Proposal of a modelling framework for prospective hybrid life cycle assessment and application to a novel biorefinery system

Life cycle assessment (LCA) represents the most established and well-developed tool for measuring environmental sustainability of products, relying on an internationally standardised methodology for the quantification of product’s impacts through all phases of its life cycle. However, despite the standardisation has contributed to its broad acceptance and use, several limitations have been pointed out over the past years and LCA is still undergoing an intense research effort. The general objective of this research is to develop an advanced LCA framework to be used as a supporting tool for decision-making. The case study for the application of the proposed framework is the novel biorefinery system currently investigated in European H2020 project To-Syn-Fuel. The ambition of this project is the demonstration of the integrated approach which combines Thermo-Catalytic Reforming (TCR) technology, a thermochemical process of biomass conversion, to Pressure Swing Adsorption (PSA) and Hydro-deoxygenation (HDO). The integrated TCR-PSA-HDO process is expected to enable the production of a fully equivalent gasoline and diesel substitute and green hydrogen for use in transport, using sewage sludge as feedstock. The goal of the present environmental assessment is to measure the environmental consequences of the decision to implement the TCR-PSA-HDO technology in Europe (compared with business as usual), according to the targets for future market deployment envisaged by the To-Syn-Fuel project. The proposed framework combines the use of process-based data, input-output data and dynamic scenarios, which can be included in one single tool to go beyond the modelling limitations and simplified assumptions of a conventional LCA. Practically, a dynamic hybrid input-output table is built, reflecting the gradual implementation of the technology over time and the evolution of future energy scenarios. This work demonstrates the importance of measuring environmental sustainability not as intrinsic property of products, but as a feature strictly dependent on the context and its dynamics.