Showing papers in "International Journal of Life Cycle Assessment in 2020"

Comparing sources and analysis of uncertainty in consequential and attributional life cycle assessment: review of current practice and recommendations

Abstract: Life cycle assessment (LCA) is intended as a quantitative decision support tool. However, the large amount of uncertainty characteristic of LCA studies reduces confidence in results. To date, little research has been reported regarding the comparative sources of uncertainty (and their relative importance) and how, or how commonly, they are quantified in attributional and consequential LCA. This paper answers these questions based on a review of recent LCA studies and methods papers, and advances recommendations for improved practice. All relevant LCA methods papers as well as case studies (amounting to 2687 journal articles) published from 2014 to 2018 in the top seven journals publishing LCA studies were reviewed. Common sources and methods for analysis of uncertainty in both attributional and consequential LCA were described, and their frequency of application evaluated. Observed practices were compared to best practice recommendations from methods papers, and additional recommendations were advanced. Less than 20% of LCA studies published in the past five years reported any kind of uncertainty analysis. There are many different sources of uncertainty in LCA, which can be classified as parameter, scenario or model uncertainty. Parameter uncertainty is most often reported, although the other types are considered equally important. There are also sources of uncertainty specific to each kind of LCA—in particular related to the resolution of multi-functionality problems (i.e. allocation in attributional LCA versus the definition of market-mediated substitution scenarios in consequential LCA). However, there are currently no widely applied methods to specifically account for these sources of uncertainty other than sensitivity analysis. Monte Carlo sampling was the most popular method used for propagating uncertainty results, regardless of LCA type. Data quality scores and inherent (i.e. stochastic) uncertainty data are widely available in LCI databases, and researchers should generally be able to define comparable uncertainty information for their primary data. Moreover, uncertainty propagation for parameter uncertainty is supported by LCA modelling software. There are hence no obvious barriers to quantifying parameter uncertainty in LCA studies. More standardized methods based upon context-specific data that strike the right balance between comprehensiveness and usability are, however, necessary in order to better account for both the shared and unique sources of uncertainty in attributional and consequential LCAs. More frequent and comprehensive reporting of uncertainty analysis is strongly recommended for published LCA studies. Improved practices should be encouraged and supported by peer-reviewers, editors, LCI databases and LCA software developers.

Mineral resources in life cycle impact assessment: part II – recommendations on application-dependent use of existing methods and on future method development needs

Abstract: Assessing impacts of abiotic resource use has been a topic of persistent debate among life cycle impact assessment (LCIA) method developers and a source of confusion for life cycle assessment (LCA) practitioners considering the different interpretations of the safeguard subject for mineral resources and the resulting variety of LCIA methods to choose from. Based on the review and assessment of 27 existing LCIA methods, accomplished in the first part of this paper series (Sonderegger et al. 2020), this paper provides recommendations regarding the application-dependent use of existing methods and areas for future method development. Within the “global guidance for LCIA indicators and methods” project of the Life Cycle Initiative hosted by UN Environment, 62 members of the “task force mineral resources” representing different stakeholders discussed the strengths and limitations of existing LCIA methods and developed initial conclusions. These were used by a subgroup of eight members at the Pellston Workshop® held in Valencia, Spain, to derive recommendations on the application-dependent use and future development of impact assessment methods. First, the safeguard subject for mineral resources within the area of protection (AoP) natural resources was defined. Subsequently, seven key questions regarding the consequences of mineral resource use were formulated, grouped into “inside-out” related questions (i.e., current resource use leading to changes in opportunities for future users to use resources) and “outside-in” related questions (i.e., potential restrictions of resource availability for current resource users). Existing LCIA methods were assigned to these questions, and seven methods (ADPultimate reserves, SOPURR, LIME2endpoint, CEENE, ADPeconomic reserves, ESSENZ, and GeoPolRisk) are recommended for use in current LCA studies at different levels of recommendation. All 27 identified LCIA methods were tested on an LCA case study of an electric vehicle, and yielded divergent results due to their modeling of impact mechanisms that address different questions related to mineral resource use. Besides method-specific recommendations, we recommend that all methods increase the number of minerals covered, regularly update their characterization factors, and consider the inclusion of secondary resources and anthropogenic stocks. Furthermore, the concept of dissipative resource use should be defined and integrated in future method developments. In an international consensus-finding process, the current challenges of assessing impacts of resource use in LCA have been addressed by defining the safeguard subject for mineral resources, formulating key questions related to this safeguard subject, recommending existing LCIA methods in relation to these questions, and highlighting areas for future method development.

Mineral resources in life cycle impact assessment—part I: a critical review of existing methods

Abstract: Purpose The safeguard subject of the Area of Protection "natural Resources," particularly regarding mineral resources, has long been debated. Consequently, a variety of life cycle impact assessment methods based on different concepts are available. The Life Cycle Initiative, hosted by the UN Environment, established an expert task force on "Mineral Resources" to review existing methods (this article) and provide guidance for application-dependent use of the methods and recommendations for further methodological development (Berger et al. in Int J Life Cycle Assess, 2020). Methods Starting in 2017, the task force developed a white paper, which served as its main input to a SETAC Pellston Workshop (R) in June 2018, in which a sub-group of the task force members developed recommendations for assessing impacts of mineral resource use in LCA. This article, based mainly on the white paper and pre-workshop discussions, presents a thorough review of 27 different life cycle impact assessment methods for mineral resource use in the "natural resources" area of protection. The methods are categorized according to their basic impact mechanisms, described and compared, and assessed against a comprehensive set of criteria. Results and discussion Four method categories have been identified and their underlying concepts are described based on existing literature: depletion methods, future efforts methods, thermodynamic accounting methods, and supply risk methods. While we consider depletion and future efforts methods more "traditional" life cycle impact assessment methods, thermodynamic accounting and supply risk methods are rather providing complementary information. Within each method category, differences between methods are discussed in detail, which allows for further sub-categorization and better understanding of what the methods actually assess. Conclusions We provide a thorough review of existing life cycle impact assessment methods addressing impacts of mineral resource use, covering a broad overview of basic impact mechanisms to a detailed discussion of method-specific modeling. This supports a better understanding of what the methods actually assess and highlights their strengths and limitations. Building on these insights, Berger et al. (Int J Life Cycle Assess, 2020) provide recommendations for application-dependent use of the methods, along with recommendations for further methodological development.

Comparative LCA of concrete with recycled aggregates: a circular economy mindset in Europe

Abstract: Construction and demolition waste (CD however, the production of sodium silicate and sodium hydroxide has a great environmental impact. A possible future implementation of the present study is certainly to carry out an overall assessment and to determine the most cost-effective option among the different competing alternatives through the life cycle cost analysis.

On the number of Monte Carlo runs in comparative probabilistic LCA

Abstract: The Monte Carlo technique is widely used and recommended for including uncertainties LCA. Typically, 1000 or 10,000 runs are done, but a clear argument for that number is not available, and with the growing size of LCA databases, an excessively high number of runs may be a time-consuming thing. We therefore investigate if a large number of runs are useful, or if it might be unnecessary or even harmful. We review the standard theory or probability distributions for describing stochastic variables, including the combination of different stochastic variables into a calculation. We also review the standard theory of inferential statistics for estimating a probability distribution, given a sample of values. For estimating the distribution of a function of probability distributions, two major techniques are available, analytical, applying probability theory and numerical, using Monte Carlo simulation. Because the analytical technique is often unavailable, the obvious way-out is Monte Carlo. However, we demonstrate and illustrate that it leads to overly precise conclusions on the values of estimated parameters, and to incorrect hypothesis tests. We demonstrate the effect for two simple cases: one system in a stand-alone analysis and a comparative analysis of two alternative systems. Both cases illustrate that statistical hypotheses that should not be rejected in fact are rejected in a highly convincing way, thus pointing out a fundamental flaw. Apart form the obvious recommendation to use larger samples for estimating input distributions, we suggest to restrict the number of Monte Carlo runs to a number not greater than the sample sizes used for the input parameters. As a final note, when the input parameters are not estimated using samples, but through a procedure, such as the popular pedigree approach, the Monte Carlo approach should not be used at all.

Applications of nutritional functional units in commodity-level life cycle assessment (LCA) of agri-food systems

Abstract: The nutritional quality of final products is attracting an increased level of attention within life cycle assessment (LCA) literature of agri-food systems. The majority of these studies, however, are based on comparisons at the dietary level and, therefore, are unable to offer immediate implications for farmers as to how best to produce food. This article evaluates recent literature examining the nutrition-environment nexus at the commodity level, with the aim to identify potential pathways towards sustainability analysis that can inform both consumers and producers. A systematic search of literature was carried out to produce a shortlist of studies, and strict exclusion criteria were applied to them afterwards to eliminate irrelevant material. The studies thus selected were classified into one of three tiers based on the level of complexity with regard to their functional units: (1) based on single nutrients, (2) based on composite indicators derived from multiple nutrients and (3) based on commodity-level analysis in a dietary context. Sixteen papers were identified for inclusion in the review. All of them accounted for climate change either directly or indirectly, whilst only five addressed different impact categories at the same time. Nine studies estimated environmental impacts under functional units associated with nutrient density scores, and the others utilised alternative approaches to account for nutritional value such as linear programming and end-point modelling combined with epidemiological data. A recently developed method to calculate the marginal contribution of a commodity to the overall nutritional value of a specific diet was considered to be a successful first step in bridging the aforementioned knowledge gap. The LCA community should continue the ongoing effort to link farm management decisions to diet-level environmental impacts through an enhanced focus on human nutrition across the entire value chain. Future research comparing environmental performances of multiple food groups or multiple production systems should acknowledge differences in nutritional composition and bioavailability between the final products and, ideally, the effects of these nutrients on overall dietary quality.

Temporal issues in life cycle assessment—a systematic review

Abstract: Case studies on life cycle assessments frequently admit that the precision of their outcome could be undermined due to temporal issues, though they usually refrain from offering much more detail. In addition, available overview papers and reviews on problems and challenges in LCA do not address the whole range of temporal issues. As those are major sources of inaccuracies and influence each other, it is important to get a clear picture of them, to close gaps in definitions, to systemize temporal issues, and to show their interdependencies and proposed solutions. In order to identify the state of science on those questions, we conducted a systematic literature review. We first systematized temporal issues based on ISO 14040ff and divided them into six types: time horizon, discounting, temporal resolution of the inventory, time-dependent characterization, dynamic weighting, and time-dependent normalization. Building on that, we identified suitable search terms and developed an analysis grid for the content analysis. We included only methodological papers and case studies with original findings on solutions for temporal issues. Bibliographic data, impact types, industrial fields, and methodological contributions were analyzed. Literature differentiates between different types of time horizons. There is one for the whole assessment, defined in goal and scope, one for the life cycle inventory, and one for the impact characterization. Setting a time horizon for the assessment is regarded as equivalent to the application of discounting. Both very long and very short time horizons of the assessment are not practical depending on the topic assessed in the LCA. Very short ones would offend the principle of intergenerational equality, while very long ones would marginalize short-term actions and thereby reduce incentives to act. There is consensus in the literature that temporally differentiated life cycle inventories and time-dependent, or at least time horizon dependent, characterization improve the accuracy of LCA. Generally, dynamic life cycle assessments are attractive for companies because the calculation results are not only more accurate but are often also lower than in static life cycle assessments. The main questions where we did not find consensus are the issue of the length of the time horizon of the assessment and the issue of discounting. Those are regarded as subjective and are encountered with sensitivity or scenario analysis. Further investigations should be taken for a better understanding of this issue and for concrete solutions because their influence on the results of life cycle assessments is often fundamental.

A taste of the new ReCiPe for life cycle assessment: consequences of the updated impact assessment method on food product LCAs

Abstract: Recently, an update of the Life Cycle Impact Assessment (LCIA) method ReCiPe was released: ReCiPe 2016. The aim of this study was to analyse the effect of using this update instead of the previous version: ReCiPe 2008. Do the absolute outcomes change significantly and if so, does this lead to different conclusions and result-based recommendations? Life cycle assessments (LCAs) were conducted for 152 foods for which cradle-to-plate inventories were available and that together are estimated to account for 80% of the total greenhouse gas emissions, land use and fossil resource depletion of food consumption in the Netherlands. The LCIA was performed on midpoint and endpoint level, with both ReCiPe 2008 and 2016, and using the three perspectives provided by ReCiPe. Both the uses of the global-average characterisation factors (CFs) and the Dutch-specific CFs were explored. Results showed a strong correlation between LCAs performed with ReCiPe 2008 and with 2016 on midpoint and endpoint level, with Spearman’s rank correlation between 0.85 and 0.99. Ranking of foods related to their overall environmental impact did not differ significantly between methods when using the default hierarchist perspective. Differences on endpoint level were largest when using the individualist perspective. The predicted average absolute impact of the foods studied did change significantly when using the new ReCiPe, regardless of which perspective was used: a larger impact was found for climate change, freshwater eutrophication and water consumption and a lower impact for acidification and land use. The use of Dutch CFs in ReCiPe 2016 leads to significant differences in LCA results compared with the use of the global-average CFs. When looking at the average Dutch diet, ReCiPe 2016 predicted a larger impact from greenhouse gas emissions and freshwater eutrophication, and a lower impact from acidification and land use than ReCiPe 2008. The update of ReCiPe leads to other LCIA results but to comparable conclusions on hotspots and ranking of food product consumption in the Netherlands. Looking at the changes per product due to the update, we recommend updating endpoint-level LCAs conducted with ReCiPe 2008, especially for products that emit large amounts of PM2.5 or consume large amounts of water within their life cycle. As new and updated methods reflect the scientific state of art better and therefore include less model uncertainty, we recommend to always use the most recent and up-to-date methodology in new LCAs.

Upscaling methods used in ex ante life cycle assessment of emerging technologies: a review

Abstract: The objective of this paper was to provide LCA practitioners with recommendations and a framework for upscaling emerging technologies by reviewing upscaling methods applied so far in ex ante life cycle assessment (LCA). Web of Science was searched for articles published between 1990 and 2019 (April) using different variations of the term “ex ante LCA” as keywords. Suitable studies were reviewed to understand the key characteristics and main methodological principles of upscaling methods. A total of 18 studies were selected for literature review. Review results showed that most studies reported what a hypothetical upscaled technology would look like in the future. All studies described how they estimated data; they applied different data estimation methods, using process simulation, manual calculations, molecular structure models (MSMs) and proxies. Since the review results showed that most ex ante LCA studies followed similar upscaling steps, we developed a framework for the upscaling of emerging technologies in ex ante LCA consisting of three main steps: (1) projected technology scenario definition, (2) preparation of a projected LCA flowchart, and (3) projected data estimation. Finally, a decision tree was developed based on the review results that provides recommendations for LCA practitioners regarding the upscaling procedure in ex ante LCA. Our findings can be useful for LCA practitioners aiming at upscaling in ex ante LCA. We provide an overview of upscaling methods used in ex ante LCA and introduce a framework describing the steps involved in the upscaling process and a decision tree recommending an up-scaling procedure. The results show that in theory all data estimation methods described in this paper can be applied to estimate material flows, energy flows, and elementary flows (emissions and natural resource use). Finally, since different kinds of expertise are required for upscaling in ex ante LCA, we recommend that technology experts from different fields are involved in performing ex ante LCA, e.g., technology developers, LCA practitioners, and engineers.

Fishmeal partial substitution within aquafeed formulations: life cycle assessment of four alternative protein sources

Abstract: Fed aquaculture has long been based on fishmeal (FM) as the main protein source for carnivorous species, but when its demand and price began increasing, both researchers and the industry started to search for alternative protein sources to meet the challenge of securing aquafeed. Consequently, this study has recourse to life cycle assessment (LCA) methodology to identify any critical points and improvement strategies in the current production of four partial substitutes for FM namely dried microalgae biomass from Tetraselmis suecica (DMB_TETRA) and Tisochrysis lutea (DMB_TISO); insect meal (IM) from Hermetia illucens larvae; and poultry by-product meal (PBM). System boundaries are from the cradle to the mill gate, thus including the production phase (and the related upstream activities) and the subsequent biomass processing into unpackaged dried meal. One tonne of protein content was chosen as functional unit. The inventory was based on foreground data provided by the industry and complemented by background data sourced from the Ecoinvent v 3.4 and Agribalyse® v 1.3 LCI databases. The environmental effects were assessed considering five impacts namely global warming (kg CO2 eq.), acidification (kg SO2 eq.) and eutrophication (kg PO43− eq.) estimated via the CML-IA method, plus cumulative energy use (MJ) and water use (m3 m−2 month−1). Two alternative scenarios per production chain were considered in order to increase the robustness of the results. The performance-based ranking indicated the PBM and IM scenarios as the most sustainable options. Both microalgal systems scored the worst performances in four impacts out of five, with eutrophication impact as the only exception. The nutrients provided to poultry and insects (i.e. the feed) as well as to microalgae (the carbon source and the fertilizers) were the main contributors to impacts, together with energy consumption. Despite being cultivated with identical technologies, the two microalgae showed different performances due to their different annual yields and to different consumable goods, water and energy consumptions. The results provided a ranking of these four partial FM substitutes and allowed to make useful considerations on how to improve their environmental sustainability. To this regard, the impacts of IM and DMB production could be reduced by improving nutrient efficiency and reducing energy needs. On the other hand, PBM production is already optimized and is not expected to change substantially in the future years.

Environmental impacts associated with the production, use, and end-of-life of a woollen garment.

Abstract: The textiles industry is a substantial contributor to environmental impacts through the production, processing, use, and end-of-life of garments. Wool is a high value, natural, and renewable fibre that is used to produce a wide range of garments, from active leisure wear to formal wear, and represents a small segment of the global fashion industry. Woollen garments are produced by long, global value chains extending from the production of ‘greasy’ wool on sheep farms, through processing to garment make-up, retail, consumer use, and end-of-life. To date, there have been limited life cycle assessment (LCA) studies on the environmental impacts of the full supply chain or use phase of garments, with the majority of wool LCA studies focusing on a segment of the supply chain. This study aimed to address this knowledge gap via a cradle-to-grave LCA of a woollen garment. This study investigated greenhouse gas (GHG) emissions, fossil fuel energy, and water stress associated with the production, use, and end-of-life of a lightweight woollen sweater (300-g wool), together with inventory results for freshwater consumption and land occupation. Primary datasets were used for the wool production and wool processing stages, while primary datasets relating to consumer garment use were supplemented with literature data. Impacts were calculated and reported per garment wear event. Impacts per wear were 0.17 (± 0.02) kg CO2-e GHG, 0.88 (± 0.18) MJ fossil energy, and 0.96 (± 0.42) H2O-e water stress. Fossil fuel energy was dominated by wool processing, with substantial contributions of energy also arising from retail and garment care. Greenhouse gas emissions from wool production (farming) contributed the highest proportion of impacts, followed by lower contributions from processing and garment care. Contributions to water stress varied less across the supply chain, with major contributions arising from production, processing, and garment use. Opportunities to improve the efficiency of production, processing, and garment care exist, which could also reduce resource use and impacts from wool. However, the number of garment wear events and length of garment lifetime was found to be the most influential factor in determining garment impacts. This indicated that consumers have the largest capacity to influence the sustainability of their woollen garments by maximising the active garment lifespan which will reduce overall impacts.

Abiotic resource depletion potentials (ADPs) for elements revisited—updating ultimate reserve estimates and introducing time series for production data

Abstract: The original version of this article unfortunately contained a mistake which was missed during typesetting. The caption to Fig. 5 was incorrect. The correct version is given below.

Flaws in the interpretation phase of bioenergy LCA fuel the debate and mislead policymakers

Abstract: We hypothesize that the current heated scientific debate on bioenergy sustainability is fuelled by flaws in the interpretation phase of bioenergy LCA studies rather than by the lack of studies or shared methodologies. The interpretation phase is the key step in LCA studies, which guarantees their quality and consistency and gives meaning to the work carried out by delivering results that are consistent with the defined goal and scope, which reach conclusions, and explain limitations. To test our hypothesis, we selected the 100 most cited articles found in Scopus utilizing a query to include most of the relevant works on LCA of bioenergy. The rationale underpinning the choice of the most cited articles is that these are presumably the most influential. A further screening identified off-topic articles, reviews, and methodological papers, which were discarded. We have also checked whether the articles analysed referred to the ISO standards. The study is organized as a reasoned and parametrized review in which we assess the methodological approach of the studies, rather than the results obtained. We find that overlooking some of the fundamental steps in the interpretation phase in bioenergy LCA is a rather common practice. Although most of the studies referred to the ISO standards, the identification of issues, their framing with sensitivity analyses, and the identification and reporting of limitations, which are all needed to comply with ISO14044 standards, are often neglected by practitioners. The most problematic part of the interpretation phase is the consistency check. In most cases, the assessment framework built is not apt at answering the question set in the goal. Limitations are properly identified and reported only in few studies. We conclude that in many studies either the conclusions and recommendations drawn are not robust because the inventory and the impact assessment phases are not consistent with the goal of the study, or the conclusions and recommendations go well beyond what the limitations of the study would allow. In our opinion, these flaws in the interpretation phase of influential LCA studies are among the responsible factors that continue to fuel the debate around the sustainability of bioenergy. We report a set of recommendations both for LCA practitioners and for users to guide the LCA practitioners in properly organizing and reporting their work, and to facilitate the readers in understanding and evaluating the significance and applicability of the results presented.

Extending sensitivity analysis using regression to effectively disseminate life cycle assessment results

Abstract: Bottom-up–based life cycle assessment (LCA) approaches are used to assess the greenhouse gas emissions of various products such as transportation fuels. Bottom-up spreadsheet–based models include numerous calculations and assumed values that are uncertain. Currently, most LCAs provide point estimates with a simple one-at-a-time sensitivity analysis, which provides limited insight into how the model assumptions affect the results. Additionally, the LCA models are generally presented with a limited number of scenarios to avoid overwhelming the reader; however, this limits the usefulness of the work, as each reader will be interested in different scenarios. The goal of this work is to use a global sensitivity and regression to provide as much information to the reader as possible in an easily digestible form. The Morris and Sobol global sensitivity methods are examined to determine if they can accurately identify the key inputs that have the largest effect on overall output variance. A multiparameter linear regression is then used to simplify the model into a single equation. Rstudio and Excel VBA are used to create an easy-to-use template called the Regression, Uncertainty, and Sensitivity Tool (RUST) that can be inserted into any Excel-based LCA model. This method is applied to the previously published FUNdamental ENgineering PrinciplEs-based ModeL for Estimation of GreenHouse Gases in Conventional Crude Oils and Oil Sands (FUNNEL-GHG-CCO/OS) as an example case. Both the Morris and Sobol methods can identify the key parameters, but the Morris method requires less than 1/100th as many model evaluations. Of the model’s 65 parameters, 14 key parameters were identified. The corresponding regression model was found to have an accuracy of ± 0.5 g CO2 eq/MJ 90% of the time and a maximum error of + 3 and − 1 g CO2 eq/MJ. This work found that the Morris method can be used to screen key parameters and that a stepwise multiparameter linear regression approach can be used to develop a simplified version of the model. The developed RUST Excel workbook can be used to perform the sensitivity and regression analysis of any Excel-based LCA models. The regression model can then be easily published, it does not require a large effort to make a user friendly version of the model, and it conceals confidential data if necessary. The simplified model makes it easy for policy markets to investigate how changes in critical parameters affect the LCA results without having to learn how to use the full complex model.

Life cycle assessment of electricity generation: a review of the characteristics of existing literature

Abstract: The environmental impacts of electricity generation are a critical issue towards sustainability and thus an important research topic in several countries. The life cycle assessment methodology has been widely employed to assess electricity generation. However, there are still gaps in research to be explored within this theme. Therefore, this paper aims to conduct a systematic theoretical analysis of the state of the art of the scientific research on LCA of electricity generation systems in the world. A critical review of 47 studies was conducted. The study is comprehensive in the analysis of the main aspects of the identified high impact studies as follows: authors, countries, universities, keywords, journals, number of citations, life cycle impact assessment methods, impact categories, software tools, and databases. The Methodi Ordinatio was applied to rank the studies in terms of impact factor and number of citations, pointing out high impact research. Wind and solar powers have two of the smallest impact indices in their generation in terms of global warming, compared to other sources. The ecoinvent database was the most used among the studies analyzed, providing data for potential environmental impacts. The most frequently used impact category in the assessments was climate change. The studies are not equally distributed but most of them are concentrated in European countries. In some countries, clean sources seem promising due to their capacity to generate electricity in places with high wind incidence and high capacity for sunlight capture. The conclusions of this article summarize the characteristics of existing literature and provide suggestions for future work. The results of the study can also be used to promote development actions and foment changes in energy matrices in a global context. The main studies in this area point that in the future, the main sources for electricity generation will be renewable ones, since life cycle assessment of electricity generation systems has been seeking to generate knowledge to support informed decision-making.

A life cycle environmental sustainability analysis of microbial protein production via power-to-food approaches

Abstract: Renewable energy produced from wind turbines and solar photovoltaics (PV) has rapidly increased its share in global energy markets. At the same time, interest in producing hydrocarbons via power-to-X (PtX) approaches using renewables has grown as the technology has matured. However, there exist knowledge gaps related to environmental impacts of some PtX approaches. Power-to-food (PtF) application is one of those approaches. To evaluate the environmental impacts of different PtF approaches, life cycle assessment was performed. The theoretical environmental potential of a novel concept of PtX technologies was investigated. Because PtX approaches have usually multiple technological solutions, such as the studied PtF application can have, several technological setups were chosen for the study. PtF application is seen as potentially being able to alleviate concerns about the sustainability of the global food sector, for example, as regards the land and water use impacts of food production. This study investigated four different environmental impact categories for microbial protein (MP) production via different technological setups of PtF from a cradle-to-gate perspective. The investigated impact categories include global warming potential, blue-water use, land use, and eutrophication. The research was carried out using a life cycle impact assessment method. The results for PtF processes were compared with the impacts of other MP production technologies and soybean production. The results indicate that significantly lower environmental impact can be achieved with PtF compared with the other protein production processes studied. The best-case PtF technology setups cause considerably lower land occupation, eutrophication, and blue-water consumption impacts compared with soybean production. However, the energy source used and the electricity-to-biomass efficiency of the bioreactor greatly affect the sustainability of the PtF approach. Some energy sources and technological choices result in higher environmental impacts than other MP and soybean production. When designing PtF production facilities, special attention should thus be given to the technology used. With some qualifications, PtF can be considered an option for improving global food security at minimal environmental impact. If the MP via the introduced application substitutes the most harmful practices of production other protein sources, the saved resources could be used to, for example, mitigation purposes or to improve food security elsewhere. However, there still exist challenges, such as food safety–related issues, to be solved before PtF application can be used for commercial use.

Allocation in life cycle assessment of lignin

Abstract: 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. 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 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. 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.

Identifying eco-efficient year-round crop combinations for rooftop greenhouse agriculture

Abstract: Rooftop greenhouses (RTGs) are agricultural systems that can improve the food supply chain by producing vegetables in unused urban spaces. However, to date, environmental assessments of RTGs have only focused on specific crops, without considering the impacts resulting from seasonality, combinations of crops and nonoperational time. We analyze vegetable production in an RTG over 4 years to determine the crop combinations that minimize yearly environmental impacts while diversifying food supply. The system under study consists of an integrated RTG (i-RTG) with a hydroponic system in Barcelona, in the Mediterranean region. By using life cycle assessment (LCA), we evaluate the environmental performance of 25 different crop cycles and 7 species cultivated during the period 2015–2018. Three functional units are used: 1 kg of edible fresh production, 1 unit of economic value (€) in the wholesale market and 1 kcal of nutritional value. The system boundaries consider two subsystems: infrastructure (greenhouse structure, rainwater harvesting system and auxiliary equipment) and operation (fertilizers and their emissions into water and substrate). In addition, we perform an eco-efficiency analysis, considering the carbon footprint of the crop cycles and their value at the wholesale market during their harvesting periods. Spring tomato cycles exert the lowest impacts in all categories, considering all three functional units, due to the high yields obtained. In contrast, spinach and arugula have the highest impacts. Regarding relative impact, the greenhouse structure presented a large impact, while fertilizer production had notable relative contributions in tomato cycles. Moreover, nitrogen and phosphorus emissions from fertigation are the main causes of freshwater and marine eutrophication. By combining the most eco-efficient cycles, we can see that growing two consecutive tomato cycles is the best alternative with the functional unit of yield (0.49 kg CO2 eq./kg), whereas a long spring tomato cycle combined with bean and lettuce cycles in the autumn/winter is the best scenario when using market (0.70 kg CO2 eq./€) and nutritional value (3.18·10−3 kg CO2/ kcal). This study shows that increasing the diversity of the system leads to better environmental performance of greenhouse urban agriculture if suitable crops are selected for the autumn/winter season. The functional unit involving the economic value and the eco-efficiency analysis are useful to demonstrate the capability of the growing system to produce added-value vegetables under harsher conditions while categorizing and classifying the crops to select the most suitable combinations based on economic and environmental parameters.

A tool to operationalize dynamic LCA, including time differentiation on the complete background database

Abstract: The objective is to demonstrate an operational tool for dynamic LCA, based on the model by Tiruta-Barna et al. (J Clean Prod 116:198-206, Tiruta-Barna et al. 2016). The main innovation lies in the combination of full temporalization of the background inventory and a graph search algorithm leading to full dynamic LCI, further coupled to dynamic LCIA. The following objectives were addressed: (1) development of a database with temporal parameters for all processes of ecoinvent 3.2, (2) implementation of the model and the database in integrated software, and (3) demonstration on a case study comparing a conventional internal combustion engine car to an electric one. Calculation of dynamic LCA (including temporalization of background and foreground system) implies (i) a dynamic LCI model, (ii) a temporal database including temporal characterization of ecoinvent 3.2, (iii) a graph search algorithm, and (iv) dynamic LCIA models, in this specific case for climate change. The dynamic LCI model relies on a supply chain modeling perspective, instead of an accounting one. Unit processes are operations showing a specific functioning over time. Mass and energy exchanges depend on specific supply models. Production and supply are described by temporal parameters and functions. The graph search algorithm implements the dynamic LCI model, using the temporal database, to derive the life cycle environmental interventions scaled to the functional unit and distributed over time. The interventions are further combined with the dynamic LCIA models to obtain the temporally differentiated LCA results. A web-based tool for dynamic LCA calculations (DyPLCA) implementing the dynamic LCI model and temporal database was developed. The tool is operational and available for testing (http://dyplca.univ-lehavre.fr/). The case study showed that temporal characterization of background LCI can change significantly the LCA results. It is fair to say that temporally differentiated LCI in the background offers little interest for activities with high downstream emissions. It can provide insightful results when applied to life cycle systems where significant environmental interventions occur upstream. Those systems concern, for example, renewable electricity generation, for which most emissions are embodied in an infrastructure upstream. It is also observed that a higher degree of infrastructure contribution leads to higher spreading of impacts over time. Finally, a potential impact of the time window choice and discounting was observed in the case study, for comparison and decision-making. Time differentiation as a whole may thus influence the conclusions of a study. The feasibility of dynamic LCA, including full temporalization of background system, was demonstrated through the development of a web-based tool and temporal database. It was showed that considering temporal differentiation across the complete life cycle, especially in the background system, can significantly change the LCA results. This is particularly relevant for product systems showing significant environmental interventions and material exchanges over long time periods upstream to the functional unit. A number of inherent limitations were discussed and shall be considered as opportunities for further research. This requires a collegial effort, involving industrial experts from different sectors.

Food loss and waste metrics: a proposed nutritional cost footprint linking linear programming and life cycle assessment

Abstract: The authors are grateful for the funding of the Spanish Ministry of Economy and Competitiveness through the Ceres-Procom: Food production and consumption strategies for climate change mitigation (CTM2016-76176-C2-1-R) (AEI/FEDER, UE).

Competitive use of sugarcane for food, fuel, and biochemical through the environmental and economic factors

Abstract: Bioethanol demands for transport face uncertainty; additionally, the emergence of electric vehicles is raising concerns among the ethanol producers towards the future demand and viability of the industry. Thus, there is a need to look for new pathways of sugar and ethanol utilization. However, the environmental and economic implications of the existing and proposed systems must be assessed to ensure sustainability. The study aims to evaluate and compare the environmental and economic performances of sugarcane for three new sugar-electricity-polylactic acid (PLA) systems with the existing sugar-electricity-ethanol system. The environmental hotspots of the existing and proposed sugarcane biorefinery systems are investigated and potential measures for enhancing environmental sustainability of the new systems identified. Life cycle assessment (LCA) is used for evaluating the environmental sustainability assessment of the sugarcane biorefinery and the eco-efficiency indicator, combining both the economic and environmental performances. The ReCiPe method with the hierarchist perspective at midpoint and the endpoint levels is used for quantifying the environmental impact scores. The reference unit is a tonne of cane processed at the biorefinery. The eco-efficiency is calculated based on the ReCiPe endpoint single score (“Pt”) and the values in “US$” of products from the different biorefinery systems. The results reveal that the PLA pathways to substitute ethanol and sugar production (PLA scenarios 1–3) can generate product values of about 83–220 US$/t cane processed leading to increased eco-efficiency values for all three PLA scenarios as compared to the existing sugar-electricity-ethanol system. The highest eco-efficiency (22 US$/Pt) is obtained for the pathways of PLA (scenario 3) and sugar-PLA (scenario 2). However, the LCA results show increased environmental impacts for all three PLA biorefinery scenarios. This implies that the new PLA pathways do not lead to “strong” eco-efficiency improvement, i.e., the improvement is not in both environmental and economic dimensions. Recommendations are provided to improve the environmental performances of both the existing and the new PLA biorefinery systems. The sugarcane-based PLA biorefinery could be an option for the case that the existing sugar-electricity-ethanol faces an uncertainty on ethanol demand. Nevertheless, there is a trade-off between the increased environmental impacts and the higher price. Strong eco-efficiency improvement must be encouraged to the sugarcane-based PLA biorefinery systems. Using high-pressure boilers at the mills and changing cultivation practices to avoid the cane trash burning are recommended for the better decoupling of the environmental and economic performance of the sugarcane biorefinery systems.

Life cycle impact assessment of microplastics as one component of marine plastic debris

Abstract: Plastic pollution in marine environments is a severe problem in the world due to misuse and mismanagement of the materials. Microplastics are a specific form of pollutants in this context and its handling is very difficult due to its very small size of particulates. Currently, the impacts of marine plastic debris are not considered. However, this type of particulates can be assessed like other emissions with the systematic and quantifiable approach in life cycle assessment (LCA). It was our goal to find and test first methodological approaches for including impacts of marine litter of microplastics to LCA. The Medellin Declaration on Marine Litter in Life Cycle Assessment and Management raised this issue in 2017 and called for LCA to address the challenges of marine litter. The present research paper focuses on how to integrate plastic debris impacts with focus on microplastics into LCA and gives a suggestion for an assessment approach. Based on a literature review, we considered various impacts to the marine environment of microplastics linked with their kinetics of the fragmentation and degradation. Subsequently, we developed a characterization LCA model for microplastics in the marine environment. We addressed therein the fate of microplastics and their specific eco-toxic effects to different organisms. We compared the impacts of different types of polymers as well and showed how these can be integrated in an assessment using the new characterization model. The assessment of marine litter impacts in LCA was strongly dependent on the number of microplastic particles produced from the original litter over time. These impacts were derived from measurements of the number of microparticles, their densities in the marine environment and their impacts to different organisms. The new characterization model includes the relationship between fragmentation and degradation and can be used for impact assessments within LCA. The question where we did not find a finally satisfying solution is the issue of the length of the time horizon of the assessment or the discounting. Those are regarded as subjective and are encountered with sensitivity or scenario analysis. Results from different time horizons can be aggregated to one figure or can be compared separately. Further investigations should be taken for a better understanding of this issue and for concrete solutions because their influence on the results of life cycle assessments is often fundamental.

Different paths in social life cycle impact assessment (S-LCIA)—a classification of type II impact pathway approaches

Abstract: In social life cycle assessment (S-LCA), we can distinguish two main types of impact assessment (LCIA): type I can be seen as a reporting approach with the use of performance reference points and type II aims at including cause-effect chains or impact pathways in the analysis. Given the heterogeneity of those type II approaches, this review provides a classification of existing type II approaches. We reviewed a total of 28 articles against the background of their main purpose, the method used, the issues covered and the origin of data (observation/characterization/ measurement). We checked the articles against (i) the reflection of an impact pathway, (ii) the availability of so-called inventory and impact indicators, and (iii) the presence of characterization models or factors translating correlations or causality. The analysis reveals three main paths to include impact pathways in S-LCA, which differ in authors’ intentions: (1) some studies identify and propose variables composing impact pathways, or frameworks gathering several pathways; (2) other studies investigate or test known pathways empirically, and until now seek mainly to link income data with health impacts at a macro scale, and (3) a last batch applies known and already quantified characterization models or factors from other research works in case studies. Until now, these case studies focus mainly on income-related social effects or on health impacts. Further, each path is further characterized and classified under nine approaches. Our findings highlight not only the heterogeneous nature of approaches, but also their common denominator which is to not consider phenomena or impacts in isolation but to consider them in relation to their sources or further impacts. It should be noted that type II studies are not only limited to quantitative approaches and variables, but can also use more qualitative variables and methods. The presented classification may be used as a guidance tool for authors to make their methodological choices. Also, our findings indicate the opportunity of extending future type II S-LCA research to variables tackled in type I studies (e.g., safe and fair employment and working conditions), beyond pathways including incomes and health impacts. This can be done by using theories from social sciences for the identification of impact pathways. Those could then further be investigated through statistical approaches or in the framework of S-LCA case studies, with specific data and potentially more qualitative methods to analyze causality or social mechanisms.

Communication through ecolabels: how discrepancies between the EU PEF and EPD schemes could affect outcome consistency

Abstract: Despite in Europe companies and policy makers perceive both the European Commission’s Product Environmental Footprint (PEF) and Type III environmental declarations as applicable tools supporting external communication or public procurement, at scientific level there is still no prompt and comprehensive comparison between the PEF Guide and the EPD requirements. Therefore, this paper aims to compare the relevant PEF Guide requirements with the key rules defined by the International EPD® System (IES)—one of the main widely accepted EPD schemes —identifying the critical discrepancies which potentially reduces the consistency of the outcomes. Coherently with the approach of the PEF Guide, the comparison was based on the analysis of the following criteria: scope, LCA application, reporting, review. Further, after a qualitative pre-assessment, the average results of the EPDs published in IES framework were evaluated in respect to the available benchmarks for the products belonging to the same categories for which the Product Environmental Footprint Category Rules (PEFCRs) were finalised. An overview of some key selected requirements contained in the PEF Guide was compared with the requirements/specifications contained in the IES GPI. Despite having a comparable scope and being based on a life cycle approach, the methods are not aligned in several key requirements, such as cut-off rules, modelling approach, allocation rules, and impact categories. The results of the comparison between the benchmarks defined in the PEFCRs and the average impacts in the EPDs show a general low comparability and, anyway, limited to the climate change impact category. This paper was aimed to compare the relevant PEF Guide requirements with the key rules defined by the IES. Several critical discrepancies have been identified concerning key requirements affecting the results. The main outcome is that PEF and GPI results cannot be considered comparable and the EU PEF and EPDs cannot be alternatively used as tools supporting Green Public Procurement (GPP) tender requirements. In conclusion, the development of ecolabels can be stimulated via several initiatives such as improving the access to good quality LCA data and strengthening the link between public procurement and environmental labels, but a lot of work is still to be done to reach the harmonisation of rules and the comparability of the results. At present, a statement of non-comparability could be added on ecolabels based on different specific rules.

Using Social Life Cycle Assessment to analyze the contribution of products to the Sustainable Development Goals: a case study in the textile sector

Abstract: Evaluation and monitoring systems are perceived as an effective tool to understand and improve the contribution of business activities to the accomplishment of the Sustainable Development Goals (SDGs). However, there is currently a lack of guidance and support on assessing the influence that the life cycle of products and services has on the SDGs. This article presents a case study where Social Life Cycle Assessment (S-LCA) is applied to understand the social performance of a textile product and its potential contribution to the SDGs. In this study, the link between the S-LCA methodology and the SDG framework was made at the indicator level, through a new classification of S-LCA indicators. This classification was aimed at indicating the positive or negative contribution of products or services into the SDGs. The method was tested with the case study of a man’s shirt whose supply chain takes place across five countries, from the cotton farming in China to the retailing in The Netherlands. The social performance of the shirt’s life cycle was analyzed through a social hotspot assessment (using PSILCA database) and a site-specific assessment following the UNEP/SETAC S-LCA guidelines. Primary data was collected for 6 different suppliers regarding 51 social indicators and four stakeholder categories (workers, local communities, value chain actors, and society). The social hotspot assessment indicated high social risks on indicators related to the following SDGs: health and well-being, affordable and clean energy, decent work, and responsible production and consumption. These risks were mainly located in Bangladesh (shirt manufacturing) and Malaysia (fabric manufacturing). The site-specific assessment indicated different results than the social risk assessment, showing worse social performance in the spinning stage (located in China). Negative scores were obtained for every supplier in at least four indicators, including working hours, safe and healthy living conditions, and access to immaterial resources. The results indicated negative social performance of the supply chain in most of the SDGs and identified points of improvement for the final retailer. The linkage of the S-LCA framework with the SDGs presented methodological challenges, mainly related to the different scope of the SDG indicators and the S-LCA indicators.

Representing crop rotations in life cycle assessment: a review of legume LCA studies

Abstract: There is an imperative to accurately assess the environmental sustainability of crop system interventions in the context of food security and climate change. Previous studies have indicated that the incorporation of legumes into cereal rotations could reduce overall environmental burdens from cropping systems. However, most life cycle assessment (LCA) studies focus on individual crops and miss environmental consequences of inter-annual crop sequence and nutrient cycling effects. This review investigates state-of-the-art representation of inter-crop rotation effects within legume LCA studies. A literature review was undertaken, starting with a search for all peer-reviewed articles with combinations of ‘LCA’, ‘legumes’ and ‘rotations’ or synonyms thereof. In total, 3180 articles were obtained. Articles were screened for compliance with all of the following requirements: (i) reporting results based on LCA or life cycle inventory methodology; (ii) inclusion of (a) legume(s); (iii) the legume(s) is/are analysed within the context of a wider cropping system (i.e. rotation or intercropping). Seventy articles satisfying these requirements were analysed. We identified three broad approaches to legume LCA. Most studies involved simple attributional LCA disregarding important interactions across years and crops in rotations. N-fertilizer reduction through legume residue N carryover is either disregarded or the benefit is attributed to the following crop in such studies, whilst N leaching burdens from residues are usually attributed to the legume crop. Some studies applied robust allocation approaches and/or complex functional units to enable analysis of entire rotation sequences, accounting for nutrient cycling and break crop effects. Finally, a few studies applied consequential LCA to identify downstream substitution effects, though these studies did not simultaneously account for agronomic effects of rotational sequence changes. We recommend that LCA studies for legume cropping systems should (i) evaluate entire rotations; (ii) represent nitrogen and ideally carbon cycling; (iii) for attributional studies, define at least two functional units, where one should encompass the multifunctional outputs of an entire rotation and the other should enable product footprints to be calculated; (iv) for CLCA studies, account for both agronomic changes in rotations and markets effects; (v) include impact categories that reflect hotspots for agricultural production.

The environmental attributes of wood fiber composites with bio-based or petroleum-based plastics.

Abstract: While bio-based composites (bio-based plastics reinforced with natural fibers) have been discussed as potential sustainable alternatives to petroleum-based plastic composites, there are few quantitative environmental impact assessments of these materials. This work presents comparisons of petroleum-based and bio-based plastics as well as their composites to (1) assess environmental impacts from plastics and composite production and (2) determine which environmental impacts can be mitigated through production of bio-based composites, based on current manufacturing methods. Environmental impact assessments were performed to determine the burdens associated with cradle-to-gate production of bio-based and petroleum-based plastics and their composites with wood flour (i.e., sawdust) filler. The scope of this work incorporated emissions from thermoplastic and wood flour production as well as pelletization, molding, and transportation processes. Environmental impacts were assessed for several impact categories using the US Environmental Protection Agency’s TRACI method. Using impacts quantified, as well as material property data from 36 sources in the literature, comparisons were drawn between composite types. Multiple functional units were used including a constant mass of material produced and two comparison methods normalizing environmental impacts by material properties. Uncertainty assessments were performed to determine environmental impact distributions for each plastic and wood fiber composite type. The production of bio-based plastics and their composites led to lower environmental impacts than petroleum-based plastics and composites in several impact categories: global warming potential, fossil fuel depletion, and certain human health impacts. However, the production of bio-based plastics and their composites also resulted in some higher environmental impacts, such as eutrophication. Bio-based composites are capable of possessing similar or improved mechanical properties to their petroleum-based counterparts. As such, normalized environmental impacts to material properties indicated that bio-based composites could lead to desirable combined mechanical and environmental attributes for certain applications. Considering the differences between environmental impact categories and uncertainties in environmental impact assessments, selection of constituents cannot be based solely on material feedstock to mitigate environmental impacts in wood fiber composites. Findings indicate that both environmental impact assessments and mechanical properties should be considered concurrently to effectively distinguish the benefits of selecting petroleum-based or bio-based plastics. This work shows that depending on the intended application, the selection of a bio-based feedstock could either be beneficial for mitigating certain environmental impacts, have little effect on impacts, or increase environmental impacts. These findings reveal the importance of considering property alteration and multiple effects of utilizing these resources.

In pursuit of environmentally friendly straws: a comparative life cycle assessment of five straw material options in South Africa

Abstract: The increasing global concern surrounding plastic pollution has resulted in a spotlight being placed on major contributors. Straws have been identified as a top contributor in this regard leading to a global outcry against plastic straws. This has resulted in the increasing popularity of plastic straw material alternatives. This study compares the environmental impacts associated with five straw material options available in South Africa. The straw materials compared include disposable options (polypropylene, paper and polylactide) and reusable straws (glass and steel). Plastic straws were the only option which are locally produced from local materials, whereas glass and steel straws are manufactured from imported materials and paper and polylactide straws are imported. The functional unit was based on an annual straw consumption per capita, which equates to 36 disposable straws and 1 reusable straw. The impact assessment was conducted using the Recipe Midpoint (H) method, which took into consideration 18 impact categories. The potential marine pollution impacts were explored based on the leakage propensity of the material option coupled with its degradability. The paper straw was found to have lower climate change emissions than the plastic one, which was mainly caused by the performance of the material. In South Africa, coal is used as a primary feedstock for polypropylene production making it more carbon-intensive in comparison with polypropylene produced in Europe and the USA which is primarily from crude oil and/or natural gas feedstocks. Glass and steel straws would require 23–39 and 37–63 uses respectively to break even with climate change emissions associated with disposable options. Overall, material production was the major contributor to straw emissions. The relative contribution of transportation, including import, was more dependent on the transportation mode compared with distance. For reusable straws, the washing water temperature was found to notably influence emissions. At end-of-life, reusable straws were considered unlikely to enter the marine environments. Disposable straws were found to have a leakage rate of 38%, with paper being the only marine degradable material. Overall, paper straws had the least impacts in the majority of impact categories in comparison with other disposable options and glass was more favourable to steel. In terms of marine pollution, reusable straws were deemed to pose the least risk due to their unlikelihood to be polluted. Paper was associated with the least potential impacts of the disposal options, due to its degradability.

Nutrition in the life cycle assessment of foods—function or impact?

Abstract: This work provides an unambiguous conceptual framework for inclusion of nutrition in Life Cycle Assessments (LCAs) of food that enables the distinction between two different roles of nutrition, namely serving as the basis of food comparisons via the functional unit and as an impact pathway that links food ingestion with human health effects. We compare how nutritional aspects have been considered in the functional unit of published LCAs of food with the procedural requirements for ensuring comparability of the functional units. We consider the relevance of nutrient profiling models for assessing food- and diet-related health damages and benefits in the context of LCAs of food. We finally recommend a method that will enable a systematic, comparative, and holistic assessment of the marginal health effect of food products on human health. Satiety is proposed as a central attribute for comparisons of food products, while weighted measures of nutrient content are suggested to be largely misplaced as part of the functional unit. In contrast, nutritional measures have a large role to play in assessing the human health impacts of the marginal ingestion of specific food products. Such measures should enable a direct quantification of human health effect and benefits and should take advantage of robust epidemiological evidence. Nutritional measures enter into both the functional unit in the form of satiety measures and into the calculation of impacts in the form of the marginal influence of the specific food item on the human health impact of the overall diet. To enhance the differentiation of health impacts at the level of individual food items, it is recommended to combine the nutrient balance indicator with the DALY Nutritional Index (DANI) in each specific dietary context.

Digital transformation—life cycle assessment of digital services, multifunctional devices and cloud computing

Abstract: The substitution of material-based services with digital services—for example films or music—alters the environmental impact of our everyday activities and shifts visible material use to less visible digital services. A holistic life cycle assessment (LCA) of digital transformation requires the assessment of information and communication technology (ICT) with its wide range of multifunctional devices as well as substitution and summation effects caused by new services enabled by modern ICT. The 73rd Discussion Forum on Life Cycle Assessment (DF LCA) was held on 21 November 2019 to discuss the environmental implications of digital transformation in view of the effective as well as the potential environmental impacts. While currently being a small but already relevant contributor to the overall greenhouse gas emissions, the relevance of the ICT sector is predicted to grow rapidly within the next 5 to 10 years (Belkhir & Elmeligi, 2018). This 1-day forum offered the possibility to discuss current as well as potential future implications of devices as well as digital services on the environment.