Currently, our society faces a pressing challenge: global warming. The solution lies in the energy transition, which replaces fossil fuels with clean sources. This requires a global effort across all sectors, including shipping. While a significant portion of shipping relies on polluting fuels, the European Union’s Green Deal aims for climate neutrality by 2050, which applies to shipping as well. Emission reduction technology and low-to-zero emission energy supplies are emerging, yet choosing the right energy supply for new vessels remains complex, especially in meeting EU targets.
This study focuses on supporting the decision-making process for the energy supply of a new Semi-Submersible Crane Vessel (SSCV). The method facilitates a comprehensive comparison of energy supply options using multiple criteria. It also integrates decision-makers’ preferences with the characteristics of alternative energy supplies, providing insights into the most suitable choice. This research features a case study centered on Heerema Marine Contractors’ SSCV Sleipnir.
To create this method, a literature review on Multi-Criteria Decision Making (MCDM) methods was conducted. The Analytic Hierarchy Process (AHP) model was chosen as the foundational framework for the decision-making tool. During the research key limitations and requirements for designing an energy supply for a SSCV were identified. Furthermore, the research contains an examination of various fossil and sustainable fuels, including Marine Gas Oil (MGO), (E-)Liquefied Natural Gas ((E-)LNG), EHydrogen, E-Methanol, E-Ammonia, Uranium, and Thorium. Additionally, the study considers diverse energy conversion systems including Internal Combustion Engines (ICE), Proton Exchange Membrane Fuel Cells (PEMFC), Solid Oxide Fuel Cells (SOFC), Direct Methanol Fuel Cells (DMFC), Molten Salt Reactors (MSR), and Very High-Temperature Reactors (VHTR). A set of significant criteria are identified and the accompanying characteristics of the energy supplies regarding these criteria are gathered. The literature research is followed by a financial assessment. This assessment shows that the financial impact of fossil- and e-fuel energy supplies is highly dominated by Operational Expenditure (OPEX), while the nuclear energy supplies are highly dominated by its Capital Expenditures (CAPEX).
The preferences of Heerema’s decision-makers are collected via a survey, revealing that the Technological Readiness Level (TRL) of the system, health risk, emissions, Levelized Cost Of Energy (LCOE), maintenance requirements, and efficiency of the conversion system are found to be the most important criteria according to the survey results. The preference weights assigned to the criteria are integrated with the energy supply characteristics, providing a score that indicates the suitability of each energy supply considering the SSCV’s limits and requirements, aligned with the preferences of the decision-maker. Hence, the optimal energy supply choice can be deduced from this data.
Although the fossil fuel MGO is included to act as a base-case scenario during this case study, the results of the method show that MGO used in an ICE would be the best-suiting energy supply according to the preferences of the decision-makers. Since MGO energy supplies are assumed to be non-compliant with the EU-emission goals they are excluded. When excluding MGO from the results, methanol used in an ICE is identified as the best-suiting alternative. This can be attributed to its relatively high TRL, favorable overall characteristics, and absence of significantly low scores regarding the criteria assigned high priority by the decision-makers, in comparison to other energy supplies.
However, the validity of the presented results is reduced due to several factors. These include the reliance on assumptions about alternative energy supplies, a limited number of interviewees, and the sensitivity to uncertainties about future developments. Nevertheless, this study shows that the use of this method can provide insights into complex decision problems regarding future energy supply choices. Also, the study identifies a range of attractive energy supplies, with methanol used in an ICE ranked as the most suitable option. These high-ranking energy supplies can be an interesting subject for further studies.

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.

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.

The current path the marine industry is following, the goals of the Paris Agreement to reduce emissions, will not be met. The marine industry is mainly sailing on HFO and emits 2.2% of the global greenhouse gasses (GHG) by doing so, as well as 18-30% of NOx, 5-8% SOx and 11% particulate matter (PM). The IMO has even predicted that the emissions of GHG will increase between 50 and 250% if the shipping industry continues on this path. In order to reduce emissions, the International Maritime Organization (IMO) has implemented ambitious goals for the next decades. However, the current policy measures sparks low ambition to meet this IMO GHG strategy. To be able to meet this goals, four options with different potential of reducing emissions are available, viz. efficient ship hull designs (20%), energy efficient engines (10-15%), more efficient propulsion (5-20%), clean technologies such as fuel cells and the use of alternative fuels (100%). Since the alternative fuel option has the largest potential in reducing emissions, a number of researched have looked into possible options for alternative fuel, such as LNG, LPG, methanol, biofuel, hydrogen and ammonia. This thesis looks into the potential of ammonia as an alternative fuel in the marine sector by 2030 by looking into the critical success factor for the fuel.
This research takes all the aspects of the marine industry into account and researches the mutual interaction and relation between the aspects. The main aspects are the power generation options, the fuel availability including the port logistics, price of the fuel, operations (OPEX), impact on the vessel (CAPEX) and legislation and rules. These aspects have a number of inter-dependencies.
The barrier related to the power generation option is the lack of availability of an engine that can run on ammonia. This engine needs to comply with legislation, which is not implemented yet. The barrier related to the fuel itself is the availability of the fuel in both volume and location. The production capacity is not yet at a level to fuel a significant part of the marine sector. The barrier related to the port are the logistics of the supplier and storage and handling of ammonia. Ammonia is a toxic substance and requires safety measures. These rules have not been implemented either. Closely related to the availability of the fuel is the price of the fuel. This is dependent on the demand of ammonia, which is currently zero for the marine sector. For the operational aspect is the lower energy density compared to conventional fuel an important barrier. For the same energy output, a greater volume of fuel is needed. This requires either extra stop overs during the voyage or a larger fuel tank, which could lead to loss of cargo space. The larger fuel tank has an impact on the design of the vessel, as well as the different storage and handling of ammonia compared to conventional fuels. Together with the legislation, this is an important barrier for the CAPEX of the vessel. This is a very important decision factor for the ship owner. Finally, most important barriers is the legislation. This aspect has the largest influence on all the other aspect and can promote other aspects to invest in ammonia and take steps in implementation. The regulation for sailing on ammonia are not yet in place. The IMO is responsible for the IGC and IGF code that regulate fluids as cargo and as fuel. The IMO has not started working on implementing ammonia as a fuel yet, since the demand of the fuel is currently low. This is however due to the regulations not yet being in place. Ship owners are reluctant to switch to another fuel when the risk of implementing the rules incorrectly are too large. The design requirements are not yet clear and it would be too costly to refit a vessel to the correct requirements for the early adaptors. Another aspect the regulations have large impact on are the engine options. Ammonia has a narrow flammability and is more difficult to ignite compared to conventional fuels. The design of the engine needs to comply with the regulations for safe ignition.