Sustainability of Permanent Rare Earth Magnet Motors in (H)EV Industry

Abstract

It is clear that hybrid/electric vehicles [(H)EVs] are only as green as the materials and energy that they use. According to MIT, the production and processing of rare earth elements (REEs) found in (H)EVs come with their own hefty environmental price tag (K. Bourzac, Rare-Earth Crisis, MIT Technol. Rev., 114(3):58–63, 2011). These damages include radioactive wastewater leaks and ‘slash-and-burn processes’ required to manufacture and separate REEs. Some life cycle assessment (LCA) studies found that the carbon advantage of an electric vehicle over an internal combustion engine vehicle is small considering the production/manufacturing and end-of-life stages (C.-W. Yap, China Ends Rare-Earth Minerals Export Quotas, Wall Street Journal, updated 5 Jan. 2015; D.S. Abraham, War Over the Periodic Table, Bloomberg View, 23 Oct. 2015). However, sustainability is not only about environmental impacts, but also concerns other sustainable development principles such as economic viability and social well-being. Permanent magnet (PM) rare earth motors are most widely used in the (H)EV industry, but the price volatility of REEs does not make them an economically sustainable option. The research involving the potential social impacts of the extraction and use of rare earths for the automobile industry is examined. This review addresses the technical aspects of PM motors and how it contributes to or withdraws from the sustainability of (H)EVs. This paper undertakes a review of the literature and the present situation of sustainability of REEs in the electric vehicle industry. Furthermore, this paper highlights the areas of sustainability research considered by academic and industrial representatives to be essential for cleaning up the clean technology. The intention is not to declare rare earth PM motors sustainable, but to analyze their contribution to sustainability in terms of technical, social, environmental, and economic aspects. Ultimately, the potential opportunities toward a more sustainable rare earth PM motor are revealed.