Research projects:
Cross cutting theme 1

Sustainable manufacturing of electrical machine components for the circular economy

Led by NMIS

GC X1 is a cross-cutting theme within the FEMM hub focused on the sustainable manufacture of electrical machine components, with a view to implementing circular economy strategies. Sustainability is a key component of any future machine design, and as such, this Grand Challenge was updated to be a crosscutting theme of all FEMM hub work packages. This will ensure that a clear focus is given to the sustainability of future electrical machines. This work package aims to: 

• Reduce use of finite materials in next generation of machines and enable recapture cycles to reuse materials 

• Give consideration to energy efficient manufacturing 

• Implement Design for Disassembly strategies for future electrical machines, including opportunities for reuse, recycle, remanufacture etc. 

• Develop a circular economy approach for an electrical machine supply chain that uses data driven intelligence based on product data 

Circular economy model Led by NMIS Page 45 Current electrical machines are manufactured using a linear economy model that takes raw material, transforms it into products, and then discards them to waste without considering the environmental consequences. The circular economy (CE), as shown below, is a systemic approach to economic development designed to benefit businesses, society, and the environment. Adopting circular economy approach does not dictate one solution to solve all the issues, but is an alternative way of approaching the problem, and provides many solutions that can be adopted. 

Often, when “sustainability” is mentioned within the engineering community, the first response is often linked to recycling material. Although recycling of materials will be an important factor in the drive towards circularity, it should not be considered the first or only solution. The circular economy hierarchy is shown below, a ranked order with the most favourable solutions at the top, i.e. those that require less energy consumption and material usages, and the least favourable solutions at the bottom. This hierarchy doesn’t imply that activities such as recycling or remanufacture should not be included in a comprehensive circular economy strategy, but other strategies, such as redesigning components in order to reduce material waste and design for disassembly and repair, should be prioritised. 

Grand Challenge X1, in conjunction with PhD student Leigh Paterson, has been looking at ways of quantifying the various issues around current production and through-life management of electrical machines. A paper has been accepted in the journal Sustainability entitled “The Juxtaposition of Our Future Electrification Solutions: A View into the Unsustainable Life Cycle of the Permanent Magnet Electrical Machine” [1], and will be published in early 2024. Electrical machines provide a cleaner alternative for fossil-based technologies across multiple sectors including transport and energy. However, the products are often manufactured in a way that does not take into account their end of life, with common disposal techniques including shredding, burning, and landfill disposal. For electrical machines to be a truly sustainable solution, improvements need to be made from material sourcing, through manufacturing, to design for disassembly. This paper summarises the current demand and challenges for electrical machines, and follows each component through their typical lifecycle. The key aim of this paper was to present the typical life cycle of permanent magnet electrical machine as it stands today, and to demonstrate the environmental issues associated with the current linear life cycle. Alternative practices have also been discussed in the paper, with the short term aim to ease the immediate environmental burden of these products, and the ultimate aim to design and manufacture fully sustainable electrical machines. Circular economy hierarchy Page 46 Continuing on the theme of a fully sustainable electrical machine, GC X1 has lead a cross-challenge work stream including all partners of the FEMM hub to understand how to design an electrical machine that has 100% value retention, i.e. a zero-waste machine. We began this work stream with a workshop using TRIZ (Theory of Inventive Problem Solving), which is a structured brainstorming tool used for early stage, conceptual idea generation. The first step was to identify key system components that could hinder the manufacture of a zero-waste machine, and determine the primary benefits that such a machine should possess. Potential solutions were then generated using a ‘9-box’ process that enables the mapping of any system in time and scale. In time includes before, during, and after use, i.e. manufacture, in-use, and end of life; and in scale includes sub-system, system, and super-system, i.e. materials, components or full machine, and wider system context (e.g. full vehicle/aircraft, or wider supply chain). This work led to identifying three work streams to take forward: 

Theme 1- Interlocking meta-surfaces: how can mechanical interlocking or reversible assembly process be implemented in high value electrical machines 

Theme 2- Injection over-moulded coil modules: can we use injection moulding to manufacture modular windings that are optimised for disassembly and repair 

Theme 3- Case study comparing disassembly of different machines: how do we measure ‘success’, and how do different machine topologies compare. 

These three work streams have now kicked off, and have representation from all grand challenges, and aim to answer some of the most challenging questions around the future sustainability of electrical machines. In 2023, the FEMM hub published its first roadmap that highlights the development requirements for electrical machines to achieve a net zero future [2]. This roadmap was well received within the community, and as a follow up, GC X1 is leading in the development and publication of a positioning paper on the circular economy of electrical machines. This paper will summarise information from key stakeholders in industry and research, highlighting the major challenges and opportunities for the UK to lead the way in manufacturing fully sustainable, high value electrical machines. The FEMM hub team at NMIS hosted a masters student in 2022/23 in the area of electrical machine sustainability. Eilidh Pearce completed her masters thesis on “Sustainable Design of Generators for Offshore Wind: Life Cycle Comparison of Lightweight Rotor Structures” under the supervisions of GC X1 leader Dr Jill Miscandlon, and was supported by Dr Pablo Sola at Edinburgh Napier University. Dr Sola previously received funding from the FEMM hub for a feasibility study “CEDEMSARI- A critical evaluation of large scale direct drive wind turbine electrical machines manufacturing techniques considering sustainability aspects and recyclability issues”. The collaboration in previous years has led to Dr’s Sola and Miscandlon co-supervising a PhD studentship that will be filled in early 2024