WorldWideScience

Sample records for satellite-based offshore wind

  1. A Novel Sampling Method for Satellite-Based Offshore Wind Resource Estimation

    DEFF Research Database (Denmark)

    Badger, Merete; Badger, Jake; Hasager, Charlotte Bay

    advantage of satellite-based offshore wind resource assessment is the spatial information gained at high resolution from the satellite imagery. Limitations include the low sampling rate and the fixed acquisition times of satellite data. A new satellite scene is typically available every 3-4 days over...... wind class is used to weight the satellite-derived winds for the calculation of wind climatology. The applied selection and analysis of images should improve the reliability of wind climate estimates compared to random selection of images each given equal weighting....

  2. Satellite based wind resource assessment over the South China Sea

    DEFF Research Database (Denmark)

    Badger, Merete; Astrup, Poul; Hasager, Charlotte Bay

    2014-01-01

    modeling to develop procedures and best practices for satellite based wind resource assessment offshore. All existing satellite images from the Envisat Advanced SAR sensor by the European Space Agency (2002-12) have been collected over a domain in the South China Sea. Wind speed is first retrieved from...... description in order to calculate the mean wind climate at different levels up to 100 m. Time series from coarser-resolution satellite wind products i.e. the Special Sensor Microwave Imager (SSM/I) data are used to calculate the long-term temporal variability of the wind climate. This can be used...

  3. Offshore wind energy developments

    OpenAIRE

    Stolpe, Mathias; Buhl, Thomas; Sumer, B. Mutlu; Kiil, Søren; Holbøll, Joachim; Piirainen, Kalle

    2014-01-01

    This chapter will give a brief overview of a few of the activities within offshore wind energy research, specifically 1) Support structure optimization, 2) Blade coatings for wind turbines; 3) Scour protection of foundations, 4) Offshore HVDC and 5) Offshore wind services.

  4. Offshore wind energy developments

    DEFF Research Database (Denmark)

    Stolpe, Mathias; Buhl, Thomas; Sumer, B. Mutlu

    2014-01-01

    This chapter will give a brief overview of a few of the activities within offshore wind energy research, specifically 1) Support structure optimization, 2) Blade coatings for wind turbines; 3) Scour protection of foundations, 4) Offshore HVDC and 5) Offshore wind services....

  5. Offshore wind resource estimation for wind energy

    DEFF Research Database (Denmark)

    Hasager, Charlotte Bay; Badger, Merete; Mouche, A.

    2010-01-01

    Satellite remote sensing from active and passive microwave instruments is used to estimate the offshore wind resource in the Northern European Seas in the EU-Norsewind project. The satellite data include 8 years of Envisat ASAR, 10 years of QuikSCAT, and 23 years of SSM/I. The satellite observati......Satellite remote sensing from active and passive microwave instruments is used to estimate the offshore wind resource in the Northern European Seas in the EU-Norsewind project. The satellite data include 8 years of Envisat ASAR, 10 years of QuikSCAT, and 23 years of SSM/I. The satellite...... observations are compared to selected offshore meteorological masts in the Baltic Sea and North Sea. The overall aim of the Norsewind project is a state-of-the-art wind atlas at 100 m height. The satellite winds are all valid at 10 m above sea level. Extrapolation to higher heights is a challenge. Mesoscale...... modeling of the winds at hub height will be compared to data from wind lidars observing at 100 m above sea level. Plans are also to compare mesoscale model results and satellite-based estimates of the offshore wind resource....

  6. Session: Offshore wind

    Energy Technology Data Exchange (ETDEWEB)

    Gaarde, Jette; Ram, Bonnie

    2004-09-01

    This session at the Wind Energy and Birds/Bats workshop consisted of two presentations. Due to time constraints, a discussion period was not possible. The session addressed the current state of offshore wind energy development. The first presentation ''Monitoring Program and Results: Horns Rev and Nysted'' by Jette Gaarde summarized selected environmental studies conducted to date at operating offshore wind turbine projects in Denmark and lessons from other offshore wind developments in Europe. Wildlife impacts studies from the Danish sites focused on birds, fish, and mammals. The second presentation ''What has the U.S. Wind Industry Learned from the European Example'' by Bonnie Ram provided an update on current permit applications for offshore wind developments in the U.S. as well as lessons that may be drawn from the European experience.

  7. Offshore Wind Energy

    Energy Technology Data Exchange (ETDEWEB)

    Strach-Sonsalla, Mareike; Stammler, Matthias; Wenske, Jan; Jonkman, Jason; Vorpahl, Fabian

    2016-07-27

    In 1991, the Vindeby Offshore Wind Farm, the first offshore wind farm in the world, started feeding electricity to the grid off the coast of Lolland, Denmark. Since then, offshore wind energy has developed from this early experiment to a multibillion dollar market and an important pillar of worldwide renewable energy production. Unit sizes grew from 450 kW at Vindeby to the 7.5 MW-class offshore wind turbines (OWT ) that are currently (by October 2014) in the prototyping phase. This chapter gives an overview of the state of the art in offshore wind turbine (OWT) technology and introduces the principles of modeling and simulating an OWT. The OWT components -- including the rotor, nacelle, support structure, control system, and power electronics -- are introduced, and current technological challenges are presented. The OWT system dynamics and the environment (wind and ocean waves) are described from the perspective of OWT modelers and designers. Finally, an outlook on future technology is provided. The descriptions in this chapter are focused on a single OWT -- more precisely, a horizontal-axis wind turbine -- as a dynamic system. Offshore wind farms and wind farm effects are not described in detail in this chapter, but an introduction and further references are given.

  8. Offshore wind development research.

    Science.gov (United States)

    2014-04-01

    Offshore wind (OSW) development is a new undertaking in the US. This project is a response to : New Jerseys 2011 Energy Master Plan that envisions procuring 22.5% of the states power : originating from renewable sources by 2021. The Offshore Wi...

  9. Offshore Wind Power Data

    DEFF Research Database (Denmark)

    Cutululis, Nicolaos Antonio; Litong-Palima, Marisciel; Zeni, Lorenzo

    2012-01-01

    Wind power development scenarios are critical when trying to assess the impact of the demonstration at national and European level. The work described in this report had several objectives. The main objective was to prepare and deliver the proper input necessary for assessing the impact of Demo 4...... – Storm management at national and European level. For that, detailed scenarios for offshore wind power development by 2020 and 2030 were required. The aggregation level that is suitable for the analysis to be done is at wind farm level. Therefore, the scenarios for offshore wind power development offer...... details about the wind farms such as: capacity and coordinates. Since the focus is on the impact of storm fronts passage in Northen Europe, the offshore wind power scenarios were estimated only for the countries at North and Baltic Sea. The sources used are public sources, mentioned in the reference list...

  10. Offshore Wind Power

    DEFF Research Database (Denmark)

    Negra, Nicola Barberis

    The aim of the project is to investigate the influence of wind farms on the reliability of power systems. This task is particularly important for large offshore wind farms, because failure of a large wind farm might have significant influence on the balance of the power system, and because offshore...... Carlo simulation is used for these calculations: this method, in spite of an extended computation time, has shown flexibility in performing reliability studies, especially in case of wind generation, and a broad range of results which can be evaluated. The modelling is then extended to the entire power...... system considering conventional power plants, distributed generation based on wind energy and CHP technology as well as the load and transmission facilities. In particular, the different models are used to represent two well-known test systems, the RBTS and the IEEE-RTS, and to calculate...

  11. Offshore Wind Turbine Design

    DEFF Research Database (Denmark)

    Frandsen, Sten; Hansen, Erik Asp; Ibsen, Lars Bo

    2006-01-01

    Current offshore wind turbine design methods have matured to a 1st generation state, manifested in the draft of a possible standard, IEC 61400-3 (2005). It is now time to investigate the possibilities of improving existing methods. To do so in an efficient manner a clear identification of the most...... important uncertainty drivers specific for offshore wind turbine design loads is required. Describing the initial efforts in a Danish research project, the paper points to focal points for research and development. These are mainly: soil-structure interaction, improved modelling of wave loads from deep...

  12. 2016 Offshore Wind Market Report

    Energy Technology Data Exchange (ETDEWEB)

    Musial, Walter [National Renewable Energy Lab. (NREL), Golden, CO (United States); Beiter, Philipp [National Renewable Energy Lab. (NREL), Golden, CO (United States); Schwabe, Paul [National Renewable Energy Lab. (NREL), Golden, CO (United States); Tian, Tian [National Renewable Energy Lab. (NREL), Golden, CO (United States); Stehly, Tyler [National Renewable Energy Lab. (NREL), Golden, CO (United States); Spitsen, Paul [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2017-08-07

    The 2016 Offshore Wind Technologies Market Report is intended to provide stakeholders with quantitative information about the offshore wind market, technology, and cost trends in the United States and worldwide.

  13. Remote sensing observation used in offshore wind energy

    DEFF Research Database (Denmark)

    Hasager, Charlotte Bay; Pena Diaz, Alfredo; Christiansen, Merete Bruun

    2008-01-01

    Remote sensing observations used in offshore wind energy are described in three parts: ground-based techniques and applications, airborne techniques and applications, and satellite-based techniques and applications. Ground-based remote sensing of winds is relevant, in particular, for new large wind...

  14. Offshore Wind Farms

    DEFF Research Database (Denmark)

    Lundtang Petersen, Erik; Hasager, Charlotte Bay; Courtney, Michael

    2015-01-01

    as it is for the more traditional onshore wind power, which has been under development since the 1970s. However, offshore projects face extra technical challenges some of which requires in-depth scientific investigations. This article deals with some of the most outstanding challenges concerning the turbine structure......: the rotor, the nacelle, the tower, and the foundation. Further the determinations of the essential environmental conditions are treated: the wind field, the wave field, the sea current, and the soil conditions. The various options for grid connections, advantages, and disadvantages are discussed. Of special...

  15. Energy from Offshore Wind: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Musial, W.; Butterfield, S.; Ram, B.

    2006-02-01

    This paper provides an overview of the nascent offshore wind energy industry including a status of the commercial offshore industry and the technologies that will be needed for full market development.

  16. Overview of offshore wind farm configurations

    Science.gov (United States)

    Wei, Q.; Wu, B.; Xu, D.; Zargari, N. R.

    2017-11-01

    Offshore wind energy has been attracting great attention. Compared with onshore wind power systems, offshore wind power applications present significantly greater economic challenges mainly due to the required bulky and costly offshore substation. To lower the cost of offshore wind power systems, various configurations are proposed in both industry and academia. The present work investigates existing offshore wind farm configurations.

  17. Macrobenthos in offshore wind farms

    NARCIS (Netherlands)

    Jak, Robbert; Glorius, Sander

    2017-01-01

    Offshore wind farms potentially have an effect on the benthic ecosystem. Given the plans for large-scale development of offshore wind farms on the Dutch Continental Shelf (DCS), understanding these effects is relevant for policy and regulations regarding these developments. Because studying the

  18. Offshore Wind Turbine Foundation Design

    DEFF Research Database (Denmark)

    Passon, Patrik

    continued into 2015 it is even more important to drive down the costs of energy for renewable energy sources such as offshore wind energy in order to arrive at a sustainable future on a global level.Cost of energy reductions for offshore wind turbines (OWTs) can be achieved by optimizations on different......-wave correlations are typically subjected to sequential load calculation approaches in an iterative and collaborative process between foundation designer and wind turbine manufacturer. Involvement of these different design parties may be motivated by various aspects such as introduction of state-of-the-art design......Offshore wind energy has greatly matured during the last decade with an annually installed energy capacity exceeding 1 GW. A key factor for further large-scale development of offshore wind energy is a cost of energy reduction. Given for example the drop in oil price since summer 2014, which has...

  19. Offshore wind power in Finland

    Energy Technology Data Exchange (ETDEWEB)

    Holttinen, H. [VTT Energy, Espoo (Finland)

    1998-12-31

    The objectives of the project were to estimate the technical offshore wind power potential of the Gulf of Bothnia, with cost assessments, to study icing conditions and ice loads, and to design a foundation suitable for the environmental conditions. The technical offshore potential from Vaasa to Tornio is huge, more than 40 TWh/a, although the cost of offshore wind power is still higher than on land. Wind turbines have not previously been designed for the icing conditions found in Gulf of Bothnia and the recommendations for load cases and siting of megawatt-class turbines are an important result of the project. (orig.)

  20. Offshore wind farm repowering optimization

    DEFF Research Database (Denmark)

    Hou, Peng; Enevoldsen, Peter; Hu, Weihao

    2017-01-01

    Decommissioning is usually the last stage of the offshore wind farm life cycle. Due to the challenges of the decommissioning process, such as the impact on the marine environment, severe weather conditions, vessel limitations and lack of operational experience, the decommissioning strategy should...... be planned to avoid complications, which ultimately can cause radical changes to the levelized cost of energy (LCoE) and the wind farm owner's business case. Instead of dismantling, repowering may be a sustainable alternative solution to extend the lifetime of a wind farm. In this paper, the research...... is focused on optimization of offshore wind farm repowering, which is one option for the wind farm owner at end of life for the offshore wind farm. The LCoE is used as the evaluation index to identify whether it is economical to invest in such a way. In an optimized repowering strategy, different types...

  1. Wind energy in offshore grids

    DEFF Research Database (Denmark)

    Schröder, Sascha Thorsten

    and investment implications under different regulatory frameworks are a hitherto underrepresented research field. They are addressed by this thesis. Offshore grids between several countries combine the absorption of wind energy with international power trading. However, the inclusion into an offshore grid...... correcting its wind forecast errors in a specific onshore balancing group. An analytical approach with a transmission system operator and a wind farm as stakeholders illustrates resulting incentives for strategic behaviour. Depending on the regulatory regime, they may be inclined to announce more or less......This cumulative PhD thesis deals with wind integration in offshore grids from an economic point of view. It is composed of a generic part and eight papers. As the topic has mostly been analysed with a focus on topology and technical issues until now, market-operational questions in offshore grids...

  2. Foundations for offshore wind turbines.

    Science.gov (United States)

    Byrne, B W; Houlsby, G T

    2003-12-15

    An important engineering challenge of today, and a vital one for the future, is to develop and harvest alternative sources of energy. This is a firm priority in the UK, with the government setting a target of 10% of electricity from renewable sources by 2010. A component central to this commitment will be to harvest electrical power from the vast energy reserves offshore, through wind turbines or current or wave power generators. The most mature of these technologies is that of wind, as much technology transfer can be gained from onshore experience. Onshore wind farms, although supplying 'green energy', tend to provoke some objections on aesthetic grounds. These objections can be countered by locating the turbines offshore, where it will also be possible to install larger capacity turbines, thus maximizing the potential of each wind farm location. This paper explores some civil-engineering problems encountered for offshore wind turbines. A critical component is the connection of the structure to the ground, and in particular how the load applied to the structure is transferred safely to the surrounding soil. We review previous work on the design of offshore foundations, and then present some simple design calculations for sizing foundations and structures appropriate to the wind-turbine problem. We examine the deficiencies in the current design approaches, and the research currently under way to overcome these deficiencies. Designs must be improved so that these alternative energy sources can compete economically with traditional energy suppliers.

  3. Wind energy in offshore grids

    Energy Technology Data Exchange (ETDEWEB)

    Schroeder, S.T.

    2013-01-15

    This cumulative PhD thesis deals with wind integration in offshore grids from an economic point of view. It is composed of a generic part and eight papers. As the topic has mostly been analysed with a focus on topology and technical issues until now, market-operational questions in offshore grids and investment implications under different regulatory frameworks are a hitherto underrepresented research field. They are addressed by this thesis. Offshore grids between several countries combine the absorption of wind energy with international power trading. However, the inclusion into an offshore grid affects the economics of an offshore wind park. It is shown that the spot market income is lower if an offshore wind farm is placed in an interconnector and subject to nodal pricing instead of having a national affiliation. Moreover, congestion in the interconnector can prevent the wind farm from correcting its wind forecast errors in a specific onshore balancing group. An analytical approach with a transmission system operator and a wind farm as stakeholders illustrates resulting incentives for strategic behaviour. Depending on the regulatory regime, they may be inclined to announce more or less generation than expected at the closure of the day-ahead spot market. This can lead to a suboptimal utilisation of the infrastructure and associated socio-economic losses. These and possibly undesired reallocative effects between the parties can be avoided if the regulatory regime is adjusted to reflect special characteristics of offshore grids. With an operational real options approach, it is furthermore illustrated how different support schemes and connections to additional countries affect the investment case of an offshore wind farm and the income of the transmission system operator. The investment framework has also been addressed with a policy study about possible combinations of support schemes and international cooperation mechanisms between countries to achieve their

  4. Offshore Wind Energy Market Overview (Presentation)

    Energy Technology Data Exchange (ETDEWEB)

    Baring-Gould, I.

    2013-07-01

    This presentation describes the current international market conditions regarding offshore wind, including the breakdown of installation costs, how to reduce costs, and the physical siting considerations considered when planning offshore wind construction. The presentation offers several examples of international existing and planned offshore wind farm sites and compares existing international offshore resources with U.S. resources. The presentation covers future offshore wind trends and cites some challenges that the United States must overcome before it will be able to fully develop offshore wind sites.

  5. Offshore wind energy conversion systems

    Science.gov (United States)

    Kilar, L. A.; Stiller, P. H.; Anacona, D. F.

    The paper summarizes the findings of a comprehensive assessment of off-shore wind energy conversion systems. Eight generic types of support platforms are discussed, and their conceptual designs are given. Attention is given to the economics of such systems, emphasizing the busbar energy cost measures. Onshore energy costs are developed in terms of controlling environmental parameters, distance from shore and equipment type.

  6. National Offshore Wind Energy Grid Interconnection Study

    Energy Technology Data Exchange (ETDEWEB)

    Daniel, John P. [ABB Inc; Liu, Shu [ABB Inc; Ibanez, Eduardo [National Renewable Energy Laboratory; Pennock, Ken [AWS Truepower; Reed, Greg [University of Pittsburgh; Hanes, Spencer [Duke Energy

    2014-07-30

    The National Offshore Wind Energy Grid Interconnection Study (NOWEGIS) considers the availability and potential impacts of interconnecting large amounts of offshore wind energy into the transmission system of the lower 48 contiguous United States. A total of 54GW of offshore wind was assumed to be the target for the analyses conducted. A variety of issues are considered including: the anticipated staging of offshore wind; the offshore wind resource availability; offshore wind energy power production profiles; offshore wind variability; present and potential technologies for collection and delivery of offshore wind energy to the onshore grid; potential impacts to existing utility systems most likely to receive large amounts of offshore wind; and regulatory influences on offshore wind development. The technologies considered the reliability of various high-voltage ac (HVAC) and high-voltage dc (HVDC) technology options and configurations. The utility system impacts of GW-scale integration of offshore wind are considered from an operational steady-state perspective and from a regional and national production cost perspective.

  7. Offshore wind resources at Danish measurement sites

    Energy Technology Data Exchange (ETDEWEB)

    Barthelmie, R.J.; Courtney, M.S.; Lange, B.; Nielsen, M.; Sempreviva, A.M. [Risoe National Lab., Dept. of Wind Energy and Atmospheric Physics, Roskilde (Denmark); Svenson, J.; Olsen, F. [SEAS, Haslev (Denmark); Christensen, T. [Elsamprojekt, Fredericia (Denmark)

    1999-03-01

    In order to characterise wind and turbulence characteristics at prospective offshore wind energy sites, meteorological observations from a number of purpose-built offshore monitoring sites have been analyzed and compared with long wind speed time series. New analyses have been conducted on the data sets focussing on meteorology, turbulence, extreme winds and wind and wave interactions. Relationships between wind speed, turbulence and fetch are highly complex. Minimum turbulence intensity offshore is associated with wind speeds of about 12 m/s. At lower wind speeds, stability effects are important while at higher winds speeds wind and wave interactions appear to dominate. On average, turbulence intensity offshore at 48 m height is approximately 0.08 if no coastal effects are present. However, the effect of the coastal discontinuity persists in wind speed and turbulence characteristics for considerable distances offshore. The majority of the adjustment of appears to occur within 20 km of the coast. (au)

  8. Attitude and acceptance of offshore wind farms

    DEFF Research Database (Denmark)

    Ladenburg, Jacob; Möller, B.

    2011-01-01

    farms attributes on attitude towards offshore wind farms. The results point towards that the travel time and the attributes of the nearest offshore wind farm influence the attitude significantly. Travel time has mixed effects on the attitude, whilst offshore wind farms with many turbines generate more...... a novel contribution to this field. First of all, we give a thorough review of the studies that have analysed the relation between experience with wind turbines and attitude. In addition, we supplement the review by analysing the effect of travel distance to the nearest offshore wind farm and the wind...

  9. Wind model for offshore power simulation

    OpenAIRE

    Hervada Sala, Carme; Jarauta Bragulat, Eusebio; Gibergans Baguena, José; Buenestado Caballero, Pablo

    2015-01-01

    Offshore wind energy is an alternative energy source of increased interest. A large offshore wind farms have been planned or under construction, mainly in northern Europe. One of the points needed to be able to implement offshore projects is to characterize and model the wind for marine generation. Models are needed for the design of the most appropriate control strategies. Some attempts have been done to do so; recently these models are implemented under a wind turbine block set in Matlab/Si...

  10. Offshore Wind Energy in Denmark

    DEFF Research Database (Denmark)

    Möller, Bernd; Hong, Lixuan; Hvelplund, Frede

    availability of locations, driven by accelerating requirements of environmental concern, park size and public acceptance, is one important driver. Mounting risk of mega-projects and the infinite demand for renewable energy is another likely cause. The present paper addresses the scale of offshore wind parks......Offshore wind energy has developed in terms of turbine and project size, and currently undergoes a significant up-scaling to turbines and parks at greater distance to shore and deeper waters. Expectations to the positive effect of economies of scale on power production costs, however, have...... project size, location, ownership and costs is analysed. A scenario is proposed, which aims at locally owned smaller parks that may have several economic advantages but require a greater deal of tolerance and acceptance because of higher visual impact. Higher specific costs in some areas are outweighed...

  11. A novel floating offshore wind turbine concept

    DEFF Research Database (Denmark)

    Vita, Luca; Schmidt Paulsen, Uwe; Friis Pedersen, Troels

    2009-01-01

    This paper will present a novel concept of a floating offshore wind turbine. The new concept is intended for vertical-axis wind turbine technology. The main purpose is to increase simplicity and to reduce total costs of an installed offshore wind farm. The concept is intended for deep water...... and large size turbines....

  12. Reliability evaluation for offshore wind farms

    DEFF Research Database (Denmark)

    Zhao, Menghua; Blåbjerg, Frede; Chen, Zhe

    2005-01-01

    In this paper, a new reliability index - Loss Of Generation Ratio Probability (LOGRP) is proposed for evaluating the reliability of an electrical system for offshore wind farms, which emphasizes the design of wind farms rather than the adequacy for specific load demand. A practical method...... to calculate LOGRP of offshore wind farms is proposed and evaluated....

  13. Offshore wind options for 2013; Offshore wind kansen voor 2013

    Energy Technology Data Exchange (ETDEWEB)

    Van der Meij-Kranendonk, J.

    2012-11-15

    In the USA researchers and companies are busy to the make knowledge and experiences gained elsewhere in the world suitable for the American market and to increase new knowledge in their own country. A brief overview is given of the activities in the US with regard to offshore wind energy [Dutch] Amerikaanse onderzoekers en bedrijven zijn druk bezig om de kennis en ervaring die opgedaan is elders in de wereld geschikt te maken voor de Amerikaanse markt en om nieuwe kennis op te doen in eigen land.

  14. An Overview of Offshore Wind Farm Design

    DEFF Research Database (Denmark)

    Giebel, Gregor; Hasager, Charlotte Bay

    2016-01-01

    For offshore wind energy to be viable, the design of wind turbines is not the only important factor—rather, the design of wind farms is also crucial. The current chapter discusses the challenges of designing an optimum wind farm and identifies the various factors that need to be considered. Lastly......, the chapter presents the novel EERA-DTOC tool for designing offshore wind farm clusters....

  15. Offshore Wind Energy Resource Assessment for Alaska

    Energy Technology Data Exchange (ETDEWEB)

    Doubrawa Moreira, Paula [National Renewable Energy Lab. (NREL), Golden, CO (United States); Scott, George N. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Musial, Walter D. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Kilcher, Levi F. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Draxl, Caroline [National Renewable Energy Lab. (NREL), Golden, CO (United States); Lantz, Eric J. [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2018-01-02

    This report quantifies Alaska's offshore wind resource capacity while focusing on its unique nature. It is a supplement to the existing U.S. Offshore Wind Resource Assessment, which evaluated the offshore wind resource for all other U.S. states. Together, these reports provide the foundation for the nation's offshore wind value proposition. Both studies were developed by the National Renewable Energy Laboratory. The analysis presented herein represents the first quantitative evidence of the offshore wind energy potential of Alaska. The technical offshore wind resource area in Alaska is larger than the technical offshore resource area of all other coastal U.S. states combined. Despite the abundant wind resource available, significant challenges inhibit large-scale offshore wind deployment in Alaska, such as the remoteness of the resource, its distance from load centers, and the wealth of land available for onshore wind development. Throughout this report, the energy landscape of Alaska is reviewed and a resource assessment analysis is performed in terms of gross and technical offshore capacity and energy potential.

  16. Switching overvoltages in offshore wind power grids

    DEFF Research Database (Denmark)

    Arana Aristi, Ivan

    and cables are presented. In Chapter 4 results from time domain measurements and simulations of switching operations in offshore wind power grids are described. Specifically, switching operations on a single wind turbine, the collection grid, the export system and the external grid measured in several real...... offshore wind farms are shown together with simulation results. Switching operations in offshore wind power grids can be simulated with different electromagnetic transient programs. Different programs were used in the project and compared results are included in Chapter 4. Also in Chapter 4 different...... models were used inthe same program, and in several switching operations sensitivity analysis was made. General models and methods to study switching transient overvoltages in offshore wind farms have been shown in this work. These models and methods are valid for all offshore wind farms, or other...

  17. Site selection for offshore wind farms along the Indian coast

    Digital Repository Service at National Institute of Oceanography (India)

    ManiMurali, R.; Vidya, P.J.; Modi, P.; JayaKumar, S.

    This study deals with locating the potential sites for offshore wind farms and also deals with feasibility of installing offshore wind farms through scientific examination of the requirements along the coast of India Offshore wind energy is almost...

  18. CFD for wind and tidal offshore turbines

    CERN Document Server

    Montlaur, Adeline

    2015-01-01

    The book encompasses novel CFD techniques to compute offshore wind and tidal applications. Computational fluid dynamics (CFD) techniques are regarded as the main design tool to explore the new engineering challenges presented by offshore wind and tidal turbines for energy generation. The difficulty and costs of undertaking experimental tests in offshore environments have increased the interest in the field of CFD which is used to design appropriate turbines and blades, understand fluid flow physical phenomena associated with offshore environments, predict power production or characterise offshore environments, amongst other topics.

  19. Optimized power generation in offshore wind parks

    NARCIS (Netherlands)

    Oliveira Filho, J. de; Papp, Z.

    2011-01-01

    Electricity generation on offshore wind parks has an increasing economic importance - the European Commission foresees that 12% of the wind energy will be produced on offshore installations by 2020, and this share is likely to increase further in the following years. However, the continuously

  20. Far offshore wind conditions in scope of wind energy

    NARCIS (Netherlands)

    Holtslag, M.C.

    2016-01-01

    Far offshore atmospheric conditions are favourable for wind energy purposes since mean wind speeds are relatively high (i.e., high power production) while turbulence levels are relatively low (i.e., less fatigue loads) compared to onshore conditions. Offshore wind energy, however, is still expensive

  1. 2016 Offshore Wind Technologies Market Report

    Energy Technology Data Exchange (ETDEWEB)

    Musial, Walter; Beiter, Philipp; Schwabe, Paul; Tian, Tian; Stehly, Tyler; Spitsen, Paul; Robertson, Amy; Gevorgian, Vahan

    2017-08-08

    The 2016 Offshore Wind Technologies Market Report was developed by the National Renewable Energy Laboratory (NREL) for the U.S. Department of Energy (DOE) and is intended to provide offshore wind policymakers, regulators, developers, researchers, engineers, financiers, and supply chain participants, with quantitative information about the offshore wind market, technology, and cost trends in the United States and worldwide. In particular, this report is intended to provide detailed information on the domestic offshore wind industry to provide context to help navigate technical and market barriers and opportunities. The scope of the report covers the status of the 111 operating offshore wind projects in the global fleet through December 31, 2016, and provides the status and analysis on a broader pipeline of 593 projects at some stage of development. In addition, this report provides a wider assessment of domestic developments and events through the second quarter of 2017 to provide a more up-to-date discussion of this dynamically evolving industry.

  2. Offshore wind energy potential in China

    DEFF Research Database (Denmark)

    Hong, Lixuan; Möller, Bernd

    2011-01-01

    This paper investigates available offshore wind energy resources in China’s exclusive economic zone (EEZ) with the aid of a Geographical Information System (GIS), which allows the influence of technical, spatial and economic constraints on offshore wind resources being reflected in a continuous...... space. Geospatial supply curves and spatial distribution of levelised production cost (LPC) are developed, which provide information on the available potential of offshore wind energy at or below a given cost, and its corresponding geographical locations. The GIS-based models also reflect the impacts...... of each spatial constraint as well as various scenarios of spatial constraints on marginal production costs of offshore wind energy. Furthermore, the impacts of differing Feed-in-tariff (FIT) standards on the economic potential are calculated. It confirms that economic potential of offshore wind energy...

  3. Offshore Wind Market and Economic Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Hamilton, Bruce Duncan [Navigant Consulting, Inc., Chicago, IL (United States)

    2014-08-27

    This report is the third annual assessment of the U.S. offshore wind market. It includes the following major sections: Section 1: key data on developments in the offshore wind technology sector and the global development of offshore wind projects, with a particular focus on progress in the United States; Section 2: analysis of policy developments at the federal and state levels that have been effective in advancing offshore wind deployment in the United States; Section 3: analysis of actual and projected economic impact, including regional development and job creation; Section 4: analysis of developments in relevant sectors of the economy with the potential to affect offshore wind deployment in the United States

  4. Wakes in large offshore wind farms

    DEFF Research Database (Denmark)

    Berthelmie, Rebecca J.; Frandsen, Sten Tronæs; Rathmann, Ole

    2008-01-01

    Power losses due to wind turbine wakes are of the order of 10 and 20% of total power output in large wind farms. The focus of this research carried out within the EC funded UPWIND project is wind speed and turbulence modelling for large wind farms/wind turbines in complex terrain and offshore...... is for five turbines in flat terrain. Finally a complex terrain wind farm will be modelled and compared with observations. For offshore wind farms, the focus is on cases at the Horns Rev wind farm which indicate wind farm models require modification to reduce under-prediction of wake losses while CFD models...... in order to optimise wind farm layouts to reduce wake losses and loads. For complex terrain, a set of three evaluations is underway. The first is a model comparison for a Gaussian Hill where CFD models and wind farm models are being compared for the case of one hilltop wind turbine. The next case...

  5. Offshore wind energy. Status and perspectives

    Energy Technology Data Exchange (ETDEWEB)

    Gassner, Holger [RWE Innogy GmbH, Essen (Germany). Strategy and Regulatory Affairs

    2014-06-01

    Offshore wind power belongs to those renewables technologies, which increased tremendously in recent years and with a high potential for further growth. Offshore wind energy can be utilised at high full load hours and is therefore an important part for the future energy system and the growth of renewable energy. By realising a huge potential for cost saving, wind power economy will increase in the future. (orig.)

  6. Offshore wind turbines reliability, availability and maintenance

    CERN Document Server

    Tavner, Peter

    2012-01-01

    The first book to specifically focus on offshore wind turbine technology and which addresses practically wind turbine reliability and availability. The book draws on the author's experience of power generation reliability and availability and the condition monitoring of that plant to describe the problems facing the developers of offshore wind farms and the solutions available to them to raise availability, reduce cost of energy and improve through life cost.

  7. Offshore Wind Energy Systems Engineering Curriculum Development

    Energy Technology Data Exchange (ETDEWEB)

    McGowan, Jon G. [Univ. of Massachusetts, Amherst, MA (United States); Manwell, James F. [Univ. of Massachusetts, Amherst, MA (United States); Lackner, Matthew A. [Univ. of Massachusetts, Amherst, MA (United States)

    2012-12-31

    Utility-scale electricity produced from offshore wind farms has the potential to contribute significantly to the energy production of the United States. In order for the U.S. to rapidly develop these abundant resources, knowledgeable scientists and engineers with sound understanding of offshore wind energy systems are critical. This report summarizes the development of an upper-level engineering course in "Offshore Wind Energy Systems Engineering." This course is designed to provide students with a comprehensive knowledge of both the technical challenges of offshore wind energy and the practical regulatory, permitting, and planning aspects of developing offshore wind farms in the U.S. This course was offered on a pilot basis in 2011 at the University of Massachusetts and the National Renewable Energy Laboratory (NREL), TU Delft, and GL Garrad Hassan have reviewed its content. As summarized in this report, the course consists of 17 separate topic areas emphasizing appropriate engineering fundamentals as well as development, planning, and regulatory issues. In addition to the course summary, the report gives the details of a public Internet site where references and related course material can be obtained. This course will fill a pressing need for the education and training of the U.S. workforce in this critically important area. Fundamentally, this course will be unique due to two attributes: an emphasis on the engineering and technical aspects of offshore wind energy systems, and a focus on offshore wind energy issues specific to the United States.

  8. Offshore Wind Power at Rough Sea

    DEFF Research Database (Denmark)

    Petersen, Kristian Rasmus; Madsen, Erik Skov; Bilberg, Arne

    2013-01-01

    This study compare the current operations and maintenance issues of one offshore wind park at very rough sea conditions and two onshore wind parks. Through a detailed data analysis and case studies this study identifies how improvements have been made in maintenance of large wind turbines. Howeve......, the study has also revealed the need for new maintenance models including a shift from breakdown and preventive maintenances and towards more predictive maintenance to reduce the cost of energy for offshore wind energy installations in the future.......This study compare the current operations and maintenance issues of one offshore wind park at very rough sea conditions and two onshore wind parks. Through a detailed data analysis and case studies this study identifies how improvements have been made in maintenance of large wind turbines. However...

  9. Offshore Wind Power Planning in Korea

    DEFF Research Database (Denmark)

    Seo, Chul Soo; Cha, Seung-Tae; Park, Sang Ho

    2012-01-01

    Wind power generation is globally recognized as the most universal and reliable form of renewable energy. Korea is currently depending mostly on coal and petroleum to generate electrical power and is now trying to replace them with renewable energy such as offshore wind power generation. To make...... this possible, Korea has announced the National offshore power roadmap and is now in pursuit. However, large scale offshore wind farms can incur many problems, such as power quality problems, when connecting to a power system.[1][2] Thus, KEPCO is on the process of a research study to evaluate the effects...

  10. Offshore wind market outlook in Northern Europe

    Energy Technology Data Exchange (ETDEWEB)

    Pimenta de Miranda, Wilfried; Trulsson, Ola; Ekloef, Eva-Britt; Niemenen, Karel

    2010-08-15

    After more than 10 years of slow developments, the offshore wind market is now accelerating. Thanks to a sustained political drive from UK and Germany, the rest of Northern Europe is now following the path as offshore wind is being recognized as one of the key resources available to the EU to meet its renewable energy ambitions. Exposed to increasing technical issues, rising costs and the financial crisis, lessons learned are now being shared and integrated throughout Europe and appropriate regulatory and planning reforms are now being deployed to speed the deployment of offshore wind. (Author)

  11. Fatigue Reliability of Offshore Wind Turbine Systems

    DEFF Research Database (Denmark)

    Marquez-Dominguez, Sergio; Sørensen, John Dalsgaard

    2012-01-01

    Optimization of the design of offshore wind turbine substructures with respect to fatigue loads is an important issue in offshore wind energy. A stochastic model is developed for assessing the fatigue failure reliability. This model can be used for direct probabilistic design and for calibration...... of appropriate partial safety factors / fatigue design factors (FDF) for steel substructures of offshore wind turbines (OWTs). The fatigue life is modeled by the SN approach. Design and limit state equations are established based on the accumulated fatigue damage. The acceptable reliability level for optimal...

  12. Offshore winds mapped from satellite remote sensing

    DEFF Research Database (Denmark)

    Hasager, Charlotte Bay

    2014-01-01

    the uncertainty on the model results on the offshore wind resource, it is necessary to compare model results with observations. Observations from ground-based wind lidar and satellite remote sensing are the two main technologies that can provide new types of offshore wind data at relatively low cost....... The advantages of microwave satellite remote sensing are 1) horizontal spatial coverage, 2) long data archives and 3) high spatial detail both in the coastal zone and of far-field wind farm wake. Passive microwave ocean wind speed data are available since 1987 with up to 6 observations per day with near...

  13. Harmonics in large offshore wind farms

    DEFF Research Database (Denmark)

    Kocewiak, Lukasz Hubert

    to this fact, the research project owes its uniqueness and contributes new insight to the academia. It is proven that an analysis of such systems as large offshore wind farms considers many aspects related to extended and accurate models, complex measurement campaigns and of course appropriate and more...... resonances within the low frequency range. This can significantly affect overall system stability. Therefore, the analysis and design optimization of large offshore wind farms are more complex than smaller onshore wind farms. Nowadays, wind turbines are complex devices equipped with the newest technologies......The number of wind turbines with full converters in the MW range used in large offshore wind farms is rapidly increasing. They are connected through a widespread MV cable network with practicably no consumption and connected to the transmission system by long HV cables. This represents new...

  14. Floating Foundations for Offshore Wind Turbines

    DEFF Research Database (Denmark)

    Andersen, Morten Thøtt

    -scale prototypes to full-scale pre-commercial wind parks. This thesis explores different aspects of numerical and physical modeling of floating offshore wind turbines. Numerical investigations, validated by physical test data, are used to highlight some of the implications of modeling these highly coupled aero......The concept of harnessing the power of the wind dates all the way back to the first ships traversing the seas. Later, windmills enabled the use of wind power for industrial purposes. Since then, technology has allowed the production of clean renewable energy through the use of wind turbines....... These turbines have traditionally been placed on land, but several factors have urged a move to offshore locations. Now the boundaries are being pushed into deeper and deeper waters, where the idea of floating offshore wind turbines has emerged. In less than a decade, these have gone from scattered small...

  15. DOD Offshore Wind Mission Compatibility Assessments

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set represents the results of analyses conducted by the Department of Defense to assess the compatibility of offshore wind development with military assets...

  16. Engineering Challenges for Floating Offshore Wind Turbines

    Energy Technology Data Exchange (ETDEWEB)

    Butterfield, S.; Musial, W.; Jonkman, J.; Sclavounos, P.

    2007-09-01

    The major objective of this paper is to survey the technical challenges that must be overcome to develop deepwater offshore wind energy technologies and to provide a framework from which the first-order economics can be assessed.

  17. Effects of offshore wind farms on birds

    DEFF Research Database (Denmark)

    Petersen, Ib Krag; Fox, Anthony David; Desholm, Mark

    På konferencen "Offshore Wind Energy Development Site Assessment and Characterization: Evaluation of the Current Status and European Experience" blev der gjort rede for danske erfaringer med effekten af havvindmølleparker på havfugle.......På konferencen "Offshore Wind Energy Development Site Assessment and Characterization: Evaluation of the Current Status and European Experience" blev der gjort rede for danske erfaringer med effekten af havvindmølleparker på havfugle....

  18. 2014 Offshore Wind Market and Economic Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Hamilton, Bruce [Navigant Consulting, Inc., Burlington, MA (United States)

    2014-08-25

    The objective of this report is to provide a comprehensive annual assessment of the U.S. offshore wind market.This 3rd annual report focuses on new developments that have occurred in 2014. The report provides stakeholders with a reliable and consistent data source addressing entry barriers and U.S. competitiveness in the offshore wind market. Available for download are both the full report and the report's underlying data.

  19. New perspectives in offshore wind energy

    Science.gov (United States)

    Failla, Giuseppe; Arena, Felice

    2015-01-01

    The design of offshore wind turbines is one of the most fascinating challenges in renewable energy. Meeting the objective of increasing power production with reduced installation and maintenance costs requires a multi-disciplinary approach, bringing together expertise in different fields of engineering. The purpose of this theme issue is to offer a broad perspective on some crucial aspects of offshore wind turbines design, discussing the state of the art and presenting recent theoretical and experimental studies. PMID:25583869

  20. Harmonic Aspects of Offshore Wind Farms

    DEFF Research Database (Denmark)

    Kocewiak, Lukasz Hubert; Bak, Claus Leth; Hjerrild, Jesper

    2010-01-01

    This paper presents the aim, the work and the findings of a PhD project entitled "Harmonics in Large Offshore Wind Farms". It focuses on the importance of harmonic analysis in order to obtain a better performance of future wind farms. The topic is investigated by the PhD project at Aalborg...... University (AAU) and DONG Energy. The objective of the project is to improve and understand the nature of harmonic emission and propagation in wind farms (WFs), based on available information, measurement data and simulation tools. The aim of the project is to obtain validated models and analysis methods...... of offshore wind farm (OWF) systems....

  1. RBI Optimization of Offshore Wind Turbines

    DEFF Research Database (Denmark)

    Ramírez, José G. Rangel; Sørensen, John Dalsgaard

    2009-01-01

    support structure is a steel structure consisting of a tower and a monopile, tripod or jacket type foundation. This paper considers aspects of inspection and maintenance planning of fatigue prone details in jacket and tripod type of wind turbine support structures. Based on risk-based inspection planning...... methods for oil & gas installations, a framework for optimal inspection and maintenance planning of offshore wind turbines is presented. Special aspects for offshore wind turbines considered are the fatigue loading characteristics where usually the wind loading are dominating the wave loading, wake...

  2. Lake Michigan Offshore Wind Feasibility Assessment

    Energy Technology Data Exchange (ETDEWEB)

    Boezaart, Arnold [GVSU; Edmonson, James [GVSU; Standridge, Charles [GVSU; Pervez, Nahid [GVSU; Desai, Neel [University of Michigan; Williams, Bruce [University of Delaware; Clark, Aaron [GVSU; Zeitler, David [GVSU; Kendall, Scott [GVSU; Biddanda, Bopi [GVSU; Steinman, Alan [GVSU; Klatt, Brian [Michigan State University; Gehring, J. L. [Michigan State University; Walter, K. [Michigan State University; Nordman, Erik E. [GVSU

    2014-06-30

    The purpose of this project was to conduct the first comprehensive offshore wind assessment over Lake Michigan and to advance the body of knowledge needed to support future commercial wind energy development on the Great Lakes. The project involved evaluation and selection of emerging wind measurement technology and the permitting, installation and operation of the first mid-lake wind assessment meteorological (MET) facilities in Michigan’s Great Lakes. In addition, the project provided the first opportunity to deploy and field test floating LIDAR and Laser Wind Sensor (LWS) technology, and important research related equipment key to the sitting and permitting of future offshore wind energy development in accordance with public participation guidelines established by the Michigan Great Lakes Wind Council (GLOW). The project created opportunities for public dialogue and community education about offshore wind resource management and continued the dialogue to foster Great Lake wind resource utilization consistent with the focus of the GLOW Council. The technology proved to be effective, affordable, mobile, and the methods of data measurement accurate. The public benefited from a substantial increase in knowledge of the wind resources over Lake Michigan and gained insights about the potential environmental impacts of offshore wind turbine placements in the future. The unique first ever hub height wind resource assessment using LWS technology over water and development of related research data along with the permitting, sitting, and deployment of the WindSentinel MET buoy has captured public attention and has helped to increase awareness of the potential of future offshore wind energy development on the Great Lakes. Specifically, this project supported the acquisition and operation of a WindSentinel (WS) MET wind assessment buoy, and associated research for 549 days over multiple years at three locations on Lake Michigan. Four research objectives were defined for the

  3. Wind shear extremes at possible offshore wind turbine locations

    DEFF Research Database (Denmark)

    Hansen, Kurt Schaldemose; Larsen, Gunner Chr.

    2003-01-01

    Positive and negative short-term extreme wind shear distributions (conditioned on the mean wind speed) are determined and compared for a number of offshore sites. The analysis is based on rapidly sampled field measurements (1-8 Hz) extracted from the "Database on Wind Characteristics" (www.windda...... seems to be rather conservative for an offshore location, compared to the estimated values based on measurements....

  4. Offshore wind power in the Aegean Sea

    DEFF Research Database (Denmark)

    Hasager, Charlotte Bay; Badger, Merete; Hahmann, Andrea N.

    winds (SDW). It is planned to combine the Envisat wind fields with Sentinel-1a and Sentinel-1b wind fields to further detail the offshore wind resource within the New European Wind Atlas. The work is in progress. Sentinel-1a images are processed at DTU Wind Energy near-real-time and we are updating our...... wind resource software. A service-based on satellite SAR-derived winds for wind resource estimation is available at DTU Wind Energy. The project was supported by ESA ResGrow and satellite data from ESA Envisat and Copernicus Sentinel-1....... hub heights at around 100 m using a combination of satellite wind fields and the long-term climate of atmospheric stability from the mesoscale model (Badger et al. 2016). The result of the mean wind speed at hub-height for the Aegean Sea is shown in Figure 1. The map shows the stability dependent...

  5. Design Load Basis for Offshore Wind turbines

    DEFF Research Database (Denmark)

    Natarajan, Anand; Hansen, Morten Hartvig; Wang, Shaofeng

    2016-01-01

    DTU Wind Energy is not designing and manufacturing wind turbines and does therefore not need a Design Load Basis (DLB) that is accepted by a certification body. However, to assess the load consequences of innovative features and devices added to existing offshore turbine concepts or new offshore...... turbine concept developed in our research, it is useful to have a full DLB that follows the current design standard and is representative of a general DLB used by the industry. It will set a standard for the offshore wind turbine design load evaluations performed at DTU Wind Energy, which is aligned...... with the challenges faced by the industry and therefore ensures that our research continues to have a strong foundation in this interaction. Furthermore, the use of a full DLB that follows the current standard can improve and increase the feedback from the research at DTU Wind Energy to the international...

  6. Design tool for offshore wind farm clusters

    DEFF Research Database (Denmark)

    Hasager, Charlotte Bay; Giebel, Gregor; Waldl, Igor

    2015-01-01

    The Design Tool for Offshore wind farm Clusters (DTOC) is a software tool to facilitate the optimised design of both, individual and clusters of offshore wind farms. DTOC is developed with the support of an EC funded FP7 project with contributions from science partners from the European Energy...... Research Alliance (EERA) and a number of industrial partners. The approach has been to develop a robust, efficient, easy to use and flexible tool, which integrates software relevant for planning offshore wind farms and wind farm clusters and supports the user with a clear optimization work flow...... is developed within the project using open interface standards and is now available as the commercial software product Wind&Economy....

  7. Design off-shore wind climate

    Energy Technology Data Exchange (ETDEWEB)

    Larsen, G.C.; Joergensen, H.E. [Risoe National Lab., Wind Energy and Atmospheric Physics Dept., Roskilde (Denmark)

    1999-03-01

    Specific recommendations of off-shore turbulence intensities, applicable for design purposes, are lacking in the present IEC-code. The present off-shore wind climate analysis presents the distribution of the turbulence standard deviation around the mean turbulence standard deviation, conditioned on the mean wind speed. Measured distributions, based on a huge amount of measuring data from two shallow water off-shore sites, are parameterized by fitting to a three parameter Weibull distribution. Combining a simple heuristic load model with the parameterized probability density functions of the turbulence standard deviations, an empirical off-shore design turbulence intensity is evaluated that in average yields the same fatigue damage as the distributed turbulence intensity. The proposed off-shore design turbulence intensity is, within the IEC code framework, applicable for extreme as well as for fatigue load determination. (au)

  8. Wind Statistics Offshore based on Satellite Images

    DEFF Research Database (Denmark)

    Hasager, Charlotte Bay; Mouche, Alexis; Badger, Merete

    2009-01-01

    -based observations become available. At present preliminary results are obtained using the routine methods. The first step in the process is to retrieve raw SAR data, calibrate the images and use a priori wind direction as input to the geophysical model function. From this process the wind speed maps are produced....... Results comparing satellite scatterometer winds to offshore meteorological observations have shown good results, and more comparisons are planned in this respect during the Norsewind project....

  9. Dynamic Response Analysis of an Offshore Wind Turbine

    OpenAIRE

    Li, Yu

    2011-01-01

    The offshore wind power is an attractive renewable energy resource. To improve the wind power generation capacity, there is a strong desire for offshore wind turbine to go to deep waters. For offshore fixed wind turbine, stronger foundation like jacket structure has a good applicability for deeper water depth. A 70-meters jacket substructure for offshore wind turbine is designed. This thesis focuses on the dynamic structural response analysis of this jacket substructure, with a particular foc...

  10. Exploring the offshore wind farm far field

    Science.gov (United States)

    Platis, Andreas; Emeis, Stefan; Siedersleben, Simon; Neumann, Tom; Canadillas, Beatriz; Lampert, Astrid; Djath, Nathacha; Schulz-Stellenfleth, Johannes; Bärfuss, Konrad; Bange, Jens

    2017-04-01

    Offshore wind farms contribute a considerable part of today's production of renewable electric energy. In the last years a massive built-up in offshore wind energy farms has occurred with a concentration of the wind farms in group and cluster. This arrangement affects one another through increased wake losses. The German Government is presently funding a research project called WIPAFF (WInd PArk Far Field) which is dedicated to the the analysis of properties and impacts of offshore wind park far fields and wake losses. The focus is on the analysis of wind farm wakes, their interaction among each other and their regional climate impact. This is done by in-situ, extensive aircraft and satellite measurements and by operating meso-scale wind field models and an analytical wind farm model. We will present this project and show preliminary results of the the first in situ evidence by airborne measurements of these wakes behind off shore windfarms with a wind deficit zones and enhanced turbulence.

  11. Offshore wind mapping Mediterranean area using SAR

    DEFF Research Database (Denmark)

    Calaudi, Rosamaria; Arena, Felice; Badger, Merete

    2013-01-01

    Satellite observations of the ocean surface, for example from Synthetic Aperture Radars (SAR), provide information about the spatial wind variability over large areas. This is of special interest in the Mediterranean Sea, where spatial wind information is only provided by sparse buoys, often...... with long periods of missing data. Here, we focus on evaluating the use of SAR for offshore wind mapping. Preliminary results from the analysis of SAR-based ocean winds in Mediterranean areas show interesting large scale wind flow features consistent with results from previous studies using numerical models...

  12. New perspectives in offshore wind energy.

    Science.gov (United States)

    Failla, Giuseppe; Arena, Felice

    2015-02-28

    The design of offshore wind turbines is one of the most fascinating challenges in renewable energy. Meeting the objective of increasing power production with reduced installation and maintenance costs requires a multi-disciplinary approach, bringing together expertise in different fields of engineering. The purpose of this theme issue is to offer a broad perspective on some crucial aspects of offshore wind turbines design, discussing the state of the art and presenting recent theoretical and experimental studies. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

  13. Strong winds and waves offshore

    DEFF Research Database (Denmark)

    Larsén, Xiaoli Guo

    2016-01-01

    This report is prepared for Statoil, with the intention to introdu e DTU Wind Energy's ongoing resear h a tivities on o shore extreme wind and wave onditions. The purpose is to share our re ent ndings and to establish possible further ollaboration with Statoil. The fo us of this report is on the ......This report is prepared for Statoil, with the intention to introdu e DTU Wind Energy's ongoing resear h a tivities on o shore extreme wind and wave onditions. The purpose is to share our re ent ndings and to establish possible further ollaboration with Statoil. The fo us of this report...... is on the meteorologi al and o eani onditions related to storm winds and waves over the North Sea. With regard to the o shore wind energy appli ation, the parameters addressed here in lude: extreme wind and extreme waves, storm wind and waves and turbulen e issues for o shore onditions....

  14. National Offshore Wind Energy Grid Interconnection Study Executive Summary

    Energy Technology Data Exchange (ETDEWEB)

    Daniel, John P. [ABB, Inc., Cary, NC (United States); Liu, Shu [ABB, Inc., Cary, NC (United States); Ibanez, Eduardo [National Renewable Energy Lab. (NREL), Golden, CO (United States); Pennock, Ken [AWS Truepower, Albany, NY (United States); Reed, Gregory [Univ. of Pittsburgh, PA (United States); Hanes, Spencer [Duke Energy, Charlotte, NC (United States)

    2014-07-30

    The National Offshore Wind Energy Grid Interconnection Study (NOWEGIS) considers the availability and potential impacts of interconnecting large amounts of offshore wind energy into the transmission system of the lower 48 contiguous United States.

  15. National Offshore Wind Energy Grid Interconnection Study Full Report

    Energy Technology Data Exchange (ETDEWEB)

    Daniel, John P. [ABB, Inc., Cary, NC (United States); Liu, Shu [ABB, Inc., Cary, NC (United States); Ibanez, Eduardo [National Renewable Energy Lab. (NREL), Golden, CO (United States); Pennock, Ken [AWS Truepower, Albany, NY (United States); Reed, Gregory [Univ. of Pittsburgh, PA (United States); Hanes, Spencer [Duke Energy, Charlotte, NC (United States)

    2014-07-30

    The National Offshore Wind Energy Grid Interconnection Study (NOWEGIS) considers the availability and potential impacts of interconnecting large amounts of offshore wind energy into the transmission system of the lower 48 contiguous United States.

  16. Examining the utility of satellite-based wind sheltering estimates for lake hydrodynamic modeling

    Science.gov (United States)

    Van Den Hoek, Jamon; Read, Jordan S.; Winslow, Luke A.; Montesano, Paul; Markfort, Corey D.

    2015-01-01

    Satellite-based measurements of vegetation canopy structure have been in common use for the last decade but have never been used to estimate canopy's impact on wind sheltering of individual lakes. Wind sheltering is caused by slower winds in the wake of topography and shoreline obstacles (e.g. forest canopy) and influences heat loss and the flux of wind-driven mixing energy into lakes, which control lake temperatures and indirectly structure lake ecosystem processes, including carbon cycling and thermal habitat partitioning. Lakeshore wind sheltering has often been parameterized by lake surface area but such empirical relationships are only based on forested lakeshores and overlook the contributions of local land cover and terrain to wind sheltering. This study is the first to examine the utility of satellite imagery-derived broad-scale estimates of wind sheltering across a diversity of land covers. Using 30 m spatial resolution ASTER GDEM2 elevation data, the mean sheltering height, hs, being the combination of local topographic rise and canopy height above the lake surface, is calculated within 100 m-wide buffers surrounding 76,000 lakes in the U.S. state of Wisconsin. Uncertainty of GDEM2-derived hs was compared to SRTM-, high-resolution G-LiHT lidar-, and ICESat-derived estimates of hs, respective influences of land cover type and buffer width on hsare examined; and the effect of including satellite-based hs on the accuracy of a statewide lake hydrodynamic model was discussed. Though GDEM2 hs uncertainty was comparable to or better than other satellite-based measures of hs, its higher spatial resolution and broader spatial coverage allowed more lakes to be included in modeling efforts. GDEM2 was shown to offer superior utility for estimating hs compared to other satellite-derived data, but was limited by its consistent underestimation of hs, inability to detect within-buffer hs variability, and differing accuracy across land cover types. Nonetheless

  17. Visual impact assessment of offshore wind farms and prior experience

    Energy Technology Data Exchange (ETDEWEB)

    Ladenburg, Jacob [Danish Institute of Governmental Research, Nyropsgade 37, 1602 Copenhagen V (Denmark)

    2009-03-15

    Energy planners have shifted their attention towards offshore wind power generation and the decision is supported by the public in general, which in the literature has a positive attitude towards offshore wind generation. However, globally only a few offshore wind farms are operating. As more wind farms start operating and more people become experienced with especially the visual impacts from offshore wind farms, the public positive attitude could change if the experienced impacts are different from the initially perceived visual interference. Using a binary logit model, the present paper investigates the relation between different levels of prior experience with visual disamenities from offshore wind farms and perception of visual impacts from offshore wind farms. The differences in prior experience are systematically controlled for sampling respondents living in the areas close to the large scale offshore wind farms Nysted and Horns Rev and by sampling the a group of respondents representing the Danish population, which has little experience with offshore wind farms. Compared to previous results in the literature, the present paper finds that perception of wind power generation is influenced by prior experience. More specifically, the results show that people with experience from offshore wind farms located far from the coast have a significant more positive perception of the visual impacts from offshore wind farms than people with experience from wind farms located closer to the coast. These results are noteworthy on two levels. First of all, the results show that perceptions of offshore wind generation are systematically significantly influenced by prior experience with offshore wind farms. Secondly, and in a policy context, the results indicate that the future acceptance of future offshore wind farms is not independent of the location of existing and new offshore wind farms. This poses for caution in relation to locating offshore wind farms too close to the

  18. Dynamic Properties of Offshore Wind Turbine Foundations

    DEFF Research Database (Denmark)

    Damgaard, Mads

    , there is a general consensus that offshore wind-generated electricity is still too expensive to be competitive with conventional energy sources. As a consequence, the overall weight of the turbine and foundation is kept to a minimum resulting in a flexible and dynamically active structural system—even at low......Increasing oil prices and energy demands combined with a general acceptance that fossil fuels drive the climate changes justify the development of new sustainable energy solutions. Although offshore wind energy has proven potential to produce reliable quantities of renewable energy...... frequencies. The highly variable and cyclic loads on the rotor, tower and foundation, caused by wind and wave loads as well as low-frequent excitations from the rotor blades, all demand special fatigue design considerations and create an even greater demand for a fuller appreciation of how the wind turbine...

  19. Study on wind turbine arrangement for offshore wind farms

    DEFF Research Database (Denmark)

    Shen, Wen Zhong; Mikkelsen, Robert Flemming

    2011-01-01

    In this paper, the separation distance between two neighboring offshore wind turbines has been carried out by using the Actuator Line/Navier-Stokes technique developed at the Technical University of Denmark (DTU). Under offshore atmospheric conditions, Large Eddy Simulation has been performed...... for two Tjæreborg 2 MW wind turbines in tandem with separation distances of 4D, 5D, 6D, 7D, 8D and 10D at the design wind speed of 10 m/s. The power performance of the wake turbine showed to be about 23% of the first turbine at a separation distance of 4D while its performance reached about 50% at 7D due...... to the turbulence mixing. This study hints that the optimal separation distance between neighboring turbines for offshore wind farms should be 7 rotor diameters....

  20. Offshore Wind Turbines - Estimated Noise from Offshore Wind Turbine, Monhegan Island, Maine: Environmental Effects of Offshore Wind Energy Development

    Energy Technology Data Exchange (ETDEWEB)

    Aker, Pamela M.; Jones, Anthony M.; Copping, Andrea E.

    2010-11-23

    Deep C Wind, a consortium headed by the University of Maine will test the first U.S. offshore wind platforms in 2012. In advance of final siting and permitting of the test turbines off Monhegan Island, residents of the island off Maine require reassurance that the noise levels from the test turbines will not disturb them. Pacific Northwest National Laboratory, at the request of the University of Maine, and with the support of the U.S. Department of Energy Wind Program, modeled the acoustic output of the planned test turbines.

  1. Understanding public responses to offshore wind power

    Energy Technology Data Exchange (ETDEWEB)

    Haggett, Claire [Sociology, School of Social and Political Science, University of Edinburgh, Chrystal MacMillan Building, George Square, Edinburgh, EH8 9LD (United Kingdom)

    2011-02-15

    This paper is about understanding the role and importance of public responses to offshore wind power. It builds on a framework for understanding social acceptance and opposition to onshore turbines, and reviews the emerging research on offshore wind. While less is known about how people will respond to offshore than onshore wind, there is now an emerging body of research. From this literature, several common factors which influence responses have emerged and are discussed here: the (continued) role of visual impact; place attachment to the local area; lack of tangible benefits; relationships with developers and outsiders; and the role of the planning and decision-making systems. The paper argues that, as with onshore developments, the public should be included in decision-making about offshore wind farms, and that they have a key role which should not be underestimated. The paper concludes with some thoughts about the means to involve people and how effected communities might be effectively acknowledged, identified and engaged. (author)

  2. Floating offshore wind turbines for shallow waters

    NARCIS (Netherlands)

    Bulder, B.H.; Henderson, A.; Huijsmans, R.H.M.; Peeringa, J.M.; Pierik, J.T.G.; Snijders, E.J.B.; Hees, M.Th. van; Wijnants, G.H.; Wolf, M.J.

    2003-01-01

    Bottom mounted Offshore wind turbines seem to have a promising future but they are restricted to shallow waters of Northern Europe. Many projects are planned or are in the phase of construction on the North Sea and the Baltic Sea. All projects that are planned have a water depth up to approximately

  3. Wake dynamics in offshore wind farms

    DEFF Research Database (Denmark)

    de Mare, Martin Tobias

    Wind turbines within offshore wind farms spend considerable time operating in the wake of neighboring wind turbines. An important contribution to the loads on a wake-affected wind turbine is the slow movement of the wake from the upstream wind turbine across the rotor of the wake-affected wind...... to be uniquely determined by the friction velocity, the shear and the dissipation of turbulent kinetic energy, all of them physical properties of the flow. If local equilibrium between the turbulent kinetic energy produced by shear and the turbulent kinetic energy dissipated as heat is assumed, then, for neutral...... components of the cross-spectra at known shear, is proposed. Future work could also include investigating if a Rapid Distortion formulation that also includes a term for buoyancy effects is needed in order to make accurate predictions for non-neutral atmospheric stratification....

  4. Innovative Offshore Wind Plant Design Study

    Energy Technology Data Exchange (ETDEWEB)

    Hurley, William L. [Glosten Associates, Inc., Seattle, WA (United States); Nordstrom, Charles J. [Glosten Associates, Inc., Seattle, WA (United States); Morrison, Brent J. [Glosten Associates, Inc., Seattle, WA (United States)

    2013-12-18

    Technological advancements in the Glosten PelaStar floating wind turbine system have led to projected cost of energy (COE) reductions from today’s best-in-class offshore wind systems. The PelaStar system is projected to deliver a COE that is 35% lower than that delivered by the current offshore wind plants. Several technology developments have been achieved that directly target significant cost of energy reductions. These include: Application of state-of-the-art steel construction materials and methods, including fatigue-resistant welding techniques and technologies, to reduce hull steel weight; Advancements in synthetic fiber tendon design for the mooring system, which are made possible by laboratory analysis of full-scale sub-rope specimens; Investigations into selected anchor technologies to improve anchor installation methods; Refinement of the installation method, specifically through development of the PelaStar Support Barge design. Together, these technology developments drive down the capital cost and operating cost of offshore wind plants and enable access to superb wind resources in deep water locations. These technology developments also reduce the uncertainty of the PelaStar system costs, which increases confidence in the projected COE reductions.

  5. The (Revolution of China: Offshore Wind Diffusion

    Directory of Open Access Journals (Sweden)

    Thomas Poulsen

    2017-12-01

    Full Text Available This research presents an industry level gap analysis for Chinese offshore wind, which serves as a way to illuminate how China may fast track industry evolution. The research findings provide insight into how the Chinese government strongly and systematically decrees state-owned Chinese firms to expand into overseas markets to speed up learning efforts. Insights are offered regarding the nation-level strategic plans and institutional support policies mobilized by China in order to be able to conquer market shares internationally by building a strong home market and then facilitating an end-to-end and fully financed export solution. This is interesting in itself and in particular so because it now also includes complex billion-dollar megaprojects such as turnkey offshore wind farm assets with an expected lifespan of 30+ years. Research findings are provided on how European and Chinese firms may successfully forge long-term alliances also for future Chinese wind energy export projects. Examples of past efforts of collaboration not yielding desired results have been included as well. At policy level, recommendations are provided on how the evolution of the Chinese offshore wind power industry can be fast-tracked to mirror the revolutionary pace, volume, and velocity which the Chinese onshore wind power industry has mustered.

  6. IEA Wind Task 26: Offshore Wind Farm Baseline Documentation

    Energy Technology Data Exchange (ETDEWEB)

    Smart, Gavin [Offshore Renewable Energy Catapult, Blyth, Northumberland (United Kingdom); Smith, Aaron [National Renewable Energy Lab. (NREL), Golden, CO (United States); Warner, Ethan [National Renewable Energy Lab. (NREL), Golden, CO (United States); Sperstad, Iver Bakken [SINTEF Energy Research, Trondheim (Norway); Prinsen, Bob [Ecofys, Utrecht (Netherlands). TKI Wind Op Zee; Lacal-Arantegui, Roberto [European Commission Joint Research Centre (JRC), Brussels (Belgium)

    2016-06-02

    This document has been produced to provide the definition and rationale for the Baseline Offshore Wind Farm established within IEA Wind Task 26--Cost of Wind Energy. The Baseline has been developed to provide a common starting point for country comparisons and sensitivity analysis on key offshore wind cost and value drivers. The baseline project reflects an approximate average of the characteristics of projects installed between 2012 and 2014, with the project life assumed to be 20 years. The baseline wind farm is located 40 kilometres (km) from construction and operations and maintenance (O&M) ports and from export cable landfall. The wind farm consists of 100 4-megawatt (MW) wind turbines mounted on monopile foundations in an average water depth of 25 metres (m), connected by 33-kilovolt (kV) inter-array cables. The arrays are connected to a single offshore substation (33kV/220kV) mounted on a jacket foundation, with the substation connected via a single 220kV export cable to an onshore substation, 10km from landfall. The wind farm employs a port-based O&M strategy using crew-transfer vessels.

  7. Visual disamenities from off-shore wind farms in Denmark

    DEFF Research Database (Denmark)

    Ladenburg, Jacob; Dubgaard, Alex; Tranberg, Jesper

    2006-01-01

    Expansion of the off-shore wind power plays a significant role in the energy policies of many EU countries. However, off-shore wind farms create visual disamenities. These disamenities can be reduced by locating wind farms at larger distances from the coast – and accepting higher costs per k......Wh produced. Base on the choices among alternative wind farm outlays, the preferences for reducing visual disamenities of off-shore wind farms were elicited using the Choice Experiment Method. The results show a clear picture; the respondents in three independent samples are willing to pay for mowing future...... off-shore wind farms away from the shore to reduce the wind farms visibility. However, the results also denote that the preferences vary with regards to the experiences with visual disamenities of off-shore wind farms. The respondents Horns Revs sample, where the off-shore wind farm is located...

  8. Power Transmission from Large Offshore Wind Farms

    DEFF Research Database (Denmark)

    Pedersen, Jørgen Kaas

    1999-01-01

    The major part of the coming wind farms in Denmark will be placed offshore. If the location is near a grid with a high short circuit level the power can be transmitted as AC.If the wind farm is far away from the grid and the grid perhaps has a low short circuit level, the best solution for transm......The major part of the coming wind farms in Denmark will be placed offshore. If the location is near a grid with a high short circuit level the power can be transmitted as AC.If the wind farm is far away from the grid and the grid perhaps has a low short circuit level, the best solution...... for transmitting the power can be by DC. At the moment it is possible to build self-commutating DC/AC-inverters up to about 150 kV. This paper will show a concept to a solution for a wind farm and a transmission system based on synchronous generators or a powerformer® with a rated voltage of 50 kV. The AC power...... will be rectified and boosted to a fixed DC voltage (e.g. 100 kV). The speed of the generator will be variable, depending of the wind but also controlled with the duty-cycle of the booster. In that way all wind turbines can be connected to the same DC bus and the cable to the inverter station connected to the AC...

  9. Transient LES of an offshore wind turbine

    Directory of Open Access Journals (Sweden)

    L. Vollmer

    2017-12-01

    Full Text Available The estimation of the cost of energy of offshore wind farms has a high uncertainty, which is partly due to the lacking accuracy of information on wind conditions and wake losses inside of the farm. Wake models that aim to reduce the uncertainty by modeling the wake interaction of turbines for various wind conditions need to be validated with measurement data before they can be considered as a reliable estimator. In this paper a methodology that enables a direct comparison of modeled with measured flow data is evaluated. To create the simulation data, a model chain including a mesoscale model, a large-eddy-simulation (LES model and a wind turbine model is used. Different setups are compared to assess the capability of the method to reproduce the wind conditions at the hub height of current offshore wind turbines. The 2-day-long simulation of the ambient wind conditions and the wake simulation generally show good agreements with data from a met mast and lidar measurements, respectively. Wind fluctuations due to boundary layer turbulence and synoptic-scale motions are resolved with a lower representation of mesoscale fluctuations. Advanced metrics to describe the wake shape and development are derived from simulations and measurements but a quantitative comparison proves to be difficult due to the scarcity and the low sampling rate of the available measurement data. Due to the implementation of changing synoptic wind conditions in the LES, the methodology could also be beneficial for case studies of wind farm performance or wind farm control.

  10. Offshore Wind Energy Cost Modeling Installation and Decommissioning

    CERN Document Server

    Kaiser, Mark J

    2012-01-01

    Offshore wind energy is one of the most promising and fastest growing alternative energy sources in the world. Offshore Wind Energy Cost Modeling provides a methodological framework to assess installation and decommissioning costs, and using examples from the European experience, provides a broad review of existing processes and systems used in the offshore wind industry. Offshore Wind Energy Cost Modeling provides a step-by-step guide to modeling costs over four sections. These sections cover: ·Background and introductory material, ·Installation processes and vessel requirements, ·Installation cost estimation, and ·Decommissioning methods and cost estimation.  This self-contained and detailed treatment of the key principles in offshore wind development is supported throughout by visual aids and data tables. Offshore Wind Energy Cost Modeling is a key resource for anyone interested in the offshore wind industry, particularly those interested in the technical and economic aspects of installation and decom...

  11. Floating offshore wind turbines for shallow waters

    Energy Technology Data Exchange (ETDEWEB)

    Bulder, B.H.; Peeringa, J.M.; Pierik, J.T.G. [ECN Wind Energy, Petten (Netherlands); Henderson, A. [Section Wind Energy, Delft University of Technology, Delft (Netherlands); Huijsmans, R.H.M.; Van Hees, M.Th. [Maritime Research Institute Netherlands, MARIN, Wageningen (Netherlands); Snijders, E.J.B. [Marine Structure Consultants MSC, Schiedam (Netherlands); Wijnants, G.H.; Wolf, M.J. [TNO, Delft (Netherlands)

    2003-06-01

    Bottom mounted Offshore wind turbines seem to have a promising future but they are restricted to shallow waters such as in Northern Europe. Many projects are planned or are in the phase of construction in the North Sea and the Baltic Sea. All projects planned to date are in water depths of up to approximately 25 m. The research project reported in this paper investigated the technical and economical feasibility of floating wind energy systems in deeper waters, of approximately 50 m and deeper. It is assumed that at a certain water depth floating wind turbines will have better economics than bottom mounted wind turbines. Floating wind energy systems seem to have some advantages over bottom mounted wind energy systems, such as: lower cost installation (in a harbour); lower maintenance cost; lower removal cost. But floating wind energy systems have their own technical challenges, such as dynamic interactions between floater and wind turbine; floater conceptual design including mooring system, taking into account restriction w.rt. stability of floater and wind turbine, minimizing wave induced motion, water depth, etc. This paper summarises the activities undertaken within the FloatWind feasibility study carried out during 2001-2002. Full details are to be found in the Final Report, also available from ECN or any of the authors.

  12. National Offshore Wind Strategy: Facilitating the Development of the Offshore Wind Industry in the United States

    Energy Technology Data Exchange (ETDEWEB)

    Gilman, Patrick [National Renewable Energy Lab. (NREL), Golden, CO (United States); Maurer, Ben [National Renewable Energy Lab. (NREL), Golden, CO (United States); Feinberg, Luke [National Renewable Energy Lab. (NREL), Golden, CO (United States); Duerr, Alana [National Renewable Energy Lab. (NREL), Golden, CO (United States); Peterson, Lauren [National Renewable Energy Lab. (NREL), Golden, CO (United States); Musial, Walt [National Renewable Energy Lab. (NREL), Golden, CO (United States); Beiter, Phillipp [National Renewable Energy Lab. (NREL), Golden, CO (United States); Golladay, Jennifer [Dept. of the Interior (DOI), Washington DC (United States); Stromberg, Jessica [Dept. of the Interior (DOI), Washington DC (United States); Johnson, Isis [Dept. of the Interior (DOI), Washington DC (United States); Boren, Doug [Dept. of the Interior (DOI), Washington DC (United States); Moore, Annette [Dept. of the Interior (DOI), Washington DC (United States)

    2016-09-01

    The U.S. Department of Energy, through its Wind Energy Technologies Office, and U.S. Department of the Interior, through its Bureau of Ocean Energy Management, have jointly produced this updated national strategy to facilitate the responsible development of offshore wind energy in the United States.

  13. North Sea Offshore Wind Power Variability in 2020 and 2030

    OpenAIRE

    Nicolaos Antonio CUTULULIS; Litong-Palima, Marisciel; Sørensen, Poul Ejnar

    2012-01-01

    Wind power is currently the most promising renewable technology and is expected to contribute significantly to achieving the “20-20-20” target set by EU - 20% reduction of greenhouse gases and 20% share of renewables by 2020. The development potential of wind power, especially offshore, is huge. The experience with large offshore wind farms so far has clearly shown that the offshore wind power is significantly more variable than the on-shore wind power, first of all because offshore wind powe...

  14. Mapping seabird sensitivity to offshore wind farms.

    Directory of Open Access Journals (Sweden)

    Gareth Bradbury

    Full Text Available We present a Geographic Information System (GIS tool, SeaMaST (Seabird Mapping and Sensitivity Tool, to provide evidence on the use of sea areas by seabirds and inshore waterbirds in English territorial waters, mapping their relative sensitivity to offshore wind farms. SeaMaST is a freely available evidence source for use by all connected to the offshore wind industry and will assist statutory agencies in assessing potential risks to seabird populations from planned developments. Data were compiled from offshore boat and aerial observer surveys spanning the period 1979-2012. The data were analysed using distance analysis and Density Surface Modelling to produce predicted bird densities across a grid covering English territorial waters at a resolution of 3 km×3 km. Coefficients of Variation were estimated for each grid cell density, as an indication of confidence in predictions. Offshore wind farm sensitivity scores were compiled for seabird species using English territorial waters. The comparative risks to each species of collision with turbines and displacement from operational turbines were reviewed and scored separately, and the scores were multiplied by the bird density estimates to produce relative sensitivity maps. The sensitivity maps reflected well the amassed distributions of the most sensitive species. SeaMaST is an important new tool for assessing potential impacts on seabird populations from offshore development at a time when multiple large areas of development are proposed which overlap with many seabird species' ranges. It will inform marine spatial planning as well as identifying priority areas of sea usage by marine birds. Example SeaMaST outputs are presented.

  15. Mapping seabird sensitivity to offshore wind farms.

    Science.gov (United States)

    Bradbury, Gareth; Trinder, Mark; Furness, Bob; Banks, Alex N; Caldow, Richard W G; Hume, Duncan

    2014-01-01

    We present a Geographic Information System (GIS) tool, SeaMaST (Seabird Mapping and Sensitivity Tool), to provide evidence on the use of sea areas by seabirds and inshore waterbirds in English territorial waters, mapping their relative sensitivity to offshore wind farms. SeaMaST is a freely available evidence source for use by all connected to the offshore wind industry and will assist statutory agencies in assessing potential risks to seabird populations from planned developments. Data were compiled from offshore boat and aerial observer surveys spanning the period 1979-2012. The data were analysed using distance analysis and Density Surface Modelling to produce predicted bird densities across a grid covering English territorial waters at a resolution of 3 km×3 km. Coefficients of Variation were estimated for each grid cell density, as an indication of confidence in predictions. Offshore wind farm sensitivity scores were compiled for seabird species using English territorial waters. The comparative risks to each species of collision with turbines and displacement from operational turbines were reviewed and scored separately, and the scores were multiplied by the bird density estimates to produce relative sensitivity maps. The sensitivity maps reflected well the amassed distributions of the most sensitive species. SeaMaST is an important new tool for assessing potential impacts on seabird populations from offshore development at a time when multiple large areas of development are proposed which overlap with many seabird species' ranges. It will inform marine spatial planning as well as identifying priority areas of sea usage by marine birds. Example SeaMaST outputs are presented.

  16. Water-hydraulic power transmission for offshore wind farms

    NARCIS (Netherlands)

    Diepeveen, N.F.B.; Jarquin Laguna, A.; Kempenaar, A.S.

    2012-01-01

    The current state of the art of offshore wind turbine power transmission technology is expensive, heavy and maintenance intensive. The Delft Offshore Turbine project considers a radically new concept for power transmission in an offshore wind farm: using seawater as power transmission medium. For

  17. Interconnector capacity allocation in offshore grids with variable wind generation

    DEFF Research Database (Denmark)

    Schröder, Sascha Thorsten

    2013-01-01

    the interconnector capacity should be allocated for wind generation and for international power trading. The main difficulty arises from the stochastic nature of wind generation: in a case with radial connections to the national coast, the wind park owner has the possibility of aggregating the offshore wind park......Different capacity allocation regimes have a strong impact on the economics of offshore wind farms and on interconnectors in offshore grids. Integrating offshore generation in offshore grids is currently a subject of discussion for different regions, e.g. the North Sea. A novel question is how....... It is concluded that treating offshore generation as a single price zone within the interconnector reduces the wind operator’s ability to pool it with other generation. Furthermore, a single offshore price zone between two markets will always receive the lower spot market price of the neighbouring zones, although...

  18. Integrated installation for offshore wind turbines

    Energy Technology Data Exchange (ETDEWEB)

    Way, J.; Bowerman, H.

    2003-07-01

    A project to investigate the feasibility of integrating the offshore installation of foundation, turbine and tower for offshore wind turbines into one operation is described. Three separate objectives are listed. They are: (1) Telescopic tower study - reversible process incorporating lift and lock mechanisms; (2) Transportation study - technical and economic feasibility of transporting and installing a wind turbine unit via a standard barge with minimal conversion and (3) Self-burial system study - to demonstrate the feasibility of self burial of a slab foundation via controlled jetting beneath the slab. The background to the study and the proposed concepts are discussed. The work carried out to date and the costs are reported together with the findings. Recommendations for future work are listed. The work was carried out by Corus UK Ltd and is managed by Future Energy Solutions for the DTI.

  19. Scour Forecasting for Offshore Wind Parks

    DEFF Research Database (Denmark)

    Hartvig, Peres Akrawi

    , scour forecasts facilitate the comparison between a scour design based on either deployment of scour-protection or enhanced structural design. The broad goal is to develop a method that produces accurate scour forecasts for offshore wind parks. The present research investigates more specifically which......In an effort to minimize the costs of offshore wind parks, the present research deals with optimizing a certain aspect of the support structure, namely the approach to scour. Scour is the phenomenon of seabed changes in the vicinity of the support structure that arises when the support structure...... of the support and super structure. In case of waves, however, the flow disturbance can be much weaker and even backfill the hole with soil. The ability to accurately forecast this development of the geometry of the scour hole becomes central for obtaining both a safe and cost-effective solution. In practice...

  20. Using Sentinel-1 SAR satellites to map wind speed variation across offshore wind farm clusters

    Science.gov (United States)

    James, S. F.

    2017-11-01

    Offshore wind speed maps at 500m resolution are derived from freely available satellite Synthetic Aperture Radar (SAR) data. The method for processing many SAR images to derive wind speed maps is described in full. The results are tested against coincident offshore mast data. Example wind speed maps for the UK Thames Estuary offshore wind farm cluster are presented.

  1. Satellite winds as a tool for offshore wind resource assessment: The Great Lakes Wind Atlas

    DEFF Research Database (Denmark)

    Doubrawa, Paula; Barthelmie, Rebecca Jane; Pryor, Sara C.

    2015-01-01

    This work presents a new observational wind atlas for the Great Lakes, and proposes a methodology to combine in situ and satellite wind observations for offshore wind resource assessment. Efficient wind energy projects rely on accurate wind resource estimates, which are complex to obtain offshore...... the North American Regional Reanalysis. Generalized wind climates are obtained for each buoy and coastal site with the wind model WAsP, and combined into a single wind speed estimate for the Great Lakes region. The method of classes is used to account for the temporal sparseness in the SAR data set...

  2. Kickoff of offshore wind power in China: playoffs for China wind power development

    OpenAIRE

    Xiliang, Zhang; Da, Zhang; Stua, Michele

    2012-01-01

    Year 2010 is the significant year of offshore wind power development in China. The first national offshore wind power project is connected to the grid, and the first round of concession projects marks the strong support from central government. It is foreseeable that offshore wind power capacity in China will expand rapidly in the future, and the understanding pattern of it is crucial for analyzing the overall wind market in China and global offshore wind power development. This paper firstly...

  3. North Sea Offshore Wind Power Variability in 2020 and 2030

    DEFF Research Database (Denmark)

    Cutululis, Nicolaos Antonio; Litong-Palima, Marisciel; Sørensen, Poul Ejnar

    2012-01-01

    Wind power is currently the most promising renewable technology and is expected to contribute significantly to achieving the “20-20-20” target set by EU - 20% reduction of greenhouse gases and 20% share of renewables by 2020. The development potential of wind power, especially offshore, is huge....... The experience with large offshore wind farms so far has clearly shown that the offshore wind power is significantly more variable than the on-shore wind power, first of all because offshore wind power is more concentrated geographically than existing on-shore wind power. The focus is on time scales of interest...... for power system operation, thus ranging from minutes to hours. The simulations are based on the offshore wind power development plans developed in the TWENTIES project and includes details such as installed capacity and coordinates for each wind farm existing or planned to be installed in North Europe...

  4. A methodology for the prediction of offshore wind energy resources

    Energy Technology Data Exchange (ETDEWEB)

    Watson, S.J.; Watson, G.M. [Rutherford Appleton Lab., Oxfordshire (United Kingdom); Holt, R.J. [Univ. of East Anglia, Climatic Research Unit, Norwich (United Kingdom)] Barthelmie, R.J. [Risoe National Lab., Dept. of Wind Energy and Atmospheric Physics, Roskilde (Denmark); Zuylen, E.J. van [Ecofys Energy and Environment, Utrecht (Netherlands)] Cleijne, J.W. [Kema Sustainable, Arnhem (Netherlands)

    1999-03-01

    There are increasing constraints on the development of wind power on land. Recently, there has been a move to develop wind power offshore, though the amount of measured wind speed data at potential offshore wind farm sites is sparse. We present a novel methodology for the prediction of offshore wind power resources which is being applied to European Union waters. The first stage is to calculate the geostrophic wind from long-term pressure fields over the sea area of interest. Secondly, the geostrophic wind is transformed to the sea level using WA{sup s}P, taking account of near shore topography. Finally, these values are corrected for land/sea climatology (stability) effects using an analytical Coastal discontinuity Model (CDM). These values are further refined using high resolution offshore data at selected sites. The final values are validated against existing offshore datasets. Preliminary results are presented of the geostrophic wind speed validation in European Union waters. (au)

  5. Integration of Wave and Offshore Wind Energy in a European Offshore Grid

    DEFF Research Database (Denmark)

    Chozas, Julia Fernandez; Sørensen, H. C.; Korpås, M.

    2010-01-01

    High wave and offshore wind energy potentials are located along the West and North coasts of Europe, respectively. In the near future, these resources should significantly contribute to the European electricity mix, but there is hardly any grid infrastructure available for large scale integration...... of offshore renewable energy sources. According to this, the paper covers i) public and private initiatives for offshore transmission networks, ii) the synergies between the wave and the offshore wind energy sector within an offshore grid, iii) power transmission options for offshore generation and iv...

  6. 2016 Offshore Wind Energy Resource Assessment for the United States

    Energy Technology Data Exchange (ETDEWEB)

    Musial, Walt [National Renewable Energy Lab. (NREL), Golden, CO (United States); Heimiller, Donna [National Renewable Energy Lab. (NREL), Golden, CO (United States); Beiter, Philipp [National Renewable Energy Lab. (NREL), Golden, CO (United States); Scott, George [National Renewable Energy Lab. (NREL), Golden, CO (United States); Draxl, Caroline [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2016-09-01

    This report, the 2016 Offshore Wind Energy Resource Assessment for the United States, was developed by the National Renewable Energy Laboratory, and updates a previous national resource assessment study, and refines and reaffirms that the available wind resource is sufficient for offshore wind to be a large-scale contributor to the nation's electric energy supply.

  7. Offshore Wind Farm Clusters - Towards new integrated Design Tool

    DEFF Research Database (Denmark)

    Hasager, Charlotte Bay; Réthoré, Pierre-Elouan; Peña, Alfredo

    In EERA DTOC testing of existing wind farm wake models against four validation data test sets from large offshore wind farms is carried out. This includes Horns Rev-1 in the North Sea, Lillgrund in the Baltic Sea, Roedsand-2 in the Baltic Sea and from 10 large offshore wind farms in Northern...

  8. Cable route optimization for offshore wind farms in morphodynamic areas

    NARCIS (Netherlands)

    Roetert, T.J.; Raaijmakers, T.; Borsje, Bastiaan Wijnand

    2017-01-01

    The aim of this paper is to optimize power cable routing in a wind farm based on the expected morphological behaviour in the design lifetime of an offshore wind farm. Up to now methods to optimize cable route layout in offshore wind farms are only based on a flat seabed and do not take the seabed

  9. Offshore Code Comparison Collaboration (OC3) for IEA Wind Task 23 Offshore Wind Technology and Deployment

    Energy Technology Data Exchange (ETDEWEB)

    Jonkman, J.; Musial, W.

    2010-12-01

    This final report for IEA Wind Task 23, Offshore Wind Energy Technology and Deployment, is made up of two separate reports, Subtask 1: Experience with Critical Deployment Issues and Subtask 2: Offshore Code Comparison Collaborative (OC3). Subtask 1 discusses ecological issues and regulation, electrical system integration, external conditions, and key conclusions for Subtask 1. Subtask 2 included here, is the larger of the two volumes and contains five chapters that cover background information and objectives of Subtask 2 and results from each of the four phases of the project.

  10. Offshore wind energy. An overview on the activities in Germany; Offshore-Windenergie. Ein Ueberblick ueber die Aktivitaeten in Deutschland

    Energy Technology Data Exchange (ETDEWEB)

    Worm, Anja [media consulta Deutschland GmbH, Berlin (Germany)

    2013-02-15

    The brochure under consideration provides an overview of the activities of offshore wind energy in Germany. The first offshore wind farms are built and generate more electricity than expected. The offshore wind farms serve as a field of learning for new technologies. The power of offshore wind farms opened new prospects for the economy. The northern Federal States of Germany as well as the traditional locations for mechanical engineering and steel production benefit from offshore wind energy.

  11. Environmental issues of offshore wind farms

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2002-07-01

    Placing wind farms offshore eliminates some of the obstacles encountered when siting wind farms on shore like visual influence on the landscape, annoyance to inhabitants from noise and flickering light, conflicts with other planning interests etc. Other challenges remain - like influence on birds - and new are added like influence on marine life, hydrography and marine traffic. While there are now 20 years of experience in assessing and meeting environmental challenges associated with land based wind installations little is known of the effects of offshore wind installations. The planning and approval procedure for each offshore wind farm installed so far has been on a case-by-case basis as have the demands for environmental surveys prior to installation and monitoring programs during construction and operation. The meeting gathered 24 people from five different countries. Participants came from government agencies, energy agencies (or suppliers) universities and research institutes (both ecological and technical). The aim of the meeting was to make an inventory of the already existing and available information on environmental aspects of offshore wind energy. Another aim was to give recommendations to the COD-project (Concerted action for Offshore wind energy Deployment) on how to proceed within the work package regarding: Collection of information on activities (projects) of participating countries, including at least birds, benthic flora and fauna, sub-sea noise, visual intrusion, and coastal impacts. The meeting mainly focused on: National programs to enforce offshore wind energy; Studies and experiences of influence on birds and sea mammals; Experience and application of Environmental Impact Assessment. One outcome of the COD-project will be a database of environmental issues. At the end of the meeting it was discussed, what kind of information this database should contain: 1. Base line data; 2. Methods for investigating biological data; 3. Methods for the

  12. System Reliability for Offshore Wind Turbines

    DEFF Research Database (Denmark)

    Marquez-Dominguez, Sergio; Sørensen, John Dalsgaard

    2013-01-01

    E). In consequence, a rational treatment of uncertainties is done in order to assess the reliability of critical details in OWTs. Limit state equations are formulated for fatigue critical details which are not influenced by wake effects generated in offshore wind farms. Furthermore, typical bi-linear S-N curves...... are considered for reliability verification according to international design standards of OWTs. System effects become important for each substructure with many potential fatigue hot spots. Therefore, in this paper a framework for system effects is presented. This information can be e.g. no detection of cracks...

  13. Fluctuations of offshore wind generation: Statistical modelling

    DEFF Research Database (Denmark)

    Pinson, Pierre; Christensen, Lasse E.A.; Madsen, Henrik

    2007-01-01

    ) and Markov-Switching AutoRegressive (MSAR) models are considered. The particularities of these models are presented, as well as methods for the estimation of their parameters. Simulation results are given for the case of the Horns Rev and Nysted offshore wind farms in Denmark, for time-series of power...... production averaged at a 1, 5, and 10-minute rate. The exercise consists in one-step ahead forecasting of these time-series with the various regime-switching models. It is shown that the MSAR model, for which the succession of regimes is represented by a hidden Markov chain, significantly outperforms...

  14. Offshore system for integration of the wind energy; Sistema offshore para integracao de energia eolica

    Energy Technology Data Exchange (ETDEWEB)

    Decker, Jan de [3E, Brussels (Belgium); Tambke, Jens [Universidade de Oldemburg (Germany). ForWind; Voelker, J. [Dena - Agencia Alema de Energia (Germany); Michalowska-Knap, Katarzyna [Instituto de Energia Renovavel (Poland)

    2010-09-15

    The Offshore Grid project aims to analyze the conditions required for the development of an offshore transmission network to integrate renewable energy (wind) to the national electrical systems, securely and efficiently. Regulatory aspects, technical, economic and political are considered, that will help the various players in the industry to have a common view on the offshore power grids in Europe.

  15. New Models for Maintenance of Offshore Wind Farms

    DEFF Research Database (Denmark)

    Petersen, Kristian R.

    Operations and maintenance (O&M) processes are important for keeping offshore wind turbines in operation. Costs related to such activities constitute approximately 30% of the lifetime cost of an offshore wind farm project. Currently, the offshore wind energy industry has shown a rapid increase....... First, how lean can be instituted in an offshore wind farm was investigated. The research included investigations of how lean has contributed to the reduction of scheduled maintenance time as well as the increase of wind turbine availability. Based on field studies, seven types of O&M wastes related...... to offshore wind turbines were defined, from which findings from the case study on lean were analysed. In this analysis it is identified that Modularisation involving maintenance resources and tasks can be used to streamline operations and maintenance processes further. For the medium-term tactical...

  16. Different Transportation and Maintenance Strategies for Offshore Wind Farms

    DEFF Research Database (Denmark)

    Ambühl, Simon; Sørensen, John Dalsgaard

    Inspections as well as transportation of personnel and repair parts are a significant contributor to the levelized cost of energy for offshore wind turbines. There are different operation and maintenance (O&M) strategies for offshore wind turbines. Maintenance can be performed preventively...... by replacing the component before it breaks down or correctively by replacing it after it failed. A boat or helicopter can be used for transporting personnel and equipment from shore to the wind turbine. This article compares, among others, a risk-based inspection and maintenance approach for an offshore wind...... turbine farm with other O&M approaches where only boats are used to access the offshore wind turbines or where the downtime of the devices are minimized. This article presents a dynamic approach for total operation and maintenance cost estimations of offshore wind turbine farms including real weather data...

  17. NREL Software Aids Offshore Wind Turbine Designs (Fact Sheet)

    Energy Technology Data Exchange (ETDEWEB)

    2013-10-01

    NREL researchers are supporting offshore wind power development with computer models that allow detailed analyses of both fixed and floating offshore wind turbines. While existing computer-aided engineering (CAE) models can simulate the conditions and stresses that a land-based wind turbine experiences over its lifetime, offshore turbines require the additional considerations of variations in water depth, soil type, and wind and wave severity, which also necessitate the use of a variety of support-structure types. NREL's core wind CAE tool, FAST, models the additional effects of incident waves, sea currents, and the foundation dynamics of the support structures.

  18. Offshore wind farm electrical cable layout optimization

    Science.gov (United States)

    Pillai, A. C.; Chick, J.; Johanning, L.; Khorasanchi, M.; de Laleu, V.

    2015-12-01

    This article explores an automated approach for the efficient placement of substations and the design of an inter-array electrical collection network for an offshore wind farm through the minimization of the cost. To accomplish this, the problem is represented as a number of sub-problems that are solved in series using a combination of heuristic algorithms. The overall problem is first solved by clustering the turbines to generate valid substation positions. From this, a navigational mesh pathfinding algorithm based on Delaunay triangulation is applied to identify valid cable paths, which are then used in a mixed-integer linear programming problem to solve for a constrained capacitated minimum spanning tree considering all realistic constraints. The final tree that is produced represents the solution to the inter-array cable problem. This method is applied to a planned wind farm to illustrate the suitability of the approach and the resulting layout that is generated.

  19. Structural Robustness Evaluation of Offshore Wind Turbines

    DEFF Research Database (Denmark)

    Giuliani, Luisa; Bontempi, Franco

    2010-01-01

    Wind turbines are complex structures that should deal with adverse weather conditions, are exposed to impacts or ship collisions and, due to the strategic roles in the energetic supplying, can be the goal of military or malevolent attacks. Even if a structure cannot be design to resist any...... in the framework of a safe design: it depends on different factors, like exposure, vulnerability and robustness. Particularly, the requirement of structural vulnerability and robustness are discussed in this paper and a numerical application is presented, in order to evaluate the effects of a ship collision...... on the structural system of an offshore wind turbine. The investigation resorts nonlinear dynamic analyses performed on the finite element model of the turbine and considers three different scenarios for the ship collision. The review of the investigation results allows for an evaluation of the turbine structural...

  20. The wind speed profile at offshore wind farm sites

    Science.gov (United States)

    Lange, B.; Larsen, S. E.; Højstrup, J.; Barthelmie, R.

    2003-04-01

    The first large offshore wind farms are in the planning phase in several countries in Europe. Their economic viability depends on the favourable wind conditions compared to sites on land. The higher energy yield has to compensate the additional installation and maintenance cost. For project planning and siting a reliable prediction of the wind resource is therefore crucial. For turbine design the wind shear of the marine surface layer is an important design parameter, especially since the growing rotor diameter makes turbines more vulnerable for spatial wind speed variations. Compared to land surfaces the roughness of water is very low. It is commonly described either as a constant (as in the wind resource estimation program WAsP) or by means of the Charnock approach, relating sea surface roughness and friction velocity. While this relation works well for the open oceans it has been found inappropriate for coastal areas where waves are not fully developed. Information about the wave field is needed to model the sea surface roughness more accurately (see e.g. Johnson et al. (1998)). The atmospheric stability differs greatly between land and water areas. It is more important offshore compared to land sites due to the low surface roughness of water. The main influence of the atmospheric stability is on the vertical momentum transport, which is reflected in the vertical wind speed profile. It is usually described with Monin-Obukhov similarity theory. However, other effects not described by this approach might also play an important role: For offshore flow the flow regime at coastal sites is affected by the land-sea discontinuity (Højstrup, 1999). An internal boundary layer develops at the coastline and an inhomogeneous flow field might develop in the coastal zone, especially in stable stratification (see e.g. (Smedman et al. (1997)) Recent data from the measurement at Rødsand, 10 km off the Danish coast in the Baltic Sea, include simultaneous wind and wave data from

  1. Offshore Wind Power Production in Critical Weather Conditions

    OpenAIRE

    Cutululis, Nicolaos Antonio; Litong-Palima, Marisciel; Sørensen, Poul Ejnar

    2012-01-01

    Critical weather conditions, i.e. extreme winds will raise a lot of challenges when it comes to the secure operation of the whole European electric system with the future large scale offshore wind power. This is especially true for Denmark where the target is that wind power should provide 50% of the electricity consumption by 2020. In the EU funded project TWENTIES, the demonstration #4 STORM MANAGEMENT aims at demonstrating that adequate coordination mechanisms between offshore wind farms a...

  2. Overall Optimization for Offshore Wind Farm Electrical System

    DEFF Research Database (Denmark)

    Hou, Peng; Hu, Weihao; Chen, Cong

    2017-01-01

    Based on particle swarm optimization (PSO), an optimization platform for offshore wind farm electrical system (OWFES) is proposed in this paper, where the main components of an offshore wind farm and key technical constraints are considered as input parameters. The offshore wind farm electrical...... system is optimized in accordance with initial investment by considering three aspects: the number and siting of offshore substations (OS), the cable connection layout of both collection system (CS) and transmission system (TS) as well as the selection of electrical components in terms of voltage level...

  3. Quantifying the hurricane catastrophe risk to offshore wind power.

    Science.gov (United States)

    Rose, Stephen; Jaramillo, Paulina; Small, Mitchell J; Apt, Jay

    2013-12-01

    The U.S. Department of Energy has estimated that over 50 GW of offshore wind power will be required for the United States to generate 20% of its electricity from wind. Developers are actively planning offshore wind farms along the U.S. Atlantic and Gulf coasts and several leases have been signed for offshore sites. These planned projects are in areas that are sometimes struck by hurricanes. We present a method to estimate the catastrophe risk to offshore wind power using simulated hurricanes. Using this method, we estimate the fraction of offshore wind power simultaneously offline and the cumulative damage in a region. In Texas, the most vulnerable region we studied, 10% of offshore wind power could be offline simultaneously because of hurricane damage with a 100-year return period and 6% could be destroyed in any 10-year period. We also estimate the risks to single wind farms in four representative locations; we find the risks are significant but lower than those estimated in previously published results. Much of the hurricane risk to offshore wind turbines can be mitigated by designing turbines for higher maximum wind speeds, ensuring that turbine nacelles can turn quickly to track the wind direction even when grid power is lost, and building in areas with lower risk. © 2013 Society for Risk Analysis.

  4. Indian offshore wind energy policy - lessons from Europe

    Energy Technology Data Exchange (ETDEWEB)

    Mani, S.; Dhingra, T. [Univ. of Petroleum and Energy Studies (UPES), Dehradun (India)

    2012-07-01

    Indian Economy is growing at 8% for the past few years and is expected to continue this momentum into the foreseeable future. To sustain this growth, power sector needs to build additional generation capacity at an unprecedented pace. However, continued dependence on fossil fuels (especially Coal and Oil) to power the growth of electricity generation capacity, is hardly sustainable in the long run. The reasons are well known - Environmental concerns, depleting fossil fuel resources, excessive dependency on Oil imports - that it hardly merits repetition. Renewable Energy source forms a miniscule portion (25 GW, {approx} 12%) of India's overall Energy consumption today (202 GW). The share of wind energy (17 GW) is 67% of the total renewable energy basket. But the contribution from offshore wind farms is non-existent, as all the wind energy generated in India is only through onshore Wind farms. India needs a policy framework to encourage the development of offshore wind farms. Several European countries, most notably the UK, Germany and Denmark, have effective offshore wind energy policies that have helped them to accelerate the growth of their offshore wind energy sector. This paper does an exhaustive study to identify the building blocks of a successful offshore wind energy policy initiative adopted by selected European countries, which can be leveraged by India to articulate its own offshore wind energy policy. This paper also suggests a model to predict the log-odds of growth of offshore wind energy sector in India. (Author)

  5. Assessment of the sustainable offshore wind potential in Portugal

    OpenAIRE

    Costa, P; Simões, T.; Estanqueiro, Ana

    2006-01-01

    The sustainable offshore wind potential for the west and south coasts of Portugal is presented. Results were carried out using an atmospheric mesoscale model and GIS tools. Unlike previous common opinions, the preliminary results show the existence of interesting areas for the developing of offshore wind parks.

  6. 2014-2015 Offshore Wind Technologies Market Report

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Aaron

    2015-11-18

    This presentation provides an overview of progress toward offshore wind cost reduction in Europe and implications for the U.S. market. The presentation covers an overview of offshore wind developments, economic and performance trends, empirical evidence of LCOE reduction, and challenges and opportunities in the U.S. market.

  7. A review of the European offshore wind innovation system

    NARCIS (Netherlands)

    Wieczorek, A.J.; Negro, S.O.; Harmsen, R.; Heimeriks, G.J.; Luo, L.; Hekkert, M.P.

    2013-01-01

    Offshore wind has the potential of becoming an important pillar of the future European energy system. It can contribute to policy objectives on climate change, energy security, green growth and social progress. However, the large potential of offshore wind does not automatically lead to a large

  8. A Review of the Western European Offshore Wind Innovation System

    NARCIS (Netherlands)

    Wieczorek, A.J.; Negro, S.O.; Harmsen, R.; Heimeriks, G.J.; Hekkert, M.P.

    2013-01-01

    Offshore wind has the potential of becoming an important pillar of the future European energy system. It can contribute to policy objectives on climate change, energy security, green growth and social progress. However, the large potential of offshore wind does not automatically lead to a large

  9. Unravelling historical cost developments of offshore wind energy in Europe

    NARCIS (Netherlands)

    Voormolen, J. A.; Junginger, H. M.; van Sark, W. G J H M

    2016-01-01

    This paper aims to provide insights in the cost developments of offshore wind energy in Europe. This is done by analysing 46 operational offshore wind farms commissioned after 2000. An increase of the Capital Expenditures (CAPEX) is found that is linked to the distance to shore and depth of more

  10. Fuga - a fast flow model for offshore wind farms

    DEFF Research Database (Denmark)

    Ott, Søren

    2014-01-01

    The Fuga is a fast, yet surprisingly accurate tool that estimates wake losses in offshore wind farms. The Fuga model will be made commercially available in 2014.......The Fuga is a fast, yet surprisingly accurate tool that estimates wake losses in offshore wind farms. The Fuga model will be made commercially available in 2014....

  11. Analysis of North Sea Offshore Wind Power Variability

    NARCIS (Netherlands)

    Buatois, A.; Gibescu, M.; Rawn, B.G.; Van der Meijden, M.A.M.M.

    2014-01-01

    This paper evaluates, for a 2030 scenario, the impact on onshore power systems in terms of the variability of the power generated by 81 GW of offshore wind farms installed in the North Sea. Meso-scale reanalysis data are used as input for computing the hourly power production for offshore wind

  12. Comparison of SAR Wind Speed Retrieval Algorithms for Evaluating Offshore Wind Energy Resources

    DEFF Research Database (Denmark)

    Kozai, K.; Ohsawa, T.; Takeyama, Y.

    2010-01-01

    Envisat/ASAR-derived offshore wind speeds and energy densities based on 4 different SAR wind speed retrieval algorithms (CMOD4, CMOD-IFR2, CMOD5, CMOD5.N) are compared with observed wind speeds and energy densities for evaluating offshore wind energy resources. CMOD4 ignores effects of atmospheric...

  13. EU-NORSEWIND - Delivering Offshore Wind Speed Data

    DEFF Research Database (Denmark)

    Oldroyd, Andy; Hasager, Charlotte Bay; Stickland, M.T.

    and satellite based observations to compile a large and novel wind speed dataset suitable for use in the wind industry. The data will also feed into key areas such as forecasting and MESOSCALE modelling improvements. The result is a large database accessible via a web based interface utilising GIS...

  14. Benchmarking of Wind Turbine Wake Models in Large Offshore Windfarms

    DEFF Research Database (Denmark)

    Gaumond, M.; Réthoré, Pierre-Elouan; Bechmann, Andreas

    Quantifying accurately wind turbine wakes is a key aspect of wind farm economics in large wind farms. This research compares three engineering wake models with power production data from the Horns Rev and Lillgrund offshore wind farms. Single and multiple wake cases are investigated to verify...

  15. Using the PROSA Method in Offshore Wind Farm Location Problems

    OpenAIRE

    Paweł Ziemba; Jarosław Wątróbski; Magdalena Zioło; Artur Karczmarczyk

    2017-01-01

    Wind is the most used renewable energy source (RES) in the European Union and Poland. Due to the legal changes in the scope of RES in Poland, there are plans to develop offshore wind farms at the expense of onshore ones. On the other hand, the success of an offshore wind farm is primarily determined by its location. Therefore, the aim of this study is to select offshore wind farm locations in Poland, based on sustainability assessment, which is an inherent aspect of RES decision-making issues...

  16. POSSPOW: Possible Power of Offshore Wind Power Plants

    DEFF Research Database (Denmark)

    Giebel, Gregor; Göçmen, Tuhfe; Sørensen, Poul Ejnar

    2013-01-01

    Introduction In recent years, the very large offshore wind farms were designed as wind power plants, including possibilities to contribute to the stability of the grid by offering grid services (also called ancillary services). One of those services is reserve power, which is achieved by down......-regulating the wind farm from its maximum possible power. The power can be ramped up quite quickly, but the influence of wakes makes it difficult to assess the exact amount of down-regulation available to sell. Currently, Transmission System Operators (TSOs) have no real way to determine exactly the possible power...... will be verified on some of the large offshore wind farms owned by Vattenfall, and possibly in a DONG Energy wind farm too. Dedicated experiments to the wind flow in large offshore wind farms are planned. Main body of abstract Modern wind turbines have a SCADA signal called possible power. In normal operation...

  17. Aspects of relevance in offshore wind farm reliability assessment

    DEFF Research Database (Denmark)

    Barberis Negra, N.; Holmstrøm, O.; Bak-Jensen, Birgitte

    2007-01-01

    The worldwide increase of installed wind power capacity demands the inclusion of wind farm (WF) models into power system reliability assessment. This paper looks at this issue from available literature, and presenys a list of factors that highly influence offshore WF generation. An example...... of sequential Monte Carlo simulation applied to an offshore WF is described using a new synthetic wind-speed generator. The simulation includes some of the reliability factors highlighted in the paper and their influence on reliability assessment....

  18. An offshore wind atlas for the Canary Islands

    Energy Technology Data Exchange (ETDEWEB)

    Martin Mederos, A.C. [Zona Eolica Canaria S.A., Veintinueve de Abril, 30, Las Palmas 35007 (Spain); Medina Padron, J.F. [Departamento de Ingenieria Electrica, Universidad de Las Palmas de Gran Canaria, 35017 Las Palmas (Spain); Feijoo Lorenzo, A.E. [Departamento de Enxeneria Electrica, Universidade de Vigo, ETSEI, Campus de Lagoas-Marcosende, 36310 Vigo (Spain)

    2011-01-15

    In this paper an analysis of the offshore wind potential in the Canary Islands is presented in the shape of a set of wind maps which constitute an offshore wind atlas. It has been drawn up using data processed from 40 weather stations and satellite. Results from satellite mapping, limited area modelling and mesoscalar modelling have been used by applying the technique known as 'one way nesting'. (author)

  19. Scour protection around offshore wind turbines. Monopiles

    DEFF Research Database (Denmark)

    Nielsen, Anders Wedel; Sumer, B. Mutlu; Fredsøe, Jørgen

    2010-01-01

    The flow processes in a scour protection around a mono-pile in steady current is described in relation to transport of sediment in the scour protection based on physical model tests. Transport of sediment in the scour protection may cause sinking of the scour protection. TYhis may reduce...... the stability of the mono-pile and change for instance the natural frequency of the dynamic response odf an offshore wind turbine in an unfacorable manner. The most importans flow process with regard to transport of sediment and sinking of the scour protection in found to be the horseshoe vortex. It is found...... that a larger pile diameter relative to the size of the protection stones will cause a larger sinking and that two layers of stones will descrease the sinking relative to one layer of stones with the same size....

  20. Concerted action for offshore wind energy deployment (COD). Overview of Environmental Impacts of Offshore Wind energy

    Energy Technology Data Exchange (ETDEWEB)

    Roth, E.M.; Verhoef, L.A.; Dingenouts, M.W.L.

    2004-09-01

    This report is the result of an analysis of all publications on the environmental impacts of offshore wind parks, which have been collected and inserted into a database by the members of the COD working group. The purpose of the overview is to unveil and compare the already available body of reports on Environmental Research of offshore wind energy in a structured way. In this overview the following questions will be addressed: which studies have been published until now? (Chapter 2); what baseline studies were carried out and what methodologies have been studied? (Chapter 3); what are the impacts of Offshore Wind Farms? (Chapter 4); what can be concluded from the reports in the database (Chapter 5); what recommendations are possible up to now? (Chapter 6). Chapter 5 contains recommendations for the environmental research method to be used to obtain the most unequivocal results, the need-to-know information for baseline and effect studies for a good Environmental Impact Assessment and which environmental issues should be studied on a European rather than national.

  1. Offshore wind power economics : analysis on the economic utilization of Turkey's offshore wind power potential under the current support mechanisms

    OpenAIRE

    Ünlü, Mehmet Ali

    2012-01-01

    Climate change and the energy supply security concerns supported the development of wind power growth in the world, which made wind power as one of the fastest growing renewable energy sources. Offshore wind energy attracts more investments day by day with its advantages such as higher wind speeds, larger wind turbines and lower GHG emissions. In order for developing projects that will power the grids with renewable electricity extracted from wind, governments provide extensive policy support...

  2. Optimal Risk-Based Inspection Planning for Offshore Wind Turbines

    DEFF Research Database (Denmark)

    Rangel-Ramirez, Jose G.; Sørensen, John Dalsgaard

    2008-01-01

    , inspection and maintenance activities are developed. This paper considers aspects of inspection and maintenance planning of fatigue prone details in jacket and tripod types of wind turbine support structures. Based oil risk-based inspection planning methods used for oil & gas installations, a framework......Wind turbines for electricity production have increased significantly the last years both in production capability and size. This development is expected to continue also in the coining years. The Support structure for offshore wind turbines is typically a steel structure consisting of a tower...... for optimal inspection and maintenance planning of offshore wind turbines is presented. Special aspects for offshore wind turbines are considered: usually the wind loading are dominating the wave loading, wake effects in wind farms are important and the reliability level is typically significantly lower than...

  3. Assessment of Offshore Wind System Design, Safety, and Operation Standards

    Energy Technology Data Exchange (ETDEWEB)

    Sirnivas, Senu [National Renewable Energy Lab. (NREL), Golden, CO (United States); Musial, Walt [National Renewable Energy Lab. (NREL), Golden, CO (United States); Bailey, Bruce [AWS Trupower LLC, Albany, NY (United States); Filippelli, Matthew [AWS Trupower LLC, Albany, NY (United States)

    2014-01-01

    This report is a deliverable for a project sponsored by the U.S. Department of Energy (DOE) entitled National Offshore Wind Energy Resource and Design Data Campaign -- Analysis and Collaboration (contract number DE-EE0005372; prime contractor -- AWS Truepower). The project objective is to supplement, facilitate, and enhance ongoing multiagency efforts to develop an integrated national offshore wind energy data network. The results of this initiative are intended to 1) produce a comprehensive definition of relevant met-ocean resource assets and needs and design standards, and 2) provide a basis for recommendations for meeting offshore wind energy industry data and design certification requirements.

  4. Flight Leader Concept for Wind Farm Load Counting. Offshore evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Obdam, T.S.; Rademakers, L.W.M.M.; Braam, H. [ECN Wind Energy, Petten (Netherlands)

    2009-09-15

    ECN has developed a demo version of the Flight Leader model, which is based on a concept with which the accumulated mechanical loading of all turbines in an offshore wind farm can be estimated at acceptable costs. This information can be used to optimise and lower the cost of Operation and Maintenance (O and M), for example by prioritising inspections and replacements. In this paper the background and general concept of the Flight Leader model are presented. A full Flight Leader analysis has been performed using data from the Dutch offshore wind farm OWEZ (Offshore Wind farm Egmond aan Zee). In this paper the approach and results of the analyses are discussed.

  5. Design tool for offshore wind farm cluster planning

    DEFF Research Database (Denmark)

    Hasager, Charlotte Bay; Madsen, Peter Hauge; Giebel, Gregor

    2015-01-01

    In the framework of the FP7 project EERA DTOC: Design Tool for Offshore wind farm Cluster, a new software supporting the planning of offshore wind farms was developed, based on state-of-the-art approaches from large scale wind potential to economic benchmarking. The model portfolio includes WAs......P, FUGA, WRF, Net-Op, LCoE model, CorWind, FarmFlow, EeFarm and grid code compliance calculations. The development is done by members from European Energy Research Alliance (EERA) and guided by several industrial partners. A commercial spin-off from the project is the tool ‘Wind & Economy’. The software...

  6. Designing Offshore Super Grid for the Combined Operation of Offshore Wind Farms and Hydro Storage

    DEFF Research Database (Denmark)

    Grimaldi, Armando; Chen, Zhe; Chen, Peiyuan

    2009-01-01

    to the transmission and distribution of renewable energy among countries and could solve the problem caused by the wind variability. The technology and the configuration of offshore wind farms are analyzed in the first part of this paper. Then, different steps to design the Offshore Super Grid in the North Sea......The European commission decided in 2008 to reduce the dependency of imported primary energy sources and to promote the use of renewable energy. In particular, many offshore wind farms are planned in the North Sea between 2020 and 2030. Furthermore, the recent blackouts in Europe have shown...

  7. Offshore Wind Power Production in Critical Weather Conditions

    DEFF Research Database (Denmark)

    Cutululis, Nicolaos Antonio; Litong-Palima, Marisciel; Sørensen, Poul Ejnar

    2012-01-01

    Critical weather conditions, i.e. extreme winds will raise a lot of challenges when it comes to the secure operation of the whole European electric system with the future large scale offshore wind power. This is especially true for Denmark where the target is that wind power should provide 50...

  8. Design of support structures for offshore wind turbines

    NARCIS (Netherlands)

    van der Tempel, J.

    2006-01-01

    To meet growing energy demands, the Kyoto protocol and the much desired diversification of supply, wind energy has become a mainstream source of energy in the EU. Cost wise it is already competing with gas fired electricity. In the last decade wind moved offshore to accommodate even more wind power.

  9. Evaluation of wind farm efficiency and wind turbine wakes at the Nysted offshore wind farm

    DEFF Research Database (Denmark)

    Barthelmie, Rebecca Jane; Jensen, L.E.

    2010-01-01

    Here, we quantify relationships between wind farm efficiency and wind speed, direction, turbulence and atmospheric stability using power output from the large offshore wind farm at Nysted in Denmark. Wake losses are, as expected, most strongly related to wind speed variations through the turbine...... thrust coefficient; with direction, atmospheric stability and turbulence as important second order effects. While the wind farm efficiency is highly dependent on the distribution of wind speeds and wind direction, it is shown that the impact of turbine spacing on wake losses and turbine efficiency can...... be quantified, albeit with relatively large uncertainty due to stochastic effects in the data. There is evidence of the ‘deep array effect’ in that wake losses in the centre of the wind farm are under-estimated by the wind farm model WAsP, although overall efficiency of the wind farm is well predicted due...

  10. Offshore wind power systems in Schleswig-Holstein; Offshore in Schleswig-Holstein

    Energy Technology Data Exchange (ETDEWEB)

    Voigt, W. [Ministerium fuer Finanzen und Energie des Landes Schleswig-Holstein, Kiel (Germany)

    2002-07-01

    At a Rotarian meeting on Helgoland, Secretary of State Wilfried Voigt of the Schleswig-Holstein Energy Ministry held a much-discussed plea in favour of offshore wind power. [German] Anlaesslich einer Veranstaltung der Rotarier auf der Insel Helgoland hat Staatssekretaer Wilfried Voigt, Energieministerium Schleswig-Holstein, ein vielbeachtetes Plaedoyer fuer den Offshore Einsatz der Windenergie gehalten. (orig.)

  11. China: an emerging offshore wind development hotspot. With a new assessment of China's offshore wind potential

    Energy Technology Data Exchange (ETDEWEB)

    Reinvang, Rasmus; Enslow, Rachel; Beaumont, Hubert

    2010-08-15

    This study provides new and more detailed estimates of the offshore wind energy resources in China, with particular focus on Southern China. The study points out that the offshore wind industry is ramping up in China with at least 11.9GW in the development pipeline per April 2010. The study estimates the offshore wind potential of China (excluding Taiwan) to 11,580TWh/year. The study proves estimates and wind energy resource maps per province. Fujian, Zhejiang and Hainan stand out with the highest offshore wind speeds in China while Guangdong also shows significant potential, with annual wind speed averages of 6.5-10.2m/s and an energy density range of 12-36GWh/km2. Even though current offshore wind development is mainly taking place in Fujian and Jiangsu, this study shows that the potential is likely even greater in other provinces. The study was developed by the Chinese Wind Energy Association (CWEA) and Sun Yat-sen University, and commissioned by WWF as part of a project funded by the Norwegian Agency of development Coopeartion (Norad). Methodology and constraints: The wind resource analysis improves upon previous studies in estimating the wind energy generation potential for offshore wind power in China, with available meteorological data adjusted for influence of typhoons. The study models how much energy offshore wind can produce along China's coast up to 100km from the shore by calculating the energy output of theoretical wind farms by applying the power curve of a 3MW turbine at a 100m hub height. In addition the study further expands by giving special consideration to the deep-sea offshore potential at +50m water depths. The study focuses particularly on the coastline from Shandong down to Hainan. The final results provide good indication of the offshore wind resource in China when comparing one area to the other. The report can therefore be used as a preliminary tool to identifying most interesting provinces and locations for offshore wind

  12. Offshore wind potential evaluation and remote sensing imagery; Evaluation du potentiel eolien offshore et imagerie satellitale

    Energy Technology Data Exchange (ETDEWEB)

    Fichaux, N.

    2003-12-15

    Offshore wind energy may help to contribute to the respect of the Kyoto objectives by Europe. It is a key issue to struggle against global change. To sit the future offshore wind parks, it is necessary to accurately evaluate the spatial repartition of the wind potential. We demonstrate that the offshore wind potential shall be represented by maps of wind statistics. As remote sensing is a tool for measuring space physical phenomena, we evaluate its potentialities for mapping wind statistics. Space-borne scatterometers enables the obtention of wind statistics, but far from our areas of interest and at low spatial resolution. Synthetic Aperture Radar (SAR) enables the computation of high resolution wind maps over our areas of interest, but are unsuitable to compute wind statistics. We define the mathematical framework of a statistical method. That method enables to take advantage of both scatterometer and SAR to compute maps of wind statistics at high spatial resolution over the areas of interest. It enables remote sensing to be used operationally to map the offshore wind potential. (author)

  13. Offshore Wind Farm Research at the NWO Institutes

    NARCIS (Netherlands)

    J.A.S. Witteveen (Jeroen)

    2013-01-01

    htmlabstractFundamental scientific research is essential to take the necessary next step in offshore wind farm innovation. The NWO scientific research institutes play a central role in the Dutch knowledge infrastructure for disseminating scientific discoveries into industrial innovations. Multiple

  14. Soil Damping at Walney 2 Offshore Wind Farm

    DEFF Research Database (Denmark)

    Andersen, Lars

    The present report presents the results of a finite-element analysis carried out in order to quantify the soil damping for a specific offshore wind turbine to be placed at the Walney 2 site.......The present report presents the results of a finite-element analysis carried out in order to quantify the soil damping for a specific offshore wind turbine to be placed at the Walney 2 site....

  15. 2014–2015 Offshore Wind Technologies Market Report

    Energy Technology Data Exchange (ETDEWEB)

    Aaron Smith, Tyler Stehly, Walt Musial

    2015-09-30

    This report provides data and analysis to assess the status of the U.S. offshore wind industry through June 30, 2015. It builds on the foundation laid by the Navigant Consortium, which produced three market reports between 2012 and 2014. The report summarizes domestic and global market developments, technology trends, and economic data to help U.S. offshore wind industry stakeholders, including policymakers, regulators, developers, financiers, and supply chain participants, to identify barriers and opportunities.

  16. Offshore wind farm Bockstigen - installation and operation experience

    Energy Technology Data Exchange (ETDEWEB)

    Lange, B. [Risoe National Lab., Wind Energy and Atmospheric Physics Dept., Roskilde (Denmark); Aagaard, E.; Andersen, P.E.; Moeller, A. [Wind World af 1997 A/S, Noerresundby (Denmark); Niklasson, S.; Wickman, A. [Vindkompaniet, Degerhamn (Sweden)

    1999-03-01

    The first Swedish offshore wind farm Bockstigen is operating since March 1998 near the coast of Gotland. It was built as a demonstration project by the Swedish wind farm developer Vindkompaniet, the Danish wind turbine manufacturer Wind World and the British offshore construction company Seacore and partly funded under the EU-THERMIE program. Bockstigen is the fourth offshore wind farm world-wide. While at previous wind farms the main emphasis laid on the demonstration of the technical feasibility of offshore wind energy utilisation, Bockstigen was aimed at demonstrating its economic viability. A number of innovative concepts have been employed: Drilled monopile foundations were used to save costs. A new construction method has been applied making use of a jack-up barge. A new control system for the turbines and the whole wind farm was developed, which controls the maximum power output, the flicker and the reactive power consumption depending on online measurements of the actual grid state. These new developments have been implemented successfully. A substantial cost reduction compared to previous offshore projects could be achieved. (au)

  17. Quantifying the hurricane risk to offshore wind turbines.

    Science.gov (United States)

    Rose, Stephen; Jaramillo, Paulina; Small, Mitchell J; Grossmann, Iris; Apt, Jay

    2012-02-28

    The U.S. Department of Energy has estimated that if the United States is to generate 20% of its electricity from wind, over 50 GW will be required from shallow offshore turbines. Hurricanes are a potential risk to these turbines. Turbine tower buckling has been observed in typhoons, but no offshore wind turbines have yet been built in the United States. We present a probabilistic model to estimate the number of turbines that would be destroyed by hurricanes in an offshore wind farm. We apply this model to estimate the risk to offshore wind farms in four representative locations in the Atlantic and Gulf Coastal waters of the United States. In the most vulnerable areas now being actively considered by developers, nearly half the turbines in a farm are likely to be destroyed in a 20-y period. Reasonable mitigation measures--increasing the design reference wind load, ensuring that the nacelle can be turned into rapidly changing winds, and building most wind plants in the areas with lower risk--can greatly enhance the probability that offshore wind can help to meet the United States' electricity needs.

  18. Design tool for offshore wind farm cluster planning

    OpenAIRE

    HASAGER, Charlotte Bay; Madsen, Peter Hauge; Giebel, Gregor; Réthoré, Pierre-Elouan; Hansen, Kurt Schaldemose; Badger, Jake; Pena Diaz, Alfredo; Volker, Patrick; Badger, Merete; Karagali, Ioanna; Nicolaos Antonio CUTULULIS; Maule, Petr; Schepers, Gerard; Wiggelinkhuizen, J; Cantero, Elena

    2015-01-01

    In the framework of the FP7 project EERA DTOC: Design Tool for Offshore wind farm Cluster, a new software supporting the planning of offshore wind farms was developed, based on state-of-the-art approaches from large scale wind potential to economic benchmarking. The model portfolio includes WAsP, FUGA, WRF, Net-Op, LCoE model, CorWind, FarmFlow, EeFarm and grid code compliance calculations. The development is done by members from European Energy Research Alliance (EERA) and guided by several ...

  19. A GLANCE AT OFFSHORE WIND TURBINE FOUNDATION STRUCTURES

    Directory of Open Access Journals (Sweden)

    Jianhua Zhang

    2016-06-01

    Full Text Available Energy poverty and climate change are crucial issues we face in our societies. Offshore wind energy has been a reliable solution to both of these problems - solving our growing energy problems while reducing CO2 emission. Innovative foundation design is one of the setbacks faced by this industry. Designing and constructing a cost effective offshore wind farm is greatly hampered by technical and infrastructural challenges, especially in foundation structures. This paper provides a detailed overview of issues related to this problem, with the aim of eliminating the frequent misunderstandings which can arise among engineers and investors working in the offshore wind energy sector. It begins by investigating the latest data and recommendations regarding the design and deployment of various kinds of offshore wind turbine (OWT foundations. It provides a framework which enables us to study the different OWT foundations, including prototypes and their limitations. Various structural failure modes are highlighted and corrosion measures are presented. Moreover, various removal methods of support structures are put forward. Finally, this paper presents the setbacks preventing the spread of offshore wind energy and the future works for offshore wind energy applications.

  20. Denmark - supplier of competitive offshore wind solutions. Megavind's strategy for offshore wind research, development and demonstration

    Energy Technology Data Exchange (ETDEWEB)

    2010-12-15

    In May 2006, the Danish Government presented a report on promoting environmentally effective technology and established a number of innovative partnerships. The partnerships intend to strengthen public-private cooperation between the state, industry, universities and venture capital to accelerate innovation for a number of green technologies. The partnership for wind energy is called Megavind. Megavind's strategy for offshore wind describes the offshore challenges and suggests research, development and demonstration (RD and D) priorities to enable offshore wind power become to competitive with other energy technologies. The strategy lists key recommendations as well as key thematic priorities and for each of these a number of RD and D priorities. Under each thematic priority references are made to the European Strategic Energy Technology plan (SET-plan), which prioritises offshore wind RD and D in Europe. (LN)

  1. An assessment of the environmental effects of offshore wind farms

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-07-01

    This report focuses on the development of an approach to the formal environmental assessment of large-scale offshore wind farms around the UK coast which will be required by EU Directives. The legislative background and policy framework are outlined, and key issues to be addressed in the environmental assessment are highlighted. Available information on the manufacture and transportation of wind farm equipment, turbine and cable installation, operation of an offshore wind farm, and wind farm decommissioning is reviewed and recommendations are given. The role of offshore wind power in meeting the UK's commitment to reducing emissions of carbon dioxide and other greenhouse gases and its targets for generating 10% of the UK's electricity from renewable energy sources is discussed.

  2. U.S. Offshore Wind Manufacturing and Supply Chain Development

    Energy Technology Data Exchange (ETDEWEB)

    Hamilton, Bruce Duncan [Navigant Consulting, Inc.

    2013-02-22

    The objective of the report is to provide an assessment of the domestic supply chain and manufacturing infrastructure supporting the U.S. offshore wind market. The report provides baseline information and develops a strategy for future development of the supply chain required to support projected offshore wind deployment levels. A brief description of each of the key chapters includes: » Chapter 1: Offshore Wind Plant Costs and Anticipated Technology Advancements. Determines the cost breakdown of offshore wind plants and identifies technical trends and anticipated advancements in offshore wind manufacturing and construction. » Chapter 2: Potential Supply Chain Requirements and Opportunities. Provides an organized, analytical approach to identifying and bounding the uncertainties associated with a future U.S. offshore wind market. It projects potential component-level supply chain needs under three demand scenarios and identifies key supply chain challenges and opportunities facing the future U.S. market as well as current suppliers of the nation’s land-based wind market. » Chapter 3: Strategy for Future Development. Evaluates the gap or competitive advantage of adding manufacturing capacity in the U.S. vs. overseas, and evaluates examples of policies that have been successful . » Chapter 4: Pathways for Market Entry. Identifies technical and business pathways for market entry by potential suppliers of large-scale offshore turbine components and technical services. The report is intended for use by the following industry stakeholder groups: (a) Industry participants who seek baseline cost and supplier information for key component segments and the overall U.S. offshore wind market (Chapters 1 and 2). The component-level requirements and opportunities presented in Section 2.3 will be particularly useful in identifying market sizes, competition, and risks for the various component segments. (b) Federal, state, and local policymakers and economic development

  3. A Floating Offshore Wind Turbine in Extreme Wave Conditions

    DEFF Research Database (Denmark)

    Wehmeyer, Christof

    and purposes oriented design procedures are the backbone of a cost efficient offshore wind industry. Conventional engineering procedures for the assessment of extreme event impacts, i.e. ultimate limit state (ULS) analysis of floating structures, as they have been used in the oil and gas industry, neglect two...... and will even overtake bottom fixed foundation within the coming two decades, Bossler (2011). FOWTs are believed having a large potential of lowering the cost of energy (CoE). The CoE minimization is currently the main driver for technological development in the offshore wind industry. Therefore reliable...... important aspects, which make them non-conservative in use for FOWT: (A) The offshore wind industry intends to install floating structures at much lower water depth (from 50m onwards), than the offshore oil & gas industry (from 300m onwards). In such cases a linear wave theory approach might...

  4. Applicability of Synthetic Aperture Radar Wind Retrievals on Offshore Wind Resources Assessment in Hangzhou Bay, China

    DEFF Research Database (Denmark)

    Chang, Rui; Zhu, Rong; Badger, Merete

    2014-01-01

    ENVISAT advanced SAR (ASAR) for mapping wind resources with high spatial resolution. Around 181 collected pairs of wind data from SAR wind maps and from 13 meteorological stations in Hangzhou Bay are compared. The statistical results comparing in situ wind speed and SAR-based wind speed show a standard......In view of the high cost and sparse spatial resolution of offshore meteorological observations, ocean winds retrieved from satellites are valuable in offshore wind resource assessment as a supplement to in situ measurements. This study examines satellite synthetic aperture radar (SAR) images from...

  5. Wave Influenced Wind and the Effect on Offshore Wind Turbine Performance

    OpenAIRE

    Kalvig, Siri; Manger, Eirik; Bjørn H. Hjertager; Jakobsen, Jasna B.

    2014-01-01

    In this paper the effect of wave influenced wind on offshore wind turbines is studied numerically. The wave is seen as a dynamical roughness that influences the wind flow and hence the wind turbine performance. An actuator line representation of the NREL's 5 MW offshore baseline wind turbine is placed in a simulation domain with a moving mesh that resolves the ocean waves. These wave influenced wind turbine simulations, WIWiTS, show that the wave will influence the wind field at the turbine r...

  6. Analysis of Anholt offshore wind farm SCADA measurements

    DEFF Research Database (Denmark)

    Hansen, Kurt Schaldemose; Volker, Patrick; Pena Diaz, Alfredo

    SCADA measurements from the Danish Anholt offshore wind farm (ANH) for a period of 2½ years have been qualified. ANH covers 12 km × 22 km and is located between Djursland and the island Anholt in Kattegat, Denmark. This qualification encompasses identification of curtailment and idling periods......, start/stop events and a power curve control for each wind turbine in the wind farm. Data also include wind speed measurements from a nearby WindCube lidar and simulations from the WRF model for the same period as the SCADA. An equivalent wind speed (wsi) is derived from the combined power and pitch...

  7. U.S. Offshore Wind Manufacturing and Supply Chain Development

    Energy Technology Data Exchange (ETDEWEB)

    Hamilton, Bruce [Navigant Consulting, Inc., Burlington, MA (United States)

    2013-02-22

    This report seeks to provide an organized, analytical approach to identifying and bounding uncertainties around offshore wind manufacturing and supply chain capabilities; projecting potential component-level supply chain needs under three demand scenarios; and identifying key supply chain challenges and opportunities facing the future U.S. market and current suppliers of the nation’s landbased wind market.

  8. Centralized electricity generation in offshore wind farms using hydraulic networks

    NARCIS (Netherlands)

    Jarquin Laguna, A.

    2017-01-01

    The work presented in this thesis explores a new way of generation, collection and transmission of wind energy inside a wind farm, in which the electrical conversion does not occur during any intermediate conversion step before the energy has reached the offshore central platform. A centralized

  9. Stochastic dynamic stiffness of surface footing for offshore wind turbines

    DEFF Research Database (Denmark)

    Vahdatirad, Mohammadjavad; Andersen, Lars Vabbersgaard; Ibsen, Lars Bo

    2014-01-01

    Highlights •This study concerns the stochastic dynamic stiffness of foundations for large offshore wind turbines. •A simple model of wind turbine structure with equivalent coupled springs at the base is utilized. •The level of uncertainties is quantified through a sensitivity analysis. •Estimation...

  10. Simulating coastal effects on an offshore wind farm

    DEFF Research Database (Denmark)

    van der Laan, Paul; Pena Diaz, Alfredo; Volker, Patrick

    are build in the vicinity of a coastline. In this study, we simulate the effect of the Danish Peninsula Djursland on the Anholt offshore wind farm, using a Reynolds-averaged Navier-Stokes (RANS) setup.2 The coastline is modeled as a roughness change, the wind turbines are represented by actuator disks...

  11. Challenges in simulating coastal effects on an offshore wind farm

    Science.gov (United States)

    van der Laan, M. P.; Peña, A.; Volker, P.; Hansen, K. S.; Sørensen, N. N.; Ott, S.; Hasager, C. B.

    2017-05-01

    The effect of a coastline on an offshore wind farm is investigated with a Reynolds-averaged Navier-Stokes (RANS) model. The trends of the RANS model compare relatively well with results from a mesoscale model and measurements of wind turbine power. In addition, challenges of modeling a large domain in RANS are discussed.

  12. Challenges in simulating coastal effects on an offshore wind farm

    DEFF Research Database (Denmark)

    van der Laan, Paul; Peña, Alfredo; Volker, Patrick

    2017-01-01

    The effect of a coastline on an offshore wind farm is investigated with a Reynolds-averaged Navier-Stokes (RANS) model. The trends of the RANS model compare relatively well with results from a mesoscale model and measurements of wind turbine power. In addition, challenges of modeling a large domain...

  13. Virginia Offshore Wind Cost Reduction Through Innovation Study (VOWCRIS) (Poster)

    Energy Technology Data Exchange (ETDEWEB)

    Maples, B.; Campbell, J.; Arora, D.

    2014-10-01

    The VOWCRIS project is an integrated systems approach to the feasibility-level design, performance, and cost-of-energy estimate for a notional 600-megawatt offshore wind project using site characteristics that apply to the Wind Energy Areas of Virginia, Maryland and North Carolina.

  14. Cost-Optimal Structural Reliability of Offshore Wind Turbines

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard; Tarp-Johansen, N. J.

    2004-01-01

    Wind turbines for electricity production are increasing drastically these years both in production capability and in size. Offshore wind turbines with an electricity production more than 5 MW are now being produced. The main failure modes are fatigue failure of wings, hub, shaft and main tower...

  15. Overplanting in offshore wind power plants in different regulatory regimes

    DEFF Research Database (Denmark)

    Wolter, Christoph; Klinge Jacobsen, Henrik; Rogdakis, Georgios

    2016-01-01

    is performed by installing a larger wind power capacity than stipulated in the connection agreement with transmission system operators (TSOs). By developing a discounted cash flow (DCF) model, the paper investigates how both regulatory regimes and geographic characteristics of dedicated offshore wind...

  16. Bats in Dutch offshore wind farms in autumn 2012

    NARCIS (Netherlands)

    Lagerveld, S.; Jonge Poerink, B.; Haselager, R.; Verdaat, J.P.

    2014-01-01

    In the autumn of 2012, we conducted a pilot study with ultrasonic recorders to assess the occurrence of bats over the North Sea. At Offshore Wind Farm Egmond aan Zee (OWEZ) a recorder was installed at the meteorological mast and at Princess Amalia Wind Farm (PAWP) a recorder was attached to the

  17. Terminology Guideline for Classifying Offshore Wind Energy Resources

    Energy Technology Data Exchange (ETDEWEB)

    Beiter, Philipp [National Renewable Energy Lab. (NREL), Golden, CO (United States); Musial, Walt [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2016-09-01

    The purpose of this guideline is to establish a clear and consistent vocabulary for conveying offshore wind resource potential and to interpret this vocabulary in terms that are familiar to the oil and gas (O&G) industry. This involves clarifying and refining existing definitions of offshore wind energy resource classes. The terminology developed in this guideline represents one of several possible sets of vocabulary that may differ with respect to their purpose, data availability, and comprehensiveness. It was customized to correspond with established offshore wind practices and existing renewable energy industry terminology (e.g. DOE 2013, Brown et al. 2015) while conforming to established fossil resource classification as best as possible. The developers of the guideline recognize the fundamental differences that exist between fossil and renewable energy resources with respect to availability, accessibility, lifetime, and quality. Any quantitative comparison between fossil and renewable energy resources, including offshore wind, is therefore limited. For instance, O&G resources are finite and there may be significant uncertainty associated with the amount of the resource. In contrast, aboveground renewable resources, such as offshore wind, do not generally deplete over time but can vary significantly subhourly, daily, seasonally, and annually. The intent of this guideline is to make these differences transparent and develop an offshore wind resource classification that conforms to established fossil resource classifications where possible. This guideline also provides methods to quantitatively compare certain offshore wind energy resources to O&G resource classes for specific applications. Finally, this guideline identifies areas where analogies to established O&G terminology may be inappropriate or subject to misinterpretation.

  18. Design optimization of offshore wind farms with multiple types of wind turbines

    DEFF Research Database (Denmark)

    Feng, Ju; Shen, Wen Zhong

    2017-01-01

    capacity are also included. We solve the problem with a newly developed extended random search algorithm and tested it in a realistic design optimization problem based on the Horns Rev 1 offshore wind farm in Denmark. The optimized non-uniform designs are compared with their uniform counterparts. We find......Most studies on offshore wind farm design assume a uniform wind farm, which consists of an identical type of wind turbines. In order to further reduce the cost of energy, we investigate the design of non-uniform offshore wind farms, i.e., wind farms with multiple types of wind turbines and hub......-heights. Given a set of different types of wind turbines with a different default hub height for each type, we can specify the design of a wind farm by the types of turbines, number of turbines for each type, and turbine locations. We consider the optimization of such design to minimize the levelized cost...

  19. A New Approach for Offshore Wind Farm Energy Yields Calculation with Mixed Hub Height Wind Turbines

    DEFF Research Database (Denmark)

    Hou, Peng; Hu, Weihao; Soltani, Mohsen

    2016-01-01

    In this paper, a mathematical model for calculating the energy yields of offshore wind farm with mixed types of wind turbines is proposed. The Jensen model is selected as the base and developed to a three dimension wake model to estimate the energy yields. Since the wind turbines are with differe...... hub heights, the wind shear effect is also taken into consideration. The results show that the proposed wake model is effective in calculating the wind speed deficit. The calculation framework is applicable for energy yields calculation in offshore wind farms.......In this paper, a mathematical model for calculating the energy yields of offshore wind farm with mixed types of wind turbines is proposed. The Jensen model is selected as the base and developed to a three dimension wake model to estimate the energy yields. Since the wind turbines are with different...

  20. Available and announced offshore wind turbines; Beschikbare en aangekondigde offshore windturbines

    Energy Technology Data Exchange (ETDEWEB)

    Ilzhoefer, L.

    2012-04-15

    At the end of 2011, about 4000 MW of offshore wind capacity had been installed in Europe. With market shares of respectively 50% and 40%, Siemens and Vestas are the dominant manufacturers on this market. In the field of offshore wind, Siemens is primarily successful with its wind turbine type SET3,6 (3.6 MW) and Vestas with the V90 of 3.0 MW. The offshore wind turbines of other manufacturers that have a higher capacity do not play a significant role with their market share. [Dutch] In Europa was eind 2011 ongeveer 4000 MW offshore windvermogen geplaatst. Met een marktaandeel van resp. 50 en 40% zijn Siemens en Vestas op dit moment de dominerende fabrikanten op deze markt. Op offshore gebied is Siemens primair succesvol met haar windturbine van de SWT3,6 (3,6 MW) en Vestas met de V90 van 3,0 MW. Beschikbare offshore windturbines van andere fabrikanten met een hoger vermogen spelen op dit moment qua marktaandeel geen rol van betekenis.

  1. Mid-Atlantic Offshore Wind Interconnection and Transmission (MAOWIT)

    Energy Technology Data Exchange (ETDEWEB)

    Kempton, Willett [Univ. of Delaware, Newark, DE (United States)

    2016-04-05

    This project has carried out a detailed analysis to evaluate the pros and cons of offshore transmission, a possible method to decrease balance-of-system costs and permitting time identified in the DOE Office Wind Strategic Plan (DOE, 2011). It also addresses questions regarding the adequacy of existing transmission infrastructure and the ability of existing generating resources to provide the necessary Ancillary Services (A/S) support (spinning and contingency reserves) in the ISO territory. This project has completed the tasks identified in the proposal: 1. Evaluation of the offshore wind resource off PJM, then examination of offshore wind penetrations consistent with U.S. Department of Energy’s (DOE) targets and with their assumed resource size (DOE, 2011). 2. Comparison of piecemeal radial connections to the Independent System Operator (ISO) with connections via a high-voltage direct current (HVDC) offshore network similar to a team partner. 3. High-resolution examination of power fluctuations at each node due to wind energy variability 4. Analysis of wind power production profiles over the Eastern offshore region of the regional ISO to assess the effectiveness of long-distance, North- South transmission for leveling offshore wind energy output 5. Analysis of how the third and fourth items affect the need for ISO grid upgrades, congestion management, and demand for Ancillary Services (A/S) 6. Analysis of actual historic 36-hr and 24-hr forecasts to solve the unit commitment problem and determine the optimal mix of generators given the need to respond to both wind variability and wind forecasting uncertainties.

  2. Automatic Classification of Offshore Wind Regimes With Weather Radar Observations

    DEFF Research Database (Denmark)

    Trombe, Pierre-Julien; Pinson, Pierre; Madsen, Henrik

    2014-01-01

    Weather radar observations are called to play an important role in offshore wind energy. In particular, they can enable the monitoring of weather conditions in the vicinity of large-scale offshore wind farms and thereby notify the arrival of precipitation systems associated with severe wind...... and amplitude) using reflectivity observations from a single weather radar system. A categorical sequence of most likely wind regimes is estimated from a wind speed time series by combining a Markov-Switching model and a global decoding technique, the Viterbi algorithm. In parallel, attributes of precipitation...... systems are extracted from weather radar images. These attributes describe the global intensity, spatial continuity and motion of precipitation echoes on the images. Finally, a CART classification tree is used to find the broad relationships between precipitation attributes and wind regimes...

  3. The influence of humidity fluxes on offshore wind speed profiles

    Directory of Open Access Journals (Sweden)

    R. J. Barthelmie

    2010-05-01

    Full Text Available Wind energy developments offshore focus on larger turbines to keep the relative cost of the foundation per MW of installed capacity low. Hence typical wind turbine hub-heights are extending to 100 m and potentially beyond. However, measurements to these heights are not usually available, requiring extrapolation from lower measurements. With humid conditions and low mechanical turbulence offshore, deviations from the traditional logarithmic wind speed profile become significant and stability corrections are required. This research focuses on quantifying the effect of humidity fluxes on stability corrected wind speed profiles. The effect on wind speed profiles is found to be important in stable conditions where including humidity fluxes forces conditions towards neutral. Our results show that excluding humidity fluxes leads to average predicted wind speeds at 150 m from 10 m which are up to 4% higher than if humidity fluxes are included, and the results are not very sensitive to the method selected to estimate humidity fluxes.

  4. Effects of Offshore Wind Turbines on Ocean Waves

    Science.gov (United States)

    Wimer, Nicholas; Churchfield, Matthew; Hamlington, Peter

    2014-11-01

    Wakes from horizontal axis wind turbines create large downstream velocity deficits, thus reducing the available energy for downstream turbines while simultaneously increasing turbulent loading. Along with this deficit, however, comes a local increase in the velocity around the turbine rotor, resulting in increased surface wind speeds. For offshore turbines, these increased speeds can result in changes to the properties of wind-induced waves at the ocean surface. In this study, the characteristics and implications of such waves are explored by coupling a wave simulation code to the Simulator for Offshore Wind Farm Applications (SOWFA) developed by the National Renewable Energy Laboratory. The wave simulator and SOWFA are bi-directionally coupled using the surface wind field produced by an offshore wind farm to drive an ocean wave field, which is used to calculate a wave-dependent surface roughness that is fed back into SOWFA. The details of this combined framework are outlined. The potential for using the wave field created at offshore wind farms as an additional energy resource through the installation of on-site wave converters is discussed. Potential negative impacts of the turbine-induced wave field are also discussed, including increased oscillation of floating turbines.

  5. Classifying Vertical Wind Speed Profiles for Offshore Wind Resource and Available Power Assessment

    Science.gov (United States)

    St Pe, A.; Tippet, S.; Rabenhorst, S. D.; Delgado, R.

    2016-12-01

    Prior to offshore wind farm construction, an accurate estimate of preconstruction energy yield is required to optimize wind farm layout and justify the project's economic viability. Unfortunately, uncertainties exist during this stage due in-part to limited measurements to characterize the offshore wind resource and related uncertainties predicting a turbine's available power. To better understand these preconstruction energy yield uncertainties, Doppler wind lidar and other met-ocean measurements were collected offshore within Maryland's Wind Energy Area from July-August 2013. Given the diversity of vertical wind speed profile (VWP) observations, VWPs are classified based on the goodness-of-fit to several mathematical expressions. Results demonstrate on average VWP typevariability is related to the magnitude of hub-height (100m) wind speed and wind direction (i.e. offshore fetch), as power law, logarithmic-like, VWPs occur during slightly weaker, northeasterly flow, while more unexpected VWPs are associated with stronger, southwesterly flow, from land to sea. In addition, compared to power-law VWP classes, unexpected VWPs types demonstrate slightly warmer air and SSTs, as well as stable surface conditions. Classifying VWPs also provides a useful tool for relating preconstruction offshore wind resource and turbine available power uncertainties. Using an NREL 5MW offshore reference turbine's power curve, buoy extrapolated surface wind to hub-height (100m), lidar measured hub-height, and several Rotor Equivalent Wind (REW) available power estimates are compared. On average, traditional hub-height wind speed power yields the highest available power estimate, approximately 9-70 percent greater than other techniques. Further, unexpected VWPs demonstrate the greatest variability in critical superimposed meteorological controls known to impact turbine performance, thus yield greatest deviation from hub-height power and uncertainty between available power estimates

  6. Reactive Power and Voltage Control of Offshore Wind Farms

    OpenAIRE

    Jerkø, Anders

    2014-01-01

    There are several challenges related to reactive power and voltage control of HVAC transmission from offshore wind farms to the main grid, which need to be addressed when designing wind farms. One challenge is the variation of wind speeds and thereby also power production, which can make it difficult to operate the system within the grid code requirements. This Master s thesis focuses on finding beneficial operating strategies to solve these challenges. Various locations of a static var compe...

  7. Improving Maryland's Offshore Wind Energy Resource Estimate Using Doppler Wind Lidar Technology to Assess Microtmeteorology Controls

    Science.gov (United States)

    St. Pé, Alexandra; Wesloh, Daniel; Antoszewski, Graham; Daham, Farrah; Goudarzi, Navid; Rabenhorst, Scott; Delgado, Ruben

    2016-06-01

    There is enormous potential to harness the kinetic energy of offshore wind and produce power. However significant uncertainties are introduced in the offshore wind resource assessment process, due in part to limited observational networks and a poor understanding of the marine atmosphere's complexity. Given the cubic relationship between a turbine's power output and wind speed, a relatively small error in the wind speed estimate translates to a significant error in expected power production. The University of Maryland Baltimore County (UMBC) collected in-situ measurements offshore, within Maryland's Wind Energy Area (WEA) from July-August 2013. This research demonstrates the ability of Doppler wind lidar technology to reduce uncertainty in estimating an offshore wind resource, compared to traditional resource assessment techniques, by providing a more accurate representation of the wind profile and associated hub-height wind speed variability. The second objective of this research is to elucidate the impact of offshore micrometeorology controls (stability, wind shear, turbulence) on a turbine's ability to produce power. Compared to lidar measurements, power law extrapolation estimates and operational National Weather Service models underestimated hub-height wind speeds in the WEA. In addition, lidar observations suggest the frequent development of a low-level wind maximum (LLWM), with high turbinelayer wind shear and low turbulence intensity within a turbine's rotor layer (40m-160m). Results elucidate the advantages of using Doppler wind lidar technology to improve offshore wind resource estimates and its ability to monitor under-sampled offshore meteorological controls impact on a potential turbine's ability to produce power.

  8. Three-Dimensional Wind Profiling of Offshore Wind Energy Areas With Airborne Doppler Lidar

    Science.gov (United States)

    Koch, Grady J.; Beyon, Jeffrey Y.; Cowen, Larry J.; Kavaya, Michael J.; Grant, Michael S.

    2014-01-01

    A technique has been developed for imaging the wind field over offshore areas being considered for wind farming. This is accomplished with an eye-safe 2-micrometer wavelength coherent Doppler lidar installed in an aircraft. By raster scanning the aircraft over the wind energy area (WEA), a three-dimensional map of the wind vector can be made. This technique was evaluated in 11 flights over the Virginia and Maryland offshore WEAs. Heights above the ocean surface planned for wind turbines are shown to be within the marine boundary layer, and the wind vector is seen to show variation across the geographical area of interest at turbine heights.

  9. Three-dimensional wind profiling of offshore wind energy areas with airborne Doppler lidar

    Science.gov (United States)

    Koch, Grady J.; Beyon, Jeffrey Y.; Cowen, Larry J.; Kavaya, Michael J.; Grant, Michael S.

    2014-01-01

    A technique has been developed for imaging the wind field over offshore areas being considered for wind farming. This is accomplished with an eye-safe 2-μm wavelength coherent Doppler lidar installed in an aircraft. By raster scanning the aircraft over the wind energy area (WEA), a three-dimensional map of the wind vector can be made. This technique was evaluated in 11 flights over the Virginia and Maryland offshore WEAs. Heights above the ocean surface planned for wind turbines are shown to be within the marine boundary layer, and the wind vector is seen to show variation across the geographical area of interest at turbine heights.

  10. Structural health monitoring systems in difficult environments. Offshore wind turbines

    Energy Technology Data Exchange (ETDEWEB)

    Faulkner, P.; Cutter, P.; Owens, A. [Strainstall Monitoring, Midsomer Norton (United Kingdom)

    2012-07-01

    The paper discusses the design and capability of Structural Health Monitoring Systems (SHMS) deployed on Offshore Wind Turbines together with the management of the tasks and risks in the offshore environment. The application of SHMS in difficult environments is a particularly challenging task, where ease of installation, ruggedness and reliability of equipment is essential in providing the key information of the structural integrity of Offshore Wind Turbine Towers. This information is required to evaluate the structural response, status and remaining operational life of the structure. The installation and commissioning of such systems have a significant focus on safety and access to the structures where onsite retrofitting of sensors and instrumentation are carried out in the field. Experience has been gained during the installation and commissioning of over 30 systems that have been deployed in the field in the UK offshore sector over the last two year period. (orig.)

  11. Probabilistic maximum-value wind prediction for offshore environments

    DEFF Research Database (Denmark)

    Staid, Andrea; Pinson, Pierre; Guikema, Seth D.

    2015-01-01

    High wind speeds can pose a great risk to structures and operations conducted in offshore environments. When forecasting wind speeds, most models focus on the average wind speeds over a given period, but this value alone represents only a small part of the true wind conditions. We present......, convective available potential energy, Charnock, mean sea-level pressure and temperature, as given by the European Center for Medium-Range Weather Forecasts forecasts. The models are trained to predict the mean value of maximum wind speed, and the residuals from training the models are used to develop...

  12. Wind mapping offshore in coastal Mediterranean area using SAR images

    DEFF Research Database (Denmark)

    Calaudi, Rosamaria; Arena, Felice; Badger, Merete

    Satellite observations of the ocean surface from Synthetic Aperture Radars (SAR) provide information about the spatial wind variability over large areas. This is of special interest in the Mediterranean, where spatial wind information is only provided by sparse buoys, often with long periods...... of missing data. Here, we focus on evaluating the use of SAR for offshore wind mapping. Preliminary results from the analysis of SAR-based ocean winds in Mediterranean areas show interesting large scale wind flow features consistent with results from previous studies using numerical models and space borne...

  13. Modelling of power fluctuations from large offshore wind farms

    DEFF Research Database (Denmark)

    Sørensen, Poul Ejnar; Cutululis, Nicolaos Antonio; Vigueras-Rodriguez, Antonio

    2008-01-01

    This paper deals with modelling of power fluctuations from large wind farms. The modelling is supported and validated using wind speed and power measurements from the two large offshore wind farms in Denmark. The time scale in focus is from 1 min to a couple of hours, where significant power...... fluctuations have been observed from these wind farms. Power and wind speed are measured with 1 s sampling time in all individual wind turbines in almost 1 year, which provides a substantial database for the analyses. The paper deals with diversified models representing each wind turbine individually...... and with aggregation of a wind farm to be represented by a single large wind turbine model. Copyright (C) 2007 John Wiley & Sons, Ltd....

  14. A Combined Reliability Model of VSC-HVDC Connected Offshore Wind Farms Considering Wind Speed Correlation

    DEFF Research Database (Denmark)

    Guo, Yifei; Gao, Houlei; Wu, Qiuwei

    2017-01-01

    This paper proposes a combined reliability model of voltage source converter-based high voltage direct current (VSCHVDC) connected offshore wind farms (WFs) using the frequency and duration technique. Firstly, a two-dimensional multi-state WF model is developed considering wind speed variations......-HVDC system and wind speed correlation on the system reliability were analyzed. Sensitivity analyses were conducted to investigate the impact of repair time of the offshore VSC-HVDC system on system reliability....

  15. Offshore Substation Locating in Wind Farms Based on Prim Algorithm

    DEFF Research Database (Denmark)

    Hou, Peng; Hu, Weihao; Chen, Zhe

    2015-01-01

    to the electrical system layout, the optimal layout design work should be done with the consideration of the impact of the location of offshore substation on the submarine cable connection layout to minimize the investment of cables. This paper addresses a new method to optimize the OS location together...... with the cable connection layout. The results show that the proposed method is an effective way for offshore wind farm cable connection layout design....

  16. Damage Identification of an Offshore Wind Turbine Jacket Support Structure

    OpenAIRE

    Brauer, Simon Adrian

    2014-01-01

    Due to the variable and stochastic offshore environment, offshore wind turbines are prone to fatigue. Fatigue damage usually occurs as cracks and is an important indicator of the structure's condition and the remaining life-time. However, the detection of fatigue cracks today is very cumbersome and easier and more straight-forward methods are desirable. In this thesis, it is investigated whether fatigue damage can be identified or detected based on operational vibrations. The idea is that sen...

  17. Offshore wind power plants. Market trends and challenges; Offshore-Windkraftwerke. Marktentwicklung und Herausforderungen

    Energy Technology Data Exchange (ETDEWEB)

    Skiba, Martin [RWE Innogy GmbH, Essen (Germany); Reimers, Britta [TU Hamburg-Harburg (Germany). Inst. fuer Umwelttechnik und Energiewirtschaft

    2012-10-15

    The European offshore market is undergoing a critical phase. While grid connection and grid expansion problems in Germany make the situation of investors uncertain, Britain stopped its financial incentives programme, which also resulted in uncertainty. Successful expansion can only be achieved if the specific power generation cost can be cut. Apart from a cost comparison between onshore and offshore wind power, the article also presents options for cost reduction.

  18. A New Coordinated Voltage Control Scheme for Offshore AC Grid of HVDC Connected Offshore Wind Power Plants

    DEFF Research Database (Denmark)

    Sakamuri, Jayachandra N.; Cutululis, Nicolaos Antonio; Rather, Zakir Hussain

    2015-01-01

    This paper proposes a coordinated voltage control scheme (CVCS) which enhances the voltage ride through (VRT) capability of an offshore AC grid comprised of a cluster of offshore wind power plants (WPP) connected through AC cables to the offshore voltage source converter based high voltage DC (VS......V with active power balance (hence DC voltage) control assigned to the onshore converter, while frequency and AC voltage control at the offshore substation assigned to the offshore converter....

  19. Risk-based Inspection Planning Optimisation of Offshore Wind Turbines

    DEFF Research Database (Denmark)

    Ramirez, José Rangel; Sørensen, John Dalsgaard

    2011-01-01

    . Inspection and maintenance (I&M) costs for offshore sites are much larger than for onshore ones, making the choice of suitable I&M planning for minimising costs important. Risk-based inspection planning (RBI) for offshore installations represents a suitable methodology to identify the optimal maintenance...... and inspection strategies to ‘control’ the deterioration in facilities such as offshore wind turbines (OWT), where fatigue and corrosion are typically affecting these structures. This article considers an RBI approach applied to OWT based on the developed methodologies for oil and gas installations...

  20. Maintenance Planning of Offshore Wind Turbine using Condition Monitoring Information

    DEFF Research Database (Denmark)

    Ramírez, José G. Rangel; Sørensen, John Dalsgaard

    2009-01-01

    Deterioration processes such as fatigue and corrosion are typically affecting offshore structures. To "control" this deterioration, inspection and maintenance activities are developed. Probabilistic methodologies represent an important tool to identify the suitable strategy to inspect and control...... the deterioration in structures such as offshore wind turbines (OWT). Besides these methods, the integration of condition monitoring information (CMI) can optimize the mitigation activities as an updating tool. In this paper, a framework for risk-based inspection and maintenance planning (RBI) is applied for OWT...... incorporating CMI, addressing this analysis to fatigue prone details in welded steel joints at jacket or tripod steel support structures for offshore wind turbines. The increase of turbulence in wind farms is taken into account by using a code-based turbulence model. Further, additional modes t integrate CMI...

  1. A Floating Offshore Wind Turbine in Extreme Wave Conditions

    DEFF Research Database (Denmark)

    Wehmeyer, Christof

    on the different crest front steepness values of the single wave, which is embedded in the nonlinear irregular background sea state. It was concluded that the embedded wave approach provided a controlled and time efficient engineering tool also for the floating offshore wind turbine generators.......The PhD work evaluated the performance of engineering procedures, used in the design of bottom fixed offshore wind turbines, for the hydrodynamic ULS analysis of a FOWT tension leg platform (TLP). Dynamically sensitive topsides have been included and water depths were considered, where wave shapes...... and peak enhancement factors, based on cyclonic storm conditions (Wehmeyer et al., 2012). 2. Based on Wehmeyer et al. (2012), a physical model test campaign was drafted, where an industry inspired floating offshore wind turbine was tested (Wehmeyer et al., 2013). 3. A comparison of measured pitch responses...

  2. Weather radars – the new eyes for offshore wind farms?

    DEFF Research Database (Denmark)

    Trombe, Pierre-Julien; Pinson, Pierre; Vincent, Claire Louise

    2014-01-01

    inputs to prediction systems for anticipating changes in the wind fluctuation dynamics, generating improved wind power forecasts and developing specific control strategies. However, integrating weather radar observations into automated decision support systems is not a plug-and-play task......Offshore wind fluctuations are such that dedicated prediction and control systems are needed for optimizing the management of wind farms in real-time. In this paper, we present a pioneer experiment – Radar@Sea – in which weather radars are used for monitoring the weather at the Horns Rev offshore...... observed at Horns Rev and (iv) we discuss the future perspectives for weather radars in wind energy. Copyright © 2013 John Wiley & Sons, Ltd....

  3. Energy Dynamics of an Infinitely Large Offshore Wind Farm

    DEFF Research Database (Denmark)

    Frandsen, Sten Tronæs; Barthelmie, R.J.; Pryor, S.C.

    the reference scenario expects 35 GW of offshore wind capacity in 2020 and 120 GW in 2030. This is not unrealistic given targets for individual member countries e.g. the UK expects to install 33 GW by 2020 and Germany plans 25 GW by 2030. Given the economics of offshore wind energy the majority of development......, particularly in the near-term, can be expected in the higher resource, moderate water depths of the North Sea rather than the Mediterranean. There should therefore be significant interest in understanding the energy dynamics of the infinitely large wind farm – how wakes behave and whether the extraction...... of energy by wind turbines over a large area has a significant and lasting impact on the atmospheric boundary layer. Here we focus on developing understanding of the infinite wind farm through a combination of theoretical considerations, data analysis and modeling. Initial evaluation of power losses due...

  4. Wind Loads on Ships and Offshore Structures Estimated by CFD

    DEFF Research Database (Denmark)

    Aage, Christian; Hvid, S.L.; Hughes, P.H.

    1997-01-01

    Wind loads on ships and offshore structures could until recently be determined only by model tests, or by statistical methods based on model tests. By the development of Computational Fluid Dynamics or CFD there is now a realistic computational alternative available. In this paper, wind loads...... on a seagoing ferry and on a semisubmersible offshore platform have been estimated by CFD. The results have been compared with wind tunnel model tests and, for the ferry, a few full-scale measurements, and good agreement is obtained. The CFD method offers the possibility of a computational estimate of scale...... effects related to wind tunnel model testing. An example of such an estimate on the ferry is discussed. Due to the time involved in generating the computational mesh and in computing the solution, the CFD method is not at the moment economically competitive to routine wind tunnel model testing....

  5. Transmission of wave energy through an offshore wind turbine farm

    DEFF Research Database (Denmark)

    Christensen, Erik Damgaard; Johnson, Martin; Sørensen, Ole Rene

    2013-01-01

    The transmission of wave energy passing an offshore wind farm is studied. Three effects that can change the wave field are analysed, which is the A) energy dissipation due to drag resistance, B) wave reflection/diffraction from structures, and C) the effect of a modified wind field inside...... and on the lee side of the wind farm. The drag dissipation, A), is quantified by a quadratic resistance law. The effect of B) is parameterised based on 1st order potential theory. A method to find the amount of reflected and transmitted wave energy is developed based on the panel method WAMIT™ and a radiation...... condition at infinity. From airborne and Satellite SAR (Synthetic Aperture Radar) a model has been derived for the change of the water surface friction C) inside and on the lee side of the offshore wind farm. The effects have been implemented in a spectral wind wave model,MIKE21 SW, and a parametric study...

  6. The Crucial Records Number to Retrieve Offshore Directional Wind Distribution

    Science.gov (United States)

    Zhu, X.; Li, Z.; Yang, X.

    2017-02-01

    The wind energy production estimates are very important to a wind power project. And, the remote sensing technique has been widely used to obtain the offshore wind speed and direction which could be used to calculate the wind energy of potential wind farm. However, the directional wind energy distributions are rarely studied, which also play important roles in analysis of wind farms’ potential power. In this article, the minimum number of records to obtain offshore directional wind distribution is stated by simulation experiment on In-situ dataset. The NDBC buoy dataset is randomly and multiply sampled to build new dataset under different numbers of observation records, which vary from 21 to 800. The resample under the same number of observation is repeated for 100 times to build dataset group. The directional wind distribution of new dataset is compared with the one of original buoy dataset, and errors made by dataset with fewer records are calculated. Besides, the 10th largest error in the sampled dataset group, which have the same number of observation records, is regarded as the error bound for those dataset. The change rule of the error bound is shown by fitted curves. Based on the fitted curves, minimum number of records is calculated. By this simulation experiment, the minimum number of records to represent wind direction frequency is 350, and 800 for annual direction distributions of wind energy density. To reduce the number of records needed in retrieval, some methods are discussed and tested.

  7. Offshore wind power experiences, potential and key issues for deployment

    Energy Technology Data Exchange (ETDEWEB)

    Lemming, J.; Morthorst, P.E.; Clausen, Niels-Erik

    2009-01-15

    Wind power has been growing at spectacular rates. Today it is the largest non-hydro renewable power technology. Worldwide there is 74 GW of installed capacity which is 1.7% of power generation capacity and in 2006 it accounted for 0.82% of electricity production. However, offshore wind still only counts for a very small amount and development has only taken place in North European counties round the North Sea and the Baltic Sea over the last 15 years. Offshore wind is still some 50% more expensive than onshore wind, but more wind resources and lesser visual impacts from larger turbines are expected to compensate for the higher installation costs in the long term. Most offshore wind farms are installed in British, Swedish and Danish waters, and present-day costs of installing wind energy in the UK are between 1,200 to 1,600 GBP/kW (1,781 to 2,375 Euro/kW) offshore, while in Sweden investment costs were 1,800 Euro/kW, and in Denmark 1,200 to 1,700 Euro/kW, though investment costs for a new wind farm are expected be in the range of 2.0 to 2.2 mill. Euro/MW for a near-shore shallow depth facility. Future developments in offshore wind technology concerning aerodynamics, structural dynamics, structural design, machine elements, electrical design and grid integration could drive investment costs from present-day range of 1.9 to 2.2 mill. Euro/MW down to 1.35 - 1.54 mill.Euro/MW in 2050, which accounts for a reduction of costs of approx. 35%. In order to sum up progress and identify future research needs, the International Energy Agency (IEA) Wind agreement Task 11 should arrange a new meeting concerning long term research needs for reviewing 'the long term strategy for 2000 to 2020' from 2001, to come up with suggestions / recommendations on how to define and proceed with, the necessary research activities of the IEA Wind Agreement and governments involved on key wind issues related to offshore technologies. (au)

  8. Offshore coastal wind speed gradients: Issues for the design and development of large offshore windfarms

    DEFF Research Database (Denmark)

    Barthelmie, R.J.; Badger, Jake; Pryor, S.C.

    2007-01-01

    Simulations, from mesoscale numerical models, and analyses of in-situ and remote sensing data from offshore wind farms in Denmark, are used to examine both horizontal and vertical gradients of wind speeds in the coastal zone. Results suggest that the distance from the coastline over which wind...... and 70 km. The width of the coastal zone, and the wind's vertical (shear) and horizontal gradients within the coastal zone, depend on atmospheric stability. Although vertical wind speed profiles above 50 m are likely responding to additional factors such as the height of the boundary-layer, using...... a stability correction improves predictions of wind speed compared with the logarithmic profile. Modelling indicates that within the coastal zone, wind speeds at typical turbine hub-heights can change by 2 m/s over the horizontal extent of a large wind farm, depending on stability. However, if the fetch...

  9. Implementation of a new Foundations Concept for Offshore Wind Farms

    DEFF Research Database (Denmark)

    Ibsen, Lars Bo

    2008-01-01

    The foundation principles for the recent major offshore wind farm projects in Europe have been dominated by two types of foundation solutions, the gravitational foundation and the monopile. A fully operational 3.0 MW offshore wind turbine was installed on a prototype of the bucket foundation...... with a traditional monopile solution and the installation of the bucket foundation is much easier and does not require heavy installation equipment. In this paper the full-scale field installation of the prototype is described. A design procedure has been developed in cooperation with the certifying party in order...

  10. DC Collection Network Simulation for Offshore Wind Farms

    DEFF Research Database (Denmark)

    Vogel, Stephan; Rasmussen, Tonny Wederberg; El-Khatib, Walid Ziad

    2015-01-01

    The possibility to connect offshore wind turbines with a collection network based on Direct Current (DC), instead of Alternating Current (AC), gained attention in the scientific and industrial environment. There are many promising properties of DC components that could be beneficial such as......: smaller dimensions, less weight, fewer conductors, no reactive power considerations, and less overall losses due to the absence of proximity and skin effects. This work describes a study about the simulation of a Medium Voltage DC (MVDC) grid in an offshore wind farm. Suitable converter concepts...

  11. 2014-2015 Offshore Wind Technologies Market Report

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Aaron [National Renewable Energy Lab. (NREL), Golden, CO (United States); Stehly, Tyler [National Renewable Energy Lab. (NREL), Golden, CO (United States); Musial, Walter [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2015-09-01

    This report provides data and analysis to assess the status of the U.S. offshore wind industry through June 30, 2015. It builds on the foundation laid by the Navigant Consortium, which produced three market reports between 2012 and 2014. The report summarizes domestic and global market developments, technology trends, and economic data to help U.S. offshore wind industry stakeholders, including policymakers, regulators, developers, financiers, and supply chain participants, to identify barriers and opportunities. Title page contains link to associated data tables posted at http://www.nrel.gov/docs/fy15osti/64283_data_tables.xlsx.

  12. Comparative evaluation of different offshore wind turbine installation vessels for Korean west–south wind farm

    Directory of Open Access Journals (Sweden)

    Dang Ahn

    2017-01-01

    Full Text Available The purpose of this study is to evaluate various means of wind power turbines installation in the Korean west–south wind farm (Test bed 100 MW, Demonstrate site 400 MW. We presented the marine environment of the southwest offshore wind farm in order to decide the appropriate installation vessel to be used in this site. The various vessels would be WTIV (Wind turbine installation vessel, jack-up barge, or floating crane … etc. We analyzed the installation cost of offshore wind turbine and the transportation duration for each vessel. The analysis results showed the most suitable installation means for offshore wind turbine in the Korean west–south wind farm.

  13. Quantifying offshore wind resources from satellite wind maps: Study area the North Sea

    DEFF Research Database (Denmark)

    Hasager, Charlotte Bay; Barthelmie, Rebecca Jane; Christiansen, Merete B.

    2006-01-01

    analysis and application program (WAsP). An estimate of the wind resource at the new project site at Horns Rev is given based on satellite SAR observations. The comparison of offshore satellite scatterometer winds, global model data and in situ data shows good agreement. Furthermore, the wake effect......Offshore wind resources are quantified from satellite synthetic aperture radar (SAR) and satellite scatterometer observations at local and regional scale respectively at the Horns Rev site in Denmark. The method for wind resource estimation from satellite observations interfaces with the wind atlas...

  14. Optimal Structural Reliability of Offshore Wind Turbines

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard; Tarp-Johansen, N.J.

    2005-01-01

    The main failure modes of modern large wind turbines are fatigue failure of wings, hub, shaft and main tower, local buckling of main tower, and failure of the foundation. This paper considers reliability-based optimal design of wind turbines. Compared to onshore wind turbines and building...

  15. Satellite Remote Sensing in Offshore Wind Energy

    DEFF Research Database (Denmark)

    Hasager, Charlotte Bay; Badger, Merete; Astrup, Poul

    2013-01-01

    Satellite remote sensing of ocean surface winds are presented with focus on wind energy applications. The history on operational and research-based satellite ocean wind mapping is briefly described for passive microwave, scatterometer and synthetic aperture radar (SAR). Currently 6 GW installed...

  16. Development of Offshore Wind Recommended Practice for U.S. Waters: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Musial, W. D.; Sheppard, R. E.; Dolan, D.; Naughton, B.

    2013-04-01

    This paper discusses how the American Petroleum Institute oil and gas standards were interfaced with International Electrotechnical Commission and other wind turbine and offshore industry standards to provide guidance for reliable engineering design practices for offshore wind energy systems.

  17. Life cycle assessment of offshore and onshore sited wind farms

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2004-10-15

    This report makes up the final reporting for the project 'Life cycle assessment (LCA) of turbines Analysis of possibilities of product directed environmental optimisation'. The purpose of the project is to carry through a life cycle assessment of an offshore wind farm and an onshore wind farm, respectively, as a basis for assessment of environmental improvement possibilities for wind farms through their life cycles. Likewise, the results are used to elaborate an environmental declaration of contents for power delivered to the grid from both types of wind farms. The project states the environmental impact for electricity produced at Horns Reef offshore wind farm and Tjaereborg onshore wind farm, respectively, as representatives for contemporary Danish offshore wind farms and onshore wind farms, respectively. Tjaereborg onshore wind farm is placed at an utmost favourably location with regard to wind, which means that the production at this wind farm is high compared with other onshore wind farms in Denmark. The high production rate is a factor that is taken into account when assessing the impact on the environment emanating from this wind farm. The results of the environmental life cycle assessments that have been carried out for the two wind farms do not show significant variance. If it is taken into account that Tjaereborg onshore wind farm is placed utmost favourably, the comparison shows that power from an average located onshore wind farm would have a more adverse or corresponding environmental impact as an unfavourably located offshore wind farm. The results show that it is the turbines that causes the largest environmental impact and not to a very high extent the transmission grid. For the turbines, the all-important environmental contribution comes from manufacturing and removal of the turbines, as it is the materials that cause the large environmental strain. The operation of the wind farms gives practically no contribution to the total

  18. The influence of humidity fluxes on offshore wind speed profiles

    DEFF Research Database (Denmark)

    Barthelmie, Rebecca Jane; Sempreviva, Anna Maria; Pryor, Sara

    2010-01-01

    extrapolation from lower measurements. With humid conditions and low mechanical turbulence offshore, deviations from the traditional logarithmic wind speed profile become significant and stability corrections are required. This research focuses on quantifying the effect of humidity fluxes on stability corrected...... wind speed profiles. The effect on wind speed profiles is found to be important in stable conditions where including humidity fluxes forces conditions towards neutral. Our results show that excluding humidity fluxes leads to average predicted wind speeds at 150 m from 10 m which are up to 4% higher...... than if humidity fluxes are included, and the results are not very sensitive to the method selected to estimate humidity fluxes....

  19. Optimization of offshore wind farm layout in restricted zones

    DEFF Research Database (Denmark)

    Hou, Peng; Hu, Weihao; Chen, Cong

    2016-01-01

    In this research, an optimization method for offshore wind farm layout design is proposed. With the purpose of maximizing the energy production of the wind farm, the wind turbine (WT) positions are optimized. Due to the limitations of seabed conditions, marine traffic limitations or shipwrecks, etc...... with multiple adaptive methods (PSO-MAM) is adopted. The simulation results indicate that the proposed method can find a layout which outperforms a baseline layout of a reference wind farm (RWF) by increasing the energy yield by 3.84%....

  20. Influence of offshore wind farms layout on electrical resonances

    DEFF Research Database (Denmark)

    Holdyk, Andrzej; Holbøll, Joachim; Koldby, Erik

    2014-01-01

    , harmonics and interaction between components and the power system and especially on the interaction and resonance between the transformer,-cables and the circuit breaker. These phenomena are also important in offshore wind farms, where the specific and often complex structure of the collection grid can......, winding resistances and winding capacitances. Considering the frequency range of the present investigations, up to about 1 MHz, a lumped representation of the transformer characteristics was deemed sufficient. Breakers and capacitors are modelled as ideal components. The chosen wind farm layout includes...

  1. Cross-Wind Modal Properties of Offshore Wind Turbines Identified by Full Scale Testing

    DEFF Research Database (Denmark)

    Damgaard, Mads; Ibsen, Lars Bo; Andersen, Lars Vabbersgaard

    2013-01-01

    to additional costs, the structural response must be analysed with reliable estimations of the dynamic properties of the wind turbines. Based on a thorough investigation of “rotor-stop” tests performed on offshore wind turbines supported by a monopile foundation for different wind parks in the period 2006...

  2. Development of Seismic Demand for Chang-Bin Offshore Wind Farm in Taiwan Strait

    OpenAIRE

    Yu-Kai Wang; Juin-Fu Chai; Yu-Wen Chang; Ti-Ying Huang; Yu-Shu Kuo

    2016-01-01

    Taiwan is located on the Pacific seismic belt, and the soil conditions of Taiwan’s offshore wind farms are softer than those in Europe. To ensure safety and stability of the offshore wind turbine supporting structures, it is important to assess the offshore wind farms seismic forces reasonably. In this paper, the relevant seismic and geological data are obtained for Chang-Bin offshore wind farm in Taiwan Strait, the probabilistic seismic hazard analysis (PSHA) is carried out, and the first un...

  3. Offshore Wind Power Experiences, Potential and Key Issues for Deployment

    DEFF Research Database (Denmark)

    Lemming, Jørgen Kjærgaard; Morthorst, Poul Erik; Clausen, Niels-Erik

    Wind power has been growing at spectacular rates. Today it is the largest non-hydro renewable power technology. Worldwide there is 74 GW of installed capacity which is 1.7% of power generation capacity and in 2006 it accounted for 0.82% of electricity production. However, offshore wind still only......, machine elements, electrical design and grid integration could drive investment costs from present-day range of 1.9 to 2.2 mill.€/MW down to 1.35 - 1.54 mill.€/MW in 2050, which accounts for a reduction of costs of approx. 35% . In order to sum up progress and identify future research needs...... of the IEA Wind Agreement and governments involved on key wind issues related to offshore technologies....

  4. The 5 MW DeepWind floating offshore vertical wind turbine concept design - status and perspective

    DEFF Research Database (Denmark)

    Schmidt Paulsen, Uwe; Aagaard Madsen, Helge; Kragh, Knud Abildgaard

    2014-01-01

    Floating vertical-axis wind turbines for offshore wind energy present a concept with novelty and potentials for reducing COE. Cost reduction for offshore wind power plants is an industrial challenge, and DeepWind is - as the analysis of the current design shows-believed to be a good candidate in ......, that it is possible to achieve a competitive design ready for further industrial optimization. A preliminary analysis is provided on the emergency philosophy for this concept.......Floating vertical-axis wind turbines for offshore wind energy present a concept with novelty and potentials for reducing COE. Cost reduction for offshore wind power plants is an industrial challenge, and DeepWind is - as the analysis of the current design shows-believed to be a good candidate...... aspects of the floating hull, and new generator design embracing magnetic bearings. Two important design tools were developed which allow the industry to analyze various VAWT(vertical Axis Wind Turbine) variants for offshore applications: a main design tool “HAWC2” for aeroelastic design of VAWTs...

  5. Wind class sampling of satellite SAR imagery for offshore wind resource mapping

    DEFF Research Database (Denmark)

    Badger, Merete; Badger, Jake; Nielsen, Morten

    2010-01-01

    High-resolution wind fields retrieved from satellite synthetic aperture radar (SAR) imagery are combined for mapping of wind resources offshore where site measurements are costly and sparse. A new sampling strategy for the SAR scenes is introduced, based on a method for statistical-dynamical down......High-resolution wind fields retrieved from satellite synthetic aperture radar (SAR) imagery are combined for mapping of wind resources offshore where site measurements are costly and sparse. A new sampling strategy for the SAR scenes is introduced, based on a method for statistical......-dynamical downscaling of large-scale wind conditions using a set of wind classes that describe representative wind situations. One or more SAR scenes are then selected to represent each wind class and the classes are weighted according to their frequency of occurrence. The wind class methodology was originally...

  6. Offshore Wind Jobs and Economic Development Impact: Four Regional Scenarios (Presentation)

    Energy Technology Data Exchange (ETDEWEB)

    Tegen, S.

    2014-11-01

    NREL's Jobs and Economic Development Impact (JEDI) Model for Offshore Wind, is a computer tool for studying the economic impacts of fixed-bottom offshore wind projects in the United States. This presentation provides the results of an analysis of four offshore wind development scenarios in the Southeast Atlantic, Great Lakes, Mid-Atlantic, and Gulf of Mexico regions.

  7. Using Satellite SAR to Characterize the Wind Flow around Offshore Wind Farms

    Directory of Open Access Journals (Sweden)

    Charlotte Bay Hasager

    2015-06-01

    Full Text Available Offshore wind farm cluster effects between neighboring wind farms increase rapidly with the large-scale deployment of offshore wind turbines. The wind farm wakes observed from Synthetic Aperture Radar (SAR are sometimes visible and atmospheric and wake models are here shown to convincingly reproduce the observed very long wind farm wakes. The present study mainly focuses on wind farm wake climatology based on Envisat ASAR. The available SAR data archive covering the large offshore wind farms at Horns Rev has been used for geo-located wind farm wake studies. However, the results are difficult to interpret due to mainly three issues: the limited number of samples per wind directional sector, the coastal wind speed gradient, and oceanic bathymetry effects in the SAR retrievals. A new methodology is developed and presented. This method overcomes effectively the first issue and in most cases, but not always, the second. In the new method all wind field maps are rotated such that the wind is always coming from the same relative direction. By applying the new method to the SAR wind maps, mesoscale and microscale model wake aggregated wind-fields results are compared. The SAR-based findings strongly support the model results at Horns Rev 1.

  8. Numerical study of ocean wave effect on offshore wind farm

    Science.gov (United States)

    Shen, Lian; Yang, Di; Meneveau, Charles

    2013-11-01

    Wind power at sea has become increasingly important in renewable energy study. For energy harvesting, winds over oceans have many advantages over winds on land, for example, larger and open surface area, faster wind speed, and more wind resource close to high population regions. On the other hand, the presence of ocean waves introduces complexities to wind turbines. There is a critical need to study the dynamical interactions among marine atmospheric boundary layer, ocean wave field, and floating turbines. In this research, we study offshore wind farm by performing large-eddy simulations for winds coupled with potential-flow-theory based simulations for broadband irregular waves, with the wind turbines represented by an actuator disk model. Our results show that windseas at different development stages result in different sea-surface roughness and have an appreciable effect on wind profile and the energy extraction rate of the turbines. If swells are present, swell-to-wind momentum and energy transfer further changes the wind field to introduce oscillations in as well as modify the mean of the wind power. DY and LS acknowledge the support of NSF-CBET-1341062. CM acknowledges the support of NSF-AGS-1045189 and NSF-OISE-1243482.

  9. Examples of Important Ongoing Research Topics for Offshore Wind Energy

    DEFF Research Database (Denmark)

    Hansen, Martin Otto Laver; Bredmose, Henrik; Schløer, Signe

    2011-01-01

    The aim of the paper is to address some challenges related to offshore wind energy. A first example shows some results from an ongoing project on accurate computation of wave loads on monopole foundations. The effects of wave nonlinearity and bottom slope are examined and detailed CFD computations...

  10. Design Optimization of Piles for Offshore Wind Turbine Jacket Foundations

    DEFF Research Database (Denmark)

    Sandal, Kasper; Zania, Varvara

    Numerical methods can optimize the pile design. The aim of this study is to automatically design optimal piles for offshore wind turbine jacket foundations (Figure 1). Pile mass is minimized with constraints on axial and lateral capacity. Results indicate that accurate knowledge about soil...

  11. OWFgraph : A graph database for the offshore wind farm domain

    NARCIS (Netherlands)

    Quaeghebeur, E.R.G.; Sanchez Perez Moreno, S.; Zaayer, M.B.

    2017-01-01

    The construction and management of an offshore wind farm involves many disciplines, e.g. meteorology and economics. It is hard for a single researcher to keep an overview of all the relevant concepts, models, and tools from these disciplines. Nevertheless, this is needed when performing integrated

  12. Assessment approaches to logistics for offshore wind energy installation

    NARCIS (Netherlands)

    Vis, Iris F.A.; Ursavas, Evrim

    2016-01-01

    Offshore wind farm installation planning is highly complex, due to the high dependency on weather and the oversized components that impose specific constraints in areas such as transportation and lifting. Currently, there is very little transparency vis-à-vis the logistics challenges in the

  13. Risk-based Operation and Maintenance of Offshore Wind Turbines

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard

    2009-01-01

    For offshore wind turbines costs to operation and maintenance are substantial. This paper describes a risk-based lifecycle approach for optimal planning of operation and maintenance. The approach is based on pre-posterior Bayesian decision theory. Deterioration mechanisms such as fatigue, corrosion...

  14. Offshore Wind Potential in South India from Synthetic Aperture Radar

    DEFF Research Database (Denmark)

    Hasager, Charlotte Bay; Bingöl, Ferhat; Badger, Merete

    The offshore wind energy potential for pre-feasibility in South India in the area from 77° to 80° Eastern longitude and 7° to 10° Northern latitude is observed from a total of 164 ENVISAT Advanced Synthetic Aperture Radar (ASAR) satellite images during the years 2002 to 2011. All satellite scenes...

  15. Scour Around Monopile Foundations for Off-shore Wind Turbines

    DEFF Research Database (Denmark)

    Margheritini, Lucia; Frigaard, Peter B.; Martinelli, Luca

    2006-01-01

    Since the first offshore wind farm had been built (Vindeby Lolland 1991) the dimensions of the turbines are rising quickly: by now the diameter of the rotor reaches 90m and the pile diameter exceeds 4m. Monopile foundations, preferred to gravity ones for large pile diameters and shallow waters, s......, suffers from severe scour and the toe needs to be protected....

  16. Empowering sustainable niches: Comparing UK and Dutch offshore wind developments

    NARCIS (Netherlands)

    Kern, Florian; Verhees, Bram; Raven, Rob|info:eu-repo/dai/nl/41331927X; Smith, Adrian

    2015-01-01

    Abstract Offshore wind has been positioned as a promising technology that could play a major role in moving towards more sustainable energy systems, but deployment varies significantly across countries. This article aims to explain the contrast between the boom in the UK versus stagnation in The

  17. The (R)evolution of China: Offshore Wind Diffusion

    DEFF Research Database (Denmark)

    Poulsen, Thomas; Hasager, Charlotte Bay

    2017-01-01

    This research presents an industry level gap analysis for Chinese offshore wind, which serves as a way to illuminate how China may fast track industry evolution. The research findings provide insight into how the Chinese government strongly and systematically decrees state-owned Chinese firms to ...

  18. Optimization of pile design for offshore wind turbine jacket foundations

    DEFF Research Database (Denmark)

    Sandal, Kasper; Zania, Varvara

    The aim of this study is to use numerical methods of structural design optimization to design piles for offshore wind turbine jacket foundations. Pile mass is minimized with constraints on axial and lateral capacity. Results indicate that accurate knowledge about soil characteristics can translate...

  19. China, Norway and offshore wind development. A win-win wind relationship?

    Energy Technology Data Exchange (ETDEWEB)

    Enslow, Rachel

    2010-03-15

    This study published by WWF Norway, outlines the status of offshore wind power development in China and looks at how the Norwegian offshore industry can contribute to speed it up. Today China is the world's fastest growing market for renewable energy. China's annual offshore wind energy generation potential is 11,000 TWh, similar to that of the North Sea. The study estimates that in the next decade China will install 30 GW of offshore wind energy generation capacity. This could mitigate 1.3 billion tons of CO{sub 2} over the 20 year asset lifetime (more than the total Norwegian emissions forecast over the same period). To unleash China's potential and speed up development of offshore wind energy production, however, bridges must to be built between stakeholders with the relevant experience and the best available technology and policy makers and project developers in China. This study puts forward possible ways for future cooperation between China and Norway - a country with a world leading offshore industry cluster - in order to leverage mutual strengths to upscale and commercialize offshore wind technology for the global market. (Author)

  20. Modelling and Measuring Flow and Wind Turbine Wakes in Large Wind Farms Offshore

    DEFF Research Database (Denmark)

    Barthelmie, Rebecca Jane; Hansen, Kurt Schaldemose; Frandsen, Sten Tronæs

    2009-01-01

    Average power losses due to wind turbine wakes are of the order of 10 to 20% of total power output in large offshore wind farms. Accurately quantifying power losses due to wakes is, therefore, an important part of overall wind farm economics. The focus of this research is to compare different types...... power losses due to wakes and loads. The research presented is part of the EC-funded UpWind project, which aims to radically improve wind turbine and wind farm models in order to continue to improve the costs of wind energy. Reducing wake losses, or even reduce uncertainties in predicting power losses...

  1. Quantifying the Impact of Wind Turbine Wakes on Power Output at Offshore Wind Farms

    DEFF Research Database (Denmark)

    Barthelmie, Rebecca Jane; Pryor, Sara; Frandsen, Sten Tronæs

    2010-01-01

    There is an urgent need to develop and optimize tools for designing large wind farm arrays for deployment offshore. This research is focused on improving the understanding of, and modeling of, wind turbine wakes in order to make more accurate power output predictions for large offshore wind farms....... Detailed data ensembles of power losses due to wakes at the large wind farms at Nysted and Horns Rev are presented and analyzed. Differences in turbine spacing (10.5 versus 7 rotor diameters) are not differentiable in wake-related power losses from the two wind farms. This is partly due to the high...... of power output moving through the wind farm. Root-mean-square errors indicate a generally better model performance for higher wind speeds (10 rather than 6 m s−1) and for direct down the row flow than for oblique angles. Despite this progress, wake modeling of large wind farms is still subject...

  2. Quantifying the Hurricane Risk to Offshore Wind Power (Invited)

    Science.gov (United States)

    Apt, J.; Rose, S.; Jaramillo, P.; Small, M.

    2013-12-01

    The U.S. Department of Energy has estimated that over 50 GW of offshore wind power will be required for the United States to generate 20% of its electricity from wind. Developers are actively planning offshore wind farms along the U.S. Atlantic and Gulf coasts and several leases have been signed for offshore sites. These planned projects are in areas that are sometimes struck by hurricanes. Whether that risk will grow as a result of climate change is uncertain. Recent years have seen an increase in hurricane activity in the Atlantic basin (1) and, all else being equal, warmer sea surface temperatures can be expected to lead to increased storm intensity. We have developed a method to estimate the catastrophe risk to offshore wind power using simulated hurricanes (2). In Texas, the most vulnerable region we studied, 10% of offshore wind power could be offline simultaneously due to hurricane damage with a 100-year return period and 6% could be destroyed in any 10-year period. Much of the hurricane risk to offshore wind turbines can be mitigated by designing turbines for higher maximum wind speeds, ensuring that turbine nacelles can turn quickly to track the wind direction even when grid power is lost, and building in areas with lower risk. 1. Iris Grossmann and M. Granger Morgan, "Tropical Cyclones, Climate Change, and Scientific Uncertainty: What do we know, what does it mean, and what should be done?," Climatic Change, 108, pp 543-579, 2011. 2. Carnegie Mellon Electricity Industry Center Working Paper CEIC-13-07, http://wpweb2.tepper.cmu.edu/electricity/papers/ceic-13-07.asp This work was supported in part by the EPA STAR fellowship program, a grant from the Alfred P. Sloan Foundation and EPRI to the Carnegie Mellon Electricity Industry Center, and by the Doris Duke Charitable Foundation, the R.K. Mellon Foundation and the Heinz Endowments for support of the RenewElec program at Carnegie Mellon University. This research was also supported in part by the Climate and

  3. Advanced Offshore Wind Energy - Atlantic Consortium

    Energy Technology Data Exchange (ETDEWEB)

    Kempton, Willett

    2015-11-04

    This project developed relationships among the lead institution, U of Delaware, wind industry participants from 11 companies, and two other universities in the region. The participating regional universities were University of Maryland and Old Dominion University. Research was carried out in six major areas: Analysis and documentation of extreme oceanic wind events & their impact on design parameters, calibration of corrosivity estimates measured on a coastal turbine, measurment and modeling of tower structures, measurement and modeling of the tribology of major drive components, and gearbox conditioning monitoring using acoustic sensors. The project also had several educational goals, including establishing a course in wind energy and training graduate students. Going beyond these goals, three new courses were developed, a graduate certificate program in wind power was developed and approved, and an exchange program in wind energy was established with Danish Technical University. Related to the installation of a Gamesa G90 turbine on campus and a Gamesa-UD research program established in part due to this award, several additional research projects have been carried out based on mutual industry-university interests, and funded by turbine revenues. This award and the Gamesa partnership have jointly led to seven graduate students receiving full safety and climb training, to become “research climbers” as part of their wind power training, and contributing to on-turbine research. As a result of the educational program, already six graduate students have taken jobs in the US wind industry.

  4. A General Probabilistic Forecasting Framework for Offshore Wind Power Fluctuations

    DEFF Research Database (Denmark)

    Trombe, Pierre-Julien; Pinson, Pierre; Madsen, Henrik

    2012-01-01

    Accurate wind power forecasts highly contribute to the integration of wind power into power systems. The focus of the present study is on large-scale offshore wind farms and the complexity of generating accurate probabilistic forecasts of wind power fluctuations at time-scales of a few minutes...... fluctuations are characterized by highly volatile dynamics which are difficult to capture and predict. Due to the lack of adequate on-site meteorological observations to relate these dynamics to meteorological phenomena, we propose a general model formulation based on a statistical approach and historical wind...... power measurements only. We introduce an advanced Markov Chain Monte Carlo (MCMC) estimation method to account for the different features observed in an empirical time series of wind power: autocorrelation, heteroscedasticity and regime-switching. The model we propose is an extension of Markov...

  5. Offshore wind profiling using light detection and ranging measurements

    DEFF Research Database (Denmark)

    Pena Diaz, Alfredo; Hasager, Charlotte Bay; Gryning, Sven-Erik

    2009-01-01

    The advantages and limitations of the ZephlR (R), a continuous-wave, focused light detection and ranging (LiDAR) wind profiler, to observe offshore winds and turbulence characteristics were tested during a 6 month campaign at the tronsformer/platform of Hams Rev, the world's largest wind form......-derived friction velocities and roughness lengths were compared to Charnock's sea roughness model. These overage values were found to be close to the model, although the scatter of the individual estimations of sea roughness length was large. Copyright (C) 2008 John Wiley & Sons, Ltd....

  6. Extreme load predictions for floating offshore wind turbines

    DEFF Research Database (Denmark)

    Jensen, Jørgen Juncher

    2009-01-01

    An effective stochastic procedure for extreme value predictions related to wave and wind induced stochastic loads is applied to a tension-leg concept for floating offshore wind turbines. The method is based on the First Order Reliability Method (FORM) and as the procedure makes use of only short...... time-domain simulations all kinds of non-linearities can be included. The procedure has been used previously for wave induced loads and is in this note extended to combined wave and wind loads....

  7. Probabilistic Aspects of Harmonic Emission of Large Offshore Wind Farms

    DEFF Research Database (Denmark)

    Jensen, Christian Flytkjær; Bak, Claus Leth; Kocewiak, Lukasz Hubert

    2011-01-01

    of the harmonic emission. The simulated harmonic distortion at the PCC is compared to measurement. This reveals some diffi-culties regarding harmonic load flow studies. The harmonic background distortion in the grid to where the wind farm is connected must be included in the study. Furthermore, a very detailed......In this article, a new probabilistic method of as-sessment of harmonic emission of large offshore wind farms is presented. Based on measurements from the British wind farm Burbo Banks, probability density functions are estimated for the dominating low order harmonic currents injected by a single...

  8. Stability Boundaries for Offshore Wind Park Distributed Voltage Control

    DEFF Research Database (Denmark)

    Gryning, Mikkel P.S.; Wu, Qiuwei; Kocewiak, Lukasz

    2017-01-01

    In order to identify mechanisms causing slow reactive power oscillations observed in an existing offshore wind power plant, and be able to avoid similar events in the future, voltage control is studied in this paper for a plant with a static synchronous compensator, type-4 wind turbines and a park...... pilot control. Using data from the actual wind power plant, all stabilizing subsystem voltage proportional-integral controller parameters are first characterized based on their Hurwitz signature. Inner loop current control is then designed using Internal Mode Control principles, and guidelines for feed...

  9. Extreme wind conditions for a Danish offshore site

    DEFF Research Database (Denmark)

    Hansen, Kurt S.

    2000-01-01

    This paper presents an analysis of extreme wind speed gust values measured at a shallow water offshore site and at a coastal onshore site in Denmark. An estimate of 50-year extreme values has been evaluated using a new statistical method. In addition a mean gust shape is determined, based on a la...... on a large number of gusts. Finally the paper contains an estimate of extreme wind shear values.......This paper presents an analysis of extreme wind speed gust values measured at a shallow water offshore site and at a coastal onshore site in Denmark. An estimate of 50-year extreme values has been evaluated using a new statistical method. In addition a mean gust shape is determined, based...

  10. Risk-based Operation and Maintenance for Offshore Wind Turbines

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard; Nielsen, Jannie Jessen

    2011-01-01

    statistics and costs of the different operations. The different OM strategies are described and compared in an illustrative example with focus on which types of information that are needed. Special focus is on comparison between risk-based maintenance strategies and the conventional maintenance planning......For offshore wind turbines, costs to Operation and Maintenance (OM) are substantial, and can be expected to increase when wind farms are placed at deeper water depths and in more harsh environments. Traditional strategies for OM include corrective and preventive (scheduled and condition......-based) maintenance strategies. This paper describes a risk-based life-cycle approach for optimal planning of OM and design of offshore wind turbines. Damage accumulation models used to describe deterioration mechanisms such as fatigue, corrosion, wear and erosion are associated with significant uncertainty...

  11. Optimized Control Strategy For Over Loaded Offshore Wind Turbines

    DEFF Research Database (Denmark)

    Odgaard, Peter Fogh; Knudsen, Torben; Wisniewski, Rafal

    2015-01-01

    controller tuning for a given wind turbine. It also enables a very safe and robust comparison between a new control strategy and the present one. Main body of abstract Is it true that power de-rating indeed the best way to reduce loads? The power de-rating approach has the drawback of only indirectly......Abstract Optimized control strategy for overloaded offshore wind turbines Introduction Operation and maintenance cost are an important part of cost of energy especially for offshore wind farms. Typically unplanned service is called for due to detection off excessive loads on components, e...... as results of ensuring the load reduction to the given level. A MPC controller is configured and tuned using this novel approach including Pareto fronts. It is compared to the existing de-rating strategy using high fidelity aero-servo-elastic simulation code and the possibilities for reduction of cost...

  12. Radar sensitivity and antenna scan pattern study for a satellite-based Radar Wind Sounder (RAWS)

    Science.gov (United States)

    Stuart, Michael A.

    1992-01-01

    Modeling global atmospheric circulations and forecasting the weather would improve greatly if worldwide information on winds aloft were available. Recognition of this led to the inclusion of the LAser Wind Sounder (LAWS) system to measure Doppler shifts from aerosols in the planned for Earth Observation System (EOS). However, gaps will exist in LAWS coverage where heavy clouds are present. The RAdar Wind Sensor (RAWS) is an instrument that could fill these gaps by measuring Doppler shifts from clouds and rain. Previous studies conducted at the University of Kansas show RAWS as a feasible instrument. This thesis pertains to the signal-to-noise ratio (SNR) sensitivity, transmit waveform, and limitations to the antenna scan pattern of the RAWS system. A dop-size distribution model is selected and applied to the radar range equation for the sensitivity analysis. Six frequencies are used in computing the SNR for several cloud types to determine the optimal transmit frequency. the results show the use of two frequencies, one higher (94 GHz) to obtain sensitivity for thinner cloud, and a lower frequency (24 GHz) to obtain sensitivity for thinner cloud, and a lower frequency (24 GHz) for better penetration in rain, provide ample SNR. The waveform design supports covariance estimation processing. This estimator eliminates the Doppler ambiguities compounded by the selection of such high transmit frequencies, while providing an estimate of the mean frequency. the unambiguous range and velocity computation shows them to be within acceptable limits. The design goal for the RAWS system is to limit the wind-speed error to less than 1 ms(exp -1). Due to linear dependence between vectors for a three-vector scan pattern, a reasonable wind-speed error is unattainable. Only the two-vector scan pattern falls within the wind-error limits for azimuth angles between 16 deg to 70 deg. However, this scan only allows two components of the wind to be determined. As a result, a technique is

  13. Monitoring of offshore wind farm using reliable communication

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, K.G.; Gajranib, K.; Bhargavac, A. [Rajasthan Technical Univ.. Dept. of Electrical Engineering, Kota (India)

    2012-07-01

    Due to rapid exhaustion of fossil fuels, new renewable technologies for electricity generation are insisted upon to meet the continuous growing demand of energy all across the globe. Wind energy as a green energy is a favorable option, among other available renewable sources. The offshore wind farm capacity is growing rapidly, but it's uncertain and intermittent nature offers great challenges to power system engineers. The cost of repair and down time, results into extensive damage and reduced profitability. This necessitates the requirement of fast and reliable communication network for the monitoring and controlling of the wind farm. In this paper, we have proposed the communication network for medium offshore wind farm (160MW). The wind farm consists of four clusters; each cluster comprises of 10 Wind Turbines (WTs), each of capacity 4MW. A WT can be represented by nine logical nodes according to IEC-61400-25 standard. The functions of logical nodes are modeled in terms of analogue /status/control information. The wind farm has been modeled in OPNET modeler and the performance of the communication network is evaluated in terms of End to End delay and packet drop, using Synchronous Optical NETwork (SONET) standard. (Author)

  14. Transients in VSC-HVDC connected offshore wind power plant

    DEFF Research Database (Denmark)

    El-Khatib, Walid Ziad; Schwartzberg, D.; Arana Aristi, I.

    2015-01-01

    The focus of this paper is transient phenomena in VSC-HVDC connected offshore wind power plants (WPPs). With the help of a case study modelled in PSCAD simulation software, energisation events are analysed in the time domain. A comparison with more well-known results obtained at energisation of AC...... connected WPPs indicates that significant differences arise as the energy involved in the switching event increases, due to the presence of the HVDC converter control. The influence of the offshore HVDC converter control gain in the most critical cases is assessed empirically and explained qualitatively....

  15. Simulation-based evaluation of operation and maintenance logistics concepts for offshore wind power plants

    OpenAIRE

    Münsterberg, Torsten

    2017-01-01

    A modular simulation model for the operation of offshore wind power plants has been developed in this thesis. The model is able to represent offshore-based and onshore-based logistics concepts. Multiple simulation experiments have been conducted on different logistics concepts and offshore wind power plant scenarios. The investigation shows that for most German offshore wind power plants an onshore-based logistics concept is most cost-efficient.

  16. Fish benefits from offshore wind farm development

    DEFF Research Database (Denmark)

    Leonhard, Simon B.; Stenberg, Claus; Støttrup, Josianne

    2013-01-01

    moderately attractive to fish. Also investigations into the effects on fish and fish behaviour from electromagnetic fields were made at Nysted. Data documented some effects from the cable route on fish behaviour, with some species avoiding the cable, while other species were attracted. However, only flounder......The studies up until 2006 showed few effects on the fish fauna that could be attributed to the establishment and operation of the wind farms. Fish abundance and diversity were not higher inside the wind farms than in the areas outside the wind farms. One obvious reason for this could...... be that the studies and investigations were made during the early stages of colonisation of the turbine foundations at Horns Rev that constitute artificial reefs. At Nysted, the effect was weak, presumably because the benthic community consisted of a monoculture of large common mussels (Mytilus edulis) that are only...

  17. Impact of Hurricane Wind/Wave Misalignment on the Analyses of Fixed-Bottom Jacket Type Offshore Wind Turbine

    OpenAIRE

    Wei, Kai; Arwade, Sanjay R.; Myers, Andrew T.; Valamanesh, Vahid; Pang, Weichiang

    2015-01-01

    A high risk of hurricane is threatening the development of offshore wind energy in the east coast of the United States. Hurricane loads on an offshore wind turbine, namely wind and waves, not only exert large demands but also have rapidly changing characteristics, especially wind and wave directions. Waves are, in general, inert to rapid changes, whereas wind can change its properties within very short time scales. Misalignment of local winds and propagating ocean waves occurs regularly in a ...

  18. Load flow analysis for variable speed offshore wind farms

    DEFF Research Database (Denmark)

    Chen, Zhe; Zhao, Menghua; Blaabjerg, Frede

    2009-01-01

    A serial AC-DC integrated load flow algorithm for variable speed offshore wind farms is proposed. It divides the electrical system of a wind farm into several local networks, and different load flow methods are used for these local networks sequentially. This method is fast, more accurate, and many...... factors such as the different wind farm configurations, the control of wind turbines and the power losses of pulse width modulation converters are considered. The DC/DC converter model is proposed and integrated into load flow algorithm by modifying the Jacobian matrix. Two iterative methods are proposed...... and integrated into the load flow algorithm: one takes into account the control strategy of converters and the other considers the power losses of converters. In addition, different types of variable speed wind turbine systems with different control methods are investigated. Finally, the method is demonstrated...

  19. Optimized Power Dispatch Strategy for Offshore Wind Farms

    DEFF Research Database (Denmark)

    Hou, Peng; Hu, Weihao; Zhang, Baohua

    2016-01-01

    which are related to electrical system topology. This paper proposed an optimized power dispatch strategy (OPD) for minimizing the levelized production cost (LPC) of a wind farm. Particle swarm optimization (PSO) is employed to obtain final solution for the optimization problem. Both regular shape......Maximizing the power production of offshore wind farms using proper control strategy has become an important issue for wind farm operators. However, the power transmitted to the onshore substation (OS) is not only related to the power production of each wind turbine (WT) but also the power losses...... and irregular shape wind farm are chosen for the case study. The proposed dispatch strategy is compared with two other control strategies. The simulation results show the effectiveness of the proposed strategy....

  20. A CFD framework for offshore and onshore wind farm simulation

    Science.gov (United States)

    Avila, Matias; Gargallo-Peiró, Abel; Folch, Arnau

    2017-05-01

    We present a wind simulation framework for offshore and onshore wind farms. The simulation framework involves an automatic hybrid high-quality mesh generation process, a pre-processing to impose initial and boundary conditions, and a solver for the Reynolds Averaged Navier-Stokes (RANS) equations with two different turbulence models, a modified standard k-ɛ model and a realizable k-ɛ model in which we included the Coriolis effects. Wind turbines are modeled as actuator discs. The wind farm simulation framework has been implemented in Alya, an in-house High Performance Computing (HPC) multi-physics finite element parallel solver. An application example is shown for an onshore wind farm composed of 165 turbines.

  1. Offshore wind potential in South India from synthetic aperture radar

    Energy Technology Data Exchange (ETDEWEB)

    Hasager, C.B.; Bingoel, F.; Badger, M.; Karagali, I.; Sreevalsan, E.

    2011-10-15

    The offshore wind energy potential for pre-feasibility in South India in the area from 77 deg. to 80 deg. Eastern longitude and 7 deg. to 10 deg. Northern latitude is observed from a total of 164 ENVISAT Advanced Synthetic Aperture Radar (ASAR) satellite images during the years 2002 to 2011. All satellite scenes are from Wide Swath Mode and each cover approximately 400 km by 400 km. The ocean wind speed maps are retrieved and processed at Risoe DTU. The results show wind energy density from 200 W/m2 to 500 W/m2 at 10 m height above sea level. QuikSCAT ocean winds are included as background information on the 10-year mean and a general description of the winds and climate with monsoons in India is presented. (Author)

  2. Assessing vulnerability of marine bird populations to offshore wind farms.

    Science.gov (United States)

    Furness, Robert W; Wade, Helen M; Masden, Elizabeth A

    2013-04-15

    Offshore wind farms may affect bird populations through collision mortality and displacement. Given the pressures to develop offshore wind farms, there is an urgent need to assess population-level impacts on protected marine birds. Here we refine an approach to assess aspects of their ecology that influence population vulnerability to wind farm impacts, also taking into account the conservation importance of each species. Flight height appears to be a key factor influencing collision mortality risk but improved data on flight heights of marine birds are needed. Collision index calculations identify populations of gulls, white-tailed eagles, northern gannets and skuas as of particularly high concern in Scottish waters. Displacement index calculations identify populations of divers and common scoters as most vulnerable to population-level impacts of displacement, but these are likely to be less evident than impacts of collision mortality. The collision and displacement indices developed here for Scottish marine bird populations could be applied to populations elsewhere, and this approach will help in identifying likely impacts of future offshore wind farms on marine birds and prioritising monitoring programmes, at least until data on macro-avoidance rates become available. Copyright © 2013 Elsevier Ltd. All rights reserved.

  3. Analysis of North Sea Offshore Wind Power Variability

    Directory of Open Access Journals (Sweden)

    Aymeric Buatois

    2014-05-01

    Full Text Available This paper evaluates, for a 2030 scenario, the impact on onshore power systems in terms of the variability of the power generated by 81 GW of offshore wind farms installed in the North Sea. Meso-scale reanalysis data are used as input for computing the hourly power production for offshore wind farms, and this total production is analyzed to identify the largest aggregated hourly power variations. Based on publicly available information, a simplified representation of the coastal power grid is built for the countries bordering the North Sea. Wind farms less than 60 km from shore are connected radially to the mainland, while the rest are connected to a hypothetical offshore HVDC (High-Voltage Direct Current power grid, designed such that wind curtailment does not exceed 1% of production. Loads and conventional power plants by technology and associated cost curves are computed for the various national power systems, based on 2030 projections. Using the MATLAB-based MATPOWER toolbox, the hourly optimal power flow for this regional hybrid AC/DC grid is computed for high, low and medium years from the meso-scale database. The largest net load variations are evaluated per market area and related to the extra load-following reserves that may be needed from conventional generators.

  4. Dynamic Response of Offshore Wind Turbines subjected to Joint Wave and Wind Loads

    DEFF Research Database (Denmark)

    Liu, Weiliang; Chen, Jianbing; Liu, Wenfeng

    2013-01-01

    This paper investigates the dynamic response of offshore wind turbine systems subjected joint wind and wave loads. Relying on the finite element model, Kane’s equation is adopted to consider the rotation of blades. Besides, the generator-torque control and blade-pitch control are taken into consi...

  5. Wake losses optimization of offshore wind farms with moveable floating wind turbines

    NARCIS (Netherlands)

    S.F. Rodrigues; R. Teixeira Pinto (Rodrigo); M. Soleimanzadeh (Maryam); P.A.N. Bosman (Peter); P. Bauer (Pavol)

    2015-01-01

    htmlabstractIn the future, floating wind turbines could be used to harvest energy in deep offshore areas where higher wind mean speeds are observed. Currently, several floating turbine concepts are being designed and tested in small scale projects; in particular, one concept allows the turbine to

  6. Offshore and onshore wind turbine wake meandering studied in an ABL wind tunnel

    DEFF Research Database (Denmark)

    Barlas, Emre; Buckingham, Sophia; Glabeke, Gertjan

    2015-01-01

    Scaled wind turbine models have been installed in the VKI L1-B atmospheric boundary layer wind tunnel at offshore and onshore conditions. Time-resolved measurements were carried out with three component hot wire anemometry and stereo-PIV in the middle vertical plane of the wake up to eleven turbi...

  7. Wind turbines and transmission systems for offshore wind projects in planning stage

    Energy Technology Data Exchange (ETDEWEB)

    Madariaga, Ander; Martin, Jose Luis; Martinez de Alegria, Inigo; Zamora, Inmaculada [University of the Basque Country (UPV/EHU), Bilbao (Spain). Engineering Faculty; Ceballos, Salvador [Parque Tecnologico de Bizkaia, Derio (Spain). Tecnalia Research and Innovation

    2012-07-01

    This paper reviews the current situation of the offshore wind turbines (OWTs) and the transmission systems (TSs) for offshore wind projects in the planning stage. Bearing in mind that offshore wind projects can last between seven and ten years from the first environmental studies to the commissioning, research engineers from companies and academia consider the solutions already available, but also to the new proposals expected to be ready in time for the project under consideration. Regarding the wind energy conversion systems (WECSs) installed in the OWTs, their main characteristics are reviewed considering turbines in the 4.1 to 10.0 MW range. Regarding the TSs, the current situation of point-to-point HVAC and HVDC links is presented, as well as some ideas related to future DC grids currently under study. (orig.)

  8. Probabilistic Calibration of Fatigue Design Factors for Offshore Wind Turbine Support Structures

    DEFF Research Database (Denmark)

    Ramirez, José Rangel; Sørensen, John Dalsgaard

    2010-01-01

    for the considered offshore wind turbines in such a way that the specific uncertainties for the fatigue life are accounted in a rational manner. Similar approaches have been used for offshore oil & gas sub-structures, but the required reliability level for offshore wind turbines is generally lower and the fatigue...

  9. Energy Yield Prediction of Offshore Wind Farm Clusters at the EERA-DTOC European Project

    OpenAIRE

    Cantero, E.; Hasager, C. B.; Réthoré, P.-E.; A. Peña; Hansen, K; J. Badger; Schepers, J.G.; Faiella, L.M.; Iuga, D.; Giebel, G.; Lozano, S; SANZ, J.; Sieros, G.; Stuart, P; Young, T.

    2014-01-01

    A new integrated design tool for optimization of offshore wind farm clusters is under development in the European Energy Research Alliance – Design Tools for Offshore wind farm Cluster project (EERA DTOC). The project builds on already established design tools from the project partners and possibly third-party models. Wake models have been benchmarked on the Horns Rev and, currently, on the Lilgrund wind farm test cases. Dedicated experiments from ‘BARD Offshore 1’ wind farm will using scanni...

  10. Review of VSC HVDC Connection for Offshore Wind Power Integration

    DEFF Research Database (Denmark)

    Korompili, Asimenia; Wu, Qiuwei; Zhao, Haoran

    2016-01-01

    Voltage Source Converter (VSC) High Voltage Direct Current (HVDC) connection has become a new trend for long distance offshore wind power transmission. It has been confirmed by a lot of research that the maximum distance of a High Voltage Alternative Current (HVAC) sub-marine cable transmission...... system is limited due to surplus charging current of the cables. The VSC HVDC transmission system has the ability to overcome the limitation and offers other advantages over the HVAC transmission system. This paper is to review the VSC HVDC transmission technology and its application for offshore wind...... is given on the control methods of the VSC HVDC transmission system for fulfilling grid code requirements concerning Low Voltage Ride-Through (LVRT) and frequency regulation....

  11. Evaluation of offshore wind resources by scale of development

    DEFF Research Database (Denmark)

    Möller, Bernd; Hong, Lixuan; Lonsing, Reinhard

    Offshore wind energy has developed rapidly in terms of turbine and project size, and currently undergoes a significant up-scaling to turbines and parks at greater distance to shore and deeper waters. Expectations to the positive effect of economies of scale on power production costs, however, have...... can be explained by deeper water, higher distance to shore, bottlenecks in supply or higher raw material costs. The present paper addresses the scale of offshore wind parks for Denmark and invites to reconsider the technological and institutional choices made. Based on a continuous resource......-economic model operating in a geographical information systems (GIS) environment, which describes resources, costs and area constraints in a spatially explicit way, the relation between project size, location, costs and ownership is analysed. Two scenarios are presented, which describe a state...

  12. Evaluation of offshore wind resources by scale of development

    DEFF Research Database (Denmark)

    Möller, Bernd; Hong, Lixuan; Lonsing, Reinhard

    2012-01-01

    Offshore wind energy has developed rapidly in terms of turbine and project size, and currently undergoes a significant up-scaling to turbines and parks at greater distance to shore and deeper waters. Expectations to the positive effect of economies of scale on power production costs, however, have...... can be explained by deeper water, higher distance to shore, bottlenecks in supply or higher raw material costs. The present paper addresses the scale of offshore wind parks for Denmark and invites to reconsider the technological and institutional choices made. Based on a continuous resource......-economic model operating in a geographical information systems (GIS) environment, which describes resources, costs and area constraints in a spatially explicit way, the relation between project size, location, costs and ownership is analysed. Two scenarios are presented, which describe a state...

  13. The Offshore Wind Farm Array Cable Layout Problem

    DEFF Research Database (Denmark)

    Bauer, Joanna; Lysgaard, Jens

    2014-01-01

    In an offshore wind farm (OWF), the turbines are connected to a transformer by cable routes that cannot cross each other. Finding the minimum cost array cable layout thus amounts to a vehicle routing problem with the additional constraints that the routes must be embedded in the plane. For this p......In an offshore wind farm (OWF), the turbines are connected to a transformer by cable routes that cannot cross each other. Finding the minimum cost array cable layout thus amounts to a vehicle routing problem with the additional constraints that the routes must be embedded in the plane....... For this problem, both exact and heuristic methods are of interest. We optimize cable layouts for real-world OWFs by a hop-indexed integer programming formulation, and develop a heuristic for computing layouts based on the Clarke and Wright savings heuristic for vehicle routing. Our heuristic computes layouts...

  14. MIRARCO researcher cites case for offshore wind power

    Energy Technology Data Exchange (ETDEWEB)

    Tollinsky, Norm

    2011-09-15

    Mining companies in remote regions in Ontario use diesel power to generate electricity. The cost of diesel is high. Offshore wind energy is seen as a possible solution for these companies without grid power. However, the limiting factor with wind is that its rated capacity can only reach about 35% ideally. In addition, the factor of high feed-in tariff rates is also a concern. But the contribution of renewable energy to the provincial grid is so small that their influence on the economics of the market is extremely modest. The feed-in tariffs for renewable energy are set to provide early adopters with an incentive to innovate and embrace new technologies. The increase in electricity costs comes from paying for generating capacity that isn't being used rather than from the feed-in tariffs of renewable energy. In the United Kingdom, there are already two gigawatts of installed offshore energy, equivalent to two nuclear power stations.

  15. Review of VSC HVDC Connection for Offshore Wind Power Integration

    DEFF Research Database (Denmark)

    Korompili, Asimenia; Wu, Qiuwei; Zhao, Haoran

    2016-01-01

    Voltage Source Converter (VSC) High Voltage Direct Current (HVDC) connection has become a new trend for long distance offshore wind power transmission. It has been confirmed by a lot of research that the maximum distance of a High Voltage Alternative Current (HVAC) sub-marine cable transmission...... system is limited due to surplus charging current of the cables. The VSC HVDC transmission system has the ability to overcome the limitation and offers other advantages over the HVAC transmission system. This paper is to review the VSC HVDC transmission technology and its application for offshore wind...... power integration. Firstly, the main components, configuration and topology of the VSC HVDC transmission system are described. Secondly, the converter control system and control strategies are presented. Following that, the capabilities of the VSC HVDC technology are described. Finally, the focus...

  16. Fundamentals for remote condition monitoring of offshore wind turbine blades

    DEFF Research Database (Denmark)

    McGugan, Malcolm; Sørensen, Bent F.

    2007-01-01

    damage or failure in the Structural materials. The vision is of future blades containing sensors that give very early indications of any damage that is classed as critical or that is developing unacceptably rapidly. This early indication allows the option of changing operating conditions, and of a timely...... inspection, repair or replacement. The paper explores the requirements for the level of remote data Output that will allow an initial improvement in the overall management of offshore wind farms., and ultimately accurate estimates of remaining life for individual blades. The practical and theoretical...... software and hardware systems should be included. The paper also discusses the possible reasons for finding Such a proactive interest in SHM technology within offshore wind energy, where other industrial applications have exhibited more resistance....

  17. Quantifying the Available Offshore Wind Resource in North Carolina

    Science.gov (United States)

    Schutt, M.; Seim, H.

    2016-02-01

    We present a study of wind profile measurements for improvement upon the wind resource estimation of coastal North Carolina. The site of measurement, near Cape Hatteras, is interesting because of its proximity to an open sound condition to the north and west, as well as its oceanic boundary to the south and east, including the thermally dynamic influence of the Gulf Stream. Such an environment has been found to complicate wind speed estimation at wind turbine hub height. Early exploration of the profiles collected during 2012-2014 from the surface to 200 m revealed distinct characteristics unique to winds coming from Pamlico Sound, as compared to those coming from the Atlantic. In order to quantify the effect of atmospheric stability on the wind profiles, an aggregation of ancillary data was collected, including surface sea and air temperature, and surface humidity to calculate a Monin-Obukhov Similarity scaling parameter. The ancillary data, in combination with knowledge of upwind conditions, topography, and ocean thermal structure, is being used to test the ability of simple theory to reproduce the structure of wind profiles from the two environments assuming nested internal boundary layers. This work will provide a more refined method of estimating the available wind resource for use in offshore wind energy development in this particular coastal region.

  18. Offshore winds from a new generation of European satellites

    DEFF Research Database (Denmark)

    Badger, Merete; Karagali, Ioanna; Ahsbahs, Tobias Torben

    at sea. All are important for the planning, operation, and maintenance of offshore wind farms. Typical shortcomings of SAR-based wind fields include a low sampling frequency and a need for advanced data processing in order to retrieve the wind speed at 10 m above sea level. A new generation of European...... take place every day. DTU Wind Energy operates a system for processing of the raw SAR data to wind fields in near-real-time. The wind fields are available for download; for example by users in the wind energy community. Comparisons with mast and lidar observations have shown RMS errors of 1.3-1.5 m....../s as close as 1 km from the coastline. ESA’s Copernicus programme offers an Ocean Wind and Wave product (OWI), which allows users to bypass the processing of raw SAR data to wind and wave fields. The coverage is limited to the Mediterranean Sea at present but we can expect an expansion to other seas...

  19. Opportunities for offshore wind energy at the East Coast [of North America]; Offshore wind kansen aan de oostkust [van Noord-Amerika

    Energy Technology Data Exchange (ETDEWEB)

    Van der Meij-Kranendonk, J. [TWA Netwerk, Washington (United States)

    2012-01-15

    This report of the 5th North American Offshore Wind Executive Forum of 23 January 2012 offers an overview of the state of affairs with regard to offshore wind energy in the states of Maryland, Maine New Jersey, Virginia, North Carolina and the Great Lakes [Dutch] Dit verslag van het 5th North American Offshore Wind Executive Forum op 23 januari 2012 geeft een overzicht van de situatie op het gebied van offshore windenergie in de staten Maryland, Maine, New Jersey, Virginia, North Carolina en de Great Lakes.

  20. A Combined Reliability Model of VSC-HVDC Connected Offshore Wind Farms Considering Wind Speed Correlation

    OpenAIRE

    Guo, Yifei; Gao, Houlei; Wu, Qiuwei

    2017-01-01

    This paper proposes a combined reliability model of voltage source converter-based high voltage direct current (VSCHVDC) connected offshore wind farms (WFs) using the frequency and duration technique. Firstly, a two-dimensional multi-state WF model is developed considering wind speed variations and WTGs outage. The wind speed correlation between different WFs is included in the two-dimensional multistate WF model by using an improved k-means clustering method. Then, the entire system with two...

  1. Study on electricity transmission systems for offshore wind power

    OpenAIRE

    Lleonart Pizà, Aina

    2011-01-01

    This project presents the main features of each of the electricity transmission technologies available for offshore wind power and discusses their advantages and disadvantages in terms of technical, economic and environmental aspects. The transmission options studied are High Voltage Alternating Current (HVAC) and High Voltage Direct Current (HVDC). Within the HVDC there are two transmission technologies available, the classical Line Commutated Converter based HVDC and the most re...

  2. Offshore wind; proposed study areas; Havvind; forslag til utredningsomraader

    Energy Technology Data Exchange (ETDEWEB)

    Drivenes, Arvid; Eirum, Tale; Johnson, Nils Henrik; Mindeberg, Sigrun Kavli; Lunde, Synnoeve; Undem, Linn Silje; Veggeland, Kirsti; Veie-Rosvoll, Brit; Voksoe, Astrid

    2010-10-15

    The report suggests areas that may be suitable for establishing of offshore wind power, and should be further evaluated in a strategic environmental impact assessment, as it is designed to through Proposition. No. 107 (2008-2009). The proposed areas is shown in Figure 1 Eleven of the areas suitable for fixed installations and four sites suitable for floating installations. The work of the report has been carried out by a Directorate group led by the Norwegian Water Resources and Energy Directorate. (AG)

  3. Access Platforms for Offshore Wind Turbines Using Gratings

    DEFF Research Database (Denmark)

    Andersen, Thomas Lykke; Rasmussen, Michael R.

    2008-01-01

    The paper deals with forces generated by a stationary jet on different types of gratings and a solid plate. The force reduction factors for the different gratings compared to the solid plate mainly depend on the porosity of the gratings, but the geometry of the grating is also of some importance........ The derived reduction factors are expected to be applicable to design of offshore wind turbine access platforms with gratings where slamming also is an important factor....

  4. Cost reduction potentials of offshore wind power in Germany; Kostensenkungspotenziale der Offshore-Windenergie in Deutschland

    Energy Technology Data Exchange (ETDEWEB)

    Hobohm, Jens; Krampe, Leonard; Peter, Frank [Prognos AG, Berlin (Germany). Bereich Energiewirtschaft

    2014-01-15

    Offshore wind power is a major hope for the German energy turnaround. However, it will only be possible to tap its cost reduction potentials if industry, the political leadership and the administrative authorities join forces to create the necessary preconditions. An important requirement for this capital-intensive technology are stable legal and political framework conditions. A recent study on the future shows what needs to be done.

  5. Offshore wind farms in the local environment - an examination at Horns Rev Offshore Wind Farm. Background report; Havvindmoeller i lokalomraadet - en undersoegelse ved Horns Rev Havmoellepark. Baggrundsrapport

    Energy Technology Data Exchange (ETDEWEB)

    Kuehn, Susanne

    2005-07-01

    Horns Rev Offshore Wind Farm was built in 2002. A presentation is made of a sociological, qualitative survey on the local community's reception of the offshore wind farm. The survey aims at identifying attitudes towards the farm before and after the construction, with a view to identifying possible changes in attitudes, and explain the reasons for these (ml)

  6. Design of a New Foundation for Offshore Wind Turbines

    DEFF Research Database (Denmark)

    Ibsen, Lars Bo; Brincker, Rune

    2004-01-01

    as compared to a traditional pile foundation, it is much easier to install and it can easily be removed when the wind turbine is taken down. However, the new design is suffering from uncertainties in the accumulated fatigue in the both the steel structure and the surrounding earth material. Therefore an on......The gravitation platform and the monopile have in the previous major offshore wind turbine projects been dominating. A four-year research and development project has proven the bucket foundation to be feasible in suitable soil condition in water depth from near shore to app. 40 meters. A prototype...

  7. The (R)evolution of China: Offshore Wind Diffusion

    DEFF Research Database (Denmark)

    Poulsen, Thomas; Hasager, Charlotte Bay

    2017-01-01

    to expand into overseas markets to speed up learning efforts. Insights are offered regarding the nation-level strategic plans and institutional support policies mobilized by China in order to be able to conquer market shares internationally by building a strong home market and then facilitating an end...... successfully forge long-term alliances also for future Chinese wind energy export projects. Examples of past efforts of collaboration not yielding desired results have been included as well. At policy level, recommendations are provided on how the evolution of the Chinese offshore wind power industry can...

  8. Danish offshore wind. Key environmental issues - a follow-up

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2013-02-15

    This follow-up to the Danish environmental monitoring programme on large-scale offshore wind power builds on the result of the former programme of 2006 and focuses on updated knowledge on harbour porpoises, water birds and fish communities, and on the cumulative effects of wind farms. The scientific quality of the projects in this follow-up has been assessed by experts from the International Advisory Panel of Experts on Marine Ecology (IAPEME), who have commented on the results in an independent evaluation which is reproduced in this publication. (LN)

  9. Comparison of Calculation Approaches for Monopiles for Offshore Wind Turbines

    DEFF Research Database (Denmark)

    Augustesen, Anders Hust; Sørensen, Søren Peder Hyldal; Ibsen, Lars Bo

    2010-01-01

    Large-diameter (4 to 6m) monopiles are often used as foundations for offshore wind turbines. The monopiles are subjected to large horizontal forces and overturning moments and they are traditionally designed based on the p-y curve method (Winkler type approach). The p-y curves recommended......-dimensional continuum model established by means of the commercial program FLAC3D. The approaches are compared based on a monopile used as foundation for a wind turbine at Horns Rev which is located in the North Sea west of Denmark....

  10. Faults in the Collection Grid of Offshore Wind Farms

    DEFF Research Database (Denmark)

    Lunow, Morten Erlandsson; Holbøll, Joachim; Henriksen, Mogens

    2008-01-01

    This paper deals with transient conditions in the collection grid of offshore wind farms under different faults. A model of a standard wind farm was established in two versions, with a floating and a grounded collection grid respectively. Line to ground faults and three-phase to ground faults were...... applied at critical points at worst-case phase angle and the results compared. The simulations show that it is better with a grounded collection grid, since lack of a ground reference will prevent the system from recovering after a line to ground fault....

  11. Offshore wind power and nature protection. Requirements at offshore windparks in the German AWZ; Offshore-Windkraft und Naturschutz. Anforderungen an Offshore-Windparks in der deutschen AWZ

    Energy Technology Data Exchange (ETDEWEB)

    Daniels, Gero von; Uibeleisen, Maximilian [Kanzlei Freshfields Bruckhaus Deringer LLP, Berlin (DE). Bereich Environment, Planning and Regulatory (EPR)

    2011-12-15

    The rapid expansion of offshore windparks is the key to the success of the energy transition. It will be very glad to survey that offshore windparks are not available at free admission. The noise generated by ramming the piles of wind power plants into the seabed impairs porpoises, resting sea birds are scared away. The nature conservation law contains high hurdles for the impairment of the marine flora and fauna. There are only few insights into the marine environment. The German nature conservation law is focused on the terrestrial nature. With this in mind, the authors of the contribution reports on the nature conservation legal requirements for offshore wind parks and the resulting problems in practice.

  12. Comparison of wake models with data for offshore wind farms

    Energy Technology Data Exchange (ETDEWEB)

    Rados, K. [Robert Gordon Univ., School of Engineering, Aberdeen (United Kingdom); Larsen, G.; Barthelmie, R. [Risoe National Lab., Wind Energy Dept., Roskilde (Denmark); Schelz, W. [Garrad Hassan and Partners Ltd., Bristol (United Kingdom); Lange, B. [Oldenburg Univ., Dept. of Energy and Semiconductor Research EHF, Oldenburg (Germany); Schepers, G.; Hegberg, T. [Netherlands Energy Research Foundation ECN, Solar and Wind Energy Dept., Petten (Netherlands); Magnisson, M. [Uppsala Univ., Dept. of Earth Sciences, Meteorology, Uppsala (Sweden)

    2001-07-01

    A major objective of the ENDOW project is to evaluate the performance of wake models in offshore wind farm environments in order to ascertain the improvements required to enhance the prediction of power output within large offshore wind farms. The strategy for achieving this is to compare the performance of the models in a wide range of conditions which are expected to be encountered during turbine operation offshore. Six models of varying complexity have been evaluated initially against the Vindeby single wake data where it was found that almost all of them overestimate the wake effects and also significant inconsistencies between the model predictions appeared in the near wake and turbulence intensity results. Based on the conclusions of that study, the ENDOW wake modeling groups have already implemented a number of modifications to their original models. In the present paper, new single wake results are presented against experimental data at Vindeby and Bockstigen wind farms. Clearly, some of the model discrepancies previously observed in Vindeby cases have been smoothed and overall the performance is improved. (Author)

  13. Using Synthetic Aperture Radar Wind Measurements to support Offshore Wind Parks

    Science.gov (United States)

    Schneiderhan, T.; Lehner, S.; Horstmann, J.; Koch, W.; Schulz-Stellenfleth, J.

    2003-04-01

    In all countries with shallow coastal waters and a strong mean wind speed offshore wind parks are planned and built. The fast development of wind energy production in Europe led to an installation of more than 18 000 MW by the end of the year 2001. The installed offshore power up to date is about 100 MW. In the near future many projects for wind farms with an output of more than 5000 MW are planned. Some of these projects are already under construction. Offshore wind parks are showing a big potential for future energy production and solving ecological problems in reducing the CO^2 output. The construction and maintenance of offshore wind parks has to face the tough environmental conditions of the open sea resulting extensive maintenance and money. Therefore reliable forecast in particular of the wind and the ocean wave fields is essential. Space borne SAR data as acquired by the ERS satellites or the new ENVISAT satellite, launched in March 2002, provide two dimensional wind fields with a sub-kilometre resolution and a coverage of up to 500 by 500 km in the wide swath mode. They are thus ideally suited to investigate the spatial fine structure like e.g. turbulence in the wake of wind parks, which is an important factor in the optimal siting of wind farms. Due to their high coverage and resolution SAR data can provide information on the impact of the single turbines on the wind field experienced by the neighbouring turbines as well as the effect of the whole wind park on the local climate. This study shows the potential of two dimensional high resolution wind fields measured with space borne synthetic aperture radar to support the construction and operation of wind farms. The data can be used to minimize fatigue loading due to wind gusts as well as to provide short term power forecasts in order to optimise the power output. Examples of wind fields around the already existing offshore wind parks Utgrunden (South of Sweden) and Horns Rev (West of Denmark) and the

  14. Safety Evaluation of a Hybrid Substructure for Offshore Wind Turbine

    Directory of Open Access Journals (Sweden)

    Min-Su Park

    2016-01-01

    Full Text Available Towers and rotor-nacelles are being enlarged to respond to the need for higher gross generation of the wind turbines. However, the accompanying enlargement of the substructure supporting these larger offshore wind turbines makes it strongly influenced by the effect of wave forces. In the present study, the hybrid substructure is suggested to reduce the wave forces by composing a multicylinder having different radii near free surface and a gravity substructure at the bottom of the multicylinder. In addition, the reaction forces acting on the substructure due to the very large dead load of the offshore wind turbine require very firm foundations. This implies that the dynamic pile-soil interaction has to be fully considered. Therefore, ENSOFT Group V7.0 is used to calculate the stiffness matrices on the pile-soil interaction conditions. These matrices are then used together with the loads at TP (Transition Piece obtained from GH-Bladed for the structural analysis of the hybrid substructure by ANSYS ASAS. The structural strength and deformation are evaluated to derive an ultimate structural safety of the hybrid substructure for various soil conditions and show that the first few natural frequencies of the substructure are heavily influenced by the wind turbine. Therefore, modal analysis is carried out through GH-Bladed to examine the resonance between the wind turbine and the hybrid substructure.

  15. Anholt offshore wind farm winds investigated from satellite images

    DEFF Research Database (Denmark)

    Hasager, Charlotte Bay; Badger, Merete; Volker, Patrick

    at this particular moment and the backscatter from the wind turbines is much higher than that from the sea. Therefore the wind turbines are contrasted clearly as yellow/orange dots at the Anholt wind farm. Along the Swedish coast several ships (red dots) are visible. The SAR-based wind speeds can be trusted...... at around 1 km distance from any coastline except in grid cells with wind turbines, ships and other hard targets. The grid resolution is 1 km by 1 km. The wind direction is from the south west. The satellite SAR analysis is based on ~1.000 SAR images from Envisat ASAR recorded from August 2002 to April 2012......, i.e. before the wind farm was constructed. Based on these data the wind resource is estimated. Concurrent Sentinel-1 SAR data and available SCADA and lidar data, kindly provided by DONG Energy and partners, for the period January 2013 to June 2015 account for ~70 images, while ~300 images...

  16. Offshore wind speed and wind power characteristics for ten ...

    Indian Academy of Sciences (India)

    At Athos and Mykonos, increasing linear trends were estimated. At all the stations the chosen wind turbine could produce energy for more than 70% of the time. The wind speed distribution was found to be well represented by Weibull parameters obtained using Maximum likelihood method compared to WAsP and Method of ...

  17. Offshore Wind Initiatives at the U.S. Department of Energy

    Energy Technology Data Exchange (ETDEWEB)

    None, None

    2016-10-01

    Coastal and Great Lakes states account for nearly 80% of U.S. electricity demand, and the winds off the shores of these coastal load centers have a technical resource potential twice as large as the nation’s current electricity use. With the costs of offshore wind energy falling globally and the first U.S. offshore wind farm installed off the coast of Block Island, Rhode Island in 2016, offshore wind has the potential to contribute significantly to a clean, affordable, and secure national energy mix. To support the development of a world-class offshore wind industry, the U.S. Department of Energy has been supporting a broad portfolio of offshore wind research, development, and demonstration projects since 2011 and released a new National Offshore Wind Strategy jointly with the U.S. Department of the Interior in 2016.

  18. Offshore wind farms and their impact on North Sea stratification

    Science.gov (United States)

    Carpenter, J. R.; Clark, S.; Merckelbach, L.; Callies, U.; Gaslikova, L.; Baschek, B.

    2016-02-01

    In expanding wind energy generation to offshore regions, wind farms are now being operated and constructed in coastal seas that form a seasonal stratification. This stratification develops as increased solar radiation and heating warm the upper ocean in summer. It has a dominant influence on numerous ocean processes such as the growth and distribution of phytoplankton, as well as on the distribution of suspended sediment concentrations. The formation of stratification is opposed by turbulent mixing processes such as bottom boundary layer friction, and wave breaking in the surface mixed layer. However, as more wind farms are built in coastal areas that exhibit strong tidal currents, the turbulence generated as the currents interact with the wind farm foundation structures is expected to contribute to an enhanced mixing of the water column. This is especially true in the North Sea, where proposed wind farm developments comprise thousands of wind mills occupying a significant fraction of the offshore area. With these proposed developments in mind, we examine whether it is possible for the turbulence and mixing generated by these structures to have an impact on the formation of stratification. This is done by combining a series of idealized mixing models with both in-situ observations and numerical modeling of the North Sea. The results show that it is possible for the wind farms to have an influence on the large-scale stratification of the North Sea, but only when the development is particularly dense and widespread. Most important, we find that the amount of mixing is sensitive to both the type and placement of the wind farm foundation structures, as well as on the evolution of the stratification - both of which are currently not well known.

  19. Potential of Offshore Wind Energy and Extreme Wind Speed Forecasting on the West Coast of Taiwan

    Directory of Open Access Journals (Sweden)

    Pei-Chi Chang

    2015-02-01

    Full Text Available It is of great importance and urgency for Taiwan to develop offshore wind power. However, relevant data on offshore wind energy resources are limited. This study imported wind speeds measured by a tidal station and a buoy into the software WAsP to estimate the high-altitude wind speeds in the two areas. A light detection and ranging (Lidar system was set up near the tidal station and buoy. High-altitude wind speeds measured by the Lidar system were compared with the WAsP-estimated values, and it was discovered that the two data sets were consistent. Then, long-term wind speed data observed by buoys and tidal stations at various locations were imported into WAsP to forecast wind speeds at heights of 55–200 m on the west coast of Taiwan. The software WAsP Engineering was used to analyze the extreme wind speeds in the same areas. The results show that wind speeds at 100 m are approximately 9.32–11.24 m/s, which means that the coastal areas of west Taiwan are rich in wind energy resources. When a long-term 10-min average wind speed is used, the extreme wind speed on the west coast is estimated to be between 36.4 and 55.3 m/s.

  20. Towards a Joint Action Plan for Research and Development in the Offshore Wind Service Industry

    DEFF Research Database (Denmark)

    Andersen, Per Dannemand; Piirainen, Kalle A.; Clausen, Niels-Erik

    levelized cost of energy. Hence, reducing the cost of OWS is a major challenge for the wind industry. Furthermore, the North Sea is currently the most important site for offshore wind installations, and industry clusters based on OWSare emerging in regions around the North Sea.The JAP is a result......The poster presents a joint action plan (JAP) for research and development and innovation (RDI) in the offshore wind service industry in Denmark, Germany,Norway and the UK. Offshore wind servicing (OWS) is in this context defined as both assembly and installation of offshore wind farms as well...

  1. Impact of Offshore Wind Power Variability on the Frequency Stability of European Power System

    DEFF Research Database (Denmark)

    Cutululis, Nicolaos Antonio; Litong-Palima, Marisciel; Sørensen, Poul Ejnar

    2014-01-01

    Offshore wind power development scenarios are very ambitious. In Europe, it is expected to surpass 100 GW by 2030. As opposed to onshore, offshore wind will be concentrated in relatively small geographical areas, meaning that the geographical smoothening would be diminished. Being able to simulat...... the current dimensioning incidents values. This indicates that wind power variability should be considered in frequency stability.......Offshore wind power development scenarios are very ambitious. In Europe, it is expected to surpass 100 GW by 2030. As opposed to onshore, offshore wind will be concentrated in relatively small geographical areas, meaning that the geographical smoothening would be diminished. Being able to simulate...

  2. Offshore Wind Resources Assessment from Multiple Satellite Data and WRF Modeling over South China Sea

    DEFF Research Database (Denmark)

    Chang, Rui; Rong, Zhu; Badger, Merete

    2015-01-01

    offshore winds which can be used for offshore wind resource assessment. First, wind speeds retrieved from Synthetic Aperture Radar (SAR) and Scatterometer ASCAT images were validated against in situ measurements from seven coastal meteorological stations in South China Sea (SCS). The wind roses from...... (SD) of 2.09 m/s (1.83 m/s) and correlation coefficient of R 0.75 (0.80). When the offshore winds (i.e., winds directed from land to sea) are excluded, the comparison results for wind speeds show an improvement of SD and R, indicating that the satellite data are more credible over the open ocean...

  3. Baltic 2 offshore wind farm. Challenges and solutions during design and erection of a 288 MW offshore wind power plant; Baltic 2 Offshore Windpark. Herausforderungen und Loesungen waehrend der Design- und Errichtungsphase eines 288 MW Offshore-Windkraftwerks

    Energy Technology Data Exchange (ETDEWEB)

    Stamatelopoulos, Georg-Nikolaus; Kansy, Stefan [EnBW Energie Baden-Wuerttemberg AG, Stuttgart (Germany); Hannibal, John Michael [Siemens AG, Hamburg (Germany). Wind Power and Renewables Div.; Frettloehr, Bjoern [EnBW Energie Baden-Wuerttemberg AG, Hamburg (Germany). Wind und Maritime Technik

    2015-05-01

    Offshore wind offers a great potential for reliable power supply with markedly less future costs. However, offshore also means special requirements related to transport and installation at sea. Even if these requirements alone are very stringent, they are not the only ones that apply. Meeting these challenges requires project organisation comparable to other major projects.

  4. Quarter-Century Offshore Winds from SSM/I and WRF in the North Sea and South China Sea

    DEFF Research Database (Denmark)

    Hasager, Charlotte Bay; Astrup, Poul; Zhu, Rong

    2016-01-01

    We study the wind climate and its long-term variability in the North Sea and South China Sea, areas relevant for offshore wind energy development, using satellite-based wind data, because very few reliable long-term in-situ sea surface wind observations are available. The Special Sensor Microwave...... by 0.1 m/s at Fino1 in the North Sea, while west of Hainan in the South China Sea the difference is 1.0 m/s. Linear regression between SSM/I and WRF winds at 100 m show correlation coefficients squared of 0.75 and 0.67, standard deviation of 1.67 m/s and 1.41 m/s, and mean difference of −0.12 m/s and 0.......83 m/s for Fino1 and Hainan, respectively. The WRF-derived winds overestimate the values in the South China Sea. The inter-annual wind speed variability is estimated as 4.6% and 4.4% based on SSM/I at Fino1 and Hainan, respectively. We find significant changes in the seasonal wind pattern at Fino1...

  5. High resolution wind measurements for offshore wind energy development

    Science.gov (United States)

    Nghiem, Son Van (Inventor); Neumann, Gregory (Inventor)

    2013-01-01

    A method, apparatus, system, article of manufacture, and computer readable storage medium provide the ability to measure wind. Data at a first resolution (i.e., low resolution data) is collected by a satellite scatterometer. Thin slices of the data are determined. A collocation of the data slices are determined at each grid cell center to obtain ensembles of collocated data slices. Each ensemble of collocated data slices is decomposed into a mean part and a fluctuating part. The data is reconstructed at a second resolution from the mean part and a residue of the fluctuating part. A wind measurement is determined from the data at the second resolution using a wind model function. A description of the wind measurement is output.

  6. Wind power potential outside the Norwegian coast (offshore); Vindkraftpotensialet utenfor norskekysten (offshore)

    Energy Technology Data Exchange (ETDEWEB)

    Hofstad, Knut; Tallhaug, Lars

    2008-07-01

    Norway has a long coastline with good wind conditions, but is different from many other European countries because a big part of the maritime zone close to the coast is very deep (the Norwegian trench). Thus it is only possible to utilize a small part of the offshore field for wind power with today's technology. Developing wind power offshore is today only extended to the areas with shallow water with depth between 5 and 20 meters. The solution for the deeper areas is not commercially available as of yet, but more and more participants, a Norwegian firm (Owec) among others, are working on solutions that will make it possible to establish wind turbines with a solid base as deep as 100 meters (technology based on experiences from the oil industry). A considerable wind power potential in the shallow water areas outside the Norwegian coast has been proven. Meanwhile the potential is strongly dependent on the demand that the generating station must have a minimum distance from the shore. In areas with depths shallower than 20 meters, the potential is estimated from about 6000 to about 30 000 MW, dependent on if the minimum distance from shore is 10 to 1 km. If the maximum depth is extended to 50 m, the potential is about 13 000 to 55 000 MW. Also an approximation is made on how big the wind power potential can be if the maximum depth is extended to 100 m. The potential for wind power will then improve substantially and will be in the area from 40 000 to 140 000 MW. For depths that deep, it may also be pertinent to increase the demand for minimum distance from the shore to 20 km. The potential outside the 20 km limit will be about 12 000 MW. The investigation considers that the development shall not take place in the protected zones or too close to shore. Specific adverse effects of environmental and other specific effects will however not be evaluated. For instance it is not clear what significance the visual impacts and coast scenery will be and what restrictions

  7. The Impact of Coastal Terrain on Offshore Wind and Implications for Wind Energy

    Science.gov (United States)

    Strobach, Edward Justin

    The development of offshore wind energy is moving forward as one of several options for carbon-free energy generation along the populous US east coast. Accurate assessments of the wind resource are essential and can significantly lower financing costs that have been a barrier to development. Wind resource assessment in the Mid-Atlantic region is challenging since there are no long-term measurements of winds across the rotor span. Features of the coastal and inland terrain, such as such as the Appalachian mountains and the Chesapeake Bay, are known to lead to complex mesoscale wind regimes onshore, including low-level jets (LLJs), downslope winds and sea breezes. Little is known, however, about whether or how the inland physiography impacts the winds offshore. This research is based on the first comprehensive set of offshore wind observations in the Maryland Wind Energy Area gathered during a UMBC measurement campaign. The presentation will include a case study of a strong nocturnal LLJ that persisted for several hours before undergoing a rapid breakdown and loss of energy to smaller scales. Measurements from an onshore wind profiler and radiosondes, together with North American Regional Analysis (NARR) and a high resolution Weather Research and Forecast (WRF) model simulation, are used to untangle the forcing mechanisms on synoptic, regional and local scales that led to the jet and its collapse. The results suggest that the evolution of LLJs were impacted by a downslope wind from the Appalachians that propagated offshore riding atop a shallow near-surface boundary layer across the coastal plain. Baroclinic forcing from low sea surface temperatures (SSTs) due to coastal upwelling is also discussed. Smaller scale details of the LLJ breakdown are analyzed using a wave/mean flow/turbulence interaction approach. The case study illustrates several characteristics of low-level winds offshore that are important for wind energy, including LLJs, strong wind shear, turbulence

  8. Applicability of Synthetic Aperture Radar Wind Retrievals on Offshore Wind Resources Assessment in Hangzhou Bay, China

    Directory of Open Access Journals (Sweden)

    Rui Chang

    2014-05-01

    Full Text Available In view of the high cost and sparse spatial resolution of offshore meteorological observations, ocean winds retrieved from satellites are valuable in offshore wind resource assessment as a supplement to in situ measurements. This study examines satellite synthetic aperture radar (SAR images from ENVISAT advanced SAR (ASAR for mapping wind resources with high spatial resolution. Around 181 collected pairs of wind data from SAR wind maps and from 13 meteorological stations in Hangzhou Bay are compared. The statistical results comparing in situ wind speed and SAR-based wind speed show a standard deviation (SD of 1.99 m/s and correlation coefficient of R = 0.67. The model wind directions, which are used as input for the SAR wind speed retrieval, show a high correlation coefficient (R = 0.89 but a large standard deviation (SD = 42.3° compared to in situ observations. The Weibull probability density functions are compared at one meteorological station. The SAR-based results appear not to estimate the mean wind speed, Weibull scale and shape parameters and wind power density from the full in situ data set so well due to the lower number of satellite samples. Distributions calculated from the concurrent 81 SAR and in situ samples agree well.

  9. Developments of the offshore wind turbine wake model Fuga

    DEFF Research Database (Denmark)

    Ott, Søren; Nielsen, Morten

    features to Fuga and turn it into a useful tool for offshore wind farm developers. The new features consist in - Flexibility. Including the ability to cope with several types of turbines in the same project, thus making it possible to predict inter farm interactions. The graphical user interface has been...... from Horns Rev has been made in order to quantify the impact of non-stationarity of the wind direction. The results are generalized so as to account for the uncertainties imposed by a ten minute mean value trend as well as by the distance between turbines and the met mast. The old model has been......This is the final report of the project entitled Risø DTU Modelling Services carried out by DTU Wind Energy (formerly known as Risø National Laboratory) as part of the Carbon Trust's Offshore Wind Accelerator Stage 2 under a contract with Carbon Trust. The project is a follow-up to a Carbon Trust...

  10. On the Application of Fluid Power Transmission in Offshore Wind Turbines

    NARCIS (Netherlands)

    Diepeveen, N.F.B.

    2013-01-01

    Offshore wind energy is currently characterized by the high costs associated with installation and operation. Gearboxes in particular have been singled out as a key source of the high maintenance costs of offshore wind farms. For a given wind speed, the torque of the rotor increases cubically with

  11. Collection System Cable Routing and Wake Losses Optimization in Offshore Wind Farms

    NARCIS (Netherlands)

    Fragoso Rodrigues, S.M.; Bauer, P.; Bosman, P.A.N.; Pierik, J.

    2014-01-01

    Offshore wind farms with high installed capacities and located further from the shore are starting to be built by northern European countries. Furthermore, it is expected that by 2020, several dozens of large offshore wind farms will be built in the Baltic, Irish and North seas. These wind farms

  12. 76 FR 14681 - Commercial Leasing for Wind Power on the Outer Continental Shelf (OCS) Offshore Massachusetts...

    Science.gov (United States)

    2011-03-17

    ... Bureau of Ocean Energy Management, Regulation and Enforcement Commercial Leasing for Wind Power on the...: Request for Interest (RFI) in Commercial Wind Energy Leasing Offshore Massachusetts and Invitation for... Commercial Wind Energy Leasing Offshore Massachusetts and Invitation for Comments from Interested and...

  13. 75 FR 57271 - Creating an Offshore Wind Industry in the United States: A National Vision

    Science.gov (United States)

    2010-09-20

    ... of Energy Efficiency and Renewable Energy Creating an Offshore Wind Industry in the United States: A... Energy (DOE) Office of Energy Efficiency and Renewable Energy (EERE), Wind and Water Power Program, is planning a series of public events to exchange information on the development of offshore wind energy in...

  14. Combined Optimization for Offshore Wind Turbine Micro Siting

    DEFF Research Database (Denmark)

    Hou, Peng; Hu, Weihao; N. Soltani, Mohsen

    2017-01-01

    In order to minimize the wake loss, wind turbines (WT) should be separated with large intervening spaces. However, this will incur an increase in the capital expenditure on electrical systems and even in the operation and maintenance costs. In order to realize a cost-effective wind farm, an integ.......00% and increase the energy yields by 3.82% compared with the Norwegian centre for offshore wind energy (NORCOWE) reference wind farm layout. This is better than the traditional method which only achieves a 1.45% LPC reduction although it increases the energy yields by 3.95%.......In order to minimize the wake loss, wind turbines (WT) should be separated with large intervening spaces. However, this will incur an increase in the capital expenditure on electrical systems and even in the operation and maintenance costs. In order to realize a cost-effective wind farm......) algorithm is adopted to minimize the levelized production cost (LPC) of the wind farm. Simulation results are given for validating the proposed approach and comparison is made with results obtained using other methods. It is found that the proposed method can reduce the levelized production cost (LPC) by 5...

  15. Hydroacoustic registration of fish abundance of offshore wind farms. Horns Rev offshore wind farm. Annual report 2004.

    Energy Technology Data Exchange (ETDEWEB)

    Hvidt, C.B.; Bruenner, L.; Reier Knudsen, F.

    2005-05-15

    Elsam Engineering AS has approved the implementation of a project concerning the registration of fish communities in Horns Rev Offshore Wind Farm with use of hydroacoustic methods. In a joint effort, Bio/consult as, Carl Bro as and SIMRAD AS have monitored the fish communities at Horns Rev Offshore Wind Farm using a new hydroacoustic methodology. The new hydroacoustic technique combines the use of scientific sonar acoustics with GPS to determine the density, diversity and location of fish. The objectives of this project were to test the possibility of using hydroacoustic techniques as alternative methods to traditional techniques to assess the fish assemblage inhabiting offshore wind farms and to investigate the possible effect from the wind farm and hard bottom substrates (turbine foundations) on fish abundance. The field study was carried out October 9-10, 2004 and consisted of four horizontal hydroacoustic survey transects each covering impact and reference areas. Transects were surveyed in order to achieve identical impact and reference transect pairs concerning environment, topography and time correspondence. The hydroacoustic equipment consisted of a SIMRAD EK60/EY60 echo sounder with a split-beam transducer (Simrad ES 120-4x10) mounted on a pan and tilt unit, a transceiver, a laptop extended with a GPS-receiver and additional large external hard discs. The raw data files from EK60 were converted to echogram files suitable for the post processing application, Sonar5-Pro. The Sonar5-Pro software makes it possible to filter out echo detections from the surface and the bottom, as well as perform cross filter detection. The validity of the results using the hydroacoustic method is high due to the cross filtering and single target tracking technique. From the hydroacoustic results, no or very little effect from the wind farm or from hard bottom substrates was found on the fish densities at Horns Rev Wind Farm at the time of the survey. The execution of the field

  16. Using the PROSA Method in Offshore Wind Farm Location Problems

    Directory of Open Access Journals (Sweden)

    Paweł Ziemba

    2017-11-01

    Full Text Available Wind is the most used renewable energy source (RES in the European Union and Poland. Due to the legal changes in the scope of RES in Poland, there are plans to develop offshore wind farms at the expense of onshore ones. On the other hand, the success of an offshore wind farm is primarily determined by its location. Therefore, the aim of this study is to select offshore wind farm locations in Poland, based on sustainability assessment, which is an inherent aspect of RES decision-making issues. To accomplish the objectives of this research, PROSA (PROMETHEE for Sustainability Assessment method, a new multi-criteria method is proposed. Like PROMETHEE (Preference Ranking Organization METHod for Enrichment Evaluation, PROSA is transparent for decision makers and is easy to use; moreover, it provides the analytical tools available in PROMETHEE, i.e., the sensitivity and GAIA (Geometrical Analysis for Interactive Assistance analyses. However, PROSA is characterized by a lower degree of criteria compensation than PROMETHEE. Thus, it adheres in a higher degree to the strong sustainability paradigm. The study also compared the solutions of the decision problem obtained with the use of PROSA and PROMETHEE methods. The compared methods demonstrated a high concurrence of the recommended decision-making variant of location selection, from methodological and practical points of view. At the same time, the conducted research allowed to confirm that the PROSA method recommends more sustainable decision-making variants, and that the ranking it builds is less sensitive to changes in criteria weights. Therefore, it is more stable than the PROMETHEE-based ranking.

  17. Structural health and prognostics management for offshore wind turbines :

    Energy Technology Data Exchange (ETDEWEB)

    Myrent, Noah J.; Kusnick, Joshua F.; Barrett, Natalie C.; Adams, Douglas E.; Griffith, Daniel

    2013-04-01

    Operations and maintenance costs for offshore wind plants are significantly higher than the current costs for land-based (onshore) wind plants. One way to reduce these costs would be to implement a structural health and prognostic management (SHPM) system as part of a condition based maintenance paradigm with smart load management and utilize a state-based cost model to assess the economics associated with use of the SHPM system. To facilitate the development of such a system a multi-scale modeling approach developed in prior work is used to identify how the underlying physics of the system are affected by the presence of damage and faults, and how these changes manifest themselves in the operational response of a full turbine. This methodology was used to investigate two case studies: (1) the effects of rotor imbalance due to pitch error (aerodynamic imbalance) and mass imbalance and (2) disbond of the shear web; both on a 5-MW offshore wind turbine in the present report. Based on simulations of damage in the turbine model, the operational measurements that demonstrated the highest sensitivity to the damage/faults were the blade tip accelerations and local pitching moments for both imbalance and shear web disbond. The initial cost model provided a great deal of insight into the estimated savings in operations and maintenance costs due to the implementation of an effective SHPM system. The integration of the health monitoring information and O&M cost versus damage/fault severity information provides the initial steps to identify processes to reduce operations and maintenance costs for an offshore wind farm while increasing turbine availability, revenue, and overall profit.

  18. Stability analysis of offshore wind farm and marine current farm

    Science.gov (United States)

    Shawon, Mohammad Hasanuzzaman

    Renewable energy has been playing an important role to meet power demand and 'Green Energy' market is getting bigger platform all over the world in the last few years. Due to massive increase in the prices of fossil fuels along with global warming issues, energy harvesting from renewable energy sources has received considerable interest, nowadays, where extensive researches are going on to ensure optimum use of renewable sources. In order to meet the increasing demand of electricity and power, integration of renewable energy is getting highest priorities around the world. Wind is one of the most top growing renewable energy resources and wind power market penetration is expected to reach 3.35 percent by 2013 from its present market of about 240 GW. A wind energy system is the most environmental friendly, cost effective and safe among all renewable energy resources available. Another promising form of renewable energy is ocean energy which covers 70 % of the earth. Ocean energy can be tapped from waves, tides and thermal elements. Offshore Wind farm (OWF) has already become very popular for large scale wind power integration with the onshore grid. Recently, marine current farm (MCF) is also showing good potential to become mainstream energy sources and already successfully commissioned in United Kingdom. However, squirrel cage induction generator (SCIG) has the stability problem similar to synchronous generator especially during fault location to restore the electromagnetic torque. Series dynamic braking resistor (SDBR) has been known as a useful mean to stabilize fixed speed wind generator system. On the other hand, doubly fed induction generator (DFIG) has the capability of coupling the control of active and reactive power and to provide necessary reactive power demand during grid fault conditions. Series dynamic braking resistor (SDBR) can also be employed with DFIG to limit the rotor over current. An integration of wind and tidal energy represents a new

  19. Fundamentals for remote condition monitoring of offshore wind turbines

    DEFF Research Database (Denmark)

    McGugan, Malcolm; Larsen, Gunner Chr.; Sørensen, Bent F.

    necessary for the use of sensors as a structural health monitoring system for wind turbine blades. This includes creating knowledge that will allow sensor signals to be used for remotely identifying the presence and position of any damage, the damage type and severity, and a structural condition assessment...... of the wind turbine blades that can integrate with existing SCADA tools to improve management of large offshore wind farms, and optimise the manual inspection/maintenance effort. Various sensor types, which have previously been identified as technically (and economically) capable of detecting the early...... regimes. The application of sensors is addressed during a full-scale blade test and recommendations are made regarding improvement to the commercial blade certification process of test and inspection, sensor use for monitoring in-service structural response, and the need for dedicated research facilities...

  20. Selected Aspects Of Building, Operation And Environmental Impact Of Offshore Wind Power Electric Plants

    Directory of Open Access Journals (Sweden)

    Mroziński Adam

    2015-04-01

    Full Text Available This paper describes essence of work of offshore wind power electric plants and crucial aspects of their building and operating. Prospects for development of global, European and domestic markets of offshore wind power industry have been delineated. A comparative analysis of environmental impact of an offshore and land-based 2MW wind power electric plant has been performed by using LCA method and Ecoindex – 99 (Ekowskaźnik 99 modelling.

  1. Hierarchical Communication Network Architectures for Offshore Wind Power Farms

    Directory of Open Access Journals (Sweden)

    Mohamed A. Ahmed

    2014-05-01

    Full Text Available Nowadays, large-scale wind power farms (WPFs bring new challenges for both electric systems and communication networks. Communication networks are an essential part of WPFs because they provide real-time control and monitoring of wind turbines from a remote location (local control center. However, different wind turbine applications have different requirements in terms of data volume, latency, bandwidth, QoS, etc. This paper proposes a hierarchical communication network architecture that consist of a turbine area network (TAN, farm area network (FAN, and control area network (CAN for offshore WPFs. The two types of offshore WPFs studied are small-scale WPFs close to the grid and medium-scale WPFs far from the grid. The wind turbines are modelled based on the logical nodes (LN concepts of the IEC 61400-25 standard. To keep pace with current developments in wind turbine technology, the network design takes into account the extension of the LNs for both the wind turbine foundation and meteorological measurements. The proposed hierarchical communication network is based on Switched Ethernet. Servers at the control center are used to store and process the data received from the WPF. The network architecture is modelled and evaluated via OPNET. We investigated the end-to-end (ETE delay for different WPF applications. The results are validated by comparing the amount of generated sensing data with that of received traffic at servers. The network performance is evaluated, analyzed and discussed in view of end-to-end (ETE delay for different link bandwidths.

  2. A General Probabilistic Forecasting Framework for Offshore Wind Power Fluctuations

    Directory of Open Access Journals (Sweden)

    Henrik Madsen

    2012-03-01

    Full Text Available Accurate wind power forecasts highly contribute to the integration of wind power into power systems. The focus of the present study is on large-scale offshore wind farms and the complexity of generating accurate probabilistic forecasts of wind power fluctuations at time-scales of a few minutes. Such complexity is addressed from three perspectives: (i the modeling of a nonlinear and non-stationary stochastic process; (ii the practical implementation of the model we proposed; (iii the gap between working on synthetic data and real world observations. At time-scales of a few minutes, offshore fluctuations are characterized by highly volatile dynamics which are difficult to capture and predict. Due to the lack of adequate on-site meteorological observations to relate these dynamics to meteorological phenomena, we propose a general model formulation based on a statistical approach and historical wind power measurements only. We introduce an advanced Markov Chain Monte Carlo (MCMC estimation method to account for the different features observed in an empirical time series of wind power: autocorrelation, heteroscedasticity and regime-switching. The model we propose is an extension of Markov-Switching Autoregressive (MSAR models with Generalized AutoRegressive Conditional Heteroscedastic (GARCH errors in each regime to cope with the heteroscedasticity. Then, we analyze the predictive power of our model on a one-step ahead exercise of time series sampled over 10 min intervals. Its performances are compared to state-of-the-art models and highlight the interest of including a GARCH specification for density forecasts.

  3. Operation and control of a DC-grid offshore wind farm under DC transmission system faults

    DEFF Research Database (Denmark)

    Deng, Fujin; Chen, Zhe

    2013-01-01

    So far, all existing offshore wind farms have an ac collection system, and the collected power in the offshore wind farm is sent to an onshore ac grid through high-voltage ac (HVAC) or DC (HVDC) transmission lines. However, future of fshore wind farms may use dc also for power collection. Consequ......So far, all existing offshore wind farms have an ac collection system, and the collected power in the offshore wind farm is sent to an onshore ac grid through high-voltage ac (HVAC) or DC (HVDC) transmission lines. However, future of fshore wind farms may use dc also for power collection....... Consequently, the protection and control strategies of dc systems need to be established. This paper studies a dc-grid offshore wind farm, where the wind power collection system and power transmission system adopt dc technology. In this paper, the redundancy of the HVDC transmission system under faults...... is studied, and a fault ridethrough strategy for the dc-grid offshore wind farm is proposed. The proposed strategy can effectively minimize the impacts of the power transmission system disturbance on the offshore wind farm, and on the ac grid. A dc-grid offshore wind farm example is simulated with PSCAD...

  4. Review of Methodologies for Offshore Wind Resource Assessment in European Seas

    DEFF Research Database (Denmark)

    Sempreviva, Anna Maria; Barthelmie, Rebecca Jane; Pryor, Sara

    2008-01-01

    The wind resource offshore is generally larger than at geographically nearby onshore sites, which can offset the higher installation, operation and maintenance costs associated with offshore wind parks. Successful offshore wind energy development relies to some extent on accurate prediction of wind...... resources, but since installing and operating a meteorological mast in situ is expensive, prospective sites must be carefully evaluated. Accordingly, one can conceptualize the wind resource assessment process as a two-phase activity: (i) an evaluation of wind resources at the regional scale to locate...

  5. Lifetime Estimation of MMC for Offshore Wind Power HVDC Application

    DEFF Research Database (Denmark)

    Liu, Hui; Ma, Ke; Qin, Zian

    2016-01-01

    Due to a series of unique merits, Modular Multilevel Converters (MMCs) have been developing dramatically in the last decade. However in some applications like offshore power transmission the MMC modules are subjected to a variety of tough temperature profiles with adverse working condition, all...... of these could lead to thermomechanical fatigues in the components and joints of the power modules and thereby causing reliability challenge. This study focuses on the lifetime evaluation of MMC based on power cycling and thermal cycling considering the mission profiles in the High Voltage Direct Current (HVDC......) application for offshore wind power. The mission profiles as well as the topology of the MMC are first analyzed in order to better understand the loading characteristics of MMC. Then the power loss calculation along with the electro-thermal simulation is conducted to uncover the thermal loading of MMC...

  6. Lifetime Estimation of MMC for Offshore Wind Power HVDC Application

    DEFF Research Database (Denmark)

    Liu, Hui; Ma, Ke; Loh, Poh Chiang

    2014-01-01

    Due to a series of unique merits, Modular Multilevel Converters (MMCs) have been developing dramatically in the last decade. However in some applications like offshore power transmission the MMC modules are subjected to a variety of tough temperature profiles with adverse working condition, all...... of these could lead to thermo-mechanical fatigues in the components and joints of the power modules and thereby causing reliability challenge. This study focuses on the lifetime evaluation of MMC based on power cycling and thermal cycling considering the mission profiles in the High Voltage Direct Current (HVDC......) application for offshore wind power. The mission profiles as well as the topology of the MMC are first analyzed in order to better understand the loading profiles of MMC. Then the power loss calculation along with the electro-thermal simulation is conducted to uncover the thermal loading of MMC. At last...

  7. 3. International Workshop on Transmission Networks for Offshore Wind Farms. Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    Ackermann, T. (ed.)

    2002-07-01

    The emphasis is on both theoretical discussions and on practical applications. After almost a decade with mainly demonstration projects in the area of offshore wind power, this year will see the first large commercial offshore wind projects with more than 50 MW installed capacity and more and more larger projects are scheduled for the coming years. Also more and more energy policy makers, electric utilities as well as the media recognize the enormous potential of offshore wind power as a large-scale sustainable energy source. The development in this area results in new ideas, questions and research proposals. Such a new topic is, hydrogen production using offshore wind farms.

  8. Improved Offshore Wind Resource Assessment in Global Climate Stabilization Scenarios

    Energy Technology Data Exchange (ETDEWEB)

    Arent, D.; Sullivan, P.; Heimiller, D.; Lopez, A.; Eurek, K.; Badger, J.; Jorgensen, H. E.; Kelly, M.; Clarke, L.; Luckow, P.

    2012-10-01

    This paper introduces a technique for digesting geospatial wind-speed data into areally defined -- country-level, in this case -- wind resource supply curves. We combined gridded wind-vector data for ocean areas with bathymetry maps, country exclusive economic zones, wind turbine power curves, and other datasets and relevant parameters to build supply curves that estimate a country's offshore wind resource defined by resource quality, depth, and distance-from-shore. We include a single set of supply curves -- for a particular assumption set -- and study some implications of including it in a global energy model. We also discuss the importance of downscaling gridded wind vector data to capturing the full resource potential, especially over land areas with complex terrain. This paper includes motivation and background for a statistical downscaling methodology to account for terrain effects with a low computational burden. Finally, we use this forum to sketch a framework for building synthetic electric networks to estimate transmission accessibility of renewable resource sites in remote areas.

  9. Prospects for generating electricity by large onshore and offshore wind farms

    Science.gov (United States)

    Volker, Patrick J. H.; Hahmann, Andrea N.; Badger, Jake; Jørgensen, Hans E.

    2017-03-01

    The decarbonisation of energy sources requires additional investments in renewable technologies, including the installation of onshore and offshore wind farms. For wind energy to remain competitive, wind farms must continue to provide low-cost power even when covering larger areas. Inside very large wind farms, winds can decrease considerably from their free-stream values to a point where an equilibrium wind speed is reached. The magnitude of this equilibrium wind speed is primarily dependent on the balance between turbine drag force and the downward momentum influx from above the wind farm. We have simulated for neutral atmospheric conditions, the wind speed field inside different wind farms that range from small (25 km2) to very large (105 km2) in three regions with distinct wind speed and roughness conditions. Our results show that the power density of very large wind farms depends on the local free-stream wind speed, the surface characteristics, and the turbine density. In onshore regions with moderate winds the power density of very large wind farms reaches 1 W m-2, whereas in offshore regions with very strong winds it exceeds 3 W m-2. Despite a relatively low power density, onshore regions with moderate winds offer potential locations for very large wind farms. In offshore regions, clusters of smaller wind farms are generally preferable; under very strong winds also very large offshore wind farms become efficient.

  10. The influence of waves on the offshore wind resource

    Energy Technology Data Exchange (ETDEWEB)

    Lange, B. [Risoe National Lab., Roskilde (Denmark); Hoejstrup, J. [NEG Micon, Randers (Denmark)

    1999-03-01

    With the growing interest in offshore wind resources, it has become increasingly important to establish and refine models for the interaction between wind and waves in order to obtain accurate models for the sea surface roughness. The simple Charnock relation that has been applied for open sea conditions does not work well in the shallow water near-coastal areas that are important for offshore wind energy. A model for the surface roughness of the sea has been developed based on this concept, using an expression for the Charnock constant as a function of wave age, and then relating the wave `age` to the distance to the nearest upwind coastline. The data used in developing these models originated partly from analysis of data from the Vindeby site, partly from previously published results. The scatter in the data material was considerable and consequently there is a need to test these models further by analysing data from sites exhibiting varying distances to the coast. Results from such analysis of recent data are presented for sites with distances to the coast varying from 10 km to several hundreds of km. The model shows a good agreement also with this data. (au)

  11. High-Resolution Wind Measurements for Offshore Wind Energy Development

    Science.gov (United States)

    Nghiem, Son V.; Neumann, Gregory

    2011-01-01

    A mathematical transform, called the Rosette Transform, together with a new method, called the Dense Sampling Method, have been developed. The Rosette Transform is invented to apply to both the mean part and the fluctuating part of a targeted radar signature using the Dense Sampling Method to construct the data in a high-resolution grid at 1-km posting for wind measurements over water surfaces such as oceans or lakes.

  12. Structural health and prognostics management for offshore wind turbines :

    Energy Technology Data Exchange (ETDEWEB)

    Griffith, Daniel; Resor, Brian Ray; White, Jonathan Randall; Paquette, Joshua A.; Yoder, Nathanael C.

    2012-12-01

    Operations and maintenance costs for offshore wind plants are expected to be significantly higher than the current costs for onshore plants. One way in which these costs may be able to be reduced is through the use of a structural health and prognostic management system as part of a condition based maintenance paradigm with smart load management. To facilitate the creation of such a system a multiscale modeling approach has been developed to identify how the underlying physics of the system are affected by the presence of damage and how these changes manifest themselves in the operational response of a full turbine. The developed methodology was used to investigate the effects of a candidate blade damage feature, a trailing edge disbond, on a 5-MW offshore wind turbine and the measurements that demonstrated the highest sensitivity to the damage were the local pitching moments around the disbond. The multiscale method demonstrated that these changes were caused by a local decrease in the blades torsional stiffness due to the disbond, which also resulted in changes in the blades local strain field. Full turbine simulations were also used to demonstrate that derating the turbine power by as little as 5% could extend the fatigue life of a blade by as much as a factor of 3. The integration of the health monitoring information, conceptual repair cost versus damage size information, and this load management methodology provides an initial roadmap for reducing operations and maintenance costs for offshore wind farms while increasing turbine availability and overall profit.

  13. The Impact of Future Offshore Wind Farms on Wind Power Generation in Great Britain

    Directory of Open Access Journals (Sweden)

    Daniel R. Drew

    2015-03-01

    Full Text Available In the coming years the geographical distribution of wind farms in Great Britain is expected to change significantly. Following the development of the “round 3” wind zones (circa 2025, most of the installed capacity will be located in large offshore wind farms. However, the impact of this change in wind-farm distribution on the characteristics of national wind generation is largely unknown. This study uses a 34-year reanalysis dataset (Modern-Era Retrospective Analysis for Research and Applications (MERRA from National Aeronautics and Space Administration, Global Modeling and Assimilation Office (NASA-GMAO to produce a synthetic hourly time series of GB-aggregated wind generation based on: (1 the “current” wind farm distribution; and (2 a “future” wind farm distribution scenario. The derived data are used to estimate a climatology of extreme wind power events in Great Britain for each wind farm distribution. The impact of the changing wind farm distribution on the wind-power statistics is significant. The annual mean capacity factor increased from 32.7% for the current wind farm distribution to 39.7% for the future distribution. In addition, there are fewer periods of prolonged low generation and more periods of prolonged high generation. Finally, the frequency and magnitude of ramping in the nationally aggregated capacity factor remains largely unchanged. However, due to the increased capacity of the future distribution, in terms of power output, the magnitude of the ramping increases by a factor of 5.

  14. The Dynamic Stiffness of Surface Footings for Offshore Wind Turbines

    DEFF Research Database (Denmark)

    Vahdatirad, Mohammadjavad; Andersen, Lars; Clausen, Johan

    2011-01-01

    This study concerns the dynamic stiffness of foundations for large offshore wind turbines. Especially, the purpose of the analysis is to quantify the uncertainties related to the first natural frequency of a turbine supported by a surface footing on layered soil. The dynamic properties...... due to sediment transportation. Further, the stiffness and density of the materials within a single layer is subject to uncertainties. This leads to uncertainties of the dynamic stiffness of the foundation and therefore the natural frequencies. The aim of the study is to quantify the level...

  15. HTS technology - Generating the future of offshore wind power

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, Jens

    2010-09-15

    Superconductive generator design is going to become a real competitive alternative in the future. In general, superconductor design is the most competitive out of Direct Drive Systems and best fulfils the needs of the upcoming market - especially in the offshore market, where WECs with higher nominal power up to 10MW are required. Low weight, high reliability and the very good grid behaviour are the main advantages of the superconductor generator design and will lead to lower costs. The other systems are restricted to a smaller energy output range and / or onshore wind power production business.

  16. The effects of meshed offshore grids on offshore wind investment – a real options analysis

    DEFF Research Database (Denmark)

    Schröder, Sascha Thorsten; Kitzing, Lena

    farm’s IRR can increase by up to 33% in the analysed (fictive) cases when connected to four neighbouring countries. Contrarily, in case of nodal pricing, the wind farm will have to cope with IRRs that are up to 15% lower when connected to more than one country. These effects can either hamper adequate...... investment or lead to windfall profits, if the level of support were not adjusted according to the choice of regulatory regime. This should therefore be considered when designing the regulatory regime and level of support in the offshore grid in order to maintain an effective and efficient development...

  17. The effects of meshed offshore grids on offshore wind investment – a real options analysis

    DEFF Research Database (Denmark)

    Schröder, Sascha Thorsten; Kitzing, Lena

    2012-01-01

    farm’s IRR can increase by up to 33% in the analysed (fictive) cases when connected to four neighbouring countries. Contrarily, in case of nodal pricing, the wind farm will have to cope with IRRs that are up to 15% lower when connected to more than one country. These effects can either hamper adequate...... investment or lead to windfall profits, if the level of support were not adjusted according to the choice of regulatory regime. This should therefore be considered when designing the regulatory regime and level of support in the offshore grid in order to maintain an effective and efficient development...

  18. Definition of a 5-MW Reference Wind Turbine for Offshore System Development

    Energy Technology Data Exchange (ETDEWEB)

    Jonkman, J.; Butterfield, S.; Musial, W.; Scott, G.

    2009-02-01

    This report describes a three-bladed, upwind, variable-speed, variable blade-pitch-to-feather-controlled multimegawatt wind turbine model developed by NREL to support concept studies aimed at assessing offshore wind technology.

  19. Offshore Wind Energy: Wind and Sea Surface Temperature from Satellite Observations

    DEFF Research Database (Denmark)

    Karagali, Ioanna

    available wind speed and direction observations over the ocean and for a better understanding of the marine atmospheric boundary layer (MABL). The sea surface temperature (SST) has a direct impact on the marine atmospheric boundary layer, as the top few meters of the ocean have the same heat capacity...... as the entire atmosphere above. Under conditions of light winds and strong solar insolation, warming of the upper oceanic layer may occur. In this PhD study, remote sensing from satellites is used to obtain information for the near-surface ocean wind and the sea surface temperature over the North Sea...... and the Baltic Sea. The aim is to evaluate their potential use and demonstrate their applicability within the context of offshore wind energy; for the quantication of the wind resources and for the identication of diurnal warming of the sea surface temperature. Space-borne observations of wind are obtained from...

  20. Modelling of offshore wind turbine wakes with the wind farm program FLaP

    DEFF Research Database (Denmark)

    Lange, B.; Waldl, H.P.; Guerrero, A.G.

    2003-01-01

    behind one rotor. Here an approach based on the simplified Reynolds equation with eddy viscosity closure is chosen. The single-wakemodel is combined with a model for the vertical wind speed profile and a wind farm model, which takes care of the interaction of all wakes in a wind farm. The wake model has...... intensities in the wake are compared for single-, double- and quintuple-wake cases with different mean wind speed, turbulence intensity and atmospheric stability. It is found that within the measurement uncertainties the results of the wake model compare well with the measurements for the most important...... ambient conditions. The effect of the low turbulence intensity offshore on the wake development is modelled well for Vindeby wind farm. Deviations are found when atmospheric stability deviates from near-neutral conditions. For stable atmospheric conditions both the free vertical wind speed profile...

  1. Importance of thermal effects and sea surface roughness for offshore wind resource assessment

    DEFF Research Database (Denmark)

    Lange, B.; Larsen, Søren Ejling; Højstrup, Jørgen

    2004-01-01

    The economic feasibility of offshore wind power utilisation depends on the favourable wind conditions offshore as compared to sites on land. The higher wind speeds have to compensate the additional cost of offshore developments. However, not only the mean wind speed is different, but the whole flow......-Obukhov theory, a simple correction method to account for this effect has been developed and is tested in the same way. The models for the estimation of the sea surface roughness were found to lead only to small differences. For the purpose of wind resource assessment, even the assumption of a constant roughness...

  2. Load calculation methods for offshore wind turbine foundations

    DEFF Research Database (Denmark)

    Passon, Patrik; Branner, Kim

    2014-01-01

    is given to jacket-type foundations, the methods are considered applicable for other bottom-mounted foundation types as well. All load calculation methods are applied and evaluated for an exemplarily fatigue design scenario from the perspective of an FD in order to establish more confidence......Calculation of design loads for offshore wind turbine (OWT) foundations is typically performed in a joint effort between wind turbine manufactures and foundation designers (FDs). Ideally, both parties would apply the same fully integrated design tool and model for that purpose. However...... turbine manufacturer provides the FD with dynamic responses obtained from aeroelastic simulations at a predefined interface. These responses are subsequently expanded to the corresponding dynamic responses in all structural parts of the foundation. In this article, a novel load calculation method...

  3. Review report 2004. The Danish offshore wind farm demonstration project: Horns Rev and Nysted offshore wind farms. Environmental impact assessment and monitoring

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2005-10-15

    The present review report presents the two wind farms Horns Rev and Nysted with regard to environmental characteristics and the results of the environmental studies carried out in connection with the Environmental Impact Assessment (EIA) and the baseline and monitoring programmes at the two sites. The descriptions of the programmes are based on extracts from the individual annual reports. Detailed information on method, programmes and conclusions can be found in these reports (see Appendix 1). This review report is divided into two parts. The first part contains a description of the potential environmental impacts of offshore wind farms and the potentially affected part of the environment. The second part includes a description of Horns Rev and Nysted Offshore Wind Farm and the environmental studies carried out here until the end of 2003. Appendix I is a list of the literature published on the studies carried out at Horns Rev and Nysted Offshore Wind Farm. Appendix II is a list of some of the literature relevant to the demonstration projects but not directly related to the projects. The offshore wind farm situated in the Roedsand area is officially denoted Nysted Offshore Wind Farm, and in the present report the denotation 'Nysted' will be used as well when referring to Nysted Offshore Wind Farm. The denotation Roedsand will be used when referring to the actual area Roedsand. (au)

  4. The use of low frequency AC for offshore wind power

    Energy Technology Data Exchange (ETDEWEB)

    Schuette, T.; Stroem, M.; Gustavsson, Bo [Balfour Beatty Rail AB, Vaesteraas (Sweden)

    2001-07-01

    Low frequency AC, that means AC with a frequency well below the usual frequencies 50 or 60 Hz, has today its main use in single phase AC electrified railways in a number of European countries (16 2/3 Hz), USA (25 Hz) and Costa Rica (20 Hz). Offshore wind power is well suited to 'join the club' as low frequency AC has a number of advantages for that use: Low frequency AC better fits the low revolution frequency of wind power rotors. This can either be used for reduction of pole number for direct generation machines or for a reduction of the gear ratio for conventional machines, resulting in simpler, lighter and more reliable gearboxes. Low frequency AC gives rise to lower charging current/reactive power production, which restricts the maximum cable length for 50 - 60 Hz heavily due to the high specific capacitance of power cables. For low frequency AC, cables longer than 100 km are possible, which is necessary for many future offshore wind power sites. Low frequency AC enables for the use of (air insulated) transmission lines at loads well above their characteristic power, often up to their thermal maximum load. This means that weak 50 or 60 Hz lines between the shore and consumers or stronger parts of a national grid can transfer more power when operated with low frequency AC. On all aspects of low frequency AC, profound knowledge has been accumulated the last century in the railway sector and can be made available for wind power.

  5. Can Weather Radars Help Monitoring and Forecasting Wind Power Fluctuations at Large Offshore Wind Farms?

    DEFF Research Database (Denmark)

    Trombe, Pierre-Julien; Pinson, Pierre; Madsen, Henrik

    2011-01-01

    The substantial impact of wind power fluctuations at large offshore wind farms calls for the development of dedicated monitoring and prediction approaches. Based on recent findings, a Local Area Weather Radar (LAWR) was installed at Horns Rev with the aim of improving predictability, controlability...... and potentially maintenance planning. Additional images are available from a Doppler radar covering the same area. The parallel analysis of rain events detection and of regime sequences in wind (and power) fluctuations demonstrates the interest of employing weather radars for a better operation and management...

  6. IRONLESS PERMANENT MAGNET GENERATORS FOR DIRECT-DRIVEN OFFSHORE WIND TURBINES

    OpenAIRE

    Zhaoqiang, Zhang

    2015-01-01

    Since the beginning of this century, the offshore wind power industry has witnessed fast development, as the result of the increasing awareness of climate change and the need for diversifying power supply. Offshore has vast area available with high wind speed, which is an ideal place for large-scale wind power exploitation. However, these advantages come with technological challenges. One of the key challenges is to develop high-power cost-effective wind turbines with high r...

  7. Variable Torque Control of Offshore Wind Turbine on Spar Floating Platform Using Advanced RBF Neural Network

    OpenAIRE

    Lei Wang; Shan Zuo; Y. D. Song; Zheng Zhou

    2014-01-01

    Offshore floating wind turbine (OFWT) has been a challenging research spot because of the high-quality wind power and complex load environment. This paper focuses on the research of variable torque control of offshore wind turbine on Spar floating platform. The control objective in below-rated wind speed region is to optimize the output power by tracking the optimal tip-speed ratio and ideal power curve. Aiming at the external disturbances and nonlinear uncertain dynamic systems of OFWT becau...

  8. The Impact of Offshore Wind Turbines on Underwater Ambient Noise Levels

    OpenAIRE

    Glegg, Stewart

    2015-01-01

    The underwater sound levels generated by offshore wind turbine farms is a concern because of the possible environmental impact on marine mammals. This paper will consider how sound generated by a wind turbine is transmitted into a shallow water channel. It is shown that the underwater sound levels can be calculated for a typical offshore wind turbine by using the theory of Chapman and Ward (1990) combined with aeroacoustic models of trailing edge noise on the wind turbine blades. A procedure ...

  9. Fully vs. Sequentially Coupled Loads Analysis of Offshore Wind Turbines

    Energy Technology Data Exchange (ETDEWEB)

    Damiani, Rick; Wendt, Fabian; Musial, Walter; Finucane, Z.; Hulliger, L.; Chilka, S.; Dolan, D.; Cushing, J.; O' Connell, D.; Falk, S.

    2017-06-19

    The design and analysis methods for offshore wind turbines must consider the aerodynamic and hydrodynamic loads and response of the entire system (turbine, tower, substructure, and foundation) coupled to the turbine control system dynamics. Whereas a fully coupled (turbine and support structure) modeling approach is more rigorous, intellectual property concerns can preclude this approach. In fact, turbine control system algorithms and turbine properties are strictly guarded and often not shared. In many cases, a partially coupled analysis using separate tools and an exchange of reduced sets of data via sequential coupling may be necessary. In the sequentially coupled approach, the turbine and substructure designers will independently determine and exchange an abridged model of their respective subsystems to be used in their partners' dynamic simulations. Although the ability to achieve design optimization is sacrificed to some degree with a sequentially coupled analysis method, the central question here is whether this approach can deliver the required safety and how the differences in the results from the fully coupled method could affect the design. This work summarizes the scope and preliminary results of a study conducted for the Bureau of Safety and Environmental Enforcement aimed at quantifying differences between these approaches through aero-hydro-servo-elastic simulations of two offshore wind turbines on a monopile and jacket substructure.

  10. Regulating Future Offshore Grids: Economic Impact Analysis on Wind Parks and Transmission System Operators

    DEFF Research Database (Denmark)

    Kitzing, Lena; Schröder, Sascha Thorsten

    The increasing development of offshore wind parks in the European offshore territory may lead to meshed offshore grids in which each wind park might be connected to several countries. Such offshore grids could be subject to various regulatory regimes, depending on the degree of cooperation between...... the respective countries. This study focuses on how investors in wind parks and transmission systems are affected by the choice of regulatory regime in offshore grids with one to four countries connected. In order to capture the uncertainties related to the exposure to market prices as well as risks related...... to line failures, we develop a stochastic model for an exemplary wind park and offshore grid. This yields the real option values of operational flexibility from additional connections. Simulation results show that the choice of regulatory regime, including market access and pricing rules, can have...

  11. Probabilistic Calibration of Fatigue Design Factors for Offshore Wind Turbine Support Structures

    DEFF Research Database (Denmark)

    Ramirez, José Rangel; Sørensen, John Dalsgaard

    2010-01-01

    for the considered offshore wind turbines in such a way that the specific uncertainties for the fatigue life are accounted in a rational manner. Similar approaches have been used for offshore oil & gas sub-structures, but the required reliability level for offshore wind turbines is generally lower and the fatigue......This paper describes a reliability-based approach to determine fatigue design factors (FDF) for offshore wind turbine support structures made of steel. The FDF values are calibrated to a specific reliability level and linked to a specific inspection and maintenance (I&M) strategy used...

  12. A CFD model of the wake of an offshore wind farm: Using a prescribed wake inflow

    DEFF Research Database (Denmark)

    Réthoré, P.-E.; Bechmann, Andreas; Sørensen, Niels N.

    2007-01-01

      An CFD model of the wake of an offshore wind farm, expanding existing measurements is proposed. The method is based on solving the Navier Stokes equation in a large domain downstream an offshore wind farm. The inflow of the domain is estimated using existing met mast measurements from both free...

  13. Large-Scale Offshore Wind Power in the United States: Executive Summary

    Energy Technology Data Exchange (ETDEWEB)

    Musial, W.; Ram, B.

    2010-09-01

    This document provides a summary of a 236-page NREL report that provides a broad understanding of today's offshore wind industry, the offshore wind resource, and the associated technology challenges, economics, permitting procedures, and potential risks and benefits.

  14. OC3 -- Benchmark Exercise of Aero-Elastic Offshore Wind Turbine Codes: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Passon, P.; Kuhn, M.; Butterfield, S.; Jonkman, J.; Camp, T.; Larsen, T. J.

    2007-08-01

    This paper introduces the work content and status of the first international investigation and verification of aero-elastic codes for offshore wind turbines as performed by the "Offshore Code Comparison Collaboration" (OC3) within the "IEA Wind Annex XXIII -- Subtask 2".

  15. An economic assessment of tropical cyclone risk on offshore wind farms

    DEFF Research Database (Denmark)

    Hong, Lixuan; Möller, Bernd

    2012-01-01

    and cost and setting design parameters for offshore wind turbines are then discussed. The impact of tropical cyclones on offshore wind farms likes a double-edged sword, which might be advantageous for some regions in terms of increasing full-loaded hours of turbines, but also disadvantageous for others due...

  16. O&M Modeling of Offshore Wind Farms - State of the Art and Future Developments

    DEFF Research Database (Denmark)

    Asgarpour, Masoud; Sørensen, John Dalsgaard

    2016-01-01

    In this paper the state of the art in O&M models for O&M cost estimation of offshore wind farms is discussed and then, a case study for O&M cost estimation of an 800 MW reference offshore wind farm is given. Moreover, a framework for an ideal O&M strategy optimizer to achieve the maximum possible...

  17. From laggard to leader: Explaining offshore wind developments in the UK

    NARCIS (Netherlands)

    Kern, Florian; Smith, Adrian; Shaw, Chris; Raven, Rob; Verhees, Bram

    2014-01-01

    Offshore wind technology has recently undergone rapid deployment in the UK. And yet, up until recently, the UK was considered a laggard in terms of deploying renewable energy. How can this burst of offshore wind activity be explained? An economic analysis would seek signs for newfound

  18. A decision support system for assessing offshore wind energy potential in the North Sea

    NARCIS (Netherlands)

    Schillings, Ch.; Wanderer, T.; Cameron, L.; Wal, van der J.T.; Jacquemin, J.; Veum, K.

    2012-01-01

    Offshore wind energy (OWE) in the North Sea has the potential to meet large share of Europe’s future electricity demand. To deploy offshore wind parks in a rational way, the overall OWE potential has to be realistically determined. This has to be done on an international, cross-border level and by

  19. Market and regulatory aspects of trans-national offshore electricity networks for wind power interconnection

    NARCIS (Netherlands)

    Roggenkamp, Martha M.; Hendriks, Ralph L.; Ummels, Bart C.; Kling, Wil L.

    Subsea cable connections are an essential part of offshore wind power projects. Apart from direct connections between an offshore wind park to the national grid, several alternatives can be envisaged, including the connection to interconnectors between countries or direct connection to a country

  20. Taming hurricanes with arrays of offshore wind turbines

    Science.gov (United States)

    Jacobson, Mark Z.; Archer, Cristina L.; Kempton, Willett

    2014-03-01

    Hurricanes are causing increasing damage to many coastal regions worldwide. Offshore wind turbines can provide substantial clean electricity year-round, but can they also mitigate hurricane damage while avoiding damage to themselves? This study uses an advanced climate-weather computer model that correctly treats the energy extraction of wind turbines to examine this question. It finds that large turbine arrays (300+ GW installed capacity) may diminish peak near-surface hurricane wind speeds by 25-41 m s-1 (56-92 mph) and storm surge by 6-79%. Benefits occur whether turbine arrays are placed immediately upstream of a city or along an expanse of coastline. The reduction in wind speed due to large arrays increases the probability of survival of even present turbine designs. The net cost of turbine arrays (capital plus operation cost less cost reduction from electricity generation and from health, climate, and hurricane damage avoidance) is estimated to be less than today’s fossil fuel electricity generation net cost in these regions and less than the net cost of sea walls used solely to avoid storm surge damage.

  1. High Level Environmental Screening Study for Offshore Wind Farm Developments – Marine Habitats and Species Project

    OpenAIRE

    Hiscock, K; Tyler-Walters, H.; Jones, H.

    2002-01-01

    High level environmental screening study for offshore wind farm developments – marine habitats and species \\ud This report provides an awareness of the environmental issues related to marine habitats and species for developers and regulators of offshore wind farms. \\ud The information is also relevant to other offshore renewable energy developments. \\ud The marine habitats and species considered are those associated with the seabed, seabirds, and sea mammals. The report concludes that the fol...

  2. Multi-hazard response analysis of a 5MW offshore wind turbine

    DEFF Research Database (Denmark)

    Katsanos, Evangelos; Sanz, A. Arrospide; Georgakis, Christos T.

    2017-01-01

    Wind energy has already dominant role on the scene of the clean energy production. Well-promising markets, like China, India, Korea and Latin America are the fields of expansion for new wind turbines mainly installed in offshore environment, where wind, wave and earthquake loads threat the struct......Wind energy has already dominant role on the scene of the clean energy production. Well-promising markets, like China, India, Korea and Latin America are the fields of expansion for new wind turbines mainly installed in offshore environment, where wind, wave and earthquake loads threat...... the structural integrity and reliability of these energy infrastructures. Along these lines, a multi-hazard environment was considered herein and the structural performance of a 5 MW offshore wind turbine was assessed through time domain analysis. A fully integrated model of the offshore structure consisting...

  3. Planners to the rescue: spatial planning facilitating the development of offshore wind energy.

    Science.gov (United States)

    Jay, Stephen

    2010-04-01

    The development of offshore wind energy has started to take place surprisingly quickly, especially in North European waters. This has taken the wind energy industry out of the territory of planning systems that usually govern the siting of wind farms on land, and into the world of departmental, sectoral regulation of marine activities. Although this has favoured the expansion of offshore wind energy in some respects, evidence suggests that the practice and principles of spatial planning can make an important contribution to the proper consideration of proposals for offshore wind arrays. This is especially so when a strategic planning process is put in place for marine areas, in which offshore wind is treated as part of the overall configuration of marine interests, so that adjustments can be made in the interests of wind energy. The current process of marine planning in the Netherlands is described as an illustration of this. (c) 2009 Elsevier Ltd. All rights reserved.

  4. Basic controller tuning for large offshore wind turbines

    Directory of Open Access Journals (Sweden)

    K. O. Merz

    2016-09-01

    Full Text Available When a wind turbine operates above the rated wind speed, the blade pitch may be governed by a basic single-input–single-output PI controller, with the shaft speed as input. The performance of the wind turbine depends upon the tuning of the gains and filters of this controller. Rules of thumb, based upon pole placement, with a rigid model of the rotor, are inadequate for tuning the controller of large, flexible, offshore wind turbines. It is shown that the appropriate controller tuning is highly dependent upon the characteristics of the aeroelastic model: no single reference controller can be defined for use with all models. As an example, the ubiquitous National Renewable Energy Laboratory (NREL 5 MW wind turbine controller is unstable when paired with a fully flexible aeroelastic model. A methodical search is conducted, in order to find models with a minimum number of degrees of freedom, which can be used to tune the controller for a fully flexible aeroelastic model; this can be accomplished with a model containing 16–20 states. Transient aerodynamic effects, representing rotor-average properties, account for five of these states. A simple method is proposed to reduce the full transient aerodynamic model, and the associated turbulent wind spectra, to the rotor average. Ocean waves are also an important source of loading; it is recommended that the shaft speed signal be filtered such that wave-driven tower side-to-side vibrations do not appear in the PI controller output. An updated tuning for the NREL 5 MW controller is developed using a Pareto front technique. This fixes the instability and gives good performance with fully flexible aeroelastic models.

  5. Wind and Wave Disturbances Compensation to Floating Offshore Wind Turbine Using Improved Individual Pitch Control Based on Fuzzy Control Strategy

    OpenAIRE

    Feng Yang; Qing-wang Song; Lei Wang; Shan Zuo; Sheng-shan Li

    2014-01-01

    Due to the rich and high quality of offshore wind resources, floating offshore wind turbine (FOWT) arouses the attentions of many researchers. But on a floating platform, the wave and wind induced loads can significantly affect power regulation and vibration of the structure. Therefore, reducing these loads becomes a challenging part of the design of the floating system. To better alleviate these fatigue loads, a control system making compensations to these disturbances is proposed. In this p...

  6. Floating Offshore Wind in Hawaii: Potential for Jobs and Economic Impacts from Three Future Scenarios

    Energy Technology Data Exchange (ETDEWEB)

    Jimenez, Tony; Keyser, David; Tegen, Suzanne

    2016-04-18

    Construction of the first offshore wind power plant in the United States began in 2015, off the coast of Rhode Island, using fixed platform structures that are appropriate for shallow seafloors, like those located off the East Coast and mid-Atlantic. However, floating platforms, which have yet to be deployed commercially, will likely need to be anchored to the deeper seafloor if deployed in Hawaiian waters. To analyze the employment and economic potential for floating offshore wind off Hawaii's coasts, the Bureau of Ocean Energy Management commissioned the National Renewable Energy Laboratory (NREL) to analyze two hypothetical deployment scenarios for Hawaii: 400 MW of offshore wind by 2050 and 800 MW of offshore wind by 2050. The results of this analysis can be used to better understand the general scale of economic opportunities that could result from offshore wind development.

  7. Towards a Joint Action Plan for Research and Development in the Offshore Wind Service Industry

    DEFF Research Database (Denmark)

    Andersen, Per Dannemand; Piirainen, Kalle A.; Clausen, Niels-Erik

    2015-01-01

    for offshore wind installations, and industry clusters based on OWS are emerging in regions around the North Sea. The JAP builds on a mapping (based on desk studies, patent analyses, and bibliometrics) of each of participating region’s existing capabilities, and on an overall strategic orientation and options......This paper presents a joint action plan (JAP) for research and development and innovation (RDI) in the offshore wind service industry in Denmark, Germany, Norway and the UK. Offshore wind servicing (OWS) is in this context defined as both assembly and installation of offshore wind farms as well...... for a innovation. The JAP is built on this foundation together with stakeholders from the four regions, comprising representatives from R&D and education, policy makers and offshore wind industry. Following the workshop, the ECOWindS consortium has been developing the proposed action plan further based...

  8. Modeling and Simulation of Offshore Wind Power Platform for 5 MW Baseline NREL Turbine.

    Science.gov (United States)

    Roni Sahroni, Taufik

    2015-01-01

    This paper presents the modeling and simulation of offshore wind power platform for oil and gas companies. Wind energy has become the fastest growing renewable energy in the world and major gains in terms of energy generation are achievable when turbines are moved offshore. The objective of this project is to propose new design of an offshore wind power platform. Offshore wind turbine (OWT) is composed of three main structures comprising the rotor/blades, the tower nacelle, and the supporting structure. The modeling analysis was focused on the nacelle and supporting structure. The completed final design was analyzed using finite element modeling tool ANSYS to obtain the structure's response towards loading conditions and to ensure it complies with guidelines laid out by classification authority Det Norske Veritas. As a result, a new model of the offshore wind power platform for 5 MW Baseline NREL turbine was proposed.

  9. Hydropower flexibility and transmission expansion to support integration of offshore wind

    DEFF Research Database (Denmark)

    Cutululis, Nicolaos Antonio; Farahmand, Hossein; Jaehnert, S.

    2016-01-01

    systems are a very good option for balancing the natural variability of wind power production, especially when installed offshore. The flexibility of hydropower systems allows power systems with a high share of RES to maintain stability. The analysis presented indicates that the value of hydropower......In 2013, offshore wind grew over 50%. This increase, concentrated in a relatively small geographical area, can lead to an increased variability of the power produced by offshore wind. The variability is one of the key issues, along transmission, in integrating offshore wind power. Hydro power...... of hydro generation can match the variability of offshore wind, allowing for larger shares of variable generation to be integrated in the power systems without decreasing its stability. The analysis includes two interrelated models, a market model and a flow-based model. The results show that hydropower...

  10. Response Analysis of a Spar-Type Floating Offshore Wind Turbine Under Atmospheric Icing Conditions

    DEFF Research Database (Denmark)

    Etemaddar, Mahmoud; Hansen, Martin Otto Laver; Moan, Torgeir

    2014-01-01

    One of the challenges for the development of wind energy in offshore cold-climate regions is atmospheric icing. This paper examines the effects of atmospheric icing on power production, overall performance, and extreme loads of a 5-MW spar-type floating offshore wind turbine during power producti......, as are the effects of atmospheric icing on land-based and offshore wind turbines.......One of the challenges for the development of wind energy in offshore cold-climate regions is atmospheric icing. This paper examines the effects of atmospheric icing on power production, overall performance, and extreme loads of a 5-MW spar-type floating offshore wind turbine during power production......, normal and emergency rotor shutdown, extreme gusts, and survival conditions. Atmospheric icing is simulated by using the ice accretion simulation code LEWICE. A CFD method is used to estimate the blade aerodynamic degradation due to icing. The effects of icing on one, two, or three blades are compared...

  11. Modeling and Simulation of Offshore Wind Power Platform for 5 MW Baseline NREL Turbine

    Directory of Open Access Journals (Sweden)

    Taufik Roni Sahroni

    2015-01-01

    Full Text Available This paper presents the modeling and simulation of offshore wind power platform for oil and gas companies. Wind energy has become the fastest growing renewable energy in the world and major gains in terms of energy generation are achievable when turbines are moved offshore. The objective of this project is to propose new design of an offshore wind power platform. Offshore wind turbine (OWT is composed of three main structures comprising the rotor/blades, the tower nacelle, and the supporting structure. The modeling analysis was focused on the nacelle and supporting structure. The completed final design was analyzed using finite element modeling tool ANSYS to obtain the structure’s response towards loading conditions and to ensure it complies with guidelines laid out by classification authority Det Norske Veritas. As a result, a new model of the offshore wind power platform for 5 MW Baseline NREL turbine was proposed.

  12. Modeling and Simulation of Offshore Wind Power Platform for 5 MW Baseline NREL Turbine

    Science.gov (United States)

    Roni Sahroni, Taufik

    2015-01-01

    This paper presents the modeling and simulation of offshore wind power platform for oil and gas companies. Wind energy has become the fastest growing renewable energy in the world and major gains in terms of energy generation are achievable when turbines are moved offshore. The objective of this project is to propose new design of an offshore wind power platform. Offshore wind turbine (OWT) is composed of three main structures comprising the rotor/blades, the tower nacelle, and the supporting structure. The modeling analysis was focused on the nacelle and supporting structure. The completed final design was analyzed using finite element modeling tool ANSYS to obtain the structure's response towards loading conditions and to ensure it complies with guidelines laid out by classification authority Det Norske Veritas. As a result, a new model of the offshore wind power platform for 5 MW Baseline NREL turbine was proposed. PMID:26550605

  13. How Expensive Is Expensive Enough? Opportunities for Cost Reductions in Offshore Wind Energy Logistics

    DEFF Research Database (Denmark)

    Poulsen, Thomas; Hasager, Charlotte Bay

    2016-01-01

    This paper reveals that logistics may conservatively amount to 18% of the levelized cost of energy for offshore wind farms. This is the key finding from an extensive case study carried out within the organization of the world’s leading offshore wind farm developer and operator. The case study aimed...... to, and produced, a number of possible opportunities for offshore wind cost reductions through logistics innovation; however, within the case study company, no company-wide logistics organization existed to focus horizontally on reducing logistics costs in general. Logistics was not well defined...... within the case study company, and a logistics strategy did not exist. With full life-cycle costs of offshore wind farms still high enough to present a political challenge within the European Union in terms of legislation to ensure offshore wind diffusion beyond 2020, our research presents logistics...

  14. Impacts of offshore wind energy turbines on marine bottom fauna

    Energy Technology Data Exchange (ETDEWEB)

    Schroeder, A. [Alfred Wegener Institute for Polar- and Marine Research, Bremerhaven (Germany)

    2007-07-01

    The foundations of offshore wind energy farms will cause alterations to the natural marine habitat of the North and Baltic Seas. The seabed in the proposed areas for offshore windfarms is mainly characterised by soft sediments ranging from medium sands to silt. The underwater structures themselves not only provide empty space for the settlement of hardbottom epifauna, which do not naturally occur in these areas, but they also alter the surrounding natural habitat. In the absence of actual wind farms in German waters, the research platform FINO 1 was used in the project BeoFINO to study biologic processes around the underwater structure leading to alterations of the natural bottom fauna. Shortly after installation, the surface was colonised by an epifauna consisting of few species, but reaching a high biomass. Mytilus edulis dominated in the upper depth zone, while lower reaches were dominated by the Amphipod Jassa spp. and Anthozoans (mainly Metridium senile). Changed current conditions around the structure lead to erosion and altered sediment composition with thick layers of empty shells on the surface. Natural soft bottom fauna is strongly reduced in the vicinity of the platform, while predators and scavengers profit from the additional food source provided by material falling from the platform. The export of lighter material like faeces is predicted to spread over larger areas. Dense aggregations of pelagic fish were observed around the platform, while some demersal species also live in niches of the structure. All results are combined in mathematical models in order to compare different locations and to calculate scenarios for wind farm effects in various habitats. (orig.)

  15. Artificial upwelling using offshore wind energy for mariculture applications

    Directory of Open Access Journals (Sweden)

    Álvaro Viúdez

    2016-09-01

    Full Text Available Offshore wind is proposed as an energy source to upwell nutrient-rich deep water to the ocean photic layers. A spar-buoy wind turbine with a rigid tube about 300 m long is proposed as a pipe to drive deep water up to the surface. The minimum energy required to uplift the water is the potential energy difference between surface waters inside and outside the pipe, which depends on the background density profile. The corresponding surface jump or hydraulic head, h, calculated for several analytical and experimental density profiles, is of the order of 10 cm. If the complete turbine power (of the order of several MW is used for raising the water (assuming a 100% pump efficiency, in a frictionless flow, very large water volumes, of the order of thousands of m3 s-1, will be transported to the photic layers. In a more realistic case, taking into account pipe friction in wide pipes, of the order of 10 m radius, and a power delivered to the fluid of 1 MW, the volume transport is still very large, about 500 m3 s-1. However, such a large amount of dense water could sink fast to aphotic layers due to vertical static instability (the fountain effect, ruining the enhancement of primary production. Hence, some ways to increase the turbulent entrainment and avoid the fountain effect are proposed. From the energetic viewpoint, artificial upwelling using offshore wind energy is a promising way to fertilize large open sea regions. This mariculture application is, however, severely subjected to atmosphere and ocean climatology, as well as to ecological dynamics. The general problem is multidisciplinary, and some important physical, engineering and ecological questions need to be seriously addressed to improve our confidence in the approach presented here.

  16. The construction of offshore wind power plants and geotechnical safety aspects; Der Bau von Offshore-Windkraftwerken und geotechnische Sicherheitsaspekte

    Energy Technology Data Exchange (ETDEWEB)

    Weber, Klaus; Hartwig, Udo [Ed. Zueblin AG, Stuttgart (Germany)

    2008-07-01

    With the development of the environmental political and energy-political targets with respect to the reduction of the CO{sub 2} emissions, offshore wind energy plants are a substantial key element. Thereby, the construction of offshore wind power plants represents a very large potential future market for the building industry. Thus, the foundation determines a substantial amount of the structural and economic risks. During the draft of the foundation, the predominantly horizontal and cyclic loads as well as the influence of the draft on the costs of logistics are the main criteria. In the case of the foundation of offshore wind power plants, risk and security are to be evaluated differently in comparison to usual geotechnical buildings. Offshore wind parks need the installation of a multiplicity of machine foundations under most difficult conditions. An adequate wealth of experience now is not present, and must be developed in the next years by systematic accompanying investigations. The well-known computer models and proof procedures only can be used conditioned. In the case of offshore wind energy plants, the foundation and the complex interaction between the construction of the foundation and the building ground should be focussed in comparison to the mechanical engineering.

  17. Damping Estimation of a Prototype Bucket Foundation for Offshore Wind Turbines Identified by Full Scale Testing

    DEFF Research Database (Denmark)

    Damgaard, Mads; Ibsen, Lars Bo; Andersen, Lars Vabbersgaard

    2013-01-01

    Wave loading misaligned with wind turbulence often introduces large fatigue loads on offshore wind turbine structures. In this particular case, the structure is sensitive to resonant excitation acting out of the wind direction due to a small aerodynamic damping contribution in the cross-wind dire...

  18. Mapping Offshore Winds Around Iceland Using Satellite Synthetic Aperture Radar and Mesoscale Model Simulations

    DEFF Research Database (Denmark)

    Hasager, Charlotte Bay; Badger, Merete; Nawri, Nikolai

    2015-01-01

    The offshore wind climate in Iceland is examined based on satellite synthetic aperture radar (SAR), coastal meteorological station measurements, and results from two atmospheric model data sets, HARMONIE and NORA10. The offshore winds in Iceland are highly influenced by the rugged coastline. Lee...... effects, gap flow, coastal barrier jets, and atmospheric gravity waves are not only observed in SAR, but are also modeled well from HARMONIE. Offshore meteorological observations are not available, but wind speed and wind direction measurements from coastal meteorological masts are found to compare well...

  19. Residence time and behaviour of sole and cod in the Offshore Wind farm Egmond aan Zee (OWEZ)

    NARCIS (Netherlands)

    Winter, H.V.; Aarts, G.M.; Keeken, van O.A.

    2010-01-01

    ‘Noordzeewind’ (a Nuon and Shell Wind Energy consortium) exploits a wind farm with 36 wind turbines off the coast of Egmond aan Zee: the Offshore Wind farm Egmond aan Zee (OWEZ). This project serves to evaluate the economical, technical, ecological and social effects of offshore wind farms in

  20. IEA Wind Task 23 Offshore Wind Technology and Deployment. Subtask 1 Experience with Critical Deployment Issues. Final Technical Report

    DEFF Research Database (Denmark)

    Lemming, Jørgen Kjærgaard

    The final report for IEA Wind Task 23, Offshore Wind Energy Technology and Deployment, is made up of two separate reports: Subtask 1: Experience with Critical Deployment Issues and Subtask 2: Offshore Code Comparison Collaborative (OC3). The Subtask 1 report included here provides background...... information and objectives of Task 23. It specifically discusses ecological issues and regulation, electrical system integration and offshore wind, external conditions, and key conclusions for Subtask 1. The Subtask 2 report covers OC3 background information and objectives of the task, OC3 benchmark exercises...... of aero-elastic offshore wind turbine codes, monopile foundation modeling, tripod support structure modeling, and Phase IV results regarding floating wind turbine modeling....

  1. Atmospheric stability assessment for the characterization of offshore wind conditions

    Science.gov (United States)

    Sanz Rodrigo, J.; Cantero, E.; García, B.; Borbón, F.; Irigoyen, U.; Lozano, S.; Fernande, P. M.; Chávez, R. A.

    2015-06-01

    Based on the Fino-1 offshore met mast database, different instrument set-ups and methodologies for stability characterization have been tested using non-dimensional numbers like the gradient and bulk Richardson number, and their equivalences with the Obukhov parameter ζ = z/L, which can be measured locally with the use of a sonic anemometer. These equivalences depend to a large extent on the suitability of empirical stability functions obtained in horizontally-homogeneous conditions. The bulk Richardson number method, based on Grachev and Fairall (1997) empirical function, is the least demanding measurement method for stability characterization offering a more practical approach to wind farm designers than using the sonic method. Alternatively, the AMOK method, used by FUGA wake model and also based on the bulk Richardson number, assumes surface-layer theory and avoids using stability functions, which results in a more robust formulation. A 9-class stability classification based on Sorbjan and Grachev (2010) is used to generalize the categorization of wind conditions. Based on flux-profile analysis it was concluded that unfortunately the local ζ is not sufficient to describe the scaling behaviour of the stable boundary layer. Indeed, larger wind shear than predicted by classical onshore stability functions is found, probably as a result of lower boundary layer depths.

  2. A numerical study of wind turbine-boundary layer interactions in a large offshore wind farm

    Science.gov (United States)

    Gupta, Tanvi; Baidya Roy, Somnath

    2017-04-01

    Large offshore wind farm installations are rapidly increasing all over the world driven by the availability of strong, consistent winds and the unavailability of appropriate land sites. This study quantitatively explores the interaction between wind turbines and the marine atmospheric boundary layer and its impacts on power generation in a hypothetical large offshore wind farm off the western coast of India in the Arabian Sea. The simulations are conducted using the mesoscale model WRF equipped with a wind turbine parameterization, which approximates a wind turbine as a sink of resolved kinetic energy and a source of turbulent kinetic energy. In this study, the WRF parameterization is modified to include the effects of density variations. The simulations are conducted over a 300 km x 300 km domain discretised with an 1 km grid with 10000 turbines placed in the centre. Wind turbines extract atmospheric kinetic energy and convert it into electricity. The extraction of kinetic energy from the atmospheric flow leads to two major phenomena: (1) momentum deficit in the wakes that reduce energy availability for downwind turbines and (2) enhanced vertical convergence to partly replenish the momentum deficit. Results show a 200% increase in vertical momentum convergence, with 95% of that coming from sub-grid turbulent eddies. However, the enhanced momentum convergence offsets only a small part of the momentum deficit. Consequently, there is a net reduction of almost 60% in power production for turbines in the interior of the farm compared to the turbines at the leading edge. These results suggest that a numerical model like WRF that accounts for both the momentum deficit and enhanced momentum convergence effects may provide better estimates of wind power generation than traditional wind speed density or wake model approaches.

  3. An offshore wind farm with dc grid connection and its performance under power system transients

    DEFF Research Database (Denmark)

    Deng, Fujin; Chen, Zhe

    2011-01-01

    The continuous increase in wind power penetration level brings new requirements for wind turbine integration into the network. The grid code requires that after clearance of an external short-circuit fault, grid-connected wind turbines should restore their normal operation without power loss caused...... by disconnections. This paper presents a transient performance study of an offshore wind farm with HVDC transmission for grid connection, where the wind turbines in the offshore wind farm are also connected with dc collection network. A power-reduction control strategy (PRCS) for transient performance improvement...

  4. Fixed-speed active-stall wind turbines in offshore applications

    DEFF Research Database (Denmark)

    Akhmatov, Vladislav; Nielsen, Arne Hejde

    2005-01-01

    A large offshore wind farm in the East Danish power system was commissioned in 2003 at Rodsand. The power capacity of the wind farm is 165 MW divided between 72 wind turbines. For this large offshore application, robust and well-known wind technology has been chosen in the form of fixed......-speed, active-stall wind turbines equipped with induction generators. In this paper, maintaining and improving the short-term voltage stability is discussed and systematized in terms of this wind technology. Copyright (C) 2004 John Wiley Sons, Ltd....

  5. Grid Integration of Offshore Wind Farms via VSC-HVDC – Dynamic Stability Study

    DEFF Research Database (Denmark)

    Liu, Hongzhi

    farms could seriously impact the operation and stability of their interconnected power system. To assist in maintaining the power system stability when large disturbances occur in the grid, modern offshore wind farms consisting of variable-speed wind turbines are required to provide ancillary services......-HVDC transmission are addressed. The main objectives have been to study the dynamic interactions between offshore wind farms and interconnected power systems, pinpoint the impact on the electrical grid while integrating large-scale offshore wind farms via VSC-HVDC link and propose potential solutions to improve...... the dynamic stability of the network. This research work starts with the modelling of full converter wind turbine and VSC-HVDC transmission system. Then, based on those models, the impact of integration of a large offshore wind farm into the power system through VSC-HVDC transmission is investigated...

  6. Willingness to pay for reduced visual disamenities from off-shore wind farms in Denmark

    DEFF Research Database (Denmark)

    Ladenburg, Jacob; Dubgaard, Alex

    and 50 km from the coast opposed to 8 km. The results also reveal that the WTP deviate strongly with regards to the age of the respondent and the experiences with off-shore wind farms. These properties of the WTP are believed to have significant policy related consequences. Keywords: Visual Disamenities......Expansion of the off-shore wind power capacity plays a significant role in the wind power strategy in many EU countries. However, off-shore wind farms are associated with visual disamenities. The disamenities can be reduced by locating the wind farms at larger distances from the coast. But......, the costs per kWh produced increase as the distance is augmented. In this paper, peoples’ willingness to pay for a reduction in the visual disamenity of off-shore wind farms is elicited using the economic valuation method Choice Experiments. The economic valuation scenario comprises the locations of 3600 MW...

  7. Wind Speed Estimation and Wake model Re-calibration for Downregulated Offshore Wind Farms

    Science.gov (United States)

    Göçmen Bozkurt, Tuhfe; Giebel, Gregor; Kjølstad Poulsen, Niels; Réthoré, Pierre-Elouan; Mirzaei, Mahmood

    2014-05-01

    In recent years, the wind farm sizes have increased tremendously and with increasing installed capacity, the wind farms are requested to downregulate from their maximum possible power more frequently, especially in the offshore environment. Determination of the possible (or available) power is crucial not only because the reserve power has considerable market value but also for wind farm developers to be properly compensated for the loss during downregulation. While the available power calculation is straightforward for a single turbine, it gets rather complicated for the whole wind farm due to the change in the wake characteristics. In fact, the wake losses generated by the upstream turbine(s) decrease during downregulation and the downstream turbines therefore see more wind compared to the normal operation case. Currently, the Transmission System Operators (TSOs) have no real way to determine exactly the available power of a whole wind farm which is downregulated. Therefore, the PossPOW project aims to develop a verified and internationally accepted way to determine the possible power of a down-regulated offshore wind farm. The first phase of the project is to estimate the rotor effective wind speed. Since the nacelle anemometers are not readily available and are known to have reliability issues, the proposed method is to use power, pitch angle and rotational speed as inputs and combine it with a generic Cp model to estimate the wind speed. The performance of the model has been evaluated for both normal operation and downregulation periods using two different case studies: Horns Rev-I wind farm and NREL 5MW single turbine. During downregulation, the wake losses are not as severe and the velocity deficits at the downstream turbines are smaller as if also the wake is "downregulated". On the other hand, in order to calculate the available power, the wakes that would have been produced normally (if the turbines were not curtailed) are of importance, not the

  8. Improving Maryland’s Offshore Wind Energy Resource Estimate Using Doppler Wind Lidar Technology to Assess Microtmeteorology Controls

    Directory of Open Access Journals (Sweden)

    Pé Alexandra St.

    2016-01-01

    Compared to lidar measurements, power law extrapolation estimates and operational National Weather Service models underestimated hub-height wind speeds in the WEA. In addition, lidar observations suggest the frequent development of a low-level wind maximum (LLWM, with high turbinelayer wind shear and low turbulence intensity within a turbine’s rotor layer (40m-160m. Results elucidate the advantages of using Doppler wind lidar technology to improve offshore wind resource estimates and its ability to monitor under-sampled offshore meteorological controls impact on a potential turbine’s ability to produce power.

  9. Design and Analysis of Jacket Substructures for Offshore Wind Turbines

    Directory of Open Access Journals (Sweden)

    I-Wen Chen

    2016-04-01

    Full Text Available This study focused on investigating various existing types of offshore jacket substructures along with a proposed twisted-tripod jacket type (modified jacket (MJ-structures. The architectures of the three-leg structure, as well as the patented twisted jacket structure motivated the design of the proposed MJ-structures. The dimensions of the structures were designed iteratively using static stress analysis to ensure that all structures had a similar level of load-carrying capability. The numerical global buckling analyses were performed for all structures after the validation by the scaled-down experiments. The local buckling strength of all compressive members was analyzed using the NORSOK standard. The results showed that the proposed MJ-structures possess excellent structural behavior and few structural nodes and components competitive with the patented twisted jacket structures, while still maintaining the advantages of low material usage similar to the three-leg jacket structures. This study provides alternatives for the initial selection and design of offshore wind turbine substructures for green energy applications.

  10. Harmonic Adaptability Remote Testing Method for Offshore Wind Turbines

    Directory of Open Access Journals (Sweden)

    Zimin Jiang

    2017-11-01

    Full Text Available Harmonic adaptability (HA capability is required for large-scale onshore and offshore wind turbines (WTs connected to the grid. To ensure that the distortion of the harmonic voltage at the grid access point generated by grid simulator is in accordance with the required value, this paper proposes an on-site HA remote testing method for offshore WTs to eliminate submarine cable effects. The deviation compensation method detects the integer harmonic voltage distortion based on instantaneous reactive power theory, and the deviation from the required value is compensated by series active power filter. In order to further reduce the capacity of the designed device, integer harmonics close to the resonant frequency are suppressed by the selective harmonic damping (SHD method initially. Owing to the attenuation of extreme amplification, the deviation determining the equipment capacity is decreased correspondingly. As a small synthesized impedance working for the selected frequency can suppress the amplification significantly, a low power ratings design for the SHD method can be achieved, and undesired resonance can be avoided. Simulation results indicate that the proposed method can make the harmonic distortion within the error tolerance.

  11. Legal-institutional arrangements facilitating offshore wind energy conversion systems (WECS) utilization. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Mayo, L.H.

    1977-09-01

    Concern for the continuing sufficiency of energy supplies in the U.S. has tended to direct increasing attention to unconventional sources of supply, including wind energy. Some of the more striking proposals for the utilization of wind energy relate to offshore configurations. The legal-institutional arrangements for facilitating the utilization of offshore wind energy conversion systems (WECS) are examined by positioning three program alternatives and analyzing the institutional support required for the implementation of each.

  12. Computationally Inexpensive Approach for Pitch Control of Offshore Wind Turbine on Barge Floating Platform

    OpenAIRE

    Shan Zuo; Song, Y. D.; Lei Wang; Qing-wang Song

    2013-01-01

    Offshore floating wind turbine (OFWT) has gained increasing attention during the past decade because of the offshore high-quality wind power and complex load environment. The control system is a tradeoff between power tracking and fatigue load reduction in the above-rated wind speed area. In allusion to the external disturbances and uncertain system parameters of OFWT due to the proximity to load centers and strong wave coupling, this paper proposes a computationally inexpensive robust adapti...

  13. Reliability model for offshore wind farms; Paalidelighedsmodel for havvindmoelleparker

    Energy Technology Data Exchange (ETDEWEB)

    Christensen, P.; Lundtang Paulsen, J.; Lybech Toegersen, M.; Krogh, T. [Risoe National Lab., Roskilde (Denmark); Raben, N.; Donovan, M.H.; Joergensen, L. [SEAS (Denmark); Winther-Jensen, M.

    2002-05-01

    A method for the prediction of the mean availability for an offshore windfarm has been developed. Factors comprised are the reliability of the single turbine, the strategy for preventive maintenance the climate, the number of repair teams, and the type of boats available for transport. The mean availability is defined as the sum of the fractions of time, where each turbine is available for production. The project has been carried out together with SEAS Wind Technique, and their site Roedsand has been chosen as the example of the work. A climate model has been created based on actual site measurements. The prediction of the availability is done with a Monte Carlo-simulation. Software was developed for the preparation of the climate model from weather measurements as well as for the Monte carlo-simulation. Three examples have been simulated, one with guessed parametres, and the other two with parameters more close to the Roedsand case. (au)

  14. Demand forecast of turbines in the offshore wind power industry

    DEFF Research Database (Denmark)

    Martinez-Neri, Ivan

    2014-01-01

    How important is it for a manufacturing company to be able to predict the demand of their products? How much will it lose in inventory costs due to a bad forecasting technique? And what if the product in question is composed of more than 100,000 parts and costs millions of euros a piece? This art......How important is it for a manufacturing company to be able to predict the demand of their products? How much will it lose in inventory costs due to a bad forecasting technique? And what if the product in question is composed of more than 100,000 parts and costs millions of euros a piece......? This article summarises the reasoning followed by a European manufacturer to determine the demand curve of finished offshore wind turbines and how to forecast it for the purpose of production planning....

  15. Harmonic Analysis and Active Filtering in Offshore Wind Power Plants

    DEFF Research Database (Denmark)

    Chaudhary, Sanjay Kumar; Freijedo Fernandez, Francisco Daniel; Guerrero, Josep M.

    2015-01-01

    at the point of common coupling (PCC). The resonance conditions should be avoided in all cases. This paper describes the harmonic analysis techniques applied on an OWPP network model. A method is proposed to estimate the harmonic current compensation from a shunt-connected active power filter to mitigate......Due to presence of long high voltage cable networks, and power transformers for the grid connection, the offshore wind power plants (OWPPs) are susceptible to harmonic distortion and resonances. The grid connection of OWPP should not cause the harmonic distortion beyond the permissible limits...... the harmonic voltage distortion at the PCC. Finally the harmonic distortions in the compensated and the uncompensated systems are compared to demonstrate the efficacy of the compensation....

  16. Risk-Based Operation and Maintenance of Offshore Wind Turbines

    DEFF Research Database (Denmark)

    Nielsen, Jannie Sønderkær

    For offshore wind turbines, maintenance costs are substantial due to a large number of component failures. In addition to the repair costs, equipment costs and lost production costs are large due to limited accessibility to the turbines. In order to reduce the costs, preventive methods can be used...... maintenance costs, and many studies have also been published for preventive maintenance. However, an important part is the modeling of the relationship between maintenance and reliability, which is typically not modeled in a consistent way. Therefore, the methods cannot be used directly for optimal...... maintenance planning, taking into account monitoring, inspections, preventive repairs and corrective repairs. This can be done using methods developed from a Bayesian perspective. Such methods have been developed for use in the oil and gas industry under the name Risk-Based Inspection (RBI), and are based...

  17. Integration of offshore wind farms into the local distribution network

    Energy Technology Data Exchange (ETDEWEB)

    Youssef, R.D. [and others

    2003-07-01

    This report summarises the results of a study developing static and dynamic models for a doubly-fed induction generator and the integration of the models into the commercially available and widely used power system analysis computer programme IPSA. Details are given of connection studies involving fixed speed, variable speed and double-fed induction machines; the development of optimal power flow and use of the Optimal Power Flow (OPF) tool; and voltage control studies. The system and offshore connection, connection studies and policies, technical problems, stability connection studies for wind farms with synchronous generators and transient stability connection studies for fixed speed and doubly-fed induction generators are discussed along with the integration of OPF into IPSA.

  18. Supply chain integration opportunities for the offshore wind industry

    DEFF Research Database (Denmark)

    Martinez, Ivan

    2016-01-01

    with means to overcome their current supply chain challenges. Design/methodology/approach - A comprehensive literature review was conducted involving 162 articles published in 29 peer-reviewed journals. The papers were analyzed in terms of the dimensions of SCI, research methodology, unit of analysis, level...... of analysis, type of industry and manufacturing environment being studied, integrative practices, integrative barriers and the link between SCI and performance. Findings - While SCI has been evolving to become an influential topic in the field of supply chain management, scholars have overlooked industrial......Purpose - This paper surveys the literature on supply chain integration (SCI) to identify the state of research in the various types of studied industries and manufacturing environments. The purpose of this paper is to identify academic discoveries that could provide offshore wind projects...

  19. Edge scour at scour protections around offshore wind turbine foundations

    DEFF Research Database (Denmark)

    Petersen, Thor Ugelvig; Sumer, B. Mutlu; Fredsøe, Jørgen

    2014-01-01

    experimental campaign to explain the edge sour process in steady current is presented. The three-dimensional flow field around the pile and scour protection is resolved by particle image velocimetry, showing a local increase in the hydrodynamic field leading to increased sediment transport and scour......When building offshore wind turbines with mono-pile foundations, scour protection is typically placed to avoid scouring of the soil close to the mono-pile. An important aspect is that the scour protection itself causes erosion, inflicted by the local increase in the hydrodynamic field and in turn...... increased bed shear stresses. Scour of the edge material alongside the scour protection may cause deformations and failure of the scour protection. This can reduce the stability of the stone layer and cause exposure of cables running between the mono-piles. The early stage results of an extensive...

  20. Multilink DC Transmission for Offshore Wind Power Integration

    DEFF Research Database (Denmark)

    Craciun, Bogdan-Ionut; Silva, Rodrigo Da; Teodorescu, Remus

    2012-01-01

    analysis the Multi Terminal Direct Current (MTDC) operation and focuses on the sharing of active power produced by an offshore Wind Power Plant (WPP). The first objective was to model the system in PSCAD/EMTDC simulation software and then control structure tested under different situations. The second......The High Voltage Direct Current (HVDC) system gains much more flexibility on a basis of multi terminal operation. Having extra converters brings also new ideas in sharing the active power and one of the solutions is the use of virtual impedance correlated with a droop controller. This paper...... objective was to validate the simulation on a laboratory platform using 15 kW Voltage Source Converters (VSC) and a Real Time Interface (RTI). As a result, the power sharing is validated using such methodology and the influence in the parameters can be evaluated...

  1. Harmonic Analysis of Offshore Wind Farms with Full Converter Wind Turbines

    DEFF Research Database (Denmark)

    Kocewiak, Lukasz Hubert; Hjerrild, Jesper; Bak, Claus Leth

    2009-01-01

    This paper presents the harmonic analysis of offshore wind farm (OWF) models with full converters represented as harmonic sources and measurement data on the point of common coupling (PCC) during normal operation. The model describes a wind farm (WF) with full rated converters installed connected...... to a shore with a long HV cable. The way of propagation and effects of harmonics are presented for different study cases. Modeling strategies of harmonic sources for harmonic analysis are described and compared. Different results dependent on applied harmonic models are shown and discussed in this paper...

  2. Assessment of Offshore Wind Energy Leasing Areas for the BOEM Maryland Wind Energy Area

    Energy Technology Data Exchange (ETDEWEB)

    Musial, W.; Elliott, D.; Fields, J.; Parker, Z.; Scott, G.; Draxl, C.

    2013-06-01

    The National Renewable Energy Laboratory (NREL), under an interagency agreement with the Bureau of Ocean Energy Management (BOEM), is providing technical assistance to identify and delineate leasing areas for offshore wind energy development within the Atlantic Coast Wind Energy Areas (WEAs) established by BOEM. This report focuses on NREL's evaluation of the delineation proposed by the Maryland Energy Administration (MEA) for the Maryland (MD) WEA and two alternative delineations. The objectives of the NREL evaluation were to assess MEA's proposed delineation of the MD WEA, perform independent analysis, and recommend how the MD WEA should be delineated.

  3. SAT-WIND project. Final report[Winds from satellites for offshore and coastal wind energy mapping and wind-indexing

    Energy Technology Data Exchange (ETDEWEB)

    Hasager, C.B.; Astrup, P.; Nielsen, M. (and others)

    2007-04-15

    The SAT-WIND project 'Winds from satellites for offshore and coastal wind energy mapping and wind-indexing' was a research project funded by STVF/DSF in the years 2003 to 2006 (Sagsnr. 2058-03-0006). The goal of the project was to verify the applicability of satellite wind maps derived from passive microwave, altimeter, scatterometer and imaging Synthetic Aperture Radar (SAR) technologies for wind energy tools for wind resources and wind-indexing. The study area was the Danish Seas including the North Sea, interior seas and the Baltic Sea. The report describes technical details on the satellite data sources including: 1) passive microwave (SSM/I, AMSR-E), 2) passive microwave polarimetric (WindSat), 3) scatterometer (ERS, QuikSCAT, Midori-2 and NSCAT), 4) altimeter (ERS, Topex, Poseidon, GFO-1, Jason-1), 5) SAR (ERS, Envisat). The SAR wind maps were treated in S-WAsP developed by Risoe National Laboratory in cooperation with GRAS A/S in the innovative project SAT-WIND-SMV (Sagsnr. 2104-05-0084) in the years 2005 and 2006 in parallel with SAT-WIND. The results from the SAT-WIND project are presented. These include ocean wind statistics, offshore wind resource estimates and comparison results for wind-indexing. (au)

  4. Estimating the Economic Potential of Offshore Wind in the United States

    Energy Technology Data Exchange (ETDEWEB)

    Beiter, P.; Musial, W.; Smith, A.; Lantz, E.; Kilcher, L.; Damiani, R.; Maness, M.; Sirnivas, S.; Stehly, T.; Gevorgian, V.; Mooney, M.; Scott, G.

    2016-05-23

    The potential for cost reduction and market deployment for offshore wind varies considerably within the United States. This analysis estimates the future economic viability of offshore wind at more than 7,000 sites under a variety of electric sector and cost reduction scenarios. Identifying the economic potential of offshore wind at a high geospatial resolution can capture the significant variation in local offshore resource quality, costs, and revenue potential. In estimating economic potential, this article applies a method initially developed in Brown et al. (2015) to offshore wind and estimates the sensitivity of results under a variety of most likely electric sector scenarios. For the purposes of this analysis, a theoretical framework is developed introducing a novel offshore resource classification system that is analogous to established resource classifications from the oil and gas sector. Analyzing economic potential within this framework can help establish a refined understanding across industries of the technology and site-specific risks and opportunities associated with future offshore wind development. The results of this analysis are intended to inform the development of the U.S. Department of Energy's offshore wind strategy.

  5. Great expectations for offshore wind turbines : Emulation of wind farm design to anticipate their value for customers

    NARCIS (Netherlands)

    Zaaijer, M.B.

    2013-01-01

    To date, the technical feasibility of making electricity from offshore wind energy has been convincingly proven. However, the current challenge is to reduce the costs of this form of energy. One of the aspects playing a role in cost reduction is the optimisation of the wind turbine. The wind turbine

  6. Effects of an Offshore Wind Farm (OWF) on the Common Shore Crab Carcinus maenas: Tagging Pilot Experiments in the Lillgrund Offshore Wind Farm (Sweden).

    Science.gov (United States)

    Langhamer, Olivia; Holand, Håkon; Rosenqvist, Gunilla

    2016-01-01

    Worldwide growth of offshore renewable energy production will provide marine organisms with new hard substrate for colonization in terms of artificial reefs. The artificial reef effect is important when planning offshore installations since it can create habitat enhancement. Wind power is the most advanced technology within offshore renewable energy sources and there is an urgent need to study its impacts on the marine environment. To test the hypothesis that offshore wind power increases the abundance of reef species relative to a reference area, we conduct an experiment on the model species common shore crab (Carcinus maenas).Overall, 3962 crabs were captured, observed, marked and released in 2011 and 1995 crabs in 2012. Additionally, carapace size, sex distribution, color morphs and body condition was recorded from captured crabs. We observed very low recapture rates at all sites during both years which made evaluating differences in population sizes very difficult. However, we were able to estimate population densities from the capture record for all three sites. There was no obvious artificial reef effect in the Lillgrund wind farm, but a spill-over effect to nearby habitats cannot be excluded. We could not find any effect of the wind farm on either, morphs, sex distribution or condition of the common shore crab. Our study found no evidence that Lillgrund wind farm has a negative effect on populations of the common shore crab. This study provides the first quantitative and experimental data on the common shore crab in relation to offshore wind farms.

  7. Effects of an Offshore Wind Farm (OWF on the Common Shore Crab Carcinus maenas: Tagging Pilot Experiments in the Lillgrund Offshore Wind Farm (Sweden.

    Directory of Open Access Journals (Sweden)

    Olivia Langhamer

    Full Text Available Worldwide growth of offshore renewable energy production will provide marine organisms with new hard substrate for colonization in terms of artificial reefs. The artificial reef effect is important when planning offshore installations since it can create habitat enhancement. Wind power is the most advanced technology within offshore renewable energy sources and there is an urgent need to study its impacts on the marine environment. To test the hypothesis that offshore wind power increases the abundance of reef species relative to a reference area, we conduct an experiment on the model species common shore crab (Carcinus maenas.Overall, 3962 crabs were captured, observed, marked and released in 2011 and 1995 crabs in 2012. Additionally, carapace size, sex distribution, color morphs and body condition was recorded from captured crabs. We observed very low recapture rates at all sites during both years which made evaluating differences in population sizes very difficult. However, we were able to estimate population densities from the capture record for all three sites. There was no obvious artificial reef effect in the Lillgrund wind farm, but a spill-over effect to nearby habitats cannot be excluded. We could not find any effect of the wind farm on either, morphs, sex distribution or condition of the common shore crab. Our study found no evidence that Lillgrund wind farm has a negative effect on populations of the common shore crab. This study provides the first quantitative and experimental data on the common shore crab in relation to offshore wind farms.

  8. Effects of an Offshore Wind Farm (OWF) on the Common Shore Crab Carcinus maenas: Tagging Pilot Experiments in the Lillgrund Offshore Wind Farm (Sweden)

    Science.gov (United States)

    Langhamer, Olivia; Holand, Håkon; Rosenqvist, Gunilla

    2016-01-01

    Worldwide growth of offshore renewable energy production will provide marine organisms with new hard substrate for colonization in terms of artificial reefs. The artificial reef effect is important when planning offshore installations since it can create habitat enhancement. Wind power is the most advanced technology within offshore renewable energy sources and there is an urgent need to study its impacts on the marine environment. To test the hypothesis that offshore wind power increases the abundance of reef species relative to a reference area, we conduct an experiment on the model species common shore crab (Carcinus maenas).Overall, 3962 crabs were captured, observed, marked and released in 2011 and 1995 crabs in 2012. Additionally, carapace size, sex distribution, color morphs and body condition was recorded from captured crabs. We observed very low recapture rates at all sites during both years which made evaluating differences in population sizes very difficult. However, we were able to estimate population densities from the capture record for all three sites. There was no obvious artificial reef effect in the Lillgrund wind farm, but a spill-over effect to nearby habitats cannot be excluded. We could not find any effect of the wind farm on either, morphs, sex distribution or condition of the common shore crab. Our study found no evidence that Lillgrund wind farm has a negative effect on populations of the common shore crab. This study provides the first quantitative and experimental data on the common shore crab in relation to offshore wind farms. PMID:27780212

  9. Offshore Wind Jobs and Economic Development Impacts in the United States: Four Regional Scenarios

    Energy Technology Data Exchange (ETDEWEB)

    Tegen, S. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Keyser, D. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Flores-Espino, F. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Miles, J. [James Madison Univ., Harrisonburg, VA (United States); Zammit, D. [James Madison Univ., Harrisonburg, VA (United States); Loomis, D. [Great Lakes Wind Network, Cleveland, OH (United States)

    2015-02-01

    This report uses the offshore wind Jobs and Economic Development Impacts (JEDI) model and provides four case studies of potential offshore deployment scenarios in different regions of the United States: the Southeast, the Great Lakes, the Gulf Coast, and the Mid-Atlantic. Researchers worked with developers and industry representatives in each region to create potential offshore wind deployment and supply chain growth scenarios, specific to their locations. These scenarios were used as inputs into the offshore JEDI model to estimate jobs and other gross economic impacts in each region.

  10. Offshore wind farms in the local community - a survey at Nysted offshore wind farm. Background report; Havvindmoeller i lokalomraedet - en undersoegelse ved Nysted havmoellepark. Baggrundsrapport

    Energy Technology Data Exchange (ETDEWEB)

    Kuehn, S.

    2005-07-15

    This report is part of a socio-economic project about offshore wind farms' influence on the local community. The project is part of the monitoring programme in connection with the establishment of the offshore wind farms at Horns Rev and Nysted. The socio-economic project consists of a sociological and an environment-economic project. This report is part of the sociological project which has the purpose of identifying attitudes towards the wind farm before and after the erection with a view to identify possible changes in opinions and reasons for these changes. (BA)

  11. Development of Seismic Demand for Chang-Bin Offshore Wind Farm in Taiwan Strait

    Directory of Open Access Journals (Sweden)

    Yu-Kai Wang

    2016-12-01

    Full Text Available Taiwan is located on the Pacific seismic belt, and the soil conditions of Taiwan’s offshore wind farms are softer than those in Europe. To ensure safety and stability of the offshore wind turbine supporting structures, it is important to assess the offshore wind farms seismic forces reasonably. In this paper, the relevant seismic and geological data are obtained for Chang-Bin offshore wind farm in Taiwan Strait, the probabilistic seismic hazard analysis (PSHA is carried out, and the first uniform hazard response spectrum for Chang-Bin offshore wind farm is achieved. Compared with existing design response spectrum in the local regulation, this site-specific seismic hazard analysis has influence on the seismic force considered in the design of supporting structures and therefore affects the cost of the supporting structures. The results show that a site-specific seismic hazard analysis is required for high seismic area. The paper highlights the importance of seismic hazard analysis to assess the offshore wind farms seismic forces. The follow-up recommendations and research directions are given for Taiwan’s offshore wind turbine supporting structures under seismic force considerations.

  12. International activities and experience in offshore wind power generation; Internationale Aktivitaeten und Erfahrungen im Bereich der Offshore-Windenergienutzung

    Energy Technology Data Exchange (ETDEWEB)

    Rehfeldt, K.; Gerdes, G.J.

    2002-01-01

    Current activities in the area of offshore wind energy are being made only in the European Community in the form of concrete plans or as projects. Denmark and Sweden began as pioneers in the setting up of offshore wind parks along their coast in the Baltic Sea. As a world-wide first, Denmark saw the practicality of offshore wind energy as a way of reducing the emission of CO{sub 2} and opening new doors in the wind energy branch. Essential is not to name the ambitious goals, but that at the designated suitable regions, pilot projects are implemented therefore initiating extensive research and development projects. Our European neighbours have shown us through their own experience what great potential and underlying dynamic offshore wind energy has. The development of projects can be given with confidence to private sector, if however the main consensus from promoters and environmentalists is desired, then in this instance the governmental participation as a guide would be desirable. (orig.)

  13. Offshore Wind Resources Assessment from Multiple Satellite Data and WRF Modeling over South China Sea

    Directory of Open Access Journals (Sweden)

    Rui Chang

    2015-01-01

    Full Text Available Using accurate inputs of wind speed is crucial in wind resource assessment, as predicted power is proportional to the wind speed cubed. This study outlines a methodology for combining multiple ocean satellite winds and winds from WRF simulations in order to acquire the accurate reconstructed offshore winds which can be used for offshore wind resource assessment. First, wind speeds retrieved from Synthetic Aperture Radar (SAR and Scatterometer ASCAT images were validated against in situ measurements from seven coastal meteorological stations in South China Sea (SCS. The wind roses from the Navy Operational Global Atmospheric Prediction System (NOGAPS and ASCAT agree well with these observations from the corresponding in situ measurements. The statistical results comparing in situ wind speed and SAR-based (ASCAT-based wind speed for the whole co-located samples show a standard deviation (SD of 2.09 m/s (1.83 m/s and correlation coefficient of R 0.75 (0.80. When the offshore winds (i.e., winds directed from land to sea are excluded, the comparison results for wind speeds show an improvement of SD and R, indicating that the satellite data are more credible over the open ocean. Meanwhile, the validation of satellite winds against the same co-located mast observations shows a satisfactory level of accuracy which was similar for SAR and ASCAT winds. These satellite winds are then assimilated into the Weather Research and Forecasting (WRF Model by WRF Data Assimilation (WRFDA system. Finally, the wind resource statistics at 100 m height based on the reconstructed winds have been achieved over the study area, which fully combines the offshore wind information from multiple satellite data and numerical model. The findings presented here may be useful in future wind resource assessment based on satellite data.

  14. Energy Yield prediction of offshore wind farm clusters at the EERA–DTOC European project

    DEFF Research Database (Denmark)

    Cantero, E.; Sanz, J.; Lozano, S.

    . A demonstration phase at the end of the project will assess the value of the integrated design tool with the help of potential end-users from industry. In order to provide an accurate value of the expected net energy yield, the offshore wind resource assessment process has been reviewed as well as the sources......A new integrated design tool for optimization of offshore wind farm clusters is under development in the European Energy Research Alliance – Design Tools for Offshore wind farm Cluster project (EERA DTOC). The project builds on already established design tools from the project partners and possibly...... third-party models. Wake models have been benchmarked on the Horns Rev-1 and, currently, on the Lillgrund wind farm test cases. Dedicated experiments from 'BARD Offshore 1' wind farm will using scanning lidars will produce new data for the validation of wake models. Furthermore, the project includes...

  15. Is the distribution and abundance of waterbirds altered in and around Danish Offshore wind farms?

    DEFF Research Database (Denmark)

    Petersen, Ib Krag

    In 1999 a Danish demonstration programme concerning offshore wind farms was initiated. The aim was to evaluate environmental and technical aspects in relation to introducing these new structures at sea. Aarhus University was involved in ornithological investigations in that respect. Monitoring...... programmes for Horns Rev 1 and the Nysted offshore wind farms were initiated, and after the erection of the turbines post-construction monitoring programmes were initiated. Data from these investigations will be touched upon. At Nysted offshore wind farm common eiders (Somateria mollissima) avoided flying...... through the wind farm to a large extent and long-tailed ducks (Clangula hyemalis) utilised the area of the wind farm significantly less after the appearance of the wind farm than before. At Horns Rev 1 it seemed that red-throated diver (Gavia stellata) avoided utilising the area of the wind farm...

  16. Potential for Jobs and Economic Development from Offshore Wind in California

    Energy Technology Data Exchange (ETDEWEB)

    Tegen, Suzanne

    2016-11-02

    In California's future scenarios, energy demand increases with population growth and productivity. Decision-makers will have to make choices about which energy resources to utilize, and offshore wind offers one option for carbon-free electricity with the potential for increased local jobs. This presentation discusses results from an NREL report, Floating Offshore Wind in California: Gross Potential for Jobs and Economic Impacts from Two Future Scenarios. Presenter Suzanne Tegen describes the Jobs and Economic Development Impact (JEDI) model and its results for two offshore wind scenarios in California. She discusses different assumptions and how they affect the scenarios.

  17. Response Analysis of a Spar-Type Floating Offshore Wind Turbine Under Atmospheric Icing Conditions

    DEFF Research Database (Denmark)

    Etemaddar, Mahmoud; Hansen, Martin Otto Laver; Moan, Torgeir

    2014-01-01

    One of the challenges for the development of wind energy in offshore cold-climate regions is atmospheric icing. This paper examines the effects of atmospheric icing on power production, overall performance, and extreme loads of a 5-MW spar-type floating offshore wind turbine during power production......, normal and emergency rotor shutdown, extreme gusts, and survival conditions. Atmospheric icing is simulated by using the ice accretion simulation code LEWICE. A CFD method is used to estimate the blade aerodynamic degradation due to icing. The effects of icing on one, two, or three blades are compared......, as are the effects of atmospheric icing on land-based and offshore wind turbines....

  18. Potential Economic Impacts from Offshore Wind in the Mid-Atlantic Region (Fact Sheet)

    Energy Technology Data Exchange (ETDEWEB)

    Keyser, D. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Tegen, S. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Flores, F. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Zammit, D. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Kraemer, M. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Miles, J. [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2014-01-01

    Offshore wind is a clean, renewable source of energy and can be an economic driver in the United States. To better understand the employment opportunities and other potential regional economic impacts from offshore wind development, the U.S. Department of Energy (DOE) funded research that focuses on four regions of the country. The studies use multiple scenarios with various local job and domestic manufacturing content assumptions. Each regional study uses the new offshore wind Jobs and Economic Development Impacts (JEDI) model, developed by the National Renewable Energy Laboratory. This fact sheet summarizes the potential economic impacts for the Mid-Atlantic region.

  19. Potential Economic Impacts from Offshore Wind in the Gulf of Mexico Region (Fact Sheet)

    Energy Technology Data Exchange (ETDEWEB)

    Flores, F. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Keyser, D. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Tegen, S. [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2014-01-01

    Offshore wind is a clean, renewable source of energy and can be an economic driver in the United States. To better understand the employment opportunities and other potential regional economic impacts from offshore wind development, the U.S. Department of Energy (DOE) funded research that focuses on four regions of the country. The studies use multiple scenarios with various local job and domestic manufacturing content assumptions. Each regional study uses the new offshore wind Jobs and Economic Development Impacts (JEDI) model, developed by the National Renewable Energy Laboratory. This fact sheet summarizes the potential economic impacts for the Gulf of Mexico region.

  20. Potential Economic Impacts from Offshore Wind in the Great Lakes Region (Fact Sheet)

    Energy Technology Data Exchange (ETDEWEB)

    Tegen, S. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Keyser, D. [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2014-01-01

    Offshore wind is a clean, renewable source of energy and can be an economic driver in the United States. To better understand the employment opportunities and other potential regional economic impacts from offshore wind development, the U.S. Department of Energy (DOE) funded research that focuses on four regions of the country. The studies use multiple scenarios with various local job and domestic manufacturing content assumptions. Each regional study uses the new offshore wind Jobs and Economic Development Impacts (JEDI) model, developed by DOE's National Renewable Energy Laboratory. This fact sheet summarizes the potential economic impacts identified by the study for the Great Lakes region.

  1. Study on offshore wind farm integration mode and reactive power compensation

    Energy Technology Data Exchange (ETDEWEB)

    Bian, Xiaoyan; Hong, Lijun; Fu, Yang [Shanghai Univ. of Electrical Power (China). Power and Automation Engineering Dept.

    2013-07-01

    Two typical offshore wind farm grid-connected modes are introduced and dynamic characteristics under their modes are compared from the simulation by PSS/E. The result shows that offshore wind farm with VSC-HVDC has better dynamic characteristics on fault isolation, reactive power compensation, and fault ride through ability. In addition, STATCOM has been applied to the offshore wind farm, the simulation results indicates that it can improve the bus voltage stability in fault and maintain the voltage level under a small perturbation.

  2. Converting Offshore Wind into Electricity. The Netherlands' contribution to offshore wind energy knowledge. We at Sea research programme 2004-2010

    Energy Technology Data Exchange (ETDEWEB)

    Beurskens, J. (ed.); Westra, C.; Rademakers, L. [ECN Wind Energy, Petten (Netherlands); De Vries, E. [Rotation Consultancy, Amersfoort (Netherlands); Zaaijer, M. [Delft University of Technology TUD, Delft (Netherlands); Asjes, J.; Lindeboom, H. [IMARES, Wageningen UR, Wageningen (Netherlands); Van Hulle, F. [XP Wind, Brussels (Belgium)

    2011-07-01

    This book offers an overview of the results of the Netherlands' offshore wind energy research program We at Sea. The program was carried out from 2004 to 2010 and covered the entire spectrum of topics associated with the accelerated implementation of large scale offshore wind power on the North Sea. The topics, described in this book include: Wind turbines and wind farms (new concepts and design tools); Transport, installation and logistics; Operation and maintenance; Grid integration; Ecological impacts and spatial planning; Implementation scenarios; Industrial and societal aspects. The We at Sea programme's results are presented in the context of worldwide advances in large scale implementation of offshore wind power and science and technology development. From the We at Sea topics, selected projects are summarised. These give a comprehensive view of the contribution of the Netherlands' technical and scientific community to the knowledge base of offshore wind power. In particular significant results were achieved in the development of operation and maintenance (cost estimation and operational optimisation), access technology, new concepts and the analysis of the impact of wind turbines on marine life and birds.

  3. Offshore wind energy. Innovators talking; Wind op zee. Innovators aan het woord

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2013-02-15

    Qualitative studies have been conducted of the results of completed projects focused on energy innovation, spread over the seven themes of the top sector Energy: Energy saving in industry, Energy conservation in the built environment, Gas, Bio-energy, Smart grids, Offshore Wind, Solar PV. This provides insight into the follow-up activities and lessons of some EOS (Energy Research Subsidy) completed projects with the aim to inspire, connect and strengthen the TKIs (Topconsortia for Knowledge and Innovation) and individual companies and researchers working on energy innovation. This report concerns the research on offshore wind energy [Dutch] Er is een kwalitatief onderzoek uitgevoerd naar de resultaten van afgeronde projecten gericht op energie-innovatie, verdeeld over de zeven thema's van de topsector Energie: Energiebesparing in de industrie; Energiebesparing in de gebouwde omgeving; Gas; Bio-energie; Smart grids; Wind op zee; Zon-pv. Daarmee wordt inzicht gegeven in de vervolgactiviteiten en lessen van een aantal afgesloten EOS-projecten (Energie Onderzoek Subsidie) met het oog op het inspireren, verbinden en versterken van de TKI's (Topconsortia voor Kennis en Innovatie) en individuele bedrijven en onderzoekers die werken aan energie-innovatie. Dit rapport betreft het onderzoek naar wind op zee.

  4. Comparison of API & IEC Standards for Offshore Wind Turbine Applications in the U.S. Atlantic Ocean: Phase II; March 9, 2009 - September 9, 2009

    Energy Technology Data Exchange (ETDEWEB)

    Jha, A.; Dolan, D.; Gur, T.; Soyoz, S.; Alpdogan, C.

    2013-01-01

    This report compares two design guidelines for offshore wind turbines: Recommended Practice for Planning, Designing, and Constructing Fixed Offshore Platform Structures and the International Electrotechnical Commission 61400-3 Design Requirements for Offshore Wind Turbines.

  5. AC-DC integrated load flow calculation for variable speed offshore wind farms

    DEFF Research Database (Denmark)

    Zhao, Menghua; Chen, Zhe; Blaabjerg, Frede

    2005-01-01

    This paper proposes a sequential AC-DC integrated load flow algorithm for variable speed offshore wind farms. In this algorithm, the variable frequency and the control strategy of variable speed wind turbine systems are considered. In addition, the losses of wind turbine systems and the losses...... of converters are also integrated into the load flow algorithm. As a general algorithm, it can be applied to different types of wind farm configurations, and the load flow is related to the wind speed....

  6. The offshore wind resources assessment application of floating LiDAR in the Taiwan Strait

    Science.gov (United States)

    Hsuan, Chung-Yao; Wu, Yu-Ting; Lin, Ta-Hui

    2015-04-01

    Wind and wave measurements of a Floating LiDAR (Light Detection And Ranging) Device (FLD) are performed on the site of Fuhai Offshore Wind Farm in the Taiwan Strait. The location of the deployment is situated 10 kilometers off-coast of Changhua County, and the anchored water depth is 25 meters. It is the very first time in Asia Pacific Region to use such device for tasks of offshore wind and wave measurement. Six range gate heights were set at 55m, 71m, 90m, 110m, 150m and 200m from the FLD sensor lens. Wind speeds and wind directions were measured by a remote sensing technology. Wave heights and periods were also measured by the buoy wave sensor. A validation campaign of NCKU WindSentinel has performed by a portable LiDAR (WINDCUBE v2) at Hsing-Da Harbor in the south of Taiwan from October 16th to 26th, 2013. The results showed good agreements with 10 minute averaged data of the wind speed and wind direction measured by the two LiDARs. NCKU WindSentinel data are planning comparisons with Fuhai's offshore fixed mast data when the meteorological mast is completed. The goal is to convince the wind energy community that FLD are a reliable and cost effective way of obtaining data for resource assessment. Until this moment, The FLD are observing and measuring the offshore wind farm's meteorological and oceanographic data. In September of 2014, a mild typhoon (Fung-Wong) passed through from east of Taiwan. NCKU WindSentinel continuously measured during typhoon period in the sea. The present preliminary measurements campaign presented the convenient and more cost effective option of the FLD, which may be a key tool for assessment of offshore wind resources in the near-future offshore wind farm developments.

  7. Market analysis offshore wind energy; Marktanalyse Windenergie auf See

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2015-07-01

    The North Sea has compared to the Baltic Sea due the available space offering a significantly larger Potential. Compared to the North Sea are the exploitable Potential of the Baltic Sea coast, however, significantly more closer to the coast, which not only for the network connection but also for the construction and operation of plants efficiency benefits may have. It is still unclear whether the available areas of the territorial sea Baltic Sea in relevant scale can be extended. The corresponding Spatial planning process was in 2014 by Mecklenburg- Vorpommern initiated. The analysis of the Federal Offshore Plan fixed Clusters of the offshore grid development plan in structured areas for the North and Baltic Seas (1-5), shows that at least in the expansion phase by 2025, possibly also 2030 the coastally zones 1 and 2 in North and Baltic provide a sufficient surface potential and at the same time with respect to an efficient and structured Network expansion should be developed. The expansion path up to 2020 allows the industry to realize the proposed decreasing trend of cost of over 30 percent. The recognizable today Cost reductions have so far have to take into account in the context of the development the tender design. This also applies to the question of optimal Park and plant designs for the energy industry View. In addition to each project internal difficulties at the network as at wind farm site there are significant interface problems between the wind farm and grid connection. This is, inter alia, due to the different implementation periods after commissioning. An acceleration or flexibilization of the grid connections (in particular DC) would substantially benefit to bring and could lead to a significant improvement of the competitive situation. The competition from sides of the wind turbine manufacturer is currently formed little heterogeneous. On the part of investors, there is in the meantime a relatively high number of potential future Investors which

  8. Sociological investigation of the reception of Nysted Offshore wind farm. Annual report 2004[Denmark

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2005-08-15

    This annual report presents the work related to the sociological part of a socio-economic project that examines the effects on the local communities of the two demonstration off-shore wind farms: Horns Rev Offshore Wind Farm, west of Blaavands Huk in Jutland, and Nysted Offshore Wind Farm, south of Lolland. The socio-economic project is part of the monitoring programme in connection with the construction of the offshore wind farms. Unlike projects, which examine the impact of the wind farms on nature, the socio-economic project did not start until 2003. The other part of the socio-economic project is an environmental-economic study that among other things examines the preferences of the population in relation to location of the wind farm and the willingness to pay for increasing the distance between the wind farms and the coast. This sociological study is qualitative. The study is divided into three phases, as the aim is to investigate the public community's attitude towards the erection of an offshore wind farm before and after the construction of the wind farm. This aim is based on the assumption that attitudes may change once the wind farm is erected and the population has experienced the visibility of the wind farm, etc. The division into phases is as follows: 1) Phase 1 treats the conditions as they were before the erection of Nysted Offshore Wind Farm. 2) Phase 2 is a study of the development in attitudes towards Horns Rev Offshore Wind Farm a year after erection. 3) Phase 3 comprises a follow-up study of the local area at Nysted Offshore Wind Farm. The Horns Rev study was conclusive and was carried out September-November 2003. The study at Nysted on the other hand implies two parts. The first was carried out April-August 2003 and identified attitudes before the wind farm was completed. A follow-up study in August-December 2004 served the purpose of revealing the extent of attitude changes regarding the wind farm and the development of these changes of

  9. Offshore wind climatology based on synergetic use of Envisat ASAR, ASCAT and QuikSCAT

    DEFF Research Database (Denmark)

    Hasager, Charlotte Bay; Mouche, Alexis; Badger, Merete

    2015-01-01

    The offshore wind climatology in the Northern European seas is analysed from ten years of Envisat synthetic aperture radar (SAR) images using a total of 9256 scenes, ten years of QuikSCAT and two years of ASCAT gridded ocean surface vector wind products and high-quality wind observations from four...

  10. 75 FR 82055 - Commercial Leasing for Wind Power on the Outer Continental Shelf (OCS) Offshore Massachusetts...

    Science.gov (United States)

    2010-12-29

    ... and Enforcement [Docket No. BOEM-2010-0063] Commercial Leasing for Wind Power on the Outer Continental..., Regulation and Enforcement, Interior. ACTION: RFI in Commercial Wind Energy Leasing Offshore Massachusetts... more commercial leases for the construction of a wind energy project(s) on the Outer Continental Shelf...

  11. 77 FR 5545 - Commercial Leasing for Wind Power Development on the Outer Continental Shelf (OCS) Offshore...

    Science.gov (United States)

    2012-02-03

    ... Bureau of Ocean Energy Management Commercial Leasing for Wind Power Development on the Outer Continental... lessee to propose the construction of a wind energy project(s) on the OCS offshore Virginia. Although the... specific interest in the acquisition of commercial wind lease(s) in some or all of the area and to...

  12. Extreme Motion Predictions for Deepwater TLP Floaters for Offshore Wind Turbines

    DEFF Research Database (Denmark)

    Jensen, Jørgen Juncher; Mansour, A. E.

    2006-01-01

    The paper addresses the calculation of extreme motion of a TLP type of floater for an offshore wind turbine. Motions are of significant importance for the operation of the wind turbine as they influence the blade loadings and hence the downtime of the wind turbine energy production. The paper ill...

  13. Spatial planning of offshore wind farms: A windfall to marine environmental protection?

    NARCIS (Netherlands)

    Punt, M.J.; Groeneveld, R.A.; Ierland, van E.C.; Stel, J.

    2009-01-01

    Wind farms are often planned offshore where wind conditions are favourable and the visual impact is less important. Wind farms have both positive and negative effects on the marine environment. Negative effects include bird collisions, underwater sounds and electromagnetic fields, whilst positive

  14. Effects on harbour porpoises from Roedsand 2 Off-shore Wind Farm

    Energy Technology Data Exchange (ETDEWEB)

    Teilmann, J.; Tougaard, J.; Carstensen, J.

    2012-11-15

    E.ON Vind Sverige has been commissioned the construction of Roedsand 2 Offshore Wind Farm comprising 90 wind turbines, south of Lolland-Falster, Denmark. The location of the wind farm is 3 km west of the existing Nysted Offshore Wind Farm with 72 turbines. In combination the two wind farms represents the largest wind farm area in the world. Porpoises were monitored by automatic acoustic dataloggers (T-PODs) according to a statistical BACI design and deployed during baseline (Sep 2008-Feb 2009) and during operation (Sep 2011-Mar 2012). These instruments were deployed at 10 stations covering a coastal stretch of 35 km from Gedser to Roedby, including the wind farm area with reference areas on both sides. In addition, background noise at four of the T-POD stations was recorded by automatic noise loggers. In order to assess the potential cumulative effect of two adjacent wind farms, similar data from the Nysted Offshore Wind Farm were also analysed. We found no overall change in echolocation activity over the entire monitoring area from baseline to operation of Roedsand 2 Offshore Wind Farm. Also, there was no significant change in the echolocation activity in Roedsand 2 Offshore Wind Farm relative to each or a combination of the three reference areas, i.e. changes from baseline to operation were similar in the impact and reference areas. Also no significant change in noise levels audible to porpoises was found. This could be due to a generally high noise level in the area, masking the turbine noise or that the noise loggers in the wind farm were deployed between the wind turbines, i.e. at distances {approx}350-450 m from the turbines. This study also shows that the echolocation activity is still significantly lower in Nysted Offshore Wind Farm since the baseline in 2001-2002, although the difference seem to gradually diminish possibly due to a habituation of the porpoises to the wind farm or better feeding posibilities. We found no cumulative effect of the two wind

  15. Environmental Monitoring - Lillgrund Offshore Wind Farm. Lillgrund Pilot Project

    Energy Technology Data Exchange (ETDEWEB)

    Davy, Thomas (Vattenfall Vindkraft AB, Stockholm (Sweden))

    2009-02-15

    The purpose of this report is to describe the environmental monitoring measures performed for the Lillgrund Offshore Wind Farm and to summarize the results and conclusions. Construction work started in 2006 and the plant was energized in December 2007. At the time of construction Lillgrund was the third largest wind farm offshore in the world and the first large offshore wind farm in Sweden. The purpose of the environmental monitoring is to ensure that there are no negative impacts on the environment stemming from construction of the Lillgrund wind farm as well as to ensure that the conditions stated by the authorities and the Company's commitments are met. The aim is also to collect more information and knowledge on the possible environmental impact for future offshore wind farm projects. For the Lillgrund project, all monitoring programs were included in one document, Monitoring Program - Lillgrund. It was included as part of the procedures to ensure that the Swedish legal requirements on operators control were followed. The authorities approved the document before construction started. The monitoring measures performed during the construction phase included: - A feedback and monitoring program on dredging and spillage; - A feedback and monitoring program on flora and fauna; - Studies and inspections of the refilling and re-establishment of the sea bottom; - Procedure for operators control. The mean measured sediment spillage, as part of the monitoring program on dredging and spillage, varied between 4.6 - 4.8% depending on dredger used. The maximum value allowed by the conditions is 5%. In general, the calculated values for suspended material were limited and the critical value of 0.01 kg/m3 was exceeded only in minor areas for a very limited time. No corrective actions were required. The deposition of sediment was very low and even at the most effected sites it was only just over 1 mm. The largest dredging volumes were for the foundation work, in total 82

  16. Assessment of offshore wind power potential in the Aegean and Ionian Seas based on high-resolution hindcast model results

    Directory of Open Access Journals (Sweden)

    Takvor Soukissian

    2017-03-01

    Full Text Available In this study long-term wind data obtained from high-resolution hindcast simulations is used to analytically assess offshore wind power potential in the Aegean and Ionian Seas and provide wind climate and wind power potential characteristics at selected locations, where offshore wind farms are at the concept/planning phase. After ensuring the good model performance through detailed validation against buoy measurements, offshore wind speed and wind direction at 10 m above sea level are statistically analyzed on the annual and seasonal time scale. The spatial distribution of the mean wind speed and wind direction are provided in the appropriate time scales, along with the mean annual and the inter-annual variability; these statistical quantities are useful in the offshore wind energy sector as regards the preliminary identification of favorable sites for exploitation of offshore wind energy. Moreover, the offshore wind power potential and its variability are also estimated at 80 m height above sea level. The obtained results reveal that there are specific areas in the central and the eastern Aegean Sea that combine intense annual winds with low variability; the annual offshore wind power potential in these areas reach values close to 900 W/m2, suggesting that a detailed assessment of offshore wind energy would be worth noticing and could lead in attractive investments. Furthermore, as a rough estimate of the availability factor, the equiprobable contours of the event [4 m/s ≤ wind speed ≤ 25 m/s] are also estimated and presented. The selected lower and upper bounds of wind speed correspond to typical cut-in and cut-out wind speed thresholds, respectively, for commercial offshore wind turbines. Finally, for seven offshore wind farms that are at the concept/planning phase the main wind climate and wind power density characteristics are also provided.

  17. An Integrated Approach To Offshore Wind Energy Assessment: Great Lakes 3D Wind Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Barthelmie, R. J. [Cornell Univ., Ithaca, NY (United States). Sibley School of Mechanical & Aerospace Engineering; Pryor, S. C. [Cornell Univ., Ithaca, NY (United States). Dept. of Earth and Atmospheric Sciences

    2017-09-18

    This grant supported fundamental research into the characterization of flow parameters of relevance to the wind energy industry focused on offshore and the coastal zone. A major focus of the project was application of the latest generation of remote sensing instrumentation and also integration of measurements and numerical modeling to optimize characterization of time-evolving atmospheric flow parameters in 3-D. Our research developed a new data-constrained Wind Atlas for the Great Lakes, and developed new insights into flow parameters in heterogeneous environments. Four experiments were conducted during the project: At a large operating onshore wind farm in May 2012; At the National Renewable Energy Laboratory National Wind Technology Center (NREL NWTC) during February 2013; At the shoreline of Lake Erie in May 2013; and At the Wind Energy Institute of Canada on Prince Edward Island in May 2015. The experiment we conducted in the coastal zone of Lake Erie indicated very complex flow fields and the frequent presence of upward momentum fluxes and resulting distortion of the wind speed profile at turbine relevant heights due to swells in the Great Lakes. Additionally, our data (and modeling) indicate the frequent presence of low level jets at 600 m height over the Lake and occasions when the wind speed profile across the rotor plane may be impacted by this phenomenon. Experimental data and modeling of the fourth experiment on Prince Edward Island showed that at 10-14 m escarpment adjacent to long-overseas fetch the zone of wind speed decrease before the terrain feature and the increase at (and slightly downwind of) the escarpment is ~3–5% at turbine hub-heights. Additionally, our measurements were used to improve methods to compute the uncertainty in lidar-derived flow properties and to optimize lidar-scanning strategies. For example, on the basis of the experimental data we collected plus those from one of our research partners we advanced a new methodology to

  18. Effect of Second-Order Hydrodynamics on Floating Offshore Wind Turbines: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Roald, L.; Jonkman, J.; Robertson, A,; Chokani, N.

    2013-07-01

    Offshore winds are generally stronger and more consistent than winds on land, making the offshore environment attractive for wind energy development. A large part of the offshore wind resource is however located in deep water, where floating turbines are the only economical way of harvesting the energy. The design of offshore floating wind turbines relies on the use of modeling tools that can simulate the entire coupled system behavior. At present, most of these tools include only first-order hydrodynamic theory. However, observations of supposed second-order hydrodynamic responses in wave-tank tests performed by the DeepCwind consortium suggest that second-order effects might be critical. In this paper, the methodology used by the oil and gas industry has been modified to apply to the analysis of floating wind turbines, and is used to assess the effect of second-order hydrodynamics on floating offshore wind turbines. The method relies on combined use of the frequency-domain tool WAMIT and the time-domain tool FAST. The proposed assessment method has been applied to two different floating wind concepts, a spar and a tension-leg-platform (TLP), both supporting the NREL 5-MW baseline wind turbine. Results showing the hydrodynamic forces and motion response for these systems are presented and analysed, and compared to aerodynamic effects.

  19. Operation and maintenance costs of offshore wind farms and potential multi-use platforms in the Dutch North Sea

    NARCIS (Netherlands)

    Rockmann, C.; Lagerveld, S.; Stavenuiter, J.

    2017-01-01

    Aquaculture within offshore wind farms has been identified as one of the many possibilities of smart use of marine space, leading to opportunities for innovative entrepreneurship. Offshore areas potentially pose less conflict with co-users than onshore. At the same time, offshore areas and offshore

  20. Asymmetrical Fault Analysis at the Offshore Network of HVDC connected Wind Power Plants

    DEFF Research Database (Denmark)

    Goksu, Omer; Cutululis, Nicolaos Antonio; Sorensen, Poul

    2017-01-01

    Short-circuit faults for HVDC connected Wind Power Plants (WPPs) have been studied mostly for dc link and onshore ac grid faults, while the offshore ac faults, especially asymmetrical faults, have been mostly omitted in the literature. Requirements related to the offshore asymmetrical faults have...

  1. Wake Influence on Dynamic Load Characteristics of Offshore Floating Wind Turbines

    DEFF Research Database (Denmark)

    Jeon, Minu; Lee, Soogab; Kim, Taeseong

    2016-01-01

    dynamic wake method, and unsteady vortex lattice method. The Offshore Code Comparison Collaboration Hywind model is chosen for offshore floating wind-turbine simulation. Results show that the blade-element momentum theory underestimates the rotor torque and speed. Moreover, although responses...

  2. Contribution of VSC-HVDC to Frequency Regulation of Power Systems With Offshore Wind Generation

    DEFF Research Database (Denmark)

    Liu, Hongzhi; Chen, Zhe

    2015-01-01

    capacitors of VSC-HVdc are controlled to absorb or release energy so as to provide frequency support. To further enhance the system frequency response, the frequency support from VSC-HVdc is also finely coordinated with that from offshore wind farm according to the latency of offshore wind farm responding......Modern large wind farms are required to provide frequency regulation service like conventional synchronous generation units. The frequency support capability of modern wind farms has been widely investigated and implemented. Remotely located large offshore wind farms are probably connected......, the stability and security of the power system will be put at risk, especially for those with high wind penetration. This paper proposes a coordinated control scheme to allow VSC-HVdc link to contribute to the system frequency regulation by adjusting its dc-link voltage. By means of this approach, the dc...

  3. Safety in offshore engineering an academic course covering safety in offshore wind

    NARCIS (Netherlands)

    Cerda Salzmann, D.J.

    2011-01-01

    Offshore projects are known for their challenging conditions, generally leading to high risks. Therefore no offshore project can go without a continuous and extensive assessment on safety issues. The Delft University of Technology is currently developing a course "Safety in Offshore Engineering"

  4. Short-term ecological effects of an offshore wind farm in the Dutch coastal zone; a compilation

    NARCIS (Netherlands)

    Lindeboom, H.J.; Kouwenhoven, H.J.; Bergman, M.J.N.; Bouma, S.; Brasseur, S.; Daan, R.; Fijn, R.C.; de Haan, D.; Dirksen, S.; van Hal, R.; Hille Ris Lambers, R.; ter Hofstede, R.; Krijgsveld, K.L.; Leopold, M.; Scheidat, M.

    2011-01-01

    The number of offshore wind farms is increasing rapidly, leading to questions about the environmental impact of such farms. In the Netherlands, an extensive monitoring programme is being executed at the first offshore wind farm (Offshore Windfarm Egmond aan Zee, OWEZ). This letter compiles the

  5. Frequency response variation of two offshore wind park transformers with different tap changer positions

    DEFF Research Database (Denmark)

    Arana Aristi, Iván; Holbøll, Joachim; Sørensen, T

    2010-01-01

    This paper presents the results of several sweep frequency response analysis (SFRA) measurements performed on two identical offshore wind farm transformers. A comparison is made between the transformers based on different recommended measurements and procedures, different measurement systems...

  6. GIS-BASED WIND FARM SITE SELECTION MODEL OFFSHORE ABU DHABI EMIRATE, UAE

    National Research Council Canada - National Science Library

    N. Saleous; S. Issa; J. Al Mazrouei

    2016-01-01

    .... This study aimed at assessing the viability of establishing wind farms offshore the Emirate of Abu Dhabi, UAE and to identify favourable sites for such farms using Geographic Information Systems (GIS...

  7. Wave Run-Up on Cylindrical and Cone Shaped Foundations for Offshore Wind Turbines

    DEFF Research Database (Denmark)

    De Vos, Leen; Frigaard, Peter; De Rouck, Julien

    2007-01-01

    During the last decade, several offshore wind-farms were built and offshore wind energy promises to be a suitable alternative to provide green energy. However, there are still some engineering challenges in placing the foundations of offshore wind turbines. For example, wave run-up and wave impacts...... cause unexpected damage to boat landing facilities and platforms. To assess the forces due to wave run-up, the distribution of run-up around the pile and the maximum run-up height need to be known. This article describes a physical model study of the run-up heights and run-up distribution on two shapes...... of foundations for offshore wind turbines, including both regular and irregular waves. The influence of wave steepness, wave height and water depth on run-up is investigated. The measured run-up values are compared with applicable theories and previous experimental studies predicting run-up on a circular pile...

  8. Challenges in Simulation of Aerodynamics, Hydrodynamics, and Mooring-Line Dynamics of Floating Offshore Wind Turbines

    Energy Technology Data Exchange (ETDEWEB)

    Matha, D.; Schlipf, M.; Cordle, A.; Pereira, R.; Jonkman, J.

    2011-10-01

    This paper presents the current major modeling challenges for floating offshore wind turbine design tools and describes aerodynamic and hydrodynamic effects due to rotor and platform motions and usage of non-slender support structures.

  9. Monitoring and Mitigation Alternatives for Protection of North Atlantic Right Whales during Offshore Wind Farm Installation

    Energy Technology Data Exchange (ETDEWEB)

    Carlson, Thomas J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Halvorsen, Michele B. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Matzner, Shari [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Copping, Andrea E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Stavole, Jessica [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2012-09-01

    Progress report on defining and determining monitoring and mitigation measures for protecting North Atlantic Right Whales from the effects of pile driving and other activities associated with installation of offshore wind farms.

  10. Technological learning in offshore wind energy: Different roles of the government

    NARCIS (Netherlands)

    Smit, T.; Junginger, M.; Smits, R.E.H.M.

    2007-01-01

    Offshore wind energy is a promising source of renewable electricity, even though its current costs prevent large-scale implementation. Technological learning has improved the technology and its economic performance already, and could result in significant further improvements. This study

  11. Loads Analysis of a Floating Offshore Wind Turbine Using Fully Coupled Simulation: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Jonkman, J. M.; Buhl, M. L., Jr.

    2007-06-01

    This paper presents the use of fully coupled aero-hydro-servo-elastic simulation tools to perform a loads analysis of a 5-MW offshore wind turbine supported by a barge with moorings, one of many promising floating platform concepts.

  12. Optimal Selection of AC Cables for Large Scale Offshore Wind Farms

    DEFF Research Database (Denmark)

    Hou, Peng; Hu, Weihao; Chen, Zhe

    2014-01-01

    The investment of large scale offshore wind farms is high in which the electrical system has a significant contribution to the total cost. As one of the key components, the cost of the connection cables affects the initial investment a lot. The development of cable manufacturing provides a vast...... choice space and a great opportunity to optimize the system cost while meets the operational requirements of the offshore wind farms and the connected power systems. In this paper, a new cost model for AC-cable is proposed and the optimal cable selection framework is established using the optimization...... platform in Matlab. A real offshore wind farm is chosen as the study case to demonstrate the proposed method. Furthermore, the optimization is also applied to an offshore wind farm under development. It can be observed from the results that the proposed optimal cable selection framework is an efficient...

  13. Mapping Operation and Maintenance Strategy for U.S. Offshore Wind Farms

    Energy Technology Data Exchange (ETDEWEB)

    Dewan, Ashish; Stehly, Tyler

    2017-06-22

    This presentation provides an overview of a collaborative effort between ECN and the National Renewable Energy Laboratory that focused on an operation and maintenance study of six offshore wind power plants in the United States.

  14. Fundaciones para turbinas eólicas costa afuera Foundations for offshore wind turbines

    National Research Council Canada - National Science Library

    Felipe Alberto Villalobos Jara

    2009-01-01

    .... Sin embargo, este no es el caso todavía en aplicaciones para aerogeneradores costa afuera.This paper describes the beginning and evolution of the now worldwide growing offshore wind energy industry...

  15. Optimal Power Transmission of Offshore Wind Power Using a VSC-HVdc Interconnection

    National Research Council Canada - National Science Library

    Miguel E. Montilla-DJesus; Santiago Arnaltes; Edgardo D. Castronuovo; David Santos-Martin

    2017-01-01

    High-voltage dc transmission based on voltage-source converter (VSC-HVdc) is quickly increasing its power rating, and it can be the most appropriate link for the connection of offshore wind farms (OWFs...

  16. IEA Wind Task 23, offshore wind technology and deployment. Subtask 1: Experience with critical deployment issues. Final technical report

    Energy Technology Data Exchange (ETDEWEB)

    Lemming, J.

    2010-10-15

    The final report for IEA Wind Task 23, Offshore Wind Energy Technology and Deployment, is made up of two separate reports: Subtask 1: Experience with Critical Deployment Issues and Subtask 2: Offshore Code Comparison Collaborative (OC3). The Subtask 1 report included here provides background information and objectives of Task 23. It specifically discusses ecological issues and regulation, electrical system integration and offshore wind, external conditions, and key conclusions for Subtask 1. A comprehensive approach to planning is needed that integrates impacts on ecology, the effects of electrical infrastructure, and the layout of wind farms. Governments, which usually finance ecological research, should disclose results for wide dissemination as they become available. As example the workshop held suggested that documents covering the issues like offshore wind energy legislation, Guidelines for EIAs and SEAs and best practices need to be produced and distributed on a regular basis, as ecological research progresses and experience from the planning and operation of existing wind farms emerges. Research should help strike the balance between optimum regulation and the need to get projects up and running. Such research is needed to increase understanding of offshore wind metrology and its impact on electrical power fluctuations. More work is needed to develop special grid code and standards for offshore. The transient behavior of large cable installations (switching / harmonic/ Behavior and modeling of large HV cable systems) must be better understood. Connection and control systems must be developed for large offshore wind farms. Work is needed to develop the technical architecture of offshore wind grid systems. Public access to measurements (e.g., turbine power output, meteorological masts, buoys) is important, especially for model validation. Determining wake effects is currently the most important challenge in wind engineering. Emphasis should be put into

  17. Jobs and Economic Development Impact (JEDI) Model: Offshore Wind User Reference Guide

    Energy Technology Data Exchange (ETDEWEB)

    Lantz, E.; Goldberg, M.; Keyser, D.

    2013-06-01

    The Offshore Wind Jobs and Economic Development Impact (JEDI) model, developed by NREL and MRG & Associates, is a spreadsheet based input-output tool. JEDI is meant to be a user friendly and transparent tool to estimate potential economic impacts supported by the development and operation of offshore wind projects. This guide describes how to use the model as well as technical information such as methodology, limitations, and data sources.

  18. Simulation of a rectifier malfunction on an offshore wind system with HVDC transmission

    OpenAIRE

    Melicio, Rui

    2015-01-01

    A new integrated mathematical model for the simulation of an offshore wind system having a rectifier input voltage malfunction at one phase is presented in this paper. The mathematical model considers an offshore variable-speed wind turbine on a floating platform, equipped with a permanent magnet synchronous generator using full-power three-level converter to inject energy into the electric network, through a high voltage direct current transmission submarine cable. The model for the drive tr...

  19. High-resolution computational algorithms for simulating offshore wind turbines and farms: Model development and validation

    Energy Technology Data Exchange (ETDEWEB)

    Calderer, Antoni [Univ. of Minnesota, Minneapolis, MN (United States); Yang, Xiaolei [Stony Brook Univ., NY (United States); Angelidis, Dionysios [Univ. of Minnesota, Minneapolis, MN (United States); Feist, Chris [Univ. of Minnesota, Minneapolis, MN (United States); Guala, Michele [Univ. of Minnesota, Minneapolis, MN (United States); Ruehl, Kelley [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Guo, Xin [Univ. of Minnesota, Minneapolis, MN (United States); Boomsma, Aaron [Univ. of Minnesota, Minneapolis, MN (United States); Shen, Lian [Univ. of Minnesota, Minneapolis, MN (United States); Sotiropoulos, Fotis [Stony Brook Univ., NY (United States)

    2015-10-30

    The present project involves the development of modeling and analysis design tools for assessing offshore wind turbine technologies. The computational tools developed herein are able to resolve the effects of the coupled interaction of atmospheric turbulence and ocean waves on aerodynamic performance and structural stability and reliability of offshore wind turbines and farms. Laboratory scale experiments have been carried out to derive data sets for validating the computational models.

  20. Responses of two marine top predators to an offshore wind farm.

    Science.gov (United States)

    Vallejo, Gillian C; Grellier, Kate; Nelson, Emily J; McGregor, Ross M; Canning, Sarah J; Caryl, Fiona M; McLean, Nancy

    2017-11-01

    Quantifying the likely effects of offshore wind farms on wildlife is fundamental before permission for development can be granted by any Determining Authority. The effects on marine top predators from displacement from important habitat are key concerns during offshore wind farm construction and operation. In this respect, we present evidence for no significant displacement from a UK offshore wind farm for two broadly distributed species of conservation concern: common guillemot ( Uria aalge ) and harbor porpoise ( Phocoena phocoena ). Data were collected during boat-based line transect surveys across a 360 km 2 study area that included the Robin Rigg offshore wind farm. Surveys were conducted over 10 years across the preconstruction, construction, and operational phases of the development. Changes in guillemot and harbor porpoise abundance and distribution in response to offshore wind farm construction and operation were estimated using generalized mixed models to test for evidence of displacement. Both common guillemot and harbor porpoise were present across the Robin Rigg study area throughout all three development phases. There was a significant reduction in relative harbor porpoise abundance both within and surrounding the Robin Rigg offshore wind farm during construction, but no significant difference was detected between the preconstruction and operational phases. Relative common guillemot abundance remained similar within the Robin Rigg offshore wind farm across all development phases. Offshore wind farms have the potential to negatively affect wildlife, but further evidence regarding the magnitude of effect is needed. The empirical data presented here for two marine top predators provide a valuable addition to the evidence base, allowing future decision making to be improved by reducing the uncertainty of displacement effects and increasing the accuracy of impact assessments.

  1. RAMSI management model and evaluation criteria for Nordic offshore wind asset

    Energy Technology Data Exchange (ETDEWEB)

    Tiusanen, R.; Jaennes, J. [VTT Technical Research Centre of Finland, Espoo (Finland); Liyanage, J. P. [Univ. of Stavanger, Center for Industrial Asset Management (Norway)

    2012-07-01

    The offshore wind energy sector is in the early stages of development, but it is growing fast. Due to the European Union's renewable-energy and climate goals along with national legislation, the offshore wind sector will develop strongly over the coming years in Europe. In the offshore wind energy sector, there are many different wind-turbine designs ranging from traditional mono pile structures to floating platforms, depending on the water depth. Today, most offshore turbines are based on onshore turbine designs, and turbine technology continues to develop incrementally. At the same time, there is strong demand in the market for new, innovative designs for offshore wind turbines whose main focus is reliability and cost efficiency. For floating offshore wind turbine designs, there may be new types of uncertainty and system risks compared with onshore wind turbines. Wind turbines in cold climates, such as those experienced in the Nordic countries, may be exposed to extreme conditions, such as formation of ice or very low temperatures that are outside the design limits of standard wind turbines. In the offshore wind energy sector, specification, implementation and verification of the so-called R&M's (Reliability, Availability, Maintainability, Safety and Inspect ability) requirements during development work are important for companies delivering wind turbines, from the perspective of system integrity. Decisions made before the formal design phase strongly determine the costs and benefits gained during the whole life cycle of a wind turbine. The benefits of implementing the R&M's program include support with investment decisions, cost management, improved management of resource requirements, systematic support with development and implementation of products, and integration of dependability and safety requirements. This publication outlines a model for managing R&M's factors during the conceptual design phase of an offshore wind turbine. The model

  2. Review of Laterally Loaded Monopiles Employed as the Foundation for Offshore Wind Turbines

    DEFF Research Database (Denmark)

    Sørensen, Søren Peder Hyldal; Brødbæk, Kristian Thoustrup; Møller, Martin

    Monopiles are often used foundation concepts for offshore wind turbine converters. These piles are highly subjected to latereal loads and overturning moments due to wind and wave forces. Typically, monopiles with diameters of 4 to 6 m and embedded pile lenghts of 15 to 30 m are necessart. In curr......Monopiles are often used foundation concepts for offshore wind turbine converters. These piles are highly subjected to latereal loads and overturning moments due to wind and wave forces. Typically, monopiles with diameters of 4 to 6 m and embedded pile lenghts of 15 to 30 m are necessart...

  3. Vessel fleet size and mix for maintenance of offshore wind farms: A stochastic approach

    OpenAIRE

    Gundegjerde, Christian; Halvorsen, Ina Blomseth

    2012-01-01

    In recent years the global installed capacity of offshore wind has increased rapidly, due to the world’s green electricity demand. Increasing developments in the offshore wind sector has led to fewer possible locations for new wind farms, forcing the developers to move further and further away from shore. This shift from near-shore to far-shore wind farm locations, increases the complexity and costs of executing operations and maintenance, which can account for 25% of the production cost of p...

  4. Power Flow Analysis of HVAC and HVDC Transmission Systems for Offshore WindParks

    DEFF Research Database (Denmark)

    da Silva, Filipe Miguel Faria; Castro, Rui

    2009-01-01

    As the onshore wind resource is running shorter, wind power promoters are paying attention to the offshore resources. As in most cases there is no load offshore, wind power must be transmitted to the main land. To do so, two options are available: HVAC and HVDC transmission systems. In this paper...... that HVAC solution is limited by the distance to shore and by the wind transmitted power. HVDC options do not show these limitations, but are more expensive and more delicate to deal with, because there is a lack of operational experience, so far....

  5. Case Study of Integrating an Offshore Wind Farm with Offshore Oil and Gas Platforms and with an Onshore Electrical Grid

    Directory of Open Access Journals (Sweden)

    Wei He

    2013-01-01

    Full Text Available This research project explored the technical feasibility of utilizing an offshore wind farm as a supplementary power source to several electrical grids of offshore oil and gas platforms and providing surplus power to an onshore grid. Three case studies comprising wind farms rated at 20 MW, 100 MW, and 1000 MW have been studied with the focus on (i the operation benefits of CO2/NOx emission reduction, (ii the electrical grid stability, and (iii the technical implementation feasibility. The proposed 20 MW, 100 MW, and 1000 MW wind farm cases are theoretically feasible in terms of the selected technical criteria, although further detailed design operational studies, and economical analysis are required.

  6. Potential Impacts of Offshore Wind Farms on North Sea Stratification.

    Science.gov (United States)

    Carpenter, Jeffrey R; Merckelbach, Lucas; Callies, Ulrich; Clark, Suzanna; Gaslikova, Lidia; Baschek, Burkard

    2016-01-01

    Advances in offshore wind farm (OWF) technology have recently led to their construction in coastal waters that are deep enough to be seasonally stratified. As tidal currents move past the OWF foundation structures they generate a turbulent wake that will contribute to a mixing of the stratified water column. In this study we show that the mixing generated in this way may have a significant impact on the large-scale stratification of the German Bight region of the North Sea. This region is chosen as the focus of this study since the planning of OWFs is particularly widespread. Using a combination of idealised modelling and in situ measurements, we provide order-of-magnitude estimates of two important time scales that are key to understanding the impacts of OWFs: (i) a mixing time scale, describing how long a complete mixing of the stratification takes, and (ii) an advective time scale, quantifying for how long a water parcel is expected to undergo enhanced wind farm mixing. The results are especially sensitive to both the drag coefficient and type of foundation structure, as well as the evolution of the pycnocline under enhanced mixing conditions-both of which are not well known. With these limitations in mind, the results show that OWFs could impact the large-scale stratification, but only when they occupy extensive shelf regions. They are expected to have very little impact on large-scale stratification at the current capacity in the North Sea, but the impact could be significant in future large-scale development scenarios.

  7. Potential Impacts of Offshore Wind Farms on North Sea Stratification.

    Directory of Open Access Journals (Sweden)

    Jeffrey R Carpenter

    Full Text Available Advances in offshore wind farm (OWF technology have recently led to their construction in coastal waters that are deep enough to be seasonally stratified. As tidal currents move past the OWF foundation structures they generate a turbulent wake that will contribute to a mixing of the stratified water column. In this study we show that the mixing generated in this way may have a significant impact on the large-scale stratification of the German Bight region of the North Sea. This region is chosen as the focus of this study since the planning of OWFs is particularly widespread. Using a combination of idealised modelling and in situ measurements, we provide order-of-magnitude estimates of two important time scales that are key to understanding the impacts of OWFs: (i a mixing time scale, describing how long a complete mixing of the stratification takes, and (ii an advective time scale, quantifying for how long a water parcel is expected to undergo enhanced wind farm mixing. The results are especially sensitive to both the drag coefficient and type of foundation structure, as well as the evolution of the pycnocline under enhanced mixing conditions-both of which are not well known. With these limitations in mind, the results show that OWFs could impact the large-scale stratification, but only when they occupy extensive shelf regions. They are expected to have very little impact on large-scale stratification at the current capacity in the North Sea, but the impact could be significant in future large-scale development scenarios.

  8. Floating Offshore Wind in Oregon: Potential for Jobs and Economic Impacts from Two Future Scenarios

    Energy Technology Data Exchange (ETDEWEB)

    Jimenez, Tony [National Renewable Energy Lab. (NREL), Golden, CO (United States); Keyser, David [National Renewable Energy Lab. (NREL), Golden, CO (United States); Tegen, Suzanne [National Renewable Energy Lab. (NREL), Golden, CO (United States); Speer, Bethany [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2016-05-01

    Construction of the first offshore wind power plant in the United States began in 2015, off the coast of Rhode Island, using fixed platform structures that are appropriate for shallow seafloors, like those located off of the East Coast and mid-Atlantic. However, floating platforms, which have yet to be deployed commercially, will likely need to anchor to the deeper seafloor if deployed off of the West Coast. To analyze the employment and economic potential for floating offshore wind along the West Coast, the Bureau of Ocean Energy Management (BOEM) commissioned the National Renewable Energy Laboratory (NREL) to analyze two hypothetical, large-scale deployment scenarios for Oregon: 5,500 megawatts (MW) of offshore wind deployment in Oregon by 2050 (Scenario A), and 2,900 MW of offshore wind by 2050 (Scenario B). These levels of deployment could power approximately 1,600,000 homes (Scenario A) or 870,000 homes (Scenario B). Offshore wind would contribute to economic development in Oregon in the near future, and more substantially in the long term, especially if equipment and labor are sourced from within the state. According to the analysis, over the 2020-2050 period, Oregon floating offshore wind facilities could support 65,000-97,000 job-years and add $6.8 billion-$9.9 billion to the state GDP (Scenario A).

  9. Effects of Second-Order Hydrodynamic Forces on Floating Offshore Wind Turbines

    Energy Technology Data Exchange (ETDEWEB)

    Duarte, T.; Sarmento, A. J. N. A.; Jonkman, J.

    2014-04-01

    Relative to first-order, second-order wave-excitation loads are known to cause significant motions and additional loads in offshore oil and gas platforms. The design of floating offshore wind turbines was partially inherited from the offshore oil and gas industry. Floating offshore wind concepts have been studied with powerful aero-hydro-servo-elastic tools; however, most of the existing work on floating offshore wind turbines has neglected the contribution of second-order wave-excitation loads. As a result, this paper presents a computationally efficient methodology to consider these loads within FAST, a wind turbine computer-aided engineering tool developed by the National Renewable Energy Laboratory. The method implemented was verified against the commercial OrcaFlex tool, with good agreement, and low computational time. A reference floating offshore wind turbine was studied under several wind and wave load conditions, including the effects of second-order slow-drift and sum-frequency loads. Preliminary results revealed that these loads excite the turbine's natural frequencies, namely the surge and pitch natural frequencies.

  10. Developing an Indicator System for Measuring the Social Sustainability of Offshore Wind Power Farms

    Directory of Open Access Journals (Sweden)

    Tzay-An Shiau

    2016-05-01

    Full Text Available Taiwan’s government has promoted investment in an offshore wind power farm, and local fishermen have protested. A social impact assessment (SIA has examined the impact of the proposed offshore wind power farm on all stakeholders. The main objective of the present study was to develop an indicator system for measuring the social sustainability of offshore wind power farms; this study also reports on the particular case of Taiwan’s offshore wind power project. This study began by defining 35 social sustainability indicators and selecting 23 representative indicators by using rough set theory. Subsequently, 14 key indicators were constructed using the social construction of technology (SCOT method. Finally, we developed a social impact index for evaluating the social sustainability of offshore wind power farms by using the analytic network process and Dempster-Shafer theory. Our social impact index yields a total score of 0.149 for Taiwan’s pilot offshore wind power project; this result indicates that the pilot project is socially sustainable. A substantial contradiction exists between the fishermen’s protest and the results of the social impact assessment. The findings can assist the government in building a coordination platform for the investors and the fishermen. Government regulation is necessary to set boundaries for fishing areas that protect both the fishermen’s and investors’ rights.

  11. Fatigue distribution optimization for offshore wind farms using intelligent agent control

    DEFF Research Database (Denmark)

    Zhao, Rongyong; Shen, Wen Zhong; Knudsen, Torben

    2012-01-01

    A novel control approach is proposed to optimize the fatigue distribution of wind turbines in a large‐scale offshore wind farm on the basis of an intelligent agent theory. In this approach, each wind turbine is considered to be an intelligent agent. The turbine at the farm boundary communicates...... coefficient for every wind turbine. The optimization is constrained such that the average fatigue for every turbine is smaller than what would be achieved by conventional dispatch and such that the total power loss of the wind farm is restricted to a few percent of the total power. This intelligent agent...... control approach is verified through the simulation of wind data from the Horns Rev offshore wind farm. The results illustrate that intelligent agent control is a feasible way to optimize fatigue distribution in wind farms, which may reduce the maintenance frequency and extend the service life of large...

  12. Service and Maintenance - Lillgrund Offshore Wind Farm. Lillgrund Pilot Project

    Energy Technology Data Exchange (ETDEWEB)

    Soederberg, David; Weisbach, Henrik (Vattenfall Vindkraft AB, Stockholm (Sweden))

    2008-11-15

    This report aims to provide information of, and experiences from, service and maintenance of Lillgrund Offshore Wind Farm. The report deals with operation and maintenance (O and M) during construction, commissioning and the first three months of operation. Focus has been to describe the organization and cooperation between Vattenfall and Siemens. Experiences have been collected by interviews with representatives from Siemens and Vattenfall. The O and M strategy defined by Lillgrund's service and maintenance contract are based on a gradual take over of O and M. Siemens will be responsible for maintenance of Lillgrund during the first five years. During this five-year period, Vattenfall will build up its own maintenance organization for Lillgrund. The first three years, Vattenfall's technicians are supposed to form 30 % of the total number of maintenance technicians. The fourth and fifth year, the corresponding amount should be 50 %. During daytime, Lillgrund is operated locally. During nights and weekends, it is operated remotely by Vattenfall's operating centre in Esbjerg. The major O and M experience from Lillgrund is the need for good administrative and technical information systems. These systems should be implemented as soon as possible because of the large amounts of documentation that are created during the commissioning phase. The technical information systems must be able to present historic data of measurements in order to see trends and analyse faults

  13. Active motion and load control of floating offshore wind turbines

    Science.gov (United States)

    Jalili, Kaveh

    The research in this thesis is focused on stabilization and load reduction of floating offshore wind turbine (FOWT) structures for both the fore-aft (pitch) and side-to-side (roll) directions. Based on the Tuned Mass Damper (TMD) and Active Vane concepts recently proposed, two composite actuation schemes are investigated. The first scheme is to apply the horizontal vane and vertical vane to platform pitch and roll, respectively, resulting in the so-called Double Vane Actuation (DVA) scheme. The second scheme is the combination of the TMD based pitch control and active vertical vane based roll control, resulting in the so-called Hybrid Actuation (HA) scheme. Simulation results of DVA show great reductions of motions and loads in the fore-aft and side-to-side directions. Performance of HA is investigated by extensive simulations based on the IEC61400-3 standard and results show significant and consistent motions and loads reductions in both FA and SS directions.

  14. Proposal of a methodology for the design of offshore wind farms

    Science.gov (United States)

    Esteban, Dolores; Diez, J. Javier; Santos Lopez, J.; Negro, Vicente

    2010-05-01

    In fact, the wind power installed in the sea is still very scarce, with only 1,500 megawatts in operation in the middle of 2009. Although the first offshore wind farm experiment took place in 1990, the facilities built up to now have been mainly pilot projects. These previous statements confirm the incipient state of offshore wind power, Anyway, in this moment this technology is being strongly pushed, especially by the governments of some countries - like the United Kingdom, Germany, etc. - which is due above all to the general commitments made to reduce the emission of greenhouses gases. All of these factors lead to predict a promising future for offshore wind power. Nevertheless, it has not been still established a general methodology for the design and the management of this kind of installations. This paper includes some of the results of a research project, which consists on the elaboration of a methodology to enable the optimization of the global process of the operations leading to the implantation of offshore wind facilities. The proposed methodology allows the planning of offshore wind projects according to an integral management policy, enabling not only technical and financial feasibility of the offshore wind project to be achieved, but also respect for the environment. For that, it has been necessary to take into account multiple factors, including the territory, the terrain, the physical-chemical properties of the contact area between the atmosphere and the ocean, the dynamics resulting in both as a consequence of the Earth's behaviour as a heat machine, external geodynamics, internal geodynamics, planetary dynamics, biokenosis, the legislative and financial framework, human activities, wind turbines, met masts, electric substations and lines, foundations, logistics and the project's financial profitability. For its validation, this methodology has been applied to different offshore wind farms in operation.

  15. Extreme Value Predictions for Wave- and Wind-induced Loads on Floating Offshore Wind Turbines using FORM

    DEFF Research Database (Denmark)

    Joensen, Sunvard; Jensen, Jørgen Juncher; Mansour, Alaa E.

    2007-01-01

    probable wave episodes leading to given re-sponses. As an example the motions of floating foundations for offshore wind turbines are analysed taking into consid-eration both the wave and wind induced loads and con-sidering different mooring systems. The possible large horizontal motions make it important...

  16. Flap controllers applied on the OffshoreWindChina (OWC) 5MW reference wind turbine for Chinese typhoon conditions

    DEFF Research Database (Denmark)

    Barlas, Athanasios

    The report describes the development of flap controllers applied on the OffshoreWindChina (OWC) 5MW reference wind turbine for Chinese typhoon conditions. Optimal flap controllers are designed and tuned based on linear aeroelastic models from HawcStab2. The controllers are evaluated in normal......, parked and storm conditions, targeting the alleviation of fatigue and extreme loads....

  17. Efficient preliminary floating offshore wind turbine design and testing methodologies and application to a concrete spar design

    National Research Council Canada - National Science Library

    Matha, Denis; Sandner, Frank; Molins, Climent; Campos, Alexis; Cheng, Po Wen

    2015-01-01

    The current key challenge in the floating offshore wind turbine industry and research is on designing economic floating systems that can compete with fixed-bottom offshore turbines in terms of levelized cost of energy...

  18. Offshore Code Comparison Collaboration within IEA Wind Annex XXIII: Phase III Results Regarding Tripod Support Structure Modeling

    Energy Technology Data Exchange (ETDEWEB)

    Nichols, J.; Camp, T.; Jonkman, J.; Butterfield, S.; Larsen, T.; Hansen, A.; Azcona, J.; Martinez, A.; Munduate, X.; Vorpahl, F.; Kleinhansl, S.; Kohlmeier, M.; Kossel, T.; Boker, C.; Kaufer, D.

    2009-01-01

    Offshore wind turbines are designed and analyzed using comprehensive simulation codes. This paper describes the findings of code-to-code verification activities of the IEA Offshore Code Comparison Collaboration.

  19. A proposed national wind power R and D program. [offshore wind power system for electric energy supplies

    Science.gov (United States)

    Heronemus, W.

    1973-01-01

    An offshore wind power system is described that consists of wind driven electrical dc generators mounted on floating towers in offshore waters. The output from the generators supplies underwater electrolyzer stations in which water is converted into hydrogen and oxygen. The hydrogen is piped to shore for conversion to electricity in fuel cell stations. It is estimated that this system can produce 159 x 10 to the ninth power kilowatt-hours per year. It is concluded that solar energy - and that includes wind energy - is the only way out of the US energy dilemma in the not too distant future.

  20. Effect of Second-Order Hydrodynamics on a Floating Offshore Wind Turbine

    Energy Technology Data Exchange (ETDEWEB)

    Roald, L.; Jonkman, J.; Robertson, A.

    2014-05-01

    The design of offshore floating wind turbines uses design codes that can simulate the entire coupled system behavior. At the present, most codes include only first-order hydrodynamics, which induce forces and motions varying with the same frequency as the incident waves. Effects due to second- and higher-order hydrodynamics are often ignored in the offshore industry, because the forces induced typically are smaller than the first-order forces. In this report, first- and second-order hydrodynamic analysis used in the offshore oil and gas industry is applied to two different wind turbine concepts--a spar and a tension leg platform.

  1. Dynamic Reactive Power Control in Offshore HVDC Connected Wind Power Plants

    DEFF Research Database (Denmark)

    Sakamuri, Jayachandra N.; Cutululis, Nicolaos Antonio; Rather, Zakir Hussain

    2016-01-01

    This paper presents a coordinated reactive power control for a HVDC connected cluster of offshore wind power plants (WPPs). The reactive power reference for the WPP cluster is estimated by an optimization algorithm aiming at minimum active power losses in the offshore AC Grid. For each optimal......, such as wind turbine (WT) terminal, collector cable, and export cable, on the dynamic voltage profile of the offshore grid is investigated. Furthermore, the dynamic reactive power contribution from WTs from different WPPs of the cluster for such faults has also been studied....

  2. Inertial Response of an Offshore Wind Power Plant with HVDC-VSC

    Energy Technology Data Exchange (ETDEWEB)

    Preciado, V.; Gevorgian, Vahan; Muljadi, Eduard; Madrigal, M.

    2017-01-05

    This paper analyzes the inertial response of an offshore wind power plant (WPP) to provide ancillary services to the power system grid. The WPP is connected to a high-voltage direct-current voltage source converter HVDC-VSC to deliver the power to the onshore substation. The wind turbine generator (WTG) used is a doubly-fed induction generator (Type 3 WTG). In this paper we analyze a control method for the WTGs in an offshore WPP to support the grid and contribute ancillary services to the power system network. Detailed time domain simulations will be conducted to show the transient behavior of the inertial response of an offshore WPP.

  3. Preliminary test of the prototype modular cryostat for a 10 MW offshore superconducting wind turbine

    Science.gov (United States)

    Sun, Jiuce; Ramalingam, R.; Sanz, Santiago; Neumann, Holger

    2017-02-01

    The SUPerconducting Reliable lightweight And more POWERful offshore wind turbine (SUPRAPOWER), an EU FP7 funded research project, are under development for an innovative superconducting 10 MW class offshore wind turbine. Due to the requirements of handling, maintenance, reliability of long term and offshore operation, the cryostats are divided in two major parts: the modular cryostat able to accommodate a single coil and a thermal collector that links all the modules. The prototype modular cryostat was designed, manufactured and assembled in Karlsruhe Institute of Technology (KIT). The paper reports preliminary test results of proto-type modular cryostat with a two-stage Gifford-McMahon (GM) cryocooler.

  4. Fatigue and Serviceability Limit State Model Basis for Assessment of Offshore Wind Energy Converters

    DEFF Research Database (Denmark)

    Thöns, Sebastian; Faber, M. H.; Rücker, W.

    2012-01-01

    This paper develops the models for the structural performance of the loading and probabilistic characterization for the fatigue and the serviceability limit states for the support structure of offshore wind energy converters. These models and a sensitivity study are part of a risk based assessment...... al. ("Ultimate Limit State Model Basis for Assessment of Offshore Wind Energy Con-verters," ASME J. Offshore Mech. Arct. Eng.), the model basis for the assessment is completed. The process of establishing and analyzing such a model basis contributes to a detailed understanding of the deterministic...

  5. Design and Control of A DC Grid for Offshore Wind Farms

    DEFF Research Database (Denmark)

    Deng, Fujin

    , the high-voltage direct current (HVDC) is attractive. In addition, the DC grid may also be interested for interconnecting the wind turbines in the collection level. As a consequence, a DC grid can be established for the offshore wind farm, where the wind power collection system and power transmission...... system both adopt DC technology. S far, the existing grid codes for wind turbines are mainly focused on AC system. Therefore, the faults analysis in the DC grid and the appropriate fault protections are required for the DC grid. This thesis focuses on the design and control of the DC grid for offshore...... is proposed and designed for the HVDC system. Afterwards, the redundancy of the HVDC system under cable faults is studied, and a fault ride-through strategy is proposed for the DC grid under cable faults. Throughout the thesis, the DC grid for offshore wind farms examples are modeled with the professional...

  6. Solving the Turbine Positioning Problem for Large Offshore Wind Farms by Simulated Annealing

    DEFF Research Database (Denmark)

    Rivas, Rajai Aghabi; Clausen, Jens; Hansen, Kurt Schaldemose

    2009-01-01

    The current paper is concerned with determining the optimal layout of the turbines inside large offshore wind farms by means of an optimization algorithm. We call this the Turbine Positioning Problem. To achieve this goal a simulated annealing algorithm has been devised, where three types of local...... represents an effective strategy for the wind turbine positioning problem. The findings enable the comparison of the optimized and the grid layouts and the study of the wake differences between these configurations. It is seen that for very large offshore wind farms the difference in wake losses...... search operations are performed recursively until the system converges. The effectiveness of the proposed algorithm is demonstrated on a suite of real life test cases, including Horns Rev offshore wind farm. The results are verified using a commercial wind resource software indicating that this method...

  7. Potential Offshore Wind Energy Areas in California: An Assessment of Locations, Technology, and Costs

    Energy Technology Data Exchange (ETDEWEB)

    Musial, Walter [National Renewable Energy Lab. (NREL), Golden, CO (United States); Beiter, Philipp [National Renewable Energy Lab. (NREL), Golden, CO (United States); Tegen, Suzanne [National Renewable Energy Lab. (NREL), Golden, CO (United States); Smith, Aaron [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2016-12-01

    This report summarizes a study of possible offshore wind energy locations, technologies, and levelized cost of energy in the state of California between 2015 and 2030. The study was funded by the U.S. Department of the Interior's Bureau of Ocean Energy Management (BOEM), the federal agency responsible for regulating renewable energy development on the Outer Continental Shelf. It is based on reference wind energy areas where representative technology and performance characteristics were evaluated. These reference areas were identified as sites that were suitable to represent offshore wind cost and technology based on physical site conditions, wind resource quality, known existing site use, and proximity to necessary infrastructure. The purpose of this study is to assist energy policy decision-making by state utilities, independent system operators, state government officials and policymakers, BOEM, and its key stakeholders. The report is not intended to serve as a prescreening exercise for possible future offshore wind development.

  8. MARE-WINT. New Materials and Reliability in Offshore Wind Turbine Technology

    DEFF Research Database (Denmark)

    This book provides a holistic, interdisciplinary overview of offshore wind energy, and is a must-read for advanced researchers. Topics, from the design and analysis of future turbines, to the decommissioning of wind farms, are covered. The scope of the work ranges from analytical, numerical...... and experimental advancements in structural and fluid mechanics, to novel developments in risk, safety & reliability engineering for offshore wind. The core objective of the current work is to make offshore wind energy more competitive, by improving the reliability, and operations and maintenance (O&M) strategies...... of wind turbines. The research was carried out under the auspices of the EU-funded project, MARE-WINT. The work seeks to bridge the gap between research and a rapidly-evolving industry....

  9. Evaluation of the wind direction uncertainty and its impact on wake modeling at the Horns Rev offshore wind farm

    DEFF Research Database (Denmark)

    Gaumond, M.; Réthoré, Pierre-Elouan; Ott, Søren

    2014-01-01

    Accurately quantifying wind turbine wakes is a key aspect of wind farm economics in large wind farms. This paper introduces a new simulation post-processing method to address the wind direction uncertainty present in the measurements of the Horns Rev offshore wind farm. This new technique replaces...... the traditional simulations performed with the 10 min average wind direction by a weighted average of several simulations covering a wide span of directions. The weights are based on a normal distribution to account for the uncertainty from the yaw misalignment of the reference turbine, the spatial variability...... of the wind direction inside the wind farm and the variability of the wind direction within the averaging period. The results show that the technique corrects the predictions of the models when the simulations and data are averaged over narrow wind direction sectors. In addition, the agreement of the shape...

  10. Assessment of Offshore Wind Energy Leasing Areas for the BOEM New Jersey Wind Energy Area

    Energy Technology Data Exchange (ETDEWEB)

    Musial, W.; Elliott, D.; Fields, J.; Parker, Z.; Scott, G.; Draxl, C.

    2013-10-01

    The National Renewable Energy Laboratory (NREL), under an interagency agreement with the U.S. Department of the Interior's Bureau of Ocean Energy Management (BOEM), is providing technical assistance to identify and delineate leasing areas for offshore wind energy development within the Atlantic Coast Wind Energy Areas (WEAs) established by BOEM. This report focuses on NREL's development and evaluation of the delineations for the New Jersey (NJ) WEA. The overarching objective of this study is to develop a logical process by which the New Jersey WEA can be subdivided into non-overlapping leasing areas for BOEM's use in developing an auction process in a renewable energy lease sale. NREL identified a selection of leasing areas and proposed delineation boundaries within the established NJ WEA. The primary output of the interagency agreement is this report, which documents the methodology, including key variables and assumptions, by which the leasing areas were identified and delineated.

  11. A study of current maintenance challenges in a large offshore wind farm

    DEFF Research Database (Denmark)

    Petersen, Kristian Rasmus; Madsen, Erik Skov; Bilberg, Arne

    The aim of the present research project is to obtain a better understanding of the operations and maintenance (O&M) processes that are performed in the offshore wind energy sector. So far, the focus on O&M of offshore wind parks has been very limited and is currently in its early phase....... A comparative study of the existing life cycle analysis of offshore wind parks found that the majority of these analyses do not include an O&M aspect in their calculations. In the present study the current O&M processes of a large offshore wind park is investigated. The wind park is operating in one of the most...... harsh and stochastic environments in the North Sea. The wind park is operated by one of Europe’s largest energy companies and the study gives an insight and a deeper understanding of the challenges of operating and maintaining a large offshore wind farm under very rough sea conditions. The main method...

  12. Numerical investigation of interactions between marine atmospheric boundary layer and offshore wind farm

    Science.gov (United States)

    Lyu, Pin; Chen, Wenli; Li, Hui; Shen, Lian

    2017-11-01

    In recent studies, Yang, Meneveau & Shen (Physics of Fluids, 2014; Renewable Energy, 2014) developed a hybrid numerical framework for simulation of offshore wind farm. The framework consists of simulation of nonlinear surface waves using a high-order spectral method, large-eddy simulation of wind turbulence on a wave-surface-fitted curvilinear grid, and an actuator disk model for wind turbines. In the present study, several more precise wind turbine models, including the actuator line model, actuator disk model with rotation, and nacelle model, are introduced into the computation. Besides offshore wind turbines on fixed piles, the new computational framework has the capability to investigate the interaction among wind, waves, and floating wind turbines. In this study, onshore, offshore fixed pile, and offshore floating wind farms are compared in terms of flow field statistics and wind turbine power extraction rate. The authors gratefully acknowledge financial support from China Scholarship Council (No. 201606120186) and the Institute on the Environment of University of Minnesota.

  13. Unsteady aerodynamic analysis for offshore floating wind turbines under different wind conditions.

    Science.gov (United States)

    Xu, B F; Wang, T G; Yuan, Y; Cao, J F

    2015-02-28

    A free-vortex wake (FVW) model is developed in this paper to analyse the unsteady aerodynamic performance of offshore floating wind turbines. A time-marching algorithm of third-order accuracy is applied in the FVW model. Owing to the complex floating platform motions, the blade inflow conditions and the positions of initial points of vortex filaments, which are different from the fixed wind turbine, are modified in the implemented model. A three-dimensional rotational effect model and a dynamic stall model are coupled into the FVW model to improve the aerodynamic performance prediction in the unsteady conditions. The effects of floating platform motions in the simulation model are validated by comparison between calculation and experiment for a small-scale rigid test wind turbine coupled with a floating tension leg platform (TLP). The dynamic inflow effect carried by the FVW method itself is confirmed and the results agree well with the experimental data of a pitching transient on another test turbine. Also, the flapping moment at the blade root in yaw on the same test turbine is calculated and compares well with the experimental data. Then, the aerodynamic performance is simulated in a yawed condition of steady wind and in an unyawed condition of turbulent wind, respectively, for a large-scale wind turbine coupled with the floating TLP motions, demonstrating obvious differences in rotor performance and blade loading from the fixed wind turbine. The non-dimensional magnitudes of loading changes due to the floating platform motions decrease from the blade root to the blade tip. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

  14. Challenges and solutions of remote sensing at offshore wind energy developments.

    Science.gov (United States)

    Kelly, T A; West, T E; Davenport, J K

    2009-11-01

    Radar is becoming an important tool used to gather data on bird and bat activity at proposed and existing land-based wind energy sites. Radar will likely play an even more important role at the increasing development of wind energy offshore, given both the lack of knowledge about bird and bat activity offshore and the increased difficulty in obtaining offshore information. Most radar studies to date have used off-the-shelf or modified marine radars. However, there are several issues that continue to hinder the potential usefulness of radar at wind energy sites, with offshore sites providing a particular suite of challenges. We identify these challenges along with current or developing solutions.

  15. Analysis of Offshore Wind Energy Leasing Areas for the Rhode Island/Massachusetts Wind Energy Area

    Energy Technology Data Exchange (ETDEWEB)

    Musial, W.; Elliott, D.; Fields, J.; Parker, Z.; Scott, G.

    2013-04-01

    The National Renewable Energy Laboratory (NREL), under an interagency agreement with the Bureau of Ocean Energy Management (BOEM), is providing technical assistance to BOEM on the identification and delineation of offshore leasing areas for offshore wind energy development within the Atlantic Coast Wind Energy Areas (WEAs) established by BOEM in 2012. This report focuses on NREL's evaluation of BOEM's Rhode Island/Massachusetts (RIMA) WEA leasing areas. The objective of the NREL evaluation was to assess the proposed delineation of the two leasing areas and determine if the division is reasonable and technically sound. Additionally, the evaluation aimed to identify any deficiencies in the delineation. As part of the review, NREL performed the following tasks: 1. Performed a limited review of relevant literature and RIMA call nominations. 2. Executed a quantitative analysis and comparison of the two proposed leasing areas 3. Conducted interviews with University of Rhode Island (URI) staff involved with the URI Special Area Management Plan (SAMP) 4. Prepared this draft report summarizing the key findings.

  16. Optimal, reliability-based turbine placement in off-shore wind turbine parks

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard

    2007-01-01

    Offshore wind turbines for electricity production placed in wind farms are expected to be of one of the major future contributors for sustainable energy production. In this paper some of the problems associated with optimal planning and design of wind turbine parks are addressed. The number of wind...... turbines in a park is usually restricted to be placed within a fixed, limited geographical area. Behind a wind turbine a wake is formed where the mean wind speed decreases and the turbulence intensity increases. The distance between the turbines is among other things dependent on the recovery of wind...... energy behind the neighboring turbines and the increased wind load. Models for the mean wind speed and turbulence intensity in wind turbine parks are considered with emphasis on modeling the spatial correlation. Representative limit state equations for structural failure of wind turbine towers...

  17. Offshore vertical wind shear: Final report on NORSEWInD’s work task 3.1

    DEFF Research Database (Denmark)

    Pena Diaz, Alfredo; Mikkelsen, Torben; Gryning, Sven-Erik

    .6 Results input into satellite maps The nature of the offshore vertical wind shear is investigated using acquired data from the NORSEWInD network of mast and wind lidar stations. The importance of the knowledge of the vertical wind speed profile and wind shear is first illustrated for the evaluation...... of power outputs. Background related to the parametrization of the vertical wind speed profile and the behavior of the vertical wind shear in and beyond the atmospheric surface layer is presented together with the application of the long-term atmospheric stability parameters for the analysis of the long......-term vertical wind speed profile. Observed vertical wind shears are illustrated for all NORSEWInD wind lidar and meteorological stations in terms of wind shear roses, distributions, and diurnal and monthly evolutions. A multi-variational correlation analysis is performed to study the vertical wind shear...

  18. Reliability of Offshore Wind Turbine Drivetrains based on Measured Shut-down Events

    DEFF Research Database (Denmark)

    Natarajan, Anand; Buhl, Thomas

    2015-01-01

    The key objective of this paper is to investigate the frequency of normal shutdowns to be used in the design stage of wind turbines, based on measurements at an offshore wind farm and thereby quantify the irimpact on the fatigue loads on the drivetrain and tower top. The measured shut-downs...... observed on a fully instrumented multi megawatt wind turbine located in an offshore wind farm are correlated with corresponding observations of shutdowns on surrounding windturbines. The observed wind turbines have multiple shut-downs at high mean wind speeds. The normal shutdown is brought about....... A simulation model of the wind turbine is set up in the aeroelastic software HAWC2, based on which the observed shut-downs are simulated, along with normal operation. The simulated tower topmoments are compared with the measured loads, thereby quantifying the amplification in the loads due to the shutdown...

  19. Comparing offshore wind farm wake observed from satellite SAR and wake model results

    Science.gov (United States)

    Bay Hasager, Charlotte

    2014-05-01

    Offshore winds can be observed from satellite synthetic aperture radar (SAR). In the FP7 EERA DTOC project, the European Energy Research Alliance project on Design Tools for Offshore Wind Farm Clusters, there is focus on mid- to far-field wind farm wakes. The more wind farms are constructed nearby other wind farms, the more is the potential loss in annual energy production in all neighboring wind farms due to wind farm cluster effects. It is of course dependent upon the prevailing wind directions and wind speed levels, the distance between the wind farms, the wind turbine sizes and spacing. Some knowledge is available within wind farm arrays and in the near-field from various investigations. There are 58 offshore wind farms in the Northern European seas grid connected and in operation. Several of those are spaced near each other. There are several twin wind farms in operation including Nysted-1 and Rødsand-2 in the Baltic Sea, and Horns Rev 1 and Horns Rev 2, Egmond aan Zee and Prinses Amalia, and Thompton 1 and Thompton 2 all in the North Sea. There are ambitious plans of constructing numerous wind farms - great clusters of offshore wind farms. Current investigation of offshore wind farms includes mapping from high-resolution satellite SAR of several of the offshore wind farms in operation in the North Sea. Around 20 images with wind farm wake cases have been retrieved and processed. The data are from the Canadian RADARSAT-1/-2 satellites. These observe in microwave C-band and have been used for ocean surface wind retrieval during several years. The satellite wind maps are valid at 10 m above sea level. The wakes are identified in the raw images as darker areas downwind of the wind farms. In the SAR-based wind maps the wake deficit is found as areas of lower winds downwind of the wind farms compared to parallel undisturbed flow in the flow direction. The wind direction is clearly visible from lee effects and wind streaks in the images. The wind farm wake cases

  20. 75 FR 21653 - Commercial Leasing for Wind Power on the Outer Continental Shelf (OCS) Offshore Delaware-Request...

    Science.gov (United States)

    2010-04-26

    ... Leasing for Wind Power on the Outer Continental Shelf (OCS) Offshore Delaware--Request for Interest (RFI... proposal. In June 2008, Bluewater Wind Delaware LLC announced that it signed a 25-year power purchase agreement with Delmarva Power to sell up to 200 megawatts (MW) of power to the utility from an offshore wind...