Life cycle environmental and economic assessment of industrial symbiosis networks: a review of the past decade of models and computational methods through a multi-level analysis lens

Purpose

Industrial symbiosis network (ISN) facilitation tools seek to holistically evaluate the environmental and economic performance of ISNs through life cycle assessment (LCA) and life cycle costing (LCC). ISNs have many stakeholders with diverse interests in the LCA and LCC results thus requiring multi-level analysis. The objective of this review was to examine the state-of-the-art methodologies used in LCAs and LCCs of ISNs and understand how multi-level analysis can be conducted.

Methods

The systematic literature review methodology was applied to develop a corpus of peer-reviewed LCA and LCC studies of ISNs published between 2010 and 2019 without any geographic boundary. Abstracts were reviewed to shortlist studies that conducted an LCA or LCC of an ISN with numerical results. LCA and LCC methodologies used in the shortlisted studies were collected and categorized. Each methodology was examined to understand how the foreground and background systems are represented, how waste-to-resource exchanges are analyzed, and how the results can be computed at the network, entity, and flow levels.

Results and discussion

The review yielded 42 LCA studies and 11 LCC studies of ISNs that used eight different methodologies. Process-based LCA was used in 71% of the LCA studies, whereas tiered hybrid LCA was used in 14% of the studies. Waste-to-resource exchanges in ISN scenarios were represented either through process analysis or as a black box. Fewer LCC studies that evaluate the economic performance of ISNs exist compared with LCA studies. Economic studies often evaluated financial feasibility, net present value, profitability, or payback period of specific waste-to-resource exchanges or the network overall.

Conclusions

The insights derived from this review chart future areas of research in multi-level modeling and analysis of the life cycle environmental and economic performance of ISNs. To improve the model construction and analysis process, research should be explored in developing a methodology for constructing a single model that represents multiple entities linked together by waste-to-resource exchanges and can provide LCA and LCC results for different stakeholder perspectives. The lack of LCC studies of ISNs merits the need for more research in this area at both the network and entity levels to quantify potential economic trade-offs between stakeholders. Developing a methodology for unified LCA and LCC modeling and analysis of ISNs can help ISN facilitation tool developers conduct simultaneous life cycle environmental and economic analysis of the potential symbiosis connections identified and how they contribute to the overall network.

     

An integrated environment and cost assessment method based on LCA and LCC for mechanical product manufacturing

Purpose

The purpose of this study is to provide an integrated method to identify the resource consumption, environmental emission, and economic cost for mechanical product manufacturing from economic and ecological dimensions and ultimately to provide theoretical and data support of energy conservation and emission reduction for mechanical product manufacturing.

Methods

The applied research methods include environmental life cycle assessment (LCA) and life cycle cost (LCC). In life cycle environmental assessment, the inventory data are referred from Chinese Life Cycle Database and midpoint approach and EDIP2003 and CML2001 models of life cycle impact assessment (LCIA) are selected. In life cycle cost assessment, three cost categories are considered. The proposed environment and cost assessment method is based on the theory of social willingness to pay for potential environmental impacts. With the WD615 Steyr engine as a case, life cycle environment and cost are analyzed and evaluated.

Results and discussion

The case study indicates that, in different life cycle phases, the trend of cost result is generally similar to the environmental impacts; the largest proportion of cost and environmental impact happened in the two phases of “material production” and “component manufacturing” and the smallest proportion in “material transport” and “product assembly.” The environmental impact category of Chinese resource depletion potential (CRDP) accounted for the largest proportion, followed by global warming potential (GWP) and photochemical ozone creation potential (POCP), whereas the impacts of eutrophication potential (EP) and acidification potential (AP) are the smallest. The life cycle “conventional cost” accounted for almost all the highest percentage in each phase (except “material transport” phase), which is more than 80% of the total cost. The “environmental cost” and “possible cost” in each phase are relatively close, and the proportion of which is far below the “conventional cost.”

Conclusions

The proposed method enhanced the conventional LCA. The case results indicate that, in a life cycle framework, the environment and cost analysis results could support each other, and focusing on the environment and cost analysis for mechanical product manufacturing will contribute to a more comprehensive eco-efficiency assessment. Further research on the life cycle can be extended to phases of “early design,” “product use,” and “final disposal.” Other LCIA models and endpoint indicators are advocated for this environmental assessment. Environmental cost can also be further investigated, and the relevant social willingness to pay for more environmental emissions is advocated to be increased.

     

Performance and environmental accounting of nutrient cycling models to estimate nitrogen emissions in agriculture and their sensitivity in life cycle assessment

Purpose

Several models are available in the literature to estimate agricultural emissions. From life cycle assessment (LCA) perspective, there is no standardized procedure for estimating emissions of nitrogen or other nutrients. This article aims to compare four agricultural models (PEF, SALCA, Daisy and Animo) with different complexity levels and test their suitability and sensitivity in LCA.

Methods

Required input data, obtained outputs, and main characteristics of the models are presented. Then, the performance of the models was evaluated according to their potential feasibility to be used in estimating nitrogen emissions in LCA using an adapted version of the criteria proposed by the United Nations Framework Convention on Climate Change (UNFCCC), and other relevant studies, to judge their suitability in LCA. Finally, nitrogen emissions from a case study of irrigated maize in Spain were estimated using the selected models and were tested in a full LCA to characterize the impacts.

Results and discussion

According to the set of criteria, the models scored, from best to worst: Daisy (77%), SALCA (74%), Animo (72%) and PEF (70%), being Daisy the most suitable model to LCA framework. Regarding the case study, the estimated emissions agreed to literature data for the irrigated corn crop in Spain and the Mediterranean, except N₂O emissions. The impact characterization showed differences of up to 56% for the most relevant impact categories when considering nitrogen emissions. Additionally, an overview of the models used to estimate nitrogen emissions in LCA studies showed that many models have been used, but not always in a suitable or justified manner.

Conclusions

Although mechanistic models are more laborious, mainly due to the amount of input data required, this study shows that Daisy could be a suitable model to estimate emissions when fertilizer application is relevant for the environmental study. In addition, and due to LCA urgently needing a solid methodology to estimate nitrogen emissions, mechanistic models such as Daisy could be used to estimate default values for different archetype scenarios.

     

Perceived uncertainties of characterization in LCA: a survey

Purpose

Uncertainty analyses in life cycle assessment (LCA) literature have focused primarily on the life cycle inventory (LCI) phase, but LCA experts generally agree that the life cycle impact assessment (LCIA) phase is likely to contribute even more to the overall uncertainty of an LCA result. The magnitude of perceived uncertainties in characterization relative to that in LCI, however, has not been examined in the literature. Here, we use the pedigree approach to gauge the perceived uncertainty in the characterization phase relative to the LCI phase. In addition, we evaluate the level of approval on the pedigree approach as a means to characterize uncertainty in LCA.

Methods

Applying the Numeral Unit Spread Assessment Pedigree (NUSAP) approach to environmental risk assessment literature, we extracted the criteria for evaluating the uncertainty in the characterization phase. We used expert elicitation to identify a pool of experts and conducted a survey, to which 47 LCA practitioners from 12 countries responded. In order to reduce personal biases in perceived geometric standard deviation (GSD) values, we used two reference questions on weight and life expectancy at birth for calibration.

Results

Nearly half (49%) of respondents expressed their approval to the pedigree matrix approach as a means of characterizing uncertainties in LCA, and responses were highly sensitive to the respondent’s familiarity with the pedigree matrix. For instance, respondents who are highly familiar with the pedigree matrix were more polarized, with 15% and 19% of them expressing either strong approval or strong disapproval, respectively. Respondents less familiar with the pedigree approach were generally more favorable to its use. Compared with LCI, variability in characterization factors was influenced more strongly by geographical correlation and reliability of the underlying model, which showed 11 to 16% larger average GSDs when compared with the comparable criteria for LCI. Conversely, temporal correlation criterion was a less significant factor in characterization than in LCI.

Conclusions and discussion

Overall, survey respondents viewed LCIA characterization as only marginally more uncertain than LCI, but with a wider variability in responses on characterization than LCI. This finding indicates the need for additional research to develop more thorough methods for characterizing uncertainties in life cycle impact assessment that are compatible with the uncertainty measures in LCI.

     

The implementation of organizational LCA to internally manage the environmental impacts of a broad product portfolio: an example for a cosmetics,fragrances, and toiletry provider

Purpose

This paper presents the implementation of O-LCA by a Brazilian cosmetics manufacturer. The case study was developed within the framework of the road testing of the “Guidance on organizational LCA” of the UNEP/SETAC Life Cycle Initiative. The aim is to illustrate methodological choices and implementation challenges encountered by the company, i.e., related to the broad product portfolio. The study demonstrates that O-LCA allows quantifying and managing environmental impacts throughout global supply chains and for every individual product.

Methods

O-LCA provides the methodological framework for applying LCA to organizations, and a set of application options based on the structure and experience of organizations. The reporting organization is NATURA Brazil in 2013. The 2600 products in the portfolio are modeled in this first exercise of the company through the bestsellers at each of its ten product category groups. A hybrid approach is considered for data collection: top-down approach for modeling corporate activities and bottom-up approach for upstream and downstream life cycle phases. The data sources are NATURA’s recordings, data gathered from suppliers, estimates from mass and energy balances, and life cycle inventory databases. The approach to acquire direct data or use life cycle databases depends on the representativeness of each raw material or packaging.

Results and discussion

The results show that major impacts could be detected during use phase that demands water and energy to use rinse-off products (the use phase of NATURA’s products contributed over 41% to most impact categories), and in the supply chain, and generated during the obtaining of plant origin ingredients and materials for packaging. Overall, the whole NATURA had in 2013 a potential impact on climate change of 1.4 million tonnes of CO₂ eq, a natural land transformation of 1.3 million m², and a fossil depletion of 0.23 million tonnes of oil eq, among other impacts. Apart from the results at the organizational level, individual results for product bestsellers were calculated and are presented here.

Conclusions

The study confirmed the applicability of the O-LCA model at NATURA, addressed operational issues related to broad product portfolios, considering several dimensions such as data quality and availability, LCA software, and data management. Despite NATURA’s existing practices and previous knowledge in modeling environmental impacts of products and corporate activities, managing the large amount of data involved prove being a complex task. The company identified gaps and opportunities able to guide future method implementation and LCA-based management.

     

Environmental assessment of multi-functional building elements constructed with digital fabrication techniques

Purpose

Digital fabrication is revolutionizing architecture, enabling the construction of complex and multi-functional building elements. Multi-functionality is often achieved through material reduction strategies such as functional or material hybridization. However, these design strategies may increase environmental impacts over the life cycle. The integration of functions may hinder the maintenance and shorten the service life. Moreover, once a building element has reached the end of life, hybrid materials may influence negatively its recycling capacity. Consequently, the aim of this paper is to analyze the influence of multi-functionality in the environmental performance of two digitally fabricated architectural elements: The Sequential Roof and Concrete-Sandstone Composite Slab and to compare them with existing standard elements.

Methods

A method based on the life-cycle assessment (LCA) framework is applied for the evaluation of the environmental implications of multi-functionality in digital fabrication. The evaluation consists of the comparison of embodied impacts between a multi-functional building element constructed with digital fabrication techniques and a conventional one, both with the same building functions. Specifically, the method considers the lifetime uncertainty caused by multi-functionality by considering two alternative service life scenarios during the evaluation of the digitally fabricated building element. The study is extended with a sensitivity analysis to evaluate the additional environmental implications during end-of-life processing derived from the use of hybrid materials to achieve multi-functionality in architecture.

Results and discussion

The evaluation of two case studies of digitally fabricated architecture indicates that their environmental impacts are very sensitive to the duration of their service life. Considering production and life span phases, multi-functional building elements should have a minimum service life of 30 years to bring environmental benefits over conventional construction. Furthermore, the case study of Concrete-Sandstone Composite Slab shows that using hybrid materials to achieve multi-functionality carries important environmental consequences at the end of life, such as the emission of air pollutants during recycling.

Conclusions

The results from the case studies allow the identification of key environmental criteria to consider during the design of digitally fabricated building elements. Multi-functionality provides material efficiency during production, but design adaptability must be a priority to avoid a decrease in their environmental performance. Moreover, the high environmental impacts caused by end-of-life processing should be compensated during design.

     

Characterisation of social impacts in LCA

Background, aim, and scope  

The authors have suggested earlier a framework for life cycle impact assessment to form the modelling basis of social LCA. In this framework, the fundamental labour rights were pointed out as obligatory issues to be addressed, and protection and promotion of human dignity and well-being as the ultimate goal and area of protection of social LCA. The intended main application of this framework for social LCA was to support management decisions in companies who wish to conduct business in a socially responsible manner, by providing information about the potential social impacts on people caused by the activities in the life cycle of a product. Environmental LCA normally uses quantitative and comparable indicators to provide a simple representation of the environmental impacts from the product lifecycle. This poses a challenge to the social LCA framework because due to their complexity, many social impacts are difficult to capture in a meaningful way using traditional quantitative single-criterion indicators. A salient example is the violation of fundamental labour rights (child labour, discrimination, freedom of association, and right to organise and collective bargaining, forced labour). Furthermore, actual violations of these rights somewhere in the product chain are very difficult to substantiate and hence difficult to measure directly.     

Variable impact transportation (VIT) model for energy and environmental impact of hauling truck operation

Purpose

Fuel economy and emissions of heavy-duty trucks greatly vary based on vehicular/environmental conditions. Large-scale infrastructure construction projects require a large amount of material/equipment transportation. Single-parameter generic hauling models may not be the best option for an accurate estimation of hauling contribution in life cycle assessment (LCA) involving construction projects; therefore, more precise data and parameterized models are required to represent this contribution. This paper discusses key environmental/operational variables and their impact on transportation of materials and equipment; a variable-impact transportation (VIT) model accounting for these variables was developed to predict environmental impacts of hauling.

Methods

The VIT model in the form of multi-nonlinear regression equations was developed based on simulations using the U.S. Environmental Protection Agency (EPA)’s Motor Vehicle Emission Simulator (MOVES) to compute all the impact categories in EPA’s TRACI 2.1 and energy consumption of transportation. Considering actual driving cycles of hauling trucks recorded during a pavement rehabilitation project, the corresponding environmental impacts were calculated, and sensitivity analyses were performed. In addition, an LCA case study based on historical pavement reconstruction projects in Illinois was conducted to analyze the contribution of transportation and variability of its impacts during the pavements’ life cycle.

Results and discussion

The importance of vehicle driving cycles was realized from simulation results. The case study results showed that considering driving cycles using the VIT model could increase the contribution of hauling in total life cycle Global Warming Potential (GWP) and total life cycle GWP itself by 2–4 and 3–5%, respectively. In addition to GWP, ranges of other hauling-related impact categories including Smog, Ozone Depletion, Acidification, and Primary Energy Demand from fuel were presented based on the case study. Ozone Depletion ranged from 9 to 45%, and Smog ranged from 11 to 48% of the total relevant life cycle impacts. The GWP contribution of hauling in pavement LCA ranged between 5 and 32%. The results indicate that the contribution of hauling transportation can be significant in pavement LCA.

Conclusions

For large-scale roadway infrastructure construction projects that need a massive amount of material transportation, high fidelity models and data should be used especially for comparative LCAs that can be used as part of decision making between alternatives. The VIT model provides a simple analytical platform to include the critical vehicular/operational variables without any dependence on an external software; the model can also be incorporated in those studies where some of the transportation activity data are available.

     

Integrating life cycle assessment (LCA) and life cycle costing (LCC) in the early phases of aircraft structural design: an elevator case study

Purpose

The main objective of this paper is to develop a model that will combine economic and environmental assessment tools to support the composite material selection of aircraft structures in the early phases of design and application of the tool for an aircraft elevator.

Methods

An integrated life cycle cost (LCC) and life cycle assessment (LCA) methodology was used as part of the sustainable design approach for the laminate stacking sequence design. The model considered is the aircraft structure made of carbon fiber reinforce plastic prepreg and processed via hand layup-autoclave process which is the preferred method for the aircraft industry. The model was applied to a cargo aircraft elevator case study by comparing six different laminate configurations and two different carbon fiber prepreg materials across aircraft’s entire life cycle.

Results and discussion

The results show, in line with other studies using different methodologies (e.g., life cycle engineering, or LCE), that the combination of LCA with LCC is a worthwhile approach for comparing the different laminate configurations in terms of cost and environmental impact to support composite laminate stacking design by providing the best trade-off between cost and environment. Elevator LCC reduces 19% by changing the material type and applying different ply orientations. Elevator LCA score reduces 53% by selecting the optimum instead of best technical solution that minimizes the displacement. Improving the structural performance does not always lead to an increase in the cost.

     

Social life cycle assessment: in pursuit of a framework for assessing wood-based products from bioeconomy regions in Germany

Purpose

With many policies in Germany steering towards a bioeconomy, there is a need for analytical tools that assess not only the environmental and economic implications but also the social implications of a transition to a bioeconomy. Wood is expected to become a major biomass resource in bioeconomy regions. Therefore, this paper develops a social life cycle assessment (sLCA) framework that can be applied specifically to a wood-based production system in one of Germany’s bioeconomy regions.

Methods

This paper reviews and analyses existing sLCA approaches, in terms of how applicable they are for assessing a wood-based production system in a German bioeconomy regional context. The analysis is structured according to the standard phases of environmental life cycle assessment (LCA). However, we use the term social effects rather than social impacts, to acknowledge the unknown cause–effect relationship between an organisation’s activities and its social impacts. We also consider the establishment of regional system boundaries, as well as the relationship between the social effects and the product being assessed. Additionally, an approach for the development and selection of social indicators and indices is outlined. Furthermore, we discuss data requirements and present an approach for a social life cycle impact assessment method.

Results and discussion

A new conceptual framework for a context-specific sLCA to assess wood-based products manufactured in a bioeconomy region was developed. It enables sLCA practitioners to identify “social hotspots” and “social opportunities” from a regional perspective. The location and characteristics of these social hotspots and opportunities can be analysed, in particular, for major production activities in a bioeconomy region in Germany. Therefore, according to this framework, the development of social indices and indicators, the collection of data and the approach used for characterising social effects need to relate to the geographical context of the product being assessed. The proposed framework can, thus, help to identify, monitor and evaluate the social sustainability of wood-based bioeconomy chains in a regional context.

Conclusions

This framework requires a high level of detail in the social inventory and impact assessment phase, in order to assess the regional foreground activities in a German wood-based bioeconomy region. It enables sLCA studies to identify which social hotspots and social opportunities occur and where they are located in the wood-based production system of a regional bioeconomy.

     

Life-LCA: assessing the environmental impacts of a human being—challenges and perspectives

Purpose

The life-cycle assessment (LCA) method is typically applied to products, but the potential and demand for extending its use also to other applications are high. In this respect, this paper proposes an LCA concept to be used for the assessment of human beings as new study objects, namely Life-LCA. Key challenges of such a new approach and potential solutions for those are identified and discussed.

Methods

The Life-LCA concept was developed based on a detailed desktop research. Several Life-LCA-specific challenges were identified and categorized under three research questions. One of these questions focusses on the conceptual design of a Life-LCA method while the others are addressing operational issues, which are the definition of the new study system and the practical assessment of complex human consumption behaviors. Methodological solutions are proposed, e.g., based on suggestions provided in the existing methods product LCA and organizational LCA (O-LCA).

Results and discussion

Conceptual challenges arise from the general diversity, complexity, and temporal development of human lives and consumption behaviors. We introduce Life-LCA as a two-dimensional method that covers both, the new human life cycle (dimension 1) and the life cycle of the consumed products (dimension 2). Furthermore, the two types Individual Life-LCA and Lifestyle-LCA are differentiated. Especially, the definition of a general system boundary for Life-LCA and data collection and evaluation face many operational challenges. For example, the social behavior of human beings is a new factor to be considered which causes new allocation problems in LCA. Moreover, the high demand for aggregated LCA data requires specific rules for data collection and evaluation as well as a new bottom-up product clustering scheme.

Conclusions

Life-LCA, either used for the assessment of individual lives or lifestyles, has the potential to raise environmental awareness of people by making their specific environmental impacts comprehensively measurable and thus, tangible. However, many challenges need to be solved in future interdisciplinary research to develop a robust and applicable method. This paper conceptualizes such an approach and proposes solutions that can serve as a framework for ongoing method development.

     

Environmental impacts of European trade: interpreting results of process-based LCA and environmentally extended input–output analysis towards hotspot identification

Purpose

Trade is increasingly considered a significant contributor to environmental impacts. The assessment of the impacts of trade is usually performed via environmentally extended input–output analysis (EEIOA). However, process-based life cycle assessment (LCA) applied to traded goods allows increasing the granularity of the analysis and may be essential to unveil specific impacts due to traded products.

Methods

This study assesses the environmental impacts of the European trade, considering two modelling approaches: respectively EEIOA, using EXIOBASE 3 as supporting database, and process-based LCA. The interpretation of the results is pivotal to improve the robustness of the assessment and the identification of hotspots. The hotspot identification focuses on temporal trends and on the contribution of products and substances to the overall impacts. The inventories of elementary flows associated with EU trade, for the period 2000–2010, have been characterized considering 14 impact categories according to the Environmental Footprint (EF2017) Life Cycle Impact Assessment method.

Results and discussion

The two modelling approaches converge in highlighting that in the period 2000–2010: (i) EU was a net importer of environmental impacts; (ii) impacts of EU trade and EU trade balance (impacts of imports minus impacts of exports) were increasing over time, regarding most impact categories under study; and (iii) similar manufactured products were the main contributors to the impacts of exports from EU, regarding most impact categories. However, some results are discrepant: (i) larger impacts are obtained from IO analysis than from process-based LCA, regarding most impact categories, (ii) a different set of most contributing products is identified by the two approaches in the case of imports, and (iii) large differences in the contributions of substances are observed regarding resource use, toxicity, and ecotoxicity indicators.

Conclusions

The interpretation step is crucial to unveil the main hotspots, encompassing a comparison of the differences between the two methodologies, the assumptions, the data coverage and sources, the completeness of inventory as basis for impact assessment. The main driver for the observed divergences is identified to be the differences in the impact intensities of goods, both induced by inherent properties of the IO and life cycle inventory databases and by some of this study’s modelling choices. The combination of IO analysis and process-based LCA in a hybrid framework, as performed in other studies but generally not at the macro-scale of the full trade of a country or region, appears a potential important perspective to refine such an assessment in the future.

     

Comparative life cycle assessment of car disc brake systems—case study results and method discussion about comparative LCAs

Purpose

Two life cycle assessment (LCA) studies comparing a new low-particulate-matter-emission disc brake and a reference disc brake were presented. The purpose was to identify the difference in potential environmental impacts due to a material change in the new disc brake parts. Additionally, the validity was investigated for the simplification method of omitting identical parts in comparative LCA. This was done by comparing the results between the simplified and the full LCA model.

Methods

The two disc brakes, new disc brake and reference disc brake, were assessed according to the LCA ISO standards. The ReCiPe 2016 Midpoint (hierarchist) impact assessment method was chosen. Simplifying a comparative LCA is possible, all identical parts can be omitted, and only the ones that differ need to be assessed. In this paper, this simplification was called comparative LCA with an omission of identical parts.

Results and discussion

The comparative impacts were analysed over seventeen impact categories. The new disc brake alternative used more resources during the manufacture of one disc compared to the reference disc brake alternative. The shorter life length of the reference disc demanded a higher number of spare part discs to fulfil the same functional unit, but this impact was reduced due to material recycling. The new disc brake impacts were connected primarily to the coating and secondly to the pad manufacture and materials. The validity of the simplification method was investigated by comparing the results of the two LCA models. The impact differences were identical independent of the LCA model, and the same significant impact categories could be identified. Hence, the purpose of the study could be fulfilled, and the simplification was valid.

Conclusions

Both LCA models, simplified and full, revealed that the new disc brake had limited environmental advantages. The omission of identical parts made it more challenging to determine if an impact was significant or insignificant. The simplification seemed to be reasonable.

     

Are there infinitely many trucks in the technosphere,or exactly one? How independent sampling of instances of unit processes affects uncertainty analysis in LCA

Purpose

Product systems use the same unit process models to represent distinct but similar activities. This notably applies to activities in cyclic dependency relationships (or “feedback loops”) that are required an infinite number of times in a product system. The study aims to test the sensitivity of uncertainty results on the assumption made concerning these different instances of the same activities. The default assumption assumes homogeneous production, and the same parameter values are sampled for all instances (e.g., there is one truck). The alternative assumption is that every instance is distinct, and parameter values are independently sampled for different instances of unit processes (e.g., there are infinitely many trucks). Intuitively, sampling the same values for each instance of a unit process should result in more uncertain results.

Methods

The results of uncertainty analyses carried out under either assumption are compared. To simulate models where each instance of a unit process is independent, we convert network models to acyclic LCI models (tree models). This is done three times: (1) for a very simple product system, to explain the methodology; (2) for a sample product system from the ecoinvent database, for illustrative purposes; and (3) for thousands of product systems from ecoinvent databases.

Results and discussion

The uncertainty of network models is indeed greater than that of corresponding tree models. This is shown mathematically for the analytical approximation method to uncertainty propagation and is observed for Monte Carlo simulations with very large numbers of iterations. However, the magnitude of the difference in indicators of dispersion is, for the ecoinvent product systems, often less than a factor of 1.5. In few extreme cases, indicators of dispersion are different by a factor of 4. Monte Carlo simulations with smaller numbers of iterations sometimes give the opposite result.

Conclusions

Given the small magnitude of the difference, we believe that breaking away from the default approach is generally not warranted. Indeed, (1) the alternative approach is not more robust, (2) the current default approach is conservative, and (3) there are more pressing challenges for the LCA community to meet. This being said, the study focused on ecoinvent, which should normally be used as a background database. The difference in dispersion between the two approaches may be important in some contexts, and calculating the uncertainty of tree models as a sensitivity analysis could be useful.

     

The environmental impact of packaging in food supply chains—does life cycle assessment of food provide the full picture?

Purpose

Due to the urgency and the magnitude of the environmental problems caused by food supply chains, it is important that the recommendations for packaging improvements given in life cycle assessment (LCA) studies of food rest on a balanced consideration of all relevant environmental impacts of packaging. The purpose of this article is to analyse the extent to which food LCAs include the indirect environmental impact of packaging in parallel to its direct impact. While the direct environmental impact of food packaging is the impact caused by packaging materials’ production and end-of-life, its indirect environmental impact is caused by its influence on the food product’s life cycle, e.g. by its influence on food waste and on logistical efficiency.

Methods

The article presents a review of 32 food LCAs published in peer-reviewed scientific journals over the last decade. The steps of the food product’s life cycle that contribute to the direct and indirect environmental impacts of packaging provide the overall structure of the analytical framework used for the review. Three aspects in the selected food LCAs were analysed: (1) the defined scope of the LCAs, (2) the sensitivity and/or scenario analyses and (3) the conclusions and recommendations.

Results and discussion

While in packaging LCA literature, there is a trend towards a more systematic consideration of the indirect environmental impact of packaging, it is unclear how food LCAs handle this aspect. The results of the review show that the choices regarding scope and sensitivities/scenarios made in food LCAs and their conclusions about packaging focus on the direct environmental impact of packaging. While it is clear that not all food LCAs need to analyse packaging in detail, this article identifies opportunities to increase the validity of packaging-related conclusions in food LCAs and provides specific recommendations for packaging-related food LCA methodology.

Conclusions

Overall, we conclude that the indirect environmental impact of packaging is insufficiently considered in current food LCA practice. Based on these results, this article calls for a more systematic consideration of the indirect environmental impact of packaging in future food LCAs. In addition, it identifies a need for more packaging research that can provide the empirical data that many food LCA practitioners currently lack. In particular, LCA practitioners would benefit if there were more knowledge and data available about the influence of certain packaging characteristics (e.g. shape, weight and type of material) on consumer behaviour.

     

Reviewing the potential for including habitat fragmentation to improve life cycle impact assessments for land use impacts on biodiversity

Purpose

The biosphere is progressively subjected to a variety of pressures resulting from anthropogenic activities. Habitat conversion, resulting from anthropogenic land use, is considered the dominant factor driving terrestrial biodiversity loss. Hence, adequate modelling of land use impacts on biodiversity in decision-support tools, like life cycle assessment (LCA), is a priority. State-of-the-art life cycle impact assessment (LCIA) characterisation models for land use impacts on biodiversity translate natural habitat transformation and occupation into biodiversity impacts. However, the currently available models predominantly focus on total habitat loss and ignore the spatial configuration of the landscape. That is, habitat fragmentation effects are ignored in current LCIAs with the exception of one recently developed method.

Methods

Here, we review how habitat fragmentation may affect biodiversity. In addition, we investigate how land use impacts on biodiversity are currently modelled in LCIA and how missing fragmentation impacts can influence the LCIA model results. Finally, we discuss fragmentation literature to evaluate possible methods to include habitat fragmentation into advanced characterisation models.

Results and discussion

We found support in available ecological literature for the notion that habitat fragmentation is a relevant factor when assessing biodiversity loss. Moreover, there are models that capture fragmentation effects on biodiversity that have the potential to be incorporated into current LCIA characterisation models.

Conclusions and recommendations

To enhance the credibility of LCA biodiversity assessments, we suggest that available fragmentation models are adapted, expanded and subsequently incorporated into advanced LCIA characterisation models and promote further efforts to capture the remaining fragmentation effects in LCIA characterisation models.

     

A framework for implementing holistic and integrated life cycle sustainability assessment of regional bioeconomy

Purpose

Currently, social, environmental, and economic risks and chances of bioeconomy are becoming increasingly a subject of applied sustainability assessments. Based on life cycle assessment (LCA) methodology, life cycle sustainability assessment (LCSA) aims to combine or integrate social, environmental, and economic assessments. In order to contribute to the current early stage of LCSA development, this study seeks to identify a practical framework for integrated LCSA implementation.

Methods

We select possible indicators from existing suitable LCA and LCSA approaches as well as from the literature, and allocate them to a sustainability concept for holistic and integrated LCSA (HILCSA), based on the Sustainable Development Goals (SDGs). In order to conduct a practical implementation of HILCSA, we choose openLCA, because it offers the best current state and most future potential for application of LCSA. Therefore, not only the capabilities of the software and databases, but also the supported methods of life cycle impact assessments (LCIA) are evaluated regarding the requirements of the indicator set and goal and scope of future case studies.

Results and discussion

This study presents an overview of available indicators and LCIAs for bioeconomy sustainability assessments as well as their link to the SDGs. We provide a practical framework for HILCSA of regional bioeconomy, which includes an indicator set for regional (product and territorial) bioeconomy assessment, applicable with current software and databases, LCIA methods and methods of normalization, weighting, and aggregation. The implementation of HILCSA in openLCA allows an integrative LCSA by conducting all steps in a single framework with harmonized, aggregated, and coherent results. HILCSA is capable of a sustainability assessment in terms of planetary boundaries, provisioning system and societal needs, as well as communication of results to different stakeholders.

Conclusions

Our framework is capable of compensating some deficits of S-LCA, E-LCA, and economic assessments by integration, and shows main advantages compared to additive LCSA. HILCSA is capable of addressing 15 out of 17 SDGs. It addresses open questions and significant problems of LCSAs in terms of goal and scope, LCI, LCIA, and interpretation. Furthermore, HILCSA is the first of its kind actually applicable in an existing software environment. Regional bioeconomy sustainability assessment is bridging scales of global and regional effects and can inform stakeholders comprehensively on various impacts, hotspots, trade-offs, and synergies of regional bioeconomy. However, significant research needs in LCIAs, software, and indicator development remain.

     

Prioritizing regionalization to enhance interpretation in consequential life cycle assessment: application to alternative transportation scenarios using partial equilibrium economic modeling

Purpose

Consequential life cycle assessment (C-LCA) aims to assess the environmental consequences of a decision. It differs from traditional LCA because its inventory includes all the processes affected by the decision which are identified by accounting for causal links (physical, economic, etc.). However, C-LCA results could be quite uncertain which makes the interpretation phase harder. Therefore, strategies to assess and reduce uncertainty in C-LCA are needed. Part of uncertainty in C-LCA is due to spatial variability that can be reduced using regionalization. However, regionalization can be complex and time-consuming if straightforwardly applied to an entire LCA model.

Methods

The main purpose of this article is to prioritize regionalization efforts to enhance interpretation in C-LCA by assessing the spatial uncertainty of a case study building on a partial equilibrium economic model. Three specific objectives are derived: (1) perform a C-LCA case study of alternative transportation scenarios to investigate the benefits of implementing a public policy for energy transition in France by 2050 with an uncertainty analysis to explore the strength of our conclusions, (2) perform global sensitivity analyses to identify and quantify the main sources of spatial uncertainty between foreground inventory model from partial equilibrium economic modeling, background inventory model and characterization factors, (3) propose a strategy to reduce the spatial uncertainty for our C-LCA case study by prioritizing regionalization.

Results and discussion

Results show that the implementation of alternative transport scenarios in compliance with public policy for the energy transition in France is beneficial for some impact categories (ICs) (global warming, marine acidification, marine eutrophication, terrestrial acidification, thermally polluted water, photochemical oxidant formation, and particulate matter formation), with a confidence level of 95%. For other ICs, uncertainty reduction is required to determine conclusions with a similar level of confidence. Input variables with spatial variability from the partial equilibrium economic model are significant contributors to the C-LCA spatial uncertainty and should be prioritized for spatial uncertainty reduction. In addition, characterization factors are significant contributors to the spatial uncertainty results for all regionalized ICs (except land occupation IC).

Conclusions

Ways to reduce the spatial uncertainty from economic modeling should be explored. Uncertainty reduction to enhance the interpretation phase and the decision-making should be prioritized depending on the goal and scope of the LCA study. In addition, using regionalized CFs in C-LCA seems to be relevant, and C-LCA calculation tools should be adapted accordingly.