Yes / The offshore wind energy is increasingly becoming an attractive source of energy due to having lower environmental impact. Effective operation and maintenance that ensures the maximum availability of the energy generation process using offshore facilities and minimal production cost are two key factors to improve the competitiveness of this energy source over other traditional sources of energy. Condition monitoring systems are widely used for health management of offshore wind farms to have improved operation and maintenance. Reliability of the wind farms are increasingly being evaluated to aid in the maintenance process and thereby to improve the availability of the farms. However, much of the reliability analysis is performed offline based on statistical data. In this article, we propose a drone-assisted monitoring based method for online reliability evaluation of wind turbines. A blade system of a wind turbine is used as an illustrative example to demonstrate the proposed approach. / SURE Grant scheme. SESAME H2020 Project under Grant 101017258.

The Coastal Virginia Offshore Wind (CVOW) pilot project will be only the second operating offshore wind project in the United States when it enters service later this year. This gives Virginia, a state criticized for a weak regulatory environment and environmental policy that has been slow to embrace renewable energy, an opportunity to take a leadership position in the development of this zero-carbon resource. One explanation for the CVOW project's emergence is the Diffusion of Innovation Theory (DIT), which relates the rate of adoption of novel solutions to factors such as relative advantage, compatibility, complexity, trialability and observability – all factors which play, to varying degrees, in favor of this project. Another explanation involves an inversion of Regulatory Capture Theory (RCT). RCT posits that regulated industries capture otherwise neutral regulating bodies, to the detriment of the generic public interest. Others argue that RCT underplays the degree to which regulators prioritize the interests of the regulated community over the public interest, defending a Climate of Capitulation Theory (CCT). While Virginia has recently taken an aggressively pro-wind policy position as it competes with other states to serve as a hub for the offshore wind industry and responds to voter interests in sustainability, the CVOW project problematizes RCT. It also suggests that a real-world climate of capitulation may not always work against the public interest. Judiciously combined with DIT, CCT can explain how external pressures on Virginia government, combined with internal pressures exerted by public opinion in relation to the development of the offshore wind industry, are steering 'capitulation' in directions that assist the public interest in sustainability. In the real world of energy politics, and against RCT, regulators are and have never been neutral, and therefore liable to capture. In a climate of capitulation, and setting aside other questions of the public interest, the willingness of regulators to serve the interests of the regulated community can, when taking external and internal factors into account, redound to the public interest in sustainability. / Master of Arts / Virginia has historically been criticized for a weak regulatory environment and for having environmental policies that have been slow to embrace renewable energy. Yet, the state is about to become home to just the second offshore wind project in America and plans are moving forward on a proposal to build the largest offshore wind project in North America off the Commonwealth's coast by 2026. This thesis explores the factors that led to the development of the Coastal Virginia Offshore Wind (CVOW) pilot project and how Virginia became a major player in this zero-emission clean energy resource. One explanation is provided by the Diffusion of Innovation Theory (DIT) which details how innovative solutions take hold and examines factors which can accelerate adoption rates. Another explanation is found by considering an inversion of Regulatory Capture Theory (RCT). RCT is premised on the idea that regulated industries can hold sway over the regulating bodies, often to the detriment of the generic public interest. A variation of RCT focused on Virginia environmental policy, Climate of Capitulation Theory (CCT), explains how Virginia regulators have, at times, not provided strong enough environmental protections. However, the CVOW project shows how the regulated community, policy makers and public opinion are coming together to position Virginia at the forefront of the offshore wind industry and how the willingness of regulators to serve the interests of the regulated community can serve the interests of both the public and the environment, as well.

In the present study, a numerical simulation tool has been developed for the rotor-floater-tether coupled dynamic analysis of Multiple Unit Floating Offshore Wind Turbine (MUFOWT) in the time domain including aero-blade-tower dynamics and control, mooring dynamics and platform motion. In particular, the numerical tool developed in this study is based on the single turbine analysis tool FAST, which was developed by National Renewable Energy Laboratory (NREL). For linear or nonlinear hydrodynamics of floating platform and generalized-coordinate-based FEM mooring line dynamics, CHARM3D program, hull-riser-mooring coupled dynamics program developed by Prof. M.H. Kim’s research group during the past two decades, is incorporated. So, the entire dynamic behavior of floating offshore wind turbine can be obtained by coupled FAST-CHARM3D in the time domain. During the coupling procedure, FAST calculates all the dynamics and control of tower and wind turbine including the platform itself, and CHARM3D feeds all the relevant forces on the platform into FAST. Then FAST computes the whole dynamics of wind turbine using the forces from CHARM3D and return the updated displacements and velocities of the platform to CHARM3D. To analyze the dynamics of MUFOWT, the coupled FAST-CHARM3D is expanded more and re-designed. The global matrix that includes one floating platform and a number of turbines is built at each time step of the simulation, and solved to obtain the entire degrees of freedom of the system. The developed MUFOWT analysis tool is able to compute any type of floating platform with various kinds of horizontal axis wind turbines (HAWT). Individual control of each turbine is also available and the different structural properties of tower and blades can be applied. The coupled dynamic analysis for the three-turbine MUFOWT and five-turbine MUFOWT are carried out and the performances of each turbine and floating platform in normal operational condition are assessed. To investigate the coupling effect between platform and each turbine, one turbine failure event is simulated and checked. The analysis shows that some of the mal-function of one turbine in MUFOWT may induce significant changes in the performance of other turbines or floating platform. The present approach can directly be applied to the development of the remote structural health monitoring system of MUFOWT in detecting partial turbine failure by measuring tower or platform responses in the future.

This Thesis aims to explore how the opening of offshore wind power development blocks in Norway results in conflicts between fishermen and the offshore wind industry. The goal is to identify synergies between the two maritime sectors which may be used in future consultation phases. The Thesis includes qualitative research that was compiled by document analysis and triangulated by examining and interpreting data found within the literature review, hearing responses, interviews, and public letters. The results unveil that conflict inducing factors in Norway are similar to international cases. These factors include concerns for noise under construction and operation, the loss of acreage/livelihood, the lack of knowledge, and the disregard for fishermen’s concerns.  It was found that offshore wind could lead to more sustainable fishing practices and give way to aquaculture activity. Wind farms may serve as a safe haven for juvenile marine species and increase biodiversity by the creation of artificial reefs on foundation structures. An in-situ demonstration of these effects was suggested to increase knowledge and facilitate coexistence. A willingness from both parties to come to a solution was identified and it was suggested to employ an objective mediator in future consultations/negotiations. Finally, it was suggested to deploy offshore wind farther from land, and to offset the cost of increased depth by increasing the capacity of projects.

With the rapid expansion of offshore wind power capacity in the world in the last decade, innovative offshore solutions are designed in order to meet the upcoming power capacity installations. As in all other energy sectors, offshore wind power has certain conditions that have to be met to increase the efficacy of the outcome.In this thesis, wake effect impact on the production results of Hexicon AB’s innovative floating and rotating offshore wind power platform project with 3 turbines located in the southern part of Sweden are analyzed through the application of “Analytical wake models” and the “Actuator Disc method”, with the help of WindSim.The results of Analytical models and Actuator Disc method were found to be independent of one another. Even though analytical wake models did not find any wake effect impact among the turbines, the results can be considered as logical. However, the Actuator Disc method created unexpected results which might stem from the WindSim – AD combination. It is therefore recommended to further explore these scenarios with other (more) advanced simulation tools.

Sweden has a great potential for offshore wind energy production. As technology develops and policies change, construction of offshore wind farms in the country is likely to increase. The presented methodology is to apply MCDM and AHP methods in a GIS to produce an evaluation map of potential sites for offshore wind energy production.  The aim of this thesis was to determine what data is relevant and needed to translate Swedish and international standards and regulations regarding offshore wind farm siting into one or more layers of GIS data within the exclusive economic zone of Sweden. Furthermore the locations of the existing Areas of National Interests for offshore wind energy production have been evaluated using the evaluation map. The evaluation map has been obtained using several exclusionary criteria and buffer distances as well as four evaluation criteria. In addition, the results of this study have been used to calculate a potential net annual energy production for offshore wind energy in Sweden. The analysis considers some of the social, technical and environmental constraints present in offshore wind farm siting. The exclusion, buffer and evaluation criteria were determined in the initial literature review of previous studies on the topic. Datasets were collected from several different open online resources and Swedish government agencies, the analysis was performed using the QGIS software. To assess the results, the resulting evaluation map has been classified into four different categories: poor, average, good and excellent. The analysis shows that it is possible to translate Swedish and international standards into one layer of GIS data. Furthermore the results of this study show that 52% of the defined Areas of National Interest for offshore wind energy production should not be considered for wind farm siting according to the exclusion constraints, additionally only 19% of the Areas of National Interest for offshore wind energy production are classified as good or excellent. In contrast, 20.3% of the entire study area is deemed to be suitable for offshore wind farm siting, out of which 62.7% is classified as good or excellent. The potential net annual energy production has been estimated to be 56.1 TWh annually within the Areas of National Interest for offshore wind energy production and 915.3 TWh annually within the entire study area. / Sverige har en stor potential för produktion av havsbaserad vindkraft. När teknologin utvecklas och de politiska förutsättningar förändras, kommer konstruktionen av havsbaserad vindkraft i landet troligtvis öka. Den presenterade metodologin går ut på att använda MCDM och AHP metoder i ett GIS för att producera en utvärderingskarta för potentiella platser att producera havsbaserad vindenergi.  Målet med den här studien har varit att ta reda på vilken data som krävs och är relevant för att överföra svensk samt internationell standard och regler kring placeringen av havsbaserad vindkraft till ett eller flera lager av GIS data inom Sveriges exklusiva ekonomiska zon. Vidare har de existerande riksintressena för havsbaserad vindkraft utvärderats med hjälp av utvärderingskartan. Denna karta har blivit framtagen med hjälp av flertalet buffertzoner samt exkluderings- och fyra stycken utvärderingskriterier. Slutligen har studiens resultat används för att beräkna en potentiell årlig energiproduktion för offshore vindkraft i Sverige. Studien beaktar några av de sociala, tekniska och miljömässiga begränsningar som finns för havsbaserad vindenergi. Buffertzonerna samt exkluderings- och utvärderingskriterierna har bestämts med hjälp av en inledande litteraturstudie av tidigare forskning på ämnet. Den datan som använts i analysen har inhämtats från flera olika öppna onlineresurser samt från svenska myndigheter. Den efterföljande analysen har genomförts med hjälp av programmet QGIS. För att möjliggöra en kvantifiering av resultaten har utvärderings kartan omklassificerats till fyra olika kategorier: “poor”, “average”, “good” samt “excellent”. Studien visar att det är möjligt att överföra svensk samt internationell standard och regler till ett lager av GIS data. Resultatet visar att att enbart 48% av arean inom de definierade riksintressena för havsbaserad vindkraft bör beaktas vid allokering av havsbaserad vindenergi, enligt de begränsningar som definierats i denna studie. Vidare påvisar resultatet att enbart 19% av arean inom de utpekade riksintressena för vindkraft kan klassificeras som “good” eller “excellent”. Samtidigt påvisar studien att 20.3% av studieområdet bedöms som lämpligt för allokering av havsbaserad vindkraft, av dessa lämpliga områden klassificeras 62.7% som “good” och “excellent”. Den potentiella årliga energiproduktionen uppskattas till 56.1 TWh inom riksintressena för havsbaserad vindkraft samt till 915.3 TWh inom hela studieområdet.

The UK has an abundant offshore wind resource with offshore wind farming set to grow rapidly over the coming years. Optimisation of energy production is of the utmost importance and accurate estimates of wind speed distributions are critical for the planning process. Synthetic aperture radar (SAR) data can provide synoptic, wide area wind field estimates at resolutions of a few kilometres and has great potential for wind resource assessment. This thesis addresses the key challenges for the operational implementation of SAR in this context; namely the accuracy of SAR wind retrievals and the ability of SAR to characterise the mean wind speed and wind power density. We consider the main stages of SAR wind retrieval; the retrieval algorithm; sources of a priori information; the optimal configuration of the retrieval system; and the challenges for and accuracy of SAR wind resource estimation. This study was conducted for the eastern Irish Sea in the UK, a region undergoing significant offshore wind energy development. A new wind retrieval algorithm was developed that implements a maximum a posterior probability (MAP) method drawn from Bayesian statistics. MAP was demonstrated to be less sensitive to input errors than the standard direction-based wind speed algorithm (DWSA) and provides a simple retrieval quality check via the error reduction ratio. Retrieval accuracy is strongly influenced by the quality of a priori information. The accuracy of two operationally viable a priori sources, mesoscale numerical weather prediction (NWP) data and WISAR image directions, was evaluated by comparison against in-situ wind observations and WERA coastal data. Results show that NWP wind speeds produce good wind speed and direction estimates with standard deviations of ¬±2 ms-1 and ±16o respectively. WISAR directions were less accurate producing standard deviations ranging from ±20o to ±29o, but were preferable when strong differences between NWP timesteps were observed. The accuracy of SAR wind retrievals was evaluated by comparison against in-situ wind observations. The MAP algorithm was found to provide modest improvements in retrieval accuracy over DWSA. Highest quality retrievals achieved using the CMOD5 forward model, producing wind speeds with a RMSE of 1.83 ms-1. Regarding the ability of SAR to estimate offshore wind resources, dataset density was found to be a controlling parameter. With 103 scenes available mean wind speeds were well characterised by comparison against in-situ observations and Wind Atlas results, while wind power density showed considerable errors. The accuracy of wind speed maps was further improved by accounting for wind direction and fetch effects upon the SAR wind distribution. A key strength of the SAR wind fields is their ability to identify the effect of mesoscale structures upon the surface wind field with atmospheric gravity waves observed in 30% of the images. These structures are shown to introduce wind speed fluctuations of up to ±2 ms-1 at scales of 5 to 10 km and may have significant implications for wind power prediction. These findings show that SAR may provide an important source of wide area wind speed observations as a complement to existing wind resource estimation techniques. SAR may be of particular use in coastal areas where complex wind fields are observed.

Offshore wind power is attracting increasing levels of research and investment. The use of HVDC transmission and the development of DC grids are topics with similar high levels of interest that go hand in hand with the development of large scale, far from shore wind farms. Despite increased capital cost of some components, DC power transmission can have significant advantages over AC transmission, in particular in the offshore environment. These advantages are well established for large scale, long distance point to point transmission. This thesis assesses the suitability of a multi-terminal DC power collection network, with short cables and relatively small amounts of power, addresses a number of the technical challenges in realising such a network and shows methods for overall system cost reduction. Technical and modelling challenges result from the interaction between power electronic DC-DC converters and the cables in a DC transmission network. In particular, the propagation of the ripple current in bipole DC transmission cables constructed with a metallic sheath and armour is examined in detail. The finite element method is used to predict the response of the cable to the ripple current produced by the converters. These results are used along with wave propagation theory to demonstrate that cable design plays a crucial role in the behaviour of the DC system. The frequency dependent cable models are then integrated with time domain DC-DC converter models. The work in the thesis is, broadly, in two parts. First, it is demonstrated that care and accuracy are required in modelling the cables in the DC transmission system and appropriate models are implemented and validated. Second, these models are combined with DC-DC converter models and used to demonstrate the practicality of the DC grid, make design recommendations and assess its suitability when compared with alternative approaches (e.g. AC collection and/or transmission).

The offshore wind potential of the Caribbean Sea has barely been exploited. Currently, the offshore wind power industry in Latin America and the Caribbean region is still at very early stages, leaving aside an important resource that otherwise could contribute to satisfy the growing energy demand of the zone. In this study the possibilities arising from a massive exploitation of the wind resource in the Caribbean Sea are assessed. The objective is to investigate if the resources contained in it would be sufficient to satisfy the energy demand of Latin America and the Caribbean, which is foreseen to be about 1900 TWh/year by 2020. To address this question, the “Infinite wind farm” concept is used as a simple way to model the meteorological behaviour and the wind speed in the area. The model is utilized in combination with the bathymetric data of the Caribbean Sea and with a simple economic analysis, to evaluate what the requirements to satisfy the energy demand would be in terms of area, number of turbines, and levelized cost of energy (LCoE). The assessment is performed utilizing different turbine sizes, and inter-turbine separations to find the combination that minimizes the LCoE. It is found that the energy demand of Latin America and the Caribbean could be satisfied using only 125000 km2 (4.5% of the total Caribbean Sea area) of waters shallower than 25m at a cost of 69 €/MWh, if the turbines were separated 6.5D from one another and if they had a rotor diameter of 250m. In that case, 47760 turbines should be installed using only conventional monopile foundations.

A energia eólica é uma das fontes de energia renovável mais promissoras e que cresce mais rapidamente em todo o mundo. O uso da energia eólica pode contribuir para reduzir as emissões de gases de efeito estufa derivados da queima de combustíveis fósseis. Estima-se que o Brasil dispõe de um significativo potencial eólico offshore na sua Zona Econômica Exclusiva de cerca de 1,78 TW. Entretanto, um dos fatores limitantes para o desenvolvimento da energia eólica offshore no Brasil é a inexistência de um marco regulatório. O marco regulatório é uma condição essencial para atrair investimentos no setor e permitir o desenvolvimento do potencial latente. Este estudo tem como objetivo analisar princípios e experiências regulatórias brasileiras e internacionais para subsidiar o debate na formulação de instrumentos normativos com vista a inserção da energia eólica offshore no Brasil. O estudo apresenta um panorama do estado da arte e das tendências tecnológicas para geração de energia eólica offshore que ajuda a compreender como a construção e operação de usinas pode provocar impactos socioambientais e conflitos no espaço oceânico. Uma síntese do conceito de potencial eólico é elaborada, e as rendas econômicas do recurso eólico offshore são analisadas ressaltando-se a necessidade de atuação do Estado na arbitragem de sua extração e distribuição. Por meio da investigação do arcabouço jurídico-regulatório brasileiro, e com uso da metodologia descritiva, constatou-se que não há instrumentos capazes de dar suporte ao desenvolvimento de parques eólicos offshore no Brasil. A partir da análise de princípios e experiências regulatórias brasileiras em geração de energia eólica onshore, geração de energia hidrelétrica, exploração e produção de petróleo e gás natural, e, em geração de energia eólica offshore do Reino Unido, Alemanha, Dinamarca, Holanda, Bélgica, China e Estados Unidos, foram elaborados quadros de referências para servirem de base para o caso do Brasil. Em conclusão, princípios dos modelos brasileiros para outorga de usinas hidrelétricas; princípios do modelo de exploração e produção de petróleo e gás natural, assim como das experiências internacionais em energia eólica offshore aderentes ao ambiente institucional do Brasil, podem ser adotados na formulação de instrumentos jurídicos e normativos com vista a inserção da energia eólica offshore no país. / Wind power is one of the most promising and fastest growing renewable energy sources in the world. The use of wind power can contribute to reduce greenhouse gas emissions from burning fossil fuels. It is estimated that Brazil has a significant offshore wind potential in its Exclusive Economic Zone of about 1.78 TW. However, one of the limiting factors for the development of offshore wind power in Brazil is the lack of a regulatory framework. The regulatory framework is an essential condition to attract investments in the sector and allowing the development of latent potential. This study aims to analyze Brazilian and international regulatory principles and experiences to support the debate in the formulation of normative instruments for the insertion of offshore wind energy in Brazil. The study presents an overview of the state of the art and technological trends for offshore wind power generation that helps to understand how the construction and operation of power plants can cause socio-environmental impacts and conflicts in the ocean space. A synthesis of the concept of wind potential is elaborated, and the economic rents of the offshore wind resource are analyzed emphasizing the necessity of State action in the arbitration of its extraction and distribution. Based on the investigation of the Brazilian legal-regulatory framework and by using the descriptive methodology it was verified that there are no instruments capable of supporting the development of offshore wind farms in Brazil. Based on the analysis of Brazilian principles and regulatory experiences in onshore wind power generation, hydroelectric power generation, oil and natural gas exploration and production, and in offshore wind power generation in the United Kingdom, Germany, Denmark, the Netherlands, Belgium, China, and United States, frameworks of the conceptual references were developed to serve as a basis for the case of Brazil. In conclusion, principles of the Brazilian model for the grant of hydroelectric plants; principles of the Brazilian model for oil, and natural gas exploration and production, as well as of the international offshore wind experiences adhering to the institutional environment of Brazil, can be adopted in the formulation of legal and normative instruments aiming the insertion of offshore wind power in the country.