Advancing prospective life cycle assessment -Experiences from guiding carbon fibre composite development
Doctoral thesis, 2023

Life cycle assessment is a powerful tool for quantifying the environmental impacts of goods and services. While most easily done for well-defined and known product systems, there is also a need for a prospective (that is, a future-orientated) approach to assessing developing technologies. This is because choices made in the early stages of technology development greatly influence the environmental impact of final product systems.
 
An increasingly popular range of materials on the market is carbon fibre composites, with a common application being in vehicles. The relatively light and strong carbon fibre composites can significantly reduce vehicles’ weight and, therefore, the impact of the use phase. However, carbon fibres are based on a fossil raw material and their production is highly energy-intensive. This means that if used in a vehicle, there may be no overall environmental benefit from a life cycle perspective. In fact, the use of carbon fibre composites might even increase the environmental impact of vehicles’ life cycles. Thus, the carbon fibre composite manufacturing process needs to be changed.
 
In this thesis, I present an environmental screening method to be used in the early stages of material development research projects when primary data is scarce. I also provide recommendations on how to allocate benefits and burdens between life cycles and co-products in prospective studies. Moreover, I reconceptualise the composite recycling process into a multi-output separation process, which leads to an allocation between both composite constituents and life cycles. I also provide three consistent future scenarios developed for carbon fibre composites. Finally, I include advice on how to compare immature to mature technologies in prospective life cycle assessments.

climate impact

Life cycle assessment

prospective

carbon fibre composites

energy use

Vasa C
Opponent: Prof. Jon McKechnie, Faculty of Engineering, Nottingham University, United Kingdom

Author

Frida Hermansson

Chalmers, Technology Management and Economics, Environmental Systems Analysis

Can carbon fiber composites have a lower environmental impact than fiberglass?

Resources, Conservation and Recycling,;Vol. 181(2022)

Journal article

Allocation in recycling of composites ‐ the case of life cycle assessment of products from carbon fiber composites

International Journal of Life Cycle Assessment,;Vol. 27(2022)p. 419-432

Journal article

Allocation in life cycle assessment of lignin

International Journal of Life Cycle Assessment,;Vol. 25(2020)p. 1620-1632

Journal article

We are currently facing a climate crisis. To mitigate this, we need to make sure that we replace technologies and products with high emissions with those with lower ones. But how can we know that the new technologies actually decrease the emissions? In this thesis, I use and develop the decision tool life cycle assessment for quantifying the environmental impacts of technologies and products. I focus specifically on the early stages of development when there is yet no large-scale production or market.
 
Although the work in this thesis is more generally applicable, focus is on carbon fibre composites, a light and strong material that can substitute heavier materials such as metals in, say, vehicles. However, carbon fibres are extremely energy-intensive to produce which is bad for the vehicle’s total environmental footprint. More technical development work is therefore needed to make sure that it makes sense environmentally to shift to carbon fibre composites.
 
One obvious challenge in future oriented life cycle assessments is the availability of production data. However, there are also challenges related to foreseeing future markets. As an example, something that is considered a waste today may very well be considered a valuable raw material in the future. Depending on choices made in the modelling, there is a large risk of generating results with large variations. In this thesis, I give advice on how to handle such challenges.

Lignin Based Carbon Fibres for Composites (LIBRE)

European Commission (EC) (EC/H2020/720707), 2016-11-01 -- 2020-10-31.

Driving Forces

Sustainable development

Areas of Advance

Transport

Energy

Subject Categories

Other Environmental Engineering

Environmental Management

ISBN

978-91-7905-974-3

Doktorsavhandlingar vid Chalmers tekniska högskola. Ny serie: 5440

Publisher

Chalmers

Vasa C

Online

Opponent: Prof. Jon McKechnie, Faculty of Engineering, Nottingham University, United Kingdom

More information

Latest update

12/20/2023