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Aquest ítem conté el treball original, així com una versió millorada del mateix a posteriori, Tot i que no hi ha cap projecte comercial d'energia eòlica flotant en funcionament, actualment el sector eòlic flotant està creixent significativament. La situació actual pel que fa la necessitat de reduir les emissions de carboni, l'alt potencial del recurs eòlic en aigües profundes, i les menors restriccions d'ús del sòl, impacte visual i soroll, fan de l’eòlica flotant una tecnologia molt atractiva. No obstant, encara es desconeix molt sobre els efectes sobre el medi ambient. En aquest treball es presenta el potencial d'escalfament global de l'eòlica marina flotant seguint la metodologia d'avaluació del cicle de vida, a més, es comenten diferents impactes ambientals descrits a la literatura. L'objectiu principal d'aquest treball és analitzar les emissions específiques de CO2 per a totes les zones viables a tot el món en funció de les condicions del lloc; distància a la costa, distància al port, profunditat de l'aigua, alçada significativa de les onades i potencial eòlic. Els resultats mostren moltes zones amb valors inferiors a 15 kgCO2eq/MWh, localitzades principalment a països del nord d'Europa, Amèrica del Sud, Egipte, Vietnam, Nova Zelanda, etc. i mostra una baixa intensitat de carboni en comparació amb altres tecnologies que són altament implementades en l’actualitat., Aunque no existe ningún proyecto comercial de energía eólica flotante en funcionamiento, actualmente el sector eólico flotante está creciendo significativamente. La situación actual en cuanto a la necesidad de reducir las emisiones de carbono, el alto potencial del recurso eólico en aguas profundas, y las menores restricciones de uso del suelo, impacto visual y ruido, hacen de la eólica flotante una tecnología muy atractiva. Sin embargo, aún se desconoce mucho sobre los efectos sobre el medio ambiente. En este trabajo se presenta el potencial de calentamiento global de la eólica marina flotante siguiendo la metodología de evaluación del ciclo de vida; además, se comentan diferentes impactos ambientales descritos en la literatura. El objetivo principal de este trabajo es analizar las emisiones específicas de CO2 para todas las zonas viables en todo el mundo en función de las condiciones del sitio; distancia a la costa, distancia al puerto, profundidad del agua, altura significativa de las olas y potencial eólico. Los resultados muestran muchas zonas con valores inferiores a 15 kgCO2eq/MWh, localizadas principalmente en países del norte de Europa, Sudamérica, Egipto, Vietnam, Nueva Zelanda, etc. y muestra una baja intensidad de carbono en comparación con otras tecnologías que son altamente implementadas en la actualidad., Although there are no floating wind energy commercial projects in operation, the offshore floating wind sector is now growing significantly. The current situation about the necessity to reduce the carbon emissions, the high potential of the wind resource in offshore deep waters, and the fewer restrictions regarding land use, visual impact and noise, make floating wind a very attractive technology. However, there is still much that is unknown about the effects on the environment. In this work, the global warming potential of floating offshore wind (FOW) is presented following the life cycle assessment (LCA) methodology, furthermore, different environmental impacts described in the literature are commented. The main aim of this work is to analyse the specific emissions of CO2 for all suitable areas worldwide depending on site conditions; distance to shore, distance to port, water depth, significant wave height and wind potential. Its results show a lot of zones with values below 15 kgCO2eq/MWh, located mainly in countries of north Europe, South America, Egypt, Vietnam, New Zealand, etc. and show a low carbon intensity compared with other technologies that are highly implemented in the actuality.

En línia amb la política europea de reducció progressiva de les emissions de gasos d'efecte d'hivernacle i amb els objectius establerts en l'Acord de París, Espanya té la meta d'aconseguir la neutralitat d'emissions entre 2050 i 2100. Per a això, és imprescindible un canvi del model energètic d'Espanya, mitjançant el desenvolupament d'un parc de generació elèctrica basat exclusivament en energies renovables. Aquest nou model té com a fi aconseguir fins al 90-100% d'origen renovable en 2050, per al que s'estima necessari instal·lar entre 145-201 GW de generació elèctrica renovable, així com la capacitat de suport suficient per a garantir la seguretat de subministrament. Com a part d'aquest nou model energètic, tant el Pla Nacional Integrat d'Energia i Clima (PNIEC) 2021- 2030, com la Llei de Canvi Climàtic i Transició Energètica contemplen el desenvolupament de l'energia eòlica marina. L'aplicació d'aquesta mena d'energia està delimitada pels Plans d'Ordenació de l'Espai Marítim (POEM), recentment aprovats, que són una eina que pretén facilitar el desenvolupament sostenible de l'espai marítim, i que limita els usos i activitats que requereixen de la seva utilització, ja sigui de manera temporal o permanent. En aquest context, el present estudi abordarà una anàlisi preliminar de la viabilitat d'instal·lació de parcs eòlics marins en zones fora del POEM, avaluant per a això el potencial eòlic i els principals criteris que determinen la idoneïtat d'un emplaçament per a aquesta mena d'instal·lació (característiques naturals del fons marí i la costa, connectivitat amb la xarxa elèctrica, interferència amb altres usos del litoral i la mar, etc.). Com a resultat d'aquest, es durà a terme la delimitació d'un conjunt de zones òptimes per al desenvolupament de plantes eòliques marines, així com la identificació dels factors limitants que han de ser objecte d'una anàlisi més detallada., En línea con la política europea de reducción progresiva de las emisiones de gases de efecto invernadero y con los objetivos establecidos en el Acuerdo de París, España tiene la meta de alcanzar la neutralidad de emisiones entre 2050 y 2100. Para ello, es imprescindible un cambio del modelo energético de España, mediante el desarrollo de un parque de generación eléctrica basado exclusivamente en energías renovables. Este nuevo modelo tiene como fin alcanzar hasta el 90-100% de origen renovable en 2050, para lo que se estima necesario instalar entre 145-201 GW de generación eléctrica renovable, así como la capacidad de respaldo suficiente para garantizar la seguridad de suministro. Como parte de este nuevo modelo energético, tanto el Plan Nacional Integrado de Energía y Clima (PNIEC) 2021- 2030, como la Ley de Cambio Climático y Transición Energética contemplan el desarrollo de la energía eólica marina. La aplicación de este tipo de energía está delimitada por los Planes de Ordenación del Espacio Marítimo (POEM), recientemente aprobados, que son una herramienta que pretende facilitar el desarrollo sostenible del espacio marítimo, y que limita los usos y actividades que requieren de su utilización, ya sea de manera temporal o permanente. En este contexto, el presente estudio abordará un análisis preliminar de la viabilidad de instalación de parques eólicos marinos en zonas fuera del POEM, evaluando para ello el potencial eólico y los principales criterios que determinan la idoneidad de un emplazamiento para este tipo de instalación (características naturales del fondo marino y la costa, conectividad con la red eléctrica, interferencia con otros usos del litoral y el mar, etc.). Como resultado del mismo, se llevará a cabo la delimitación de un conjunto de zonas óptimas para el desarrollo de plantas eólicas marinas, así como la identificación de los factores limitantes que deben ser objeto de un análisis más pormenorizado., In line with the European policy of progressive reduction of greenhouse gas emissions and with the objectives established in the Paris Agreement, Spain has the goal of achieving emissions neutrality between 2050 and 2100. To achieve this, a change in Spain's energy model is essential, through the development of an electricity generation park based exclusively on renewable energies. This new model aims to reach 90-100% of renewable sources by 2050, for which it is estimated to be necessary to install between 145-201 GW of renewable electricity generation, as well as sufficient back-up capacity to guarantee security of supply. As part of this new energy model, both the National Integrated Energy and Climate Plan (PNIEC) 2021- 2030 and the Climate Change and Energy Transition Law contemplate the development of offshore wind energy. The application of this type of energy is delimited by the Maritime Space Management Plans (POEM), still under development, which are a tool that aims to facilitate the sustainable development of the maritime space, and limits the uses and activities that require its use, either temporarily or permanently. In this context, this study will address a preliminary analysis of the feasibility of installing offshore wind farms in areas outside the POEM, evaluating the wind potential and the main criteria that determine the suitability of a site for this type of installation (natural characteristics of the seabed and the coast, connectivity with the electricity grid, interference with other uses of the coast and the sea, etc.). As a result, the delimitation of a set of optimal areas for the development of offshore wind farms will be carried out, as well as the identification of the limiting factors that should be subject to a more detailed analysis.

Physical model testing is a crucial step in the validation process of floating offshore wind concepts that can be used to contribute to the worldwide decarbonization objectives. It is also important to understand the coupled performance of all the sub-systems that conform to a floating wind concept: wind turbines, mooring systems or floating platform hydrodynamic responses. Few experimental tests had been conducted, and no real-time hybrid modelling had been performed in these tests. In this paper, an open-source experimental dataset is presented, and the dynamics of a concrete spar-based floating concept withstanding the IEA 15-MW Reference Wind Turbine are investigated. An experiment on a 1:55 scale concrete-based spar (WindCrete) at IHCantabria's ocean basin was developed by means of the hardware-in-the-loop technique under the COREWIND EU-H2020 project. The available data consist of the hydrodynamic characterizations and seakeeping tests with a total of 57 available datasets. The proper behaviour of the WindCrete platform and the designed mooring system is confirmed by the maximum motion values and accelerations below the established acceptance criteria defined. Moreover, this test program identifies the importance of the wind loads over the dynamic performance of the concept., Postprint (published version)

En el presente trabajo de fin de grado, se presenta una propuesta de diseño de una turbina eólica de eje vertical offshore. Este tipo de aerogeneradores ofrecen una alternativa prometedora a las turbinas de eje horizontal en el ámbito marino. el estudio incluye el diseño de la geometría y estructura de los álabes del rotor; así como el análisis estructural de este, adaptado a las condiciones marinas de la ubicación seleccionada. Dentro de la fase de diseño, se incluye el diseño del escantillonado de la sección y una propuesta de fabricación del mismo a partir de materiales compuestos. Paralelamente, se realiza un análisis modal del conjunto rotor para la evaluación del fenómeno de la resonancia en el sistema. por otra parte, se estudia el comportamiento en la mar del conjunto formado por el rotor definido y la plataforma oc4, desarrollada por nrel. Los resultados obtenidos se comparan con los efectos producidos, bajo las mismas condiciones, en una turbina de eje horizontal.

This paper provides a summary of the work done within Phase IV of the Offshore Code Comparison Collaboration, Continued with Correlation and unCertainty (OC6) project, under International Energy Agency Wind Technology Collaboration Programme Task 30. This phase focused on validating the loading on and motion of a novel floating offshore wind system. Numerical models of a 3.6¿MW horizontal-axis wind turbine atop the TetraSpar floating support structure were compared using measurement data from a 1:43-Froude-scale test performed in the University of Maine's Alfond Wind–Wave (W2) Ocean Engineering Laboratory. Participants in the project ran a series of simulations, including system equilibrium, surge offsets, free-decay tests, wind-only conditions, wave-only conditions, and a combination of wind and wave conditions. Validation of the models was performed by comparing the aerodynamic loading, floating support structure motion, tower base loading, mooring line tensions, and keel line tensions. The results show a relatively good estimation of the aerodynamic loading and a reasonable estimation of the platform motion and tower base fore–aft bending moment. However, there is a significant dispersion in the dynamic loading for the upwind mooring line. Very good agreement was observed between most of the numerical models and the experiment for the keel line tensions., Peer Reviewed, Authored by: Roger Bergua1, WillWiley1, Amy Robertson1, Jason Jonkman1, Cédric Brun2, Jean-Philippe Pineau2, Quan Qian3, Wen Maoshi3, Alec Beardsell4, Joshua Cutler4, Fabio Pierella5, Christian Anker Hansen5, Wei Shi6, Jie Fu6, Lehan Hu6, Prokopios Vlachogiannis7, Christophe Peyrard7, Christopher Simon Wright8, Dallán Friel8, ØyvindWaage Hanssen-Bauer9, Carlos Renan dos Santos9, Eelco Frickel10, Hafizul Islam10, Arjen Koop10, Zhiqiang Hu11, Jihuai Yang11, Tristan Quideau12, Violette Harnois12, Kelsey Shaler13, Stefan Netzband14, Daniel Alarcón15, Pau Trubat15, Aengus Connolly16, Seán B. Leen17, and Oisín Conway17 1National Wind Technology Center, National Renewable Energy Laboratory, Golden, CO 80401, USA 2Research&Development Department, Bureau Veritas – Marine Division, 44818 Saint-Herblain, France 3Research Institute, CSSC Haizhuang Windpower Co. Ltd, Chongqing, 401122, China 4Turbine Engineering, DNV, Bristol, BS2 0PS, UK 5Department of Wind and Energy Systems, Technical University of Denmark, 2800 Lyngby, Denmark 6State Key Laboratory of Coastal and Offshore Engineering, Dalian University of Technology, Dalian, 116024, China 7National Hydraulics and Environment Laboratory (LNHE), EDF R&D, 78400 Chatou, France 8Gavin&Doherty Geosolutions Ltd., Dublin, D14 X627, Ireland 9Institute for Energy Technology, 2007 Kjeller, Norway 10Maritime Research Institute Netherlands (MARIN), 6708 PM Wageningen, the Netherlands 11School of Engineering, Newcastle University, Newcastle upon Tyne, NE1 7RU, UK 12Floating Offshore Group, PRINCIPIA, 13600 La Ciotat, France 13Power and Technology Department, Shell International Exploration and Production, Houston, TX 77079, USA 14Fluid Dynamics and Ship Theory, Hamburg University of Technology, 21073 Hamburg, Germany 15Department of Civil and Environmental Engineering, Universitat Politècnica de Catalunya, 08034 Barcelona, Spain 16Department of Offshore Wind, Wood Group Kenny, Galway, H91 R9YR, Ireland 17Department of Mechanical Engineeri, Postprint (published version)

Postprint (published version)

This paper delves into the application of digital twin monitoring techniques for enhancing offshore floating wind turbine performance, with a detailed case study that uses open-source digital twin software. We explore the practical implementation of digital twins and their efficacy in optimizing operations and predictive maintenance, focusing on controlling the real-time structural state of composite wind turbine structures and forecasting the remaining useful life by tracking the fatigue state in the structure. Our findings emphasize digital twins’ potential as a valuable tool for renewable energy, driving efficiency and sustainability in offshore floating wind installations. These aspects, along with the aforementioned simulations, whether in real-time or forecasted, reduce costly and unnecessary inspections and scheduled maintenance., Objectius de Desenvolupament Sostenible::7 - Energia Assequible i No Contaminant, Objectius de Desenvolupament Sostenible::9 - Indústria, Innovació i Infraestructura, Postprint (published version)

A principios de 2023, el consejo de ministros aprobó los planes de ordenación del espacio marítimo (poem), en la que se recogen un total de 18 zonas aptas para la instalación de parques eólicos. En cataluña, la encontramos en frente del golf de roses, zona en la que está pensada la instalación del parc tramuntana. Sin embargo, el desarrollo de este proyecto tendría una serie de impactos irreversibles tanto en mar como en tierra, lo que hace que mucha gente de la zona se haya opuesto al parque eólico. el objetivo de este trabajo, tal y como su título indica, es el estudio de una solución fotovoltaica flotante alternativa al parque eólico, tratando de minimizar todos estos aspectos negativos y encontrar un equilibrio entre impacto ambiental y generación de energía renovable que sea de más agrado para la gente que vive en el empordà. En primer lugar, se hace un estudio preliminar de la zona y sus condiciones climáticas. Posteriormente, se procede al diseño 3d de toda la plataforma mediante el programa rhinoceros. Luego importamos el modelo al programa compassis, donde se llevan a cabo todas las simulaciones estructurales y de comportamiento en la mar para garantizar el correcto funcionamiento de la plataforma fotovoltaica. Para finalizar, se hace el estudio y diseño de la planta eléctrica y una estimación de la generación de energía que la solución diseñada sería capaz de generar.

Wind energy is currently a crucial player in the global transition toward sustainable and renewable energy sources. With the new geopolitical strategies, the focus on renewable energy intensifies, bringing out the role of wind energy and the investment in offshore wind turbine energy sector in order to secure a diversified and sustainable energy future. This thesis presents a structural optimisation of a semi-submersible floating platform for offshore wind turbines following the novel methodology introduced in the study "Definition of a reference model for structural finite element analysis of an offshore wind turbine floating foundation". Firstly, an overview of wind energy is presented, with a special focus on the evolution of offshore wind energy and the new trends due to the latest plans and agreements. The thesis continues by introducing offshore wind turbines, their components and typology. A background review regarding the important structural, aerodynamics and hydrodynamics is presented followed with the introduction of the reference system considered which is the UMaine VolturnUS-S and the IEA Wind 15-MW offshore reference wind turbine. The system is presented with the explanation of the novel methodology, system description, simulation and optimisation process, which defines an objective function to be iteratively minimized to optimise the surface groups thicknesses of the elements that compose the system to obtain a functional semi-submerges floating platform. After simulating and optimising a first case system, it was found that the optimised system is not functional because of the structural steel mass surpassing the allowable mass for the system floatation. This is due to critical weak points in the structure with high equivalent von Misses stress needing high thicknesses. An implementation of internal reinforcement elements is then studied for a second case study, obtaining a platform with radial stiffeners in the top and the bottom of the main column, Outgoing

Estudio sobre la energía eólica en el mundo, su influencia y la necesidad de su desarrollo para el futuro. Se exploran los temas relacionados con los parques eólicos y las características de los aerogeneradores, las subestaciones, las cimentaciones de las estructuras y la interconexión eléctrica de los sistemas. Se tratan las diferencias entre la eólica terrestre y la marina y se va profundizando en la segunda, mostrando sus ventajas, sus inconvenientes y muchos otros aspectos sobre ella., Exploración de la producción y consumo de las energías no renovables y renovables y una profundización en estos mismos conceptos de la eólica desde el pasado hasta la actualidad, además de algunas estimaciones a futuro. Estudio del recurso natural del viento para comprender sus cualidades y la metodología para aprovecharlas para extraer energía mediante los aerogeneradores de todos los tipos, focalizando cada vez más a medida que se avanza en los casos de grandes potencias y la eólica offshore. Comparación de las múltiples diferencias existentes entre la eólica terrestre y la marina y, posteriormente, tratando en más detalle las diferencias económicas entre ambas. Análisis del funcionamiento de los aerogeneradores y la interconexión eléctrica entre estos, las subestaciones y la red eléctrica. Visualización de la gran variedad de alternativas de cimentaciones para realizar en los parques offshore, siendo uno de los aspectos más destacables de estos en comparación a los parques onshore. Investigación de las características adecuadas y beneficiosas que debe tener una localización marina para la instalación de parques eólicos y de los motivos por los que algunos países han sido más destacados en esto que otros, todo desde el punto de vista global, europeo y español, progresivamente. Comentar sobre las diversas ventajas en muchos sentidos que aporta la inclusión de la energía eólica en el funcionamiento del mundo para las personas, pero también los inconvenientes que llevará consigo, tanto energéticos como sociales y éticos. Exploración de ejemplos reales de parques eólicos marinos de varios estilos y en mares de diversos países para conseguir una visión realista y diversa de las posibilidades que proporciona dicha rama de la eólica, mirando primero fuera de Europa y focalizando en esta después. Investigación de los proyectos de parques eólicos marinos que se encuentran en fase de desarrollo, para ver las posibilidades estimadas a futuro y los países que pretenden que la, Exploration about the production and consumption of the non-renewable and renewable energies and an in-depth look of these same concepts about the wind energy from the past to the present, furthermore some future estimations. Study of the wind to comprehend their qualities and the methodology to be able to take profit of them to obtain energy by means of all types of wind turbines, focusing while it progresses in cases of large power systems and in offshore wind energy. Comparison of the multiple differences between onshore wind energy and offshore wind energy and, afterwards, look at economic differences between them with more detail. Analysis about the operation of wind turbines and their electrical interconnection with substations and the electrical grid. Viewing about one of the more remarkable aspects that onshore wind farms have not as much as offshore wind farms, the large quantities of alternative types of foundations. Investigation about appropriate and beneficial features that a marine location must have to be suitable for a wind farm and the reasons that explain why some countries have been more remarkable than others, all of this from a global, European, and Spanish point of view, progressing gradually. Discuss about the many advantages that means the inclusion of the wind energy in the functioning of the world for the people, but also the disadvantages that bring with it, as much energy as social and ethical. Research about real examples of various styles of offshore wind farms and where they can be located to has a realistic and varied view about all the possibilities that bring these wind energy branch, seeing first outside Europe and after focusing in it. Analysis about the offshore wind farm projects that are in development phase to see the estimations about their possibilities in the future and the countries that pretend to include the wind energy in their electrical grid. Development of a superficial analysis of a particular zone to expound on a d

This thesis presents a method to optimize the power generation of an offshore floating wind farm during its design phase. The basic principle of the presented method is the reduction of the wake effect on the wind farm, which improves the power generated in each turbine, by means of numerical simulations using openfast and fast.Farm. Besides the maximization of the power generation, the space used by the wind farm has also been assessed, in an effort to reduce the area occupied by the turbines. The wind turbine model used is the oc3 hywind, coupled with a nrel 5mw turbine. The models have been verified and several wind farm layouts have been simulated.

This study reports the results of the second round of analyses of the Offshore Code Comparison, Collaboration, Continued, with Correlation and unCertainty (OC6) project Phase III. While the first round investigated rotor aerodynamic loading, here, focus is given to the wake behavior of a floating wind turbine under large motion. Wind tunnel experimental data from the UNsteady Aerodynamics for FLOating Wind (UNAFLOW) project are compared with the results of simulations provided by participants with methods and codes of different levels of fidelity. The effect of platform motion on both the near and the far wake is investigated. More specifically, the behavior of tip vortices in the near wake is evaluated through multiple metrics, such as streamwise position, core radius, convection velocity, and circulation. Additionally, the onset of velocity oscillations in the far wake is analyzed because this can have a negative effect on stability and loading of downstream rotors. Results in the near wake for unsteady cases confirm that simulations and experiments tend to diverge from the expected linearized quasi-steady behavior when the rotor reduced frequency increases over 0.5. Additionally, differences across the simulations become significant, suggesting that further efforts are required to tune the currently available methodologies in order to correctly evaluate the aerodynamic response of a floating wind turbine in unsteady conditions. Regarding the far wake, it is seen that, in some conditions, numerical methods overpredict the impact of platform motion on the velocity fluctuations. Moreover, results suggest that the effect of platform motion on the far wake, differently from original expectations about a faster wake recovery in a floating wind turbine, seems to be limited or even oriented to the generation of a wake less prone to dissipation., Postprint (published version)

Avui en dia, les energies renovables estan jugant un paper molt important en el sector, i la seva demanda creixent fa que aquestes adquireixin un gran potencial per a la seva continua implantació. Restringits pel flux d’aire, la poca disponibilitat d’espai i l’impacte visual, els parcs eòlics terrestres estan arribant al seu límit, de manera que cal buscar una alternativa, els parcs eòlics marins., Hoy en día, las energías renovables desempeñan un papel muy importante en el sector, y su creciente demanda hace que tengan un gran potencial para seguir implantándose. Restringidos por el flujo de aire, la disponibilidad limitada de espacio y el impacto visual, los parques eólicos terrestres están llegando a su límite, por lo que hay que buscar una alternativa, los parques eólicos marinos., Today, renewable energies are playing a very important role in the sector, and their growing demand means that they have great potential for continued implementation. Restricted by air flow, limited space availability and visual impact, land-based wind farms are reaching their limits, so an alternative, offshore wind farms, must be sought.

Embracing renewable energy is pivotal in the journey toward reducing carbon emissions in the power industry, providing a cleaner and more sustainable alternative to traditional fossil fuels. The European Commission has set ambitious energy objectives for the next few years, with a target of achieving a 1236 GW installed capacity of renewable energy by 2030. Offshore wind energy is set to play a substantial role in achieving these objectives, as it is ex- pected to serve as the primary energy source for half of the EU’s energy mix. The necessity for a fully interconnected electrical grid across Europe is spurring the development of emerging technologies. One of these innovative concepts involves the establishment of Offshore Energy Islands (OEIs), where multiple Offshore Wind Farms (OWFs) are linked to an offshore infras- tructure - Hub. This hub then facilitates the transmission of generated electricity to different countries. Different transmission power systems can be employed, being the most common HVAC or HVDC technologies. The major differences between these technologies are in terms of power losses and investment costs. In the context of this master’s thesis, a 1 GW OWF connected to an OEI in the North Sea will provide energy to both Germany and Denmark. The primary objective of this study is to assess the optimal dispatch strategy and transmission configuration that yields the highest annual revenue. Various scenarios have been examined, including the utilization of HVAC lines for both Denmark and Germany, HVDC lines for both Denmark and Germany and a combination of HVAC transmission to Denmark and HVDC transmission to Germany, as well as the reverse configuration. The findings reveal that HVDC transmission systems outperform HVAC in terms of efficiently delivering electricity to the shore, mainly because they do not require reactive power. How- ever, it’s worth noting that HVAC systems, being a more established technology, come with substantially lower initi

The offshore windmills have a lifespan of 20-25 years, owing to that, a significant amount of wind farms will be decommissioned over the next years. The decommissioning of offshore wind farms has still an important lack of knowledge on the decommissioning time and costs. The vessels play a major role in the decommissioning process being used to carry the dismantling operations as well as the transportation. Therefore, in this research a simulation model has been developed to analyse the impact that the vessels characteristics, have on the time and cost following a quantitative model based research methodology. To simulate the weather conditions a Markovian model with weather windows and weather persistence has been implemented. It has been found that the loading capacity has a relevant trade off with the decommissioning time and costs being able to decrease the time in more than a 22%. A sensitivity analysis conducted, has revealed the different wind farm factors that have an influence on the vessel selection, as well as the optimal loading capacity and number of vessels for two different cases

As offshore wind energy expands in Europe, maritime planners increasingly need to consider the potential effects of these activities on the different types of marine protected areas (MPAs), including Natura 2000 sites. The aim of this article is to critically review the initial development of offshore wind energy inside and/or in the vicinity of Mediterranean Natura 2000 sites and other types of MPAs. The western Mediterranean Sea is taken as an example as this is where most of the offshore wind developments have been proposed. In order to open up discussion of offshore wind energy policy and guide ecological research that supports holistic decisions regarding offshore wind farm (OWF) installation in the region, we (i) outline the context of Natura 2000 and other MPA policy in the Mediterranean for OWF development, (ii) summarize the potential impacts of OWF on EU-protected habitats and species, (iii) assess the interactions of OWFs, the Natura 2000 sites, and other MPAs, and (iv) propose recommendations to approach OWF development in the Mediterranean in order to safeguard the Natura 2000 sites and other MPAs. After documenting the potential overlaps between OWFs and MPAs in the western Mediterranean, we recommend OWFs be placed outside Natura 2000 and other MPA sites, including their buffer zones. We also advocate for rigorous and independent Appropriate Assessments to be carried out for OWF proposals that could affect protected areas., The authors thank the three reviewers who have helped us greatly to improve the manuscript with their valuable comments and suggestions. This research was carried out in the frame of the BIOPAIS project (www.oceanshealth.udg.edu/en/biopais.html), which has the support of the Fundación Biodiversidad of the Spanish Ministry for the Ecological Transition and the Demographic Challenge (MITECO) within the framework of the Recovery, Transformation, and Resilience Plan (PRTR), financed by the European Union—NextGenerationEU., Peer Reviewed, Postprint (published version)

El treball (TFG) se centra en el procés d’implementació d’un Product Lifecycle Management (PLM), el programari 3DExperience, en una empresa dedicada al món de l'eòlica offshore, EOLOS Floating Lidar Solutions, una startup creada el 2014 que ha experimentat un creixement accelerat, a la qual em vaig incorporar com a estudiant en pràctiques l’octubre del 2022. La implantació del software, una feina en la qual he participat des que vaig arribar a la companyia, pretén optimitzar l'eficiència i la productivitat dels recursos dedicats a la gestió dels projectes orientats a la captació i subministrament de dades a la indústria de l’energia eòlica marina a través d’una boia LIDAR flotant autònoma, i, al mateix temps, enfortir la comunicació interna de l'empresa. Els primers apartats del TFG inclouen, a banda de les motivacions personals que m’han empès a dur-lo a terme, un capítol dedicat a contextualitzar-lo en el sector de l’eòlica offshore. Intento també aportar una descripció detallada de l’empresa i del servei que comercialitza, així com de l’estat previ en què es trobava la documentació, aspectes imprescindibles a l’hora d’optar per la implantació d’un PLM. Més endavant em focalitzo en explicar què és i com funciona el PLM i els avantatges que aporta en comparació amb altres sistemes de gestió de la informació, abans de descriure les etapes del projecte en el qual he estat involucrat per aconseguir una adaptació òptima al programari i el potencial que aquest té en el futur de la companyia. Finalment, es presenten els progressos i resultats obtinguts fins ara en aspectes com l’eficiència de la gestió dels projectes, l’enfortiment en la integració dels diferents departaments de l'empresa i la reducció dels temps i costos de producció., El trabajo (TFG) se centra en el proceso de implementación de un Product Lifecycle Management (PLM), el software 3DExperience, en una empresa dedicada al mundo de la eólica offshore, EOLOS Floating Lidar Solutions, una startup creada el 2014 que ha experimentado un crecimiento acelerado, a la que me incorporé como estudiante en prácticas en octubre del 2022. La implantación del software, una tarea en la que he participado desde que llegué a la compañía, pretende optimizar la eficiencia y la productividad de los recursos dedicados a la gestión de los proyectos orientados a la captación y suministro de datos para la industria de la energía eólica marina y, al mismo tiempo, fortalecer la comunicación interna de la empresa. Los primeros apartados del TFG incluyen, además de las motivaciones personales que me han empujado a llevarlo a cabo, un capítulo dedicado a su contextualización en el sector de la eólica offshore. Intento también aportar una descripción detallada de la empresa y del servicio que comercializa, así como del estado previo en el que se encontraba la documentación, aspectos imprescindibles a la hora de optar por la implantación de un PLM. Más adelante me focalizo en explicar qué es y como funciona el PLM y las ventajas que aporta en comparación con otros sistemas de gestión de la información, antes de describir las etapas del proyecto en el que me he involucrado para conseguir una adaptación óptima al software y el potencial que este programa informático tiene en el futuro de la compañía. Finalmente, se presentan los progresos y resultados obtenidos hasta ahora en aspectos como la eficiencia en la gestión de los proyectos, el fortalecimiento de la integración de los diferentes departamentos de la empresa y la reducción de los tiempos y costes de producción., The project (TFG) focuses on the implementation process of a Product Lifecycle Management (PLM), the 3DExperience software, in a company dedicated to the world of offshore wind, EOLOS Floating Lidar Solutions, a startup created in 2014 that has experienced accelerated growth, which I joined as an intern in October 2022. The implementation of the software, a task in which I have been involved since I arrived at the company, aims to optimise the efficiency and productivity of the resources dedicated to the management of projects aimed at capturing and supplying data for the offshore wind energy industry and, at the same time, strengthen the company's internal communication. The first sections of the TFG include, in addition to the personal motivations that have pushed me to carry it out, a chapter dedicated to its contextualisation in the offshore wind sector. I also try to provide a detailed description of the company and the service it sells, as well as the previous state of the documentation, essential aspects when opting for the implementation of a PLM. I then focus on explaining what PLM is and how it works and the advantages it offers compared to other information management systems, before describing the stages of the project in which I have been involved to achieve an optimal adaptation to the software and the potential that this software has for the company's future. Finally, I present the progress and results obtained so far in aspects such as efficiency in project management, the strengthening of the integration of the different departments of the company and the reduction of production times and costs.

Global power capacity is increasingly being comprised by renewable energy sources, where wind farms stand out as paramount power stations. Therefore, the structural health of wind turbines (WTs) represents an essential factor in the energy industry. Specifically, offshore jacket-type WT supports are under critical operational and environmental conditions. Hence, a damage detection strategy is stated, considering several types of structural states and limitations in the quantity of acquired data. The proposed methodology consists of a PCA-based data transformation, in which initially known healthy data are used to be compared with a set of data to be diagnosed; then the damage or healthy states are predicted based on the Mahalanobis distance and threshold value. Because it is a semi-supervised technique, there is no requirement to have damage data on hand to construct the model. The strategy is tested in a scaled-down WT experimental tower., Peer Reviewed, Objectius de Desenvolupament Sostenible::7 - Energia Assequible i No Contaminant, Postprint (published version)

Early detection of damage in the support structure (submerged part) of an offshore wind turbine is crucial as it can help to prevent emergency shutdowns and extend the lifespan of the turbine. To this end, a promising proof-of-concept is stated, based on a transformer network, for the detection and localization of damage at the jacket-type support of an offshore wind turbine. To the best of the authors’ knowledge, this is the first time transformer-based models have been used for offshore wind turbine structural health monitoring. The proposed strategy employs a transformer-based framework for learning multivariate time series representation. The framework is based on the transformer architecture, which is a neural network architecture that has been shown to be highly effective for natural language processing tasks. A down-scaled laboratory model of an offshore wind turbine that simulates the different regions of operation of the wind turbine is employed to develop and validate the proposed methodology. The vibration signals collected from 8 accelerometers are used to analyze the dynamic behavior of the structure. The results obtained show a significant improvement compared to other approaches previously proposed in the literature. In particular, the stated methodology achieves an accuracy of 99.96% with an average training time of only 6.13¿minutes due to the high parallelizability of the transformer network. In fact, as it is computationally highly efficient, it has the potential to be a useful tool for implementation in real-time monitoring systems., Peer Reviewed, Objectius de Desenvolupament Sostenible::7 - Energia Assequible i No Contaminant, Postprint (published version)

Este proyecto tiene como principal objetivo diseñar un parque eólico marino con la capacidad de producir 500 mw de potencia eléctrica. Para ello se habrá de escoger un emplazamiento que cumpla con ciertos requisitos. Posteriormente, se dimensionará una plataforma eólica en función de las condiciones meteorológicas del emplazamiento. Seguidamente, se dimensionará el parque eólico para que cumpla con los objetivos preestablecidos incluyendo. Por último, se hará un cálculo de la rentabilidad que puede ofrecer este proyecto.

Aquest projecte parteix de la inquietud i de la voluntat d'augmentar la quantitat d'energia d'origen renovable que es produeix a Catalunya, explorant nous espais i formes de produir-la, encara no aplicats al territori català. L'objectiu que persegueix és redactar l'avantprojecte d'un parc eòlic marí a la costa catalana i demostrar que aquesta tecnologia, a l'igual que al nord d'Europa, és viable. A part de redactar el projecte tècnic, també se'n fa una anàlisi ambiental bàsica i s'analitza l'impacte que aquest parc eòlic tindria sobre el mercat elèctric. L'estudi valora les zones que són aptes per a instal·lar la tecnologia eòlica marina i vetlla perquè la presència del parc no alteri significadament les condicions ambientals de la zona ni les activitats que actualment es realitzen en l’espai establert. Es determina que a Catalunya es disposa de poques zones que reuneixin aquestes condicions i s'ubica en parc eòlic en una de les zones aptes més àmplia, la costa del Baix Empordà. Posteriorment, l'estudi se centra en aprofitar l'àrea disponible per a obtenir la quantitat més gran d'energia possible tractant, a la vegada, de reduir l'impacte que la construcció d'un parc eòlic pot comportar. Partint d’aquesta premissa, se seleccionen els aerogeneradors que ofereixen un millor aprofitament de l'espai i els sistemes de fixació que generen menys impacte sobre el llit marí. De l'estudi se n'extreu la viabilitat, tant tècnica com econòmica, de construir un parc d'energia eòlica al Mediterrani, projectant un parc de 1,17 GW de potència capaç de generar anualment 5.949 GWh. Aquest estudi també mostra que la convivència del parc amb la resta d'activitats marines és possible i ressalta la reducció del preu de l'energia elèctrica pels consumidors que el parc podria generar tenint en compte l’actual sistema marginalista d’electricitat., Este proyecto parte de la inquietud y voluntad de aumentar la cantidad de energía de origen renovable que se produce en Catalunya, explorando nuevos espacios y formas de producirla, aún no aplicados en el territorio catalán. El objetivo que persigue es redactar el anteproyecto de un parque eólico marino en la costa catalana y demostrar que esta tecnología, al igual que en el resto de Europa, es viable. Aparte de redactar el proyecto técnico, también se realiza un análisis ambiental básico y se analiza el impacto que este parque eólico tendría sobre el mercado eléctrico. El estudio valora las zonas que son aptas para la instalación de la tecnología eólica marina y se cuida de que la presencia del parque no altere significativamente las condiciones ambientales de la zona ni las actividades que actualmente se realizan en el espacio establecido. Se determina que en Catalunya se dispone de pocas zonas que reúnan estas condiciones y se ubica el parque en una de las zonas aptas más amplia, la costa del Baix Empordà. Posteriormente, el estudio se centra en aprovechar el área disponible para obtener la mayor cantidad de energía posible, tratando a la vez, de reducir el impacto que la construcción de un parque eólico puede ocasionar. Partiendo de esta premisa, se seleccionan los aerogeneradores que ofrecen un mejor aprovechamiento del espacio y los sistemas de fijación que generan menos impacto sobre el lecho marino. Del estudio se extrae la viabilidad, tanto técnica como económica, de construir un parque de energía eólica en el Mediterráneo, proyectando un parque de 1,17 GW de potencia capaz de generar anualmente 5.949 GWh. Este estudio también demuestra que la convivencia del parque con el resto de las actividades marinas es posible y resalta la reducción del precio de la energía eléctrica para los consumidores que el parque podría generar teniendo en cuenta el actual sistema marginalista de electricidad., This project stems from the concern and the aim to increase the amount of renewable energy produced in Catalonia, exploring new spaces and ways of producing it, which have not yet been applied there. The purpose is to draw up the preliminary project for an offshore wind farm off the Catalan coast and demonstrate that this technology, as in the rest of Europe, is feasible in Catalonia. In addition to drawing up the technical project, a basic environmental analysis, as well as an analysis of the impact that this wind farm would have on the electricity market, are carried out. The study assesses the areas that are suitable for the installation of offshore wind technology and ensures that the presence of the wind farm does not significantly alter the environmental conditions of the area or the activities that are currently carried out in the established space. It is determined that there are few areas in Catalonia that meet these conditions and the park is located in one of the largest suitable areas, the Baix Empordà coast. Subsequently, the study focuses on taking advantage of the available area to obtain as much energy as possible, while trying to reduce the impact that the construction of a wind farm can cause. Based on this premise, the wind turbines that offer the best use of space and the fastening systems that generate the least impact on the seabed are selected. The study shows the technical and economic feasibility of building a wind farm in the Mediterranean, projecting a 1.17 GW wind farm capable of generating 5,949 GWh annually. This study also demonstrates that the coexistence of the wind farm with other marine activities is possible and highlights the reduction in the price of electricity for consumers that the wind farm could generate, taking into account the current marginalist electricity system.

This thesis addresses the need for policy and regulatory frameworks to support the sustainable growth of the offshore wind industry in new and emerging markets. The global need for clean and renewable energy is driving the emergence of offshore wind energy as a viable solution to achieve net-zero emissions goals. The offshore wind market has experienced significant growth, with a current installed capacity of 54.9 GW in 19 countries. However, new and emerging markets face challenges in establishing suitable policy and regulatory frameworks to support OW development. Policy targets and instruments play a crucial role in converting OW potential into electricity generation. This study identifies a research gap in literature for policy and regulatory frameworks for new and emerging markets, and thus, the research proposes a comprehensive set of policy and regulation options derived from the findings. The research methodology includes a systematic literature review, case studies of well-established offshore wind markets (United Kingdom, Germany, and Denmark), and experts’ interviews from government agencies and industry players, ensuring a robust and holistic approach to meet the research objectives. Findings for policy options emphasize the importance of clear targets and vision, stable support mechanisms, indirect industry support, and other policy tools. New and emerging markets should establish ambitious offshore wind targets with specific timelines and develop a long-term vision and strategy with a predicatble pipeline of projects. Direct support mechanisms, tailored to market conditions, provide certainty for investors. Indirect support mechanisms, such as local content requirements and investment in research and development, foster industry growth. Regulatory considerations highlight that transparent and streamlined procedures for leasing and licensing, along with simplified and integrated processes, are crucial. Inclusiveness through public consultation and impro

Diseño de una embarcación tipo supply con propulsión eléctrica para tareas de apoyo al parque eólico tramuntana

Aquest treball es realitza amb l’objectiu d’assolir un escenari viable en la col·locació de turbines en un parc eòlic marí flotant a Gran Canària (layout), emprant un algorisme d’optimització matemàtic i posteriorment comparant el resultat amb un altre. Per fer-ho s’ha utilitzat l’algorisme genètic i s’ha emprat com a eina de programació el Matlab. Finalment la col·locació de les turbines utilitzant l’algorisme genètic ha resultat en un valor del LCOE de 69,38 €/MWh. Comparant-lo amb el cas base que es tracta d’una col·locació tradicional de turbines, el qual resulta amb un valor del LCOE de 74,38 €/MWh, l’algorisme proposat presenta una millora del 6,31 % respecte a aquest. Per altra banda, comparant el resultat obtingut amb l’algorisme implementat per l’IREC, en concret l’algorisme PSO, amb un valor del LCOE de 68,89€/MWh, es pot dir que l’algorisme PSO és un 0,65 % millor que l’algorisme genètic a l’hora d’optimitzar l’escenari d’estudi. També s’ha comprovat la viabilitat econòmica de la instal·lació, sent aquesta viable, ja que té un període de retorn de 9 anys. Per a pròxims estudis seria interessant realitzar un algorisme híbrid entre l’algorisme genètic i l’algorisme PSO per comprovar si milloren els resultats., Este trabajo se realiza con el objetivo de alcanzar un escenario viable en la colocación de turbinas en un parque eólico marino flotante en Gran Canaria (layout), empleando un algoritmo de optimización matemático y posteriormente comparando el resultado con el otro. Para ello se ha utilizado el algoritmo genético y se ha cogido como herramienta de programación Matlab. Finalmente, la colocación de las turbinas utilizando el algoritmo genético ha resultado en un valor del LCOE de 69,38 €/MWh. Comparándolo con el caso base, que se trata de una colocación tradicional de turbinas, que resulta con un valor del LCOE de 74,38 €/MWh, el algoritmo propuesto presenta una mejora del 6,31 % respecto al mismo. Por otro lado, comparando el resultado obtenido con el algoritmo implementado por IREC, en concreto el algoritmo PSO, con un valor del LCOE de 68,89 €/MWh, puede decirse que el algoritmo PSO es un 0,65 % mejor que el algoritmo genético a la hora de optimizar el escenario de estudio. También se ha comprobado la viabilidad económica de la instalación, siendo ésta viable ya que tiene un periodo de retorno de 9 años. Para próximos estudios sería interesante realizar un algoritmo híbrido entre el algoritmo genético y el algoritmo PSO para comprobar si mejoran los resultados., This work is carried out with the aim of achieving a viable scenario for the placement of turbines in a floating offshore wind farm in Gran Canaria (layout), using a mathematical optimization algorithm and then comparing the result with another. Genetic algorithm has been used to do this, and Matlab has been used as a programming tool. Finally, the placement of the turbines using the genetic algorithm has resulted in an LCOE value of € 69,38 / MWh. Comparing it with the base case which is a traditional turbine placement, which results in an LCOE value of € 74.38 / MWh, the proposed algorithm shows an improvement of 6,31 % over this one. On the other hand, comparing the result obtained with the algorithm implemented by IREC, specifically the PSO algorithm, with an LCOE value of 68.89 € / MWh, it can be said that the PSO algorithm is 0,65 % better than the genetic algorithm when it comes to optimizing the study scenario. Also the economic viability of the installation has been verified, being feasible as it has a return period of 9 years. For future studies, it would be interesting to perform a hybrid algorithm between the genetic algorithm and the PSO algorithm to see if the results improve., Objectius de Desenvolupament Sostenible::7 - Energia Assequible i No Contaminant

During the last decades, wind turbine technology development has been phenomenal in the renewable field, as we are witnessing the construction of enormous wind turbines in the middle of oceans. The blades of wind turbines are an engineering marvel consisting of complex curved geometry surfaces. Optimising the blade shape can significantly improve the energy output. This project focused on the study of the operating logic of wind turbines, and in particular, their blades’ design. XFOIL was used to study the aerodynamic behaviour of the NACA four-digit airfoils family. This study allowed to characterise the aerodynamic properties of each airfoil, which were then validated by direct comparison with Computational Fluid Dynamics simulations’ results and third- party experimental work. Then, an algorithm based on the Blade Element Momentum methodology was programmed, to configure and predict the performance of a certain blade design through and iterative process. Optimisation methods were applied to find a set of profiles, chord and attack and twist angles distribution, to compose a blade design that optimises the aerodynamic performance of the blade, thus maximising the harvestable energy from the wind. The optimisation resulted in a blade design that has increased the power obtained by 67% with respect to the non-optimised base case., Objectius de Desenvolupament Sostenible::7 - Energia Assequible i No Contaminant::7.b - Per a 2030, ampliar la infraestructura i millorar la tecnologia per tal d’oferir serveis d’energia moderns i sos­tenibles per a tots els països en desenvolupament, en particular els països menys avançats, els petits estats insulars en desenvolupament i els països en desenvolupament sense litoral, d’acord amb els programes de suport respectius

© 2023 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting /republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works, This paper proposes a new strategy for optimal grid frequency regulation (FR) in an interconnected power system where regional ac grids and an offshore wind farm are linked via a multi-terminal high voltage direct-current (MTDC) network. In the proposed strategy, decentralized H8 controllers are developed to coordinate the operations of synchronous generators and MTDC converters, thus achieving optimal power sharing of interconnected ac grids and minimizing frequency deviations in each grid. To develop the controllers, robust optimization problems are formulated and solved using a dynamic model of the hybrid MTDC-linked grids with model parameter uncertainty and decentralized control inputs and outputs. The model orders of the controllers are then reduced using a balanced truncation algorithm to eliminate unobservable and uncontrollable state variables while preserving their dominant response characteristics. Sensitivity and eigenvalue analyses are conducted focusing on the effects of grid measurements, parameter uncertainty levels, and communication time delays. Comparative case studies are also carried out to verify that the proposed strategy improves the effectiveness, stability, and robustness of real-time FR in MTDC-linked grids under various conditions., This research was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (corresponding author: Y. Kim)., Postprint (author's final draft)

The integration of offshore wind to the grid comprises multiple areas and systems, the main ones being the wind farms themselves, the point of connection and the transmission system. Each of this areas are undergoing important transformations in the last few years: larger wind turbines enabling larger wind farms, the emergence of HVDC transmission systems and the higher prevalence of weaker connection points. In addition, new technologies such as PtX and BESS are emerging in its synergies with offshore wind are still to be proved and implemented. This MSc Thesis aims to bring all these elements together by means of a holistic assessment tool. The tool has been designed in a modular approach to give maximum flexibility to the user: it can assess the integration of different wind farm to different point of connection by using different transmission systems. The tool assesses steady state voltage stability limits for weak grids and use this as an input for an economical optimization of BESS and PtX systems. The main outputs of the tool once used are the maximum power that can be injected to the point of connection before voltage violation and the optimal size of the PtX or BESS that can support the system when the power limit was to be reached. The assessment tool is applied to a specific reference offshore wind farm with two study cases: one designed for an HVAC transmission and a second one for an HVDC transmission. The results are analysed and compared. The flexibility of the tool and its ability to obtain results in a programmatic and straight forward approach allows to perform sensitivity analyses for key parameters allowing to get insights about how transmission length, short circuit level or X/R ratio affects the strength of grid in the point of connection. The effect of costs and energy prices are also assessed in regards of the optimal sizing of PtX and BESS and it is found that energy price assumptions have a big impact in the result. Also, it is found that e, Outgoing, Objectius de Desenvolupament Sostenible::7 - Energia Assequible i No Contaminant

The output power in wind farms is highly related to the behaviour and interaction of the turbine wakes in them. The fact of modeling the wakes in wind farms the most accurate possible way by using a simple analytical wake model (AWM) is of a great relevance. Recently, it has been raised the question whether AWMs can be calibrated according to the local conditions in the wind farm, in an attempt to reduce their predictive uncertainty. To this regard, one parameter of the AWMs that has been shown highly sensitive to the flow conditions is the wake growth rate, with a proven positive, linear relationship with respect to the turbulence intensity. In this line, the first goal of this project is to calibrate different AWMs for an offshore, operational wind farm, in order to increase their accuracy when estimating the wind farm power output. The second goal of this project is to asses twp types of wakes superposition models on different analytical wake modes. To accomplish them first is designed an available framework for the assessment of analytical wake models using the operational off-shore wind farm dataset., Outgoing

Offshore wind energy is increasingly being realized at deeper ocean depths where jacket foundations are now the greatest choice for dealing with the hostile environment. The structural stability of these undersea constructions is critical. This paper states a methodology to detect and classify damage in a jacket-type support structure for offshore wind turbines. Because of the existence of unknown external disturbances (wind and waves), standard structural health monitoring technologies, such as guided waves, cannot be used directly in this application. Therefore, using vibration-response-only accelerometer measurements, a methodology based on two in-cascade Siamese convolutional neural networks is proposed. The first Siamese network detects the damage (discerns whether the structure is healthy or damaged). Then, in case damage is detected, a second Siamese network determines the damage diagnosis (classifies the type of damage). The main results and claims of the proposed methodology are the following ones: (i) It is solely dependent on accelerometer sensor output vibration data, (ii) it detects damage and classifies the type of damage, (iii) it operates in all wind turbine regions of operation, (iv) it requires less data to train since it is built on Siamese convolutional neural networks, which can learn from very little data compared to standard machine/deep learning algorithms, (v) it is validated in a scaled-down experimental laboratory setup, and (vi) its feasibility is demonstrated as all computed metrics (accuracy, precision, recall, and F1 score) for the obtained results remain above 96%., Peer Reviewed, Objectius de Desenvolupament Sostenible::7 - Energia Assequible i No Contaminant::7.2 - Per a 2030, augmentar substancialment el percentatge d’energia renovable en el con­junt de fonts d’energia, Objectius de Desenvolupament Sostenible::7 - Energia Assequible i No Contaminant, Postprint (published version)

The development of offshore renewable energy structures is growing at a fast pace, and their maintenance will become critical in further years. Because steel corrosion on offshore structures is one of their highest maintenance cost, researchers are working to replace steel by Fibre Reinforced Polymers (FRP), due to their immunity to corrosion. This is done in the EU H2020 funded project FIBREGY, which also seeks improving maintenance costs by incorporating Structural Health Monitoring (SHM) strategies. A critical issue in SHM is the damage detection process, which is addressed in this paper. This study aims to characterize the dynamic behaviour of an offshore windmill FRP tower, and its evolution due the presence of structural damage. This analysis will be carried out using a Finite Element Model (FEM) of the structure, and the Serial-Parallel mixing theory to characterize the material performance. A sensitivity analysis of the changes in the dynamic response of the tower (frequencies and modal shapes) produced by structural damage is carried out. This analysis will provide the optimum design variables and objective functions required by a damage detection algorithm. The algorithm is optimization based, since it converts the damage detection problem into a mathematical one, and finds the best design variables to minimize the objective function. The algorithm is also model based, as it uses the structural model to obtain the objective function for the proposed design variables. Finally, this work presents the analysis of a potential damage scenario, in order to evaluate if the damage is effectively detected., Postprint (published version)

The operation of offshore wind power plants with respect to power quality and grid code compliance must be verified for different conditions in the design phase using harmonic analysis methods. This paper addresses this verification by first considering a scenario in which wind turbines operate with a typically used modulation strategy, carrier-based pulse width modulation. The studies are performed at several operating points, not only at the rated condition, and at two points of the electrical infrastructure, at the point of connection of the wind turbine and at the point of common coupling of the offshore wind farm. For this type of modulation technique and according to the resonance conditions of the studied offshore system, the harmonic distortion of current signals is relatively high and the compliance of the German – grid code is not achieved. To tackle this, wind turbine manufacturer oriented solutions are proposed with the aim of improving the harmonic emission of the offshore wind farm. The implementation of a particular solution of selective harmonic elimination is presented together with complementary solutions to further improve the harmonic emission of the wind power facility. Furthermore, this paper discloses the modeling approach to account for an adequate harmonic assessment of the wind power plant under study.

L'objectiu es fer un estudi dels diferents sistemes de transmissió elèctrica entre parcs eòlics offshore i les subestaciones de terra a on arriba la potencia. Després d'una introducció de les característiques especials de les turbines i parcs marítims, les dues diferents possibilitats de transmissió seràn discutides: transmissió en alterna i les seves limitacions i transmissió en continua i les seves variants., El objetivo es hacer un estudio de los diferentes sistemas de transmisión eléctrica entre parques eólicos offshore i las subestaciones de tierra donde llega la potencia. Después de una introducción de las características especiales de las turbinas i parques marítimos, las dos diferentes posibilidades de transmisión serán discutidas: transmisión en alterna y sus limitaciones y transmisión en continua y sus variantes., This Project is a study about energy transmission systems for the o shore wind environment. Chapter 1 is an introduction to wind energy and wind turbine technology. It starts with a brief history of wind exploitation and explains the current state of wind energy among the rest of the electricity generating energies. Then it moves to present the types of turbine and their classi cation, with detailed remark on the standard turbine and its forming elements such as the generator. Lastly, it ends with a presentation of the control levels carried out to control a wind farm. On the next chapter, Chapter 2, the structure of a wind farm is explained, covering issues such as the collection of power at the output of the turbines and the technical characteristics of the o shore substations. Moreover, the di erent methods of installing turbines on sea are discussed. To continue, on Chapter 3 a study about High-Voltage Alternating Current transmission is done. First of all, a presentation on this method of transmission is done, and then the di erent technologies that it comprises are also covered (AC cables, power electronics for AC systems such as power reactive compensators, interconnection between turbine and cable, etc). Finally, the limitations of HVAC transmission are exposed. Chapter 4 does a study on the HVAC counterpart: High-Voltage Direct Current transmission, following the same scheme as in Chapter 3. First, the main characteristics of this type of transmission are stated, followed by some DC transmission solutions and an explanation on DC cables. Then, the much needed converter technology for a DC system is studied, with all its variations that can nd an o shore application. Finally the two main DC transmission systems (line-commutated basedconverter and voltage source based-converter transmissions) are presented and compared together with the HVAC transmission. On Chapter 5 we nd the conclusions, and highlights the main deductions carried out on the project. Also

El presente proyecto se centra en el cálculo y la simulación del diseño de una estructura tipo trípode de un aerogenerador marino ubicado en el archipiélago de las islas canarias. el proyecto se ha dividido en dos partes. En primer lugar, se estudian las cargas estructurales (de carácter ambiental, la mayoría) que afectan al modelo diseñado. en un segundo caso se introducen los valores en un programa de análisis y se analiza su comportamiento también se realizará un estudio del emplazamiento de la estructura y un plan de prevención de riesgos. Los cálculos y modelos realizados en los estudios previos han sido tratados con herramientas informáticas de cálculo que, combinadas entre sí, permitan la obtención de resultados lo más óptimos posibles, y justifiquen su funcionamiento ante las condiciones ambientales en las que se plantea que dicha estructura marina sea operativa.

The purpose of this document is to describe the procedure carried out for the design of the Windcrete mooring system anchoring to the floating platform. The scope of this design is limited to site B of COREWIND project (Canary Islands) and includes ULS, SLS and FLS analysis. The design is based on the DNVGL standards, particularly DNVGL-ST-0119 which incorporates specific requirements for floating wind platforms. Additionally, requirements from Eurocodes EN-1992: Design of concrete structures and EN-1993: Design of steel structures were considered for the design in accordance with recommendations from DNVGL-ST-0126 . The focus of the task is kept on the design of the steel anchor plate to which the fairlead is welded, the anchor of this element to the concrete platform, as well as the load transfer to the platform. This is a critical point of the structure given the fact that mooring lines may impose concentrated loads of considerable magnitude, which could eventually compromise watertightness and floatability of the platform, and thus the integrity of the structure. This task was carried out with the aim to ensure an adequate behavior of the anchor plate under design conditions in order to maintain the global integrity of the platform. The fairlead itself is out of the scope of the task., Preprint

This paper provides a summary of the work done within the OC6 Phase II project, which was focused on the implementation and verification of an advanced soil–structure interaction model for offshore wind system design and analysis. The soil–structure interaction model comes from the REDWIN project and uses an elastoplastic, macroelement model with kinematic hardening, which captures the stiffness and damping characteristics of offshore wind foundations more accurately than more traditional and simplified soil–structure interaction modeling approaches. Participants in the OC6 project integrated this macroelement capability to coupled aero-hydro-servo-elastic offshore wind turbine modeling tools and verified the implementation by comparing simulation results across the modeling tools for an example monopile design. The simulation results were also compared to more traditional soil–structure interaction modeling approaches like apparent fixity, coupled springs, and distributed springs models. The macroelement approach resulted in smaller overall loading in the system due to both shifts in the system frequencies and increased energy dissipation. No validation work was performed, but the macroelement approach has shown increased accuracy within the REDWIN project, resulting in decreased uncertainty in the design. For the monopile design investigated here, that implies a less conservative and thus more cost-effective offshore wind design., Article signat per 29 autors/es: Roger Bergua, Amy Robertson, Jason Jonkman, Andy Platt, Ana Page, Jacob Qvist, Ervin Amet, Zhisong Cai, Huali Han, Alec Beardsell, Wei Shi, Josean Galván, Josean Galván Department of Wind Energy, eureka!, Errigoiti, Spain Search for more papers by this author Erin Bachynski-Polić, Gill McKinnon, Violette Harnois, Paul Bonnet, Loup Suja-Thauvin, Anders Melchior Hansen, Iñigo Mendikoa Alonso, Ander Aristondo, Tommaso Battistella, Raúl Guanche, Paul Schünemann, Thanh-Dam Pham, Pau Trubat, Daniel Alarcón, Florence Haudin, Minh Quan Nguyen, Akhilesh Goveas, Postprint (author's final draft)

This paper presents an adapted particle swarm optimization model for the electrical layout planning of floating offshore wind farms (FOWFs). A comprehensive model is considered by taking into account the entire wind turbine connection possibilities as well as stochastic wind speed and wind direction and the computation of the wake effect within the wind farm. Furthermore, dynamic power cables used for the connection of floating offshore wind turbines are considered as well as their respective acquisition and installation costs. The reliability assessment of the electrical components and the influence on the energy generation are also taken into account. The developed optimization model is validated in this paper at first against a reference model developed by Banzo et al. Then the model is applied on a 500 MW FOWF case. The optimized collection grid results in a decrease of 4.5% of the total costs and a reduction of the energy losses by 6.4% compared to the existing layout of the FOWF. Finally, the use of either solely dynamic power cables or a combination of static and dynamic cables is studied. The findings show that for this particular case the use of solely dynamic power cables is favorable due to the avoidance of cost-intensive submarine joints and additional installation activities., Peer Reviewed, Postprint (published version)

El viento es una manifestación indirecta de la energía que nos envía el sol, por tanto, aparece como resultado del diferente grado de calentamiento de la superficie de la tierra por los rayos solares, así como por el movimiento de rotación del planeta sobre sí mismo. Actualmente hay más de 341.000 aerogeneradores instalados en todo el planeta, con un total aproximado de 743gw de capacidad. hoy en día estos aerogeneradores están contribuyendo a evitar más de 1.1 billones de toneladas de co^2 en todo el mundo, lo que equivale a las emisiones anuales de carbono de sudamérica. El presente proyecto tiene como objetivo la realización de una propuesta de un plan de mantenimiento del parque eólico del golfo de león el cual aún está en fase de construcción y se prevé la instalación en 2022. primeramente, el trabajo se centra en una parte teórica donde hay la parte explicativa de las energías renovables, los tipos de mantenimiento y normativa aplicada en francia. seguido de una parte más práctica donde se ha hecho un estudio de los tipos de fallos que se suelen encontrar, los recursos necesarios para hacer el mantenimiento y un programa de actividades específicas a realizar durante las operaciones de mantenimiento.

n este trabajo se realiza un estudio de viabilidad de un parque eólico marino en las costas de la Bretaña francesa. Para empezar, se hace un estudio del recurso eólico de tres períodos diferentes mediante datos tomados por boyas marinas. Los objetivos son calcular los factores de escala y forma de Weibull por varios métodos y mediante unas pruebas de evaluación de la bondad de ajuste escoger el más adecuado a la vez que comprobar cómo varían estos dependiendo del tamaño de la muestra. A continuación, se calcula la densidad de energía con el método que presenta mejor ajuste. En el análisis técnico se analizan los sistemas más importantes que conforman un parque eólico marino flotante. Se describen cada uno de ellos y se escoge el más adecuado en base a los resultados obtenidos en las fuentes consultadas y su idoneidad para la zona de implantación elegida. Por último, se realiza una estimación del coste total del proyecto teniendo en cuenta los costes materiales, de instalación, operación, mantenimiento, desmantelamiento y gestión de proyectos

Low frequency AC technology has been presented as a configuration that can potentially reduce the total cost of existing transmission systems. Such cost reduction could be achieved by increasing the power transfer capacity of High Voltage AC cables operating at low frequency and removing the offshore converter when compared to High Voltage DC systems. The purpose of this paper is to suggest an optimal design of Low Frequency AC transmission systems. This results in obtaining the optimal Low Frequency AC voltage level, location, number of reactors and the Back-to-Back converter size for an Offshore Wind Power Plants with a defined rated power and distance to shore. Additionally, the Low Frequency AC, High Voltage AC and High Voltage DC equivalent configurations are compared in terms of total cost and the final transmission system is selected. The analysis of a practical case study is presented in detail, followed by an expansion of the methodology application on various configurations. Also, cost sensitivity analyses for two opposed cases are provided to identify the variation of the break-even distance of Low Frequency AC with High Voltage AC and High Voltage DC. Lastly, different non-standard transmission frequencies are analyzed and an optimal frequency is defined for a range of Offshore Wind Power Plants rated powers and distances. The paper presents a methodology that can be applied considering different relevant parameters, e.g. transmission voltages, cable cross sections and cost data. Based on parameters available in the literature, the study results show that Low Frequency AC is not currently viable., Peer Reviewed, Postprint (published version)

Estudi operacional de la plataforma eòlica flotant windcrete. Aquest concepte, planteja una torre i plataforma integral en una sola peça de formigó pretesat. Al llarg del treball, s'estudia la viabilitat de l'àlternativa de transport i instal·lació per via humida, sense fer ús de grans vaixells grua., Objectius de Desenvolupament Sostenible::7 - Energia Assequible i No Contaminant

Structural health monitoring for offshore wind turbine foundations is paramount to the further development of offshore fixed wind farms. At present time there are a limited number of foundation designs, the jacket type being the preferred one in large water depths. In this work, a jacket-type foundation damage diagnosis strategy is stated. Normally, most or all the available data are of regular operation, thus methods that focus on the data leading to failures end up using only a small subset of the available data. Furthermore, when there is no historical precedent of a type of fault, those methods cannot be used. In addition, offshore wind turbines work under a wide variety of environmental conditions and regions of operation involving unknown input excitation given by the wind and waves. Taking into account the aforementioned difficulties, the stated strategy in this work is based on an autoencoder neural network model and its contribution is two-fold: (i) the proposed strategy is based only on healthy data, and (ii) it works under different operating and environmental conditions based only on the output vibration data gathered by accelerometer sensors. The proposed strategy has been tested through experimental laboratory tests on a scaled model., Peer Reviewed, Postprint (published version)

The design distance of offshore wind power plants connected through HVAC transmission systems might be extended due to the introduction of mid-cable reactors for reactive power compensation purposes and the latest developments of AC cables for higher voltages. Therefore, the applicability limits between HVAC and HVDC systems must be revised. This paper analyzes the contribution that mid-cable reactive power compensation has on increasing the distance limits of HVAC transmission systems. A methodology is developed to determine an optimal design of such transmission systems. In this methodology, cost of power losses and reactors are minimized for multiple wind speed conditions. As a result, the optimal HVAC voltage level and the optimal number of reactors and their location are determined for different OWPP rated powers and distances. Also, the final transmission system is selected between HVAC and HVDC equivalent configurations based on total costs., Peer Reviewed, Postprint (published version)

Floating offshore wind is an emerging technology with the potential of harvesting wind resources in deeper waters, where current fixed offshore technology is limited. In order to tap into the vast potential in the oceans, floating wind needs to become cost competitive. The objective of this thesis is to estimate the cost and economic metrics for a specific floating platform concept developed by X1 Wind, by incorporating cost uncertainties. The study applies a Monte Carlo approach to simulate joint probability distributions of cost and economic metrics (NPV, IRR and LCOE). The results of the study indicate that X1 Wind’s platform design offers a competitive LCOE on the short-medium term, compare to results from studies and expectations from the industry and experts. By implementing uncertainty into cost estimations, the report addresses the potential benefits and limitations of using probability distributions as inputs for Monte Carlo simulation.

This work deals with structural health monitoring for jacket-type foundations of offshore wind turbines. In particular, a vibration-response-only methodology is proposed based on accelerometer data and deep convolutional neural networks. The main contribution of this article is twofold: (i) a signal-to-image conversion of the accelerometer data into gray scale multichannel images with as many channels as the number of sensors in the condition monitoring system, and (ii) a data augmentation strategy to diminish the test set error of the deep convolutional neural network used to classify the images. The performance of the proposed method is analyzed using real measurements from a steel jacket-type offshore wind turbine laboratory experiment undergoing different damage scenarios. The results, with a classification accuracy over 99%, demonstrate that the stated methodology is promising to be utilized for damage detection and identification in jacket-type support structures., Peer Reviewed, Postprint (author's final draft)

Despite its influence on wind energy service life, condition-based maintenance is still challenging to perform. For offshore wind farms, which are placed in harsh and remote environments, damage detection is critically important to schedule maintenance tasks and reduce operation and maintenance costs. One critical component to be monitored on a wind turbine is the pitch bearing, which can operate at low speed and high loads. Classical methods and features for general purpose bearings cannot be applied effectively to wind turbine pitch bearings owing to their specific operating conditions (high loads and non-constant very low speed with changing direction). Thus, damage detection of wind turbine pitch bearings is currently a challenge. In this study, entropy indicators are proposed as an alternative to classical bearing analysis. For this purpose, spectral and permutation entropy are combined to analyze a raw vibration signal from a low-speed bearing in several scenarios. The results indicate that entropy values change according to different types of damage on bearings, and the sensitivity of the entropy types differs among them. The study offers some important insights into the use of entropy indicators for feature extraction and it lays the foundation for future bearing prognosis methods., Postprint (published version)