Life cycle assessment of tractors

This study was intended to evaluate the environmental impact, and potential improvements for a typical tractor model (LT360D) of LG Machinery Co., Ltd. The life cycle of this study includes all stages from raw material acquisition up to final disposal. The eco-indicator 95 method was employed to perform an impact assessment. The result of this study is expected to represent the environmental feature of typical diesel vehicles at each life cycle stage. This study is a starting point of building life cycle inventories for typical off-road diesel tractors. With this result, environmental weak points of the tractor have been defined, and major improvement strategies have been set up to develop the ‘Green Tractor’.     

Using GaBi 3 to perform life cycle assessment and life cycle engineering

The growing availability of software tools has increased the speed of generating LCA studies. Databases and visual tools for constructing material balance modules greatly facilitate the process of analyzing the environmental aspects of product systems over their life cycle. A robust software tool, containing a large LCI dataset and functions for performing LCIA and sensitivity analysis will allow companies and LCA practitioners to conduct systems analyses efficiently and reliably. This paper discusses how the GaBi 3 software tool can be used to perform LCA and Life Cycle Engineering (LCE), a methodology that combines life cycle economic, environmental, and technology assessment. The paper highlights important attributes of LCA software tools, including high quality, well-documented data, transparency in modeling, and data analysis functionality. An example of a regional power grid mix model is used to illustrate the versatility of GaBi 3.     

Environmental life cycle assessment of linoleum

Linoleum is a floor covering consisting mainly of linseed oil, other vegetable oils, wood flour and limestone on a carrier of jute. Forbo-Krommenie B.V. commissioned the Centre of Environmental Science (CML) to carry out an Environmental Life Cycle Assessment for linoleum floors. The goal of this study was to assess the environmental performance of linoleum floors, indicating possible options for improvement, and assessing the sensitivity of the results to methodological choices. The functional unit was defined as: 2000 m² linoleum produced in 1998, used in an office or public building over a period of 20 years. The method followed in this study is based on a nearly final draft version of the LCA guide published by CML in corporation with many others, which is an update of the guide on LCA of 1992. From the contribution analysis, the main contributing processes became clear. In addition, the sensitivity analysis by scenarios showed that the type of maintenance during use and the pigments used can have a large influence on the results. Major data gaps of the study were capital goods and unknown chemicals. Sensitivity analysis also showed that these gaps can lead to an underestimation. Based on this study, some options to improve the environmental performance of linoleum were formulated and advice for further LCA studies on linoleum was given.     

Influence of functional unit on the life cycle assessment of traction batteries

Goal, Scope and Background This paper describes the influence of the choice of the functional unit on the results of an environmental assessment of different battery technologies for electric and hybrid vehicles. Battery, hybrid and fuel cell electric vehicles are considered as being environmentally friendly. However, the batteries they use are sometimes said to be environmentally unfriendly. At the current state of technology different battery types can be envisaged: lead-acid, nickel-cadmium, nickel-metal hydride, lithium-ion and sodium-nickel chloride. The environmental impacts described in this paper are based on a life cycle assessment (LCA) approach. One of the first critical stages of LCA is the definition of an appropriate and specific functional unit for electric and hybrid vehicle application. Most of the known LCA studies concerning batteries were performed while choosing different functional units, although this choice can influence the final results. An adequate functional unit, allowing to compare battery technologies in their real life vehicle application should be chosen. The results of the LCA are important as they will be used as a decision support for the end-of-life vehicles directive 2000/53/EC (Official Journal of the European Communities L269/24 2000). As a consequence, a thorough analysis is required to define an appropriate functional unit for the assessment of batteries for electric vehicles. This paper discusses this issue and will mainly focus on traction batteries for electric vehicles. Main Features An overview of the different parameters to be considered in the definition of a functional unit to compare battery technologies for battery electric vehicle application is described and discussed. An LCA study is performed for the most relevant potential functional units. SimaPro 6 is used as a software tool and Eco-indicator 99 as an impact assessment method. The influence of the different selected functional units on the results (Eco-indicator Points) is discussed. The environmental impact of the different electric vehicle battery technologies is described. A sensitivity analysis illustrates the robustness of the obtained results. Results and Discussion Five main parameters are considered in each investigated functional unit: an equal depth of discharge is assumed, a relative number of batteries required during the life of the vehicle is calculated, the energy losses in the battery and the additional vehicle consumption due to the battery mass is included and the same lifetime distance target is taken into account. On the basis of the energy content, battery mass, number of cycles and vehicle autonomy three suitable functional units are defined: ‘battery packs with an identical mass’, ‘battery packs with an identical energy content’ and ‘battery packs with an identical one-charge range’. The results show that the differences in the results between these three functional units are small and imply less variation on the results than the other uncertainties inherent to LCA studies. On the other hand, the results obtained using other, less adequate, functional units can be quite different. Conclusions When performing an LCA study, it’s important to choose an appropriate functional unit. Most of the time, this choice is unambiguous. However, sometimes this choice is more complicated when different correlated parameters have to be considered, as it is the case for traction batteries. When using a realistic functional unit, the result is not influenced significantly by the choice of one out of the three suitable functional units. Additionally, the life cycle assessment allowed concluding that three electric vehicle battery technologies have a comparable environmental impact: lead-acid, nickel-cadmium and nickel-metal hydride. Lithium-ion and sodium-nickel chloride have lower environmental impacts than the three previously cited technologies when used in a typical battery electric vehicle application. Recommendations and Perspectives The article describes the need to consider all relevant parameters for the choice of a functional unit for an electric vehicle battery, as this choice can influence the conclusions. A more standardised method to define the functional unit could avoid these differences and could make it possible to compare the results of different traction battery LCA studies more easily.     

A semi-quantitative method for the impact assessment of emissions within a simplified life cycle assessment

Intention, Goal and Scope: Dealing with data gaps, data asymmetries, and inconsistencies in life cycle inventories (LCI) is a general prohlem in Life Cycle Assessment (LCA) studies. An approach to deal with these difficulties is the simplification of LCA. A methodology that lowers the requirements for data quality (accuracy) for process emissions within a simplified LCA is introduced in this article. Background: Simplification is essential for applying LCA in the context of design for environment (DfE). The tool euroMat is a comprehensive DfE software tool that is based on a specific, simplified LCA approach, the Iterative Screening LCA (IS-LCA). Within the scope of the IS-LCA, there is a quantitative assessment of energy-related processes, as well as a semi-quantitative assessment of non-energy related emissions which supplement each other. Objectives: The semi-quantitative assessment, which is in the focus of this article, aims at lowering the requirements for the quality of non-energy related emissions data through combined use of qualitative and quantitative inventory data. Methods: Potential environmental impacts are assessed based on ABC-categories for qualities (harmfulness) of emissions and XYZ-categories for quantities of emitted substances. Employing statistical methods assignment rules for the ABC/XYZ-categories were derived from literature data and databases on emissions to air, water, and soil. Statistical tests as well as a DfE case study (comparing the materials aluminum and carbon fiber reinforced epoxy for a lightweight container to be used in an aerospace application) were conducted in order to evaluate the level of confidence and practicality of the proposed, simplified impact assessment. Results: Statistical and technical consistency checks show that the method bears a high level of confidence. Results obtained by the simplified assessment correlate to those of a detailed quantitative LCA. Conclusions: Therefore, the application of the ABC/XYZ-categories (together with the cumulative energy demand) can be considered a practical and consistent approach for determining the environmental significance of products when only incomplete emission data is available. Future Prospects: The statistical base of the method is expanded continuously since it is an integral part of the DfE software tool euroMat, which is currently being further developed. That should foster the application of the method. Outside DfE, the method should also be capable of facilitating simplified LCAs in general.     

Life cycle assessment of municipal waste water systems

Life Cycle Assessment was applied to municipal planning in a study of waste water systems in Bergsjön, a Göteborg suburb, and Hamburgsund, a coastal village. Existing waste water treatment consists of mechanical, biological and chemical treatment. The heat in the waste water from Bergsjön is recovered for the district heating system. One alternative studied encompassed pretreatment, anaerobic digestion or drying of the solid fraction and treatment of the liquid fraction in sand filter beds. In another alternative, urine, faeces and grey water would separately be conducted out of the buildings. The urine would be used as fertilizer, whereas faeces would be digested or dried, before used in agriculture. The grey water would be treated in filter beds. Changes in the waste water system would affect surrounding technical systems (drinking water production, district heating and fertilizer production). This was approached through system enlargement. For Hamburgsund, both alternatives showed lower environmental impact than the existing system, and the urine separation system the lowest. Bergsjön results were more difficult to interpret. Energy consumption was lowest for the existing system, whereas air emissions were lower for the alternatives. Water emissions increased for some parameters and decreased for others. Phosphorous recovery was high for all three alternatives, whereas there was virtually no nitrogen recovery until urine separation was introduced.     

Life cycle assessment of the selective catalytic reduction process for power plants

The overall reduction of the environmental impact by the use of selective catalytic reduction (SCR) of nitrogen oxide emissions in power plants was determined by strict application of ISO 14040 and ISO/DIS 14041. Special emphasis was placed on the implementation of the total product life cycle (PLC) of ammonium molybdate as a key input material. The environmental impact was generated by application of the life cycle assessment (LCA) concept of “ecoscarcity” and integrated in the life cycle inventory analysis (LCI) of SCR systems. The LCI was used to generate the life cycle impact assessment (LC1A) by use of different quantitative valuation methods. Under consideration of the overall LCIA results and the environmental protection costs of the SCR variants, the Ecological Effectiveness of the SCR alternatives was determined. The results enable plausible conclusions with regard to the ecological advantages of the use of deNOx catalysts in the SCR used in hard-coal fired power plants.     

Survey of approaches to improve reliability in lca

Limitations of data quality and difficulties to assess uncertainty are long since acknowledged problems in LCA. During recent years a range of tools for improvement of reliability in LCA have been presented, but despite this there is still a lack of consensus about how these issues should be handled. To give basic understanding of data quality and uncertainty in LCA, key concepts of data quality and uncertainty in the context of LCA are explained. A comprehensive survey of methods and approaches for data quality management, sensitivity analysis, and uncertainty analysis published in the LCA literature is presented. It should serve as a guide to further reading for LCA practitioners interested in improving data quality management and uncertainty assessment in LCA projects. The suitability of different tools for addressing different types of uncertainty and future needs in this field is discussed.     

On the limitations of life cycle assessment and environmental systems analysis tools in general

The potential and limitations of life cycle assessment and environmental systems analysis tools in general are evaluated. More specifically this is done by exploring the limits of what can be shown by LCA and other tools. This is done from several perspectives. First, experiences from current LCAs and methodology discussions are used including a discussion on the type of impacts typically included, quality of inventory data, methodological choices in relation to time aspects, allocation, characterisation and weighting methods and uncertainties in describing the real world. Second, conclusions from the theory of science are practised. It is concluded that it can in general not be shown that one product is environmentally preferable to another one, even if this happens to be the case. This conclusion has important policy implications. If policy changes require that it must be shown that one product is more (or less) environmentally preferable before any action can be taken, then it is likely that no action is ever going to take place. If we want changes to be made, decisions must be taken on a less rigid basis. It is expected that in this decision making process, LCA can be a useful input. Since it is the only tool that can be used for product comparisons over the whole life cycle, it can not be replaced by any other tool and should be used. Increased harmonisation of LCA methodology may increase the acceptability of chosen methods and increase the usefulness of the tool.