Renewable energy sources are in strong demand as the need for clean energy is increasing, driven by the need to reach the environmental targets. Offshore wind power is becoming an attractive source as the technology matures and cost decreases. With time all wind farms age and when the time comes one needs to consider end of life alternatives. The objective with this Thesis is to assess lifetime extension of offshore wind farms, with a focus on reliability, availability and maintenance. As of today there are few offshore wind farms reaching their end of life but one needs to be prepared. From the literature review it is clear that there is somewhat limited documentation around lifetime extensions. The reason for lifetime extension is to increase the return on investment (ROI) of the original project, with a limited additional investment. With capital expenditure (CAPEX) being a large part of the overall project cost it is beneficial to achieve more operational years to divide the cost over, one also need to consider increased operations and maintenance (O&M) cost with aging assets. In this Thesis, a Reliability block diagram (RBD) model was developed in ReliaSoft BlockSim to calculate wind turbine failures, their associated downtime and O&M costs to create an overview of the future behaviour and cost. To assess the wind farm economics a financial model was built, based on output from the RBD model, to evaluate the levelized cost of energy (LCOE) and internal rate of return (IRR) for several cases of lifetime extension. A case study was done for a generic wind farm of 30 wind turbines, assumed to be built around 2010 using 3.6MW rated turbines, to illustrate a relevant case. Focus was on O&M cost, and it was assumed the structural integrity of the wind turbines would be maintained for the lifetime extension for up to 10 years.

Wind power is the fastest growing sector of electricity generation in the world and the development of offshore wind resources is an increasingly important component of this growth. While more than 1.5GW have been installed in Europe and China, no turbines have been installed in United States waters even though several have been planned. Offshore wind power development in the United States must contend with significant challenges. There are numerous technical considerations including geological issues and undefined environmental conditions that affect the determination of appropriate design loads. Technological advancements are needed, and logistical questions must be addressed. The regulatory structure can be confusing and most permitting frameworks are not well established. Offshore wind projects are capital intensive and concerns exist that the industry will not be able to achieve a suitable economy of scale. Additionally, concerns about offshore wind impacts cross many areas such as the environment, visual and cultural concerns, navigational issues, and competing uses. This research project examines the technical issues of American offshore wind power and models basic project costs to provide an estimate of the total net present value for hypothetical utility-scale offshore wind projects in the United States. Costs have been examined by building a cost model and employing traditional cash flow analysis, regression, design of experiments, and random sampling techniques. / text

Made available in DSpace on 2014-12-17T13:53:37Z (GMT). No. of bitstreams: 1 JoaoPCM_DISSERT.pdf: 2393754 bytes, checksum: f95d47c17e14c0db5625ca5a0ae4656d (MD5) Previous issue date: 2014-01-21 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / Offshore wind power emits low amounts of gases, is renewable and has better performance than onshore due to its greater stability and higher wind power density, less visual and noise impact, among others. Brazil has a high capacity of generation, but has not yet developed any offshore projects. High costs are a strong impediment. This study is an effort towards pricing offshore resources through Livelized Cost of Energy - LCOE, which represents the minimum return to cover the costs of development, production and maintenance of a wind project. Initially LCOE was calculated for all Brazilian onshore wind farms listed at Bloomberg New Energy Finance R?, accounting for 71 farms. Then hypothetical offshore wind farms were created from the onshore farms, tripling the cost of generation, which is consistent with the literature, and estimating the offshore energy for two locations off the Brazilian coast using satellite data extracted from National Oceanic and Atmospheric Administration. The results demonstrate that offshore resources have the potential to significantly reduce the energy price due to the better performance of the wind at sea / A fonte de energia e?lica offshore emite baixas quantidades de gases causadores do efeito estufa, ? renov?vel e apresenta melhor desempenho do que a fonte onshore em quesitos como maior estabilidade e densidade de pot?ncia dos ventos, menor impacto visual e sonoro, dentre outros. O Brasil possui uma capacidade de gera??o offshore substancialmente elevada, mas ainda n?o desenvolveu nenhum projeto nessa modalidade. Os custos elevados s?o um forte empecilho. Esse estudo ? um esfor?o em dire??o ? explora??o desse campo, precificando a fonte offshore atrav?s do Livelized Cost of Energy LCOE, que representa o retorno m?nimo para cobrir os custos de desenvolvimento, produ??o e manuten??o de um projeto e?lico. O LCOE foi primeiramente calculado para todos os parques e?licos onshore brasileiros listados no Bloomberg New Energy Finance R?, contabilizando 71 parques. Em seguida foram criados parques e?licos offshore hipot?ticos a partir dos parques onshore, triplicando os custos de gera??o, o que est? em conformidade com a literatura especializada, e estimando-se a energia offshore para dois pontos da costa brasileira atrav?s de dados de sat?lite extra?dos do National Oceanic and Atmospheric Administration. Os resultados demonstram que a fonte offshore tem o potencial de reduzir significativamente o pre?o da energia devido ? melhor performance do vento no mar

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.

This paper sets out to analyze the observed wake effect at Block Island Wind Farm. A comparison is made between several wake simulation methods and the observed data at Block Island using analytic and CFD (Computational Fluid Dynamics) modelling methods.  The observed wake results at Block Island show a similar trend evident in earlier papers- a large power deficit found between the first two Wind Turbine Generators (WTGs) in the row followed by a slight variation in power along the row for the remainder of the WTGs. A noticeable difference is seen between the last two WTGs in the row where an increase in power is found. This increase in power is thought to be due to the alignment of the wind farm. Nevertheless, when the observed data is compared with the modeled results, the observed data seem to underestimate the wake effect due to misalignment issue with the nacelle wind direction measurement. A sensitivity analysis is conducted on the Wake Decay Constant (WDC) and Turbulence Intensity (TI) values. The results show a maximum power variation of ≈30% between a WDC value of 0.07 and 0.04 and ≈18% for TI values between 8% and 14%. The findings show that a value in the higher range of the examined WDC (0.06 and 0.07) and TI (12% and 14%) values represent a better comparison to the observed data. Nevertheless, it is not recommended to alter these parameters to fit the observed data. Furthermore, due to high uncertainty in the data measurements, and hence observed results, a clear conclusion indicating which wake model best represents the wake effect at Block Island cannot be stated.

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.

Made available in DSpace on 2014-12-17T13:53:39Z (GMT). No. of bitstreams: 1 LanaVLCS_DISSERT.pdf: 716391 bytes, checksum: b33e1111ab67ab2b0d5834afe0fe5855 (MD5) Previous issue date: 2014-06-27 / Universidade Federal do Rio Grande do Norte / The consumption of energy on the planet is currently based on fossil fuels. They are responsible for adverse effects on the environment. Renewables propose solutions for this scenario, but must face issues related to the capacity of the power supply. Wind energy offshore emerging as a promising alternative. The speed and stability are greater winds over oceans, but the variability of these may cause inconvenience to the generation of electric power fluctuations. To reduce this, a combination of wind farms geographically distributed was proposed. The greater the distance between them, the lower the correlation between the wind velocity, increasing the likelihood that together achieve more stable power system with less fluctuations in power generation. The efficient use of production capacity of the wind park however, depends on their distribution in marine environments. The objective of this research was to analyze the optimal allocation of wind farms offshore on the east coast of the U.S. by Modern Portfolio Theory. The Modern Portfolio Theory was used so that the process of building portfolios of wind energy offshore contemplate the particularity of intermittency of wind, through calculations of return and risk of the production of wind farms. The research was conducted with 25.934 observations of energy produced by wind farms 11 hypothetical offshore, from the installation of 01 simulated ocean turbine with a capacity of 5 MW. The data show hourly time resolution and covers the period between January 1, 1998 until December 31, 2002. Through the Matlab R software, six were calculated minimum variance portfolios, each for a period of time distinct. Given the inequality of the variability of wind over time, set up four strategies rebalancing to evaluate the performance of the related portfolios, which enabled us to identify the most beneficial to the stability of the wind energy production offshore. The results showed that the production of wind energy for 1998, 1999, 2000 and 2001 should be considered by the portfolio weights calculated for the same periods, respectively. Energy data for 2002 should use the weights derived from the portfolio calculated in the previous time period. Finally, the production of wind energy in the period 1998-2002 should also be weighted by 1/11. It follows therefore that the portfolios found failed to show reduced levels of variability when compared to the individual production of wind farms hypothetical offshore / O consumo de energia no planeta ? atualmente baseado no uso de combust?veis f?sseis. Eles s?o respons?veis por efeitos negativos sobre o meio-ambiente. As energias renov?veis prop?em solu??es para esse cen?rio, mas devem encarar quest?es relacionadas ? capacidade de fornecimento de energia. A energia e?lica offshore desponta como uma alternativa promissora. A velocidade e estabilidade dos ventos s?o maiores sobre oceanos, mas a variabilidade dos mesmos pode provocar flutua??es inconvenientes ? gera??o de energia el?trica. Para diminuir isso, uma combina??o de parques e?licos distribu?dos geograficamente foi proposta. Quanto maior a dist?ncia entre eles, menor a correla??o entre a velocidade dos ventos, aumentando a probabilidade de que produzam conjuntamente um sistema de energia mais est?vel, com menos flutua??es da produ??o de energia. O uso eficiente da capacidade de produ??o dos parques e?licos, entretanto, depende da distribui??o deles em ambientes mar?timos. O objetivo desta pesquisa foi analisar a aloca??o ?tima de parques e?licos offshore na costa leste dos EUA, atrav?s da Moderna Teoria de Carteiras. A Moderna Teoria de Carteiras foi empregada de modo que o processo de constru??o das carteiras de energia e?lica offshore contemplasse a particularidade da intermit?ncia dos ventos, atrav?s dos c?lculos de retorno e risco da produ??o dos parques e?licos. A pesquisa foi desenvolvida com 25.934 observa??es de energia, produzidas por 11 parques e?licos offshore hipot?ticos, a partir da instala??o simulada de 01 turbina oce?nica com capacidade m?xima de 5 MW. Os dados apresentam resolu??o de tempo hor?ria e cobrem o per?odo entre 01 de janeiro de 1998 at? 31 de dezembro de 2002. Por meio do software Matlab R , foram calculadas seis carteiras de m?nima vari?ncia, cada qual para um per?odo de tempo distinto. Diante da desigualdade da variabilidade dos ventos no tempo, estabeleceu-se quatro estrat?gias de rebalanceamento para avaliar o desempenho das carteiras calculadas, o que possibilitou identificar a mais ben?fica ? estabilidade da produ??o de energia e?lica offshore. Os resultados apontaram que a produ??o de energia e?lica dos anos de 1998, 1999, 2000 e 2001 deve ser ponderada pelos pesos das carteiras calculadas nos mesmos per?odos, respectivamente. Os dados de energia de 2002 devem utilizar os pesos oriundos da carteira calculada no per?odo de tempo anterior. Por fim, a produ??o de energia e?lica do per?odo entre 1998-2002 deve ser igualmente ponderada por 1/11. Conclui-se assim que as carteiras encontradas conseguiram demonstrar n?veis de variabilidade reduzidos quando comparados aos da produ??o individual dos parques e?licos offshore hipot?ticos

The aim with this study is to analyze and try to understand the arguments and conflicts associated with the planning and development of offshore wind power in Sweden, and to study various media articles and their significance for offshore wind power in Sweden. A qualitative method has been applied in the form of a media analysis. The material for the study is based on diverse types of articles from the media in the form of news articles, commentaries, and debate articles. The articles I have chosen to analyze come mostly from the most popular news editors in Sweden; "Aftonbladet", "Dagens Nyheter" and "Svenska Dagbladet". There are also news articles from local newspapers so that even smaller local events can be captured and studied. Further in this study, media such as Swedish Radio and SVT Nyheter have been applied where shorter news items can be examined. This result shows how the opposition and arguments for and against offshore wind power are played out in the media and that the media can function as an information provider for offshore wind power linked to the planning and expansion of offshore wind power in Sweden. Many opinions want to highlight the negative consequences of offshore wind power, mainly from a local point of view. In some cases, opposition is also about preserving nature's values and not making interventions in nature that affect biodiversity, but this is something that "NIMBY" may have led to. That media coverage of the topic is largely based on informing people about ongoing projects and preparing press releases with important information about the projects, as well as acting as an information channel.

Wind power is a renewable energy source that is making great strides in the global energy sector. While wind power is a renewable energy source, it is not entirely free from carbon emissions. This is because the production of wind turbines is dependent on the use of energy, and as a result can emit large amounts of carbon dioxide. This is because the production of wind turbines is dependent on the use of energy and as a result can emit large amounts of carbon dioxide. The emissions come from two sources, the materials used in the wind turbine and the energy used in the manufacturing process. Because wind turbine production is global, the geographical location also affects the climate impact. The purpose of this study is therefore to evaluate the climate impact from material and energy use for the different turbine components. Furthermore, it aims to evaluate the total climate impact between on-and offshore wind power as well as evaluate the climate impact between production in Sweden, Germany and China. The climate impact is based on 13 Vestas LCA reports, together with a model developed in excel. The results show that the location of production plays a significant role in the total emissions, due to the large variation in the electricity mix between different countries. Generally, the steel components are the largest contributors to the total CO2 emissions. Consequently, offshore wind has a higher climate impact than its onshore counterpart because the offshore foundation is made of steel. The result is, however, limited due to the lack of standardisation and since specific information regarding wind power is hard to acquire. / Vindkraft är en förnyelsebar energikälla, som gör stora framsteg inom den globala energisektorn. Samtidigt som vindkraften är förnyelsebar, är den inte helt fri från koldioxidutsläpp. Detta beror på att produktionen av vindkraftverk kräver energi och kan därför släppa ut stora mängder koldioxid. Utsläppen kommer från två källor, de material som används i vindkraftverket och energin som behövs vid tillverkningen. Eftersom produktion av vindkraftverk sker på ett globalt plan, har även den geografiska platsen där tillverkningen sker en påverkan på klimatpåverkan. Syftet med denna studie är att undersöka klimatpåverkan från material och energianvändningen fördelat över vindkraftverks huvudkomponenter. Utöver detta, syftar den även till att undersöka den totala klimatpåverkan mellan land- och havsbaserad vindkraft samt hur klimatpåverkan skiljer sig åt mellan produktion i Sverige, Tyskland och Kina. Studien utgår från 13 Vestas LCA rapporter och använde en excelmodell för att utvärdera utsläppen av koldioxid. Resultatet visar att den geografiska platsen där produktionen sker har stor betydelse för de totala utsläppen, eftersom det är stor variation i energimix mellan olika länder. Överlag är det de stora stålkomponenterna som har störst bidrag till klimatpåverkan. Till följd av detta har havsbaserad vindkraft större klimatpåverkan än landbaserad, eftersom fundamentet primärt består av stål. Resultatet är dock begränsat, på grund av bristen av standardisering i rapportering och eftersom det är svårt att tillhandahålla specifika data gällande vindkraft.

Rådande situation med klimatförändringar och oroligheter i Europa kräver åtgärder för att kunna skifta från fossila bränslen och energikällor till mer hållbara alternativ. Elförbrukningen väntas öka signifikant i Sverige och ett alternativ för att tillgodose hållbar energi och klimatmål är utvecklingen av vindkraft. Satsningar sker alltmer på havsbaserad vindkraft eftersom det är goda vindförhållanden och mindre påverkan för människor i närområdet eftersom vindkraftverken kan placeras långt från kusten. I många fall är det projekteringsföretag, kommuner och politiker som beslutar placeringen av vindkraftverken. Ett problem som uppstår är när allmänheten anser att det uppstår störningar på grund av att vindkraftverken placeras i dess närhet och att de inte får deltaga i planeringsprocessen. Studien syftar till att hitta lämpliga platser för havsbaserad vindkraft utifrån metoderna medborgardialog och multikriterie-analys för att kunna integrera medborgarinflytande i planeringsprocessen. ”Mjuka kriterier” som ofta tas upp i sammanhang om vindkraft har tagits i beaktning och har skickats ut i en enkätundersökning för att få in vad som är viktigast för invånare i Gävle kommun. Dessa innefattar hur stor påverkan respondenterna uppfattas kunna påverkas av som till exempel ljud, utsikt och buller. Utifrån dessa kriterier fick respondenterna rangordna samtliga för att skapa en viktning till multikriterie-analysen. Beskrivande statistik på vad respondenterna är oroliga för att påverkas av vid byggnation av havsbaserad vindkraft togs fram för att styrka studiens legitimitet. Resultatet visar att det är en stor majoritet av respondenter som är positivt inställd mot vindkraft och att respondenter inte uttrycker någon signifikant oro. Metoden MKA med viktning av rank sum weights användes för att skapa olika kartor faktor- och restriktionskartor baserat på respondenternas svar samt en teknisk analys utifrån en omfattande litteraturstudie. Den tekniska analysen använder kriterier som havsdjup, avstånd till kraftstationer och hamnar som inte klassas som ”mjuka kriterier”. Resultatet visar att medborgardialogen påverkar vilken lokalisering vindkraftverken får jämfört med den tekniska analysen. En slutgiltig karta skapades för att visa var någonstans vindkraftparken kan hamna om båda delarna tillgodoses. Studien tyder på att ett större underlag för medborgardialog kunnat ge ett tydligare resultat samt att viss typ av data hade krävts för en ordentlig teknisk analys. Det nya som denna studie har utvecklat är en metod för att föra en medborgardialog gällande havsbaserad vindkraft och kvantifierat invånarnas åsikter till geografiska data. / The current situation with climate change and unrest in Europe requires measures to be able to switch from fossil fuels and energy sources to more sustainable alternatives. Electricity consumption is expected to increase significantly in Sweden and an alternative for meeting sustainable energy and climate goals is the development of wind power. Investments are increasingly being made in offshore wind power because it has adequate wind conditions and less impact for people in the immediate area since the turbines can be located far from the shore. In many cases, it is corporations, municipalities and politicians who decide on the location of the wind turbines. A problem that arises is when the public considers that disturbances occur due to the fact that the wind turbines are located in their vicinity and that they are not offered the possibility to participate in the planning process. The study aims to find suitable places for offshore wind power based on the methods citizen dialogue and multi-criteria analysis to be able to integrate citizen influence in the planning process. "Soft criteria" that are often raised in the context of wind power was taken into account and was included in a survey to address what is important for residents of Gävle municipality. These include how much impact the respondent is perceived to be affected by, such as sound, view and noise. Based on these criteria, the respondents were allowed to rank all of them in order to create a weighting for the multi-criteria analysis. Descriptive statistics based on what the respondents are worried about being affected by during the construction of offshore wind power were produced to prove the legitimacy of the study. The results show that a large majority of respondents are positive towards wind power and that respondents do not express any significant concern regarding the construction of offshore wind power. The MCA method with weighting method rank sum weights was used to create different factor and constraint maps based on the survey answers and a technical analysis based on an extensive literature study. The technical analysis uses criteria such as bathymetry, distance to power stations and ports that are not classified as "soft criteria". The results show that the citizen dialogue affects the location of the wind turbines compared to the technical analysis. A final map was created to show where the wind farm could end up if both parts are met. The study indicates that a more comprehensive citizen dialogue could have given a more concise result and that a certain type of data had been required for a more thorough technical analysis. The new thing that this study has developed is a method for conducting a citizen dialogue regarding offshore wind power and quantifying the inhabitants' opinions to geographical data.