Reduced use of rare earth elements for permanent magnet generators: preliminary results from NEOHIRE project

The use of so called Rare Earth Elements (REEs) for the production of permanent magnets (PMs) is increasing worldwide due to the needs of numerous industrial sectors. REEs are described in literature as critical materials due to the uncertainties related to cost instability and due to the potential environmental and social impact associated to their production cycle. The NEOHIRE project aims at reducing the amount of critical materials installed on wind turbine generators, developing bonded magnets characterized by reduced use of REEs. The project includes the study of alternative alloys and of their specific production processes, the engineering of machines optimized for the characteristics of the newly developed magnets, the proposal of recycling processes tailored for different types of PM; life cycle analyses aimed to estimate environmental, economic and social impact are also performed to verify the sustainability of the proposed technology. This paper describes the results of the first phase of such life cycle assessment, which started with inventory definition. The steps for PM production have been characterized, identifying materials, energy use and substances used as input; sintered PMs are used as reference for a comparison with bonded PMs. The construction of the inventory has been done considering small scale processes performed during research activity, which are characterized by a different specific energy consumption in relation to industrial-scale ones. Therefore, a thermal model for the assessment of the performances of scaled-up processes is proposed, being suitable for the estimation of energy consumption during heat-treatments. A provisional scenario for new bonded PMs production is then adopted for environmental impact assessment. Results, which have to be considered as preliminary, show the main relevance of various phases in determining the impact and a brief comparison with sintered PMs-based machines.