Life cycle approach to sustainability assessment: a case study of remanufactured alternators

Erwin M. Schau 0 Marzia Traverso 0 Matthias Finkbeiner 0 0 Department of Environmental Technology, Chair of Sustainable Engineering, Technische Universitaet Berlin , Office Z1, Strasse des 17. Juni 135, Berlin D-10623, Germany Sustainability is an international issue with increasing concern and becomes a crucial driver for the industry in international competition. Sustainability encompasses the three dimensions: environment, society and economy. This paper presents the results from a sustainability assessment of a product. To prevent burden shifting, the whole life cycle of the products is necessary to be taken into account. For the environmental dimension, life cycle assessment (LCA) has been practiced for nearly 40 years and is the only one standardised by the International Organization for Standardization (ISO) (14040 and 14044). Life cycle approaches for the social and economic dimensions are currently under development. Life cycle sustainability assessment (LCSA) is a complementary implementation of the three techniques: LCA (environmental), life cycle costing (LCC - economic) and social LCA (SLCA - social). This contribution applies the state-of-the-art LCSA on remanufacturing of alternators aiming at supporting managers and product developers in their decision-making to design product and plant. The alternator is the electricity generator in the automobile vehicle which produces the needed electricity. LCA and LCC are used to assess three different alternator design scenarios (namely conventional, lightweight and ultra-lightweight). The LCA and LCC results show that the conventional alternator is the most promising one. LCSA of three different locations (Germany, India and Sierra Leone) for setting the remanufacturing mini-factory, a worldwide applicable container, are investigated on all three different sustainability dimensions: LCA, LCC and SLCA. The location choice is determined by the SLCA and the design alternatives by the LCA and LCC. The case study results show that remanufacturing potentially causes about 12% of the emissions and costs compared to producing new parts. The conventional alternator with housing of iron cast performs better in LCA and LCC than the lightweight alternatives with aluminium housing. The optimal location of remanufacturing is dependent on where the used alternators are sourced and where the remanufactured alternators are going to be used. Important measures to improve the sustainability of the remanufacturing process in life cycle perspective are to confirm if the energy efficiency of the remanufactured part is better than the new part, as the use phase dominates from an environmental and economical point of view. The SLCA should be developed further, focusing on the suitable indicators and conducting further case studies including the whole life cycle. - Background The alternator is the automotive part with the highest remanufacturing rate [1]. The function of the alternator is to deliver electrical energy to charge the battery and to the on board equipments like light [2]. Remanufacturing can play an important role as a way to close the material cycles and thereby contribute to less material and energy use [1,3-7], which are the important steps to realise a sustainable development. However, in a life-cycle perspective, not only the production or remanufacturing phase but also the use stage is needed to be taken into account. In the use stage of engines and generators, energy use, associated emissions and costs are of high concern [8]. Up to now, few studies have looked at the whole life cycle of automotive parts that requires energy in the use phase including remanufacturing of the used parts [9]. Sustainability encompasses not only the environmental dimension, but also social and economic ones, as it is defined by the Brundtland Commission [10]. Consequently, a methodology to measure sustainability is getting extremely important. The measurement of the environmental dimension of sustainability is the most mature method of the three. LCA is a standardised method [11,12] widely used to investigate the potential environmental impacts of products and services through the whole life cycle from cradle to grave [13,14]. The life cycle approach helps to avoid shifting of burden from one phase to another. Life cycle costing (LCC) is proposed for the assessment of the economic dimension of sustainability. LCCs have been used since the 1930s [15]; however, it is a relatively new tool within sustainability assessment. The Society of Environmental Toxicology and Chemistry (SETAC) working group on LCC [16] classifies three types of LCC conventional, environmental and societal LCC and considers the method of environmental LCC [16] currently as the most suitable for combining with LCA [15,17,18]. Social life cycle assessment (SLCA) is the life cycle tool to assess the potential social and socio-economic impacts of the products and their consumption throughout their life cycles [19]. To combine LCA, environmental life cycle costing (LCC) [16,20] and SLCA [19], a methodology called Life Cycle Sustainability Assessment (LCSA) [21] has been suggested and can be formally expressed in the symbolic equation [22-25]: LCSA LCA LCC SLCA; 1. LCSA = Life cycle sustainability assessment, 2. LCA = Environmental life cycle assessment, 3. LCC = Environmental life cycle costing and 4. SLCA = Social life cycle assessment Based on the well-known depiction of sustainability, where the three dimensions of environment, economy and society intersect, as depicted in Figure 1a, the LCSA can be illustrated synchronously as previously described (Figure 1b). Similar to the LCA method, environmental LCC and SLCA are life cycle approaches which have been proven useful to prevent shifting of burden from one process to another in the product life cycle [23]. Despite the long history of conventional life cycle costing, the environmental LCC is a relatively new method in a sustainability context [20]. SLCA is still in its infancy, where one of the current focuses is developing the indicators to be used [22]. This paper presents the results from a multidisciplinary research project applying LCSA on different scenarios for remanufactured alternators - three different countries and three different alternator designs are investigated - and thereby lead contribution to the development of the LCSA methodology. The whole life cycle is considered (for the LCA and the environmental LCC), but the main focus in this paper is on the remanufacturing process. Thereby, the measurements to improve the sustainability of the SLCA LCA Figure 1 Dimensions of sustainability and life cycle sustainability assessment. (a) The three dimensions of sustainability based on [26]. (b) Life cycle sustainability assessment (LCSA) consists of environmental life cycle assessment (LCA), environmental life cycle costing (LCC) and social LCA (SLCA). remanufacturing have been identifie (...truncated)