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Let us start with defining circular economy, or circularity as it is also commonly referred as. Circular economy is all about reducing waste and prolonging the lifespan of products, components, and materials. It is contrasted to the linear economy where raw materials are processed into products that are consumed and then disposed. Instead of a linear lifecycle, the products, components, and materials are given one or more life cycles when they reach the end of life. The ecosystem perspective is prominent; circular economy is not achieved by a single company – it is a joint effort seen in the entire value chain and on societal level. Moreover, circular economy is a way to achieve sustainable development, i.e., a development that meets the needs of today without compromising the possibility to meet the needs of future generations. Therefore, we must apply a now-centred perspective as well as a future-centred perspective on circularity. All these perspectives are distinguishable in the definition of circular economy given by Krichherr et al. (2017, p. 229)1:

“…an economic system that replaces the ‘end-of-life’ concept with reducing, alternatively reusing, recycling and recovering materials in production/distribution and consumption processes. It operates at the micro level (products, companies, consumers), meso level (eco-industrial parks) and macro level (city, region, nation and beyond), with the aim to accomplish sustainable development, thus simultaneously creating environmental quality, economic prosperity and social equity, to the benefit of current and future generations”.

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How to assess the “circularity” of e.g., a company or a nation? For businesses, the Science Based Target Initiative (SBTi) allows for formulating environmental targets that comply with the Paris agreement of not exceeding a global warming of 1.5°C. Thousands of businesses have started using science-based targets aiming at net zero emissions by 2050. SBTi reports that the global emissions increased by over 3% from energy and industry between 2015 and 2019, but also that the emissions in the SBTi companies decreased by 25% in the same period. Circularity is an important aspect for achieving the sustainability development goals, or Agenda 2030, agreed upon by the United Nations in 20152. The level of goal fulfilment spans from 39% to 87%, with Finland, Sweden, and Denmark being the top three countries 3. If we measure global circularity in terms of virgin material use, the trend is rather discouraging. According to the recently launched Circularity Gap Report4 the world is 7.5% circular, which could be compared with 9.1% in 2018 and 8.6% in 2020.

Very disappointing reading, you may think. On the upside, there is an immense potential in applying circularity on all levels to reach the set targets. Several circular strategies exist that could be applied to reduce virgin material use and prolong the lifespan of products, components, and materials. The 10R model5 is commonly used to describe circular strategies from less circular to highly circular (see Figure 1). On the bottom (R9 and R8), we find strategies to recover some value from material, such as using biomaterial waste as fuel in heating plants or making toilet paper out of scrapped books. The next five strategies (R7-R3) aim to prolong the lifespan of a product.

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Figure 1. Circular strategies and the role of maintenance as a facilitator

Repurposing and remanufacturing are strategies for giving the product or its components a new life cycle either by restoring or altering the functionality while refurbish, repair, and reuse are strategies aiming at prolonging the existent life cycle and functionality of the product. An old school bus could for instance be sold on the second-hand market, undergo maintenance, or be repurposed as a mobile home. The final three strategies (R2-R0) aim to reduce the resources in production and consumption.

Reduced resources in the production may address energy consumption or material by increasing the availability and quality rate or reducing performance losses. Reducing resources in consumption may be achieved by offering a product as a service or by offering performance instead of a product. The latter could for instance be in form of renting or leasing a car instead of buying and owning one as a consumer, or by arranging the transportation need in other ways such as train or bus services.

Maintenance plays a huge role in achieving high level of circularity. Let us start by looking at the rethink and reduce strategies. Rethinking strategies rely on companies acting as service providers rather than producers and sellers of products. The ownership of the product that creates the customer value is kept by the provider, who benefits in an asset management strategy for these products. The longer the lifespan of the asset providing value, the higher life cycle profit might be achieved. From a production perspective, it is well known that efficient asset management in the form of preventive maintenance strategies has significant impact on the production processes in terms of higher availability, dependability, and quality output.

For the strategy reuse, maintenance plays an indirect role. The main idea is to resell the product on the second-hand market. For products in bad shape, maintenance in the form of cleaning, repair, or the similar is necessary. This could be conducted by the second-hand dealer or by a specialised contractor offering maintenance services. If maintenance is not done before the sales, the new owner might need to buy maintenance services instead.

Maintenance is a direct activity in repair and refurbish. For fulfilling these circular strategies, maintenance services are offered to the owner of the product. Maintenance is, from this perspective, a business model rather than an operations strategy. In this context, refurbishing is the same thing as doing maintenance in the end-of-life of the product. We can assume that the product has a partial or complete functional failure, and that corrective and preventive maintenance is needed. The maintenance need is, thus, higher for this product than for a product in need of repair.

Lastly, we have the remanufacturing and repurposing strategies. Cleaning and repair, i.e., common maintenance activities, are necessary sub-activities in the remanufacturing or repurposing process. Remanufacturing is defined as ”returning a used product to at least its original performance with a warranty that is equivalent or better than that of the newly manufactured product”6. If we scrutinize the definition of remanufacturing, it is obvious that maintenance plays a larger role, as remanufacturing aims at regaining the function of a product to at least its original performance. Based on this reasoning, remanufacturing could be viewed as a maintenance activity on the industrial scale.

In conclusion, we see that maintenance is a crucial factor for achieving circular strategies both within the company and throughout the full life span of the product. Maintenance allows for reduction of virgin raw material by making the products and production more efficient. It prolongs the lifespan of products and components by appropriate services for individual users and businesses, and by centralized and industrialized maintenance of products at the end-of-life.

Text: Mirka Kans, Associate professor (docent), Chalmers University of Technology
Images: stockphoto

References
[1] Kirchherr, J., Reike, D., & Hekkert, M. (2017). Conceptualizing the circular economy: An analysis of 114 definitions. Resources, conservation and
recycling, 127, 221-232.
[2] https://unstats.un.org/sdgs/report/2023/
[3] https://dashboards.sdgindex.org/rankings
[4] https://www.circularity-gap.world/
[5] http://www.pbl.nl/sites/default/files/cms/publicaties/pbl-2016-circular-economy-measuring-innovation-in-product-chains-2544.pdf
[6] British Standard Institute, 2009. BS 8887-2:2009 Design for manufacture, assembly, disassembly, and end-of-life processing (MADE) Terms and definitions.