Life cycle inventory data collection for First Tier suppliers - A case study of a bearing unit
Examensarbete för masterexamen
The purpose of this report is to evaluate the importance of collecting site-specific data for the First Tier suppliers in a Life Cycle Inventory (LCI) study as compared to use data from an LCI database and point out other highly polluting life-cycle stages where sitespecific data should be collected. Data collection strategies will be analysed and recommendations will be given for future Life Cycle Assessment (LCA) studies in SKF. The case study of a specific bearing has been applied. The type of the product is manufactured at one of SKF's factory. As already mentioned, this report is focused on the suppliers of SKF that provide products directly to SKF’s manufacturing facility, called First Tier suppliers. Due to time and data quality limitations, site specific data were collected only for the main local First Tier suppliers with the use of a data collection form developed specially for the purpose. These data comprise information for the raw materials and energy inputs along with waste and emissions outputs. An analysis is performed to assess the qualitative and quantitative difference of using "real" data collected from the First Tier suppliers in opposition to the LCI data of a database. For this purpose, two simplified LCI models are established by using the GaBi LCA software program. The first models site-specific data for the processes of the First Tier suppliers and the second applies LCI data offered from the GaBi’s database. Then, a thorough dominance analysis is conducted to indicate important life-cycle stages in the bearing’s production that cause major environmental impact. The interpretation of the results, in both cases, has been done by comparing the LCI results. Finally, the benefits and drawbacks of the data collection strategy are realized after a comparison to the ISO standard guidelines, other LCA studies and personal reflections. This report indicates that the two different data sources (site-specific and GaBi data), change evidently the LCI results for the total environmental load generated by the bearing’s production. These changes fluctuate up to 30 % between the two models. They are caused mainly by the quality and unavailability of inventory data in the database used. The steel production and more specifically the steel billet (used for steel bars, the raw material of rings) causes the highest environmental impact in the technical system of the analysed bearing. Regarding the data collection strategy, it proved to be quite efficient, reliable and transparent for the purpose of this study, since the most important data for the First Tier suppliers have been collected and data gaps were of minor importance to the results of the study. Future LCA studies in SKF should focus on LCI data collection for processes that influence significantly the life cycle of a product. Database data may be used cautiously for products of minor importance to the environmental performance of the investigated technical system. The data collection strategy should be based on a data questionnaire and good preparation for the site visits of the targeted companies.
Miljöteknik , Environmental engineering