Jeroen B. Guinée

Handbook on life cycle assessment operational guide to the ISO standards

Preface. Foreword. Part 1: LCA in Perspective. 1. Why a new Guide to LCA? 2. Main characteristics of LCA. 3. International developments. 4. Guiding principles for the present Guide. 5. Reading guide. Part 2a: Guide. Reading guidance. 1. Management of LCA projects: procedures. 2. Goal and scope definition. 3. Inventory analysis. 4. Impact assessment. 5. Interpretation. Appendix A: Terms, definitions and abbreviations. Part 2b: Operational annex. List of tables. Reading guidance. 1. Management of LCA projects: procedures. 2. Goal and scope definition. 3. Inventory analysis. 4. Impact assessment. 5. Interpretation. 6. References. Part 3: Scientific background. Reading guidance. 1. General introduction. 2. Goal and scope definition. 3. Inventory analysis. 4. Impact assessment. 5. Interpretation. 6. References. Annex A: Contributors. Appendix B: Areas of application of LCA. Appendix C: Partitioning economic inputs and outputs to product systems.

Recent developments in Life Cycle Assessment.

Life Cycle Assessment is a tool to assess the environmental impacts and resources used throughout a products life cycle, i.e., from raw material acquisition, via production and use phases, to waste management. The methodological development in LCA has been strong, and LCA is broadly applied in practice. The aim of this paper is to provide a review of recent developments of LCA methods. The focus is on some areas where there has been an intense methodological development during the last years. We also highlight some of the emerging issues. In relation to the Goal and Scope definition we especially discuss the distinction between attributional and consequential LCA. For the Inventory Analysis, this distinction is relevant when discussing system boundaries, data collection, and allocation. Also highlighted are developments concerning databases and Input-Output and hybrid LCA. In the sections on Life Cycle Impact Assessment we discuss the characteristics of the modelling as well as some recent developments for specific impact categories and weighting. In relation to the Interpretation the focus is on uncertainty analysis. Finally, we discuss recent developments in relation to some of the strengths and weaknesses of LCA.

Life Cycle Assessment: Past, Present, and Future†

Environmental life cycle assessment (LCA) has developed fast over the last three decades. Whereas LCA developed from merely energy analysis to a comprehensive environmental burden analysis in the 1970s, full-fledged life cycle impact assessment and life cycle costing models were introduced in the 1980s and 1990 s, and social-LCA and particularly consequential LCA gained ground in the first decade of the 21st century. Many of the more recent developments were initiated to broaden traditional environmental LCA to a more comprehensive Life Cycle Sustainability Analysis (LCSA). Recently, a framework for LCSA was suggested linking life cycle sustainability questions to knowledge needed for addressing them, identifying available knowledge and related models, knowledge gaps, and defining research programs to fill these gaps. LCA is evolving into LCSA, which is a transdisciplinary integration framework of models rather than a model in itself. LCSA works with a plethora of disciplinary models and guides selecting the proper ones, given a specific sustainability question. Structuring, selecting, and making the plethora of disciplinary models practically available in relation to different types of life cycle sustainability questions is the main challenge.

Identifying best existing practice for characterization modeling in life cycle impact assessment

PurposeLife cycle impact assessment (LCIA) is a field of active development. The last decade has seen prolific publication of new impact assessment methods covering many different impact categories and providing characterization factors that often deviate from each other for the same substance and impact. The LCA standard ISO 14044 is rather general and unspecific in its requirements and offers little help to the LCA practitioner who needs to make a choice. With the aim to identify the best among existing characterization models and provide recommendations to the LCA practitioner, a study was performed for the Joint Research Centre of the European Commission (JRC).MethodsExisting LCIA methods were collected and their individual characterization models identified at both midpoint and endpoint levels and supplemented with other environmental models of potential use for LCIA. No new developments of characterization models or factors were done in the project. From a total of 156 models, 91 were short listed as possible candidates for a recommendation within their impact category. Criteria were developed for analyzing the models within each impact category. The criteria addressed both scientific qualities and stakeholder acceptance. The criteria were reviewed by external experts and stakeholders and applied in a comprehensive analysis of the short-listed characterization models (the total number of criteria varied between 35 and 50 per impact category). For each impact category, the analysis concluded with identification of the best among the existing characterization models. If the identified model was of sufficient quality, it was recommended by the JRC. Analysis and recommendation process involved hearing of both scientific experts and stakeholders.Results and recommendationsRecommendations were developed for 14 impact categories at midpoint level, and among these recommendations, three were classified as “satisfactory” while ten were “in need of some improvements” and one was so weak that it has “to be applied with caution.” For some of the impact categories, the classification of the recommended model varied with the type of substance. At endpoint level, recommendations were only found relevant for three impact categories. For the rest, the quality of the existing methods was too weak, and the methods that came out best in the analysis were classified as “interim,” i.e., not recommended by the JRC but suitable to provide an initial basis for further development.Discussion, conclusions, and outlookThe level of characterization modeling at midpoint level has improved considerably over the last decade and now also considers important aspects like geographical differentiation and combination of midpoint and endpoint characterization, although the latter is in clear need for further development. With the realization of the potential importance of geographical differentiation comes the need for characterization models that are able to produce characterization factors that are representative for different continents and still support aggregation of impact scores over the whole life cycle. For the impact categories human toxicity and ecotoxicity, we are now able to recommend a model, but the number of chemical substances in common use is so high that there is a need to address the substance data shortage and calculate characterization factors for many new substances. Another unresolved issue is the need for quantitative information about the uncertainties that accompany the characterization factors. This is still only adequately addressed for one or two impact categories at midpoint, and this should be a focus point in future research. The dynamic character of LCIA research means that what is best practice will change quickly in time. The characterization methods presented in this paper represent what was best practice in 2008–2009.

Priority assessment of toxic substances in life cycle assessment. Part I: Calculation of toxicity potentials for 181 substances with the nested multi-media fate, exposure and effects model USES-LCA

Toxicity potentials are standard values used in life cycle assessment (LCA) to enable a comparison of toxic impacts between substances. In most cases, toxicity potentials are calculated with multi-media fate models. Until now, unrealistic system settings were used for these calculations. The present paper outlines an improved model to calculate toxicity potentials: the global nested multi-media fate, exposure and effects model USES-LCA. It is based on the Uniform System for the Evaluation of Substances 2.0 (USES 2.0). USES-LCA was used to calculate for 181 substances toxicity potentials for the six impact categories freshwater aquatic ecotoxicity, marine aquatic ecotoxicity, freshwater sediment ecotoxicity, marine sediment ecotoxicity, terrestrial ecotoxicity and human toxicity, after initial emission to the compartments air, freshwater, seawater, industrial soil and agricultural soil, respectively. Differences of several orders of magnitude were found between the new toxicity potentials and those calculated previously.

Quantitative life cycle assessment of products: 1:Goal definition and inventory

Abstract Quantitative environmental life cycle assessment of products can be a useful tool in product-oriented environmental management. With this methodology the environmental impacts of the product during its entire life cycle are attributed quantitatively to the functioning of the product as far as possible. Currently, the scientific basis of methods for assessing the environmental impacts of products is not yet adequate. Methods are divergent, yield conflicting results and contain considerable gaps. In two successive articles an overview of the similarities and differences between these methods, as developed in different countries, is given. To enable fruitful discussions on methods used, and to make life cycle assessment (LCA) an acceptable tool for product-oriented environmental management, a general methodological framework is proposed. In this first article a general introduction to LCA is given, a general methodological framework is proposed and two components of the methodological framework, the goal definition and the inventory, are discussed in more detail.

Economic Allocation : Examples and Derived Decision Tree

Goal, Scope and BackgroundIn the recently published (Dutch) Handbook on LCA, economic allocation is advised as baseline method for most allocation situations in a detailed LCA. Although the Handbook on LCA aimed to provide a ‘cookbook’ with operational guidelines for conducting each step of an LCA, this was not completely achieved for the allocation step. The guidelines for allocation largely remained at the level of principles. This restricted elaboration of economic allocation may hamper application in practice. Therefore, this paper elaborates some examples applying economic allocation.MethodTwo concepts are of particular importance when applying economic allocation: functional flow and multi-functional process. The definitions of these concepts are presented and discussed. The basic principle of economic allocation is that having determined the various functional flows of a multi-functional process, all other flows need to be allocated to these functional flows according to their shares in the total proceeds. Proceeds are based on prices and these are not always easy to determine for a process. A summary of possible solutions for different problems when determining prices is given.Results and DiscussionThe examples presented focus on co-production and various recycling situations. All examples are hypothetical in order to avoid discussions on the data. The examples show that the prices of the functional flows determine the allocation results. It is of importance to have correct information on the relative prices of the functional flows at stake, especially whether they are negative or positive. Learning from these examples, we establish a decision tree for economic allocation. The decision tree is meant for identifying and handling multi-functionality situations starting from a defined (product) system. This decision tree is with minor adaptations also applicable to other allocation methods and has a more general value than for the economic allocation method only.Conclusions and perspectiveThe examples have helped us to establish a decision tree for handling the multi-functionality problem by economic allocation. The examples can be broadened to other materials and allocation situations. We would encourage others to provide other examples and experiences as we expect that these will help to further improve and refine the guidelines and decision tree for economic allocation in future.

A proposal for the classification of toxic substances within the framework of life cycle assessment of products

Quantitative life cycle assessment (lca) is a method allocating the environmental impacts of the whole life cycle of a product to the functioning of that product. The scientific basis of the method is still being elaborated. In this paper a proposal is made to improve the scientific basis of one specific step of the methods: the aggregation of potentially toxic emissions of substances in one score for human toxicity and two scores for ecotoxicity. The aggregation is based on multimedia environmental models of Mackay simulating the behaviour of substances in the environment, and on toxicity data such as acceptable resp. tolerable daily intake (adi resp. tdi) and no observed effect concentration (noec) per substance. It is proposed to apply models describing the environmental fate of toxic substances in lcas of products. In addition, it is proposed to adopt the concept of a reference substance, as used in the ozone depletion potential (odp) and the global warming potential (gwp), to assess and aggregate emissions of potentially toxic substances.

Quantitative life cycle assessment of products. 2. Classification, valuation and improvement analysis

In a previous article about life cycle assessment (LCA), a methodological framework was proposed and two components of this framework were discussed in more detail: the goal definition and the inventory. In this second article, the other components of the framework are discussed in detail: the classification, the valuation and the improvement analysis. In the classification, resource extractions and emissions associated with the life cycle of a product are translated into contributions to a number of environmental problem types, such as resource depletion, global warming, ozone depletion, acidification, etc. For this, each extraction and emission is multiplied with a so-called classification factor and the multiplication results are aggregated per problem type. Classification factors are proposed for a number of environmental problem types. The valuation includes both a valuation of the different environmental problem types and an assessment of the reliability and validity of the results. For the valuation of the environmental problem types, qualitative or quantitative multicriterion analysis could be applied. Given a standard list of weighting factors the quantitative multicriterion analysis seems preferable, because of its low costs and its simplicity. The main problem, however, is to get a broadly supported standard list. In studies so far little attention is paid to the assessment of the reliability and the validity of the results. To improve this situation methods which could support this assessment are proposed. In the improvement analysis potential options to improve the product(s) studied are identified. Combined with expertise in other fields, such as costs and technological feasibility, the improvement analysis may yield a number of serious options for the redesign of a product. Two complementary techniques for the identification of the potential options are discussed. With these techniques and the active participation of process technologists and designers, LCA might become an analytic tool for eco-design supporting a continuous environmental improvement of products.

Evaluation of risks of metal flows and accumulation in economy and environment

The contrast between, on the one hand, decreasing emissions of the metals cadmium, copper, lead and zinc and, on the other, their continuously increasing input into the economy is analysed for three case studies: The Netherlands as a whole, the Dutch housing sector and the Dutch agricultural sector. Flows of these metals through and their accumulation within the economy and the environment have been quantified for 1990 and for a constructed steady-state situation. To this end, the substance flow analysis method has been applied. The case studies show that there is a strong increase to be expected in the emissions from the 1990 to the steady-state situation. This increase is mainly due to the shift from landfill accumulation to emission to non-agricultural soil. At the same time, however, there is also an increase in the emissions to other media: air, water and agricultural soil. Emissions along these critical routes with respect to human and ecotoxicity show an approximately 30% increase for cadmium, lead and zinc and more than a doubling for copper. It is shown that this increase may lead to the surpassing of critical levels for human toxicity and terrestrial and aquatic ecotoxicity. Some possible measures are suggested to prevent critical levels being exceeded.