Circular economy has gained increased attention in both academia and industry. One of the main hurdles in implementing viable circular manufacturing systems in industry is the anticipation of future economic and environmental benefits in a circular supply setting, combined with product design decisions. Although circular practices, such as remanufacturing and reuse are often beneficial for original equipment manufacturers in closing the loop and realising business benefits, it is enormously challenging to match early design decisions at a single component level to future unknown recovery operations. Therefore, this paper presents a mixed agent-based and discrete-event simulation model to quantify economic and environmental impacts resulting from chosen circular design strategies. The feasibility of the model is tested using a case study product of an electric machine from the heavy-duty vehicle industry. Results show that an additional design investment of 10.6% can reduce the average cost of an electric machine by 18.6%, material demand by 14.7% and cradle-to-gate impact by 38.7% on average. In the context of electric machines, the most sensitive parameters of the circular supply chain are the success rate of remanufacturing and reuse operations, the lifetime length and the degradation speed.

The shift to a Circular Economy (CE) is crucial for addressing resource scarcity, price volatility, and environmental impacts. By 2030, CE could reduce the EU's material consumption by 32% and greenhouse gas emissions by 48%. However, remanufacturing which is a key strategy in CE remains low, with a remanufacturing intensity of just 1.1%, in the EU automotive sector. SCANIA, like other OEMs, remanufactures limited components, while truck cabins, with their complex material mixes and high emissions, remain largely unexplored in terms of circularity. Most cabin components, including up to 300 kg of plastics per cabin, are incinerated or landfilled at end-of-life (EoL). There is an economic and environmental opportunity in reusing, refurbishing, or recycling cabin components. To optimize cabin circularity and business potential, understanding current material flows and developing a circular business model is critical. The CIRCAB project aimed at studying the feasibility of enhancing cabin circularity by creating an ecosystem with value chain partners to optimize material handling at every stage. The CIRCAB project concluded with its intended outcomes, including extensive knowledge about the current state of plastic flows across different actors, industrial best practices, business drawbacks and the potential for reusing plastic components from production and end-of-life (EoL) trucks, technological limitations and opportunities in recycling, and legal frameworks promoting the circularity of plastics used in the automotive sector. The CIRCAB project has concluded with a strong urge and commitment for a radical shift that is needed to enhance the circularity of plastic components.

Remanufacturing is vital in circular business models, offering a sustainable way to restore products and reduce resource consumption. In the automotive industry, remanufactured parts are commonly used as spare parts, although their volumes in the market remains limited compared to new spare parts. One main challenge in increasing adoption of remanufacturing is that economic and environmental effects of reverse logistics operations are unknown. This research develops a simulation-based decision support tool for assessing reverse logistics operations in the automotive aftermarket, evaluating the economic and environmental impact of remanufactured versus newly produced spare parts. Using a combination of agent-based and discrete event methods, the simulation analyzes the effectiveness of Scania's reverse logistics network using diesel particulate filter as case study. The findings demonstrate remanufacturing advantages in cost (-82%), carbon footprint emissions (-92%), and virgin material savings (-99%) over new production, therefore supporting the integration of remanufactured parts into circular business models.

The transition towards a circular economy (CE) has become inevitable to mitigate challenges of resource scarcity and resource price volatility, as well as minimize the climate and environmental impact. By 2030 for the EU, CE could result in a reduction of primary material consumption by 32% [1]  and greenhouse gas emissions by 48 % compared with the 2012 levels[2]. The European Environment Agency[3] estimates that the net benefits for businesses by implementing CE measures range from EUR 245 billion to EUR 604 billion. Although these figures are promising the reality is rather bitter. Remanufacturing[4] which is one of the most important strategies in implementing CE principles in the manufacturing industry, has an intensity (ratio of remanufacturing to new manufacturing) of only 1.9%, while the intensity in the automotive sector is 1.1% in the EU[5]. This means that the remanufacturing intensity in all sectors needs to be increased significantly to exploit the untapped potential of CE. 

At Scania and many other Original Equipment Manufacturers (OEMs) and Suppliers (OESs), the flow of new components for the production of new vehicles is handled independently from the flow of remanufactured components that are intended for the aftermarket. The gearbox is one such component. For any company to intensify its circularity to the level that society needs without cannibalising the aftermarket business, integrating remanufactured components in the production of new products is essential[6]. However, OEMs have thus far not attempted to systematically integrate remanufactured components in the new products.

The iReGear project presents the first successful demonstration of integrating a remanufactured gearbox into the production line of new trucks and serves as an objective demonstration that the remanufactured gearbox performs as good as a new one. The project also investigated and confirmed that there are no legal obstacles to using remanufactured components in new trucks, provided that customers are informed about it. Additionally, it has been established that there are no existing examples of remanufactured components being used in new vehicles.

Two major Scania customers have indicated their willingness to accept remanufactured components in new trucks, as long as the performance and competitiveness of the trucks are not compromised. They also expressed a readiness to pay more for such a solution, given that it reduces overall emissions, and their customers are willing to pay for these added environmental benefits.

An attempt has also been made to formulate two basic equations and a procedure to estimate the economic and environmental potential of scaling up the use of remanufactured gearboxes in new trucks. Moreover, it is also estimated that the current remanufacturing intensity of the gearbox is only 0.4% relative to the number of new gearboxes produced by Scania each year indicating a significant potential for increasing the volume of remanufactured gearboxes.

This research makes a significant contribution to the ongoing discussion and provides the first evidence to support the argument that it is feasible to envision future manufacturing organizations seamlessly integrating manufacturing and remanufacturing operations to develop Circular Manufacturing Systems that consume fewer resources, produce fewer emissions, and cost less without compromising quality and performance. Future research should advance with a vision toward a Circular Manufacturing System, where the integration of remanufactured components becomes the status quo. Along the way, efforts should also focus on enhancing the efficiency of remanufacturing by addressing the shortcomings of conventional approaches.

Life Cycle Assessment (LCA) is a well-known methodology used to calculate the environmental impacts of a product across its life cycle. The industrial machines used to manufacture consumer products are generally heavy, bulky, and have a complex product structure which makes their environmental assessment using LCA difficult as well as time and resource-intensive. Few studies have conducted LCA of complex industrial machines. The paper presents an LCA of a jet printing and dispensing machine (MY700), an industrial machine used in the production of printed circuit boards (PCBs) carried out using ReCiPe 2016 (Hierarchist) impact assessment methodology. In this study, the use phase of the machine accounted for 91% of the total environmental impacts. The compressed air and electricity consumed in the use phase of the machine were the major environmental hotspots. Additionally, some measures to minimize energy and compressed air use are also discussed. The methodology proposed in this article can be adopted by practitioners to conduct LCA of other industrial machines. The results of this study can help the machine manufacturers to undertake relevant eco-design activities as well as a comparison of different versions/machines in the product family for their environmental impact.

The transition to circular manufacturing systems (CMS) is crucial for achieving sustainable growth, addressing the environmental concerns and resource scarcity challenges. Shifting towards CMS requires a systemic approach that integrates value proposition models, product design, and supply chains (SCs). Circular supply chains (CSCs) emerge as a core pillar of CMS, incorporating value delivery, use, recovery, and reuse. CSCs are inherently more complex and dynamic than linear SCs requiring a holistic analysis approach to capture their complex and dynamic attributes. This research proposes an integrated analysis framework combining qualitative and quantitative approaches to explore the complexities and dynamics of CSCs and assess their economic, environmental, and technical performance. Through the lens of two different CMS implementation case studies, one in automotive parts remanufacturing and one in white goods manufacturing, this research illustrates the framework's applicability. In the automotive case, centralizing core management activities was found to improve economic performance by 50-54 %. However, the introduction of regional logistics hubs, while economically efficient, led to a 20 % increase in CO2-equivalent emissions. On the other hand, the white goods case study highlighted the trade-offs in centralizing end-of-life recovery facilities, where financial savings of up to 60 % were offset by increased transportation costs and increased CO2 emissions. The analysis of CSCs in these two distinct manufacturing sectors underscores the relevance and flexibility of the proposed framework, providing decision-makers with a tool to examine how different CSCs configurations and strategies impact overall performance. This guidance is crucial for developing optimal CSCs design and implementation strategies.

Stretchable electronics is a new innovation and becoming popular in various fields, especially in the healthcare sector. Since stretchable electronics use less printed circuit boards (PCBs), it is expected that the environmental performance of a stretchable electronics-based device is better than a rigid electronics-based device that provides the same functionalities. Yet, such a study is rarely available. Thus, the main purpose of this research is to perform a comparative life cycle analysis of stretchable and rigid electronics-based devices. This research combines both the case study approach and the research review approach. For the case study, a cardiac monitoring device with both stretchable and rigid electronics is used. The ISO 14044:2006 standard's prescribed LCA approach and ReCiPe 2016 Midpoint (Hierarchist) are followed for the impact assessment using the SimaPro 9.1 software. The LCA results show that the stretchable cardiac monitoring device has better environmental performance in all eighteen impact categories. This research also shows that the manufacturing process of stretchable electronics has lower environmental impacts than those for rigid electronics. The main reasons for the improved environmental performance of stretchable electronics are lower consumption of raw material as well as decreased energy consumption during manufacturing. Based on the LCA results of a cardiac monitoring device, the study concludes that stretchable electronics and their manufacturing process have better environmental performance in comparison with the rigid electronics and their manufacturing process.

Circular Economy (CE) promotes trading functions of a product as aservice instead of selling the product in conventional ways. For a product like ababy stroller, the function means ensuring mobility with infants without needingto own a stroller. This approach of acquiring functions only when needed opensup the possibility to share the same products with multiple users. For a manufacturer that has built its business on a conventional sales model over the decades,this shift may be too radical. Therefore, for the manufacturers, it is important tounderstand consumer perceptions of the service-oriented business model beforeentering this unknown territory. To develop a thorough understanding of consumerperceptions of leasing a stroller instead of buying one, a survey among 200 parentsin Stockholm is conducted. The survey brings out quantitative results such as 39%of respondents are open to leasing and identifies key influencing factors such asconvenience and environmental image that play a key role for the remaining 61%of respondents to choose leasing. This research concludes that a large numberof consumers are open to leasing if a high level of service and environmentallysustainable strollers are offered at a competitive price.

Circular manufacturing systems (CMS) constitute complex value networks comprising a large and diverse set of stakeholders that collaborate to close the loop of products through multiple lifecycles. Complex systems modelling and simulation play a crucial role in providing quantitative and qualitative insights into the behaviour of such systems. In particular, multi-method simulation modelling that combines agent-based, discrete-event, and system dynamics simulation methods is considered more suitable to model and simulate CMS as it allows to capture their complex and dynamic nature. This paper provides a step-by-step approach on how to build a CMS multi-method simulation model in order to assess their economic, environmental, and technical performance for enhanced decision-making. To model and simulate CMS three main elements need to be considered: • A multi-method model architecture where the CMS stakeholders with heterogeneous characteristics are modelled individually as autonomous agents using agent-based, discrete-event, and system dynamics. • An agent environment defined by a Geographic Information System (GIS) to establish connections based on agents’ geographic location. • The product journey resulting from the product's interaction with various CMS stakeholders in the circular value network is traced throughout its multiple lifecycles.

A transition towards circular manufacturing systems (CMS) has brought awareness of untapped economic and environmental benefits for the manufacturing industry. Conventional manufacturing systems already present a high level of complexity in terms of physical flows of materials and products as well as information and financial flows linked to them. Closing the loop of materials and products through multiple lifecycles, as proposed in CMS, increases this complexity manifold. To support practitioners in implementing CMS through enhanced decision-making, this research studies CMS from a complex adaptive systems (CAS) perspective and proposes to exploit methods and tools used in the study of CAS to characterise, model and analyse CMS. By viewing CMS as CAS composed of autonomous, interacting agents, this research proposes a multi-method model architecture for modelling and simulating CMS. The different CMS stakeholders are modelled individually as autonomous agents by integrating agent-based, discrete-event, and/or system dynamics modules within each agent to capture their diverse and heterogeneous nature. The applicability of the proposed multi-method approach is illustrated through a case study of a white goods manufacturing company implementing CMS in practice. This case study shows the relevance and feasibility of the proposed multi-method approach as a decision support tool for the systemic exploration and quantification of CMS. It also shows how a transition towards CMS necessitates a lifecycle approach in terms of costs, revenues and environmental impacts to identify hotspots and, therefore, design circular systems that are viable in both economic and environmental terms. In fact, the analyses of the simulation results indicate how decisions in terms of business models, product design, and supply chain affected the CMS performance of the case company. For instance, implementing a service-based model led to a high number of usecycles (on average six usecycles per washing machine), which, in turn, led to high lifecycle costs and emissions due to more frequent transportation and recovery operations. Similarly, the deployment of long-lasting washing machines, which is a core principle of CMS, led to high manufacturing costs. Due to the high initial costs and a time mismatch between revenues and costs in the service-based model, it required a longer time for the company to reach the break-even point (approximately 23 months). Overall, the case study shows that multi-method simulation modelling can provide decision-making support for a successful implementation of CMS.