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1.
The newly emerging LCA standards provide an opportunity to review and improve upon the current LCA methodology. As more industrial practitioners enter the arena, the opportunity arises to not only demand environmental improvement from industrial service and product providers but also to fill LCA data gaps. A framework is suggested for improvement in the current LCA framework that focuses on the business relationships of the industrial practitioner. The framework seeks to promote environmental improvement from industrial sectors through the identification of state-of-the-art technologies used throughout a life cycle. Basing LCAs on the best performers in an industry will create a market for a high level of environmental performance, disperse the responsibility of inventory data gathering, and improve upon the advancements already anticipated through the widespread application of LCA. 相似文献
2.
Purpose While the application of Life Cycle Assessment (LCA) to lubricants can be considered fully operational for general purposes outside the lubricants industry, where Life Cycle Inventories (LCIs) of mineral and synthetic base oils can be used interchangeably and where additives can be excluded, this is not the case for research and development purposes within the industry. Previous LCAs of base oils are not sufficiently detailed and comprehensive for R&D purposes, and there are no LCAs of lube additives and fully formulated lubricants. The aim of this paper is to integrate and expand previous LCAs of base oils and to investigate on the contribution of lube additives to the environmental impacts of a fully formulated lubricant. Materials and methods This study considers three base oils (mineral, poly-alpha-olefins (PAO) and hydrocracked) and a set of lubricating additives typically used in fully formulated engine oil. The LCA model is based on both industry and literature data. Results and discussion Trends in the lubricants industry towards more sophisticated base oils correspond to remarkably higher environmental impacts per kilogram of product but lead to reduced impacts per kilometre. The contribution of additives to the life cycle impacts of commercial lube oil was found to be remarkably high for some impact categories (nearly 35?% for global warming). Conclusions As base oil is concerned, this study made the point on data availability and provided a contribution in order to integrate and expand previous LCAs of mineral base oil and PAO. On the side of additives, the main conclusion is that in modern lubricants, the contribution of additives in terms of environmental impact can be remarkably high and, therefore, they should not be excluded. 相似文献
3.
Purpose The purpose of this project was to provide a parameterized LCA tool that allows performing site specific life cycle assessments for different wind energy converter types by varying a limited number of relevant parameters. Hereby, it addresses the limited transferability of WEC LCA results to other sites as well as the increasing demand for such data. Methods Basis of the work was an extensive primary data collection at the respective production facilities and other relevant stakeholders like site assessment, service etc. Most of the required data was available at first hand and was completed with data from literature and LCA databases. Based on this data, a complex parameterized material flow model has been built and different product variants have been pre-defined within the model, including relevant production processes and upstream. The pre-definition of these product variants allows reducing the minimum number of parameters that need to be configured for site specific LCAs from a total of over 330 to just nine parameters. Results and conclusions In the future, choosing the right type of technology for specific sites will become more important; especially in the face of increasing land use conflicts and increasing competition between renewable energy technologies. Site and technology specific LCAs prove to be a valuable tool for this assessment. Tools like the presented significantly reduce the effort required for performing these LCAs. Additionally, they can be used for various other purposes like environmental assessments of different repowering scenarios and eco design. 相似文献
4.
PurposeDue to the urgency and the magnitude of the environmental problems caused by food supply chains, it is important that the recommendations for packaging improvements given in life cycle assessment (LCA) studies of food rest on a balanced consideration of all relevant environmental impacts of packaging. The purpose of this article is to analyse the extent to which food LCAs include the indirect environmental impact of packaging in parallel to its direct impact. While the direct environmental impact of food packaging is the impact caused by packaging materials’ production and end-of-life, its indirect environmental impact is caused by its influence on the food product’s life cycle, e.g. by its influence on food waste and on logistical efficiency. MethodsThe article presents a review of 32 food LCAs published in peer-reviewed scientific journals over the last decade. The steps of the food product’s life cycle that contribute to the direct and indirect environmental impacts of packaging provide the overall structure of the analytical framework used for the review. Three aspects in the selected food LCAs were analysed: (1) the defined scope of the LCAs, (2) the sensitivity and/or scenario analyses and (3) the conclusions and recommendations. Results and discussionWhile in packaging LCA literature, there is a trend towards a more systematic consideration of the indirect environmental impact of packaging, it is unclear how food LCAs handle this aspect. The results of the review show that the choices regarding scope and sensitivities/scenarios made in food LCAs and their conclusions about packaging focus on the direct environmental impact of packaging. While it is clear that not all food LCAs need to analyse packaging in detail, this article identifies opportunities to increase the validity of packaging-related conclusions in food LCAs and provides specific recommendations for packaging-related food LCA methodology. ConclusionsOverall, we conclude that the indirect environmental impact of packaging is insufficiently considered in current food LCA practice. Based on these results, this article calls for a more systematic consideration of the indirect environmental impact of packaging in future food LCAs. In addition, it identifies a need for more packaging research that can provide the empirical data that many food LCA practitioners currently lack. In particular, LCA practitioners would benefit if there were more knowledge and data available about the influence of certain packaging characteristics (e.g. shape, weight and type of material) on consumer behaviour. 相似文献
5.
This article is a summary of my dissertation in which LCA was applied to food products and production systems. The overall
objectives were: (1) to learn more about the feasibility and limitations of LCAs of systems for the production and consumption
of foods (food systems); and (2) to generate information on the environmental impact of such systems. Case studies of tomato
ketchup and white bread were carried out. The main conclusion is that LCA is very valuable for incorporating environmental
aspects in the development of more sustainable food systems. One of the major problems encountered was the great scarcity
of environmental data. It was found that there is a need for simplified methods that can be used as a compass to show the
direction towards sustainability. Accordingly, the feasibility of combinng the concept of sustainabiliry principles and LCA
for product development was examined and discussed. This combination was found to yield a simplified method well suited for
screening analysis and product development. 相似文献
6.
Goal, Scope and Background Traditionally, comparative life cycle assessments (LCA) have not considered rebound effects, for instance in case of significant
price differences among the compared products. No justifications have been made for this delimitation in scope. This article
shows that price differences and the consequent effects of marginal consumer expenditure may influence the conclusions of
comparative LCA significantly. We also show that considerations about rebound effects of price differences can be included
in LCAs.
Methods The direct rebound effect of a price difference is marginal consumption. Based on statistical data on private consumption
in different income groups (Statistics Denmark 2005a, 2005b), the present article provides an estimate of how an average Danish
household will spend an additional 1 DKK for further consumer goods, when the household has gained money from choosing a cheaper
product alternative. The approach is to use marginal income changes and the following changes in consumption patterns as an
expression for marginal consumption. Secondly, the environmental impact potentials related to this marginal consumption are
estimated by the use of environmental impact intensity data from an IO-LCA database (Weidema et al. 2005). Finally, it is
discussed whether, and in which ways the conclusions of comparative LCAs can be affected by including the price difference
between product alternatives. This is elucidated in a case study of a comparative LCA screening of two different kinds of
Danish cheese products (Fricke et al. 2004).
Results Car purchase and driving, use and maintenance of dwelling, clothing purchase and insurance constitutes the largest percentages
of the marginal consumption. In a case study of two cheeses, the including the impact potentials related to the price difference
results in significant changes in the total impact potentials. Considering the relatively small price difference of the two
products, it is likely also to have a significant influence on the results of comparative LCAs more generally.
Discussion The influence of marginal consumption in comparative LCAs is relevant to consider in situations with large differences in
the price of the product alternatives being compared, and in situations with minor differences in the impact potentials related
to the alternatives. However, different uncertainties are linked to determining the pattern for marginal consumption and the
environmental impact potential related to this. These are first of all related to the method used, but also include inaccurate
data of consumption in households, aggregation and weighting of income groups, aggregation of product groups, estimation and
size of the price difference, and the general applicability of the results.
Conclusion Incorporating marginal consumption in consequential LCAs is possible in practice. In the case study used, including the rebound
effects of the price difference has a significant influence on the result of the comparative LCA, as the result for the impact
categories acidification and nutrient enrichment changes in favour of the expensive product.
Recommendations and Perspectives It is recommended that the rebound effects of price differences should be included more frequently in LCAs. In order to ensure
this, further research in marginal consumption and investment patterns and IO data for different countries or regions is required.
Furthermore, this study does not consider the economic distributional consequences of buying an expensive product instead
of a cheaper product (e.g. related to how the profit is spent by those who provided the product). It should also be noted,
that more expensive products not necessarily result in less consumption, as those who provided the product also will spend
the money they have earned from the sale. Ideally, these consequences should also be further investigated. Likewise, the development
of databases to include marginal consumption in PC-tools is needed. In general, considerations of marginal consumption would
favour expensive product alternatives, depending, however, on the type of consumer.
ESS-Submission Editor: Dr. David Hunkeler (david.hunkeler@aquaplustech.ch) 相似文献
7.
This paper deals with the question of whether Life Cycle Assessments (LCAs), with their focus on objective and quantitative
results, are the best way to support public policy processes. The public policy making process is characterized as a continuous
discoursive struggle. Criteria are defined to distinguish between good and bad public policy discourses to judge the effects
of LCA on the public policy process. Many policy scientists argue that methodologies that emphasize quantification and the
use of formal methods are not beneficial for sound public policy making. An empirical report of the role LCAs played in public
policy making processes on PVC and chlorine in the Netherlands is made to evaluate the contribution of LCAs to public policy
making processes and to identify the main limitations of the current LCA methodologies and practices. It appears that political
actors tend to use LCAs in a polarizing way. LCAs are easily misused due to their apparent objectivity, and the quantitative
and black box nature of their results. LCAs contain an implicit, normative frame that does not match the environmentalists’
perception on the kind of evidence needed on toxic effects of organochlorines, which reduced the open nature of the Dutch
PVC debate. It is recommended to develop a methodology for product evaluation that approaches the issue in a more open and
emergent way to prevent “premature closure” of the analysis. It is expected that a focus on the development of balanced, rich
arguments on facts and values in the study process will be more fruitful than the calculation of integral, quantitative indicators. 相似文献
8.
The human health impact of fiber reinforced polymer (FRP) composite materials manufactured by the pultrusion industry is not fully understood. In particular, it is unclear whether the human health impact of toxic chemicals present in low concentrations in fire retardant pultruded FRP materials is disproportionately high. This impact may be an important criterion when making boundary selection decisions in the life cycle assessment (LCA) of these materials. The North American pultrusion industry was surveyed to determine resin mix concentration levels and workplace inhalation toxicity exposure levels. LCAs were then conducted on three building panel resin mixes to determine whether the human health impact of toxic chemicals used in the mixes was low enough to exclude the chemicals from the life cycle inventory (LCI) boundary. The first resin mix represented a typical pultruded product, the second mix removed toxic chemicals present in small concentrations, and the third mix replaced toxic chemicals present in small concentrations with a nontoxic chemical. Results showed that toxicity levels fell below exposure limits and no significant difference in human health impact existed among the LCAs. The research concludes that human health impact is a useful criterion when defining an LCI boundary. Toxic chemicals present in small concentrations in pultruded FRP materials may be excluded from the LCI boundary, as their human health impacts are low. Because these levels are marginal in North American pultrusion factories, no changes in resin mixes are recommended for the pultrusion industry. 相似文献
9.
Cold reactive lymphocytotoxic antibodies (LCA) are more reactive in cold than at 37 degrees C and occur following infection, immunization or vaccination and in various autoimmune diseases. In the present study, LCA activity against T and B-lymphocytes has been investigated in patients with pulmonary tuberculosis (PTB), their various clinical sub-groups and consanguineous relatives. Further, the relevance of HLA factors in LCA activity was analyzed. The sera from 144 PTB patients, 52 family contacts and 52 healthy individuals were tested for presence of LCAs by a modified two-stage NIH microlymphocytotoxicity assay. A significant increase in LCA activity against both T (32.6% vs 5.7%, P < 0.0001) and B (59.7% vs 13.4%, P < 0.0000001) cells was observed in PTB patients as compared to healthy controls. There was no correlation between serum LCA activity and sputum acid-fast bacilli status. However, only B cell LCAs revealed significant increase in parallel to disease advancement as assessed by X-ray chest examination. Further, LCA activity was more pronounced in drug responders than drug failure group of patients. No significant difference in the distribution of HLA class I and class II antigens was observed between LCA positive and LCA negative patients. However, panel cells carrying HLA-A1, -A11 and -DR3 were often found reactive in LCA positive patient sera. In household family contacts, LCAs were significantly increased only against B cells as compared to healthy controls (38.4% vs 13.4%, P < 0.01). This study suggests that Mycobacterium tuberculosis infection/exposure could account for the occurrence of LCAs in pulmonary tuberculosis and the strength of these antibodies is related to disease severity and the extent of lung involvement. 相似文献
10.
Goal, Scope and Background
Procurement in public and non-public organisations has the potential to influence product development towards more environmentally
friendly products. This article focuses on public procurement with procurement in Swedish defence as a special case. In 2003,
public procurement in Sweden was 28% of the GDP. In the Swedish defence sector the amount was 2% of the GDP. The total emissions
from the sector were of the same order of magnitude as from waste treatment (2% of Sweden's emissions). According to an appropriation
letter from the Ministry of Defence in 1998, the Swedish Armed Forces (SAF) and the Swedish Defence Materiel Administration
(FMV) are required to take environmental issues into consideration during the entire process of acquiring defence materiel.
Environmental aspects are considered today, but without a life-cycle perspective.
- The aims of this article are to recommend suitable tools for taking environmental concerns into account, considering a product's
life-cycle, in the procurement process for defence materiel in Sweden; to make suggestions for how these tools could be used
in the acquisition process; and to evaluate these suggestions through interviews with actors in the acquisition process. The
procurement process does not include aspects specific to Swedish defence, and it is therefore likely to be comparable to processes
in other countries.
Methods
The method involved a study of current literature and interviews with various actors in the acquisition process. The life
cycle methods considered were quantitative Life Cycle Assessments, a simplified LCA-method called the MECO method and Life
Cycle Costing (LCC).
Results and Discussion
Methodology recommendations for quantitative LCA and simplified LCA are presented in the article, as well as suggestions on
how to integrate LCA methods in the acquisition process. We identified four areas for use for LCA in the acquisition process:
to learn about environmental aspects of the product; to fulfil requirements from customers; to set environmental requirements
and to choose between alternatives. Therefore, tools such as LCAs are useful in several steps in the acquisition process.
Conclusion
From the interviews, it became clear that the actors in the acquisition process think that environmental aspects should be
included early in the process. The actors are interested in using LCA methods, but there is a need for an initiative from
one or several of them if the method is to be used regularly in the process. Environmental and acquisition issues are handled
with very little interaction in the controlling and ordering organisation. An integration of environmental and acquisition
parts in these organisations is probably needed in order to integrate environmental aspects in general and life-cycle thinking
in particular. Other difficulties identified are costs and time constraints.
Recommendation and Perspective
In order to include the most significant aspects when procuring materiel, it is important to consider the whole life-cycle
of the products. Our major recommendation is that the defence sector should work systematically through different product
groups. For each product group, quantitative, traditional LCAs or simplified LCAs (in this case modified MECOs) should be
performed for reference products within each product group. The results should be an identification of critical aspects in
the life-cycles of the products. The studies will also form a database that can be used when making new LCAs. This knowledge
should then be used when writing specifications of what to procure and setting criteria for procurement. The reports should
be publicly available to allow reviews and discussions of results. To make the work more cost-effective, international co-operation
should be sought. In addition, LCAs can also be performed as an integrated part of the acquisition process in specific cases. 相似文献
11.
Life Cycle Assessment (LCA) methodology evaluates holistically the environmental consequences of a product system or activity,
by quantifying the energy and materials used, the wastes released to the environment, and assessing the environmental impacts
of those energy, materials and wastes. Despite the international focus on environmental impact and LCA, the quality of the
underlying life cycle inventory data is at least as, if not more, important than the more qualitative LCA process.
This work presents an option to generate gate-to-gate life cycle information of chemical substances, based on a transparent
methodology of chemical engineering process design (an ab initio approach). In the broader concept of a Life Cycle Inventory
(LCI), the information of each gate-to-gate module can be linked accordingly in a production chain, including the extraction
of raw materials, transportation, disposal, reuse, etc. to provide a full cradle to gate evaluation. The goal of this article
is to explain the methodology rather than to provide a tutorial on the techniques used. This methodology aims to help the
LCA practitioner to obtain a fair and transparent estimate of LCI data when the information is not readily available from
industry or literature. Results of gate-to-gate life cycle information generated using the cited methodology are presented
as a case study.
It has been our experience that both LCI and LCA information provide valuable means of understanding the net environmental
consequence of any technology. The LCI information from this methodology can be used more directly in exploring engineering
and chemistry changes to improve manufacturing processes. The LCA information can be used to set broader policy and to look
at more macro improvements for the environment. 相似文献
12.
Purpose Life cycle assessment (LCA) is a tool that can be utilized to holistically evaluate novel trends in the construction industry and the associated environmental impacts. Green labels are awarded by several organizations based on single or multiple attributes. The use of multi-criteria labels is a good start to the labeling process as opposed to single criteria labels that ignore a majority of impacts from products. Life cycle thinking, in theory, has the potential to improve the environmental impacts of labeling systems. However, LCA databases currently are lacking in detailed information about products or sometimes provide conflicting information. Method This study compares generic and green-labeled carpets, paints, and linoleum flooring using the Building for Environmental and Economic Sustainability (BEES) LCA database. The results from these comparisons are not intuitive and are contradictory in several impact categories with respect to the greenness of the product. Other data sources such as environmental product declarations and ecoinvent are also compared with the BEES data to compare the results and display the disparity in the databases. Results This study shows that partial LCAs focused on the production and transportation phase help in identifying improvements in the product itself and improving the manufacturing process but the results are uncertain and dependent upon the source or database. Inconsistencies in the data and missing categories add to the ambiguity in LCA results. Conclusions While life cycle thinking in concept can improve the green labeling systems available, LCA data is lacking. Therefore, LCA data and tools need to improve to support and enable market trends. 相似文献
13.
Life Cycle Assessments (LCAs) frequently do not contribute to sustainable development because product alternatives with a
truly low environmental burden are not included in the assessment. As a result, environmentally-friendly alternatives are
not uncovered, although much effort has been put into collecting inventory data and making an impact assessment. Part of this
problem is caused by the defensive use of LCAs. Companies eager to show that their product is not too bad for the environment
prefer to compare their product with alternatives that are not very promising in an environmental sense. To (mis)use LCAs
in this way is quite easy, because the LCA methodology and handbooks provide few guidelines and little advice on how to generate
and select adequate alternatives. An analysis of the problems related to the alternatives is given using insights drawn from
the field of policy analysis — a field in which methodological rules for the generation of alternatives in policy studies
have been developed — ecodesign and the LCA discipline, and measures to reduce the problems are developed. Explicating the
different steps in the determination of alternatives in the goal and scope formulation stage of an LCA process, and the development
of a toolbox for this activity, would certainly improve the quality of the selection of alternatives. Furthermore, involving
stakeholders and a group of experts in the generation and selection process will increase the variety and relevance of alternatives,
and the social support for alternatives. 相似文献
14.
In 1991, the Nordic Council of Ministers initiated a project on LCA. The objectives of the project have been to develop a Code of Practise for LCA built on Nordic consensus, to provide industry and other practitioners with a set of guidelines for LCA, mainly in “key issue identification” LCAs and to influence the international discussion on the subject. The final phase of the project is now being finished, resulting in Guidelines for LCA, which arc presented here briefly. Important topics are system boundary setting, cutoff criteria, allocations, data quality and impact assessment methods. 相似文献
15.
Purpose Several articles within the area of green chemistry often promote new techniques or products as ‘green’ or ‘more environmentally benign’ than their conventional counterpart although these articles often do not quantitatively assess the environmental performance. In order to do this, life cycle assessment (LCA) is a valuable methodology. However, on the planning stage, a full-scale LCA is considered to be too time consuming and complicated. Two reasons for this have been recognised, the method is too comprehensive and it is hard to find inventory data. In this review, key parameters are presented with the purpose to reduce the time-consuming steps in LCA. Methods In this review, several LCAs of so-called ‘green chemicals’ are analysed and key parameters and methodological concerns are identified. Further, some conclusions on the environmental performance of chemicals were drawn. Results and discussion For fossil-based platform chemicals several LCAs exists but for chemicals produced with industrial biotechnology or from renewable resources the number of LCAs is limited, with the exception of biofuels, for which a large number of studies are made. In the review, a significant difference in the environmental performance of bulk and fine chemicals was identified. The environmental performance of bulk chemicals are closely connected to the production of the raw material and thereby different land use aspects. Here, a lot can be learnt from biofuel LCAs. In many of the reviewed articles focusing on bulk chemicals a comparison regarding fossil and renewable raw material was done. In most of the comparisons the renewable alternative turned out to be more environmentally preferable, especially for the impact on GWP and energy use. However, some environmental concerns were identified as important to include to assess overall environmental concern, for example eutrophication and the use of land. Conclusions To assess the environmental performance of green chemicals, quantitative methods are needed. For this purpose, both simple metrics and more comprehensive methods have been developed, one recognised method being LCA. However, this method is often too time consuming to be valuable in the process planning stage. This is partly due to a lack of available inventory data, but also because the method itself is too comprehensive. Here, key parameters for the environmental performance and methodological concerns were described to facilitate a faster and simpler use of LCA of green chemicals in the future. 相似文献
16.
Purpose The aim of this paper is to highlight the challenges that face the use of life cycle assessment (LCA) for the development of emerging technologies. LCA has great potential for driving the development of products and processes with improved environmental credentials when used at the early research stage, not only to compare novel processing with existing commercial alternatives but to help identify environmental hotspots. Its use in this way does however provide methodological and practical difficulties, often exacerbated by the speed of analysis required to enable development decisions to be made. Awareness and understanding of the difficulties in such cases is vital for all involved with the development cycle. Methods This paper employs three case studies across the diverse sectors of nanotechnology, lignocellulosic ethanol (biofuel), and novel food processes demonstrating both the synergy of issues across different sectors and highlighting the challenges when applying LCA for early research. Whilst several researchers have previously highlighted some of the issues with use of LCA techniques at an early stage, most have focused on a specific product, process development, or sector. The use of the three case studies here is specifically designed to highlight conclusively that such issues are prevalent to use of LCA in early research irrespective of the technology being assessed. Results and discussion The four focus areas for the paper are system boundaries, scaling issues, data availability, and uncertainty. Whilst some of the issues identified will be familiar to all LCA practitioners as problems shared with standard LCAs, their importance and difficulty is compounded by factors distinct to novel processes as emerging technology is often associated with unknown future applications, unknown industrial scales, and wider data gaps that contribute to the level of LCA uncertainty. These issues, in addition with others that are distinct to novel applications, such as the challenges of comparing laboratory scale data with well-established commercial processing, are exacerbated by the requirement for rapid analysis to enable development decisions to be made. Conclusions Based on the challenges and issues highlighted via illustration through the three case studies, it is clear that whilst transparency of information is paramount for standard LCAs, the sensitivities, complexities, and uncertainties surrounding LCAs for early research are critical. Full reporting and understanding of these must be established prior to utilising such data as part of the development cycle. 相似文献
17.
In view of the upcoming 2002 World Summit in Johannesburg, sustainable development is a topic of high priority in South Africa.
Although the South African competency in Life Cycle Assessment (LCA) and Life Cycle Engineering (LCE) has grown to some extent
over the last ten years, South African industry and government have been slow to realise the benefit of LCAs and LCE as tools
to support cleaner production and sustainable development. However, the local application of these tools, as well as considerations
during their use, differs from practices in developed countries. The applications of LCAs and LCE, the type of organisations
involved and the limitations and common problems associated with these tools in South Africa are discussed. 相似文献
18.
The goal of life-cycle assessment (LCA) is to conduct an inventory of the flows of materials and energy attributable to an industrial product and then to calculate the impacts of those flows on the environment, over the entire product life cycle from premanufacture to end of 1ife. A related technique, streamlined life-cycle assessment (SLCA), attempts to preserve the breadth of perspective in that approach while performing assessments more efficiently. A common failing of both techniques is that recommendations for actions to improve the environmental responsibility of products have rarely been related in an intellectually rigorous fashion to the environmental concerns they purport to ameliorate. In this article l propose that a framework for the way in which these relationships can be established is by a decision-making process that begins with the "grand objectives," the common consensus of the vital goals for the maintenance and improvement of life on Earth. The grand objectives lead to the identification of crucial environmental concerns, and those, in turn, to determining societal activities that need to be examined. Actions related to those activities can then be designed to contribute to the achievement of the grand objectives. If and when such a consensus is established, LCAs and SLCAs can be undertaken with confidence that the actions they recommend will serve broad societal goals. 相似文献
19.
Life-cycle assessment (LCA) is a new method for exploring the environmental implications of human action. Like all methods, it is analytically limited and consequently it must be used with caution. Recent papers have criticized LCA and caution against its use in all but a few narrow applications. Even while accepting many of these arguments, this article argues that LCAs, like other analytic frameworks used in the policy and planning domains, have important uses in shaping the processes by which both products and policies are designed. The arguments made against the use of LCAs omit comparisons to realistic appraisals of alternative and competing methods of environmental assessment. 相似文献
20.
Goal and Background Uncertainty is commonly not taken into account in LCA studies, which downgrades their usability for decision support. One
often stated reason is a lack of method. The aim of this paper is to develop a method for calculating the uncertainty propagation
in LCAs in a fast and reliable manner.
Approach The method is developed in a model that reflects the calculation of an LCA. For calculating the uncertainty, the model combines
approximation formulas and Monte Carlo Simulation. It is based on virtual data that distinguishes true values and random errors
or uncertainty, and that hence allows one to compare the performance of error propagation formulas and simulation results.
The model is developed for a linear chain of processes, but extensions for covering also branched and looped product systems
are made and described.
Results The paper proposes a combined use of approximation formulas and Monte Carlo simulation for calculating uncertainty in LCAs,
developed primarily for the sequential approach. During the calculation, a parameter observation controls the performance
of the approximation formulas. Quantitative threshold values are given in the paper. The combination thus transcends drawbacks
of simulation and approximation.
Conclusions and Outlook The uncertainty question is a true jigsaw puzzle for LCAs and the method presented in this paper may serve as one piece in
solving it. It may thus foster a sound use of uncertainty assessment in LCAs. Analysing a proper management of the input uncertainty,
taking into account suitable sampling and estimation techniques; using the approach for real case studies, implementing it
in LCA software for automatically applying the proposed combined uncertainty model and, on the other hand, investigating about
how people do decide, and should decide, when their decision relies on explicitly uncertain LCA outcomes-these all are neighbouring
puzzle pieces inviting to further work. 相似文献
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