Life Cycle Assessment Practitioners Research Articles

Elementary flow mapping across life cycle inventory data systems: A case study for data interoperability under the Global Life Cycle Assessment Data Access (GLAD) initiative

PurposeLimited availability of life cycle assessment (LCA) data poses a significant challenge to its mainstream adoption, rendering it a central issue within the LCA community. The Global LCA Data Access (GLAD) network aims to increase the accessibility and interoperability of LCA data and offers benefits for different use cases. GLAD is an intergovernmental collaboration involving different stakeholders organized into working groups. The GLAD Nomenclature Working Group (NWG) developed a procedure and a set of criteria to map elementary flows among major nomenclature systems and reviewed bidirectional mappings. This paper provides an overview of the methodological approach followed by the NWG to achieve the resulting mapping files.MethodsThe mapping procedure involves several steps of flow and compartment matches and bilateral review. The procedure is supported by an ad hoc software tool called the “GLAD Mapper Tool” developed with the NWG and which is made available for free by the European Commission. The input files for the procedure are the properly formatted source and target flow lists and a file containing the mapping criteria. The four nomenclature systems mapped are those used in ecoinvent, Environmental Footprint, IDEA, and the U.S. Federal LCA Commons. The procedure included representatives from each of these nomenclature systems to ensure a multilateral agreement on the approach to verifying and assessing the quality of the results. The iterative mapping process included different stages of bidirectional reviews to achieve a balance between mapping coverage (i.e., percentage of source flows covered by the target list) and accuracy.Results and discussionThe mapping procedure proved to be an efficient approach for LCA practitioners in mappings between different nomenclature systems. After a relatively low number of iterations, mapping coverages higher than 90% were achieved, which is driven by the availability of unique substances (flow names) and the granularity of environmental compartments. Overall, none of the four flow lists achieved full coverage and the use of approximated matches (proxy matches) for environmental compartments and/or substances was necessary when a perfect matches between flows were not possible.ConclusionsThe NWG’s mapping activities may serve as a starting point towards defining a central hub for mapping impact assessment methods and datasets, improving data accessibility and interoperability for the LCA community as a step towards defining a unified nomenclature system. The GLAD mapping approach is open and transparent. The approach fosters traceability in the mapping process and offers the potential for greater interoperability across the LCA community, underlining the commitment to openness and collaboration.

Compiling life cycle inventories for wastewater-derived products

With the paradigm shift in wastewater management from pollutant removal to resource recovery, more wastewater-derived products are emerging from different recovery pathways. It is becoming increasingly important to understand the potential environmental impacts of these products through life cycle assessment (LCA). This study aims to compile life cycle inventories of wastewater-derived products from the perspective of the product end users (e.g., agricultural sector, packaging industry), and to explore the challenges of their compilation. Using inventories from wastewater resource recovery LCA literature, we compiled an attributional inventory (88 sets) and a consequential inventory (33 sets) of three categories of wastewater-derived products – phosphorus compounds, nitrogen compounds, and biopolymers. The two inventories differ by the choices of system boundary, how foreground systems are being modelled, and how co-products are being handled. We found that while there is a large body of literature related to wastewater resource recovery LCA, very few studies (29 out of 174 for the three categories of products) are suitable for end users to successfully compile inventories of derived products. The inventories were assessed by the technology readiness level assessment, the data quality assessment, and the cumulative energy demand indicator. The inventories can be used directly by end users or served as “screening” inventories for end users to prioritize data collection effort. The identified challenges of inventory compilation include diverse recovery settings, the absence of baseline scenarios, the multifunctional nature of wastewater treatment plants, the lack of inventory transparency and completeness, and low technology readiness level for some recovery pathways. While established or emerging approaches exist to address most of these challenges for end users, wastewater resource recovery LCA practitioners can enhance their assessments to be more end-user-oriented. This can be achieved by including baseline non-recovery scenarios, disclosing detailed life cycle inventory by system components, and assessing a wide variety of operating scenarios. Addressing some of these compilation challenges would enhance the comprehensiveness and quality of wastewater-derived product inventories.

Life Cycle Assessment as a Decision Tool in Material Development—Experiences from a Multi-year Carbon Fibre Composite Development Project

This paper describes what type of advice life cycle assessment can provide in different parts of a material development project. Based on experiences from a multi-year research project aiming to decrease the environmental impacts of carbon fibre composites, we aim to show and discuss what type of input we could provide the material developers at different times. The goal is to guide life cycle assessment practitioners and material developers on what role life cycle assessment can play in various project parts. Cradle-to-gate data collected at different points in time throughout the project are compiled and recalculated to the same functional unit. Assessment results from all stages clearly show that even if the carbon fibres constitute a minor share of the composite, they are the environmental hotspot with considerable potential for improvements. Depending on the timing of the project, advice ranges from being careful with the source of nitrogen in the production process to using microwave heating in carbon fibre production. We recommend material developers to include life cycle assessment as early as possible in the project. We also recommend life cycle assessment practitioners continuously work with material developers in updating the models and inventory. Additionally, we recommend that life cycle assessment practitioners add more details to the assessment and expand the study’s foreground system as the project progresses. This could be done in combination with assessing the technology readiness level of the routes. By doing so, the life cycle assessment practitioner can provide material developers insight into potential routes worth developing. It also identifies the lowest-hanging fruits for reducing the materials’ environmental impact.Graphical

Prospective life cycle assessment of sodium‐ion batteries made from abundant elements

AbstractBatteries are enablers for reducing fossil‐fuel dependency and climate‐change impacts. In this study, a prospective life cycle assessment (LCA) of large‐scale production of two different sodium‐ion battery (SIB) cells is performed with a cradle‐to‐gate system boundary. The SIB cells modeled have Prussian white cathodes and hard carbon anodes based only on abundant elements and thus constitute potentially preferable options to current lithium‐ion battery (LIB) cells from a mineral resource scarcity point of view. The functional unit was 1 kWh theoretical electricity storage capacity, and the specific energy density of the cells was 160 Wh/kg. Data for the cathode active material come from a large‐scale facility under construction and data for the SIB cell production is based on a large‐scale LIB cell gigafactory. For other SIB cell materials, prospective inventory data was obtained from a generic eight‐step procedure developed, which can be used by other LCA practitioners. The results show that both SIB cells indeed have considerably lower mineral resource scarcity impacts than nickel‐manganese‐cobalt (NMC)‐type LIB cells in a cradle‐to‐gate perspective, while their global warming impacts are on par. Main recommendations to SIB manufacturers are to source fossil‐free electricity for cell production and use hard carbon anodes based on lignin instead of phenolic resin. Additionally, since none of the assessed electrolytes had clearly lower cradle‐to‐gate impacts than any other, more research into SIB electrolyte materials with low environmental and resource impacts should be prioritized. An improvement of the SIB cell production model would be to obtain large‐scale production data specific to SIB cells.

Circular life cycle sustainability assessment: An integrated framework

AbstractRobust monitoring and assessment methods are required to assess circular economy (CE) concepts in terms of their degree of circularity and their contribution to sustainability. This research aimed to develop an integrated framework for the CE context—considering both the technical circularity and the complexity of the three dimensions of sustainability (environment, economy, and social). Two existing methods were identified as an appropriate foundation: CE indicators and life cycle sustainability assessment (LCSA), combining life cycle assessment (LCA), life cycle costing (LCC), and social life cycle assessment (S‐LCA). The developed circular life cycle sustainability assessment (C‐LCSA) framework added circularity assessment (CA) as an additional dimension to LCSA (C‐LCSA = LCA + LCC + S‐LCA + CA). The abundance of CE indicators required a systematic selection process to identify the most appropriate indicators for the framework which was built on criteria levels, performance, loops, unit, dimension, and transversality. The material circularity indicator, product circularity indicator, and longevity indicator were identified as most suited for C‐LCSA. Being developed for a single life cycle, the traditional life cycle approaches needed refinements for application to CE concepts, derived from discussions and proposed adaptions presented in the academic literature. The cut‐off approach was identified as the most suitable end‐of‐life allocation method for C‐LCSA, being in line with the technical system boundaries. C‐LCSA can be used by LCA practitioners to identify trade‐offs between an improved circularity and resulting impacts on the environmental, economic, and social pillars to provide a basis for decision making in industrial ecology.

LCA models in building industry practice - how do practitioners’ assumptions affect LCA results?

This study exemplifies uncertainties in Life Cycle Assessments (LCA) by investigating the results of nine building LCAs made by nine LCA practitioners. The study compares material quantities and Global Warming Potential (GWP) results of the nine LCAs before and after a review process. From the building LCAs before review, we identify several errors that significantly influence material quantities and GWP results. After correcting the errors, we still see notable differences in the material quantities and LCA results from the nine LCAs. The study proves a need for conducting thorough reviews to eliminate the most prominent errors in building LCAs and a need for uncertainty assessment as a standard practice.

Problematic consequences of the inclusion of capital goods inventory data in Environmental Product Declarations

PurposeA recent update to the Product Category Rules (PCRs) for Construction Products (of the International EPD System) has triggered a methodological issue for owners and users of Environmental Product Declarations (EPDs). The updated PCR has led to capital goods data being implicitly included in the Life Cycle Inventory (LCI) of EPDs. This paper critically examines the role of capital goods in EPDs and establishes major shortcomings in the current methodology, LCI datasets and interpretation.MethodsTo evaluate the role of capital goods in EPDs, this paper provides a discourse on the fundamentals of Life Cycle Assessment (LCA) methodology, scope, available LCI data and the impact of capital goods on EPD outcomes. Using the ecoinvent database, we analyse the impact of the inclusion and exclusion of capital goods in selected 38 construction products based on the EN 15804+A2 (2019) Standard. Finally, we estimate the relative contribution of capital goods to a suite of Life Cycle Impact Assessment (LCIA) indicators based on the archetypes of capital goods available in ecoinvent and apply Monte Carlo simulation to establish the range of uncertainties in the capital goods data for the selected construction products.Results and discussionOur research confirms that when capital goods are included based on currently available background LCI data, they mostly have a low effect (<10% increase) on climate change, but they can have an enormous effect (>100% increase) on abiotic depletion (minerals and metals), land use and/or human toxicity indicators. Interestingly, when looking further into the ecoinvent capital goods LCI datasets, it becomes clear that there are inaccuracies, inconsistencies, and possibly incorrect estimates of capital goods and infrastructure data. These findings raise questions about the suitability of the underlying LCI background data and whether non-attributable capital goods should be allowed to define EPD outcomes.ConclusionThe requirement for the inclusion of capital goods leads to a major conundrum for LCA practitioners. It is suggested that capital goods be excluded until there is better refinement and improvement of the quality of LCI datasets and EPD programs provide clearer guidance on dealing with capital goods. Alternatively, EPDs could document transparently the inclusion or exclusion of capital goods, so that there is a clear separation of the effects of capital goods on LCIA indicators.

MarILCA characterization factors for microplastic impacts in life cycle assessment: Physical effects on biota from emissions to aquatic environments

Although plastics emissions pose hazards to ecosystem quality, life cycle assessment (LCA) methodologies do not yet include quantification of the potential impacts of plastic leakage. To address this gap in LCA, the MarILCA working group was founded. This work contributes to MarILCA's output by providing characterization factors for assessing the impacts of aquatic (marine and freshwater) microplastic emissions through the impact category of physical effects on biota and ultimately the ecosystem quality damage category. First, the existing exposure and effect factor (EEF) for micro- and nanoplastic emissions in aquatic compartments (Lavoie et al., 2021) is updated using additional toxicity data, delivering a generic EEF of 1067.5 PAF m3/kgin compartment. Second, fate factors (FFs) are developed for eleven different polymers (EPS, PS, PA/Nylon, PP, HDPE, LDPE, PET, PVC, PLA, PHA, TRWP), three shapes (sphere/microbead, cylinder/microfiber, microplastic film fragments) and five sizes (1, 10, 100, 1000, 5000 μm). To calculate the FFs, a detailed degradation model and a simplified sedimentation model are proposed. Polymer density and size play a major role in the fate, whereas the influence of the shape is less relevant. Ultimately, the EEF and FFs are combined to deliver midpoint and endpoint characterization factors (CFs). Uncertainty is calculated with Monte Carlo analysis. Default and archetype-based CFs are recommended to LCA practitioners in case the details of emission parameters are not fully known. CFs for 1 μm microplastic size are proposed as interim CFs for nanoplastic emissions. Finally, endpoint CFs are tested in case studies within the UNEP report “Supermarket food packaging and its alternatives: Recommendations from life cycle assessments”, assessing the relative magnitude of potential microplastic impacts compared to complete LCA results. The case studies confirm that the proposed methodology contributes to filling a gap in LCA and can assist environmental decision-making on single-use plastics and their alternatives.

Are single global warming potential impact assessments adequate for carbon footprints of agri-food systems?

The vast majority of agri-food climate-based sustainability analyses use global warming potential (GWP100) as an impact assessment, usually in isolation; however, in recent years, discussions have criticised the ‘across-the-board’ application of GWP100 in Life Cycle Assessments (LCAs), particularly of food systems which generate large amounts of methane (CH4) and considered whether reporting additional and/or alternative metrics may be more applicable to certain circumstances or research questions (e.g. Global Temperature Change Potential (GTP)). This paper reports a largescale sensitivity analysis using a pasture-based beef production system (a high producer of CH4 emissions) as an exemplar to compare various climatatic impact assessments: CO2-equivalents using GWP100 and GTP100, and ‘CO2-warming-equivalents’ using ‘GWP Star’, or GWP*. The inventory for this system was compiled using data from the UK Research and Innovation National Capability, the North Wyke Farm Platform, in Devon, SW England. LCAs can have an important bearing on: (i) policymakers’ decisions; (ii) farmer management decisions; (iii) consumers’ purchasing habits; and (iv) wider perceptions of whether certain activities can be considered ‘sustainable’ or not; it is, therefore, the responsibility of LCA practitioners and scientists to ensure that subjective decisions are tested as robustly as possible through appropriate sensitivity and uncertainty analyses. We demonstrate herein that the choice of climate impact assessment has dramatic effects on interpretation, with GWP100 and GTP100 producing substantially different results due to their different treatments of CH4 in the context of carbon dioxide (CO2) equivalents. Given its dynamic nature and previously proven strong correspondence with climate models, out of the three assessments covered, GWP* provides the most complete coverage of the temporal evolution of temperature change for different greenhouse gas emissions. We extend previous discussions on the limitations of static emission metrics and encourage LCA practitioners to consider due care and attention where additional information or dynamic approaches may prove superior, scientifically speaking, particularly in cases of decision support.

Decarbonizing the lime-based construction materials industry: A practical guide for cradle-to-gate life-cycle inventory

This paper presents an integral parametrized framework to calculate the life-cycle inventory (LCI) in lime-based construction materials manufacturing, utilized for implementing decarbonization strategies in the LCI. The calcination operation is identified as the main source of CO2 emissions, with 0.79 tCO2/t CaO being inevitable (65 % of total emissions). Kiln fuel combustion contributes up to 35 % to emissions. Decarbonization strategies are ranked as: carbon capture, carbon direct avoidance, and circular economy. Parallel Flow Regenerative Kilns result in 40 % lower energy consumption compared to Long Rotary Kilns. Substituting lignite with natural gas can reduce emissions by up to 17 %. Direct CO2 separation from calcite decomposition, coupled with thermal energy recovery, can capture 65 % of the CO2 emitted, reducing kiln energy consumption by 15 % and CO2 emissions from fuel combustion by 13 %. The high purity of captured CO2 offers potential for future use as a valuable by-product. Supplementary raw materials in lime-based binder production have limited effects on CO2 emissions due to unavoidable emissions from calcite decomposition. The proposed process-oriented parametric methodology empowers Life Cycle Assessment practitioners, reducing reliance on generic databases for rigorous and transparent inventory calculations.

Data management in life cycle assessment: a case study of wastewater treatment.

To assess the environmental impact of wastewater treatment, life cycle assessment (LCA) is a frequently applied instrument. However, these studies often require large amounts of data. The complexity and heterogeneity of these data result in the need for a systematic data management approach. Especially the generation of the life cycle inventory (LCI) holds the potential to be facilitated by automation. A case study in the wastewater sector was used to demonstrate the implementation of data management. A database structure was developed to store the raw data of the wastewater plants (WWTPs) and make it accessible through code. The code interacted with the database, implemented calculations, and automatically created the inventory based on the processed data. The database provides a consistent structure for the raw data and can also be used for backup purposes. Because it is machine-readable it can be accessed through the code that enables the automated generation of the LCI. As a proof of concept, a sequence of the code is provided with a user interface and can be tested online. We found that for most use cases, basic programming tools were sufficient for systematic data management, and, therefore, the approach is considered accessible for LCA practitioners.

Methodological framework for Life Cycle Assessment of sustainable aviation (SA) systems

A comprehensive framework is proposed for Life Cycle Assessment (LCA) in the field of commercial aviation (passengers and cargo), capable to ensure transparency and comparability when evaluating the overall environmental performances of four emerging aviation systems, i.e., biofuels, electrofuels, electric, and hydrogen. The projected global revenue passenger kilometer (RPK) and is suggested as the functional unit for two timeframes representing near-term (2035) and long-term (2045), and for two segments, namely domestic and international. To solve the difficulty of comparing liquid fuels and electric aviation, the framework proposes a methodology to translate projected RPK into energy requirements for each of the studied sustainable aviation systems. Generic system boundaries are defined with their key activities for all four systems, with the biofuel system being sub-divided into two categories to distinguish whether it stems from residual or land-dependent biomass. The activities are grouped in seven categories: (i) conventional (fossil-based) kerosene activity, (ii) conversion processes from feedstock supply (to fuel or energy production for aircraft operation), (iii) counterfactual uses of constrained resources and displacement effects associated to co-products management, (iv) aircraft manufacture, (v) aircraft operation, (vi) additional infrastructure needed, and (vii) end-of-life management (aircraft and batteries). Considering applying regulations, the framework also includes a methodology to handle: (i) hybridization (the use of more than one source of energy/propulsion system to power an aircraft), (ii) the mass penalty affecting the number of carried passengers in some of the systems, and (iii) impacts stemming from non-CO2 tailpipe emissions - aspects that are currently neglected in most LCA studies. The proposed framework builds upon the most recent knowledge in the field; however, some choices are dependent on upcoming scientific advances concerning e.g., tailpipe emissions at high altitude and their environmental impacts, new aircraft configuration, etc., and are subject to significant uncertainties. Overall, this framework provides a guideline for LCA practitioners addressing new energy sources for future aviation.

Use of life cycle assessment to evaluate circular economy business models in the case of Li-ion battery remanufacturing

PurposeThe purpose of this study is to advance and illustrate how life cycle assessment (LCA) can assess circular economy business models for lithium-ion batteries to verify potential environmental benefits compared to linear business models. Scenarios for battery repurpose are assessed to support future decision-makers regarding the choice of new versus second life batteries for stationary energy storage. A procedure to determine the substitution coefficient for repurpose and reuse of batteries is proposed.MethodsTwo different circular economy business models are assessed by applying primary data from two Norwegian companies for the development of a new life cycle inventory. With this new data, the authors compare second life battery (from first life in electric vehicle) scenarios and avoided production potential by performing a complete consequential LCA. Building on earlier work, a procedure to identify the substitution coefficient (i.e., potential for avoided production) for battery life cycle assessments is proposed. Interviews during factory visits were performed to identify a technical and a market factor affecting the substitution coefficient.Results and discussionThis study illustrates how life cycle assessment methodology can detect and thus enhance the potential environmental benefits and trade-offs of circular economy business models. Results show that the CBMs which use second life batteries correspond to 16% (for global warming potential) of manufacturing a new battery. This means that a second life battery must avoid > 16% production of a new battery to become the preferred alternative. Hence, circular economy business models with second life batteries can generate net environmental benefits while the remaining battery capacity and market price are identified factors that can alter the potential environmental benefits. The findings suggest that assumptions concerning the avoided production emissions are crucial for understanding the overall impacts of battery value chains.ConclusionsCircular economy business models which enable second life batteries show lower environmental impacts compared to a new battery when it can partly avoid production of a new battery. Based on the identified technical and market factor affecting this potential, a key message to industry and other organizations is that second life batteries should be chosen over new batteries. This depends on the remaining capacity being satisfactory for the new application, and the investment is not performed because of a low price compared to a new battery. Consequential LCA practitioners adopting a market approach while evaluating battery reuse and repurpose should model and account for the avoided production potential.

Life cycle assessment of eight urban farms and community gardens in France and California

Urban agriculture (UA) is often positioned as an environmentally sustainable food supply for cities. However, life cycle assessments (LCA) measuring environmental impacts of UA show mixed results, because of inconsistent application of LCA and reliance on hypothetical case studies. To address these shortcomings, we performed an LCA of eight urban farms and community gardens in Paris, France and San Francisco, California, USA. We collected primary data from sites representing diverse growing systems (low-intensity open-field to open-air hydroponics) and motivations (education, civic engagement, and commercial production). We found that medium-tech farms, with minimum social engagement had the lowest impacts using a kilogram-based functional unit, but socially-oriented farms had the lowest impacts with an area-based functional unit. Most impacts came from infrastructure (irrigation pipes, hydroponics structures), irrigation, compost, and peat for seedlings. Our findings can help LCA practitioners perform UA LCAs more completely/consistently, and help urban farmers/gardeners target high-environmental-impact practices to optimize.

LCA of Wood Waste Management Systems: Guiding Proposal for the Standardization of Studies Based on a Critical Review

In environmental management, there are many opportunities to improve wood waste (WW) management practices. Life Cycle Assessment (LCA), according to ISO 14040, is a tool used to assess the environmental impacts related to a product throughout its life cycle. Thus, this article aims to propose guidelines for the creation of future LCAs of wood waste management systems in a consistent and standardized way based on the deficiencies and examples found in the studies that comprise the extensive bibliographic review of this research. During the selection of studies, the methodology termed Methodi Ordinatio was used, which considers the three most relevant points to qualify a scientific study: the impact factor; the year of publication; and the number of citations. Fifty (50) articles were identified to create a general map of the literature relevant to the topic under study. We carried out a critical review that highlights the lack of standardization and clarity of the research in this area. For example, in relation to the total number of studies analyzed, 67% did not clarify the type of analysis (attributional or consequential). Several recommendations and perspectives within the LCA of WW management were highlighted, such as the need to analyze impact categories other than climate change and to include economic and social analyses in new studies. In order to leverage all these research opportunities, it is important that LCA practitioners adopt global standardization. In future research, the guiding proposal presented in this study can improve the comparison between scenarios and the consistency of results.

A comparison and methodological proposal for hybrid approaches to quantify environmental impacts: A case study for renewable energies

The transition towards a more sustainable and decarbonised energy system is mandatory for achieving global climate objectives, and counting on proper tools to evaluate sustainability is essential. Among sustainability assessment methodologies, hybrid approaches integrating Input-Output analysis (IOA) and Life Cycle Assessment (LCA) are often proposed to overcome limitations and take advantage of strengths of both methodologies. In this paper we propose a new hybrid tiered approach, named Identification and Subtraction Method (ISM). Through a case study of Concentrated Solar Power (CSP) technology, we test the proposed method assessing seven environmental indicators and compare the results obtained by different methodological approaches: Environmental Extended Multiregional Input-Output (EMRIO), LCA and two hybrid approaches.Results showed that, in general, LCA and EMRIO provide the lowest and uppest impact values, respectively. The ISM method expands the LCA boundaries by including indirect impacts, avoiding double-counting and retaining the technological detail and representativeness of the LCA. The main advantage is the ability to establish with high accuracy the impact coming from the LCA system boundaries. Furthermore, ISM is easy to undertake for LCA practitioners, is a low time-consuming hybrid approach once the LCA and EMRIO models are run, and it does not require the alteration of the IO matrix as other hybrid methods. However, the need to perform the EMRIO and LCA analysis could imply high detailed data needs. An additional limitation of the model is that it is not be able to include partial contributions from EMRIO sectors. The highest differences between results obtained by the different methods are found in the assessment of local impacts and the resources depletion, while the methods tend to agree more on global and regional impacts quantification. However, there are limitations to the implementation of the impact characterization methods that should be borne in mind when comparing the results of the different methods.

Optimal BIM and LCA integration approach for embodied environmental impact assessment

It has been widely acknowledged that applications of building information modeling (BIM) can facilitate the effectiveness of embodied environmental impact assessment of buildings. Various approaches for integrating BIM software and life cycle assessment (LCA) tools have been developed in recent years. However, limited research has been conducted in defining appropriate BIM-LCA integration approaches for embodied environmental impact assessment. To address this issue, this research develops a way of selecting the optimal BIM-LCA integration approach that incorporates the needs of different scenarios for the performance of the integration approach. Three scenarios of environmental impact assessment are designed to demonstrate the application of the proposed way, including 1) environmental impact assessment in early design stage, 2) environmental impact assessment in the detailed design stage, and 3) environmental impact assessment in construction design stage. The demonstration results indicate that the method of “using visual programming languages” is the optimal BIM-LCA integration approach for assessing environmental impacts in the early and construction design stages. The methods of “adopting LCA plugin for BIM-software” and “using visual programming languages” are the optimal approaches for environmental assessment in the scenario of detailed design stages. This research assists LCA practitioners in selecting optimal BIM-LCA integration approaches in different scenarios and further promotes the applications of BIM-LCA integration approaches during the whole design process of a building.

Derivation and assessment of regional electricity generation emission factors in the USA.

Electricity production is one of the largest sources of environmental emissions-especially greenhouse gases (GHGs)-in the USA. Emission factors (EFs) vary from region to region, which requires the use of spatially relevant EF data for electricity production while performing life cycle assessments (LCAs). Uncertainty information, which is sought by LCA practitioners, is rarely supplied with available life cycle inventories (LCIs). To address these challenges, we present a method for collecting data from different sources for electricity generation and environmental emissions; discuss the challenges involved in agglomerating such data; provide relevant suggestions and solutions to merge the information; and calculate EFs for electricity generation processes from various fuel sources for different spatial regions and spatial resolutions. The EFs from the US 2016 Electricity Life Cycle Inventory (eLCI) are analyzed and explored in this study. We also explore the method of uncertainty information derivation for the EFs. We explore the EFs from different technologies across Emissions & Generation Resource Integrated Database (eGRID) regions in the USA. We find that for certain eGRID regions, the same electricity production technology may have worse emissions. This may be a result of the age of the plants in the region, the quality of fuel used, or other underlying factors. Region-wise life cycle impact assessment (LCIA) ISO 14040 impacts for total generation mix activities provide an overview of the total sustainability profile of electricity production in a particular region, rather than only global warming potential (GWP). We also find that, for different LCIA impacts, several eGRID regions are consistently worse than the US average LCIA impact for every unit of electricity generated. This work describes the development of an electricity production LCI at different spatial resolutions by combining and harmonizing information from several databases. The inventory consists of emissions, fuel inputs, and electricity and steam outputs from different electricity production technologies located across various regions of the USA. This LCI for electricity production in the USA will prove to be an enormous resource for all LCA researchers-considering the detailed sources of the information and the breadth of emissions covered by it.

Relative sensitivity value (RSV): A metric for measuring input parameter influence in life cycle assessment modeling.

Life cycle assessment (LCA) is a commonly used tool to quantify life cycle environmental footprints of products. Uncertainty in LCA modeling, particularly from uncertainty in production practices (represented through input parameter arguments), can lead to incorrect conclusions and hamper decision-making. Characterization of uncertainty through stochastic means and sensitivity analysis is utilized in a small fraction of LCA case studies, and the majority of studies default to scenario analysis due to its lower barrier to implementation and its results areeasier to interpret. In this article, we introduce a sensitivity metric, relative sensitivity value (RSV), which allows LCA practitioners to gauge the relative influence of production practices on life cycle impacts in multiple phases and impact categories. Relative sensitivity value bridges the gap between scenario analysis and global sensitivity analysis, and it allows an LCA practitioner to provide an easy-to-interpret metric for quantifying the degree to which incremental changes in production practices influences the life cycle environmental footprint. We present the methodology used to calculate RSV and provide programming code, which can be readily used by an LCA practitioner to calculate RSV for their LCA model. We demonstrate the usage of RSV through a livestock husbandry LCA case study, in which we show how RSV results may be presented and interpreted, and how conclusions regarding production practices may be drawn. Integr Environ Assess Manag 2023;19:547-555. © 2022 SETAC.

A Comprehensive Dynamic Life Cycle Assessment Model: Considering Temporally and Spatially Dependent Variations.

Life cycle assessment (LCA) is a widely-used international environmental evaluation and management method. However, the conventional LCA is in a static context without temporal and spatial variations considered, which fails to bring accurate evaluation values and hinders practical applications. Dynamic LCA research has developed vigorously in the past decade and become a hot topic. However, systematical analysis of spatiotemporal dynamic variations and comprehensive operable dynamic models are still lacking. This study follows LCA paradigm and incorporates time- and space-dependent variations to establish a spatiotemporal dynamic LCA model. The dynamic changes are classified into four types: dynamic foreground elementary flows, dynamic background system, dynamic characterization factors, and dynamic weighting factors. Their potential dynamics and possible quantification methods are analyzed. The dynamic LCA model is applied to a residential building, and significant differences can be observed between dynamic and static assessment results from both temporal and spatial perspectives. This study makes a theoretical contribution by establishing a comprehensive dynamic model with both temporal and spatial variations involved. It is expected to provide practical values for LCA practitioners and help with decision-making and environmental management.