Environmental impact of traction electric motors for electric vehicles applications
The expansion of the electric vehicle (EV) market will bring changes in the type of environmental impact generated by the transport sector. This will be partially associated to the introduction of new technologies for energy storage and powertrains, including electric motors technology, which can play a critical role for the EV. To assure its optimal performance, key components and innovative materials are integrated in current motor designs. Such is the case of permanent magnets (PM), commonly made of rare-earth elements, which have a history of ecological concerns related to its mining. The goal of the paper is to study novel traction e-motors and to assess the influence of its components, in the environmental performance of the motor and the electric vehicle.
In this study, a life cycle assessment (LCA) is performed, including the manufacturing, use, and end of life stages of a traction electric motor for EV applications. A comparison is presented, where the rare-earth magnets are replaced by ferrite magnets, under several efficiency scenarios. Average European conditions are considered for framing the modeling. A functional unit of 1 km driven by the vehicle is used.
Results and discussion
Twelve impact categories were selected to present the potential environmental impact of the motors. Energy consumption during the use stage was identified as a hotspot responsible for an important share of the impact. The amount of energy consumed is highly dependent on the efficiencies of the powertrain, which is why improving efficiency should be regarded as crucial for decreasing the environmental damage produced by the motor. The use of rare-earth magnets during manufacturing does not represent a significant share of the impact, as they only take 2 % of the total mass. Other components, including laminations, housing and windings were instead recognized as more significant than the mangets, mainly for climate change, toxicity of humans, soil and water bodies, as well as metal depletion. The use of alternative materials for rare-earth magnets can contribute in the reduction of the potential impact, as long as the overall efficiency of the motor remains the same or increases.
Based on the study results, it can be concluded that the environmental performance of traction motor is closely tight to its efficiency. Selection of materials during design should focus more on preserving or improving the efficiency of the motor, than on materials with low environmental impact during production.
KeywordsEfficiency E-motor Environmental performance EV LCA Powertrain
The authors are grateful to the European Commission for the support to the present work, performed within the EU FP7 project “SyrNemo” (Grant Agreement No 605075).
- ABB (2002) Environmental product declarations. http://www.abb.com/cawp/abbzh258/3d76091aeb235c70c12569ee002b47f4.aspx. Accessed 15 Nov 2014
- Croezen H, Bello O (2003) Environmental profiles of motors and transformers. CE, DelftGoogle Scholar
- Cuenca R, Gaines L, Vyas A (2009) Evaluation of electric vehicle production and operating costs. Center for Transportation Research, Energy Systems Division, Argonne National Laboratory, ArgonneGoogle Scholar
- Deprez W, Pardon L, De Keulenaer H, Herrmann C, Driesen J (2006) Ecodesign toolbox for electrical equipment. 13th CIRP international conference on life cycle engineering. LeuvenGoogle Scholar
- European Commission (2010) ILCD Handbook: analysing of existing environmental impact assessment methodologies for use in life cycle assessment. First edition. JRC Reference Report, European Commission – Joint Research Centre. Publications office of the European Union, LuxembourgGoogle Scholar
- European Commission - Joint Research Centre - Institute for Environment and Sustainability (2011) International Reference Life Cycle Data System (ILCD) Handbook - Recommendations for life cycle impact assessment in the European contextGoogle Scholar
- European Commission - Joint Research Centre - Institute for Institute for Energy and Transport. (2012) Driving and parking patterns of European car drivers - a mobility surveyGoogle Scholar
- European Commission - Research Directorate General. (2007) The Seventh Framework Program (FP7)Google Scholar
- Gieras J (2013) Permanent motor magnet technology: design and applications. In: Applications of permanent magnet motors, 3rd ed. CRC Press, New York, pp 1–33Google Scholar
- Hischier R, Classen M, Lehmann M, Scharnhorst W (2007) Life cycle inventories of electric and electronic equipment: production, use and disposal. Final report ecoinvent data v2.0 No. 18. Swiss Centre for Life Cycle Inventories, DübendorfGoogle Scholar
- I. S. ISO 14040 (2006) Environmental management - Life cycle assessment - Principles and frameworksGoogle Scholar
- I. S. ISO 14044 (2006) International standard assessment — Requirements and guidelinesGoogle Scholar
- International Energy Agency (2011) Energy-efficiency policy opportunities for electric motor-driven systems. 2011. http://www.iea.org/topics/energyefficiency/publications/ . Accessed 15 Dec 2014
- International Energy Agency (2012) European union −28: electricity and heat 2012. http://www.iea.org/statistics/statisticssearch/report/?country=EU28&product=electricityandheat&year=2012. Accessed 10 Nov 2014
- U.S. Department of Energy (2011) Critical materials strategy – 2011 Report and summary. Http://energy.gov/epsa/initiatives/department-energy-s-critical-materials-strategy. Accessed 01 Dec 2014
- UNECE (2013) Regulation No. 101 Uniform provisions concerning the approval of passenger cars powered by an internal combustion engine only, or powered by a hybrid electric power train with regard to the measurement of the emission of carbon dioxide and fuel consumption and/or the measurement of electric energy consumption and electric range, and of categories M1 and N1 vehicles powered by an electric power train only with regard to the measurement of electric energy consumption and electric rangeGoogle Scholar
- Zeraoulia M, Benbouzid M, Diallo D (2006) Electric motor drive selection issues for HEV propulsion systems: a comparative study. IEEE Trans Veh Technol, Inst Electr Electron Eng (IEEE) 55(6):1756–1764Google Scholar