The European Union increasingly frames the Circular Economy as a means to advance its Open Strategic Autonomy vision, a shift reflected in policies on the supply security of Critical Raw Materials. Titanium metal is central to this debate given its importance for aviation and defence and the European structural reliance on external suppliers. However, two significant limitations persist in research assessing how circular strategies contribute to its supply security. First, no integrated, system-wide assessment explicitly quantifies the security gains of circular interventions in both material and economic dimensions. Second, while policy narratives link circularity to strategic autonomy, empirical assessments rely on isolated indicators not directed by clearly defined strategic objectives. As a result, the security implications of circular economy strategies for titanium remain insufficiently operationalised.

To address these gaps, the thesis develops an analytical framework and applies it to titanium supply security under a national security discourse. Within this perspective, supply security is defined along two measurable dimensions of strategic autonomy: material self-sufficiency and domestic value creation, which guide the selection of indicators used to evaluate circular interventions. The framework is applied by reconstructing the current titanium supply chain in the European Union through Material Flow Analysis, identifying key stocks, flows, and external dependencies. Two scenarios in the aviation sector up to 2040—enhanced domestic recycling and aircraft lifetime extension—are then modelled using dynamic MFA to assess material effects and Multi-Regional Input–Output analysis to evaluate impacts on domestic value creation.

The baseline analysis shows that the current titanium configuration in the European Union is characterised by two structural vulnerabilities: near-total import reliance at the midstream level and substantial losses through pre-consumer scrap generation during component manufacturing. Enhanced domestic recycling delivers the strongest improvements in both dimensions of supply security, increasing material self-sufficiency by approximately 35% and generating an estimated €43.7 million in domestic value added and around 500 jobs. However, these gains are largely driven by retention and reprocessing of pre-consumer scrap rather than end-of-life recovery. Even under existing remelting capacity, secondary feedstock would be depleted within roughly a decade, limiting its structural contribution. Moreover, more than half of pre-consumer scrap remains bound to buyback agreements with the United States, constraining strategic autonomy. Aircraft lifetime extension performs more modestly in static comparisons, delivering roughly half the economic gains of recycling. Yet by slowing inflow requirements, it acts as a demand-side buffer, suggesting that strengthening maintenance, repair and overhaul capabilities represents a relevant complement to recycling efforts.

Overall, the thesis shows that circular economy strategies can support strategic autonomy objectives, but their effectiveness depends on a holistic, system-wide, and dynamic perspective on the supply chain. Conceptually, it situates circular interventions within a resource security framework bridging industrial ecology and international relations. Methodologically, it introduces a hybrid approach combining dynamic Material Flow Analysis with Multi-Regional Input–Output modelling to assess material flows and economic interdependencies simultaneously. Empirically, the titanium case illustrates both the opportunities and limits of circular interventions, informing policy and industry strategies to strengthen domestic control and industrial capacity.


Github: https://github.com/SGhirlandi/Ghirlandi_2026---Thesis---Supplementary
Zenodo: https://doi.org/10.5281/zenodo.18055825

This study addresses a research gap in understanding how telecommunications companies can become more resilient by examining organisation level flows of critical raw materials (CRMs) in optical transport network (OTN) equipment. While previous research has quantified CRM stocks and flows in consumer electronics, the material dynamic behaviour of fibre optical equipment, specifically amplifiers and transponders remain under investigated. In particular, there is little quantitative and time dependent analysis of how CRMs embedded in fibre optical equipment circulate within the network of KPN.

This gap raises the following research question: What strategies can KPN implement in their operations to secure a resilient supply chain of critical raw materials embedded in optical transport network equipment?

To answer this question, a dynamic material flow analysis (dMFA) was developed for amplifiers and transponder deployed by KPN in the Netherlands over the period 2024–2045. First, internal desk research and expert consultation with optical network architects provided insight into equipment lifespans, failures, and the build-up of the network. Next, data from original equipment manufacturers (OEMs) and similar case studies quantified the CRM contents, leading to mapping of 16 CRMs: erbium, bismuth, thulium, germanium, praseodymium, silicon, antimony, boron, magnesium, manganese, nickel, palladium, ruthenium, silicon, strontium, tantalum, titanium, tungsten and yttrium. These inputs enabled the integration of a stockfidriven dMFA model projecting annual primary CRM inflows, stocks, and outflows. Four scenarios were modelled to address uncertainty: (1) businessfiasfiusual, (2) AI driven
growth, (3) a circular and sustainable economy and (4) technology & innovation representing a hybrid scenario combining moderate growth with circular interventions. A Monte Carlo sensitivity analysis assessed the extended uncertainty for stock accumulation and the impact of the selected parameters.

Results indicate that, under high growth scenarios, demand for key CRMs in amplifiers and transponder printed circuit boards rises increasingly fast, with a stable period between 2033 and 2038 due to capacity doubling and a continued exponential growth after 2038 resulting in a demand increase between factor 9 and 14 for the low and high scenario respectively. Possible leading to issues in the future as competing sectors such as solar photovoltaics, wind turbines and electrolysers are also expected to grow rapidly in the EU and globally. With primary use rates indicating that higher recycling yields still cannot account for the demand increase periods. Whereas experimentation of low, medium and configurations
of circular economy strategies have shown that individual strategies cannot reduce more than 30% of primary material demand in 2045. A combined strategy however, resulted in higher savings, while expected savings amount to higher reductions due to the dampening of lifetime extension on recycling and reusing practices. Combining literature surrounding the feasibility of resilience strategies on a firm level with the temporal and magnitude of the strategies led to managerial implications for KPN. With proposed short term (2025 - 2033) strategies focusing on reduction and lifetime extending strategies, whereas medium term (2033 - 2038) strategies emphasize recycling and reusing of equipment. With long term (2038 - onwards) strategies aimed at reducing material needs. However, the study also shows the high dependency of KPN on supplier product design choices and the limited control on upstream
influence.

In order to further enhance the study, it is firstly recommended to investigated to conduct a more thorough stakeholder analysis to get a better understanding of the power and interests of the relevant players in the value chain. In addition to an extension of the economic importance criteria tailored to telecom companies and an investigation on methods to integrate higher data efficiency across the optical transport network. With a final recommended study surrounding the upscaling of the equipment to magnify the impact of the fibre optic sector on CRM demand beyond the Netherlands.

Most electronic devices depend on Critical Raw Materials (CRMs) to be produced or repaired.
As such, this increasing dependency represents an emerging threat to the resilience of modern technological systems; without these materials, essential devices such as servers and modems could become inaccessible. Most CRMs lack short-term substitutes and are often sourced from regions with low levels of governance or complex geopolitical relationships with the European Union (EU). In addition to supply risks, the primary production of CRMs is associated with environmental impacts such as resource depletion, acidification, biodiversity and greenhouse gas emissions. These dynamics emphasize the need for innovative solutions that reduce dependency on primary materials, for which a suggested approach is increased circularity.
Therefore, this study addresses the dependency on primary CRMs by exploring strategies to reduce or slow primary material inflow through circular practices, focusing on the end-of-life (EoL) stage of consumer telecommunication products. This is done through static (bookkeeping) and dynamic Material Flow Analysis (MFA), applied within the Dutch context and in collaboration with telecom provider KPN. KPN currently applies circular measures, such as product reuse and recycling, to some of its distributed devices. However, a comprehensive overview of CRM quantities within product flows, as well as a structured outlook for future CRM circularity, were not yet developed. Consequently, this study addresses this gap by providing insights in applied CRM circularity practices and future strategies, based on one of KPN’s most distributed products. The outcome offers pragmatic insights for KPN to slow primary CRM demand, aligning with the EU Critical Raw Materials Act and the company’s own sustainability objectives to achieve net-zero emissions in the value chain by 2040. Of the circular practices applied to an internet modem as use case, reuse shows the highest potential: compared to the total primary production and transport, the total emission reduction through reuse could amount to roughly 0.814% of emissions in the Dutch communications sector over the y to y+14 period. From a materials perspective, this research identified fifteen CRMs in the product under study. For these materials, reuse and recycling could prevent the need for 624 kg of CRMs on the printed circuit board. Including aluminium from the heatsink, material savings increase to a total of 241 tonnes, which equates to a Global Warming Potential (GWP) impact score prevention of up to 83.5% over the device’s total material production. Herein, mainly recycling has some limitations as KPN only applies open-loop recycling to a limited set of CRMs.
Furthermore, the study evaluates the potential of future circular strategies, such as improved waste management, product lifetime extension, and increased CRM recycling. These scenarios suggest that additional material savings could reach up to 10.7 tonnes, with an additional GWP
impact score prevention of around 3.89%. Increasing total GWP prevention from 83.5% to 87.4%. However, as this study uses a single product as use case, scaling this study’s approach across a broader range of telecommunication or other similar products is recommended to confirm whether substantial company- or sector-wide impact can be identified. In addition, this study recommends to also explore further possibilities to increase circularity; such as advancing on the R-ladder through refusing, rethinking and reducing the use of CRMs and critically assess how EU recycling targets could still be met within the limited remaining time.
Finally, this study contributes to the scientific debate by exploring the underexamined area of CRM flows in telecom equipment through circular strategies. By taking an industrial ecology (IE) perspective, it applies a systems approach to position KPN’s supply chain within its wider
environmental context, offering both practical implications and theoretical insights.

The transition to electric vehicles (EVs) is crucial for decarbonization, yet it has intensified the demand for critical raw materials (CRMs) like neodymium (Nd), essential for Neodymium-Iron-Boron (NdFeB) magnets used in EV traction motors. This study explores the integration of ecodesign principles into the lifecycle management of EV traction motors, with a focus on remanufacturing as a circular recovery strategy for NdFeB magnets. While recycling has been the predominant recovery strategy, this study explores the potential of remanufacturing as a complementary approach to retain embedded material value and extend traction motor lifespans.
A mixed-method approach was employed, integrating Material Flow Analysis (MFA) to map Nd flows within the EU’s EV sector, a literature review and semi-structured expert interviews to identify barriers and enablers. Key findings indicate that remanufacturing can reduce Nd losses more effectively than recycling, yet its adoption is hindered by design limitations, weak reverse logistics, and lack of economic incentives.
The study emphasizes the need for systemic transformations in EoL tracking, reverse logistics, and scalable remanufacturing infrastructure. While remanufacturing presents a viable pathway for CRM conservation, its feasibility depends on technological advancements, policy support, and industry collaboration. Future research should explore alternative motor designs, material substitution, and hybrid recovery models to further enhance circularity.

In response to calls for fundamental transformation of the economy, the idea of a circular economy has emerged as a promising direction. However, in practice, this idea is still commonly understood through conceptual lenses that reflect the logic of linear and mechanistic systems. This study explores the role of conceptual metaphors in circular economy discourse, arguing that the metaphors that are used to understand the economy significantly influence the kind of solutions that one can imagine and value. This research investigates the potential of the forest metaphor to support alternative ways of conceptualising the circular economy.

The first part of this study was aimed towards the identification of current dominant metaphors in circular economy discourse. It found that the machine metaphor was the most dominant metaphor. This was followed by competitive metaphors (sports and war), the journey metaphor, and, to a limited extent, ecological metaphors. The textual analysis showed that the current academic discourse predominantly:

(1) Makes sense of a circular economy in a mechanistic way, as the sum of resource inputs and outputs.
(2) Sees the relationships between businesses in a circular economy as competitive.
(3) Makes sense of change towards a circular economy as something that happens gradually and step-by-step.

The three most dominant metaphors are also dominant in current linear economy discourse and therefore reinforce similar patterns of thought. The ecological metaphor occurred less and was identified as a potentially interesting new line of enquiry, conceptualising nonlinear, complex and dynamic features, unlike the more dominant metaphors. This led to the main research question of this thesis:

How can ecology-inspired metaphors enrich circular economy discourse?

The second part of the research investigated the implications of using an ecology-based metaphor - specifically, the forest metaphor - to support conceptual development in circular economy learning. A case study was conducted on a postgraduate workshop, where participants engaged with the forest metaphor to explore circular business. Learners found the metaphor enriching, particularly in relation to ideas that incorporate the interconnectedness of businesses and the cooperation between different entities in the economy. However, many of the insights generated were general in nature and lacked specificity.

To further the exploration, a subdomain of the metaphor was explored in more detail: the technosphere as fruit from a tree. The technosphere refers to products, components and materials that are part of the human-made and managed realm, unlike biological nutrients. Through this study, products, components, and materials were understood as fruit from a tree. Unlike the machine metaphor, which tends to frame the economy as a closed and controllable system, this metaphor suggested more open flows of resources and information. The metaphor also allows social and environmental dimensions of a circular economy to be woven together more tightly in ideas and solutions.

In the third part of the study, a learning tool was developed to support the application of the forest metaphor to circular economy education. Eighteen subdomains of the forest metaphor were identified through interviews, each relating to one of three overarching themes: wholeness of the forest, the importance of relationships, and the response to change. These subdomains were reviewed by circular economy experts, who identified potential areas of application within existing circular economy discourse. Their input informed the development of a learning tool titled Ecological Design Thinking for a Circular Economy.

The fourth and final part of the study evaluated this tool through a comparative case study. A second workshop was conducted, similar in format to that of part two, but this time including the learning tool. Participant responses and workshop outcomes were compared with those from the earlier workshop. The findings suggest that the use of the tool contributed to more detailed and concrete ideas and that learners considered the engagement with the tool more enriching.

This thesis demonstrates the potential of the forest metaphor as an ecological metaphor for circular economy discourse. This metaphor prompts a reflection on the competitive nature of business and intellectual property rights and suggests ideas in line with more collaborative, decentralised and open approaches in business. In a generative way, the metaphor allows participants to focus more on community-led and place-based approaches to innovation, which allows businesses to tune into the local context surrounding their supply chain and business model, considering both social and environmental dimensions simultaneously.
Ultimately, this research reinforces that metaphors are not merely the decoration of language but can also be a learning tool. This can be used in a reflexive way, by challenging previously unquestioned assumptions, or in a generative way, by allowing new ways of thinking and developing novel solutions.

This thesis looks at the role that Circular Business Models (CBM) play in the development of a Circular Economy (CE) strategy in the aerospace sector. Currently, a transition from a traditional, linear economy to a CE is promoted by the EU and national governments. This thesis contributes to solving the many managerial issues or barriers when making that transition. Using literature review and semi-structured interviews, this case study on Airbus Netherlands discovered that the term CE is badly defined. This causes confusion and misunderstandings when discussing the concept of a CE. Therefore, properly defining a CE should be the foundation of developing a CE strategy. When analyzing the current CBM frameworks, the most well-known are the ReSOLVE and loops framework. The results further indicate that important barriers regarding the implementation of CBMs are technological and monetary challenges. On the other hand, implementing CBMs can have a positive effect on the reputation of the company and increase the chance of sustaining a supply chain. The best CBM strategies involve both a short- and long-term plan that focuses on where the aerospace sector, and Airbus Netherlands specifically can make the most changes like changing designs, swapping materials for less environmentally damaging ones and increase the recyclability of components. The interviews confirm issues found in the literature regarding the definitions and the barriers to implementing CBMs. In conclusion, it is evident that only by the combination of factors like regulations, proper definitions, internal motivation, financial feasibilities and technological developments, CBMs will be able to play a successful role in the developing of a CE strategy for the aerospace sector.

This research explores the intersection between circular economy strategies, critical raw materials (CRMs) and the defence sector, especially focusing on Neodymium-Iron-Boron (NdFeB) magnets. The significance of CRMs in modern defence applications and the associated risks of geopolitical and supply chain disruptions underscore the necessity for a secure supply. Circular strategies are crucial not only for securing a stable supply of CRMs but also for their potential to significantly reduce environmental impacts. This study aims to determine the effectiveness of various circular strategies in securing a stable supply of CRMs, thereby enhancing national security and promoting environmental sustainability. To address the research question, a mixed-methods approach was employed. Secondary data collection involved a review of scientific and grey literature, while primary data was obtained through interviews with experts. The conceptual framework was based on the 9R framework of circular strategies, chosen for its comprehensive coverage of all value retention options, from smarter product use and manufacturing, and lifespan-extending practices to the useful application of materials. This framework was adapted to the context of CRMs. The analysis was conducted using the backcasting method to develop strategic pathways for implementation. From the results, it is clear that NdFeB magnets are crucial to the defence sector due to their exceptional magnetic properties. This makes them indispensable in various defence applications, such as in motors, sensors, and communication devices. The reliance on CRMs like neodymium and dysprosium for the production of NdFeB magnets poses a significant risk due to their limited supply and geopolitical concentration. The study identified effective circular strategies on all 10 levels of value retention. This includes modular design, which facilitates easier disassembly and reuse, and advanced recycling techniques like hydrogen decrepitation, which efficiently reclaims materials. These strategies are already being implemented in the civil sector and can be adapted for defence applications to enhance sustainability and resource efficiency. To implement the circular strategies in the defence sector, barriers and enablers are highlighted on four levels: cultural, regulatory, market and technological challenges. Culturally, the defence sector has a somewhat conservative approach in which operational effectiveness is considered most important. Awareness about sustainability and CRMs can be created through programs, training and role modelling. Secondly, the defence sector is heavily regulated with stringent standards for performance and safety. Therefore, policies are important to ensure that circular practices comply with existing standards and incentives should be created. On the market level, commercial considerations are said to be the hardest challenges which should be taken care of in procurement processes. Lastly, adopting circular strategies involves technological innovations for which investments and development are crucial. Collaboration among various stakeholders is essential to the implementation. A detailed implementation plan is provided including measures to overcome the barriers alongside an indication of time. The research concludes that implementing circular strategies on NdFeB magnets within the defence should be improved as many more benefits can be gained from further implementation especially with regards to lowering dependence on CRMs. By adopting these strategies, the defence sector can not only secure a more reliable supply of critical materials but also contribute to broader sustainability goals. The circular strategies could be tailored to fit specifically into the defence sector by addressing unique challenges and leveraging opportunities.

Components of novel propulsion systems in electric aviation contain materials defined as critical by the European Union: electric motors contain Rare Earth Elements neodymium and dysprosium, and state-of-the-art batteries materials like lithium and cobalt. Such critical raw materials have high supply risks but are crucial for the economy. The demand of all these materials is forecasted to increase drastically in the coming years, which means that the rate of supply might no longer suffice to fill the demand. Circular economy principles have been suggested as a solution. Materials recovered from end-of-life components can secure supplies and reduce the environmental impact of products.

In this research, the implementation of circular economy approaches to address critical raw material demand in electric aviation is studied. According to the developed models, the material demand is negligible in comparison to other industries until 2050. However, as the electric aircraft technologies are still in development, there is a lot of uncertainty around the demand.

Beyond 2050, components will start reaching their end-of-life stage. In this case, a circular strategy considered feasible for electric motors is remanufacturing. After the Rare Earth Element magnets in the motors become obsolete, they can be recycled to recover the critical raw materials. Both hydrogen decrepitation and a combination of hydro- and pyrometallurgical processes can be used to regain materials for magnets in aviation or other applications.

Although circular economy strategies will not be able to significantly reduce the primary material demand in electric aviation by 2050, these can still lower the environmental impacts from production. Additionally, well-established circular practices could address the material demand more substantially in the future, after 2050, if electric technologies are more widely adopted then.

European climate goals to limit global warming to 1.5 degrees Celcius are unachievable in their current form because current green energy technologies needed for the energy transition rely too much on critical raw materials (CRMs). This thesis sought to design something that reduces the negative impact living has on the climate while making living less reliant on critical raw materials. Literature research showed that in the context of buildings, space heating and water heating are the biggest uses of energy in Europe. CRMs are found in many different products in homes, but primarily in electronics. This includes energy generation technologies such as solar panels, energy storage technologies such as batteries, entertainment technologies such as computers, but also other technologies such as boilers, pumps, ventilators and sensors. My research found that the link between human needs and current technologies in homes is a diverse and complicated one. To reduce our energy and CRM use in the built environment, a shift in the consumer’s mindset and a redesign of our technologies are needed. Tiny houses are a great inspiration and show that we can live comfortably with less energy and materials. This thesis looked at tiny houses as a springboard and example of how we can live more consciously and from a mindset of scarcity and balance instead of abundance. As a result, I designed and recorded a podcast that can discuss the complexity of the climate crisis while addressing the complicated human needs behind current CRM-dependent technologies. This podcast hopes to contribute to shifting the mindset and lifestyle of the listener to a more sustainable one.

The mitigation of climate change and the transition to a more sustainable and circular use of resources are two of the largest challenges of our time. To this end, the European Commission proposed the Net Zero Industry Act (NZIA) and Critical Raw Materials Act (CRMA) in March 2023 as further pillars to its Green Deal. While the NZIA focuses on establishing supply chains for net-zero technologies, the CRMA aims to maintain access to the necessary materials. However, these so-called Critical Raw Materials (CRMs), are not only required for net-zero technologies but also for numerous other applications. To ensure their growing demand can be met more sustainably, the European Commission CRMA proposal states that 15% of total CRM consumption in the EU must be satisfied through recycled materials by 2030. In response to the Commission’s proposal and as part of the legislative process, the European Council proposed a more ambitious target of 20% of demand to be satisfied through secondary materials. The European Parliament’s proposal takes a slightly different approach in that it suggests a 45% target for recycling all waste streams, rather than focusing on a set share of consumption.
Given the current dynamic nature of the legislative process, no publicly available literature exploring the extent to which the three proposals can contribute to meeting CRM demand more sustainably could be identified. Hence, the objective of this thesis is to quantify and analyze the implications of each recycling target, leading to the following research question: “How do the Critical Raw Materials Act recycling targets proposed by the European Commission, Council and Parliament compare in their contribution to meeting future demand more sustainably?”. To address this question, a case study on closed-loop neodymium recycling of NdFeB magnets in onshore and offshore wind turbines in Germany between 1989 and 2045 is performed. To map past and expected future neodymium stocks and flows, a dynamic material flow analysis (dMFA) is used. Building on a business-as-usual model without any recycling, explorative scenarios are developed reflecting each of the three CRMA proposals for recycling.
The results reveal that under the expected flow dynamics, the achievement and effectiveness of the targets depends on the time period considered. Because neodymium demand is expected to increase significantly over the upcoming decade, the Parliament’s targets are the most realistic until 2030, given that they are defined relative to actual waste streams. In contrast, achieving the Commission’s and Council’s consumption-based targets is comparably unrealistic, due to the fact that not enough waste streams will be available to satisfy 15 or even 20% of the rapidly growing demand. Extrapolating the targets of the Commission and Council beyond 2030, shows that they are achievable from around mid-2030 onwards. Regardless of the scenario, recycling rates need to increase significantly and rapidly. To meet the Commission’s and Council’s targets in particular, recycling rates of up to 100% until 2035 must be realized. Compared to current recycling rates of below 1%, this appears highly ambitious.
Policy makers are advised to establish targets beyond 2030 and to support relevant stakeholders in creating a recycling infrastructure, both financially and through favorable framework conditions. Future research should explore whether the specific trends observed in this case study also apply to other strategic applications and materials. Moreover, research on how product-life extensions could contribute to decreasing demand for primary materials in the short- to medium-run should be conducted.

Rapid urbanization and a growing world population has exerted unsustainable pressures on the environment, exacerbating climate change through unrestrained material usage and greenhouse gas (GHG) emissions. Since the turn of the century, transitioning to a circular economy (CE) has been seen by policy makers as a potential solution for resource scarcity and climate mitigation. Cities, which possess a high density of human activities, material stock, and waste production, are major contributors to emissions. This is especially true due to the concentration of construction activities in cities – the industry is responsible for 38% of CO2 emissions and 40% energy consumption globally. On the other hand, cities can also facilitate the implementation of circular strategies, thanks to increasing availability of data on space, people, and materials in cities. While the importance of cities for the circular transition is recognized in literature, earlier studies and policy documents on “circular cities” focus on urban governance strategies. Scholars have therefore called for a deeper understanding of the spatial aspects of CE since the late 2010s, engendering the recent integration of spatial disciplines, such as urban planning, regional economics, and geography, into the study of CE. Moreover, the increasing availability of spatial data, especially on the location of material stocks and flows, provides an unprecedented opportunity to develop a data-driven understanding of where, and how far, materials should travel in a CE. This research therefore asks the question, “what determines the locations and scales of closing material loops in a circular economy?” The question was answered in 5 chapters (chs. 3-7), using both quantitative and qualitative spatial analysis methods, as well as present- and future-oriented perspectives. The research scope moves from general to specific, with earlier chapters (chs. 3-6) analysing 10 material types for the whole country of the Netherlands, and later chapters (chs. 6-7) focusing on construction materials in the city of Amsterdam and its surrounding region. Two novel data sources were used throughout the research. Waste statistics from the Dutch National Waste Registry provided current locations of waste reuse; and a prediction dataset from the Dutch Environmental Assessment Agency provided locations for future supply for construction waste and future demand for construction materials. In chapter 3, a theoretical foundation for understanding locations and scales for closing material loops was constructed by identifying the drivers, barriers, and limitations of circular urban manufacturing - processes that produce goods using local secondary resources. By conducting a literature review and interviewing experts, it was found that there were several caveats to closing material loops at a local scale. Factors that determine the locations of circular urban manufacturers were identified from three perspectives: space, people, and flow. In chapter 4, the factors affecting locations of waste reuse in the Netherlands were identified using spatial correlation. The previously identified space, people, and flow factors were translated into quantitative spatial factors that could affect the location of waste reuse. Correlations were found for flow and space-related factors, but not for people-related factors, which suggests that actors within the waste-to-resource supply chain tend to attract each other and cluster together to form agglomerations, and that locations of waste reuse are not related to attributes of the local population, such as local income, skills, or education. In chapter 5, the location and scale of waste reuse clusters in the Netherlands were then identified using spatial statistical methods. This answered the main research question from a spatial econometric perspective, identifying industrial clusters for closing material loops. It was found that all the studied materials except for glass and textiles formed statistically significant spatial clusters. To determine the scale of spatial clustering, the grid cell sizes for data aggregation were varied, to find the cell size that had the strongest spatial clustering. The best fit cell size is ~7 km for materials associated with construction and agricultural industries, and ~20–25 km for plastic and metals. In chapter 6, to answer the question from a spatial planning perspective, spatial parameters were identified for circular construction hubs - facilities that close material loops by collecting, storing, and redistributing demolition waste as secondary construction materials. Using the Netherlands as a case study, spatial parameters were extracted from two sources: Dutch governmental policy documents, and interviews with companies operating circular hubs. Four types of circular construction hubs were identified: urban mining hubs, industry hubs, local material banks, and craft centers. The spatial requirements for the four hub types were translated into a list of spatial parameters and analysis methods required to identify future locations - site selection, spatial clustering, and facility location. Finally, in chapter 7, spatial optimization was used to identify the optimal scale and location for circular timber hubs in Amsterdam and its surrounding region, answering the main research question from the perspectives of industrial ecology and logistics. The optimal scale was defined as a scale that is most cost effective, minimizing costs and maximizing emissions reductions through timber reuse. The optimal number of hubs for the study area was 29, with an average service radius of 3 km. The cost effectiveness was affected mostly by transportation and storage costs, while emissions savings had minimal effect. As an overall conclusion, five tensions were identified for determining locations and scales for closing material loops, because of the diverse and sometimes misaligned spatial perspectives. The first three tensions are conceptual, addressing contrasting perspectives for defining closing material loops - as urban manufacturing or urban mining; for their locations - as clusters or hubs; and for the factors that affect locations and scales - as spaces, people, or materials. The final two tensions are methodological, addressing contrasting approaches to time - looking at the present or the future; and to methods - quantitative or qualitative.

The EU has set out to reduce negative impacts from electricity generation on the environment, human health and towards our dependence on fossil fuels. As the fastest growing renewable source of electricity, photovoltaics plays an important role in the energy transition. The manufacturing of photovoltaic modules requires materials classified as critical, making them prone to supply disruptions. Although these materials are essential to the EU economy, they are not sufficiently recovered at the end of a photovoltaic module’s life. An alternative intermediate solution could be to extend the lifespan of existing modules, to slow down demand for these materials in the future.
The aim of this study was to analyse the theoretical options and practical examples of product life extension strategies for photovoltaics. The R-Ladder was used as a guiding framework, which provided examples of life extension strategies. These include Reuse, Repair, Refurbishment, Remanufacture and Repurpose. Aspects for each of these strategies were analysed to find potential benefits and challenges related to four aspects: economics, environment, energy, and materials.
The approach of this study includes a literature review to identify the life extension strategies discussed specifically for photovoltaics in the context of the circular economy. This was followed by a multi-case study on practical applications of Reuse, Repair and Repurposing of photovoltaic modules. Findings from literature and the case study were further supplemented with the insights from six experts. These experts had diverse backgrounds in research, manufacturing, and procurement to offer a variety of insights and perspectives on life extension strategies for photovoltaics. Finally, two scenarios were created for possible life extension pathways for used photovoltaic modules to illustrate the potential impacts compared to a commonplace premature replacement scenario.
Economics and module performance are key factors in decision-making and acquisition of a photovoltaic system. Reuse offers a compelling alternative to current recycling capabilities but offers no sufficient business case. Repair may extend a module’s lifespan to continue the generation of renewable electricity but is only possible in cases of minor damage for which replacement parts are available. Refurbishment could restore more severe damage but is limited by economies of scale and the technical difficulties resulting from current photovoltaic module design. Remanufacturing has the potential to restore a solar cell’s original performance or even upgrade it using newer processing methods but suffers from the same design limitations as Refurbishment. Repurposing used modules can offer a pathway to extract the remaining capacity if it is implemented in a context where generation density is of no concern. Combined, these strategies could buy time to address the resource challenges amplified by the energy transition.

Urban areas are becoming more densely populated. More than 50% of the global population is already located in them. The Netherlands is among the countries with the highest population density. In 2017, 80% of its population was living in urban areas. It is expected that by 2050 the Netherlands will need between 300’000 and 1.6 million new homes. Construction & demolition (C&D) is characterized as a rsource-intensive industry and among the largest consumer of ntural resources. Urban areas account for 80% of global greenhouse gas emissions (GHG) and their infrastructures generate 50% of the total waste produced on earth. Additionally, the increased demand for housing and infrastructure will lead to increased demand for virgin materials and resources, and in turn more waste. From this perspective, the C&D industry will provide a significant contribution to sustainability and will be an important industry for the transition towards a circular economy (CE). The Netherlands has set very ambitious circularity targets for this industry. Specifically, the Government’s Real Estate Agency and Rijkswaterstraat must become fully circular by 2030. Circularity principles address the entire life-cycle of goods and resources, including
waste management practices. The overarching objective is to keep resources within closed loops and at their highest level of utility without losing their technical and economic integrity. As of now, 88% of waste generated yearly by the Dutch C&D industry is currently down-cycled for road backfilling purposes, 1-3% is currently reused or up-cycled for high-value practices and the remaining is incinerated.

The objective of this study is to identify the challenges that are characterizing recovery and reuse practices in the C&D industry in Zuid-Holland and make a preliminary assessment on whether Blockchain (through DLT and Smart contracts technologies) can be a suitable solution for addressing them. The methods
employed for conducting this study blend desk research with qualitative research (in the form of semistructured interviews) and a decision-making framework to assess the use of Blockchain technology.

The results indicate that the materials and construction elements to be considered more interesting concerning reuse and recovery are bricks, steel profiles and window/door frames. The decision-making process driving their reuse and recovery is company-specific and differs significantly across firms. In general, the data required for assessing the feasibility of reuse and recovery for construction elements are the material composition of new and old buildings, supply-and-demand specific information (volume and timing), technical specification and quality-related data as well as market prices. Challenges characterizing reuse and recovery practices are several. First, construction and demolition activities and asset management practices are asynchronous and separated by large time gaps. Material procurement starts significantly earlier than demolition activities and the process needs to be accurate and based on
reliable data. Data management practices are inconsistent and not harmonized among companies. Digital asset management tools (such as BIM), are employed by large companies only and their use on a national scale is neither harmonized nor compulsory. These aspect limit the economic feasibility of reuse and
recovery practices as the accuracy and reliability of data for driving decision-making is poor or nonexisting. Intra-project and intra-firm data sharing are therefore not possible. A Blockchain system which integrates smart contracts and distributed-ledger-technology (DLT) can partly address and tackle these
issues. To address them fully, however, Blockchain technology must be combined with an asset management tool like BIM for making the solution consistent and scalable at an industry level which in turn requires the implementation of national and industry-wide data management protocols and standards that would harmonize the collection, management and distribution of data across the C&D industry. The Netherlands, unlike other EU member states, has, at this point, no government-driven digitalization strategy in place and is rather opting for a market-driven transition.

The Circular Economy (CE) has emerged as an economic paradigm that could provide a pathway to sustainable development. The transition to a CE is a complex process requiring wide multi-level and multi-stakeholder engagement, which can be facilitated by appropriate policy interventions. As value retention processes in the CE require additional labour, the transition from a linear to a circular economy can be viewed as a transition from a capital-based economy to a labour economy. Consequently, a ‘circular tax shift’, based on an introduction of environmental taxation paired with a reduction of labour taxation, could be a powerful lever for public policy.

The aim of this research was to assess the effect of this tax shift on the financial feasibility of circularity in the construction sector. The main research question is: ‘What is the effect of a circular tax shift on the financial feasibility of circular construction, in relation to linear construction?’

To answer this question, a micro-economic analysis has been applied on two circular construction case studies: the ‘The Voice of Urban Nature’ and ‘Circuloco’ pavilions that were built at the Floriade World Expo 2022. A linear and circular variant have been developed for both case studies, for which a life cycle costing analysis has been conducted. A life cycle assessment has been applied to determine the environmental impacts, on the basis of which environmental taxation was applied under the taxation scenarios, which reflected varying levels of the circular tax shift.

The results show that under the current taxation system, the total life cycle costs for the circular variants are 2,0 - 2,7% higher than for the linear variants, though environmental impacts are lower by 38,7 - 52,7%. The effect of the tax shift is that the cost differences between the linear and circular variants decrease, and in two of the high level tax shift scenarios, the circular variant of the Circuloco pavilion becomes more financially feasible than the linear variant. Although the external validity is low, the results of the research imply that the suggested circular tax shift could create incentives to use secondary and biobased materials in construction.

The tax circular shift also implies many other effects, which are outside the scope of this research, but have been suggested as subjects for follow-up research.

Solar electric vehicles (SEVs) with integrated photovoltaic (PV) cells have the potential to decrease the related greenhouse gas emissions of regular BEV charging from the electricity grid. However, the environmental impacts and potential areas of improvement of such SEVs is yet under-explored. The aim of this study is to assess the environmental impacts of the vehicle integrated photovoltaics (VIPV) and to assess whether an SEV could act as a sustainable substitute for battery electric vehicles (BEVs) without VIPV. A life cycle assessment is performed to assess the environmental impacts from the cradle-to-grave life cycle, where an SEV is compared to a BEV without VIPV. Several environmental impact categories have been assessed: climate change (CC), acification (AC), energy resources (ER), fossil depletion (FD) and metal depletion (MD). A scenario LCA and sensitivity analysis have been performed to assess the influence of changing parameters on the CC impacts. The sensitivity analysis included different modelling decisions on vehicle efficiency, global horizontal irradiation and driving behavior. With a functional unit of 200,000 vehicle kilometers (vkm) the SEV resulted in lower CC impacts (compared to a BEV). Other impact categories show lower results for the SEV compared to the BEV after a use-phase of 200,000 vkm. The total functional unit of 200,000 vkm resulted in 3,300 kg CO2-eq less CC impacts for the SEV compared to the BEV without VIPV with similar vehicle characteristics. However, environmental impacts related to VIPV production were higher than the production of a regular vehicle exterior which means that the production phase of an SEV causes more impacts than the production of a BEV. In the reference case LCA, results showed that the break-even point of CC impacts between the SEV and BEV occurs at a distance driven of 79,000 vkm (6.1 years of operation in the Netherlands). Sensitivity analyses showed that the CC impacts are influenced by factors such as vehicle efficiency, global horizontal irradiation (GHI) and driving behavior. This study concludes that increasing vehicle efficiency seems to effectively decrease CC impacts similar to the effect that VIPV can have on a vehicle and improving vehicle efficiency can potentially even contribute more to use-phase CC impact savings than substituting a regular exterior by VIPV. Second, the GHI influences CC impacts of the SEV as the ratio of VIPV-electricity to grid-electricity depends on the amount of solar energy that is converted into electricity by the VIPV. Third, a driving behavior that enables the SEV to maximise its share of electricity powered by the VIPV showed the least CC impacts. Importantly, the lower CC impacts from SEVs compared to BEVs does not imply that SEVs are the most sustainable mode of transportation whereas there exist other less carbon-intensive alternatives (e.g. bikes and public transportation).

Digitalisation pressures the earth's resources, especially critical raw materials (CRMs). The CRMs, are functional materials that meet current challenges and future demands in information and communication technology (ICT). The extraction and processing of CRMs are highly concentrated, mainly outside the European Union (EU). The EU is dependent on import supply. Due to growing demand, an increase in primary CRM mining is expected shortly. Moreover, research showed that primary CRM mining significantly impacts human rights abuse. The increased CRM demand and supply can have an increased effect on human rights challenges. A greater focus is being placed in the EU on preventing and mitigating human rights violations in the global value chain. However, there is limited research in the telecommunication industry on managing human rights in the context of primary CRM supply. The growing demand in CRMs for telecommunication products and technologies highlights the importance of incorporating strategies to secure their business within the telecommunication sector. Therefore, this research aims to answer the following question: What strategies can telecommunication companies deploy in response to human rights challenges in primary critical raw materials supply? The methodology is mainly based on a qualitative approach. The research includes scientific and grey literature reviews, expert interviews, internal documents, and expert workshops. Research data is analysed using the framework on human rights in primary critical raw material supply development.

The research provides an overview of human rights in primary CRM supply. It shows the drivers and barriers for KPN in how to deal with this changing environment. The main focus is on human rights in the context of Conflict Mineral (CM) supply instead of the EU CRM list. Companies don’t have a fixed strategy in place to manage human rights challenges in primary CRM supply. Secondly, a case study is performed on cobalt extraction in the Democratic Republic of Congo (DRC). The general finding was that many human rights challenges occur in primary cobalt mining in the DRC. Various human rights challenges occur in artisanal small-scale mining (ASM) as well as in large-scale mining (LSM). Furthermore, among telecommunication companies, there are different levels of advancement in human rights due diligence practices in CRM supply. However KPN has an emergent strategy on the topic, the company is behind their peers in the level of advancement. At last, a strategy is developed for managing the human rights challenges in primary CRM supply. Experts validated the strategy.

The thesis concludes that becoming a responsible Mineral Initiative (RMI) member and implementing the OECD framework would be a decent start. The RMI provides tools and resources to advance on the topic. Having limited resources and capacity and dealing with complex mineral supply chains makes that a suitable option for KPN. In the medium term, KPN should explore additional actions, which should be the building blocks to advance on the topic and strengthen the company's position.

Further research could focus on exploring case studies CRMs in relation with human rights challenges, and understand the interaction of the system in depth. Moreover, develop schemes and guidelines for responsible supply of all minerals in LSM and ASM sector that are linked to human rights challenges. This is important in order to ensure that companies have a strategy in place. A strategy were human rights challenges are well managed and ensure responsible CRM supply.

BoorsmaRemanufacturing is one of the product recovery approaches in a circular economy. In the remanufacturing production process, used products are returned to their original product specifications. When compared to original manufacturing, remanufacturing results in lower raw material consumption and reduces carbon emissions. Despite having been operative for decades, across multiple industries, remanufacturing remains a niche company activity. The engineering knowledge on how to design products to improve the fit with the remanufacturing process is widely reported in academic literature. This thesis explores the role of strategic design in the context of remanufacturing and aims to promote a wider implementation of remanufacturing in industry. Strategic design determines the extent to which a product meets market needs, what its functionality should be, and whether it supports the company’s long-term objectives.

Critical Raw Materials (CRMs), materials with high economic importance and supply risk, are the key components of strategic sectors, including Information and Communications Technology (ICT). With foreseeable growth in CRMs demand, principles such as Circular Economy (CE) strategies are gaining attention as means to mitigate risks associated with CRMs. This study examines the effect each CE strategy has on CRMs in servers, via a case study of a Dutch telecommunications company. The study was conducted by collecting industry insights from 16 industry experts and performing a literature review.

Results show that out of 47 types of CRMs, at least 20 CRMs are contained in 4 sub-assemblies and 2 extension tools of a rack server. Among the sub-assemblies, the motherboard is found to contain the most diverse types of CRMs, while the HDD contains the largest amount of CRMs.

CE strategies were investigated in two ways, first by studying current strategies implemented by the company and its value chain partners, and by investigating advanced practices and strategies discussed in the literature. Results indicate that each CE strategy impacts the CRMs in sub-assemblies in different ways, while also having varied limitations in their potential. The result also shows that the current implementation of CE strategies does not always lead to the enhanced circularity of CRMs, as indicated in most of the CRMs being lost in current recycling practices. The degree of effect also differs depending on the strategy and sub-assembly. In the case of the motherboard, substantial potential to improve circularity was identified in the substitution method and advanced recycling strategy, with more CE strategy in need for Ba and P containing components. For HDDs, significant potential was observed in the functional substitution by SSDs and advanced HDD recycling technology. In addition, the strategies’ potential in mitigating the supply risk and environmental impact associated with CRMs was explored. While each strategy is seen to have the potential in reducing risk, its effectiveness depends on multiple factors and further case studies will be necessary to quantify it.

The results imply that enhancing the circularity of CRMs is a complex challenge where diverse interest from actors in the value chain is involved. For this reason, the study stresses the need for active collaboration among value chain partners and system-level support, to be able to design each CE strategy tailored for intended improvement in CRMs circularity. For the advancement of the topic, further studies are recommended, including the four goals of inventing secure ways for CRMs data sharing across the value chain, design for lifetime extension and CRMs recycling via collaboration between suppliers and downstream partners, finding economically viable business models for CRMs circularity, and assessing each CE strategy’s risk mitigation potential via specific case studies.

Businesses are being increasingly pressured to start making the transition from their current polluting economy towards a circular economy (CE) to pursuit a sustainable industry. Indicators for CE play a key role in this transition, enabling the measurement and control of this development. However, the scattered landscape of micro level CE indicators, which varies in purpose and scope, and their ambiguity in measuring environmental and social impact, complicates this transition. Circular consultants are being faced with these challenges when advising the right CE indicator to companies.
This study aims to provide CE consultants the tools to find an indicator that measures CE holistically and that fit their client’s profile. A literature review and interviews with 5 different circular consultants shows that many CE indicators are focused on material efficiency, leaving out aspects that are key for measuring environmental impact such as emissions and pollution. Additionally, social aspects are often not included in CE indicators even though the social dimension of CE is crucial for reaching a sustainable industry. At last, the literature review shows that CE indicators differ in characteristics such as purpose (such as learning or decision-making), their maturity in CE (from beginner to advanced), and data requirements.
Insights from the literature review and from the five interviews with different circular consultants, have led to the development of three tools: a checklist of sub-indicators for CE indicators to analyse their contribution to measuring environmental impact, a checklist of social indicators that are relevant for CE, and a framework to categorize CE indicators on six categories: measurement level, purposes of measuring, company’s maturity in CE, life cycle focus, ease of application and data requirements. The checklist for environmental impact and the categorization framework are applied to five CE indicators chosen from literature. The checklist provides an overview of sub-indicators present and missing in the CE indicators of analysis. Additionally, the sub-indicators in the checklist is translated into a questionnaire for a hypothetical company, to check its practicality. The framework shows that there are notable differences between the five CE indicators: in their purpose, life cycle focus, data requirements and ease of application.
Further work is required to investigate the tension between the CE indicator checklist for environmental impact and the ability of organizations to pick and choose CE indicators – which can be financially driven. Secondly, future case studies could help validate the effectiveness of the indicator checklist for environmental impact and the framework in assisting circular consultants in choosing a suitable and holistic CE indicator for a manufacturing company.