Upscaling in ex-ante sustainability assessments of emerging chemical technologies: a scoping review

The chemical industry is transitioning towards sustainability. Early-stage emerging technologies (technology readiness levels 1–4) play a critical role in enabling this transition. These technologies can either resemble mature unit-operation-based incumbents (traditional designs) or adopt innovative multi-functional (non-traditional) designs. While promising, their immature nature entails high investment risks. Ex-ante sustainability assessments (ex-ante SAs) help mitigate these risks by evaluating how early design decisions influence industrial-scale sustainability impacts. A crucial challenge in ex-ante SA is upscaling, the process of modelling an industrial-scale version of an emerging technology based on lab-scale insights. Despite its importance, existing literature lacks a systematic classification of methodological approaches for upscaling, making it difficult to select appropriate approaches based on a technology's design features. We address this gap by conducting a scoping literature review on emerging bio-based, electrochemical, and chemical CO2 management process technologies. Based on our findings, we propose a classification scheme that categorizes upscaling methodologies according to key technology features, specifically degree of intensification, extent of modularization, and design-infrastructure compatibility. These technology features are also mapped against innovative elements of the technology induced by the use of novel feedstock, or functional/auxiliary materials or equipment designs to produce (novel) end-products. This study provides practical recommendations for selecting appropriate modelling approaches for both traditional and non-traditional technology designs in ex-ante SAs. By bridging this methodological gap, our study enhances the robustness and applicability of ex-ante SA in guiding sustainable technology development.