The maritime sector faces mounting pressure to decarbonise in alignment with global climate objectives and regional frameworks such as the EU Fit-for-55 package and the IMO net-zero targets. For fleet operators such as the Port of Rotterdam, which aims to reduce Scope 1 and 2 emissions by 90% in 2030 and sail emissions-free from 2035, this involves navigating complex trade-offs between sustainability, cost-efficiency, and operational readiness. This thesis investigates how the Port of Rotterdam can optimise its fleet renewal strategy to minimise total polluting emissions and transition costs while maintaining functional capacity.

To address this challenge, a hybrid decision-support framework was developed, combining multi -objective optimisation with multi-criteria decision analysis. The optimisation model produced Pareto optimal strategies, using the ε-constraint method, that balance lifecycle CO2 emissions, total cost of ownership, and local air pollution. Multi-criteria decision analysis, using TOPSIS, enabled inclusion of stakeholder preferences in the classification of different transition schedules under varying assumptions about fuel types, material choice, and production location. Scenario analyses were performed to assess the robustness of the combined framework against various economic outlooks and environmental choices, such as fuel type, hull material, and production location.

The results show that lifecycle emissions are largely shaped by design decisions such as material and energy source, whereas local pollutants are very sensitive to the replacement schedule. The total cost of ownership shows limited sensitivity to scheduling (1–2% variation), while battery production and dismantling emerge as the dominant drivers of greenhouse gas emissions and financial impact. The inclusion of CO2 emission depreciation significantly altered the schedules of optimal results, raising ethical and policy considerations. Certain vessel classes demonstrated robust scheduling behaviour, in various strategic choices and economic scenarios, identifying them as low regret alternatives. Other classes were more sensitive to changes in the strategic choices or stakeholder preferences.

The framework successfully supported trade-off navigation, revealing how rankings changed under varying stakeholder preferences and scenario assumptions. However, several simplifications remain. The decoupled class structure limited the ability to model shared infrastructure and battery packs. The cost structures did not reflect strategic procurement differences, and the lifecycle assessment focused solely on CO2-equivalent emissions, excluding other impact categories such as toxicity or resource depletion. These limitations suggest that future extensions should integrate infrastructure co-optimisation, procurement variation, and broader environmental metrics to fully capture the system-level implications
of fleet renewal.

This research contributes a replicable, stakeholder-aligned methodology for sustainable fleet transition planning. It provides the Port of Rotterdam with a transparent and data-driven tool to align its environmental commitments with long-term operational and financial viability, providing critical insights for fleet operators pursuing low-emission transitions.

Abstract─ Indonesia’s container port sector is economically vital but contributes significantly to national greenhouse gas (GHG) emissions. Emissions reduction planning remains fragmented, especially for small and medium-sized terminals. This study develops a standardized, scalable framework for quantifying emissions, forecasting trends, and assessing the cost-effectiveness of decarbonization measures across Indonesian container terminals. Using operational data from five terminals, large (TPS, BJTI, TTL), medium (Palembang), and small (Jambi), an activity-based inventory was built for Scope 1, 2, and 3 emissions. Future emissions were projected under business-as-usual (BAU) and mitigation scenarios, and five decarbonization strategies were evaluated using Marginal Abatement Cost Curve (MACC) analysis. In 2024, carbon intensity ranged from 20.1 to 34.2 kgCO₂e/TEU, with higher values driven by vessel hoteling and carbon-intensive grids rather than terminal size. Without intervention, emission intensity is projected to decrease by 20% and increasing up to 11% by 2050. Operational measures like layout optimization (as low as €0.1/tCO₂) and operator training (€7.3/tCO₂) offer immediate, low-cost reductions. Structural options such as onshore power supply (OPS) and equipment electrification yield larger abatement but are only cost-effective with a cleaner electricity grid. Solar PV offers moderate reductions and energy resilience, becoming viable at carbon prices above €40/t. Most structural measures are economically attractive between €0–50/t. The findings support a phased strategy: prioritize operational efficiency first, implement OPS and solar PV as the grid decarbonizes, and phase in electrification during asset renewal cycles to support sustainable port development.
Index Terms─ Container Port Decarbonization, CO2 Emissions, Marginal Abatement Cost Curve (MACC)

This research investigates the value of transport mode flexibility in OCCUS supply chains, particularly under uncertain CO2 supply during the early phases of CCUS development. This study aims to develop a strategic decision support model that quantifies the economic and environmental benefits of transport flexibility within the supply chain.
The literature review provides two key insights. First, it identifies the essential steps in the CO2 sup- ply chain: CO2 is captured onboard ships, temporarily stored onboard in solvent, and transported to onshore facilities for regeneration and liquefaction, after which the liquefied CO2 is transported to per- manent underground storage. Second, the review reveals that no comprehensive studies currently model the full OCCUS supply chain while incorporating uncertainty in CO2 supply. Consequently, no established approaches exist to address transport flexibility under such uncertainty within this context. However, real options analysis has been successfully applied in land-based CCUS projects to value in- vestment and operational flexibility under uncertainty. Building on this proven methodology, the present research adopts a real options approach to quantify the value of the option to switch between transport modes.

This research applies the developed real options model to a case study centered on the Port of Rotter- dam. The supply chain model follows the Value Maritime approach: CO2 is captured onboard ships, stored in CO2 -rich solvent and offloaded at the Maasvlakte terminal. Transport from the port to the re- generation and liquefaction facility is done with containerized trucks, with the option to switch to barges. Two barge types are considered: the smaller CEMT-IVa and the larger CEMT-Va or a combination of the two. The LCO2 is subsequently transported by truck to an underground storage site. The model evaluates scenarios under both a fixed average CO2 price (€136/t) and a variable CO2 price increasing over time based on market forecasts.

The results indicate that while the average CO2 price is insufficient to achieve economic viability at any time and outcome, incorporating the option to switch from truck to barge transport adds value if CO2 supply grows. The option to switch to the smaller CEMT-IVa (€630345) barge shows greater economic benefits compared to the larger CEMT-Va (€131555), mainly due to its better alignment with expected supply volumes during the early implementation phase. The combined switching option (€632010) only yields a marginal additional value, as the larger barge is only required at the highest and least probable supply scenario.

Under the variable CO2 price scenario, the truck-only strategy reaches a positive total value by 2031 with a 30% probability. Introducing the option to switch to the smaller CEMT-IVa barge accelerates this to 2029 with a 55% probability, reflecting earlier and more frequent switching. The larger CEMT-Va barge lags behind, with switching and positive value only occurring from 2030 onward and at a lower 11% probability, indicating less frequent and delayed use.

The break-even price for the truck-only transport strategy is €184.21/tCO2 . The inclusion of switch- ing options reduces this threshold across all configurations: the CEMT-IVa barge option achieves a 4.35% reduction to €176.19/tCO2 , while the CEMT-Va barge provides a modest 0.92% reduction to €182.52/tCO2 . The combined strategy yields the largest reduction of 4.36%, lowering the break-even price to €176.17/tCO2 .

Offshore construction vessels produce significant greenhouse gas (GHG) emissions, which led to the need to understand how operational decisions can mitigate their environmental impact. This thesis investigates the link between operational decision making and vessel emissions, focussing on Jumbo Maritime’s offshore installation projects. A mixed methods approach was adopted, which combined quantitative analysis of vessel operational data with qualitative insights from stakeholder interviews. Detailed analysis of daily progress reports, energy system models, and fuel consumption records allowed the quantification of emissions for each operational activity. Meanwhile, interviews with on- and offshore managers showed how factors such as contract requirements and project complexity influence decision-making in practice.
The results identify which activities drive the highest emissions and why. Dynamic positioning (DP) during offshore operations and transits emerged as the major contributor to fuel use and emissions, whereas periods at anchor or in port resulted in minimal fuel consumption. Unplanned downtime, especially waiting on weather and technical breakdowns, contributed substantially to emissions.
Crucially, the study found that certain operational strategies can noticeably reduce emissions without compromising project performance. Key recommendations include using anchoring instead of continuous DP whenever conditions allow, and implementing proactive maintenance programmes to minimise breakdowns and associated downtime. In addition, it is recommended to align contractual terms and planning processes with emission reduction goals to empower crews to choose more sustainable operating modes. By linking day-to-day operational choices with their emission outcomes, this research provides practical guidelines for offshore vessel operators to reduce their carbon footprint while maintaining efficiency and safety.

This thesis explores the persistent misalignment between formal managerial processes and actual operational practices within shipyard production environments. The central aim is to investigate how a socio-technical approach can enhance the alignment of work systems in shipbuilding, ultimately improving operational effectiveness and productivity. To achieve this, the study applies the functional resonance analysis method (FRAM), enriched with an abstraction hierarchy, to systematically compare work as imagined (WAI) with work as done (WAD) in a case study for an abstracted major European shipyard.
The research is grounded in the observation that the shipbuilding industry is facing significant challenges due to market volatility, technological complexity, labor shortages, and an increasing dependence on subcontractors. Shipyards operate under engineering-to-order (ETO) conditions, characterized by concurrent engineering (CE), bespoke vessels, and high variability. These factors result in a dynamic environment in which formalized processes frequently fall short of capturing the real work performed on the production floor.
A core finding of this study is the clash between top-down control mechanisms and bottom-up operational flexibility. While managerial systems aim for standardization, traceability, and efficiency through techno-centric tools like enterprise resource planning systems (ERP) and manufacturing execution systems (MES), the reality is that production relies heavily on tacit knowledge, informal coordination, and ad hoc decision-making. This misalignment contributes to inefficiencies such as rework, delayed feedback, and ineffective implementation of innovations.
The methodological contribution of the thesis is the development of a novel framework that uses FRAM in combination with an abstraction hierarchy to model and analyze WAI and WAD. Through detailed data collection, formal process documents for WAI and field observations combined with informal interviews for WAD, the method enables multi-level analysis of work functions, their interdependencies, and emergent variability. The comparative analysis reveals that WAD involves more functions and connections, including multiple feedback loops, absent in the WAI, indicating a richer and more adaptive operational reality.
Two specific discrepancies exemplify the misalignment: the absence of explicit operational management functions and proactive material expediting from WAI. Their omission implies that critical functions are informally performed yet formally unrecognized, leading to a lack of support in digital systems and inadequate performance monitoring.
This thesis offers actionable recommendations for both shipyards and software providers like Floorganise. For shipyards, these include formalizing operational management roles, adopting socio-technical frameworks such as the plan-do-check-act (PDCA) cycle and Hale’s rule management model, and improving knowledge transfer through the socialization, externalization, combination, internalization (SECI) model. For Floorganise, the research recommends tailoring tooling to reflect WAD, supporting adaptive planning practices, and expanding consultancy services to help clients integrate socio-technical considerations.
In conclusion, the study demonstrates that sustainable productivity improvements in shipbuilding require bridging the gap between WAI and WAD. By adopting a socio-technical lens and systematically modeling operational realities, shipyards can better align managerial intentions with shop floor execution. The proposed method and findings extend the application of FRAM beyond safety domains into general industrial operations, offering a replicable approach for tackling similar challenges in other complex production settings.

The increasing number of international maritime regulations has significantly impacted the workload of ship surveyors. As compliance requirements grow, surveyors face higher levels of stress, which can lead to human errors and missed deficiencies during inspections. This study explores the potential quality improvement in the survey process by evaluating alternatives for the survey checklist. Using he CREAM (HRA) method, human error classifications and influencing factors were analyzed to identify critical points in the inspection process. Quantifying the human errors in the survey process is done by the use of a python simulation. Besides, four error reduction techniques are implemented to find the potential quality improvement in ship surveys.

The consequences of climate change are becoming more and more visible. A significant cause of this is CO2 emissions; the shipping sector is responsible for 3% of global CO2 emissions. As a result, the Fourth IMO GHG Study 2020 presents pathways to reduce the GHG emission of the shipping industry by 50% by 2050. Recent IMO goals have overtaken this to reduce net emissions to zero by that year.

As a result, research in renewable energy sources has grown in significant interest, offering a wide range of potential solutions. Recently, (green) ammonia (NH3) has been added to these pools, as it is carbon-free and has a higher storage density than liquid or pressurized hydrogen. However, when comparing ammonia to the current conservative fuels, its energy density is still not at the same level, and more fuel volume would be required to deliver the same amount of energy. There are two ways to address this challenge. More frequent bunkering or larger volumes for the fuel tanks on board at the cost of cargo space and thus income. This is a difficult choice to make in the pre-design as it depends on the choices of other owners as well.

This report investigates the impact of a fuel switch to ammonia on the ship design and bunkering pattern based on the current operational profile of 1025 seagoing ships. A mixed integer linear programming model will establish the optimal fuel tank volume and bunkering strategy for each vessel. This model considers rerouting for trips that are not feasible and two approaches for the bunker strategy. Besides, a port model will establish the ammonia bunker pricing based on the resulting demand in each port. The estimated ammonia bunker prices are implemented in the bunker strategy model. This is repeated till a balance is found. The two models represent an Ammonia Powered Shipping Network considering a homogeneous shipping market. The report presents the results and key factors influencing the balance between the fuel tank volume and the sailing range. The simulated bunker strategies show different possibilities for finding this balance and reducing the operational impact caused by the transition to ammonia.

One of the greatest challenges of the 21st century is the reduction of greenhouse gas (GHG) emissions. The shipping industry accounts for 2.9% of global GHG emissions and faces increasing pressure to meet the climate goals set by the International Maritime Organization (IMO) and the European Union, as part of the broader global effort to limit temperature rise to 1.5°C under the Paris Agreement. Al- though the shift towards various forms of alternative fuels in the new-build market is clearly evident, 30% of the global fleet is expected to be non-compliant with the prevailing regulations within the next three years (2023-2026). Replacing all non-compliant vessels with new-builds within this timeframe is not feasible due to the limited capacity of the shipbuilding industry. This presents a critical challenge for the maritime sector, making retrofitting existing vessels a potential, and perhaps even necessary, solution.

Methanol, a cleaner alternative fuel, shows significant promise in reducing GHG emissions, especially when produced from renewable sources, such as Green-methanol or E-methanol. The initial signs of methanol adoption in new-building market appear to be successful, and the retrofitting of existing ships is seems to be feasible both in theory and practice. However, the conversion of an existing ship to methanol propulsion presents challenges, primarily due to the fuel’s lower energy density and its toxic- ity. These factors make the costs for methanol storage in the vessel and operational fuel consumption notably more dominant. Consequently, the potential cost savings from Energy-Saving Devices (ESDs), which can be installed during a vessel conversion, become more relevant.

The main objective of this thesis is to gain deeper insight into which retrofit strategies, in terms of methanol tank volume and the inclusion of ESDs, can provide a feasible option for retrofitting existing vessels to methanol, achieving the intermediate GHG reduction goals. A refit indicator model is devel- oped to evaluate various retrofit strategies, focusing on financial and regulatory performance, given a scenario of price trends and regulatory developments. The model incorporates key operational factors such as trip distance, sailing speed, and bunkering intervals. In a case study, a single base-case vessel was converted into several conversion cases, differing in methanol storage capacity and the inclusion of ESDs, and their performance was assessed under various potential future scenarios.

The results of this study suggest that significant reductions in GHG emissions can be achieved. Pro- vided that renewable methanol is used, it is possible for a methanol-converted vessel to meet the intermediate GHG reduction goals. The regulatory performance of many methanol vessel conversion strategies is also favorable, particularly when a methanol conversion is combined with one or more ESDs. The results showed that, in such cases, vessels can remain compliant for 15 to 20 years longer compared to their non-converted base-case. An important finding is that the shift from a tank-to-wake to a well-to-wake regulatory perspective is a key factor in the success of methanol retrofits. From a financial view, it can be concluded that the strategy of converting to a limited methanol tank volume, combined with a number of highly fuel-efficient ESDs, appears to be the most effective solution for the medium to long term.

With space constraints onshore, strong renewable resources available far offshore
and growing green hydrogen demand, far offshore green hydrogen production
may be an attractive option. To assess this potential, a literature review was
conducted to identify the relevant technologies to be considered and suitable
modelling methods. Next, a mixed integer quadratically constraint programming
(MIQCP) optimization model was set up. The far offshore green hydrogen
supply chain was optimized for various scenarios with this model and the
results were analyzed. It was found that far offshore green hydrogen costs are
in the same order of magnitude as the costs of its alternatives. Far offshore
green hydrogen may be considered marginally competitive with these alternatives
from 2035 onwards in the analyzed scenarios when taking into account the
considerable advantages of far offshore production, such as avoidance of scarce
land usage in crowded areas and certain geopolitical considerations.

The global awareness of the environmental and economic advantages of the circular economy (CE) concept has grown significantly. In order to implement this concept into company practices, a vital starting point is the adoption of a measurement framework. In the past years, the evolution of CE metrics resulted in maturity and practical applicability. However, no method exists able to quantify CE performance specific to a project-based organization. The Material Circularity Indicator (MCI) is one of the most ambiguous methods, which captures circularity with mass as the measurement unit. Alternatively, the Material Circularity Indicator based on economic value (MCI’) is developed as a solution for the reliance of the MCI on mass flow, by using cost-based economic value as the measurement unit. However, existing economic value indicators — as accounts for the MCI’ — are criticized for not including all significant and relevant life cycle cost factors. To solve these implications, both methods are adapted to indicate the CE performance on the levels of interest for a project-based organization: the project, product, and company level. To work from level to level, a bottom-up approach is taken, aggregating using a weighted sum. Additionally, the MCI’ is enhanced by including more life cycle cost factors. The results show that the enhanced MCI’ gives a more accurate estimate of cost-based economic value. Furthermore, the aggregation from the project level to the product and company level, gives valuable insights into the CE performance of project-based organizations.

Strict regulations for carbon emissions from ships are introduced by the IMO and the EU. Various emission mitigation measures and low-emission fuel strategies provide solutions to reduce carbon emissions. This paper compares emission mitigation measures and low-emission fuel strategies for short-sea ships, within the constraints of regulatory compliance. Furthermore, cost sensitivity of measures to fuel, EU ETS and TCE price are compared. The results support shipowners and financiers in making robust investment decisions, and provide insight into the effects of regulatory incentives to regulators.

The maritime industry faces a lot of uncertainty, and the energy transition has only increased this uncertainty. Ships will probably have to be converted to an alternative fuel during their lifetime and methanol seems to be the fuel with the most potential for offshore ships. By preparing for this, Design-for-Conversion to methanol, the costs of changes can be significantly reduced with only minor investments during the new building phase. The added design preparations pay for themselves only if they are being used in the future. However, due to large uncertainties, it is unclear whether a ship is actually converted to methanol in the future. Therefore, an answer had to be found to the main research question: How to determine the value of Design-for-Changeability under uncertainty to find the optimal DFC level when preparing for conversion to methanol?

From the literature is concluded that Design-for-Changeability principles can help to deal with uncertainty during a ship's lifetime. Moreover, Real Options Analysis is selected from the literature, as a method to deal with decisions and uncertainty when designing for conversion to methanol. By means of a combination of these methods, a methodology is established which is used in a case study.

In the case study, it was found that waiting with the execution of conversion to methanol results in decreasing added value of Design-for-Conversion. Moreover, it was found that the Discount Rate used for Net Present Value calculation significantly impacts the choice of whether to prepare a ship for methanol. It can be concluded that an instigator is needed so that ships are converted to methanol. Two instigators have been researched, a carbon pricing measure and a ban on harmful emissions. It can be concluded that a carbon pricing measure is only effective if the right price is established, while a carbon ban is highly effective as ships are converted instantly.

The combination of methods, the Design-for-Changeability principles together with a Real Options Decision Tree, provides a suitable framework to quantify the impact of Design-for-Conversion to methanol under uncertainty.

Ensuring sustainability in shipping extends beyond fuel choices to encompass the responsible use of materials in vessel construction and maintenance. Shifting from the prevailing 'take-make-dispose' model to a circular economy is crucial for enhancing sustainable waste reduction in the industry. Unlike consumer goods, current ship design primarily prioritizes functionality, cost, and operability, neglecting circularity considerations.
To integrate circularity into ship design, this project evaluates and compares frameworks like the butterfly diagram, Cradle-to-Cradle, 10R, and ReSOLVE. The chosen approach combines the 10R framework with the Material Circularity Indicator method, offering practical insights and manageable efforts for addressing circularity in ship design. The 10R framework includes strategies like Refuse, Reduce, Redesign, Reuse, Repair, Refurbish, Remanufacture, Repurpose, Recycle, and Recover, each providing a design strategy for circularity in consumer goods.
However, integrating these methods into standard design processes proves challenging due to the lack of structure. To overcome this, the 10R design strategies are fused with systems engineering, allowing for the assessment of circularity and identification of key areas for improvement in ship designs. This approach emphasises the need for a renewed system, enabling the redesign of systems with a dual focus on functionality and circularity.
Demonstrated through a case study on the wheelhouse, the framework assesses various sub-systems for their circularity levels and redesigns one sub-system, showcasing the potential for a systems engineering approach to enhance circularity. Supplier collaboration is pivotal for the framework's success, facilitating information exchange and elevating the circularity of products offered.

Shipping companies aim to reach the climate goals by following the rules from the International Maritime Oranization (IMO), which includes reducing Scope 3 emissions. Maintenance is a great contributor to the Scope 3 emissions of a shipping company, especially the transportation of spare parts. The current state-of-the-art supply chain optimisation for spare parts is based on cost and risks. This study aims to find the potential influence of including Greenhouse Gas (GHG) emissions into the decision-making process for the logistics of spare parts. The element of the supply chain that makes it possible to plan when a spare part is needed is the maintenance policy. Planning in advance when a part is needed is possible for Preventive Maintenance (PM), which is therefore used in this research. A model can be created by limiting the amount of risk, optimising between the freight cost, the cost of GHG emissions and the cost of capital for alternative delivery locations, using brute force calculations. This model is applied to a case study of a chemical tanker from Stolt Tankers B.V., using available data on its job history and historical location data. From the case study follows that including the GHG emissions in the decision-making process adds an additional saving in emissions and cost with respect to the original situation. It can be concluded that the amount that is saved depends on the choices of the decision-maker. The model presented in this paper is a valuable tool for providing insights into the decision.

A vessel’s life cycle consists of the design, construction, operation, and scrapping of the vessel. Current scrapping practices often happen in South Asia and Turkey, where adverse impacts on the environment and people’s health and safety manifest itself. These negative impacts fuel the growing global criticism on the vessel dismantling industry. Academic research on this topic has mainly been focused on qualitative research of the extent of the impact, while minimal research is dedicated to the understanding of alternative dismantling processes, which could improve industry standards. Several factors including regulations and a changing market dynamic of the steel industry enabled new parties to potential market entry of the vessel dismantling business. The new parties aim to include high standards of waste management and no social harm in their business, by relying on a technology driven dismantling process. These circumstances and alternative dismantling concepts in developing countries justify an investigation on the level of competitiveness, compared to the conventional labour-based dismantling concepts of South Asia and Turkey. Therefore, the main question of this research is:
What is the level of competitiveness of technology-based, environmentally sound vessel disman-tling located in North Western Europe?
In order to create an understanding of the level of competitiveness of technology-based dismantling, a thorough analysis of the underlying problems causing global criticism had to be performed. Through literary research the historical developments and drivers of the industry have been identified in chapter 2. The adverse impact on coastal ecology and involved occupational hazards and child labour is proven in section 2.2. Following this, regulatory frameworks were drawn up to improve the workings of end of life vessel management. This resulted in more reliance on developing economies adhering to poor enforcing regulation due to non-uniform ratification of the frameworks, as discussed in section 2.2.2. Earlier research on measurement models for sustainability within the dismantling industry was mainly focused on high over managerial and social practices, instead of the dismantling process from an operational-economic perspective.
The identified knowledge gaps required for answering the main question formed the basis of the scope structuring and research methodologies. For the research methodology discussed in section 3, goal oriented identification of the best fitting method is maintained. The first area of interest for answering the main question came down to selecting and valuing the most potent feedstock for the designated area. The commercial segments and sizes are based on data analysis and holistic data set enlargement. Thereafter, selecting an adequate method for quantifying all material streams of vessels is of importance to create an understanding of the material flows and economic return of the dismantling process. Subsequently, technology-based dismantling could be investigated from an operational perspective. From the understanding of the operational requirements, the link could be made to the required investments and operational expenses. The ecological and social impact required a quantification method that would allow for inclusion in the economic performance of technology-based dismantling. By doing this, a single unit parameter can be used for answering the main question. An overview of all relevant added values and costs, impacts and streams is presented in a sustainable value stream map.
Finally, a case study was selected representing technology-based dismantling in the simulation performed. The concept which matched the scope of this research best is Circular Maritime Technology. From the simulation and calculations performed in accordance with the selected methodologies could be concluded that there are both opportunities and challenges for technology-based dismantling concepts in North West Europe. Matching the pricing level of Turkey is found to be economical viable, whilst competing with South Asia requires a level of true pricing allocation in the economic value. For operational viability, minimising the turnaround time of vessels is key for spreading the high investments over enough earnings. Adhering to the right pricing level for vessel acquisition and steel sales is key. Especially in the current phase with the absence of incentives and taxation frameworks promoting sustainable vessel dismantling.

In the global energy transition where the shift from fossil fuels to renewable energy is needed, wind energy is a growing industry. In the offshore wind industry, Service Operation Vessels (SOVs) are needed to operate and maintain wind farms. To reduce the environmental footprint of SOVs at offshore wind farms, the possibility of battery-electric sailing with plug-in charging at offshore wind farms is investigated. Battery-electric sailing has been applied to many vessels, however, it is mostly applied to ferries which operate with a fixed daily schedule. An SOV has a variable operational schedule and therefore the energy use calculation is more complex than for a fixed operational schedule.

At the root of calculating the daily energy use are the daily schedules of the SOV. The daily schedules are determined by the maintenance strategy applied by the contractor, and the optimisation of the vehicle routing problems. However, in the concept design phase, this method is too detailed to get a useful and trustworthy result. A discrete event simulation is suggested to create daily operation schedules of the SOV where the power and duration are still calculated for, but the too-detailed routing information is left behind. The daily schedules are structured as a vehicle routing problem with delivery and pick-up with full-day and half-day tasks. They are influenced by wind farm characteristics, vessel characteristics, and operational characteristics.

With the information that is known about the daily schedules and the input parameters, a Monte Carlo simulation is deemed the most appropriate. This method takes into account the likelihood of input variables, can deal with these uncertainties, and still give a useful, trustworthy, result. The model creates many daily schedules of which the resulting maximum energy use, by the law of large numbers, converges to the expected value. For the idle time, a charging module is implemented to make the choice between standby and charging.

A case study is done to look at the influence on the results of design choices and boundary settings. The inputs that are varied during the case study are: with or without charging, the number of charging points, the layout of the offshore wind farm, the workday length, the task distribution and the charging power. The daily energy use results for a 12-hour workday vary from a bit over 4000 kWh with not that many tasks and six charging points, to over 10000 kWh for many tasks and only one charging point. Individual inputs can make a difference from 500 to 3000 kWh. The case study gives a good insight into how much influence different parameters have on daily energy use and shows that offshore charging during the day can drastically reduce the maximum battery energy needed during the day.

This paper investigates the spatial requirements of alternative marine energy carriers and their impact on ship design and powering for constant operational requirements. A parametric design tool for bulk carriers, tankers, and container ships has been developed for the predicted future marine energy carriers to determine the main engine brake power increase. The results indicate that all ship type and energy carrier combinations require a higher total installed engine power and consequently a higher energy carrier consumption. The results are intended to support the determination on the total environmental impact of marine energy carriers while taking the increased energy consumption into account.

This thesis investigates the total environmental impact of various alternative marine energy carriers while taking the powering increase into account due to their disadvantageous spatial requirements compared to conventional fuel. A parametric design tool for bulk carriers, tankers, container ships, and trailing suction hopper dredgers has been developed for the future marine energy carriers to determine the total installed engine power increase. A more environmentally friendly energy carrier can be overturned because the total installed engine power increase is proportionate to the energy consumption increase. A comparative life cycle assessment (LCA) has been performed on fuel oil, methanol, LNG, liquid hydrogen, ammonia, and batteries for the conventional and a bio/renewable version of their well-to-wake pathway. The powering impact results indicate that all ship type and energy carrier combinations require a higher total installed main engine power and consequently a higher energy carrier consumption. The total environmental impact results indicate that only renewable liquid hydrogen and renewable ammonia have less adverse effects on global warming, and cause less damage to human health, ecosystems, and natural resource availability.

Many recycled materials in different industries are traceable. The recycled content is often known in percentages. Steel is a material which gets recycled almost 100%. However it is not common practice to specify the recycled content for steel products. From a sustainability point of view this information can be very valuable. This thesis identifies the barriers and opportunities for a class notation that specifies the recycled content of a vessel or marine structure. Furthermore, the way certification of steel would influence trust, traceability and transparency of a circular economy in the shipbuilding industry has been investigated. This was done from the point of view of a classification society but to reach the conclusion, the entire shipbuilding value chain has been investigated. Semi structured interviews were held with different stakeholders from the ship building value chain. These interviewees were steel manufacturers, original equipment manufacturers, ship yards, recycling yards, classification societies, financial institutions, ship repair yards and shipping companies. Barriers that were found are, amongst others, technical feasibility, steel market, yard logistics, customer willingness to pay, green washing, ship recycling standards, demographic differences, etc. The first conclusion is that, although sustainability is high on the agenda for most companies, the efforts and goals on this matter are scattered and uncoordinated. All stakeholders, except for the steelmakers, see the benefit for certification of recycled steel in terms of increased sustainability. The steelmakers possess the ability to provide all necessary information and there are no technical barriers. This means that they are able to provide steel products with a specified percentage of recycled content. The main barrier for different stakeholders are the extra resources they need to spent to incorporate a new type of certification into their business processes. None of these stakeholders want to take the risk as a single player, but are willing to take part once collaboration amongst all stakeholders are guaranteed. This creates the business opportunity for classification societies to provide this opportunity and take the lead for this innovation. A review of current certification steps for steel products has been made and adapted to include extra steps to certify the recycled contents. The effect of this extra steps with regard to stakeholders downstream has been investigated and validated by means of the interviews. Another topic is the digitalisation. Because of the increased ability to process big data, there are opportunities to tackle certification of recycled products and the subsequent traceability by means of blockchain technology. These opportunities are identified and are proposed as optional further research topics.