To reduce the greenhouse gas emissions of ships, hybrid power systems are becoming more common. Hybrid systems combine power generation with energy storage. The energy storage enables the power generating components to run at more efficient operating points. A well known combination is that of a diesel genset and a battery. The ideal combination of the type, size, and amount of power system components depends highly on the operating profile of the vessel. However, this operating profile can vary greatly between voyages, or during the lifetime of a vessel, thus changing the ‘ideal’ power plant. A modular power system (MPS) can provide the solution: a reconfigurable power plant, where components can be added, removed, or replaced.
To control the power-split between the different components an energy management system (EMS) is required. Most EMSs are designed and optimized for a single power plant configuration. This means they are not capable of dealing with an MPS. For this thesis an EMS was developed which is capable of dealing with an MPS: an MPS EMS. The developed EMS was made for ships with electric propulsion. An additional requirement was for the EMS to be real-time capable, so it can be used outside of a simulated environment, i.e. in a real ship. The objective of the EMS would be to minimize fuel consumption.
It was investigated which EMS control strategy would be suited for an MPS EMS. The equivalent consumption minimization strategy (ECMS) combined with the dual decomposition method was found to be suited for this purpose.
The developed EMS can automatically adapt all parameters responsible for stable control of the system. It does this based on the properties of the installed components. Most important of these properties are: minimum and maximum power output, maximum ramp-rate, and the efficiency curve.
The EMS was tested with four different combinations of installed components, and two different operating profiles. Additionally, the effect of a component failure during a voyage was tested. A rule based (RB) EMS and a mixed integer linear programming (MILP) global optimization were used as benchmarks for the fuel consumption. The results show that the developed EMS is capable of controlling various power plant configurations in different conditions, while keeping all components within their allowed operating ranges. For one of the tested operating profiles the fuel consumption using ECMS was 1.9-4.0% higher than when using the global optimization, which is comparable to the results found in literature. However, for the other tested operating profile the developed EMS was outperformed by even the RB EMS, by 1.1-2.1%. This was caused by inaccuracies of the approximation used for the efficiency curve of the gensets. In the simulations where one of the gensets fails during the voyage the EMS was able to automatically adapt to optimize fuel consumption using only the remaining components. Fuel consumption did increase slightly compared to no failures, as expected.

Today’s necessity- and goal to reduce carbon emissions in tandem with finite fossil resources and rising oil prices, demand for an alternative and cleaner energy source to power the world dredging fleet. In parallel, recent research in naval architecture iterates the potential role for nuclear-based propulsion on board of ’energy-intense’ merchant vessels (approx. 20 MWe+ installed power) [16][20][23]. Powering a (large) trailing suction hopper dredger (30.000m3+) by an on-board small modular nuclear reactor would cut direct greenhouse gas emissions by 100%.

The power demand on board of trailing suction hopper dredger is fluctuating continuously. A reactor is typically applied for supplying constant power. The objective of this thesis was to research the transient load capabilities of a nuclear-powered trailing suction hopper dredger.
First, for the on-board nuclear installation, a graphite-moderated high temperature gas reactor was opted for which is cooled by helium gas. This reactor type has a technology readiness level of 9 and small-modular-reactor concepts of this type are being developed. Both the open- and closed helium Brayton cycle concepts show greatest potential for power conversion. It was shown that the reactor, the heat exchangers and the turbomachinery play an important role in both the overall efficiency of operation and the transient load limits of the system as a whole.

Second, a thermodynamic model was built to be able to simulate the effects of different control mechanisms in realising load-following. Bypass- and compressor throttling control performed best and allowed the reactor to ramp down at lower rate, which is a favourable feature. For a 100% reduction in power output, the reactor would have to ramp down to 47% and 34% of nominal power respectively.

Third, it was investigated how the limitations in load-following would effect the operational profile of a HTGR-powered TSHD. The suggested closed helium Brayton cycle cannot perform adequate load following to the fluctuating demand of a conventional TSHD today without an auxiliary source of energy. When keeping reactor ramping rates below 10%/minute, a 25MWe HTGR-powered TSHD would see peaks in power imbalance up to 10 MW. However, a 3MWh ESS was considered to perform power take-in and power take-off. In presence of such auxiliary power source, the operational profile of a TSHD would not have to be changed.

Looking ahead, it is crucial to investigate the impact of repetitive power transients on the controllability and lifespan of both the reactor and other components within the power cycle. Additionally, a more in-depth study of the aerodynamic characteristics of the helium turbomachinery is necessary. Lastly, incorporating supplementary nuclear kinetics analysis could help validate the findings presented in this report.

The Dutch Ministry of Defence (NLMoD) has stated the goal of reducing dependency on fossil fuels by at least 20% by the year 2030 and at least 70% by the year 2050 compared to the year 2010. Research in the NLMoD explores the possibility of changing diesel-fuelled vehicles and weapon platforms to alternative forms of energy such as electric or sustainable fuels. In these projects, the focus is on (part of) the vehicle or energy source itself, but the impact on the Military Supply Chain (MSC) is missing.

This research has developed a Mixed Integer Linear Programming model that can be used to gain insight into the impact of the energy type of tactical vehicles and weapon platforms on the MSC and therefore is able to see what energy type has the lowest impact on that MSC. The impact on the MSC is measured by minimizing the refuel time, number of supply trips, and CO2 equivalent emissions. The model can provide insight into what the minimal requirements of potential energy carriers and conversion devices should be in order to have a similar or better impact on the current diesel MSC. The model is based on the current supply chain of the NLMoD and is expanded with the use of APUs for vehicles, energy generation at Nodes, the use of small supply trucks as energy buffers, compatible supply material, and longer self-sufficient times. Combinations of these are looked at in different policies.

Results show the trend that energy types with lower CO2 equivalent emissions have higher refuel time and number of supply trips. An exception to this is HVO and HVO-electric series hybrid, which also have the least impact on the MSC. Energy types such as hydrogen and electric require huge improvements in energy density, fill speed, and FTW efficiency to come close to the results of current diesel.

Electrification of numerous end-users is a worldwide trend to address climate change, according to the International Energy Agency. This trend has also reached container terminal operators. Currently most of the ship-to-shore cranes employed are electrified, leading to an increase in the required electrical power demand and to an increase in the volatility of the electrical power demand of container terminals. As a result, the contractual power demand charged by the grid operator, based on the maximum required power demand (peak power) at any moment in time, is upscaled, leading to additional costs for the container terminal operator. However, the highest required power demand values occur infrequently, leading to significant expenses for a resource that is rarely utilised. By implementing a peak shaving strategy, the peak power can be reduced, leading to a decrease in the contractual power demand related costs. Nevertheless, it is crucial to minimise the impact of the specific peak shaving strategy on the productivity of a container terminal to actually derive economic benefits from its implementation.

The aim of this study is to develop operational policies that effectively maintain productivity for a cluster of six ship-to-shore cranes under increasingly restrictive peak power limitations. A discrete event simulation approach was employed for evaluating the operational and economic impact. In total four policies were developed, two according to the `who fits is served' approach (policy 0 and policy 1) and two according to the `priority based' approach (policy 2 and policy 3). In the first approach the initiation of a movement only depends on the power availability, while for the second approach the initiation of a movement depends on the power availability and the urgency of the movement in terms of productivity. Moreover, for both approaches one policy allows only one kinematic profile (policy 0 and policy 2) and one policy allows varying kinematic profiles (policy 1 and policy 3). A metaheuristic was employed to find near-optimal adapted kinematic profiles.

The findings of this study suggest that the established `priority based' approach is more effective than the `who fits is served' approach in maintaining productivity under increasingly restrictive peak power limitations. When combined with the allowance of adapted kinematic profiles (policy 3), this strategy achieves the most cost savings. Policy 3, has been shown to reduce the contractual power demand related costs by 53\% compared to the baseline scenario, which is the greatest recorded reduction of all created policies without adversely affecting the ship-to-shore cranes' productivity.

Green hydrogen plays an important role in the energy transition. It can function as a storage medium, as well as a replacement for fossil fuels in transport or high-temperature heat processes. However, the economic feasibility of electrolysers has proved to be a problem. Even though a lot of research has been done to the electrolysis technology, very few research has been done to the implementation of an electrolyser.

For this research, a physical model of an electrolyser has been developed, as well as an Energy Management System (EMS). For this system, trading strategies for electricity markets have been developed. By trading on the imbalance and day ahead market, the contribution margin (hydrogen revenue minus electricity costs) has been significantly increased by over 27%. Seasonal hydrogen storage in salt caverns has proven to be a promising solution for producing more hydrogen and increasing revenue, depending on the storage costs that are applied. A Battery Energy Storage System (BESS) has been added to the system for its competence in dynamic behaviour on the electricity markets. For the addition of a BESS to an electrolyser, no conclusive proof of the benefits for the economic viability of green hydrogen has been found.

Due to the growing demand for offshore wind energy and the increasing wind turbine sizes, a shortage of capable installation vessels is anticipated by 2024. Consequently, the utilisation of heavy-lift vessels, previously not employed for bottom-founded or floating offshore wind turbine installations, may become imperative to realise the offshore wind project pipeline. Therefore, this study analyses the technical and economic feasibility of installing floating wind turbines with the largest construction vessel in the world named the Pioneering Spirit. For this, the concept development stage of the systems engineering method was applied, consisting of three successive phases. Firstly, in the Needs Analysis phase, valuable insights regarding the operational environment were obtained, resulting in operational requirements for the concept design. Secondly, in the Concept Exploration phase, these requirements were used for generating multiple alternative concept options after which the most promising concepts were selected for further analysis through a trade-off analysis. Lastly, in the Concept Definition phase, the technical feasibility, workability and economic feasibility were evaluated for the selected concepts. The technical feasibility was assessed by creating storyboards for the different installation procedures, determining the stability of the barge named the Iron Lady for different load cases and providing technical descriptions of performed operations and required equipment. Furthermore, the workability was estimated by comparing statistical wave and wind data with the environmental limits for various operations obtained through literature, previous projects and a motion analysis model. Subsequently, with the storyboards and workability results, the economic feasibility was determined with a model that included estimations of the vessel and fuel costs for constructing a reference wind farm located at a variable distance to shore. Ultimately, it was found that Spar- and TLP-type floating wind turbines are of most interest for the concept design and that the Pioneering Spirit is in principle capable of installing the corresponding pre-assembled foundations and wind turbines relating to a capacity of 15 megawatt with a single-lift operation. Furthermore, this research gives valuable insights that extend beyond the initial scope of this paper. Since the performance implications of the selected concepts related to the workability assessment and economic feasibility study can directly be linked to specific design choices and limitations. This, in combination with the exploration of floating wind turbine installation with alternative lifting equipment, can be used to provide recommendations for future designs of purpose-built vessels in this sector. Finally, the methodology used in this study could be applied to evaluate the feasibility of other potential concepts for deployment in this area.

Chain belt conveyors have become a popular choice for transporting materials in diverse industries. The primary driving force behind these conveyors is the gearmotor, which is composed of an electric motor and a gear unit. The industrial electric motor market is estimated to be 21 billion USD and consumes up to 70\% of the electricity by the industry. However, research on chain belt conveyors systems remains limited, leading to poor maintenance strategies and inadequate understanding of their efficiency. The aim of this paper is to develop a digital twin for condition monitoring, applicable to industrial gearmotor-driven chain belt conveyor systems. To achieve this, the current state-of-the-art and industry practices were analysed, focusing on SEW Eurodrive as a representative for industrial industry. A literature review was conducted to explore predictive maintenance, digital twins and condition monitoring in the context of chain belt conveyors. Consequently, this has culminated in the development of a novel chain belt conveyor model, based on fundamental mechanical analysis of the chain belt conveyor, while also acknowledging the limitations associated with industrial settings. In order to accomplish this objective, parameter estimation was performed for system identification using data collected from physical chain belt conveyor systems. Additionally, various methods have been proposed for anomaly detection, which include the utilization of estimated parameter thresholds, frequency domain analysis, statistical residual analysis and the assessment of the transport loss factor. Verification and validation have been performed using data from a chain belt conveyor system. Eventually, a case study was conducted with promising results in terms of robustness and accuracy. In the industrial setting, dynamic weighing attained a benchmark accuracy of 95\%. Further research, with data over longer periods of time, is required to establish degradation patterns and optimize the model for broader applications.

This research analyses the potential of Electrical Signature Analysis (ESA) as a means for condition monitoring of mechanical defects of induction motor driven thruster assemblies in the maritime industry. This is done by measuring the three phase current and voltage of three thrusters, with different health conditions, of a marine vessel sailing at different speeds. In this data, the mechanical behaviour of the machines is detected by plotting the frequency spectra of various electrical parameters, such as complex current and torque. After successfully identifying mechanical behaviour and defects, a suggested approach for the implementation of ESA as a means for condition monitoring is presented.

The process of salvaging wrecks can be costly and time-consuming, making it crucial for salvagers to select the appropriate technique(s) and accurately estimate the total costs to minimize expenses and optimize efficiency. Salvagers typically use their expertise, experience, and data from previous projects to make these estimates. Diamond wire cutting is a material-cutting technique with much potential for use in wreck salvaging. However, a previously conducted literature review revealed a lack of sufficient information in the existing literature to determine the cutting rates of diamond wire used in wreck removal, indicating a gap in current knowledge. A deeper understanding of the technique is needed to evaluate salvagers' capability of cutting diamond wire in wreck removal. Therefore, the primary focus of this paper is to provide a method to estimate the cutting rate of diamond wire when used in wreck removal. The effect of wire speed, normal load on the workpiece, various materials encountered in wreck cutting, different geometries, and environments on cutting rate have been investigated. Filling this knowledge gap is of particular interest to Boskalis, as they currently have limited knowledge and experience with diamond wire cutting, making it challenging to estimate costs. Additionally, research into wreck removal techniques is socially significant, as the ability to remove wrecks efficiently and with minimal environmental impact is crucial. Therefore, this thesis aims to provide a deeper understanding of diamond wire cutting in its application in wreck removal.


Main factors determining the potential of a technique for removal include the total duration of removal, the required assets, and the associated risks. The primary focus of this thesis is to develop a method to estimate the cutting rate of diamond wire when used in wreck removal. The cutting rate will be predicted using the Archard wear equation, which requires an unknown coefficient ($K$) that can be determined through experiments. A real-world set-up with diamond wire was used to obtain data.

The results show that for the steels and cast iron in this survey, Archard's assumption that the wear volume is inversely proportional to hardness is not supported. Consistent with Archard’s equations, the wear volume has been found to be proportional to normal load, sliding distance but independent of speed within the range of tested conditions. As such, the Archard wear equation can be applied to the materials tested, but its applicability to materials that differ significantly from those tested is uncertain. Furthermore, results show that cooling significantly impacts both wire life and cutting rate. Specifically, fully submerging the workpiece resulted in a
XX\% improvement in the cutting rate as compared to spraying with coolant. It should be noted that these results were obtained under controlled conditions where normal load, wire speed, and cutting angle were kept constant, and proper cooling was possible. These operational parameters may vary in real-world scenarios, such as cutting through a shipwreck, leading to deviation from the predicted cutting rates.

Climate change due to greenhouse gas emissions is prompting the IMO to reduce emissions by 80% by 2050. This thesis focuses on designing modular propulsion systems for mid-speed sailing vessels to meet these regulations. It designs a framework to generate and swiftly evaluate propulsion system designs on the basis of five performance indicators: Weight, Volume, Life Cycle Costing, Modularity and Emissions. Additionally, the framework is proven on the basis of a case study, which results in a modular concept.

The company H2 Marine Solutions has designed a zero-emission hydrogen powered boat. This boat is compared to its fossil fuel counterpart more than twice as heavy. The reason for this is that the system components that are used in the hybrid powertrain of the hydrogen powered boat are heavier. The main question of this research is: How can we establish the optimal energy and power of the system components of a hybrid power system with optimal energy management for a zero-emission hydrogen powered boat for different operational profiles? This results in a sizing and control optimization problem. Because these two problems are coupled this is a multi-objective double-layer optimization problem. The most popular strategy to solve this problem is with the control problem nested in the sizing problem \cite{Hybrid-ship}. The most popular algorithms to solve these problems are evolutionary algorithms.

Unfortunately due to the complexity of these algorithms and due to lack of time the sizing and control problems are solved separately in this research. First, the system components of the plant are described and modeled. The components that are modeled are the battery, the fuel cells, and the DC/DC converter. To find the optimal energy management strategy an online optimization strategy is used. This is done because the problem is solved in real-time than and could be used in a real application. The strategy that is chosen to solve the control problem is the Equivalent Consumption Minimization Strategy (ECMS). This strategy translates the electrical energy from the battery into equivalent hydrogen consumption. For every timestep, the equivalent consumption is minimized by the ECMS. Because there are different variants of ECMS three of these variants are discussed and compared in the research. Also, two rule-based energy management strategies are compared. The sizing problem is described by linear equality and inequality constraints. The problem is solved by the Linprog function in Matlab. The objective of the sizing problem is to minimize the weight of the system components. The input in the sizing problem is the energy and power demand of the most energy intensive operational profile. After solving the sizing and control problem the results are combined and the different operational profiles are used as input to show the robustness of the optimization.

The three different energy management strategies all minimize the instantaneous equivalent consumption but show different behaviors when controlling the system components. The optimal energy management strategy is the Smooth Adaptive Penalty (SAP)-ECMS. With this controller, the fuel cells work on a steady operating point and ramp up and down the output power smoothly when necessary. Due to this behavior, the average efficiency of the fuel cell is the highest, and the hydrogen consumption is the lowest compared to the other controllers. The results of the sizing problem show that the weight will decrease when a bigger fuel cell is used in combination with a smaller battery. The consideration between a bigger fuel cell and a smaller battery is a consideration between lower weight and more hydrogen consumption. When a bigger fuel cell is used it is recommended to implement an optimal energy management strategy such as the SAP-ECMS to control the output power of the system components. This is preferable above a rule-based controller which can not find the optimal operating point at all timesteps. Even better energy management strategies may exist or could be made by combining different ECMS's. When the sizing and control problem are solved in a nested strategy more accurate results could be achieved.

With the rapid advancement of technology, we are moving towards a society that is increasingly driven by computer intelligence. At the same time, we are facing pressing environmental issues that are pushing us towards cleaner solutions. One industry that is heavily influenced by these two factors is the automotive industry, where autonomous electric vehicles are gaining more popularity. Audi AG, one of the biggest car manufacturer companies, is now trying to take a step forward in this market by implementing two low-voltage energy sources into the system to improve automation features. The main obstacle to the introduction of these energy sources is the strong influence that temperature has on them. Both high and low temperatures are detrimental to the battery's lifespan and performance and, in extreme conditions, they may completely impede the energy source from supplying energy or lead to thermal runaway. Therefore, effective thermal regulation of the energy source is fundamental to ensure battery availability and enhance efficiency. The objective of this research is to develop a new thermal regulating system for low-voltage energy sources in autonomous electric vehicles.

A major transition became necessary for the maritime industry to meet the IMO’s targets for mitigating the carbon footprint of the sector by at least 50% by 2050. One of the promising methods to lower the emissions is the ship's hybridization. An enormous increase in pilot and demonstration projects for that purpose is being observed. This research was contacted through the involvement of TU Delft in such a project called the Implementation of Ship Hybridisation.

The design and optimization of hybrid propulsion systems is a complex and challenging task due to the different power sources involved and the dependence on the energy management and control. The physical system and the control algorithm should be designed in an integrated manner to obtain an optimal system design. This study applies a multi-objective double-layer optimization methodology to optimize the sizing and energy management of a hybrid ship propulsion system to be installed on a Crew transfer vessel. A proposed hybrid topology which combines diesel engines, batteries and fuel cells is considered. The proposed approach incorporates the development of fuels and electricity prices as well as the investment costs of the system’s components as an uncertainty element. The introduction of emission reduction measures such as carbon tax was also considered in the study. Future trajectories for the relevant uncertainties were developed and incorporated in the optimization methodology to provide decision-makers with a more realistic picture of the solution space.

The analysis of the optimization results was based on the Total cost of ownership (TCO) and the emission reduction potential of the optimal designs produced by the optimization methodology. The results show that instead of choosing a hybrid propulsion system for the vessel under study, an all-electric propulsion system which is based entirely on batteries and fuel cells is the most economical and environmentally friendly option. Incorporating diesel engines has a negative impact on the operational expenditures of the system in the long term. A fully electric propulsion system would require a larger initial investment from the ship owner, but it would pay off over the course of the ship’s remaining useful life.

This research can be used as a reference to base the decision of the stakeholders on choosing a new propulsive system for their vessel. The parameters of the optimization methodology can be easily changed to explore more options and expand the design solution space if this thesis’ results don’t satisfy the shipowner. In addition, it is suggested that a professional user interface designer be involved in the development of a real life decision support tool, incorporating the multi-objective optimization methodology.

Due to more stringent greenhouse gas (GHG) emission regulations in the maritime industry, solutions are being sought to decrease the GHG emissions of crew transfer vessels used in offshore wind farms. Multiple alternative fuels and power generating systems can be used to decrease these emissions. In this research, a comparative study is performed on six concept solutions. Four fuel types (hydrogen, HVO, methanol, and renewable energy) and three different power generating system components (proton exchange membrane fuel cells, lithiumion batteries, and internal combustion engines) are considered. The option of charging a battery-powered ship offshore is also considered. The goal of this research is to identify the most cost-effective system to reduce GHG emissions. The comparison is based on the total cost of ownership, the GHG emissions of fuel production and utilisation, and the GHG emissions of the production of the power generating system. In order to achieve this, the component sizes and lifetimes are calculated based on the constraints of the ship and the operational profile with different transit distances to the wind farm. The lifetime of the fuel cell is based on a cell voltage degradation model developed in this research. A battery electric ship with a methanol genset is found to be the best method with the largest GHG emissions reductions in relation to cost. Without charging offshore for a transit distance up to 18 km, and with offshore charging beyond 18 km. If charging offshore is not considered viable, a combustion engine with hydrogen is the best option for a transit distance of 18 km up to 68 km, and HVO upwards of 68 km.

Over the coming decades the worldwide fleet of ships will have to change to reduce emissions. Hybridisation of the propulsion system is a stepping stone to full electrification, which is required to reduce emissions of the maritime sector to zero. In hybrid propulsion systems, clutches are used to switch between drive engines when transitioning between operational modes. The operation of clutches is indicated to generate significant disturbances in propulsion systems, however, this impact is overlooked in hybrid propulsion simulation studies in the scientific literature. The identified research gap is addressed in this thesis by simulating propulsion mode transition in a hybrid propulsion system and analysing the impact of clutch operation, using a model developed for this purpose. A hybrid propulsion system is defined by introducing multi disk wet friction clutches in a reference propulsion system consisting of a 9.1 MW diesel engine in parallel with a 3 MW electric motor. A broad scope of impact measures, that includes the electric load on the power system and the temperature development of the clutch, is defined and the system is thoroughly modelled to enable evaluation of these measures. The transmission system is modelled with a higher fidelity than typically applied in propulsion system simulation studies to enable assessment of the basic vibratory behaviour of the transmission system. The considered propulsion modes transitions are between diesel and electric propulsion. To enable these transitions, three transition control approaches with an increasing degree of sophistication are implemented. The developed model is used to perform simulations, from which it is concluded that torsional vibrations, gear hammer and a drop in propeller speed characterise the significant impact of clutch operation on hybrid propulsion systems in propulsion mode transitions. It is also concluded that the impact of clutch operation can be limited by implementing an appropriate propulsion control approach for the transition. A torque controlled handover of drive torque between engines is identified as a suitable approach. However, the induction machine switching from torque to speed control introduces power peaks in the load profile that have the potential to severely disrupt the stability of the ships power system. It is finally concluded that the temperature development of the clutch during the propulsion mode transitions is not significant. It is shown in this thesis that there can be a significant impact on the propulsion system as a result of the operation of clutches in propulsion mode transitions. Therefore, this impact has to be taken into consideration when designing hybrid propulsion systems. The model described in this thesis can be used to predict the impact of clutch operation in the early stages of the design process. Furthermore, the model can be used to develop and evaluate propulsion mode transition control approaches.

New trends in the offshore wind industry show that wind farms are being built further onto sea. This also means that turbines have to be installed in deeper waters resulting in new challenges for the offshore wind industry. The commonly used jack-up vessels have a limited operating depth and therefore floating installation vessels become an interesting alternative. The downside of using floating installation vessels is that they encounter more unwanted motions. A motion compensating tool can help to decrease the negative effects of the unwanted motions. The designing steps for a motion compensating tool are presented resulting in a final concept design. The concept is eventually worked out in a mathematical model to evaluate the dynamic behaviour.

This paper describes a real-time energy management system developed for a solar park in the Netherlands using an alkaline electrolyser. The optimization problem is split into a two-step optimization, taking into account the specifications of the electrolyser and allowing the electrolyser to respond to changes in the imbalance market. The first optimization step determines the state of the electrolyser one day in advance. The second optimization step determines the electrolyser power, using the state of the electrolyser as an input. Simulations using data from 2020, 2021 and 2022 show that the use of the electrolyser is limited to a number of days in the year with a lot of solar generation, causing the day-ahead prices to be low. Different scenarios have been tested to get insight into how the use of the electrolyser is influenced by these changes. The type of electrolyser, being able to put the electrolyser on standby and allowing the grid to be used for the electrolyser hardly affected the results. At last, different hydrogen prices are compared. The higher hydrogen prices lead to more use of the electrolyser. This real-time EMS contributes to the ability of an alkaline electrolyser to respond to the sudden changes in the grid and by doing this making it possible to use alkaline electrolysers for balancing the grid and contributes to the use of green hydrogen in the industry for a competitive price.

Increasing emissions have led to the search for alternate power systems to provide energy for maritime applications. The recent drop in battery prices (over 200 % in the last ten years) has made battery energy storage one of the practical alternatives for fossil fuels to curb emissions and reduce the carbon footprint of the maritime sector. The main criterion for choosing a ship’s battery system is its operational profile. Therefore, this study estimated and studied the operational profiles of three use cases - Superyacht, Bulk Carrier and Ferry. The information about the power requirements for ship activities was obtained from the operational profile. Based on that information, different strategies were presented to implement battery energy storage for each use case. A rule-based controller was developed to simulate the power split between the IC engines and battery packs for hybrid systems. Battery packs were sized according to the batteries’ energy consumption, which was found using the design criteria for each use case. A State of Charge (SOC) estimation model based on Coulomb Counting was developed to study the load cycles of the batteries. The SOC profiles were estimated for the proposed battery-powered systems and then characterised for each use case. Finally, a comparison between the conventional power system and the proposed battery power systems was made based on fuel consumption and greenhouse gas (GHG) emissions.

This research examines the possible pathways and available technologies that will help the shipping sector to achieve the climate goals set by the IMO. Reaching these goals will require financial incentives and policies regarding sustainability. These policies need to describe regulations at both international and regional level given the maritime sector’s 3% contribution to GHG emissions (Tatar & ÖZER, 2018).Previous research examines only the performances of the new technologies. This research includes both aspects to assess the different options, from the sustainable point of view as the business point of view.The goal of this researchwas to investigate the possibilities to apply renewable energy sources to a vessel that transports polymetallic nodules from the Clarion-Clipperton Zone to Mexico in order to reduce the carbon footprint. Besides this, also look into which of these possibilities has the lowest costs. For this purpose, multiple propulsion drive train systems were examined which were based on the Panamax Leda C. The behavior of these new propulsion systems was examined to answer the following research question: “Which currently existing energy source(s) can be used to transport the polymetallic nodules from the Clarion-Clipperton Fracture zone to the coast of Mexico, a 2200 km route, and whose operational use is technically feasible in five years, in the most sustainable way and with the lowest costs?". To answer this research question, the following steps have been undertaken. First current technologies and their state, were analysed using technology readiness levels (TRLs). The known data was established which included the cargo, the requirements for the fleet, the total days at sea, total amount of nodules collected in one year and the buffer of the mining vessel. With this information an optimal base case was determined in terms of energy consumption and costs. The base case is a Panamax bulk carrier called the Leda C with a deadweight of 81526 dwt.Two different key performance indicators (KPIs) were set to analyse the different performance systems. These KPIs are the emission reduction per tonne collected nodules in %/tonne and the costs per tonne collected nodules in $/tonne.To examine the different propulsion systems, their performances had to be checked for this specific route. In this route analysis there is looked at the probability of the wind, which was necessary to calculate the performances of the wind assisted ship propulsion (WASP) systems. Drive trains of the different propulsion systems were schematically given and analyzed to understand which systems should be implemented for the different propulsion systems. After this, the components of each propulsion was checked, looking at their performance, sizes and costs.The costs of the total drive trains of the different propulsion systems were elaborated. Finally, three different scenarios were chosen to examine the KPIs of the different propulsions.It is concluded that the most cost-effective technology for the RE on board systems is the Flettner rotor and for the alternative fuels this is biofuel (HVO). The propulsion systems discussed in this research will only be attractive when the CO2 tax will increase. It is concluded that the higher the carbon tax, the more attractive the alternative fuels become in terms of cost effectiveness.The advice for Allseas will be, if nothing changes, to not install a sustainable energy propulsion system. Because all systems will be more expensive than the base case. If regulations make it necessary to reduce emissions, it is advised to install the Flettner rotor in hybrid with the current engine.

The Ampelmann A-type hexapod platform is a motion compensating gangway system designed to transfer offshore personnel between a crew transfer ship and an offshore bottom founded structure. During operation, the platform is moved to compensate wave induced ship motion and create a still standing platform from which crew can safely transfer to the fixed structure. The hexapod platform is actuated by six high power linear actuators each capable of delivering 150 kW of power. To reduce the platform mass and reduce the operational energy requirements of the A-type, new actuator technologies are considered to replace the current conventional hydraulic actuators. Especially electro-hydrostatic and electro-mechanical actuation are promising alternatives to reduce mass and increase efficiency. Currently, properties of these technologies are only described up to power levels of 45 kW. Relative advantages of one over the other technology are not readily available in literature for higher power requirements.
To be able to compare both actuator technologies for use in the Ampelmann A-type, a preliminary design tool is made using existing and newly developed actuator mass and power loss models. General mass and loss properties of both actuators are determined and compared to develop a better insight in the optimal high power linear actuator technology for a specific application. Insights are applied but not limited to the Ampelmann application.