Global climate change, which is largely attributed to human activity, is one of the foremost challenges of the 21st century. In recent times, there have been notable alterations in the Earth's climate, resulting in profound impacts on ecosystems and biodiversity. These alterations are caused by greenhouse gas, such as carbon dioxide, methane, and nitrous oxide. Greenhouse gas emissions are caused by practices such as deforestation, industrial operations, and the combustion of fossil fuels in vehicles, vessels, aircraft, and manufacturing facilities. The maritime and aviation industry is currently responsible for approximately 6% of global greenhouse gas emissions. Due to logistical and economic constraints, these industries are heavily reliant on liquid fuels, making direct electrification options unavailable for large parts of these sectors. As a result, these sectors are considered ‘hard to abate’. Understanding the future climate mitigation challenges associated with the maritime and aviation sectors is crucial in shaping effective policy measures, avoiding stranded assets, and preserving the chance to meet Paris Agreement-compatible emission reduction pathways.
This thesis identifies three main challenges and proposes modelling approaches to address them when modelling decarbonization pathways for the aviation and maritime sectors. From these challenges, research gaps have been identified that this PhD thesis aims to fill. Three models have been developed for the thesis: a maritime optimization model, a maritime demand model, and an aviation demand model. The modelling landscape and methodology vary across models, ranging from econometrics and data science to mathematical optimization.
To overcome the challenges and fill in the research gaps, three corresponding modelling approaches have been successfully applied:
1. Developing a holistic decarbonization modelling landscape. This includes life-cycle representations of technology costs and emissions, the upscaling of bottleneck technologies, the availability of sustainable biomass, and consideration of competing demand from other industries, as well as representations of policy levers such as carbon pricing or improvements to fuel efficiency.
2. Developing demand models that interpret the underlying scenario narrative consistently (SSP framework).
3. Improving the representation of technological learning for low-carbon technologies in energy system models.
The findings acquired by applying these three modelling approaches are valuable for energy modellers, climate scientists, and policymakers and offer unique insights into the inherent system dynamics associated with decarbonization of hard-to-abate sectors. Utilizing this modelling landscape reveals that current decarbonization efforts for hard-to-abate sectors are insufficient.
Physical wave basin tests with a focus on uncertainty estimation have been conducted on a sphere subjected to wave loads at Aalborg University as part of the effort of the OES Wave Energy Converters Modeling Verification and Validation (formerly, OES Task 10) working group to increase credibility of numerical modeling of WECs. The tests are referred to as the Kramer Sphere Cases, and the present note is dealing with wave excitation force tests on a fixed model. The present note is including details to facilitate CFD models which replicate the physical setup in detail.
Maritime transportation is an essential pillar of modern societies, serving as the backbone of global trade. The shipping industry relies heavily on fossil fuels, significantly impacting the environment and contributing to climate change. The International Maritime Organization (IMO) has introduced a strategy to reduce greenhouse gas emissions from international shipping and decarbonize the industry to combat this issue. This strategy aims to accomplish energy efficiency gains, transition to alternative fuels, and implement market-based measures.
Various energy efficiency indicators are in use to monitor the performance of ships, both from technical and operational perspectives. Building upon previous research that identified shortcomings in these indicators, this thesis investigates alternative methods of assessing the energy efficiency of ships. Emphasizing the importance of a benchmarking tool, the primary objective of this thesis is to contribute to the policy debate on reducing emissions in international shipping by developing a comprehensive carbon intensity indicator.
The thesis comprises four articles addressing various approaches to monitoring ship carbon emissions. The first article focuses on the influence of weather conditions on a ship’s energy efficiency, thereby contributing to the ongoing discussion on weather correction factors. Using model-based machine learning techniques, this article illustrates the diverse sea conditions encountered, their impact on energy efficiency, and the necessity of accounting for this diversity through multiple correction factors.
The second and third articles introduce and develop the concept of operational cycles for maritime transportation, drawing inspiration from the driving cycles employed in the automotive industry. The second article describes the process of generating operational cycles for the maritime sector as a novel concept. It validates this concept using real-world data obtained from a fleet of container ships. Building upon this foundation, the third article extends the concept by elaborating more comprehensive cycles that better represent real-world indicators.
The fourth article explores voluntary reporting frameworks in the shipping industry. It focuses on the Clean Cargo case and investigates the needs and interests of its members regarding this private initiative and related reporting framework. The discussion revolves around the role of these voluntary frameworks as complementary approaches to regulatory frameworks towards maritime decarbonization.
Based on the methodology developments and analysis through the thesis, the following key findings and recommendations are presented:
• The weather impact on ships’ fuel consumption prevents an accurate and real assessment of ships’ efficiency. Multiple weather correction factors for energy efficiency indicators introduce a novel approach.
• Inspired by the automotive industry, maritime operational cycles improve the assessment of technical and operational aspects of a ship’s energy efficiency. The cycles reduce the variability inherent to energy
efficiency indicators and are suitable as benchmarking tools.
• Although the IMO regulatory framework remains at the core of the maritime decarbonization strategy, regional regulatory frameworks and private initiatives have demonstrated their capacity to enhance industry
practices and facilitate regulatory developments.
This thesis contributes to enhancing carbon emissions monitoring in the maritime industry by introducing new methodologies and assessments. The resulting proposals are designed to enrich ongoing discussions within the IMO and complement the existing regulatory frameworks.
A crucial component for unmanned underwater vehicles (UUVs), including remotely operated vehicles (ROVs) and autonomous underwater vehicles (AUVs), are the thrusters, which, in addition, are sensitive to damage during operations in harsh environments. This paper presents a study on the impact of incipient faults on the performance of thruster propellers used in offshore operations. The study evaluates the reduction in propeller performance due to wear and tear under realistic working conditions. The study employs a combination of experimental data analysis and signal processing techniques, including fast Fourier transforms and harmonics analysis, to identify faults and assess their severity. The results show that worn propellers can be identified through 5th-order harmonics and rotational velocity changes. The paper concludes with a proposal for future research using a model-based approach to enhance fault detection capabilities further.
The European Green Deal (EGD) adopted in December 2019 seeks to facilitate the transition of the EU towards a climate-neutral continent and a modern, resource-efficient, and competitive economy by 2050. In addition to a set of objectives, it is also a policy program that will affect the policy landscape, by driving the development of new directives and regulation, and the amendment of existing ones. In order to facilitate a transition of EU society to better protect the marine environment, decision making and implementation processes within marine governance will need to be improved to develop and implement measures through which EGD marine protection objectives will be achieved.
The Horizon Europe PERMAGOV project aims to improve the implementation and performance of EU marine policies to reach the goals set in the EGD. The PERMAGOV project focuses on four issue areas, so-called regime complexes: Maritime Transport, Marine Energy, Marine Life and Marine Plastics. Within each regime complex, 2 to 3 case studies are used to explore and analyse how governance arrangements are emerging and changing and improving their performance through the EGD. These case studies span three European Seas, the Baltic Sea, the Mediterranean Sea and the North East Atlantic.
Containerfartens historiske udvikling bliver i litteraturen beskrevet som en revolution og en transformation af den internationale shippingbranche. De teknologiske og organisatoriske forandringer af livet til søs som fulgte med containerfarten har tilsvarende medført en forandring af maritime kulturer og en udfordring af de søfarendes identiteter.
Denne afhandling handler om danske containersøfolks erindringer, fortidsbrug og identitetskonstruktioner og undersøger, hvordan søfolkene fortæller sig selv i relation til deres levede erfaringer i containerfarten. Jeg analyserer i afhandlingen søfolkenes retrospektive fortidsfortolkninger som en måde at nærme mig en forståelse af de forandrede sømandsidentiteter.
Analytisk anlægger afhandlingen et subjektperspektiv, som anser fortiden for nærværende og åben i de mundtlige fortællingers fortolkninger og meningsforhandlinger af fortidens erfaringer. Jeg anskuer den narrative konstruktion af den personlige, autobiografiske, historie som identitetsdannende fortidsbrug, der udtrykker fortællerens subjektivitet. Med en erindringshistorisk tilgang til søfolkenes mundtlige fortællinger undersøger jeg, hvordan vi mennesker forstår os selv gennem de historier, vi fortæller om os selv.
Afhandlingen bygger empirisk på en række dybdegående oral history interviews med danske søfolk, der alle har erfaring inden for den internationale containerfart.
I afhandlingens analyser, viser jeg, hvordan søfolkene retfærdiggør og legitimerer deres valg om i første omgang at blive søfolk og senere at arbejde ombord på containerskibe. Jeg viser, hvordan søfolkene narrativt forhandler forskellige former for erfaret meningstab og aktivt tilskriver arbejdet og fællesskabet ombord på skibene en ny og brugbar mening. Jeg viser samtidig, hvordan den personlige historie konstrueres i dialog med kulturelt dominerende forestillinger og fortællinger. Sådanne forestillinger og fortællinger tilbyder den enkelte fortæller et tilgængeligt sprog at udtrykke sine personlige erfaringer i, men kan også virke begrænsende, hvis fortællerens erfaringer og forståelser ikke passer ind i de dominerende billeder. I sådanne tilfælde kan der opstå, hvad afhandlingen kalder en form for narrativt ubehag (discomposure), der kommer til udtryk som frustration og brud i fortællingens narrative sammenhæng.
Som en gennemgående metodisk pointe viser afhandlingen, hvordan interviewets intersubjektivitet er med til at forme den historie, som fortælles. Det personlige møde mellem fortæller og historiker og interviewets kulturelle kontekster indvirker på forskellig vis på den konstruerede historie. Fremfor at hævde en neutral og objektiv interviewsituation, tager afhandlingen i stedet konsekvensen af denne intersubjektivitet og skriver det konkrete møde mellem søfolkene som fortællere og mig som interviewer ind som en integreret del af den historiske fremstilling. Dette er både et narrativt greb og et metodisk valg, der skal sikre transparens ved at give læseren indblik i, hvordan historierne og mine tolkninger er blevet til.
Afhandlingen yder med sin tilgang og sine analyser flere bidrag til den eksisterende litteratur. Gennem de personlige fortællinger får vi større indsigt i søfolkenes levede liv og deres erfaringer med containerfartens historiske udvikling. Afhandlingen giver et menneskeligt perspektiv på historien om den internationale containerfart, der bidrager til vores viden om udviklingens identitetsmæssige betydning for de mænd og kvinder, som gennemlevede de historiske forandringer ude ombord på skibene.
Afhandlingen er en virksomhedshistorie, der tager oral history alvorligt både som forskningsfelt, metode og genre. Afhandlingen bidrager med sin erindringshistoriske tilgang til oral history til den fornyede samtale mellem forskningsfelterne oral history og virksomhedshistorie. Afhandlingen bringer metodiske og teoretiske indsigter fra den erindringshistoriske tradition ind i virksomhedshistorie og viser gennem sin egen narrative stil potentialet i en historieformidling, der sætter subjektivitet og erindring i centrum af sin analyse. Dermed bidrager afhandlingen også til den narrative vending inden for virksomhedshistorie ved ikke kun at anlægge et narrativt blik på de danske søfolks fortællinger men ved også at tage sig selv alvorligt som narrativ konstruktion.
The emissions of the maritime sector caused by ship transportation and other fossil fuel sources pose a threat to the environment and human health. It drives an increasing interest in adopting electrification solutions to revolutionize the conventional maritime energy-intensive and highly polluting industry. Accordingly, this thesis is one of the pioneering attempts to implement a seaport microgrid and carbon capture shore power system of cold ironing at a port dedicated to sustainability while remaining competitive.
However, the technological and research gaps of the conventional port scheduling paradigm constitute challenges in a synergy between the two prominent maritime electrification systems of seaport microgrids and cold ironing. The incorporation of cold ironing into seaport operations introduces new challenges to handling workflow and the potential impact of such integration has not yet been quantitatively addressed. Developing strategic management to improve port performance is always an issue for the port operators. This research gap motivated this study to develop an integrated operation and energy management framework by executing forecasting and optimization techniques for coordinating these technologies toward the emission neutrality goal.
This thesis begins with an extensive review of the significant aspects of cold ironing technology and seaport microgrids. A range of factors associated with the varying demand for cold ironing in seaport microgrids, requiring advanced forecasting techniques, are described in Chapter 2. Another challenge is that the integration of cold ironing with limited capacities increases the complexity of the existing seaside operation at port namely the berth allocation problem (BAP) and quay crane allocation problem (QCAP). It prolongs the waiting time for the ships to be served at berth. Thus, a seaside operational optimization model is developed in Chapter 3 to cooperatively schedule BAP, QCAP, and cold ironing assignment problems (CIAP). Chapter 4 integrates bilevel optimization as an energy management system (EMS) framework to coordinate the joint cold ironing with the seaport microgrid concept, providing more flexibility in energy scheduling while remaining cost-effective. Finally, Chapter 5 presents the overall conclusions of the thesis, research contribution, and future recommendations.
This PhD thesis presents a numerical solution of the hydroelastic problems encountered especially by large flexible ships sailing in waves. The solution is implemented by extending an existing seakeeping tool (OceanWave3D-seakeeping) to allow for the efficient and accurate evaluation of the hydroelastic response of ships. OceanWave3D-seakeeping has been developed by the Maritime Group at DTU-Construct based on solving the linearized potential flow theory using high-order finite differences on overlapping curvilinear boundary-fitted grids. Modal superposition is employed to couple the hydrodynamic and structural analysis of ships at both zero and non-zero forward speed. The ship girder is approximated by an Euler-Bernoulli or a Timoshenko beam, and the vertical bending deformation is mainly considered in this work. The shear effects on the hydroelastic response are also investigated in the Timoshenko beam approximation. The solution has been validated against experimental measurements and reference numerical solutions for several test cases. The correct computation of the hydrostatic stiffness, structural stiffness and hydrodynamic forces is the key to the
accurate prediction of the hydroelastic response, and these three terms are discussed deeply in this thesis.
With respect to the hydrostatic stiffness model, some controversy has long existed in the literature about its correct form for elastic motion modes, with Newman [1] and Malenica [2] arriving at different forms which are respectively defined in earthand body-fixed reference systems. In this thesis a complete derivation of both forms including the buoyancy and gravitational terms is provided, and the equivalence of the two models associated with elastic motions is confirmed.
A finite element method (FEM) is a common way to compute the structural stiffness of ship hulls. However, for large modern ships, a FEM calculation based on a full structure is inevitably time-consuming since distinguished differences between the longitudinal and the cross-sectional scales of ship hulls usually exist, and the sectional configurations are generally complex, bringing difficulties to numerical modeling. Considering that the structure of modern ships (for example container ships), is usually nearly periodic in the longitudinal direction, in this thesis the ship hull is approximated as a periodic beam and a new implementation of asymptotic homogenization (NIAH) is introduced to efficiently calculate the structural stiffness. This can greatly improve the computational efficiency compared with a full FEM model. Several test cases with both solid and thin-walled sections are given to validate the proposed technique. A range of representative mid-ship sections for a container ship are also considered to investigate the influence of stiffeners on the hydroelastic response.
In the hydrodynamic part, zero-speed and forward-speed radiation and diffraction problems including the well-known m−terms in the body boundary conditions, have both been solved. For generalized modes, the boundary conditions using the corresponding generalized m−terms are applied in the calculation. Neumann-Kelvin (NK) and double-body (DB) linearization models are applied as the steady base flow, and their performance is investigated by comparison with experimental measurements. In head seas, the influence of increasing forward speed on the resonant response of the flexible modes is also studied.
Through the integration of hydroelastic analysis using potential flow theory, and advanced numerical techniques, this thesis contributes to a deeper understanding of the complex interaction between flexible ship hulls and ocean waves, offering valuable insights for the maritime industry.
Determination of coverage and thickness of marine growth is a useful tool for determining structural loads and drags on marine structures and ships. In this work, we present an algorithmic program based on sonar and optical camera measurements, that estimates both the coverage and thickness of marine-fouling on off-shore structures. The marine-fouling composition is estimated using a Deep-Neural Network, trained using supervised methods, which can distinguish between hard/soft fouling species and the background water and structural components. The marine-fouling thickness is estimated using an HF Forward Looking Sonar, which is applied as a sensitive ultrasonic thickness gauge, when combined with a thickness measurement algorithm. Combined the measurements provide a localized estimate of the marine-fouling coverage and loadings across the structural surfaces, which can be used for automatic inspection evaluation and mission planning.
This report provides public recommendations for waterborne transport to West Coast of Norway, with the focus on the specified transport system in use case A in the AEGIS project. The complete background for this report is only achieved by reading all the other deliverables related to the use case, however these are confidential. Therefore, it is recommended to read the ICMASS 2022 paper "Development of an advanced, efficient and green intermodal system with autonomous inland and short sea shipping – AEGIS"1 to get a better overview of the project and specifically use case A. The transport system of use case A consists of mother vessel(s) together with one or more daughter vessels, connected by several ports. The mother vessel transports containers from Rotterdam via Hitra Kysthavn and into ports in the Trondheimsfjorden. The rationale for this use case is to enable a more flexible and cost-efficient waterborne transport solution for fjords and smaller ports.