scholarly journals The Relation between Migratory Activity of Pipistrellus Bats at Sea and Weather Conditions Offers Possibilities to Reduce Offshore Wind Farm Effects

Animals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 3457
Author(s):  
Robin Brabant ◽  
Yves Laurent ◽  
Bob Jonge Poerink ◽  
Steven Degraer

Bats undertaking seasonal migration between summer roosts and wintering areas can cross large areas of open sea. Given the known impact of onshore wind turbines on bats, concerns were raised on whether offshore wind farms pose risks to bats. Better comprehension of the phenology and weather conditions of offshore bat migration are considered as research priorities for bat conservation and provide a scientific basis for mitigating the impact of offshore wind turbines on bats. This study investigated the weather conditions linked to the migratory activity of Pipistrellus bats at multiple near- and offshore locations in the Belgian part of the North Sea. We found a positive relationship between migratory activity and ambient temperature and atmospheric pressure and a negative relationship with wind speed. The activity was highest with a wind direction between NE and SE, which may favor offshore migration towards the UK. Further, we found a clear negative relationship between the number of detections and the distance from the coast. At the nearshore survey location, the number of detections was up to 24 times higher compared to the offshore locations. Our results can support mitigation strategies to reduce offshore wind farm effects on bats and offer guidance in the siting process of new offshore wind farms.

2019 ◽  
Vol 107 ◽  
pp. 01004
Author(s):  
Haiyan Tang ◽  
Guanglei Li ◽  
Linan Qu ◽  
Yan Li

A large offshore wind farm usually consists of dozens or even hundreds of wind turbines. Due to the limitation of the simulation scale, it is necessary to develop an equivalent model of offshore wind farms for power system studies. At present, the aggregation method is widely adopted for wind farm equivalent modeling. In this paper, the topology, electrical parameters, operating conditions and individual turbine characteristics of the offshore wind farms are taken into consideration. Firstly, the output power distribution of offshore wind farm, the voltage distribution of the collector system and the fault ride-through characteristics of wind turbines are analyzed. Then, a dynamic equivalent modeling method for offshore wind farms is developed based on the fault characteristics analysis. Finally, the proposed method is validated through time-domain simulation.


2017 ◽  
Vol 2 (2) ◽  
pp. 477-490 ◽  
Author(s):  
Niko Mittelmeier ◽  
Julian Allin ◽  
Tomas Blodau ◽  
Davide Trabucchi ◽  
Gerald Steinfeld ◽  
...  

Abstract. For offshore wind farms, wake effects are among the largest sources of losses in energy production. At the same time, wake modelling is still associated with very high uncertainties. Therefore current research focusses on improving wake model predictions. It is known that atmospheric conditions, especially atmospheric stability, crucially influence the magnitude of those wake effects. The classification of atmospheric stability is usually based on measurements from met masts, buoys or lidar (light detection and ranging). In offshore conditions these measurements are expensive and scarce. However, every wind farm permanently produces SCADA (supervisory control and data acquisition) measurements. The objective of this study is to establish a classification for the magnitude of wake effects based on SCADA data. This delivers a basis to fit engineering wake models better to the ambient conditions in an offshore wind farm. The method is established with data from two offshore wind farms which each have a met mast nearby. A correlation is established between the stability classification from the met mast and signals within the SCADA data from the wind farm. The significance of these new signals on power production is demonstrated with data from two wind farms with met mast and long-range lidar measurements. Additionally, the method is validated with data from another wind farm without a met mast. The proposed signal consists of a good correlation between the standard deviation of active power divided by the average power of wind turbines in free flow with the ambient turbulence intensity (TI) when the wind turbines were operating in partial load. It allows us to distinguish between conditions with different magnitudes of wake effects. The proposed signal is very sensitive to increased turbulence induced by neighbouring turbines and wind farms, even at a distance of more than 38 rotor diameters.


Author(s):  
Philip H. Augener ◽  
Hannes Hatecke

Offshore wind farms are not planned in sheltered and shallow waters any longer. Especially in the North Sea there exist many approved offshore wind farm projects at water depth between 30 and 50 meters. In particular the installation process of these projects is strongly influenced by weather conditions and the sea-keeping capabilities of the installation vessels. For reliable planning of the entire project, not only the weather statistics, but also the vessel’s sea-keeping capabilities need to be known accurately. For this purpose different kinds of sea-keeping analyses can be conducted. In this paper a sea-keeping analysis is presented, where the focus is upon the jack-up process. For the numerical computation the sea-keeping code E4ROLLS is applied. The results of this sea-keeping analysis are operational limitations for the jack-up process, caused by two different criteria derived from jack-up classification requirements.


2019 ◽  
Vol 2019 ◽  
pp. 1-7 ◽  
Author(s):  
Binbin Zhang ◽  
Jun Liu

This paper proposed the SVD (singular value decomposition) clustering algorithm to cluster wind turbines into some group for a large offshore wind farm, in order to reduce the high-dimensional problem in wind farm power control and numerical simulation. Firstly, wind farm wake relationship matrixes are established considering the wake effect in an offshore wind farm, and the SVD of wake relationship matrixes is used to cluster wind turbines into some groups by the fuzzy clustering algorithm. At last, the Horns Rev offshore wind farm is analyzed to test the clustering algorithm, and the clustering result and the power simulation show the effectiveness and feasibility of the proposed clustering strategy.


2014 ◽  
pp. 179-183
Author(s):  
Matthew Shanley

There is a rapid increase in the number of offshore wind farms in European waters to help meet renewable energy targets. Wind turbines are being installed in progressively more exposed areas of the North Sea and the Irish Sea, with the eventual aim of placing them in the Atlantic Ocean. As offshore wind farms require regular maintenance, being able to access the wind turbines during rough sea conditions is a key issue for profitable operation. The operation involves transferring personnel from the service ship to the wind turbine. The current wave height limit for this is 1.5 m, slightly less than 5 feet, increasing this results in significant savings over the lifetime of the wind farm. Each wind farm service ship has 12 maintenance crew. Imagine you are one waiting on port for the sea and weather conditions to be right so that you can head out to the wind ...


2015 ◽  
Author(s):  
Blanca Peña ◽  
Erik P. ter Brake ◽  
Kyriakos Moschonas

A number of UK Round Three offshore wind farms are located relatively far from the coast making crew transfer to the sites time consuming, more prone to interruption by weather conditions and increasingly costly. In order to optimize the functionality of a permanent accommodation vessel, Houlder has developed a dedicated Accommodation and Maintenance Wind Farm vessel based on an oil & gas work-over vessel that has been successfully deployed for many years. The Accommodation and Maintenance (A&M) Wind Farm vessel is designed to provide an infield base for Marine Wind Farm operation. The A&M vessel is designed for high operability when it comes to crew access and performance of maintenance and repair of wind turbine components in its workshops. Also general comfort on board is of high regard. As such, the seakeeping behavior of the unit is of great importance. In this publication, the seakeeping behavior is presented on the basis of numerical simulations using 3D diffraction software. The first design iteration is driven by achieving high maneuverability and good motion characteristics for operational up-time and personnel comfort on board the vessel. Model test data of the original work-over vessel has been used to validate and calibrate the numerical simulations. On this basis, parametric studies can be performed to fine-tune a potential new hull form. In turn, this could reduce the number of required physical model tests providing a potential financial benefit and optimized delivery schedule. The vessel motion behavior was tested against the acceptability criteria and crew comfort guidelines of motion behavior for a North Sea environment.


Author(s):  
Caitlin Forinash ◽  
Bryony DuPont

An Extended Pattern Search (EPS) approach is developed for offshore floating wind farm layout optimization while considering challenges such as high cost and harsh ocean environments. This multi-level optimization method minimizes the costs of installation and operations and maintenance, and maximizes power development in a unidirectional wind case by selecting the size and position of turbines. The EPS combines a deterministic pattern search algorithm with three stochastic extensions to avoid local optima. The EPS has been successfully applied to onshore wind farm optimization and enables the inclusion of advanced modeling as new technologies for floating offshore wind farms emerge. Three advanced models are incorporated into this work: (1) a cost model developed specifically for this work, (2) a power development model that selects hub height and rotor radius to optimize power production, and (3) a wake propagation and interaction model that determines aerodynamic effects. Preliminary results indicate the differences between proposed optimal offshore wind farm layouts and those developed by similar methods for onshore wind farms. The objective of this work is to maximize profit; given similar parameters, offshore wind farms are suggested to have approximately 24% more turbines than onshore farms of the same area. EPS layouts are also compared to those of an Adapted GA; 100% efficiency is found for layouts containing twice as many turbines as the layout presented by the Adapted GA. Best practices are derived that can be employed by offshore wind farm developers to improve the layout of platforms, and may contribute to reducing barriers to implementation, enabling developers and policy makers to have a clearer understanding of the resulting cost and power production of computationally optimized farms; however, the unidirectional wind case used in this work limits the representation of optimized layouts at real wind sites. Since there are currently no multi-turbine floating offshore wind farm projects operational in the United States, it is anticipated that this work will be used by developers when planning array layouts for future offshore floating wind farms.


2021 ◽  
Author(s):  
Miteshkumar Nandlal Popat

Recently, offshore wind farms have emerged as the most promising sector in the global renewable energy industry. The main reasons for the rapid development of offshore wind farms includes much better wind resources and smaller environmental impact (e.g., audible noise and visual effect). However, the current state of the offshore wind power presents economic challenges significantly greater than onshore. In this thesis, a novel interconnecting method for permanent magnet synchronous generator (PMSG)-based offshore wind farm is proposed, where cascaded pulse-width modulated (PWM) current-source converters (CSCs) are employed on both generator- and grid-side. With the converters in cascade to achieve high operating voltages, the proposed method eliminates the need for bulky and very costly offshore converter substation which is usually employed in voltage source converter (VSC) high voltage DC (HVDC)-based counterparts. Related research in terms of control schemes and grid integration are carried out to adapt the proposed cascaded CSC-based offshore wind farm configuration. The large distance between generator- and grid-side CSC in the proposed wind farm configuration addresses significant challenges for the system control. In order to overcome the problem, a novel decoupled control scheme is developed. The active and reactive power control on the grid-side converters are achieved without any exchange of information from the generator-side controller. Therefore, the long distance communication links between the generator- and grid-side converters are eliminated and both controllers are completely decoupled. At the same time, the maximum power tracking control is achieved for the generator-side converters that enable full utilization of the wind energy. Considering inconsistent wind speed at each turbine, a coordinated control scheme is proposed for the cascaded CSC-based offshore wind farm. In proposed control strategy, the wind farm supervisory control (WFSC) is developed to generate the optimized dc-link current control. This enables all the turbines to independently track their own MPPT even with inconsistent wind speed at each turbine. Grid integration issues, especially the fault ride-through (FRT) capability for the cascaded CSC-based offshore wind farm are addressed. Challenges in implementing existing FRT methods to the proposed offshore wind farm are identified. Based on this, a new FRT strategy using inherent short circuit operating capability of the CSC is developed. Moreover, the mitigation strategy is developed to ensure the continuous operation of the cascaded CSC-based offshore wind farm when one or more turbines fail to operate. Simulation and experimental verification for various objectives are provided throughout the thesis. The results validate the proposed solutions for the main challenges of the cascaded current source converter based offshore wind farm.


2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Peilin Lv ◽  
Rong Zhen ◽  
Zheping Shao

Offshore wind power is an effective way to solve the energy crisis problem and achieve sustainable economic development. Aiming at the problems that the navigational risk of ships in the waters of offshore wind farms is difficult to quantify due to complex factors, this paper proposes a method of navigational risk assessment in the waters of offshore wind farms based on a fuzzy inference system. Firstly, through the analysis of the factors affecting the navigation system of wind farm waters, it is found that the navigational risk is affected by natural factors and navigational environment factors. Then, the visibility, the number of traffic flows, the number of encounter areas, and the distance between the sailing route and the wind farm are extracted to evaluate the risk of natural factors and the risk of the sailing environment in the navigation system of the wind farm waters, respectively. Considering the mutual influence of the factors, the fuzzy inference rules of navigational risk influence are established according to the expert experience, and a method of navigational risk assessment based on the fuzzy inference system in offshore wind farm waters is developed. In order to verify the effectiveness of the proposed method, a comprehensive evaluation of the navigational risk of wind farm waters in Changle offshore sea of Fujian Province is carried out, and the evaluation results are consistent with the actual situation. The proposed method has important theoretical significance for the navigational safety supervision of offshore wind farm waters.


Author(s):  
Ekkehard Stade

Offshore wind farms present a lesser safety risk to operators and contractors than traditional oil and gas installations. In the post Macondo world this does not come as a surprise since the risks involved in construction, operation and maintenance of an offshore wind farm are by far lower. Even with higher probability of incidents and near misses (due to serial construction) the severity/ impact of those is considerably lower. On the other hand projects are complex, profit margins are what they are called: marginal. Hence there is no room for errors, perhaps in form of delays. If, for example, the installation completion of the turbines and the inner array cabling/ export cables are not perfectly in tune, the little commercial success that can be achieved is rapidly diminishing by costly compensation activities. The paper will try to present solutions to the most pressing challenges and elaborate on the effect those would have had, had they been implemented at the beginning of the projects. How can a sustainable new industry evolve by learning from established industries? Presently, there is a view that offshore wind is a short-lived business. Particularly representatives of the oil and gas industry raise such concern. Apart from the obvious bias of those voices, this controversy is also caused by the fact that offshore wind seems to have a tendency to try and re-invent the wheel rather than using established procedures. Even with a relatively stable commitment to the offshore wind development regardless of the respective government focus within European coastal states the industry suffers from financing issues, subsidies, over-regulation due to lack of expertise within authorities and other challenges. The avoidance of those is key to a successful development for this industry in other areas of the planet. In conjunction with a stable commitment this is essential in order to attract the long lead-time projects and to establish the complex supply chains to achieve above goals. The paper will look at the short but intensive history of the industry and establish mitigation to some of the involved risks of offshore wind farm EPCI.


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