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1.
The screening level LCA places itself amongst the many approaches to LCA, including full LCA and streamlined LCA. The screening level LCA combines the quantitative nature of the full LCA with the low effort of the streamlined LCA. This paper presents, as an example, a screening level LCA of the EU 2000 air handling unit from ABB Ventilation Products AB, Sweden, using the Danish EDIP impact assessment method, the EDIP software and database. This study proved that major improvement potentials can indeed be identified with screening level LCA, and argues that the screening level LCA is a suitable approach in the early stages of a company’s life cycle engineering efforts Contact for the screening level LCA method Corresponding author at ABB Corporate Research  相似文献   

2.
Life Cycle Assessment (LCA) is an analytical tool to evaluate the environmental consequences of products and their production systems. A great deal of effort has been devoted to developing methodology and guidelines for conducting LCAs. However, many companies are devising shortcuts to the full LCA model. We conducted discussions with twenty-one LCA practitioners and researchers to investigate techniques being used to simplify or streamline the LCA methodology. We found a wide variety of approaches being used to accomplish the streamlining from convening informal in-house expert panels to identify life cycle issues to developing and applying formal, structured tools.  相似文献   

3.
While life cycle assessment (LCA) is a tool often used to evaluate the environmental impacts of products and technologies, the amount of data required to perform such studies make the evaluation of emerging technologies using the conventional LCA approach challenging. The development paradox is such that the inputs from a comprehensive environmental assessment has the greatest effect early in the development phase, and yet the data required to perform such an assessment are generally lacking until it is too late. Previous attempts to formalize strategies for performing streamlined or screening LCAs were made in the late 1990s and early 2000s, mostly to rapidly compare the environmental performance of product design candidates. These strategies lack the transparency and consistency required for the environmental screening of large numbers of early‐development candidates, for which data are even sparser. We propose the Lifecycle Screening of Emerging Technologies method (LiSET). LiSET is an adaptable screening‐to‐LCA method that uses the available data to systematically and transparently evaluate the environmental performance of technologies at low readiness levels. Iterations follow technological development and allow a progression to a full LCA if desired. In early iterations, LiSET presents results in a matrix structure combined with a “traffic light” color grading system. This format inherently communicates the high uncertainty of analysis at this stage and presents numerous environmental aspects assessed. LiSET takes advantage of a decomposition analysis and data not traditionally used in LCAs to gain insight to the life cycle impacts and ensure that the most environmentally sustainable technologies are adopted.  相似文献   

4.
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   

5.
The aim of this article is to help confront uncertainty in life cycle assessments (LCAs) used for decision support. LCAs offer a quantitative approach to assess environmental effects of products, technologies, and services and are conducted by an LCA practitioner or analyst (AN) to support the decision maker (DM) in making the best possible choice for the environment. At present, some DMs do not trust the LCA to be a reliable decision‐support tool—often because DMs consider the uncertainty of an LCA to be too large. The standard evaluation of uncertainty in LCAs is an ex‐post approach that can be described as a variance simulation based on individual data points used in an LCA. This article develops and proposes a taxonomy for LCAs based on extensive research in the LCA, management, and economic literature. This taxonomy can be used ex ante to support planning and communication between an AN and DM regarding which type of LCA study to employ for the decision context at hand. This taxonomy enables the derivation of an LCA classification matrix to clearly identify and communicate the type of a given LCA. By relating the LCA classification matrix to statistical principles, we can also rank the different types of LCA on an expected inherent uncertainty scale that can be used to confront and address potential uncertainty. However, this article does not attempt to offer a quantitative approach for assessing uncertainty in LCAs used for decision support.  相似文献   

6.
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   

7.
Life cycle assessment (LCA) and environmentally extended input–output analyses (EEIOA) are two techniques commonly used to assess environmental impacts of an activity/product. Their strengths and weaknesses are complementary, and they are thus regularly combined to obtain hybrid LCAs. A number of approaches in hybrid LCA exist, which leads to different results. One of the differences is the method used to ensure that mixed LCA and EEIOA data do not overlap, which is referred to as correction for double counting. This aspect of hybrid LCA is often ignored in reports of hybrid assessments and no comprehensive study has been carried out on it. This article strives to list, compare, and analyze the different existing methods for the correction of double counting. We first harmonize the definitions of the existing correction methods and express them in a common notation, before introducing a streamlined variant. We then compare their respective assumptions and limitations. We discuss the loss of specific information regarding the studied activity/product and the loss of coherent financial representation caused by some of the correction methods. This analysis clarifies which techniques are most applicable to different tasks, from hybridizing individual LCA processes to integrating complete databases. We finally conclude by giving recommendations for future hybrid analyses.  相似文献   

8.
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   

9.
It is generally recognised that the valuation in LCA requires political, ideological and/or ethical values (hence the term). These values, however, are seldom discussed, and this paper may he seen as an early attempt. One result is that not only the valuation weighting factors, but also the choice of valuation methodology and the choice of using a valuation weighting method at all, are influenced by fundamental ethical and ideological valuations. Since there is no societal consensus on these fundamental values, and never will be one in an open democratic society, there is no reason to expect consensus either on valuation weighting factors, or on the valuation method or even on the choice of using a valuation weighting method at all. Another result of the discussion on values is that the ethical and ideological valuations are often made implicitly in the choice of method, data, etc., thus making it difficult to discuss the values and the implications of different standpoints. Although this paper focus on the valuation methods within LCA, it is expected that much of the discussion and the conclusions are of relevance for other environmental management tools, e.g. Environmental Impact Assessment.  相似文献   

10.

Purpose

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.

Methods

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.

Results and discussion

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.

Conclusions

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.
  相似文献   

11.
The use of different input data, functional units, allocation methods, reference systems and other assumptions complicates comparisons of LCA bioenergy studies. In addition, uncertainties and use of specific local factors for indirect effects (like land-use change and N-based soil emissions) may give rise to wide ranges of final results. In order to investigate how these key issues have been addressed so far, this work performs a review of the recent bioenergy LCA literature. The abundance of studies dealing with the different biomass resources, conversion technologies, products and environmental impact categories is summarized and discussed. Afterwards, a qualitative interpretation of the LCA results is depicted, focusing on energy balance, GHG balance and other impact categories. With the exception of a few studies, most LCAs found a significant net reduction in GHG emissions and fossil energy consumption when bioenergy replaces fossil energy.  相似文献   

12.
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   

13.
Purpose

Due 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.

Methods

The 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 discussion

While 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.

Conclusions

Overall, 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   

14.
LCA of soybean meal   总被引:2,自引:0,他引:2  
Background, Aim and Scope  Soybean meal is an important protein input to the European livestock production, with Argentina being an important supplier. The area cultivated with soybeans is still increasing globally, and so are the number of LCAs where the production of soybean meal forms part of the product chain. In recent years there has been increasing focus on how soybean production affects the environment. The purpose of the study was to estimate the environmental consequences of soybean meal consumption using a consequential LCA approach. The functional unit is ‘one kg of soybean meal produced in Argentina and delivered to Rotterdam Harbor’. Materials and Methods  Soybean meal has the co-product soybean oil. In this study, the consequential LCA method was applied, and co-product allocation was thereby avoided through system expansion. In this context, system expansion implies that the inputs and outputs are entirely ascribed to soybean meal, and the product system is subsequently expanded to include the avoided production of palm oil. Presently, the marginal vegetable oil on the world market is palm oil but, to be prepared for fluctuations in market demands, an alternative product system with rapeseed oil as the marginal vegetable oil has been established. EDIP97 (updated version 2.3) was used for LCIA and the following impact categories were included: Global warming, eutrophication, acidification, ozone depletion and photochemical smog. Results  Two soybean loops were established to demonstrate how an increased demand for soybean meal affects the palm oil and rapeseed oil production, respectively. The characterized results from LCA on soybean meal (with palm oil as marginal oil) were 721 gCO2 eq. for global warming potential, 0.3 mg CFC11 eq. for ozone depletion potential, 3.1 g SO2 eq. for acidification potential, −2 g NO3 eq. for eutrophication potential and 0.4 g ethene eq. for photochemical smog potential per kg soybean meal. The average area per kg soybean meal consumed was 3.6 m2year. Attributional results, calculated by economic and mass allocation, are also presented. Normalised results show that the most dominating impact categories were: global warming, eutrophication and acidification. The ‘hot spot’ in relation to global warming, was ‘soybean cultivation’, dominated by N2O emissions from degradation of crop residues (e.g., straw) and during biological nitrogen fixation. In relation to eutrophication and acidification, the transport of soybeans by truck is important, and sensitivity analyses showed that the acidification potential is very sensitive to the increased transport distance by truck. Discussion  The potential environmental impacts (except photochemical smog) were lower when using rapeseed oil as the marginal vegetable oil, because the avoided production of rapeseed contributes more negatively compared with the avoided production of palm oil. Identification of the marginal vegetable oil (palm oil or rapeseed oil) turned out to be important for the result, and this shows how crucial it is in consequential LCA to identify the right marginal product system (e.g., marginal vegetable oil). Conclusions  Consequential LCAs were successfully performed on soybean meal and LCA data on soybean meal are now available for consequential (or attributional) LCAs on livestock products. The study clearly shows that consequential LCAs are quite easy to handle, even though it has been necessary to include production of palm oil, rapeseed and spring barley, as these production systems are affected by the soybean oil co-product. Recommendations and Perspectives  We would appreciate it if the International Journal of Life Cycle Assessment had articles on the developments on, for example, marginal protein, marginal vegetable oil, marginal electricity (related to relevant markets), marginal heat, marginal cereals and, likewise, on metals and other basic commodities. This will not only facilitate the work with consequential LCAs, but will also increase the quality of LCAs.  相似文献   

15.
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   

16.
Goal, Scope and Background  Two methods of simplified LCA were evaluated and compared to the results of a quantitative LCA. These are the Environmentally responsible product assessment matrix developed by Graedel and Allenby and the MECO-method developed in Denmark. Methods  We used these in a case study and compared the results with the results from a quantitative LCA. The evaluation also included other criteria, such as the field of application and the level of arbitrariness. Results and Discussion  The MECO-method has some positive qualities compared to the Environmentally responsible product assessment matrix. Examples of this are that it generates information complementary to the quantitative LCA and provides the possibility to consider quantitative information when such is available. Some of the drawbacks with the Environmentally responsible product assessment matrix are that it does not include the whole lifecycle and that it allows some arbitrariness. Conclusions  Our study shows that a simplified and semi-quantitative LCA (such as the MECO-method) can provide information that is complementary to a quantitative LCA. In this case the method generates more information on toxic substances and other impacts, than the quantitative LCA. We suggest that a simplified LCA can be used both as a pre-study to a quantitative LCA and as a parallel assessment, which is used together with the quantitative LCA in the interpretation. Recommendations and Outlook  A general problem with qualitative analyses is how to compare different aspects. Life cycle assessments are comparative. The lack of a quantitative dimension hinders the comparison and can thereby hinder the usefulness of the qualitative method. There are different approaches suggested to semiquantify simplified methods in order to make quantitative comparisons possible. We think that the use of fabricated scoring systems should be avoided. If quantitative information is needed, one should consider performing a simplified quantitative LCA instead.  相似文献   

17.
Life cycle assessment (LCA) is a quantitative tool used to evaluate the environmental impacts of products or processes. With respect to buildings, LCA can be used to evaluate the environmental impacts of an entire building's life cycle. Currently LCA in the building area is used in a limited capacity, primarily to select building products. In order to determine the causality for the lack of whole‐building LCAs, focus groups with members of the architecture, engineering, and construction (AEC) communities were held. This article investigates the current level of knowledge of LCA in the AEC community and then discusses the benefits and barriers to the practice of LCA. In summary, the goal of the research was to identify why LCA is not used to its fullest potential in a whole‐building LCA. In an open forum and moderated setting, focus group participants were asked individually to self‐identify their experience with LCA, a brief education session on LCA was held, and then benefits and barriers to LCA were discussed. The focus group sessions were transcribed and systematically coded by social researchers in order to analyze the results. Hybrid flow and radar charts were developed. From the focus group results, the most important benefit to LCA was “provides information about environmental impacts.” The results did not identify a prominent barrier; however, building‐related metrics were ascertained to be one of the more crucial barriers. The benefits and barriers classified by this analysis will be utilized to develop a subsequent online survey to further understand the LCA and AEC community.  相似文献   

18.
Goal, Scope and Background In face of continued declines in global fisheries landings and concurrent rapid aquaculture development, the sustainability of seafood production is of increasing concern. Life Cycle Assessment (LCA) offers a convenient means of quantifying the impacts associated with many of the energetic and material inputs and outputs in these industries. However, the relevant but limited suite of impact categories currently used in most LCA research fails to capture a number of important environmental and social burdens unique to fisheries and aquaculture. This article reviews the impact categories used in published LCA research of seafood production to date, reports on a number of methodological innovations, and discusses the challenges to and opportunities for further impact category developments. Main Features The range of environmental and socio-economic impacts associated with fisheries and aquaculture production are introduced, and both the commonly used and innovative impact categories employed in published LCA research of seafood production are discussed. Methodological innovations reported in agricultural LCAs are also reviewed for possible applications to seafood LCA research. Challenges and options for including additional environmental and socioeconomic impact categories are explored. Results A review of published LCA research in fisheries and aquaculture indicates the frequent use of traditional environmental impact categories as well as a number of interesting departures from the standard suite of categories employed in LCA studies in other sectors. Notable examples include the modeling of benthic impacts, by-catch, emissions from anti-fouling paints, and the use of Net Primary Productivity appropriation to characterize biotic resource use. Socio-economic impacts have not been quantified, nor does a generally accepted methodology for their consideration exist. However, a number of potential frameworks for the integration of such impacts into LCA have been proposed. Discussion LCA analyses of fisheries and aquaculture call attention to an important range of environmental interactions that are usually not considered in discussions of sustainability in the seafood sector. These include energy use, biotic resource use, and the toxicity of anti-fouling paints. However, certain important impacts are also currently overlooked in such research. While prospects clearly exist for improving and expanding on recent additions to environmental impact categories, the nature of the LCA framework may preclude treatment of some of these impacts. Socio-economic impact categories have only been described in a qualitative manner. Despite a number of challenges, significant opportunities exist to quantify several important socio-economic impacts. Conclusion The limited but increasing volume of LCA research of industrial fisheries and aquaculture indicates a growing interest in the use of LCA methodology to understand and improve the sustainability performance of seafood production systems. Recent impact category innovations, and the potential for further impact category developments that account for several of the unique interactions characteristic of fisheries and aquaculture will significantly improve the usefulness of LCA in this context, although quantitative analysis of certain types of impacts may remain beyond the scope of the LCA framework. The desirability of incorporating socio-economic impacts is clear, but such integration will require considerable methodological development. Recommendations and Perspectives While the quantity of published LCA research for seafood production systems is clearly increasing, the influence this research will have on the ground remains to be seen. In part, this will depend on the ability of LCA researchers to advance methodological innovations that enable consideration of a broader range of impacts specific to seafood production. It will also depend on the ability of researchers to communicate with a broader audience than the currently narrow LCA community.  相似文献   

19.
Goal, Scope and Background  Assessing future energy and transport systems is of major importance for providing timely information for decision makers. In the discussion of technology options, fuel cells are often portrayed as attractive options for power plants and automotive applications. However, when analysing these systems, the LCA analyst is confronted with methodological problems, particularly with data gaps and the requirement of an anticipation of future developments. This series of two papers aims at providing a methodological framework for assessing future energy and transport systems (Part 1) and applies this to the two major application areas of fuel cells (Part 2). Methods  To allow the LCA of future energy and transport systems forecasting tools like, amongst others, cost estimation methods and process simulation of systems are investigated with respect to the applicability in LCAs of future systems (Part 1). The manufacturing process of an SOFC stack is used as an illustration for the forecasting procedure. In Part 2, detailed LCAs of fuel cell power plants and power trains are carried out including fuel (hydrogen, methanol, gasoline, diesel and natural gas) and energy converter production. To compare it with competing technologies, internal combustion engines (automotive applications) and reciprocating engines, gas turbines and combined cycle plants (stationary applications) are analysed as well. Results and Discussion  Principally, the investigated forecasting methods are suitable for future energy system assessment. The selection of the best method depends on different factors such as required ressources, quality of the results and flexibility. In particular, the time horizon of the investigation determines which forecasting tool may be applied. Environmentally relevant process steps exhibiting a significant time dependency shall always be investigated using different independent forecasting tools to ensure stability of the results. The results of the LCA (Part 2) underline that principally, fuel cells offer advantages in the impact categories which are typically dominated by pollutant emissions, such as acidification and eutrophication, whereas for global warming and primary energy demand, the situation depends on a set of parameters such as driving cycle and fuel economy ratio in mobile applica-tions and thermal/total efficiencies in stationary applications. For the latter impact categories, the choice of the primary en-ergy carrier for fuel production (renewable or fossil) dominates the impact reduction. With increasing efficiency and improving emission performance of the conventional systems, the competition regarding all impact categories in both mobile and stationary applications is getting even stronger. The production of the fuel cell system is of low overall significance in stationary applications, whereas in automotive applications, the production of the fuel cell power train and required materials leads to increased impacts compared to internal combustion engines and thus reduces the achievable environmental impact reduction. Recommendations and Perspectives  The rapid technological and energy economic development will bring further advances for both fuel cells and conventional energy converters. Therefore, LCAs at such an early stage of the market development can only be considered preliminary. It is an essential requirement to accompany the ongoing research and development with iterative LCAs, constantly pointing at environmental hot spots and bottlenecks.  相似文献   

20.

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   

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