Centre for Marine and Renewable Energy (MaREI) - Doctoral Theses
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Item A geospatial economic analysis of hydrogen production from offshore wind using electrolysers(University College Cork, 2024) Vu Dinh, Quang; Leahy, Paul; Dinh, Nguyen; Wall, David; Science Foundation IrelandThe transition to renewable energy has driven growing interest in green hydrogen as an energy carrier. Green hydrogen refers to hydrogen produced without generating carbon emissions. Typically, it’s produced from renewable energy sources. Combined with the advantages of offshore wind, green hydrogen production from offshore wind energy has emerged as a potential versatile zero-carbon energy vector. Exploiting offshore wind energy to produce hydrogen not only opens up a new direction in the use of renewable energy but also positively contributes to global sustainable development goals. A comprehensive literature review highlights advancements in green hydrogen production, geospatial methods for renewable energy, and the optimisation of hydrogen systems. This thesis focuses on researching the potential of the technical and economic aspects of hydrogen production from offshore wind energy. Two concepts for combining electrolysers with offshore wind farms to produce hydrogen are considered. In the first concept, the centralised electrolyser is located offshore, while the second considers an onshore centralised electrolyser. The first aim is to develop a model to calculate the cost of hydrogen production from offshore wind farms. Then, the cost model is used to construct a LCOH map and applied to Irish waters. The area off the west coast has more robust wind resources than the east coast. However, the east coast has shallower water depths and seaports that are more convenient. Nearshore areas suitable for cheaper foundations can produce hydrogen at a lower cost in the two hydrogen production concepts considered. The second aim is to minimise hydrogen production costs by optimising installed electrolyser capacity. In a 600 MW offshore wind farm case study, the optimal offshore electrolyser capacity is about 83% of the wind farm capacity. In the onshore electrolyser concept, the optimal ratio is about 79%. This research also conducts sensitivity analyses to examine the influence of technical parameters on the optimal electrolyser capacity, providing valuable insights into system design and operational efficiency. Beyond hydrogen production aspects, a general assessment to identify potential export markets for hydrogen from Ireland was also investigated. Countries with high hydrogen demand and close to Ireland, such as the UK, Germany, France, and the Netherlands, could be potential export markets in the future. Hydrogen trade among markets will require a suitable hydrogen transport method. Hydrogen can be transported directly or in other forms. The offshore transportation of hydrogen in the form of ammonia was investigated. From the results, suitable transportation methods can be selected based on transportation distance and electrolyser capacity. The goal of this thesis is to provide a comprehensive and in-depth view of the process and potential of hydrogen production from offshore wind energy, thereby contributing to general knowledge and supporting planners, policymakers, scientists, and engineers in promoting the application and development of green hydrogen production from offshore wind energy. The results and recommendations will be the basis for new steps in the journey towards a sustainable energy future. Sensitivity analyses demonstrate that the projections of hydrogen demand and levelised cost presented in this thesis are dependent on input data and assumptions which will need to be continually updated as the technology and markets develop.Item Experimental and numerical investigation of towing operations for large floating offshore wind farms(University College Cork, 2024) Chitteth Ramachandran, Rahul; Murphy, JimmyFloating Offshore Wind Turbines (FOWTs) represent a pivotal advancement in renewable energy technology, extending the reach of wind power to previously inaccessible waters. Their importance lies in their ability to exploit the stronger and more consistent winds in deep waters. Installing these floating platforms in sites where the weather is harsh invites significant challenges. A major challenge lies in towing these platforms from the fabrication site to the farm location. The commercialisation of floating wind aims at farm-scale deployments and installation of large wind turbines. For planning fast, cost-effective and safe towing operations, the understanding of its physics is paramount. It is also important to develop numerical methods and simulation approaches to understand and predict the motions and towing loads while towing these significant floating structures. This thesis constitutes a deep exploration of the towing operations associated with floating wind turbines, integrating a multifaceted analysis encompassing case studies, experimental tests and numerical methodologies. Semi-submersible floaters, being one of the early movers, are the main focus of this thesis. The presented thesis has followed an ‘industry-ready’ approach and aims at minimising the gap between academia and industry by attempting an equilibrium between them. The thesis is split into four research papers and starts with a literature review examining marine operations integral to floating wind turbines, identifying specific challenges and finding opportunities for synergy with other well-established and developed offshore industries such as Oil and Gas (O & G) and fixed-bottom wind industries. Towing operations, being required for installation, major repairs and decommissioning are then analysed and two numerical approaches for the hydrodynamic analysis of semi-submersible floating wind turbines are developed and implemented in two different commercial hydrodynamic analysis tools. The first method is a potential flow-based forward speed approach with corrections for viscous effects implemented in the in-house tool SEACAL. The second method is a hybrid approach utilising a potential flow method combined with the Morison equation and implemented in the commercial tool Orcaflex. The hybrid approach is also implemented in a free open-source numerical tool OpenFAST for the further development of the research work. To validate the numerical results, a detailed experimental campaign was conducted and validation data for towing in various sea conditions, towing configurations and towing speeds were generated. A comparative study of both approaches is presented and the advantages and disadvantages of the developed methods are summarised. The findings indicate that both developed numerical models possess the capability to analyse and predict towing characteristics contingent upon towing speed and prevailing wave conditions. The first method is better suited to considering low speeds (0.514 m/s–1.542 m/s) and low wave heights (1m – 2m) whilst the second method is better suited for higher speeds (0.514 m/s – 3.084 m/s) and higher wave heights (1m – 6m). Depending on the weather conditions, towing requirements and availability of the numerical tools, the suitable analysis method can be chosen.Item Depicting energy service demands as a mitigation lever in energy systems models(University College Cork, 2024) Gaur, Ankita Singh; Daly, Hannah E.; Curtis, John; Science Foundation IrelandEnergy Systems Optimisation Models (ESOMs) and Integrated Assessment Models (IAMs) are integral to informing climate change mitigation strategies and the associated policymaking processes. However, the techno-economic nature of these models restricts the representation of demand-side mitigation measures, which have been recognised to have substantial potential in meeting climate goals. Specifically, measures that can bring about a reduction in the level or structure of energy demand are often missing. Even when such measures \emph{are} included—often as exogenous scenarios—they are typically not well-connected to empirical evidence and lack spatial and demographic granularity. Moreover, these demand reduction measures are more relevant to developed countries like Ireland. In developing countries, access to energy services is disproportionately low, despite the higher growth in demand for energy relative to developed countries. Further, the representation of Global South regions is generally oversimplified in large-scale IAMs, often relying on stylised assumptions based on observations from Global North. This thesis seeks to address these gaps by adopting a dual approach of addressing demand-side mitigation while incorporating a particular perspective from the Global South region. This thesis develops bottom-up projections of energy service demand for the TIMES-Ireland Model (TIM). The baseline energy service demands are driven by growth in population and economy. TIM is set up to allow for alternate scenarios for demand drivers that result in different energy service demand projections in the end-use sectors. The thesis develops the `Irish Low Energy Demand' (ILED) scenario where the impact of reducing and restructuring energy service demand on the whole energy systems is analysed using TIM. The results indicate that the ILED pathway is especially valuable in meeting near-term deep mitigation targets and lowers reliance on novel fuels and technologies. For policymakers, the recommendation is to expand the arsenal of mitigation measures, beyond policies that promote renewable energy deployment and energy efficiency. It was observed that a pivotal driver of such Low Energy Demand (LED) scenarios both, at national and global level, is spatial settlement patterns. The LED scenarios heavily depend on future compact development. Hence, to improve the granularity and empirical basis of such scenarios, this thesis quantifies the relationship between population density and the energy as well as carbon intensity of the residential and transport energy service demands. Analysis reveals that the energy and carbon intensity of populations living in dense parts of Ireland are significantly lower than those living in sparsely populated areas. The future growth of cities and town in Ireland, whether compact or dispersed, will heavily determine emissions trajectory and mitigation options. This exercise allows future modelling studies to include spatial settlement patterns as a mitigation lever. This thesis also analyses the impact of electrifying spatially dispersed residential heating demand on the Irish power system. This analysis is particularly important for Ireland: given the lack of a district heating network, electrification is the central heat decarbonisation policy. Utilizing a generation and transmission expansion planning model, the analysis finds that the spatial distribution of demand drives the investments in the power system. This again highlights the role of future spatial settlement patterns in decarbonising the Irish energy system. Further, electrifying residential heating via heat pumps leads to greater utilization of renewable energy, when combined with thermal energy storage. In the next part, this thesis explores the gaps and challenges associated with representing Global South regions in a global IAM. With a focus on passenger mobility in South Asian countries, this thesis develops an evidence based framework to improve the quantification of sustainable mobility scenarios in global IAMs. A comprehensive literature review is conducted to identify measured causal relationship between various phenomena, such as urbanisation and passenger mobility patterns, placing an emphasis on literature focusing on South Asia and the Global South. These phenomena are incorporated into a novel mobility projection model designed to interface with an IAM. This is an innovative and adaptable framework, that can be applied to other Global South regions and other IAMs. Using this framework, four distinct mobility scenarios are developed, each reflecting alternate visions for mobility based on explicit futures for these phenomena. Through the various research chapters, this thesis demonstrates the value of including demand-side measures in ESOMs and IAMs. It highlights how energy service demands can be managed to reduce GHG emissions, particularly in the residential and transport sectors. Further, by incorporating empirical evidence of the phenomena that drive energy service demands, the research develops methodologies to improve the quantification of decarbonisation scenarios in ESOMs and IAMs. And lastly, the inclusion of region-specific data for the Global South is a step towards more equitable practices within IAM frameworks.Item Integrating air quality modelling, low-cost sensing and greenspace quantification for enhanced urban air quality and net-zero cities(University College Cork, 2024) O'Regan, Anna Claire; Nyhan, Marguerite; Hellebust, Stig; O'Dowd, Colin; SFI Research Centre for Energy, Climate and Marine; University College CorkUrbanisation is rapidly increasing worldwide. Currently, 55% of the global population live in urban areas and this is projected to increase to 70% by 2050. While urban areas are sites for innovation and economic growth, they are also key hotspots for poor air quality and climate-related impacts. Air pollution poses a significant risk to public health, with 96% of urban populations exposed to unhealthy levels of air pollution. As such, data on urban air quality is essential to identify pollution sources as well as spatial and temporal trends. This can support the formation of policies, ensuring compliance with regulatory limits while striving to meet the stringent World Health Organization (WHO) guidelines to protect public health. Air pollution and greenhouse gas (GHG) emissions often stem from common sources. Consequently, there is significant potential to develop policies that enhance air quality while also maximising reductions in GHG emissions. Rapid urban expansion is significantly impacting greenspace, with a notable decline observed due to increased demand for grey infrastructure. Greenspace offers many environmental benefits, including reducing air pollution and mitigating against the impacts of climate change, while also positively influencing residents’ health. As such, prioritising strategic greenspace developments is crucial. This research is driven by a need to improve our understanding of air pollution, greenspace and their associations, with an overarching aim of decarbonising cities. Firstly, a comprehensive review of global literature was conducted, identifying the current state-of-the-art in air pollution and GHG emissions modelling and monitoring efforts. Furthermore, innovative methods for quantifying urban greenspace were explored. Air pollution, specifically nitrogen dioxide (NO2), was modelled in high spatial and temporal resolution for Cork City, Ireland. The output of the dispersion model enables the identification of pollution sources while also capturing fluctuations in pollution levels over time and space. Moreover, a data fusion technique, regression kriging, was employed which integrated the urban dispersion model output with large-scale citizen science data. The citizen science data was measured using diffusion tubes at 642 locations across the study domain. The data-fusion model provided improved accuracy of air pollution levels and population exposure. Urban greenspace was quantified using 751,644 Google Street View (GSV) images, capturing a street-level view of greenspace at 125,274 locations across three major cities in Ireland. The associations between street-level greenspace, health and socioeconomics were explored. Higher levels of greenspace were associated with improved self-reported health and areas in the upper quartiles of greenspace had higher levels of income and lower levels of unemployment. Furthermore, with the advancements in air pollution sensing technologies such as ‘low-cost’ sensors, this research aimed to explore the relationship between greenspace and air pollution. This analysis demonstrated associations between higher levels of greenspace and lower levels of air pollution in urban areas. This research provides novel contributions across science and policy. It advances scientific knowledge and methodologies in air quality science and urban greenspace. Moreover, the research findings and high-resolution datasets can inform data-driven policies such as the National Clean Air Strategy (CAS) and Climate Action Plan, while also advancing UN Sustainable Development Goals including ‘Goal 11: Sustainable Cities and Communities’, ‘Goal 3: Good Health and Wellbeing’ and ‘Goal 13: Climate Action’. There is great potential to design effective strategies that strive to improve air quality and ensure optimal planning and provision of greenspace, thereby accelerating the transition to net-zero. Adopting an integrated approach in urban planning will ensure the development of cities that have good air quality, ample exposure to greenspace and net-zero emissions.Item Nurturing blue growth: enabling sustainable development of emerging marine sectors(University College Cork, 2024) Giannoumis, Jessica; Wheeler, Andrew; Dooley, Lawrence; Cummins, ValerieCurrent marine resource exploitation practices and management are unsustainable as resource degradation is ongoing and coastal regions struggle to realise sustainable development of marine resources. The key topic of this research is expanding knowledge on the reconciliation of environmental and economic models regarding the sustainable development of marine resources through the EU-introduced concept of blue growth. In the context of this research, blue growth refers to the sustainable development of marine resources, generating livelihoods, and securing well-being from innovation in emerging marine sectors. Blue growth development attracted interest across Europe and beyond, as the utilisation of marine resources is viewed as an opportunity to meet climate change obligations, enable a transition away from finite resources, and creating employment opportunities, thereby enabling long-term regional economic development. Blue growth development initially focused on the development of five emerging marine sectors with economic growth potential including coastal tourism, aquaculture, ocean renewable energy including offshore wind development, seabed mining, and marine biotechnology. Yet, EU coastal regions struggle with the realisation of blue growth as they received limited guidance from the European Commission on what blue growth is and what successful blue growth development looks like. This highlights a need to investigate what nurtures blue growth to enable coastal regions to realise their blue growth potential. This qualitative and interdisciplinary research focuses on the potential of blue growth in coastal regions focusing on the development of emerging marine sectors. In the context of this research, a region refers to coastal regions with common economic activities and characteristics, such as access to regionally specific marine resources, and common administrative characteristics such as specific political and governmental functions, e.g., regional economic development policies. Within the scope of this research, emerging sectors refer to rapidly growing industries utilising innovative technologies to enable sustainable development of regions, job creation, and technological advancement. This research investigates the manifestation and effectiveness of an EU intervention, the ProtoAtlantic project which includes regions of Orkney (SCT), Cork (IRE), Brest (FR), Porto (PT), and Las Palmas (SP) and two in-depth cases in Norway and Scotland. ProtoAtlantic was a Interreg Atlantic Area project, initially funded from November 2017 to October 2020, due to Covid-19, the project was extended to October 2021. The study harnessed an opportunity to engage with a wide range of multiple stakeholders representing stakeholders from government, industry, and academia. Data collection from the ProtoAtlantic cases included extensive desktop research and policy analysis of marine and generic development strategies in each case, analysis of regional blue growth stakeholder workshops which were carried out in each region, as well as analysis of additional material provided through the ProtoAtlantic project such as the outcomes of the ProtoAtlantic accelerator programme, and semi-structured interviews with nine regional stakeholders. The two deep dive cases included the offshore wind sector development around the DeepWind cluster in Scotland and the Norwegian aquaculture sector. Data collection from the in-depth cases included extensive desktop research and policy analysis of marine development strategies with particular focus on offshore wind development in Scotland and aquaculture development in Norway, in addition to 32 semi-structured interviews. To date, limited scientific attention has been paid to blue growth realisation from a marine governance perspective. Even less research has been undertaken to understand blue growth development from a business perspective. The research aim was to expand on how economic opportunities can catalyse sustainable development in a marine context. By achieving economic sustainability, coastal communities may consequently be in a better position to achieve environmental and social sustainability. The findings of this research address this research gap and provide practical contributions on how decisionmakers in coastal regions can nurture and realise their regional blue growth potential. In-depth analysis found that blue growth requires a systems approach which enables the integration of blue growth antecedents, this has been lacking from current marine management approaches. Furthermore, the study found that economic development approaches to marine resource management can secure well-being of coastal communities and ensure sustainable practices to marine resource utilisation. This research offers a modification of Ostrom’s Social-Ecological Systems framework, the expansions of the framework provide insight into collective action, the role of technology development, and the need for bespoke regional approaches to identify and realise blue growth. This research examines the role of regional stakeholders, the need for entrepreneurial activity and clustering activities in driving blue growth development and offers recommendations for policymakers and decisionmakers in coastal regions to nurture blue growth adoption and development. This research also presents a Practitioner’s Guide to Blue Growth which offers relevant questions to enable practitioners and intermediaries in the identification and realisation of their regional blue growth potential.