scholarly journals Scour Protections for Offshore Foundations of Marine Energy Harvesting Technologies: A Review

2021 ◽  
Vol 9 (3) ◽  
pp. 297
Author(s):  
Tiago Fazeres-Ferradosa ◽  
João Chambel ◽  
Francisco Taveira-Pinto ◽  
Paulo Rosa-Santos ◽  
Francisco V. C. Taveira Pinto ◽  
...  
Keyword(s):  
Renewable Energy ◽  
Wind Turbine ◽  
Marine Environment ◽  
Professional Community ◽  
Tidal Energy ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Limit States ◽  
Commercial Development ◽  
Marine Renewable Energy

The offshore wind is the sector of marine renewable energy with the highest commercial development at present. The margin to optimise offshore wind foundations is considerable, thus attracting both the scientific and the industrial community. Due to the complexity of the marine environment, the foundation of an offshore wind turbine represents a considerable portion of the overall investment. An important part of the foundation’s costs relates to the scour protections, which prevent scour effects that can lead the structure to reach the ultimate and service limit states. Presently, the advances in scour protections design and its optimisation for marine environments face many challenges, and the latest findings are often bounded by stakeholder’s strict confidential policies. Therefore, this paper provides a broad overview of the latest improvements acquired on this topic, which would otherwise be difficult to obtain by the scientific and general professional community. In addition, this paper summarises the key challenges and recent advances related to offshore wind turbine scour protections. Knowledge gaps, recent findings and prospective research goals are critically analysed, including the study of potential synergies with other marine renewable energy technologies, as wave and tidal energy. This research shows that scour protections are a field of study quite challenging and still with numerous questions to be answered. Thus, optimisation of scour protections in the marine environment represents a meaningful opportunity to further increase the competitiveness of marine renewable energies.

Individual Blade Pitch Control for Alleviation of Vibratory Loads on Floating Offshore Wind Turbines

2021 ◽  
Author(s):  
Luca Pustina ◽  
Claudio Pasquali ◽  
Jacopo Serafini ◽  
Claudio Lugni ◽  
Massimo Gennaretti
Keyword(s):  
Renewable Energy ◽  
Wind Turbine ◽  
Bending Moment ◽  
Offshore Wind ◽  
Synthesis Process ◽  
Control Synthesis ◽  
Offshore Wind Turbine ◽  
Floating Offshore Wind Turbine ◽  
Blade Root ◽  
Floating Offshore Wind Turbines

Abstract Among the renewable energy technologies, offshore wind energy is expected to provide a significant contribution for the achievement of the European Renewable Energy (RE) targets for the next future. In this framework, the increase of generated power combined with the alleviation of vibratory loads achieved by application of suitable advanced control systems can lead to a beneficial LCOE (Levelized Cost Of Energy) reduction. This paper defines a control strategy for increasing floating offshore wind turbine lifetime through the reduction of vibratory blade and hub loads. To this purpose a Proportional-Integral (PI) controller based on measured blade-root bending moment feedback provides the blade cyclic pitch to be actuated. The proportional and integral gain matrices are determined by an optimization procedure whose objective is the alleviation of the vibratory loads due to a wind distributed linearly on the rotor disc. This control synthesis process relies on a linear, state-space, reduced-order model of the floating offshore wind turbine derived from aero-hydroelastic simulations provided by the open-source tool OpenFAST. In addition to the validation of the proposed controller, the numerical investigation based on OpenFAST predictions examines also the corresponding control effort, influence on platform dynamics and expected blade lifetime extension. The outcomes show that, as a by-product of the alleviation of the vibratory out-of-plane bending moment at the blade root, significant reductions of both cumulative blade lifetime damage and sway and roll platform motion are achieved, as well. The maximum required control power is less than 1% of the generated power.

scholarly journals Analysis of Offshore Wind Turbine Towers with Different Designs by Finite Elements Method

2018 ◽  
Vol 4 (3) ◽  
pp. 1 ◽  
Author(s):  
Ensari Yigit M ◽  
Anil Ozdemir ◽  
Fethi Sermet ◽  
Murat Pinarlik
Keyword(s):  
Renewable Energy ◽  
Reinforced Concrete ◽  
Finite Elements ◽  
Wind Turbine ◽  
Turbine Blades ◽  
Finite Elements Method ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Wind Turbine Towers ◽  
Materials Used

It is known that the use of renewable energy has an increasing trend in whole world. Wind energy is one of the renewable energy types, as well is among the cleanest and most economical energy sources. Nowadays, in order to provide much more energy from wind, turbine towers are being built higher and the turbine blades have begun to be manufactured longer. Due to these applications, tower and turbine weights are continuously increasing. For this reason, it is necessary to optimize the materials used as well as the dimensions of the turbine towers. In the present study, behavior of TLP floating wind turbine towers with three different designs under wave, hydrostatic and static loads were investigated. In order to clarify the effect of these loads, turbine designs were analyzed in the ratio of 1/5 using finite elements method. Steel, reinforced concrete and hybrid (reinforced concrete and steel) wind turbine towers tied to sea floor at a depth of 10 meters rigidly by TLP floating method. In this context, 10-meter-high turbine towers having three different designs which static analyzed previously were used for investigate effects of wave and hydrostatic loads. Turbine structures analyzed with ABAQUS finite elements model. The deformations and stress values of underwater turbine structures were obtained and compared with each other. As it can be seen from analysis results, compared to the reinforced concrete design, the displacement of steel tower design decreased 77.84%. It is seen that the torsion effect was dominant in the steel tower design. However, the decreasing displacement value for steel design was recorded as 44.43% compared to the hybrid tower design.

scholarly journals Multi-Disciplinary and Multi-Scale Assessment of Marine Renewable Energy Structure in a Tidal System

2021 ◽  
Vol 3 (1) ◽  
Author(s):  
Aurore Raoux ◽  
◽  
Ilan Robin ◽  
Jean-Philippe Pezy ◽  
Anne-Claire Bennis ◽  
...  
Keyword(s):  
Renewable Energy ◽  
Wind Farm ◽  
Scale Effects ◽  
Structural Characteristics ◽  
Tidal Energy ◽  
Ecosystem Approach ◽  
Offshore Wind ◽  
Future Research ◽  
Energy Structure ◽  
Marine Renewable Energy

The French coast of the Atlantic and English Channel (EC) is promising for the development of Marine Renewable Energy (MRE), including wind, wave, and tidal stream, due to the high velocity of currents in some parts of the area. This paper, focusing on wind and tidal energy, discusses how the implementation of MRE converters influences biodiversity, and vice versa, through biofouling and reef effects. The understanding of these interactions requires the knowledge of the hydro-sedimentary conditions and the macrofauna. The research on these topics, performed at the Continental and Coastal Morphodynamic laboratory (M2C) (UNICAEN, France), is presented through a multi-disciplinary approach by i) studying the hydrodynamic conditions and the macrofauna in Alderney Race, ii) studying the biofouling effects on tidal turbines and their influence on the turbulent wake, iii) assessing the hydro-sedimentary impacts induced by the offshore wind farm, like scouring, and iv) taking an ecosystem approach on MRE, such as the reef effect. From an ecological perspective, the reef effect can be responsible for changes in the structure and function of the ecosystem. Although several studies have analyzed this effect at the species-or community-scale, the propagation of the reef effect at the ecosystem-scale remains unclear. Thus, understanding these ecosystem-scale effects is urgent for future research. From an engineering perspective, biofouling changes the structural characteristics (i.e., supplementary mass) of the converters and thus, affects their performance.

The Marine Environment Impacts on the Supporting Structure of the Offshore Wind Turbines and Discussions on the Protective Measures

2014 ◽  
Vol 1065-1069 ◽  
pp. 1381-1389
Author(s):  
Yong Xiang Wu ◽  
Hong You Li ◽  
Hong Ming Chi ◽  
Li Yuan Liu ◽  
An Min Cai ◽  
...  
Keyword(s):  
Wind Turbine ◽  
Marine Environment ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Protective Measures ◽  
Offshore Wind Turbines ◽  
Supporting Structure ◽  
Seawater Corrosion ◽  
Negative Factors

Offshore wind turbine supporting structure long term works in the harsh marine environment, suffering from a variety of negative factors such as the seawater corrosion, marine growths, water scour, collision of sea ice and ship, etc.. Through numerical analysis software SACS and ANSYS, the marine environment impacts on the supporting structure and protective measures were put forward. The study found that such adverse environmental factors might easily result in a whole or partial component damage of the foundation support structure, and eventually lead to the reduction of security and durability. Reasonable preventive measures to ensure the security of the offshore wind turbine supporting structure were proposed and theoretical guidance for the design of future offshore foundation was provided.

scholarly journals Research of lightning transient potential on the jacket foundation offshore wind turbines

2019 ◽  
Vol 95 ◽  
pp. 02006 ◽  
Author(s):  
Shiqi Tao ◽  
Ximei Yao ◽  
Bojing Liu ◽  
Xiaoqing Zhang ◽  
Yaowu Wang
Keyword(s):  
Wind Turbine ◽  
Marine Environment ◽  
Wind Turbines ◽  
Efficient Algorithm ◽  
Circuit Model ◽  
Offshore Wind ◽  
Lightning Strike ◽  
Offshore Wind Turbine ◽  
Offshore Wind Turbines ◽  
Tall Structures

Offshore wind turbines are often struck by lightning due to their tall structures and the harsh marine environment. The high transient potential from lightning strike can cause serious damage for the devices of offshore turbines. For analysing the effect of transient potential, a complete transient circuit model is established and an efficient algorithm is also presented to evaluate the circuit parameters of blade, tower, and jacket foundation. On the basis of the circuit model, the transient potential at the different locations of the offshore wind turbine can be carried out during direct lightning strike by PSCAD. Finally, the circuit model is used by a numerical example of an actual Chinese-built offshore wind turbine.

An Assessment of Structural Design Guidelines for Offshore Wind Turbines

2007 ◽  
Author(s):  
Rakesh K. Saigal ◽  
Dan Dolan ◽  
Armen Der Kiureghian ◽  
Tim Camp ◽  
Charles E. Smith
Keyword(s):  
Renewable Energy ◽  
Wind Turbine ◽  
Wind Farms ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Guidance Document ◽  
Support Structures ◽  
Design Standards ◽  
Offshore Wind Farms ◽  
Design Requirements

This paper addresses the need for U.S. standards to establish design requirements for offshore wind turbine support structures. There are wind power resources in U.S. waters that can be developed to generate substantial amounts of clean, renewable energy. While a number of offshore wind farms have been proposed for U.S. waters none have been built. The U.S. Minerals Management Service and the National Renewable Energy Laboratory have recently commissioned a study to compare and benchmark the International Electrotechnical Commission (IEC) design standards with the American Petroleum Institute (API) recommended practices. Offshore wind farms that are operating in Europe have been designed using standards developed specifically for offshore wind, such as those developed by Germanischer Lloyd (GL) and Det Norske Veritas (DNV). The IEC has recently drafted design requirements specifically for offshore wind farms that provides a comprehensive definition of load conditions and references other standards, where needed, to provide a complete guidance document. The intent of this paper is to examine the range of applicability of the various design standards and to assess how these standards apply to the design of U.S. offshore wind turbine (OWT) support structures.

Development of a 10-MW Semisubmersible Type Floating Offshore Wind Turbine for the East Sea, Korea

2020 ◽  
Author(s):  
Hyeonjeong Ahn ◽  
Hyunkyoung Shin
Keyword(s):  
Renewable Energy ◽  
Wind Turbine ◽  
Wind Turbines ◽  
Wind Farm ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Mooring Lines ◽  
Floating Offshore Wind Turbines ◽  
Scale Ratio ◽  
The Stability

Abstract The area of renewable energy is expanding rapidly worldwide, with wind turbines being an example. In Korea, many researchers are conducting studies on floating offshore wind turbines (FOWTs) on areas with suitable wind resources. In particular, Ulsan, which is the site selected in this study, started research on the development of a 200-MW floating offshore wind farm. In this study, the references for upscaling are the 5-MW reference wind turbine of the National Renewable Energy Laboratory (NREL), and the OC4-DeepCwind semisubmersible type floating wind turbine. We upscaled the 5-MW wind turbine to a 10-MW FOWT by applying the appropriate scale ratio for each component of the turbine. We upscaled the specifications related to items such as the blades, hub, and nacelle using the power ratio. The mass of the blades was reduced by using carbon fiber-reinforced plastic (CFRP). We upscaled the specifications related to the tower using its deflection ratio, and the tower clearance criterion and the tower campbell diagram were used to confirm that the design is appropriate. We upscaled the specifications related to the platform using the upper structure mass ratio. The GZ curve of the platform was used to confirm the stability, and we used the air gap for safety. Three catenary type mooring lines were also designed. To understand the static response of the initial model of the 10-MW FOWT, a steady-state analysis was performed according to each wind speed. We followed the IEC and DNV standards, and we used NREL FAST in all simulations.

The effect of the marine environment on the stator insulation system of an offshore wind turbine generator

2015 ◽  
Vol 31 (3) ◽  
pp. 10-17 ◽  
Author(s):  
Xuezhong Liu ◽  
Tianlong Zhang ◽  
Rui Zhang ◽  
Yonggang Bai ◽  
Xiaoxia Ding ◽  
...  
Keyword(s):  
Wind Turbine ◽  
Marine Environment ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Insulation System ◽  
Turbine Generator ◽  
Wind Turbine Generator
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