Integration of life cycle assessment in the environmental information system

LIFE cycle assessment (LCA) of photovoltaic (PV) electric power generation investigates the energy requirement over the whole manufacturing and operational phases. Existing LCA results of PV have been based on process LCA method which considers the material and energy flow on physical level. This method has an obvious shortcoming of limited boundary. Many processes over the life cycle of PV are excluded from the process LCA, such as producing chemicals, manufacturing facilities and equipment, services and transportation. This paper proposes a step-by-step hybrid LCA method to mitigate the error induced by process LCA of PV. Besides the energy requirement analyzed by process LCA, there are energy requirements analyzed by economic input-output (EIO) LCA. In EIO LCA, the energy requirements fall into two categories--additive and remaining value. The gross energy requirements (GER) from the hybrid LCA result is 3240MJ/m2 for multi-crystalline silicon PV module. This result is higher than previous results: 2300MJ/m2 [1] and 3600MJ/m2 [2]. It is not surprising, because the hybrid LCA covers the whole spectrum from direct energy requirement in manufacturing process, embodied energy in chemicals and equipments to transportation and services, as well as the energy requirements in upstream manufacturing process. While the LCA results of previous study are from process analysis with a limited boundary.

Despite the potential value it offers, integration of life cycle assessment (LCA) into the development of environmental public policy has been limited. This paper researches potential barriers that may be limiting the use of LCA in public policy development, and considers process opportunities to increase this application. Research presented in this paper is primarily derived from reviews of existing literature and case studies, as well as interviews with key public policy officials with LCA experience. Direct experience of the author in LCA projects with public policy elements has also contributed to approaches and conclusions. LCAs have historically been applied within a rational framework, with experts conducting the analysis and presenting results to decision-makers for application to public policy development. This segmented approach has resulted in limited incorporation of LCA results or even a broader approach of life cycle thinking within the public policy development process. Barriers that limit the application of LCA within the public policy development process range from lack of technical knowledge and LCA understanding on the part of policy makers, to a lack of trust in LCA process and results. Many of the identified barriers suggest that the failure of LCAs to contribute positively to public policy development is due to the process within which the LCA is being incorporated, rather than technical problems in the LCA itself. Overcoming the barriers to effective use of LCAs in public policy development will require a more normative approach to the LCA process that incorporates a broad group of stakeholders at all stages of the assessment. Specifically, a set of recommendations have been developed to produce a more inclusive and effective process. In an effort to effectively incorporate LCA within the overall public policy decision-making process, the decision-making process should incorporate a multi-disciplinary approach that includes a range of stakeholders and public policy decision-makers in a collaborative process. One of the most important aspects of incorporating LCA into public policy decisions is to encourage life cycle thinking among policy makers. Considering the life cycle implications will result in more informed and thoughtful decisions, even if a full LCA is not undertaken.

Who Cares About Life Cycle Assessment?

The body of life cycle assessment (LCA) literature is vast and has grown over the last decade at a dauntingly rapid rate. Many LCAs have been published on the same or very similar technologies or products, in some cases leading to hundreds of publications. One result is the impression among decision makers that LCAs are inconclusive, owing to perceived and real variability in published estimates of life cycle impacts. Despite the extensive available literature and policy need formore conclusive assessments, only modest attempts have been made to synthesize previous research. A significant challenge to doing so are differences in characteristics of the considered technologies and inconsistencies in methodological choices (e.g., system boundaries, coproduct allocation, and impact assessment methods) among the studies that hamper easy comparisons and related decision support. An emerging trend is meta-analysis of a set of results from LCAs, which has the potential to clarify the impacts of a particular technology, process, product, or material and produce more robust and policy-relevant results. Meta-analysis in this context is defined here as an analysis of a set of published LCA results to estimate a single or multiple impacts for a single technology or a technology category, either in a statisticalmore » sense (e.g., following the practice in the biomedical sciences) or by quantitative adjustment of the underlying studies to make them more methodologically consistent. One example of the latter approach was published in Science by Farrell and colleagues (2006) clarifying the net energy and greenhouse gas (GHG) emissions of ethanol, in which adjustments included the addition of coproduct credit, the addition and subtraction of processes within the system boundary, and a reconciliation of differences in the definition of net energy metrics. Such adjustments therefore provide an even playing field on which all studies can be considered and at the same time specify the conditions of the playing field itself. Understanding the conditions under which a meta-analysis was conducted is important for proper interpretation of both the magnitude and variability in results. This special supplemental issue of the Journal of Industrial Ecology includes 12 high-quality metaanalyses and critical reviews of LCAs that advance understanding of the life cycle environmental impacts of different technologies, processes, products, and materials. Also published are three contributions on methodology and related discussions of the role of meta-analysis in LCA. The goal of this special supplemental issue is to contribute to the state of the science in LCA beyond the core practice of producing independent studies on specific products or technologies by highlighting the ability of meta-analysis of LCAs to advance understanding in areas of extensive existing literature. The inspiration for the issue came from a series of meta-analyses of life cycle GHG emissions from electricity generation technologies based on research from the LCA Harmonization Project of the National Renewable Energy Laboratory (NREL), a laboratory of the U.S. Department of Energy, which also provided financial support for this special supplemental issue. (See the editorial from this special supplemental issue [Lifset 2012], which introduces this supplemental issue and discusses the origins, funding, peer review, and other aspects.) The first article on reporting considerations for meta-analyses/critical reviews for LCA is from Heath and Mann (2012), who describe the methods used and experience gained in NREL's LCA Harmonization Project, which produced six of the studies in this special supplemental issue. Their harmonization approach adapts key features of systematic review to identify and screen published LCAs followed by a meta-analytical procedure to adjust published estimates to ones based on a consistent set of methods and assumptions to allow interstudy comparisons and conclusions to be made. In a second study on methods, Zumsteg and colleagues (2012) propose a checklist for a standardized technique to assist in conducting and reporting systematic reviews of LCAs, including meta-analysis, that is based on a framework used in evidence-based medicine. Widespread use of such a checklist would facilitate planning successful reviews, improve the ability to identify systematic reviews in literature searches, ease the ability to update content in future reviews, and allow more transparency of methods to ease peer review and more appropriately generalize findings. Finally, Zamagni and colleagues (2012) propose an approach, inspired by a meta-analysis, for categorizing main methodological topics, reconciling diverging methodological developments, and identifying future research directions in LCA. Their procedure involves the carrying out of a literature review on articles selected according to predefined criteria.« less

Life-cycle assessment (LCA) is an established methodology that can provide decision-makers with comprehensive data on the environmental impacts of products and processes during the entire life cycle. However, the literature on building LCAs consists of highly varying results between the studies, even when the assessed buildings are very similar. This makes it doubtful if LCA can actually produce reliable data for supporting policy-making in the building sector. However, no prior reviews looking into this issue in the building sector exist. This study includes an extensive literature review of LCA studies on the pre-use phase of buildings. The purpose of this study is to analyze the variation between the results of different studies and find out whether the differences can be explained by the contextual differences or if it is actually the methodological choices that cause the extremely high variation. We present 116 cases from 47 scientific articles and reports that used process LCA, input–output (IO) LCA or hybrid LCA to study the construction-phase GHG emissions of buildings. The results of the reviewed studies vary between 0.03 and 2.00 tons of GHG emissions per gross area. The lowest was assessed with process LCA and highest with IO LCA, and in general the lower end was found to be dominated by process LCA studies and the higher end by IO LCA studies, hybrid LCAs being placed in between. In general, it is the methodological issues and subjective choices of the LCA practitioner that cause the vast majority of the huge variance in the results. It thus seems that currently the published building LCAs do not offer solid background information for policy-making without deep understanding of the premises of a certain study and good methodological knowledge.

Integrating life cycle assessment and health risk assessment of direct and indirect exposure (case study: A combined cycle power plant)

Integration of techno-economic and life cycle assessment: Defining and applying integration types for chemical technology development

Assessing the greenhouse gas mitigation potential of urban precincts with hybrid life cycle assessment

This thesis is the first complete and transparent study of the life-cycle environmental impacts of semiconductor chips using process-level data, as well as the first analysis of the changes in these impacts over time. LCA of complementary metal oxide semiconductor (CMOS) logic, flash memory and dynamic random access memory (DRAM) are presented. CMOS logic is the most common form of digital logic used today. This thesis provides a life cycle assessment for CMOS chips over 7 technology generations with the purpose of comparing impacts by life cycle stage, examining their trends over time and evaluating their sensitivity to data uncertainty and changes in production metrics such as yield. A hybrid life cycle assessment (LCA) model is used; Wafer production, electricity generation, water supply and certain materials are represented by process LCA data, while the remaining materials are described using economic input-output (EIO) LCA methods. It is determined that, in the case of CMOS logic, life-cycle impacts in all but one category are dominated by the use phase, and impacts are most sensitive to those variables which define use phase energy demand (chip power demand, usage patterns, power supply efficiency and chip lifetime). Using the same methodology, LCA of flash memory over 5 technology generations is presented. The most recent generation of flash memory is compared with magnetic storage, using a laptop hard-drive as a functional unit, and it is determined that in most impact categories, a flash-based drive will result in fewer impacts. Life-cycle impacts of DRAM, over 6 technology generations, are presented using as the functional unit, the memory requirements a popular operating system in each year of production. The influence of the choice of functional unit on results in semiconductor LCA is examined, and it is argued that functional unit is best defined as a computational power or memory capacity required for a given function, within a set time period. The LCA impact and inventory results for these three types of semiconductor products allow more accurate assessment of the environmental benefit or costs of information technology relative to traditional products and services.

Circular utilization of urban tree waste contributes to the mitigation of climate change and eutrophication

Despite the ever-growing body of life cycle assessment (LCA) literature on electricity generation technologies, inconsistent methods and assumptions hamper comparison across studies and pooling of published results. Synthesis of the body of previous research is necessary to generate robust results to assess and compare environmental performance of different energy technologies for the benefit of policy makers, managers, investors, and citizens. With funding from the U.S. Department of Energy, the National Renewable Energy Laboratory initiated the LCA Harmonization Project in an effort to rigorously leverage the numerous individual studies to develop collective insights. The goals of this project were to: (1) understand the range of published results of LCAs of electricity generation technologies, (2) reduce the variability in published results that stem from inconsistent methods and assumptions, and (3) clarify the central tendency of published estimates to make the collective results of LCAs available to decision makers in the near term. The LCA Harmonization Project's initial focus was evaluating life cycle greenhouse gas (GHG) emissions from electricity generation technologies. Six articles from this first phase of the project are presented in a special supplemental issue of the Journal of Industrial Ecology on Meta-Analysis of LCA: coal (Whitaker et al. 2012), concentratingmore » solar power (Burkhardt et al. 2012), crystalline silicon photovoltaics (PVs) (Hsu et al. 2012), thin-film PVs (Kim et al. 2012), nuclear (Warner and Heath 2012), and wind (Dolan and Heath 2012). Harmonization is a meta-analytical approach that addresses inconsistency in methods and assumptions of previously published life cycle impact estimates. It has been applied in a rigorous manner to estimates of life cycle GHG emissions from many categories of electricity generation technologies in articles that appear in this special supplemental supplemental issue, reducing the variability and clarifying the central tendency of those estimates in ways useful for decision makers and analysts. Each article took a slightly different approach, demonstrating the flexibility of the harmonization approach. Each article also discusses limitations of the current research, and the state of knowledge and of harmonization, pointing toward a path of extending and improving the meta-analysis of LCAs.« less

Charting the Future of Life Cycle Sustainability Assessment: A Special Issue

Hybrid life cycle assessment (LCA) does not necessarily yield more accurate results than process-based LCA

This study conducted a systematic literature review of the technical aspects and methodological choices in life cycle assessment (LCA) studies of the use of hydrogen for road transport. More than 70 scientific papers published during 2000–2021 were reviewed, in which more than 350 case studies of the use of hydrogen in the automotive sector were found. Only some studies used hybrid LCA and energetic input–output LCA, whereas most studies addressed attributional process-based LCA. A categorization based on the life cycle scope distinguished case studies that addressed the well-to-tank (WTT), well-to-wheel (WTW), and complete life cycle approaches. Furthermore, based on the hydrogen production process, these case studies were classified into four categories: thermochemical, electrochemical, thermal–electrochemical, and biochemical. Moreover, based on the hydrogen production site, the case studies were classified as centralized, on-site, and on-board. The fuel cell vehicle passenger car was the most commonly used vehicle. The functional unit for the WTT studies was mostly mass or energy, and vehicle distance for the WTW and complete life cycle studies. Global warming potential (GWP) and energy consumption were the most influential categories. Apart from the Greenhouse Gases, Regulated Emissions, and Energy Use in Transportation model and the Intergovernmental Panel on Climate Change for assessment of the GWP, the Centrum voor Milieukunde Leiden method was most widely used in other impact categories. Most of the articles under review were comparative LCA studies on different hydrogen pathways and powertrains. The findings provide baseline data not only for large-scale applications, but also for improving the efficiency of hydrogen use in road transport.

In the light of anthropogenic resource depletion and the resulting influences on the greenhouse effect as well as globally occurring famine, food waste has garnered increased public interest in recent years. The aim of this study is to analyze the environmental impacts of food waste and to determine to what extent consumers’ behavior influences the environmental burden of food consumption in households. A life cycle assessment (LCA) study of three food products is conducted, following the ISO 14040/44 life cycle assessment guidelines. This study addresses the impact categories climate change (GWP100), eutrophication (EP), and acidification (AP). Primary energy demand (PED) is also calculated. For adequate representation of consumer behavior, scenarios based on various consumer types are generated in the customer stage. The customer stage includes the food-related activities: shopping, storage, preparation, and disposal of food products as well as the disposal of the sales packaging. If the consumer acts careless towards the environment, the customer stage appears as the main hotspot in the LCA of food products. The environmental impact of food products can be reduced in the customer stage by an environmentally conscious consumer. Shopping has the highest effect on the evaluated impact categories and the PED. Additionally, consumers can reduce the resulting emissions by decreasing the electric energy demand, particularly concerning food storage or preparation. Moreover, results show that the avoidance of wasting unconsumed food can reduce the environmental impact significantly. Results of this study show that the influence of consumer behavior on the LCA results is important. The customer stage of food products should not be overlooked in LCA studies. To enable comparison among results of other LCA studies, the LCA community needs to develop a common methodology for modeling consumer behavior.