies and sustainability decision-making methods, a sustainability viability screening assessment was developed. In addressing drawbacks of existing methods concerning impact magnitude prediction, uncertainty and operator bias, a novel basis of assessment is proposed, utilising probability prediction of indicator performance against a defined baseline. The methodology used eleven weighted indicators and provided a performance summary of eighteen different defossilised supply chains for Linear Alkylbenzene Sulfonate (LAS) olefins, for the application of sustainable surfactants within Home Care cleaning products. Key insights from the assessment included the importance of feedstock renewability, energy demand and economic performance, with feedstocks utilising end-of-life biomasses and plastics favouring those driven by carbon capture. The methodology was also programmed into a functional tool, providing an intuitive userinterface for operators to report and track the performance of prospective technologies as they are developed or introduced to market. Efforts to validate these conclusions are then presented, through the undertaking of industrially standardised or recognised life cycle and techno-economic assessments for four supply chains. The conclusions from these assessments confirmed many of the red and green flags of the screening assessment, highlighting the potential for decision-informing evidence derivation from semi-quantitative means.