Issues In Life Cycle Assessment Research Articles

Reviewing ISO Compliant Multifunctionality Practices in Environmental Life Cycle Modeling

The standard ISO 14044:2006 defines the hierarchical steps to follow when solving multifunctionality issues in life cycle assessment (LCA). However, the practical implementation of such a hierarchy has been debated for twenty-five years leading to different implementation practices from LCA practitioners. The first part of this study discussed the main steps where the ISO hierarchy has been implemented differently and explored current multifunctionality practices in peer-reviewed studies. A text-mining process was applied to quantitatively assess such practices in the 532 multifunctional case studies found in the literature. In the second part of the study, citation network analysis (CNA) was used to identify the major publications that influenced the development of the multifunctionality-debate in LCA, i.e., the key-route main path. The identified publications were then reviewed to detect the origins of the different practices and their underlying theories. Based on these insights, this study provided some “food for thought” on current practices to move towards consistent methodology. We believe that such an advancement is urgently needed for better positioning LCA as a tool for sustainability decision-making. In particular, consistent allocation practices could be especially beneficial in bioeconomy sectors, where production processes are usually multifunctional, and where current allocation practices are not harmonized yet.

A dynamic weighting system considering temporal variations using the DTT approach in LCA of buildings

Weighting is an important step that supports comparison and decision-making in the LCA (Life Cycle Assessment) of buildings. However, temporal variations of weighting systems have not been adequately studied. Given the increasing demand of addressing time issues in LCA, this study attempts to develop a dynamic weighting system. Three common weighting approaches—expert panel, monetization, and DTT (distance-to-target)—are compared, and the DTT approach is selected for utilization. Temporal variations of emission targets and resource characteristics are considered in the new weighting system, which includes short-term, medium-term, and long-term weighting factors. The dynamic weighting system makes it possible to quantify environmental impacts with temporal-varying environmental policies and planning, and the assessment results could better guide design improvements with various environmental priorities in different periods considered. A residential building is taken as case to test the operability of the new weighting system. The significant difference between the assessment results weighted by the traditional versus the dynamic weighting systems indicates the necessity of considering temporal variations.

Is Unbleached Cotton Better Than Bleached? Exploring the Limits of Life-Cycle Assessment in the Textile Sector

The applicability of life-cycle assessment (LCA) for the textile industry is discussed with a special focus on environmental impact from chemicals. Together with issues of water depletion and energy use, the use of chemicals and their emissions are important environmental considerations for textile products. However, accounting for chemicals is a weak point in LCA methodology and practice. Two research questions were investigated in a case study of hospital garments: 1) whether LCA adds value to assessments of the chemical performance of textile products, and 2) whether inclusion of toxicity issues in LCA affects environmental performance rankings for textile products. It is concluded that the quantitative and holistic tool LCA is useful for environmental decision makers in the textile industry, and becomes more effective when chemical impacts are included. A flexible way forward is demonstrated to meet the challenge of accounting for chemicals in LCAs of textile products.

A contribution to the environmental impact assessment of green water flows

In recent years, numerous efforts have been made to include water-related issues in life cycle assessment (LCA) methodology. This study provides an overview of existing methods that address green water use in LCA. In this overview, we analyse the main features of existing LCA methods used to examine changes in long-term blue water availability caused by variations in green water flows, particularly with respect to inventory, the characterisation model and characterisation factors.Moreover, we propose a method of assessing impacts on terrestrial green water flows (TGWI) and addressing reductions in surface blue water production (RBWP) caused by reductions in surface runoff due to land-use production systems. Both TGWI and RBWP are analysed, taking into account the green water use/atmosphere and green water use/soil interfaces.In this proposed method, the life cycle inventory (LCI) phase considers the net green water flow that leaves the land-use production system, allowing the study of two alternative reference land uses: 1) quasi-natural forest and 2) grasslands/shrublands. In the life cycle impact assessment (LCIA) phase, regional- and species-specific characterisation factors (CFs) for the amount of green water evaporated or transpired are also proposed.To illustrate the applicability of the proposed method, we employed a case study on Eucalyptus globulus stands (first rotation), located in Portugal. The results show that different impacts on terrestrial green water flows and on surface blue water production are obtained depending on the alternative reference land use. Moreover, the case study shows that the method developed can be a useful tool assisting in improved national E. globulus forest planning.

DEALING WITH LCA MODELING FOR THE END OF LIFE OF MECHATRONIC PRODUCTS

This paper discusses end-of-life (EoL) modeling issues in Life Cycle Assessment (LCA), through the application to a domestic cooker hood. Two EoL approaches are applied and discussed, namely the avoided burden and the one recommended by the Product Environmental Footprint (PEF) Guide, presently under testing. While no case studies on PEF application have been published yet, to the best of our knowledge, the scientific community is questioning the robustness and relevance of some methodological aspects, especially the EoL formula. The objective of the work is to provide a case study for supporting the scientific discussion on EoL modeling by: applying the avoided burden approach to the cooker hood EoL; testing the PEF EoL approach on a cooker hood component, the aluminum filter, and compare the results with those obtained from the avoided burden approach; evaluating how both the approaches affect the allocation of burdens/credits associated to recycling. The Global Warming Potential (GWP) and the Abiotic Depletion Potential (ADP) impact categories are investigated. The study points out that the PEF EoL approach delivers higher environmental impacts than the avoided burden one, due to a reduced contribution from the avoided impacts. Overall, the application of the PEF EoL approach is more complex, due to the additional and often not available information needed, such as the recycled content of the materials and the disposal treatments that are avoided when recycled materials are used in the product. Also the structure of the LCA datasets may limit the application of the PEF EoL.

A framework for modelling the transport and deposition of eroded particles towards water systems in a life cycle inventory

Purpose Topsoil erosion due to land use has been characterised as one of the most damaging problems from the perspective of soil-resource depletion, changes in soil fertility and net soil productivity and damage to aquatic ecosystems. On-site environmental damage to topsoil by water erosion has begun to be considered in Life Cycle Assessment (LCA) within the context of ecosystem services. However, a framework for modelling soil erosion by water, addressing off-site deposition in surface water systems, to support life cycle inventory (LCI) modelling is still lacking. The objectives of this paper are to conduct an overview of existing methods addressing topsoil erosion issues in LCA and to develop a framework to support LCI modelling of topsoil erosion, transport and deposition in surface water systems, to establish a procedure for assessing the environmental damage from topsoil erosion on water ecosystems.

Methodological issues in life cycle assessment of mixed-culture polyhydroxyalkanoate production utilising waste as feedstock

Assessing the environmental performance of emerging technologies using life cycle assessment (LCA) can be challenging due to a lack of data in relation to technologies, application areas or other life cycle considerations, or a lack of LCA methodology that address the specific concerns. Nevertheless, LCA can be a valuable tool in the environmental optimisation in the technology development phase. One emerging technology is the mixed-culture production of polyhydroxyalkanoates (PHAs). PHA production by pure microbial cultures has been developed and assessed in several LCAs during the previous decade. Recent developments within mixed-culture PHA production call for environmental assessment to guide in technology development. Mixed-culture PHA production can use the organic content in wastewater as a feedstock; the production may then be integrated with wastewater treatment (WWT) processes. This means that mixed-culture PHA is produced as a by-product from services in the WWT. This article explores different methodological challenges for LCA of mixed-culture PHA production using organic material in wastewater as feedstock. LCAs of both pure- and mixed-culture PHA production were reviewed. Challenges, similarities and differences when assessing PHA production by mixed- or pure-cultures were identified and the resulting implications for methodological choices in LCA were evaluated and illustrated, using a case study with mixed- and pure-culture PHA model production systems, based on literature data. Environmental impacts of processes producing multiple products or services need to be allocated between the different products or services. Such situations occur both in feedstock production and when the studied system is providing multiple functions. The selection of allocation method is shown to determine the LCA results. The type of data used, for electricity in the energy system, is shown to be important for the results, which indicates, a strong regional dependency of results for systems with electricity use as an environmental hot spot. The importance of assessing water use, an environmental impact not assessed by any of the reviewed studies, is highlighted.

Water in life cycle assessment—50th Swiss Discussion Forum on Life Cycle Assessment—Zürich, 4 December 2012

Water use, its impacts and management, have become a focus of attention in the past decade in the context of climate change and increasing consumption (in particular of food and agricultural products) due to a growing global population. Many efforts have been made to include water-related issues in life cycle assessment (LCA) in various ways, from the long-standing eutrophication, acidification, and ecotoxicity methods, to the more recent water consumption aspects. Four years on from the first discussion forum on water in LCA (35th Swiss Discussion Forum on LCA, Zürich, 5 June 2008), numerous developments have occurred, resulting in a rich palette of approaches. Significant challenges still remain, related to the complexity of water systems and ecosystems, and certain impacts are still not considered. New challenges have emerged, such as how to fit these “pieces” together to form a coherent and comprehensive approach for assessing the impacts of water use (both degradative and consumptive). Practice has started to apply certain water consumption-related approaches and an early feedback between practitioners and developers is essential to ensure a harmonious further development. The 50th Swiss Discussion Forum on Life Cycle Assessment (DF-50) gave a brief overview of the current status of water use in LCA, and then focused on the following topics in three main sessions: (1) a selection of recent research developments in the field of impact assessment modeling; (2) identification of new and remaining challenges where future effort could be concentrated, with a focus on spatial and temporal resolution; (3) and experiences and learnings from application in practice. Furthermore, several short presentations addressed the issues of inventory requirements and comparison of impact assessment approaches. The DF-50 was concluded with a discussion workshop, focusing on four issues: which degree of regionalization is desirable, how to address data gaps in inventories, the comparability of different impact assessment approaches, and the pros and cons of including positive impacts (benefits). Numerous recent developments in life cycle impact assessment have tackled impact pathways, spatial and temporal resolutions, and uncertainties. They have lead to an increase of the completeness of impact assessment, but also of its complexity. Although developments have also occurred in inventories, the gap between impact assessment and inventory is challenging, which in turn limits the applicability of the methods. Regionalization is confirmed as an essential aspect in water footprinting; however, its implementation requires concerted effort by impact assessment developers and software developers. Therefore, even though immense progress has been made, it may be time to think of putting the pieces together in order to simplify the applicability of these tools: enabling the support of improvements in companies and policy is the ultimate goal of LCA. The recordings and presentations of the DF-50 are available for download from www.lcaforum.ch.

Generalized Make and Use Framework for Allocation in Life Cycle Assessment

SummaryAllocation in life cycle inventory (LCI) analysis is one of the long‐standing methodological issues in life cycle assessment (LCA). Discussion on allocation among LCA researchers has taken place almost in complete isolation from the series of closely related discussions from the 1960s in the field of input−output economics, regarding the supply and use framework. This article aims at developing a coherent mathematical framework for allocation in LCA by connecting the parallel developments of the LCA and the input−output communities. In doing so, the article shows that the partitioning method in LCA is equivalent to the industry‐technology model in input−output economics, and system expansion in LCA is equivalent to the by‐product‐technology model in input−output output economics. Furthermore, we argue that the commodity‐technology model and the by‐product‐technology model, which have been considered as two different models in input−output economics for more than 40 years, are essentially equivalent when it comes to practical applications. It is shown that the matrix‐based approach used for system expansion successfully solves the endless regression problem that has been raised in LCA literature. A numerical example is introduced to demonstrate the use of allocation models. The relationship of these approaches with consequential and attributional LCA models is also discussed.

Key issues in life cycle assessment of ethanol production from lignocellulosic biomass: Challenges and perspectives

Progressive depletion of conventional fossil fuels with increasing energy consumption and greenhouse gas (GHG) emissions have led to a move towards renewable and sustainable energy sources. Lignocellulosic biomass is available in massive quantities and provides enormous potential for bioethanol production. However, to ascertain optimal biofuel strategies, it is necessary to take into account environmental impacts from cradle to grave. Life cycle assessment (LCA) techniques allow detailed analysis of material and energy fluxes on regional and global scales. This includes indirect inputs to the production process and associated wastes and emissions, and the downstream fate of products in the future. At the same time if not used properly, LCA can lead to incorrect and inappropriate actions on the part of industry and/or policy makers. This paper aims to list key issues for quantifying the use of resources and releases to the environment associated with the entire life cycle of lignocellulosic bioethanol production.

Critical Review: Life-Cycle Inventory Procedures for Long-Term Release of Metals

Life-cycle assessment (LCA) is the method of inventorying, assessing, and interpreting environmental interventions caused by products and product systems through their life cycle. The ecotoxicity of metals has proven a challenge for LCA given metal characteristics such as reversibility of removal processes, speciation, and the effect on bioavailability and ecotoxic effect assessment. Our review focuses on the first part of the ecotoxic impact chain for metals, i.e., the release of metals from solid deposits. According to the principle of temporal justice, sustainability assessment tools such as LCA should accountfor emissions regardless of temporal location distribution. This is in LCA commonly interpreted as leaching until depletion of metals bound in solid wastes under the presumption that infinite time implies infinite weathering. This approach is risk conservative for metals and it hampers the use of LCA to assess remediation projects for soils and sediments contaminated by inorganic substances. We discuss metal significance and inventory issues in LCA, and review existing and proposed approachesto make LCA applicable to metal long-term emission.

Automobile life cycle assessment issues at end-of-life and recycling

Reducing and recycling automobile shredder residue (ASR) are important to improve the recycling rate of end-of-life vehicles (ELVs). In this paper, we discuss the concept of applying life cycle assessment (LCA), LCA case studies (landfill of ASR, energy recovery of ASR), and LCA issues concerning ELVs, and we introduce trends in LCA application to new technologies, aimed at achieving a recycling rate of 95%.

Is it feasible to address indoor climate issues in LCA?

Life cycle assessment (LCA) is frequently used as a tool for environmental assessment of buildings and building products. Generally, the main focus of LCA is the impact on the regional and global external environment. However, there are important environmental problems related to buildings that arise locally in connection with the indoor environment, such as effects on human health. The approaches of LCA, measurements of emissions from building materials, and indoor climate assessment were studied to see how they relate to each other from a methodological point of view, using volatile organic compound (VOC) emissions as an example. The possibility of including indoor climate issues as an impact category in LCA of building products was investigated. Only very limited aspects of the indoor climate could be addressed in LCA; thus, indoor climate issues are preferably dealt with separately.

Life-cycle assessment and its relevance to Australian forestry and wood product industries

Summary Life-cycle assessment (LCA) is considered the most objective method for evaluating the environmental burden of products or services. LCA is a cradle-to-grave analysis of the environmental impacts of a product system that includes all stages, from the initial supply of raw materials, through to product disposal at the end of its useful life. This paper summarises the general approach of the method and current applications world wide. Recent developments and key issues in LCAs of forestry and wood product industries (timber, composite wood products, and paper) are outlined. Advantages and disadvantages of LCA are discussed, along with ways Australian forestry and wood product industries could contribute to LCA development. The private sector uses LCA for product marketing; designing environmentally low-impact products; and improving the environmental record of current product systems. The public sector applies LCA to regulate stages of product systems, such as packaging; assess environmental and development programs; and in eco-labelling. LCA's main advantage is its complete and global approach to environmental assessment. Problems with the method are the large amount of data required and time needed to conduct a study. An Australian database for the forest and wood products industries would make LCA considerably easier and cheaper.