Transport poverty is a growing concern in the Netherlands, with affordability emerging as one of its most pressing and persistent dimensions. Rising transport costs and evolving urban infrastructure increasingly limit certain population groups' access to essential services such as employment, education, and healthcare. While shared mobility offers a potentially flexible and cost-efficient solution, policymakers still lack insight into how affordability transport poverty evolves over time and how such policies influence its dynamics.

This thesis quantitatively investigates if shared mobility can alleviate affordability transport poverty through a System Dynamics (SD) modeling approach, using selected demographic groups of the municipality of Almere as a case study. The model captures key feedback mechanisms linking employment income, transport costs, and travel behavior across distinct population segments, referred to as transport groups. It simulates how these groups adjust travel patterns based on available budgets, transport needs, and employment conditions. Core model components include travel budget thresholds, transport expenditures, and employment income. The main research question of this study is:

“What are the key dynamics of affordability transport poverty, and to what extent do shared mobility policies influence these dynamics across different demographic groups?”

To address this, two shared mobility policies were simulated:

- (Policy 1) Last-mile regional hubs: This policy provides regional shared mobility to extend the range of accessible travel.

- (Policy 2) Subsidized micro-hubs: This policy locally provides two days of free shared mobility options per week.

The analysis starts with a detailed base case simulation, focused on individuals in Almere with two defining characteristics: (1) they have either an income below social minimum or a sub-modal income, and (2) they either own a car or do not. These factors define four distinct transport groups used in the simulations.

Base case results show variation in vulnerability across these groups. Individuals with car access and with incomes below social minimum levels consistently exhibit the highest risk of falling into affordability transport poverty. In these groups, high transport costs eventually led to limited access to jobs, constrained travel budgets, and reduced salary, forming self-reinforcing feedback loops. This creates a poverty trap that further restricts social and economic mobility. By contrast, those who did not own a car and with a sub-modal income experienced less severe or no affordability issues, even under worsening economic conditions.

Both policies tested introduce improvements, with policy 1 being the most effective in increasing both income and reducing transport poverty levels. However, while somewhat effective, their impact is relatively modest in terms of increasing income or reducing severe transport poverty, and neither policy is sufficient to reverse the broader trends that contribute to affordability transport poverty. Yet still, the importance of moderate improvements in income must not be understated, especially for lower-income groups, who can have significant quality of life improvements with only modest amounts of increased income.

These results suggest that while shared mobility policies offer a degree of support, they are unlikely to resolve transport poverty when implemented in isolation. Affordability constraints are closely tied to broader socio-economic conditions, including housing, employment, and urban form. This highlights the importance of integrated approaches. Effectively addressing affordability transport poverty requires these measures to be complemented by strategies like targeting wages, job distribution, housing policy, and long-term transport costs.

Moreover, the results also underscore the importance of timing: early-stage interventions yield greater impact, especially before feedback loops fully entrench poverty. Delayed implementation reduces effectiveness, even for the same policy design.

The presented results do have some limitations. One of them is that this research adopted a general approach to shared mobility, without considering the associated implementation costs. It is important to acknowledge that alternative policies may be more financially viable. In that case, shared mobility could instead be applied in more targeted and specific contexts where other measures prove ineffective—one example being individuals who are highly car dependent but are not able to afford one.

Moreover, although the model simplifies real-world complexities, it offers a robust framework for understanding the core dynamics of affordability transport poverty. It contributes a novel application of SD modeling to this domain and provides insights for local policy. By uncovering the underlying feedback mechanisms and evaluating targeted interventions, this study lays the groundwork for future SD-based research and supports more equitable, data-driven policy design in cities like Almere and beyond.

As cities are densifying, low-car neighbourhoods are increasingly seen as a solution to reduce car dependency, improve public space, and encourage alternative mobility options. This study examines the impact of such a development by evaluating the mobility behaviour and perceptions of residents in Cartesius, a newly developed low-car neighbourhood in Utrecht. Using a revealed preference approach, this research analyses survey data (N=70) and qualitative insights from conversations with residents to explore the influence of residential self-selection on mobility adaptation. Findings indicate that even non-self-selected residents—those who did not actively choose a low-car environment—reduce car ownership and car use while increasing reliance on public transport and shared mobility. This suggests that well-designed low-car policies can influence travel behaviour beyond pre-existing preferences. Meaning that large-scale low-car policies could be viable for a broader population beyond those who actively choose this lifestyle.

Today, companies face increasing pressure to report their sustainability practices, particularly greenhouse gas emissions, due to new regulatory requirements such as the Corporate Sustainability Reporting Directive (CSRD) and European Sustainability Reporting Standards (ESRS). This thesis explores how Enterprise Resource Planning (ERP) systems, specifically SAP, can effectively support organizations in complying with emissions reporting under ESRS E1. An exploratory qualitative approach combining desk research, a detailed case analysis of SAP functionalities, and expert interviews was undertaken to investigate reporting requirements, data integration challenges, and best practices.

The research identified critical emission metrics required by ESRS E1 and evaluated SAP's capability to manage these metrics through its Sustainability Control Tower. Key challenges were found in the accurate and complete collection of emission data, particularly Scope 3 emissions. Furthermore, organizational and strategic obstacles, such as unclear responsibilities and viewing emissions reporting purely as compliance rather than a strategic advantage, were highlighted.

To address these challenges, the study proposes a structured 12-step roadmap, emphasizing data integration, clear internal governance, and strategic alignment of emissions reporting with broader business objectives. The roadmap facilitates accurate, compliant reporting while enhancing strategic decision-making capabilities. The thesis concludes that, although further validation of this roadmap in practice is necessary, ERP systems like SAP, when properly integrated, provide robust tools for effective emissions reporting and strategic sustainability management.

Hosting providers are essential for maintaining the security and reliability of digital services, but they continue to face challenges from malicious activities in their network, such as malware and phishing. The European Union’s Digital Services Act (DSA) was introduced to improve accountability and create a safer online environment, but its effectiveness in helping hosting providers mitigate abuse remains unclear. This study investigates whether compliance with the DSA has contributed to reducing malicious activity among Dutch hosting providers and examines the broader relationship between compliance levels and cybersecurity outcomes. This study evaluates the effectiveness of anti-abuse measures employed by Dutch hosting providers, with a focus on the role of the DSA in helping with compliance and reducing malicious activity. Specifically, it examines whether adherence to the DSA improves the ability of hosting providers to mitigate cyber threats, particularly in reducing the prevalence of malicious IP addresses. Using passive DNS data, the research examines changes in the prevalence of malicious IP addresses before and after the implementation of the DSA. Compliance levels were also analyzed to understand their correlation with malware percentages. The study employed statistical methods, including Interrupted Time Series (ITS) analysis and regression models, to evaluate trends and relationships between compliance and malicious activity. The findings indicate no statistically significant reduction in malicious IP activity following the implementation of the DSA, suggesting that compliance alone does not automatically translate into improved security outcomes. While the DSA strengthens transparency and procedural accountability, hosting providers continue to face operational challenges in implementing effective anti-abuse measures. Factors such as cybercriminal adaptation, enforcement inconsistencies, and resource constraints likely influence the weak correlation between compliance and actual abuse reduction. These results shows the need for a more holistic approach to cybersecurity regulation, combining technical advancements, industry collaboration, and proactive security enforcement alongside regulatory compliance. Evaluating the effectiveness of frameworks like the DSA is essential to ensuring that they not only establish compliance standards but also provide hosting providers with practical tools to enh The Dutch government aims to fully implement ERTMS (European Railway Traffic Management System) by 2050, with ETCS (European Train Control System) playing a crucial role. Currently, ETCS covers only 10% of the Dutch rail network, providing limited insight into train driver braking behavior. Differences between the current train control system (ATB) and ETCS systems cause deviations from the recommended speed curve, leading to inefficiencies in track utilization, increased wear and tear, and unrealistic capacity expectations. This research focuses on defining, visualizing and evaluating a balance between the ETCS requirements and the train driver behavior requirements, the comfort braking curve, within ETCS Level 2 parameters. As ETCS replaces ATB, it aims to enhance rail safety, capacity, and interoperability. However, train drivers currently operate under their own comfort preferences, which affects system performance. The goal is defining comfort and designing an optimal braking curve, compatible in the existing ETCS system based on the degree of comfort. And Investigate practical implications of the comfort braking curve, aligning train driver behavior, in relation to operational efficiency. The central research question is: What are the implications of implementing the comfort braking curve on capacity, wear and tear, safety, and driver experience? A literature review provided foundational knowledge on comfortable braking and driver behavior. The comfort braking curve is a smooth deceleration with minimal jerk ensuring smooth speed transitions, well-controlled braking and a balance between comfort, control, and safety. The comfort braking curve defines braking deceleration between 0.5 m/s2 - 0.6 m/s2 and a maximum jerk of 1.0 m/s3 to ensure a smooth ride. Practical observations show, for instance, that train drivers tend to coast 10% of their speed, avoid accelerating toward braking, and maintain margins to anticipate unforeseen situations. Expert interviews and analyses of train driver behavior in practice-, offered practical insights. This results in 6 factors and 6 scenarios that the train drivers described as discomfort. The comfort braking curve incorporates the anticipation strategies resulting from the 6 factors and 6 scenarios, so the comfort braking curve remains practical to be applied within operational constraints. Based on these insights and what the literature and practice say based on comfort, critical design parameters have been established. To do this, we examined how current braking curves are constructed and which parameters are important when designing the comfort braking curve, such as braking forces, velocities , and target distances. Simulations in FRISO validated the comfort braking curve under realistic conditions, analyzing its impact in terms of reliability, availability, maintenance, safety, health and environment. Results show the comfort braking curve fits within the timetable while maintaining robustness. Reduced energy consumption and power demands minimize equipment stress, leading to lower maintenance needs. Furthermore, the constant deceleration pattern improves driver experience by aligning with their natural behavior and enhancing predictability.ance online security and mitigate digital threats effectively.

Dutch ports face significant environmental challenges due to high greenhouse gas and air pollutant emissions from berthed ships engaged in essential operations. Entities like the Port of Rotterdam and research institutes produced emission inventories to gain insight into ports' environmental impact. 

However, existing emission inventories rely on fixed factors and overlook berthing duration and activities: they assume the same emission factors regardless of the operations performed by vessels. Thus hindering effective emission reduction strategies and infrastructure development. 

Consequently, the following research studies areas of improvement for the current emission calculation methods by including berthing time patterns. Then, it will apply this information to the Port of Rotterdam to test the new methodology.

The principal result that emerged from this work is that reality is far more complex than the most widely used models to represent it; luckily, the available data can still grasp this complexity. First, not all berthing events are equal, and the rarest ones still hold a considerable impact on the total berthing time. Additionally, the differences do not exist only as a matter of frequency and duration but also imply different energy requirements, as suggested by the interviewed parties. Consequently, a model based on a standard stop only reliably captures part of the behaviour of moored ships. Second, there is no universal relationship between standard industry size classes and time spent in port. Some ship types show a positive linear behaviour (the larger the ship, the longer the visit berthing time), while others show more complex relationships. Moreover, some fleet types belong to only a few classes; therefore, no size-related difference can be observed in the behaviour of berthed vessels. These considerations apply to metrics of volume (GT), maximum transportable weight (DWT), and also cargo capacity (TEU). Consequently, the size classes commonly used in the industry - which reflect the physical limits of channels, ports, and other waterways - might be insufficient to portray the in-port behaviour of all the fleet types. Third, most ships berth at a single location during a port visit, proving that the duration of a port visit could be the only way to identify different types of berthing events. Finally, even the interviews suggested that the system is much more complex than captured by the currently used models. The division by fleet type might be an oversimplification as the product transported and the ship type considerably influence the behaviour in port and energy consumption.

These results contrast with the emission calculation methodologies commonly used in literature and policy documents, indicating a widespread risk of policy and investment failure because partial data and oversimplified models of reality might have driven policy and economic decisions. Thus, institutions may have enacted regulations with potentially inefficient economic, environmental, and social returns. Consequently, improving the system's knowledge is essential for informed decision-making and risk minimization. This research has shown that this objective is not only reachable but could be achievable without exponentially increasing the required data.

When considering elderly individuals in the context of transportation, qualitative research seems to focus rather on mobility and the problems related than on the actual achievement of access. Additionally, certain bias and misconceptions about this diverse group still influences accessibility studies for elderly. This paper therefore explores the accessibility challenges faced by elderly individuals, particularly focusing on urban environments like Rotterdam. Interviews in a semi-structured format using the approach of microstories were conducted in May 2024 among elderly residents of Rotterdam, aged 67 and above. The Capability Approach was used as a framework to categorise the findings of these in-depth interviews. This study with its findings underlines the inherently heterogeneity of this group. Further it presents barriers as well as enablers of accessibility for this group and how this influences the way participants move and access activities within their city. These findings show how important it is to develop specific policies not just for ‘the elderly’ but for various sub-groups of them, as they show very different characteristics and abilities. Furthermore it challenges the typical view at accessibility, usually simplified by the land use and transportation system and time or distance-based thresholds, and whether these are really usable for this group.

Plastic pollution is a major global environmental issue, and its impact is even more pronounced in Small Island Developing States (SIDS) like Curaçao. These islands face unique challenges due to limited resources, heavy reliance on imports, and complex socio-cultural dynamics that complicate waste management. This study aimed to investigate plastic pollution in Curaçao by examining the local system, identifying challenges in policy design, and proposing effective strategies to mitigate environmental impact. The scientific knowledge gap lies in the limited understanding of how plastic pollution systems function in Small Island Developing States (SIDS) and the specific challenges they face when designing and implementing effective environmental policies.

The research focused on two objectives:

Understanding the dynamics of plastic pollution in Curaçao.Investigating the specific challenges in designing policies for plastic waste management.

Methodology:
A mixed-methods approach was used to achieve these objectives, combining stakeholder analysis, interviews, and observations. A framework was developed from existing literature to understand plastic pollution in Curaçao better. Stakeholder analysis identified key actors in managing plastic pollution, including government agencies, NGOs, recycling companies, and private sector participants. Interviews with these stakeholders, in which the plastic pollution and policy tool frameworks were discussed, provided insights into the plastic pollution system and policy implementation challenges. Field observations were conducted to assess waste management practices on the island, including illegal dumping and recycling efforts. Additionally, articles and reports on plastic pollution were reviewed to support other findings.

Key Findings:
This research on plastic pollution in Curaçao has yielded several critical insights:

Implementation Gaps: Despite the government’s ambitious goals to address plastic pollution, substantial gaps exist between these goals and their implementation. Limited resources, infrastructure constraints, street-level bureaucracy, and political volatility hinder effective policy enforcement.Cultural and Socio-Political Challenges: Curaçao’s unique cultural attitudes towards convenience and plastic consumption, along with political and economic instability, complicate efforts to manage plastic pollution. The short-term focus on economic and social issues often overshadows environmental concerns.Stakeholder Perspectives and Local Context: Stakeholders generally agree that the government should lead the charge against plastic pollution; however, there are concerns regarding the suitability and implementation of proposed solutions. A one-size-fits-all approach is impractical; tailored solutions considering Curaçao’s local context are essential.Framework for Action: The redesigned framework emphasizes rethinking plastic importation, reducing consumption, improving recycling rates, combating illegal disposal, and maintaining a clean island. This localized approach addresses the specific drivers of plastic pollution on the island.Barriers to Effective Policy: Key barriers include resource constraints, political challenges, lack of public awareness, and street-level bureaucracy. These factors collectively impede the development and implementation of effective environmental policies.

Contributions to Theory:
This research extends Alpizar’s framework to better fit the plastic pollution systems of Small Island Developing States (SIDS). It considers context-specific factors that influence these systems, enabling the identification of crucial battle arenas for effective intervention. Additionally, the study clarifies the role of street-level bureaucracy in enforcement and waste management within SIDS. It reveals how the limitations faced by frontline bureaucrats complicate the design and implementation of policies, emphasizing the need for practical solutions that account for these challenges. The findings underscore that effective policy requires a tailored approach; one-size-fits-all solutions for plastic pollution in SIDS are not viable. The cultural dynamics of these islands significantly shape attitudes and consumption patterns, indicating that any successful policy must integrate cultural considerations to resonate with local communities. Finally, the research highlights the impact of political volatility on environmental policy, demonstrating how instability can hinder the development and enforcement of effective plastic pollution strategies. This interplay between culture, politics, and environmental management calls for a nuanced understanding of local contexts in policy design.

Recommendations:
To effectively tackle plastic pollution in Curaçao, several key recommendations emerge:

Enhance Public Education and Expand the Plastic Ban: Launch comprehensive campaigns to promote environmental stewardship while broadening the ban on single-use plastics to include more items, ensuring accessible and sustainable alternatives.Implement a Plastic Deposit System: Introduce a deposit initiative that encourages the return of plastic containers, reducing waste and providing economic benefits.Improve Government Coordination and Support Enforcement: Develop a cohesive waste management strategy with clear roles for stakeholders, strengthen enforcement against illegal dumping, and provide resources and legal protections to front-line workers.Promote Recycling and External Partnerships: Invest in recycling infrastructure to encourage community participation and seek collaborations with NGOs and international entities for funding and expertise.Revise the Legislative Framework: Evaluate and strengthen existing waste management laws to ensure effective enforcement and compliance.

Limitations:
The research on plastic pollution in Curaçao highlights several limitations. The reliance on stakeholder interviews introduces subjectivity, potentially affecting the validity of the findings. The unique socio-cultural and political context of Curaçao limits the generalizability of results to other Small Island Developing States, necessitating localized solutions. The study’s focus on plastic pollution may overlook broader waste management issues. Recommendations are context-specific, emphasizing that a one-size-fits-all approach is impractical. Cultural attitudes towards convenience and plastic use complicate policy implementation, indicating that behavior change requires more than regulatory measures. Lastly, ongoing research is needed to assess long-term policy impacts and explore shared challenges among SIDS.

Future Research:
Much research is needed on plastic pollution, so I suggest starting with these topics:

Exploring a wider range of policies for plastic pollution in SIDS through stakeholder engagement.Conducting comparative studies among Small Island Developing States to identify shared challenges and solutions.Analyzing plastic pollution management evolution in developed countries to uncover effective strategies.Investigating consumer behavior regarding plastic use and disposal in Curaçao and other SIDS.Conducting longitudinal studies on the long-term impacts of policies like single-use plastic bans.

This study highlights the complexities of managing plastic pollution in Curaçao and underscores the need for a localized, culturally sensitive approach to policy design and implementation. While significant challenges remain, coordinated efforts involving government leadership, community engagement, and infrastructure improvements could lead to a more sustainable future. The insights offered a valuable framework for other SIDS facing similar environmental issues.

Situation
In the Netherlands, the deductible is an essential part of the healthcare system, designed to regulate healthcare usage and keep healthcare costs manageable. The current deductible is €385 per year, but there are growing concerns about the accessibility of care for vulnerable groups such as chronic healthcare users and care avoiders. These concerns have led to political debates and policy proposals to revise the deductible. The Dutch government is set to adjust the deductible in 2027, spreading the cost over multiple treatments, €50 per treatment with an annual maximum of €165. While these adjustments are intended to increase access to care, little is yet known about the broader social impact of such changes to the deductible.

Complication (Question)
The central question of this thesis is: “What are the social costs and benefits of the policy change in the Dutch deductible to €50 per treatment with an annual maximum of €165, compared to the current system, for the entire Dutch society over the period 2027-2070?”

Approach
To answer this question, a Social Cost-Benefit Analysis (SCBA) was conducted to evaluate the social impact of four policy options: elimination of the deductible, reduction to €50, reduction to €165, and the Spread scenario. The SCBA looked at both quantified and monetized impacts, including the benefits of accessibility through perceived cheaper care, increased costs of nominal premiums and income-dependent contributions through changes in healthcare usage, costs, and health benefits. The analysis period was from 2027 to 2070 and took into account uncertainty factors such as population growth and price elasticity of health care demand. Sensitivity and uncertainty analyses were conducted to evaluate the robustness of the results, and critical assessments were made of the assumptions underlying the model.

Results
The analysis showed that all four scenarios result in a negative Net Present Value (NPV), indicating that costs exceed benefits over the entire period of analysis. The Spread scenario resulted in a total NPV of -€194 billion, with an average annual NPV of -€4.41 billion with extremes values
-€4.92 billion and -€2.56 billion. These results suggest that the social costs, mainly caused by higher nominal premiums and income-related contributions, significantly exceed the expected benefits, such as reduced spending on deductibles and health benefits from improved access to care.

In addition, the results show that the intended financial threshold of the Spread scenario may not be effective in reducing healthcare usage. The analysis indicates that total costs for healthcare users under this scenario are often lower than under the current situation, even after multiple treatments. This implies that the lower cost per treatment may actually encourage rather than inhibit healthcare usage, leading to higher healthcare usage, longer waiting times for care, quality reduction in care, and higher costs to society.

At the individual level, we are talking about an average annual NPV of €275 per person. But this includes an increase in nominal premium and income dependent contribution of €452.90 plus the cost of the deductible. This will increase nominal premium more than the deductible will decrease. Society's solidarity will be greatly called upon, because the difference between payments for healthcare users and non-healthcare users will be significantly reduced, while the cost of the nominal premium will increase by 26%.

Next Steps
The study contained several assumptions that require further research to reduce uncertainties. It is recommended that follow-up research be conducted on detailed demographic analyses to better understand societal responses to policy. Furthermore, it is important to identify the long-term effects of early disease interventions to better estimate future care needs. In addition, it is crucial to reconsider the current policy proposal and conduct extensive research on its potential effects to ensure that policy goals are achieved without undermining solidarity.

The findings of this thesis contribute to the broader debate on the future of the Dutch healthcare system by emphasizing that policy choices around the deductible should not only be financially feasible, but also fairly and sustainably aligned with the fundamental values of solidarity and accessibility in healthcare.

The European Union has implemented Sustainable Aviation Fuel (SAF) blend mandates in its member states, starting for bio-SAF in 2025 and for synthetic SAF (e-SAF) in 2030. Various e-kerosene plant projects have taken off in the last years in Europe. However, due to the high investment costs and dependency on feedstock availability, no plant has reached final investment decision yet. In the Netherlands, two full scale e-kerosene plants have been announced to be build in the next decade. This paper estimates the net present value of one of these in the current market conditions of the Dutch aviation fuel market. For this, a real option tree model is created to represent the current risks, investment costs and market state in the Dutch geographical context. In addition, the impact of various policy measures are added to the model to create different policy scenarios. The objective of this paper is to find which policy scenario's yields a positive net present value for the analyzed PtL plant in the Netherlands.

The real option decision tree was composed in various steps. The model is based on an e-jet fuel plant based in the Netherlands with annual jet-fuel production capacity of 50,000 tonnes. The e-fuel mix contains 75% jet fuel, 12.5% diesel and 12.5% naphtha. This plant sources green hydrogen and CO2 externally, therefore does not require investment in direct air capture systems or an electrolyzer. First, the project stages and options were defined as in other energy projects. The length of each is approximated based on the status and expected deployment of current PtL e-kerosene plants. Next, the project investment and value was determined following the findings of previous works. The CAPEX was split up over the investment stages determined previously, and adjusted for inflation. Likewise, the OPEX found in various literature sources was inflation adjusted and averaged. The selling price is modeled to decrease at the same rate as the projected electrolyzer costs because of technology maturity. Market conditions were based on both fuel demand projections in the Netherlands and the European blend mandates for synthetic fuels until 2050. From this, two market condition scenarios were modeled. These were based on whether the modeled plant or its smaller competitor reaches market first. This makes a difference, as the fuel demand in the first years of operation is limited because of lower blend-mandates. Next, the abandon options were modeled by determining the salvage value. The salvage value was defined as the current replacement costs minus the depreciation. For this, the depreciation rates for each investment during both testing and operation were determined. After finding the values, the probability distribution for the options in the different project stages were determined. This was done using the probability ranges as defined in the classical risk matrix. The current and forecasted status of most prominent project and market risks were described, where after the risks were allocated to a probability range. The main value of each was used in the probability distribution. Lastly, the different policy incentives and scenarios were defined...

The aviation industry is undergoing rapid expansion, with an annual growth rate of 4.5% to 5%, positioning it as the fastest-growing mode of transportation worldwide. This growth, however, comes with significant environmental challenges, primarily due to the industry’s substantial contribution to greenhouse gas emissions. Currently, aviation accounts for 2.4% of global CO₂ emissions and 3% of the European Union’s total greenhouse emissions. If current trends persist, these figures are expected to rise dramatically, intensifying the urgency for the industry to align with international climate agreements, such as the United Nations Framework Convention on Climate Change (UNFCCC), by adopting eco-conscious strategies to reduce both CO₂ and non-CO₂ emissions. One way to achieve this is by reconsidering their airline networks. Airlines have traditionally focused on a cost-driven approach when optimizing their network structures, often sidelining environmental impacts. This approach, primarily motivated by market demand and operating costs, seeks to develop a network that minimizes expenses while maximizing profitability. However, with increasing awareness of the aviation industry’s significant contribution to climate change, it has become essential to consider whether airlines can achieve both cost-efficiency and environmental sustainability through strategic changes to their network design. As the aviation industry evolves, so do the expectations of its customers. In this service-oriented business, delivering high-quality service is a core competitive advantage. This advantage is closely linked to how well airlines listen to and act on customer feedback, particularly by integrating this to early stages of their operational decisions. Understanding passenger needs and expectations is crucial, as decisions made without considering these factors can reduce customer satisfaction. For instance, optimizing a network solely based on cost and climate impact might lead to less convenient flight schedules or routes, which could alienate passengers who prioritize certain departure times or direct routes.
Given these complexities, it is clear that airline network design must go beyond just cost and environ- mental considerations. Integrating the passenger perspective is crucial for developing a network that meets both operational goals and customer satisfaction. This leads to the need for a more holistic modeling approach that combines three key objectives: minimizing costs, reducing environmental impact, and accommodating passenger preferences. The proposed modeling approach in this research aims to address this challenge by developing an optimization model that integrates the economic goal of cost minimization with the environmental objective of reducing CO₂ emissions and the service-oriented goal of satisfying passenger preferences, particularly in terms of departure times. To support the development of this comprehensive optimization model, a thorough literature review was conducted to identify the specific criteria necessary for integrating environmental considerations and passenger preferences into airline network design. This review focused on understanding the environmental impacts of aviation, particularly CO₂ emissions, and the various strategies airlines can adopt to mitigate these effects. Additionally, it explored the importance of passenger preferences, with a particular emphasis on departure times, as a critical factor that can influence network design. Following the literature review, existing hub location models were analyzed to assess their applicability in this context. While traditional models are effective for optimizing cost-driven networks, they often fall short in addressing the additional layers of complexity introduced by environmental and passenger considerations. The research identified specific needs arising from these considerations, such as the need to account for CO₂ emissions linked to flight frequency and the importance of aligning flight schedules with passenger preferences. To address these gaps, the models were adapted and extended, incorporating these new objectives to create a more holistic approach to airline network design. The developed model was then tested using the well-known CAB dataset, a benchmark in hub location research. The testing phase included both single-objective optimization, where each of the three objectives (cost, environment, and passenger preferences) was optimized individually, and multi-objective optimization, where the model sought to balance all three objectives simultaneously. This approach allowed for a comprehensive evaluation of the model’s effectiveness in producing network designs that meet the diverse needs of airlines in today’s complex operational environment. This research provides a significant contribution to the field of airline network design by introducing an optimization model that harmonizes the often conflicting goals of economic efficiency, environmental sustainability, and passenger satisfaction. Through an integrative approach that accounts for the complexities of modern airline operations, this study advances the understanding of how these diverse objectives can be balanced within a single framework. The proposed model, tested using an established dataset, demonstrates its potential to influence both academic discourse and practical applications by offering a more nuanced understanding of the trade-offs inherent in network design. Moreover, this work highlights the broader social and scientific relevance of incorporating environmental and passenger-centric considerations into strategic planning, urging a shift towards more sustainable and responsive practices in the aviation industry.

Air transport, encompassing both passenger and cargo airplanes, is the second-largest energy consumer in the transportation sector, following road vehicles. The passenger sector has seen rapid expansion in recent years, with demand expected to double by 2040. Air cargo, which surged during the pandemic, is also experiencing increasing growth due to e-commerce and express logistics. Although frequent flying significantly boosts global connectivity and economic development, it also results in increasing carbon emissions.
Despite technological improvements making current aircraft 80% more fuel-efficient than those from the 1960s, aviation remains a significant environmental concern, responsible for around 4% of global CO2 emissions. The industry’s reliance on fossil-based jet fuel poses challenges for decarbonization, especially as carbon emissions at high altitudes have a substantial atmospheric impact.
Nevertheless, pressure to mitigate climate change is rising. The European Green Deal aims for climate neutrality by 2050, pushing the aviation industry towards net-zero carbon emissions.
Given that the current kerosene-based propulsion system is the primary source for carbon emissions, a radical change in propulsion technologies is urgently needed to achieve zero-carbon-emission flying by 2050. Among the technologies being explored, hydrogen propulsion is identified as a promising alternative for medium-range flights, making it particularly suitable for European air transport. Therefore, this master thesis focuses on the transition to hydrogen propulsion as a solution to significantly reduce aviation’s carbon footprint.
This study aims to understand how hydrogen propulsion can aid in decarbonizing air transport by identifying key factors influencing its adoption and exploring a strategic pathway for implementation.
The Multi-Level Perspective (MLP) framework served as the theoretical foundation for analyzing the transition, focusing on a technological niche, the socio-technical regime, and landscape pressures. This framework aids in the understanding that energy transitions often start in niches, highlighting hydrogen propulsion as a potential technological niche to significantly reduce carbon emissions in aviation.
Moreover, this study intended to investigate the idea of introducing hydrogen-powered technology in a specific aviation market niche to accelerate the transition. The air freight sector was examined for its potential to be perceived as a safer market for the implementation of a new technology compared to a direct application in passenger aviation. Additionally, the air cargo sector was found to be an underexplored market in the development of sustainable aviation technological solutions, resulting in a
significant knowledge gap in both scientific literature and industry applications. Following a qualitative approach, an extensive literature review and eleven interviews were conducted with aviation experts from academia, industry, and government. The interviews aimed to gather
insights on the drivers and barriers for hydrogen adoption in aviation, as well as on the potential of air cargo. The questions for the experts were formulated according to different levels of the MLP framework to drive the discussions. Firstly, at the niche level, technical aspects on hydrogen technology and air cargo were addressed. Secondly, the necessary conditions for hydrogen-regime transition were discussed across five different dimensions. Thirdly, global events in the aviation landscape that influence the adoption of hydrogen were specified. The wide variety of insights provided by the experts led to the classification of drivers and barriers into four main areas: technological, political, economic, and societal. Since hydrogen technology is still in the early experimental phase, a greater number of
technological challenges were identified compared to the other areas. Results showed diverse technological drivers including hydrogen’s clean production using renewable sources, its high gravimetric energy density, and its zero-carbon emissions during flight. However, technical barriers such as low volumetric energy density, the need for a complete overhaul of the existing aviation ecosystem, and challenges in hydrogen logistics and storage were noted. Politically, support for hydrogen adoption is driven by climate commitments and the potential for energy independence, but kerosene taxation and new regulations are needed. Economically, fluctuating fossil fuel prices and job creation are positive factors, but high initial R&D and infrastructure costs pose substantial challenges. Moreover, societal perception plays a crucial
role in the adoption of hydrogen technology. Public support is influenced by the environmental benefits of hydrogen-powered aviation, but safety concerns and a lack of understanding about hydrogen technology necessitate extensive public education and transparent communication efforts. Although the potential of hydrogen in aviation still needs to be proven, targeting the cargo sector is viewed as a smart move to demonstrate feasibility and build acceptance. Advantages of implementing hydrogen in air cargo include greater flexibility in technology integration due to simpler cabin systems and expertise in handling hazardous materials. Cargo aircraft can optimize tank placement without passenger accommodation constraints and benefit from centralized operations at key hubs, requiring less extensive infrastructure. Socially, it offers a low-exposure environment for technology testing, and economically, centralized hubs reduce costs, with potential market opportunities for ”green” military freighters. Nonetheless, the air freight sector may encounter difficulties in adopting hydrogen technology due to less public pressure for sustainable solutions, weaker economic incentives, and the challenge of justifying infrastructure costs, given the lower flight frequency and smaller market size compared to passenger aviation. This thesis is the first to explore the intersection of hydrogen-powered technology, socio-technical transitions, and the air cargo sector. It provides a comprehensive analysis by integrating technical, political, societal, and economic perspectives, highlighting the air cargo sector as a promising niche for early adoption. The theoretical framework offers insights into the challenges and opportunities in transitioning to hydrogen propulsion, with broader implications for other high-emission sectors seeking sustainable innovations. Based on the findings of this research, several recommendations were made to facilitate the transition to hydrogen-powered aircraft. Firstly, governments should implement policies and regulations that incentivize the adoption of hydrogen technology, such as kerosene taxation and CO2 restrictions on flights. Secondly, public education campaigns are necessary to improve societal perception and knowledge on hydrogen-powered aviation. Thirdly, collaboration with other industries working on hydrogen is essential to create a supportive ecosystem for hydrogen technology. Finally, focusing on the
air freight sector as a testing ground for hydrogen technology will help build acceptance and pave the way for its introduction into passenger aviation. Future research should focus on several key areas such as incorporating quantitative analyses to assess the economic viability and environmental impact of hydrogen-powered aircraft, expanding the scope of interviews to include diverse geographical regions, and integrating other research methods like case studies and surveys. Additionally, developing policy frameworks to support large-scale adoption and exploring other market niches, such as military and unmanned aircraft systems, are crucial for scaling hydrogen technology in aviation.

This thesis presents a life cycle assessment (LCA) comparing the environmental impacts of three electrolyzer technologies: Smart Alkaline Electrolyzer (SAE), Proton Exchange Membrane (PEM), and conventional Alkaline Electrolyzer (AEC). SAE, a novel technology distinguished by its modularity and scalability, offers seamless integration with renewable energy sources (RES). The study's scope, encompassing a cradle-to-gate analysis for 1 MW electrolyzers in Spain powered by solar PV, highlights the critical influence of electricity sources on environmental impacts. SAE outperformed PEM in seven of the eight assessed impact categories—climate change, terrestrial acidification, freshwater eutrophication, marine eutrophication, terrestrial ecotoxicity, ozone depletion, and photochemical oxidant formation potential (PCOF)—with a notable reduction in Global Warming Potential (GWP) at 7.39 kg CO₂ eq per kg H₂. Compared to AEC, SAE performed better in three impact categories and similar results in others. Key drivers of environmental impact were identified, with copper usage in power electronics being a significant contributor. The sensitivity analysis showed that 30% reduction in copper usage improved SAE's performance across 5 impact categories compared to AEC (climate change, acidification: terrestrial, eutrophication: marine, ozone depletion, PCOF: terrestrial ecosystems). The study identifies the key drivers of impacts within each electrolyzer and clearly delineates the subsystems of the BoP to make the comparison and analysis clear and to assess the overall impacts. The study also provides a structured and consistent inventory for the electrolyzers, enabling easy inclusion of other electrolyzer technologies, which several studies recommend.

Integrating bike-sharing programs with public transport enhances car-independent mobility, yet a comprehensive societal cost-benefit analysis of this integration remains scarce. This study addresses this gap by conducting an ex-post analysis of the OV-fiets program in the Netherlands, a station-based round-trip bike-sharing system designed to improve last-mile connectivity for train commuters. Spanning from 2004 to 2023, the analysis identifies 19 critical factors through an exhaustive literature review and expert consultations, with 14 factors subsequently quantified and monetized. The findings reveal a positive net present value (NPV) for the OV-fiets scheme, with benefit-cost ratios (BCRs) ranging from 1.1:1 to 2.4:1 and a median ratio of 1.5:1. Primary benefits include enhanced accessibility, reduced road congestion, and improved health outcomes, while significant costs are associated with initial investments and road safety impacts. This research underscores the considerable societal value of the OV-fiets program, warranting continued investment in the program and emphasizing the need for ongoing safety measures and infrastructure improvements. Additionally, it provides a robust framework for future assessments and improvements in similar urban contexts.

Global warming has increased societal awareness and the use of renewable energy, leading to the gradual replacement of fossil fuel vehicles with electric vehicles (EVs). To earn revenue, reduce electricity outages, increase grid stability, and incentivize the switch to EVs, parked EVs can discharge electricity into the grid through Vehicle-to-Grid (V2G) technology.

Transport hubs like airports are ideal for V2G projects due to their many parking spots and long parking durations. To determine financial feasibility, Cost-Benefit Analysis is a commonly used tool to compare two situations or cases. However, there are no CBA studies done on V2G in transport hubs like airports, presenting a significant literature gap.

This study hence analyzes the financial feasibility of a V2G project at Schiphol Airport using Financial Cost Benefit Analysis (FCBA) and risk analysis. The study aims to determine the conditions under which the project is commercially feasible by looking at the Benefit-to-Cost ratio, and at associated risks that might impact the success of such a project.

The analysis covers a seven-year period from January 2024 to December 2030 and is based on profit maximization theory. Key costs include V2G chargers and fees paid to EV owners, while benefits include revenue from electricity sales and carbon credits. The study compares a Base Case of expanding unidirectional EV charging with a Project Case of implementing bidirectional V2G charging. Results indicate that frequency regulation provides a Benefit-to-Cost ratio greater than one, making it the most viable method for generating revenue. Falling charger costs and a minimum V2G utilization rate are found to be crucial for the project’s financial feasibility.

The conducted risk analysis identifies potential challenges and propose mitigation strategies. The main risks include the potential unwillingness of grid operators to pay for FFR services and low adoption rates of V2G among EV users at Schiphol Airport. To mitigate these risks, the study suggests collaborative efforts with grid operators, awareness campaigns to educate EV users, and government support to incentivize V2G adoption. Given that the project's financial outlay is less than 1% of Schiphol Airport's annual infrastructure budget, the study concludes that the project is financially viable despite the identified risks.

Future research areas include using proprietary data from Schiphol Airport to enhance the accuracy of the study, particularly regarding parking and charging patterns of EVs. This research provides valuable insights into the V2G ecosystem as it is the first time a cost-benefit analysis is being conducted for a V2G project at a transport hub. It supports V2G’s application at transport hubs and paves the way for future real-life projects.

Aviation is one of the fastest-growing sources of greenhouse gas (GHG) emissions and continues to expand its emission footprint due to the growth of the global middle class and expanding international trade. Air cargo in particular is expected to grow rapidly over the next three decades at 4.1% globally, even outpacing expected growth rates for passenger air traffic. Abating emissions in aviation, however, is extremely challenging, making aviation a so-called hard-to-abate industry. Hard-to-abate industries typically have high energy consumption and limited options for decarbonization without substantial technological advancements or changes in industrial processes. Aviation is a hard-to-abate industry due to its strict operational requirements, limited potential for improvements to incumbent technologies, complex infrastructural requirements, a challenging market environment that leads to economic constraints, and the slow turnover of aircraft. Meanwhile, the importance of air cargo for the global economy is enormous because approximately 20% of international trade by value is transported by air while accounting for less than 1% by volume. Therefore, sensible decarbonisation strategies have to be outlined that preserve air cargo in its function as a catalyst for prosperity around the globe. To achieve the aviation industry’s net-zero emissions goal by 2050 the only feasible option for decarbonisation is the large-scale adoption of Sustainable Aviation Fuels (SAFs). SAF is a type of jet fuel that can be produced from biomass or electricity, reduces carbon emissions by up to 80% and has similar physical properties to conventional jet fuel, enabling its use in existing aircraft without modifications. Yet to date, adoption of SAF is extremely low at under 1% of total fuel consumption globally. The main barriers to large-scale diffusion of SAF are high production costs compared to conventional jet fuel and a lack of investments in new production facilities, leading to low availability of SAF. Nonetheless, policymakers and key industry actors are making tremendous efforts to drive the quick and reliable adoption of SAF. The USA, for instance, massively incentivises the domestic production of SAF through tax breaks as part of the ”Inflation Reduction Act”. Furthermore, the EU passed the ”RefuelEU Aviation Act” in the fall of 2023, mandating the increased use of SAF within the aviation sector. The act sets clear targets for SAF uptake, requiring that airlines use at least 2% SAF by 2025, increasing to 6% by 2030, and reaching 70% by 2050. Similarly, other countries like the UK, Norway, Singapore, Japan, Malaysia, Thailand, Turkey and Brazil have implemented or are expected to implement a SAF quota this decade. Moreover, large private corporations are dedicated to reducing their indirect emissions from their supply chain, referred to as scope 3 emissions. This commitment is driving significant demand for SAF, as businesses seek to lower their carbon footprint from transportation and logistics to meet stringent sustainability targets. While mandated or voluntary demand for SAF will inevitably increase the adoption of SAF in the near term, for the foreseeable future the price premium of SAF over conventional jet fuel will remain a major concern for all value chain members. Airlines, for example, are oftentimes unable to recoup the additional costs of SAF through the commercialisation of sustainable transportation products. Since cargo airlines are the focal link of the air cargo value chain, connecting the upstream segment, e.g. OEMs and airports, with the downstream segment, e.g. freight distributors, changes to one actor of the air cargo value chain will create follow-up effects on adjacent actors. Consequently, the current business models of all air cargo value chain members, including their respective revenue streams, value propositions and cost structures, are called into question. This leads to the following research question: How does the use of SAF impact companies’ business models across the air cargo industry value chain? To address the research question a two-pronged research approach was taken. Initially, a conceptual model was developed based on a modified version of the ”Business Model Canvas” by Osterwalder and Pigneur (2010) to dissect the rather abstract construct of a business model. This conceptual mode was then used to analyse the current business model of the most relevant air cargo value chain actors, e.g. aircraft manufacturers, airports, cargo airlines and freight distributors, and to hypothesise potenitial changes to these caused by the large-scale adoption of SAF. Subsequently, ten semi-structured interviews assessed industry experts’ perceptions on this topic to enrich the understanding of SAF’s impact on air cargo. The findings suggest that the impacts on investigated business models can be roughly divided into two groups. On the one hand aircraft manufacturers and airports are not directly affected by the adoption of SAF in air cargo. Therefore these actors function as facilitators and coordinators for the diffusion of SAF. Cargo airlines and freight distributors are expected to experience fundamental changes to their business model caused by SAF. These actors must quickly reevaluate their business model to align with the emerging sustainability standards and regulations. As mentioned above, aircraft manufacturers and airports are expected to experience negligible or minor impacts on their cost structures and revenue streams due to the adoption of SAF in air cargo. Airports currently do not own or operate fuelling facilities. This responsibility is outsourced to energy companies such as BP and Shell, which acquire multi-year concessions from airports to operate these facilities. Consequently, airports show little interest in investing in SAF production plants due to the associated risks, making additional revenues from SAF unlikely. Similarly, aircraft manufacturers do not anticipate significant revenue gains from producing aircraft with improved SAF blending certifications. This is primarily because OEMs are already operating at maximum production capacity and the industry’s focus is on producing as many new aircraft as possible to reduce emissions. Additionally, aircraft manufacturers will not experience changes to their cost structures, as existing technological knowledge can be leveraged without the need for new developments. This allows them to continue their operations without incurring extra costs related to SAF integration. Nonetheless, aircraft manufacturers’ and airports’ role as coordinators for the adoption of SAF requires changes to other building blocks of their respective business models such as partner networks and key activities to maintain business model consistency. For aircraft manufacturers, this means adding organizations involved in the production and certification of SAF to their partner network. Additionally, new key activities for aircraft manufacturers include orchestrating the scale-up of SAF production and facilitating and coordinating SAF adoption to avoid technological disruption. For airports, it involves positioning themselves strategically within the new SAF value chain to drive adoption advantageously. Additionally, airports need to rethink their customer relationships with airlines to create and sustain demand for SAF from airlines which will then attract investments in SAF infrastructure and production. Furthermore, SAF offers a unique opportunity for differentiation. Airports can use their well-established relationships with important stakeholders to advocate for SAF production in close proximity to the airport or analogue SAF transportation infrastructure. This step will enhance the airport’s value proposition by offering airlines the possibility to fuel large quantities of SAF. Aircraft manufacturers on the other hand can use higher SAF blending certification for their aircraft models to gain an advantage over competitors and improve their value proposition. Cargo airlines and freight distributors are expected to experience tremendous changes to their cost structure caused by consistently higher prices for SAF in the long term. This circumstance presumes higher revenue streams to maintain their business models’ financial viability. The ability to generate higher revenues is contingent upon the value proposition provided by cargo airlines and freight distributors. Therefore, the effective commercialization of sustainable transportation services will become a key activity for these companies. Promising approaches to the commercialisation of SAF include the ability for cargo owners to claim scope 3 emissions reductions based on the use of SAF, and the ability to offer SAF as part of a wider business case where sustainable transport is offered as an added value to the consumer purchasing a specific product. To conduct these measures the industry requires standardised carbon accounting rules to claim emissions reduction, a comprehensive approach to SAF certificate trading to track the flow of SAF and emissions across the value chain, and a reliable legal framework that allows companies to communicate the benefits of SAF to the consumer without the risk of being accused of greenwashing. Achieving this will require cargo airlines and freight distributors to expand their partner network to include new collaborators. For example, organizations that set standards for carbon accounting should be integrated. Additionally, developing a SAF certificate trading system with the necessary partners in the fuel supply chain is essential. Ultimately, these measures will significantly enhance the value proposition. Nonetheless, it has to be noted that not all cargo owners yet demonstrate a sufficient willingness to pay for sustainability. Therefore, close customer relationships and a comprehensive but concise communication of the benefits of SAF will become pivotal for cargo airlines and freight distributors. To identify lead customers for the commercialisation of SAF customer segmentation will be conducted along novel criteria. Examples of these are a cargo owner’s emphasis on emissions reduction (in this case a customer’s adherence to the SBT initiative is usually a good proxy), a fixation on high-margin industries that are able to pay a premium for SAF (e.g. the luxury goods or pharmaceuticals sector), and a focus on industries that are close to the consumer and are therefore able to communicate sustainability as an added value (e.g. the retail or apparel sector). Lastly, amid the significant uncertainty surrounding the adoption of emerging technologies like SAF, effective risk management will be pivotal. Especially demand, price, policy and technology risks require careful consideration, positioning effective risk management as a second key activity. Despite these changes, the early and decisive adoption of SAF by cargo airlines and freight distributors presents numerous opportunities. The complexity of SAF certificate trading and carbon accounting, among other aspects, means that the successful commercialization of SAF will be the result of a long learning process. To avoid falling behind, companies must set out today to capitalise on the rapidly growing market for sustainable transportation services. Furthermore, the decarbonisation of aviation through the use of SAF presents a unique opportunity to showcase that the aviation industry is able to address its problems effectively, creating social and political acceptance for future industry growth in the process. This thesis is the first study to investigate the intersection of SAF, business model transformation, and air cargo. Beyond its contribution to research, the results also have significant practical implications. The anticipated cost increases, coupled with the prevalent inability to recoup these additional expenses through the successful commercialization of sustainable transportation services, pose a substantial risk to the viability of cargo airlines’ and freight distributors’ business models. Mandated SAF quotas in the EU, which can lead to competitive distortions between airlines and freight distributors from different geographic regions, are a particular concern. The insights from this study can help companies navigate these emerging risks by identifying the areas of their business models most impacted. To address potential risks, companies must first be aware of their existence and pinpoint where they occur. Now that an awareness of the aforementioned potentially negative impacts is created, companies can carry out an as-is analysis of the relevant areas. Additionally, this study advocates for a shift in the conversation around SAF. Instead of viewing SAF as a cost burden, it suggests recognising the early adoption of SAF as an opportunity to gain valuable experience in the commercialization of sustainable transportation solutions, especially in light of growing public pressure for decarbonization. This opportunistic view on SAF can help to create and sustain company internal support for early investments in SAF. Furthermore, the study’s results highlight the importance of aircraft manufacturers and airports as facilitators for the adoption of SAF. This is contrary to the prevailing conviction that the actors can not shape the transition. Being aware of this will help aircraft manufacturer and airports to re-evaluate their corporate strategy, potentially strengthening their business models’ resilience and flexibility. In conclusion, the research reveals that the adoption of SAF significantly impacts the business models of companies across the air cargo industry value chain. Aircraft manufacturers and airports, playing coordinative roles, experience minimal direct effects on their cost structures and revenue streams. Instead, their contribution lies in facilitating the diffusion of SAF by coordinating between new and existing partners. In contrast, cargo airlines and freight distributors face substantial changes due to the higher costs associated with SAF. These companies must adapt their business models to effectively commercialise sustainable transportation services, which includes developing robust carbon accounting practices, SAF certificate trading systems and strong customer relationships focused on sustainability. The findings indicate that proactive adjustments to business models, focusing on the commercialization of sustainability to allocate the additional costs of SAF across the value chain, will be essential for cargo airlines and freight distributors to sustain financially viable and globally competitive business models. The study also emphasises the necessity for these actors to view SAF adoption as an opportunity rather than a burden, enabling them to gain valuable experience and lead in the sustainable air cargo market. This shift in perspective, combined with necessary strategic changes in partner networks and key activities, can help mitigate risks and leverage the growing demand for sustainable transportation. By addressing these challenges proactively, companies can position themselves advantageously in an increasingly environmentally conscious air cargo market.

This research evaluates the accessibility in industrial areas to the labour force by applying a spatio-temporal accessibility model in the IJmond region, located in The Netherlands. Industrial areas are crucial for regional economic activity, impacting employment opportunities for the labour force, especially those with lower incomes. This research aims to understand how the spatiotemporal configuration of industrial areas affects accessibility for different demographic groups and its implications for transport equity. The study shifts focus from job accessibility for workers to workforce accessibility from the employers' perspective, highlighting challenges faced by industrial areas regarding public transport. A gravity model is built to analyse spatiotemporal accessibility using socio-demographic data from CBS and geographic data from IBIS. Findings indicate significant disparities in non-spatiotemporal accessibility levels between car and public transit, with car accessibility generally higher. Focusing on spatio-temporal accessibility for transit has shown that levels decrease further during the night. Many industrial areas become 'unreachable' by public transit during nighttime hours with those that remain reachable, facing significantly longer travel times. In addition, it has been found that low-income workers tend to live closer to industrial areas and in higher concentrations compared to high-income workers. Recommendations include developing alternative transport solutions that will primarily support shift workers during nighttime, enhancing pedestrian and cycling routes, and utilizing more detailed neighbourhood-level data for future studies that aim to improve accessibility and gain more insights into equity in industrial areas.

Nature-based-solutions (NbS) are defined as strategies meeting societal challenges through the utilisation of natural features or processes which simultaneously provide biodiversity and human well-being benefits. NbS examples include vegetated foreshores or mangroves for coastal surge reduction, wetlands for water retention and/or quality improvement, and tree planting for urban heat mitigation. NbS are recognised as offering the potential for adaptation (and mitigation) to climate change while strengthening biosphere integrity and societal well-being effectively.

However, widespread implementation and realisation of NbS potential remain elusive. A significant factor contributing to this is the poor understanding of associated multi-functional trade-offs, leading the literature to urge for a systems approach to enhance this understanding. Multi-functionality concerns the three main impact dimensions of NbS: social, ecological and economic. As such, this research addresses the need for comprehensive assessment and understanding of multi-functional trade-offs associated with Nature-Based Solutions (NbS) for climate change adaptation, with a specific focus on deltaic regions, and aims to explore the applicability of a system dynamic modelling (SDM) approach in this context. To arrive at the main research objective, a mixed method approach grounded in the SDM methodology was adopted, which was applied on a deltaic case-study. Specifically, the study highlighted the complex social-ecological system of the Ebro Delta in Spain, where NbS are being considered for climate change adaptation.

Initially, an extensive literature review identified knowledge gaps related to the research objective, setting the stage for a heavily iterative exploration. This iterative approach was utilized to develop a guiding meta-model capable of capturing the multi-functional dynamics associated with NbS for climate change adaptation in deltaic regions, detail this meta-model for the case study, and apply this detailed meta-model to guide the quantitative SD modelling effort. As the object of inquiry, the case-study served to refine and illustrate the exploration, while yielding contextual insights benefiting local policy.

The results suggest that the SDM methodology is well-suited to assess the multi-functional trade-offs associated with NbS for climate change adaptation in deltaic regions. Three aspects of the methodology have been clarified: Firstly, the need for the application of the SDM methodology to this context has been strongly underscored. Secondly, the SDM methodology is able to comprehensively quantify multi-functional trade-offs, while maintaining versatility for different applications (i.e. contextual and/or case-specific) and facilitating communication and learning. Thirdly, the developed meta-model is suitable to facilitate a) problem exploration and b) guide a quantitative SD modelling effort. Furthermore, the findings illustrated that the trade-offs associated with NbS under climate change depend to a large extent on the existing social, economic, and ecological structure and associated values of the system where the interventions are intended to function. As such, it is argued that an extensive understanding of this structure and its behaviour (under changing conditions) is imperative if an accurate and comprehensive assessment of NbS impacts is desired. Moreover, in the context of regional-scale NbS, policy should be cautious of simplicity. Instead, it should embrace the inherent and systemic complexity of NbS, recognizing and leveraging the wide and multi-functional solution space that spans multiple disciplines and stakeholders