Carbon fibre reinforced polymer (CFRP) composites have excellent specific properties, which allow for tailorable design options, especially where weight is a key requirement. This can result in improved product sustainability, such as reduced fuel burn. Industrial environmental impact metrics are presented as a function of weight, i.e. energy intensity (MJ/kg) and global warming potential (kg CO₂eq./kg), whereby carbon fibre (CF) does not compare favourably with steel and aluminium. Unless a holistic impact of the product lifecycle is considered, decisions based on these metrics alone can inhibit their selection during early design and product development.

Life cycle assessment (LCA) offers a comprehensive approach to communicate the environmental impact (EI) for a given system to customers, governments and wider stakeholders. However, the current state of the art for CFRP composites can be incomplete, unreliable and confusing. Complicating the issue is the increasing range of sources for fibre precursors, the diverse subsequent processing options, their management in use and, ultimately, the pathways and options for their recovery, reuse or disposal. Furthermore, the growing ubiquity of composite products means this urgently needs to be addressed by the sector.

This research sets out the current landscape for the use of LCA for CFRP composites focussing on identifying the existing gaps in knowledge and proposes a strategy to reduce the levels of uncertainty and variation in life cycle inventory (LCI) data for LCAs for CFRP composites. Using a range of manufacturing data from industrial and academic sources, a parametric model has been developed to calculate the EI of CF manufacture from polyacrylonitrile (PAN), accompanied by a set of alternative material and production scenarios that drive divergent outcomes. Consequentially, this approach presents a series of environmental data for CF production differentiated according to specified parameters, demonstrating the requirement for more detailed classification of CF types when discussed in terms of EI.

Concurrently, recognising that waste streams of CF or CFRP composite can be feedstock for CF product manufacture, another challenge for LCA concerns modelling the end of life (EOL) phase. This research also considered scenarios at this stage and initiates a framework for LCA on EOL processing options, identifying the specific barriers to the realisation of an effective supply chain for CF remanufacture.