A meta-analysis of LCAs for environmental assessment of a conceptual system: Phosphorus recovery from dairy wastewater

A significant increase in phosphorus-rich dairy wastewater coincides with a decrease in the availability of fossil phosphate rock resources in Europe. This confluence of events has led to the development of technologies for phosphorus recovery from dairy wastewater. This study aims to inform and guide such development with regard to life cycle environmental impacts prior to their implementation in dairy contexts. With the lack of inventory data at this point and the non-existence of earlier life cycle assessments on the use of phosphorus recovery technologies in a dairy context in literature, we performed a meta-analysis where we extracted and compared published results on life cycle environmental impacts from two fields (1) dairy industries, with a focus on the dairy wastewater treatment and (2) phosphorus recovery technologies in a municipal wastewater treatment context. The results show that despite its intended effect, normal dairy wastewater treatment in many cases still contributes significantly to eutrophication. Most of the phosphorus recovery technologies examined here exhibited a lower global warming potential and cumulative energy demand than those of dairy wastewater treatment processes. It indicates that problem shifting could be avoided when phosphorus recovery is introduced. However, no technologies involving incineration have had the impact of acidification reported which represents a potential knowledge gap since impacts are expected related to incineration emissions. A comparison between the extracted data for phosphorus recovery technologies shows that there are lower impacts related to technologies that recover phosphorus from the liquid phase, than from sludge or ash

Prospective life cycle assessment for biorefinery concept development

One of the factors that the successful development of a bio-based economy depends on, is the development of novel biorefinery process concepts and technologies for the production of chemicals and materials. Besides being economically profitable, these concepts and technologies should also be environmentally benign. However, they are oftentimes still in the early phase of their development. Prospective life cycle assessment (LCA) aims at evaluating the future (or prospective) environmental performance of a product, process concept or technology during this phase of development, and methodological choices need to be made to achieve this.First, this presentation discusses several examples of LCAs with prospective elements related to biorefinery process development for the production of fuel, chemcials and materials. Next, a more general overview of recent advances in the field of prospective LCA, specifically with regards to the goal and scope definition and life cycle inventory steps, is given. For example, the generation of future foreground and background inventory data is discussed. Finally, a new approach is presented to incorporate future scenario development into prospective LCA. The goal of this approach is to, based on relevant parameters related to both the foreground and background systems, identify scenarios that represent a plausible future for a biorefinery process concept or technology. The outcomes of the assessments of these scenarios can then be used as a decision aid for further development. A prospective LCA on the production of carbon fibre will be used to exemplfy this approach

Lessons learned when assessing emerging composite materials using life cycle assessment

The modern era of carbon fibres and carbon fibre reinforced polymers (CFRPs) started in the mid 1950s as the U.S. air force Materials Laboratory started producing carbon fibres to develop high strength composites. However, the historically high cost of carbon fibres has until recently kept the use to a small range of applications [1]. It is not until recently that the use of CFRP has become widespread, consequently, CFRP should be considered an emerging material [2]. This makes the environmental assessment difficult as there is a lack of available production data. On the other hand, the emerging nature still makes technology changes possible. This mitchmatch between available data for assessment and production improvements is sometimes referred to as the Collingridge Dilemma. Collingridge described a paradox between information and control: impacts are hard to predict when technology is not yet fully developed, while change becomes more difficult when the technology develops [3].This paper aims to describe a multi-year effort to use life cycle assessment (LCA) for assessing the environmental impacts of emerging composite materials, focused on the specific example of CFRP. We will describe how we started with a meta-analysis to identify hotspots and key aspects for decreasing the environmental impacts of carbon fibres and CFRPs, to more recent efforts looking into possible future multifunctional use of CFRP for both light-weighting and energy storage in electric vehicles. Results focus on key insights and lessons learned in the process of assessing emerging composite materials using LCA as well as recommendations for decreasing the environmental impacts of carbon fibre composites

Assessing efforts to reduce the environmental impacts of carbon fibre composites in vehicles

This presentation will be about the life cycle assessment of different technology development routes for decreasing the environmental impacts of carbon fibre composites in vehicles. Three main routes were assessed: The use of bio-based raw materials for the fibre production, the use of microwave technology in fibre production, and the recycling of the composites and recovery of the fibres after use. The goal was to assess which of these routes that are more promising for making the environmental impacts of carbon fibre composites in vehicles environmentally competitive to glass fibre composites, what aspects that influence this comparison, and what remaining hot spots might be

A procedure for Prospective LCA in Materials Development - The Case of Carbon Fibre Composites

1. IntroductionLife cycle assessment is a powerful tool for quantifying the environmental impacts of products and services and is an essential part of product development. It can, for example, be used to identify hotspots to find ways to keep environmental impacts as small as possible. Assessing a product or service under development requires a prospective approach. A problem in prospective life cycle assessment (pLCA) is, however, the lack of data, which can lead to inconclusive results. The prospective context, however, also implies that there is still room for process changes and improvements [1]. This paper will present a work procedure for pLCA that grew out of a multi-year project aimed at developing lignin-based carbon fibres for composites (see LIBRE [2]). The intention with this contribution is to provide practitioners guidance on how LCAs in early stages of material development can be handled.2. Method:The development ofa work procedure for pLCAWhen starting the LIBRE project, there were no data available for the production of the fibres, and efforts needed to be made to: 1) identify hotspots in the life cycle of carbon fibre composites to show the possible influence of transitioning to a lignin-based fibre, and 2) identify other important routes for decreasing the environmental impact of the composite. This was then done by developing a meta-analysis framework for using results found in available literature on LCAs of carbon fibre reinforced polymers (CFRP) and of lignin production. The results found in the literature were carefully extracted and recalculated to the same functional unit to enable comparisons between studies. The meta-analysis found that a shift to lignin could decrease the environmental impact of carbon fibre composites, but that this is heavily dependent on the allocation approach used to allocate the impacts between co-products at a mill where the lignin is produced. The meta-analysis also identified recycling and recovery of fibres as promising, but that this also is very dependent on how allocation is handled, in this case allocation between life cycles [3].To explore the influence of the allocation approach for lignin production, allocation approaches found in literature were applied to a case study of the climate impact of lignin extracted from a Kraft pulp mill (see Hermansson et al. [4] for details). In addition, two new allocation approaches were developed: 1) considering the impacts from the lignin extraction process in a subdivision style approach, and 2) partitioning the impacts of the system between energy streams and material streams based on mass conversion, followed by either energy allocation (for energy streams) or mass allocation (for material streams). Results showed that the climate impact of the lignin is highly sensitive to the choice of allocation approach. As the intention was to apply the allocation approaches in a pLCA, they were assessed based on sensitivity to changes in demand for lignin, as this is an aspect of this specific system that could change much over time. The outcome was that many allocation approaches are sensitive to the temporal settings of the study, in particular with regard to prices and/or what is considered the main reason for lignin being extracted from the mill.The influence of allocation approaches in recycling of CFRP was also assessed in a case study. Different allocation approaches were redefined to handle the multiple outputs of both polymer and fibre from composite recycling. The redefined allocation approaches were applied to different fictitious recycling systems that employed different recycling methods. Results showed that the outcome of the assessment is highly dependent on the inherent incentives for recycling in the allocation approaches. For example: The cut- off approach provides no incentive to recycle the product, whereas the end-of-life recycling approach and the circular footprint formula (CFF) do. Recommendations were to, if possible, include both the end-of-life recycling approach and the cut-off approach as two extremes in pLCAs, as the result of the case study showed a large sensitivity to quality and demand for recycled carbon fibres. The CFF, which can be seen as a compromise between the two other allocation approaches but that is dependent on information on the supply and demand for secondary material and therefore challenging to apply in a prospective context, can then be avoided [5].When different technology routes and allocation approaches had been identified, the findings were applied in a case study of carbon fibre composites in road vehicles (see Hermansson et al. [6]). The technology routes were assessed both separately and grouped into coherent scenarios, as it is likely that some technology development routes will happen simultaneously [7]. By assessing them separately, the individual routes that are most promising for decreasing the environmental impact of the system could be identified. By assessing them together, it was possible to assess under which overarching conditions in society, for example due to aspects related to legislation or R&D funding, the environmental impact would be reduced the most. The end-result, where carbon fibre composites reduced the vehicles’ environmental impact in almost all futures [6], should be seen as an indication of the possible future environmental impacts of the system under study and can provide guidance to technology development.3. Results,Discussion, and ConclusionsThe work procedure that grew out of the work in the LIBRE project is visualized in Figure 1. The procedure proved useful for tackling the issue of lack of data in early stages of materials development and helped identifying key parameters in both the technical development and in the surrounding world that would have a large influence on the end result.Figure 1: The procedure for prospective life cycle assessment in materials development, which grew out of the context of assessing carbon-fibre compositesKey findings include the usefulness of mining and extracting LCA results from available literature to identify the most important parameters in early stages of materials developments. They also include recommendations on how allocation should be handled for both multi-output processes and recycling systems in pLCAs, also including some new options for multi-output processes. While the procedure was initially used and developed for assessing CFRP, we argue that it is likely applicable to many emerging technologies, especially when the assessment of these face the same types of difficulties in terms of data availability and uncertainties regarding changes to, for example, market demand and prices.4. References[1] Arvidsson, R., et al., Environmental Assessment of Emerging Technologies: Recommendations for Prospective LCA. Journal of Industrial Ecology, 2018. 22(6): p. 1286-1294.[2] LIBRE. LIBRE-Lignin Based Carbon Fibres for Composites. 2016 [cited 2018 9:th of november]; Available from: http://libre2020.eu.[3] Hermansson, F., M. Janssen, and M. Svanstr\uf6m, Prospective study of lignin-based and recycled carbon fibers in composites through meta-analysis of life cycle assessments. Journal of Cleaner Production, 2019. 223: p. 946-956.[4] Hermansson, F., M. Janssen, and M. Svanstr\uf6m, Allocation in life cycle assessment of lignin. The International Journal of Life Cycle Assessment, 2020.[5] Hermansson, F., et al., Allocation in recycling of composites - the case of life cycle assessment of products from carbon fiber composites. The International Journal of Life Cycle Assessment, 2022. 27(3): p. 419-432.[6] Hermansson, F., et al., Can carbon fiber composites have a lower environmental impact than fiberglass? Resources, Conservation and Recycling, 2022. 181: p. 106234.[7] Langkau, S. and M. Erdmann, Environmental impacts of the future supply of rare earths for magnet applications. Journal of Industrial Ecology, 2021. 25(4): p. 1034-1050.Acknowledgement - This project has received funding from the Bio Based Industries Joint Undertaking under the European Union’s Horizon 2020 research and innovation programme under grant agreement No 720707 and Chalmers University of Technology - Energy Area of Advance (ECE profile) Transport Area of Advance

Prospective study of lignin-based and recycled carbon fibers in composites through meta-analysis of life cycle assessments

Screening the life cycle assessment literature for information and recalculating extracted results was proven useful for identifying environmental challenges and opportunities in new, but related, contexts at early stages of technology development. The method was applied to carbon fiber reinforced polymers, a material of growing importance in industrial applications where a strong and/or light material is needed, such as in aircrafts and road vehicles. Many technology development efforts with the purpose of further improving such composite materials are on-going, in particular regarding the origin of carbon fibers. Using lignin as a bio-based feedstock and various recycling techniques have been suggested. However, these technologies do not yet exist at a scale that would enable a meaningful life cycle inventory, while the need for environmental guidance is urgent in order to ensure that only the more promising development paths are pursued before lock-in occurs. With a specific focus on the shift to lignin as a feedstock for carbon fibers and on recycled carbon fibers in composites, this article not only illustrates the type of information that can be obtained from mining and refining information from earlier life cycle assessment studies, but it also provides direct guidance on environmental opportunities and challenges specific for carbon fiber reinforced polymers. Thereby, it informs both technology development efforts and environmental assessment efforts. Amongst other things, the analysis reveals that an important factor behind the environmental impact of composites is the energy demand in carbonization of the carbon fibers and that both the shift to lignin-based and to recycled carbon fibers can potentially reduce this environmental impact. However, assessments of both lignin (as an output from a multifunctional process) and recycled carbon fibers (as an output from end-of-life activities) are connected to challenges related to the allocation of environmental impacts in an environmental assessment. Extracting and refining information from the literature proved useful for the specific task but remains to be tested in other fields of emerging technologie

Allocation in life cycle assessment of lignin

Purpose Lignin extraction in pulp mills and biorefineries are emerging technologies. Lignin is always the product of a multi- output process. Assessing such processes using life cycle assessment (LCA) requires the environmental impacts to be divided between the co-products of the system, referred to as allocation. This article explores different allocation approaches for lignin and illustrates the influence of the choice of allocation approach on the climate impact in a case study.Method Ten different applicable allocation methods were found in literature and two more were developed. Lignin production in a Kraft pulp mill using the LignoBoost process for lignin extraction was selected as a study object for the case study, and due to limited data availability only climate impact was considered. A cradle-to-gate LCA was done for the study object, and all of the twelve allocation approaches were applied; for eight of the methods, factors that strongly influence the results were identified and varied. Finally, the results were put in the context of cradle-to-grave LCAs from literature for different possible uses of lignin to give an indication of how important the choice of allocation approach can be when assessing lignin as a substitute for other raw materials.Results and discussion Results show that all allocation approaches tested were applicable to the special case of lignin, but each one of them comes with inherent challenges. Factors that often have a large impact on the results are (1) market and price of different outputs; (2) what is seen as the main product or the driver of the system or system changes; (3) what the surrounding system looks like and hence what other products will be displaced by outputs. These factors can be particularly challenging in prospective studies as such studies are future-oriented and consider systems that do not yet exist. Finally, the results show that the choice of allocation could have a significant influence on the climate impact on the cradle-to-grave climate impact of the final product.Conclusions We recommend for LCAs of lignin-based technologies that allocation methods are very carefully selected based on the goal and scope of the study and that when relevant, several methods are applied and factors are varied within them in a sensitivity analysis. In particular, the driver(s) of the system’s existence or of changes to it, sometimes reflected in market prices of outputs, should be carefully considered

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

Purpose Composites consist of at least two merged materials. Separation of these components for recycling is typically an energy-intensive process with potentially significant impacts on the components’ quality. The purpose of this article is to suggest how allocation for recycling of products manufactured from composites can be handled in life cycle assessment to accommodate for the recycling process and associated quality degradations of the different composite components, as well as to describe the challenges involved.Method Three prominent recycling allocation approaches were selected from the literature: the cut-off approach, the end- of-life recycling approach with quality-adjusted substitution, and the circular footprint formula. The allocation approaches were adapted to accommodate for allocation of impacts by conceptualizing the composite material recycling as a separation process with subsequent recycling of the recovered components, allowing for separate modeling of the quality changes in each individual component. The adapted allocation approaches were then applied in a case study assessing the cradle- to-grave climate impact and energy use of a fictitious product made from a composite material that in the end of life is recycled through grinding, pyrolysis, or by means of supercritical water treatment. Finally, the experiences and results from applying the allocation approaches were analyzed with regard to what incentives they provide and what challenges they come with.Results and discussion Using the approach of modeling the composite as at least two separate materials rather than one helped to clarify the incentives provided by each allocation approach. When the product is produced using primary materials, the cut-off approach gives no incentive to recycle, and the end-of-life recycling approach and the circular footprint formula give incentives to recycle and recover materials of high quality. Each of the allocation approaches come with inherent challenges, especially when knowledge is limited regarding future systems as in prospective studies. This challenge is most evident for the circular footprint formula, for example, with regard to the supply and demand balance.Conclusions We recommend modeling the composite materials in products as separate, individual materials. This proved useful for capturing changes in quality, trade-offs between recovering high quality materials and the environmental impact of the recycling system, and the incentives the different approaches provide. The cut-off and end-of-life approaches can both be used in prospective studies, whereas the circular footprint formula should be avoided as a third approach when no market for secondary material is established

Prospective, Anticipatory and Ex-Ante – What’s the Difference? Sorting Out Concepts for Time-Related LCA

Most life cycle assessment (LCA) studies have considered technologies as they are at the time of the study, often in a mature state. Increasingly, LCA studies attempt to assess emerging technologies in imagined states at future points in time, often referred to as prospective, anticipatory or ex-ante. However, a clear distinction between these LCA types is lacking. We aim to sort these concepts into a typology of time-related LCAs, contributing to more purposeful methodological choices. Existing frameworks for time-realted LCA types were reviewed and typology consisting of three dimensions was found to capture the most important differences. The first dimension is real time, which captures the time difference between the functional unit and the LCA. If the technology is modelled at approximately the same time as when the LCA is conducted, it can be called contemporary LCA. If the technology is modelled at a future point in time relative to the analysis, it can be called prospective LCA, and retrospective LCA if it is modelled at a past point in time relative to the study. Dynamic LCA accounts for that a technology can be “stretched out” along the real time dimension. The second dimension is technology maturity, which can be measured by technology readiness levels (TRLs). Ex-ante LCA considers technologies that are immature at the time of the study but model them in a future when they are assumed to have become mature, and is thus a specific type of prospective LCA. In contrast, ex-post LCA refers to studies of technologies that have reached maturity at the time of the study. Anticipatory LCA is effectively similar to ex-ante LCA but also entails the inclusion of numerous stakeholders in shaping the LCA study. Lab-scale LCA is a contemporary LCA of an immature technology with the aim of suggesting improvements to technology developers. The third dimension is causality. Some LCA studies mainly consider causes of a functional unit, which is often referred to as attributional LCA. Other LCA studies mainly consider effects of a functional unit, which can be called consequential LCA. While the former can be said to look backwards in time, the latter can be said to look forward in time from the perspective of the functional unit. Both types can, however, be retrospective, contemporary, or prospective LCAs as defined above. It is also possible to consider different types of causality, which relate differently to real time and technology maturity

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

Carbon fiber composites are increasingly used to decrease fuel consumption in the use phase of vehicles. However, due to the energy intensive production, the reduced fuel consumption may not lead to life cycle environmental savings as much as for other lightweighting materials, for example fiberglass. This study uses life cycle assessment methodology to assess how different future development routes including using bio-based raw materials, microwave technology, and recycling of composites with the recovery of fibers influence the envi- ronmental impact of both carbon fiber composites and fiberglass in vehicles. Results show that combining different development routes could lead to carbon fiber composites with a lower environmental impact than fiberglass composites in the future and that recycling of composites with recovery of fibers is the route that alone shows the greatest potential