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InLCA Session III B - Data Quality and Availability
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Uncertainty and Sensitivities in LCAs for Waste Management Systems

Presenter: Matthias Koller
(slides in pdf)

Matthias Koller

Universitaet Potsdam
ZfU
Park Babelsberg 14
D-14482 Potsdam
Germany
Phone: +49 (0)331 977- 4447
FAX: +49 (0)331 977 - 4433
E-mail: koller@rz.uni-potsdam.de


The paper discusses the importance and application of uncertainty analysis within LCAs by the example of LCAs for Waste Management Systems for municipal solid waste. A LCA of waste management systems has to deal with a large proportion of uncertainty as quantities and the physical and chemical composition of the systems inputs and outputs are normally not very well known and vary with time and place anyway. Also the impacts of emissions and the extension and the way separated waste fractions are reused largely depend on local and regional boundary conditions and may only be assumed.

To examine the influence of these uncertainties on the overall results the authors developed a computer aided tool which allows to investigate a wide variety of system parameters. These parameters concern the waste characterization, the process design and efficiency, the landfill behavior, the material flow management, the infrastructure and the LCA methodology.

The paper reports the results for each group of parameters and illustrates them by case specific examples. The results show that the specific contributions of the waste management don't exceed the 1% level (in Germany). The differences between the various waste management systems are small and are therefore often dominated by data and modeling uncertainties. Different evaluations methods may lead to different results too. A waste treatment system which is basically the environmental best could due to the above mentioned uncertainties not be identified. To assess the validity and the limitations of LCAs of waste management systems a sensitivity analysis investigating the uncertainties is indispensable. The results show that the analysis of uncertainty not only improves the quality of the LCA study but also offers the chance for identifying weak points and improvement opportunities of the waste management system and to elaborate the best system under case specific conditions.

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The Other Half of the Story: The Implications of System Boundary Incompleteness for LCA Inventory Data

Presenter: Tim Grant
(slides in pdf)

Dr. Graham J. Treloar, Postdoctoral Research Fellow

Australian AGILE Construction Initiative
School of Architecture and Building
Deakin University
Geelong Waterfront Campus
Geelong, 3217
Australia
Phone: +61 3 5227 8328
Mobile: +61 414 703 966
FAX: +61 3 5227 8303

Mr. Tim Grant

Centre for Design at RMIT University, Melbourne Australia
Phone: +61 3 9925 3490
Mobile: +61 408 104 977
FAX: +61 3 9639 3412
E-mail: tim.grant@rmit.edu.au


Life Cycle Assessment has many uses and applications which--in practice--involve differing levels of data quality and completeness. The traditional approach of unit process analysis is essential for identifying the life cycle stages and processes that contribute to the overall environmental impact of a product or service.

For comparative LCAs where the aim is to identify the products or options with the least environmental impact, the unit process analysis may be deficient due to incomplete system boundary definition. The LCA standard on goal and scope states " resources need not be expended on the quantification of such inputs and outputs that will not significantly change the overall conclusions of the study " (ISO 14001). It is under this assumption that many processes, such as the manufacture of capital equipment, and the provision of services and minor materials are excluded from LCAs. However, recent studies using input-output analysis, based on national economic data, indicate that a typical LCA study can be incomplete in system boundary by up to 50%. This study was based on energy related environmental loadings only. System boundary incompleteness is not consistent across all systems and products, therefore it cannot be ignored for comparative LCAs.

The use of input output analysis in LCAs is, however, limited in its resolution down at an individual process level, and also lacks the breadth of environmental data across the whole economy.

This paper examines LCA data and input-output data for a range of plastic products. It identifies some of the sources of incompleteness, and offers a solution for taking account of system boundary incompleteness through a hybrid LCA method, based on the input-output system boundary.

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Life Cycle Assessment, Data Quality and Sensitivity Analysis:
The Case of Mobile Fluid Power Systems

Presenter: Marcelle McManus

Marcelle McManus, Research Officer

Engineering Design Centre in Fluid Power Systems
Department of Mechanical Engineering
University of Bath
BA2 7AY
United Kingdom
Phone: +44 (0)1225 826826 ext 5384
FAX: +44 (0)1225 826928
E-mail: ensmcm@bath.ac.uk

G.P. Hammond, Professor of Mechanical Engineering
C.R. Burrows, Hebron and Medlock Dean of Engineering and Design

Department of Mechanical Engineering,
Faculty of Engineering and Design,
University of Bath, Claverton Down,
Bath, BA2 7AY, United Kingdom


The application of Life Cycle Assessment (LCA) has increased dramatically in the last few years. Despite the increase of awareness of LCA within the academic community and many industries, there are still problems in obtaining accurate and reliable data for many studies. Data quality and availability is therefore a major issue for the successful completion of LCA studies. Case studies often have to rely on data that are out of date or incomplete due to considerations such as commercial sensitivity. Some input parameters will have a larger impact on the final results than others, and consequently it is especially important that these data are correct and as up-to-date as possible. This paper analyses the use of sensitivity analysis in the context of life cycle impact assessment stage of LCA in order to identify the most significant input data or design parameters.

This paper builds upon a previously reported case study by the authors (1, 2) who analysed and compared the use of conventional mineral oil and biodegradable oil within a fluid power system installed on mobile forestry machinery. The operation of logging and transporting equipment in forests can have a variety of significant environmental and ecological impacts, both locally and on the wider biosphere. A sensitivity analysis has therefore been carried out for the case study and shows how sensitive the final results are to changes in the initial data and assumptions. It also illustrates how the most significant parameters can be identified and their impact minimised at the design stage. The paper outlines the complexities inherent in the use of sensitivity analysis in connection with LCA and discusses its implementation using a commercial LCA software programme to deal with such a study.

The work to be reported forms part of a major research programme funded by the UK Engineering and Physical Science Research Council to support the Engineering Design Centre in Fluid Power Systems at Bath (grant GR/L26858).

References

1. C. R. Burrows, Hammond, G.P. and McManus, M.C., Life-Cycle Assessment of Oil Hydraulic Systems for Environmentally Sensitive Applications., pp 61 - 69. in Nair, S.S. and Mistry. S.A. (eds), Fluid Power Systems and Technology, FPST (Vol. 5), ASME, Anaheim, California (ASME, 1998).

2. C. R. Burrows, Hammond, G.P. and McManus, M.C., Life Cycle Assessment of Some Mobile Hydraulic Systems., pp 1163 - 1176. in Koskinen, K.T., Vilenius, M. and Tikka, K. (eds) Proceedings: The Sixth Scandinavian International Conference on Fluid Power, SICFP '99, Tampere, Finland (1999) Tampere University of Technology (TUT) Print 1999.

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Site-dependent Life-cycle Assessment of Ozone Formation, Nutrient Enrichment and Acidification

Presenter: José Potting

José Potting

Institute of Product Development
Technical University of Denmark
Building 424
DK-2800 Lyngby
Denmark
Phone: +45-45-254677
FAX: +45-45-935556
E-mail: jp@ipt.dtu.dk

M. Hauschild

Institute of Product Development
Technical University of Denmark
Denmark

W. Schöpp

International Institute of Applied System Analysis
Austria

K. Blok

Department of Science, Technology and Society
The Netherlands


Typical life-cycle impact assessment does at present not take into account spatial variation in fate and exposure characteristics. For the impact category acidification, emissions of nitrogen or sulphur leading to depositions in areas where acidification is not at stake cause the same calculated increase in acidification as similar emissions leading to deposition in vulnerable areas. The lack of spatial differentiation may thus lead to an intolerable incorrectness in the results from life cycle impact assessment. Under the Danish Consensus Programme on Life Cycle Assessment a framework is developed to calculate spatially differentiated characterisation factors for the non-global impact categories. Impact factors have been calculated for the impact categories acidification, nutrient enrichment (atmospheric) and photochemical ozone formation. These impact factors relate the region of emission to the impact on its receiving area by integrating the dispersion of the emission and the sensitivity of the receiving environment. The factors have been established using the RAINS model. The RAINS model is an integrated assessment tool that combines information on emission sources with information on long range atmospheric transport in order to estimate patterns of deposition for comparison with critical loads or concentration levels. The resulting sets of factors cover 44 European regions, and show clear differences in impact size between sources that are located in different regions. Though the factors calculated so far are limited to the European region, the framework of a general nature and applicable to other regions (e.g. USA). The straightforward application of the site-dependent impact factors in life-cycle assessment will be illustrated for the several impact categories.

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Comparison Of Different Streamlined LCA Methods For Product Design

Presenter: M.D. Bovea

M.D. Bovea and R. Vidal

Department of Technology
Universitat Jaume I
Campus Riu Sec
12071 Castellon, Spain
Phone: + 34 964 728189
FAX: + 34 964 728106
E-mail: bovea@tec.uji.es


Increasingly, environmental performance of a product is being taken into account during its design process. The great majority of methods used to evaluate the environmental impact are based on the LCA methodology, but the collection of the amount of data needed in a full LCA is one of the most important limiting factors to the application of the methodology by the product developers. It is necessary to simplify the current LCA methodology, but without incurring the risk of obtaining different results with regard to a full LCA.

This paper proposes the study of a product family as office furniture, with the aim of obtaining the adequate design strategies to apply in future designs. In order to do this, a range of simplified or streamlined LCA techniques will be covered and their results will be compared with the ones obtained by a full LCA. Conclusions of this evaluation will show that just some streamlined techniques offer correct results and only for the product family analyzed. So, it will demonstrate how a majority of the benefits of LCA can sometimes be achieved at a fraction of the cost. The conclusions of this paper will provide to the designer a useful and reliable tool to incorporate environmental requirements into the design process.


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