SS: Offshore Wind Energy Special Session: Inspection Guidance for Offshore Wind Turbine Facilities

Author(s):  
Robert Edward Sheppard ◽  
Frank Puskar ◽  
Chris Waldhart
Author(s):  
Abdollah A. Afjeh ◽  
◽  
Brett Andersen ◽  
Jin Woo Lee ◽  
Mahdi Norouzi ◽  
...  

Development of novel offshore wind turbine designs and technologies are necessary to reduce the cost of offshore wind energy since offshore wind turbines need to withstand ice and waves in addition to wind, a markedly different environment from their onshore counterparts. This paper focuses on major design challenges of offshore wind turbines and offers an advanced concept wind turbine that can significantly reduce the cost of offshore wind energy as an alternative to the current popular designs. The design consists of a two-blade, downwind rotor configuration fitted to a fixed bottom or floating foundation. Preliminary results indicate that cost savings of nearly 25% are possible compared with the conventional upwind wind turbine designs.


Energies ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 6571
Author(s):  
Kwangtae Ha ◽  
Jun-Bae Kim ◽  
Youngjae Yu ◽  
Hyoung-Seock Seo

Not only the driving for offshore wind energy capacity of 12 GW by Korea’s Renewable Energy 2030 plan but also the need for the rejuvenation of existing world-class shipbuilders’ infrastructures is drawing much attention to offshore wind energy in Korea, especially to the diverse substructures. Considering the deep-sea environment in the East Sea, this paper presents detailed modeling and analysis of spar-type substructure for a 5 MW floating offshore wind turbine (FOWT). This process uses a fully coupled integrated load analysis, which was carried out using FAST, a widely used integrated load analysis software developed by NREL, coupled with an in-house hydrodynamic code (UOU code). The environmental design loads were calculated from data recorded over three years at the Ulsan Marine buoy point according to the ABS and DNVGL standards. The total 12 maximum cases from DLC 6.1 were selected to evaluate the structural integrity of the spar-type substructure under the three co-directional conditions (45°, 135°, and 315°) of wind and wave. A three-dimensional (3D) structural finite element (FE) model incorporating the wind turbine tower and floating structure bolted joint connection was constructed in FEGate (pre/post-structural analysis module based on MSC NASTRAN for ship and offshore structures). The FEM analysis applied the external loads such as the structural loads due to the inertial acceleration, buoyancy, and gravity, and the environmental loads due to the wind, wave, and current. The three-dimensional FE analysis results from the MSC Nastran software showed that the designed spar-type substructure had enough strength to endure the extreme limitation in the East Sea based on the von Mises criteria. The current process of this study would be applicable to the other substructures such as the submersible type.


Energies ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 5102
Author(s):  
Yu Hu ◽  
Jian Yang ◽  
Charalampos Baniotopoulos

Offshore wind energy is a rapidly maturing renewable energy technology that is poised to play an important role in future energy systems. The respective advances refer among others to the monopile foundation that is frequently used to support wind turbines in the marine environment. In the present research paper, the structural response of tall wind energy converters with various stiffening schemes is studied during the erection phase as the latter are manufactured in modules that are assembled in situ. Rings, vertical stiffeners, T-shaped stiffeners and orthogonal stiffeners are considered efficient stiffening schemes to strengthen the tower structures. The loading bearing capacity of offshore monopile wind turbine towers with the four types of stiffeners were modeled numerically by means of finite elements. Applying a nonlinear buckling analysis, the ultimate bearing capacity of wind turbine towers with four standard stiffening schemes were compared in order to obtain the optimum stiffening option.


2012 ◽  
Vol 446-449 ◽  
pp. 1014-1019 ◽  
Author(s):  
Ruo Yu Zhang ◽  
Chao He Chen ◽  
You Gang Tang ◽  
Xiao Yan Huang

The water area in which water depth is deeper than 50m has special advantage in wind turbine generation, because there are the stable wind speed and small Wind-shear. In such sea area, the offshore wind energy generating equipments should be set up on floating foundation structure. Therefore, it is of great significance to study the floating foundation structures that are available for offshore wind energy generation for the industrialization of the offshore wind power generation. In this paper, the basic type and working principles are reviewed for some novel floating structures developed in recent year. In addition, some key dynamical problems and risk factors of the floating structure are systemically analyzed for working load caused by turbine running and sea environment loads of floating structure. The results are valuable for designing the floating structures of wind turbine generation.


Author(s):  
Xujie Zhang ◽  
Ping Wu ◽  
Jiajun He ◽  
Yichao Liu ◽  
Lin Wang ◽  
...  

Currently, the offshore wind turbine has become a hot research area in the wind energy industry. Among different offshore wind turbines, floating offshore wind turbine (FOWT) can harvest abundant wind energy in deepwater areas. However, the harsh working environment will dramatically increase the maintenance cost and downtime of FOWTs. Wind turbine fault diagnosis is being regarded as an indispensable system for maintenance issues. Owing to the complexity of FOWT, it imposes an enormous challenge for effective fault diagnosis. This paper develops a novel FOWT fault diagnosis method based on a stacked denoising autoencoder (SDAE). First, a sliding window technique is adopted for time-series data to preserve temporal information. Then, SDAE is employed to extract the features from high-dimensional data. Based on the extracted features from SDAE, a classifier using multilayer perceptrons (MLP) is developed to determine the health status of the FOWT. To verify the performance of the proposed method, a FOWT simulation benchmark based on the National Renewable Energy Laboratory (NREL) FAST simulator is employed. Results show the superior performance of the proposed method by comparison with other relevant methods.


Author(s):  
Hideyuki Suzuki ◽  
Akira Sato

Due to the limited land area and mountainous topography, Japan is not necessarily suited for land-based wind power generation. But potential of offshore wind energy around the country is huge and has ability to supply whole electricity of the country. Development of offshore wind energy is also a promising solution for establishing sustainable society in the country. Water depth around the country generally becomes sharply deeper with distance from the shoreline and floating platform is necessary to deploy wind turbines. This paper investigates effect of motion of floating platform on the strength of turbine blade, a key issue in designing floating wind turbine, and design requirement for floating platform was discussed. Inertial load induced in the turbine blade by the motion of platform and rotation of turbine was formulated. The formulated load on the blade was verified by experiment with rotating rod on the oscillating tower. Two analysis codes, structural analysis code of turbine blade and motion analysis code of SPAR type floating platform, were developed. The effect of platform motion on the bending moment induced in the blade was investigated using the codes and design requirements for the platform were investigated from a viewpoint of maximum load and fatigue load. From a series of analysis on 5MW wind turbine showed that maximum load on blade is increased by 10% for pitching with amplitude of 5degrees but sectional modulus must be increased by 50% for fatigue. It is concluded that the increase of maximum load on the blade due to the motion of floating platform is not serious but fatigue load can be significant. Design requirement for the motion of floating platform will be that the amplitude of pitching motion should be less than a few degrees so that the land-based wind turbine can be installed on the floating platform with minimum modification.


2021 ◽  
Vol 9 (10) ◽  
pp. 1093
Author(s):  
Shan Gao ◽  
Lixian Zhang ◽  
Wei Shi ◽  
Bin Wang ◽  
Xin Li

Offshore wind energy, a clean energy resource, is considered to be a possible alternative to fossil energy. Floating offshore wind technology is considered to be a proper concept to develop abundant wind energy in deep water. Considering the reality of offshore wind energy development in China, the floating offshore wind turbine concept is expected to be developed at moderate water depths. In this paper, a mooring system of the WindFloat semisubmersible floating offshore wind turbine (SFOWT) at a water depth of 60 m is designed. The dynamic responses of the WindFloat SFOWT under different wind–wave combination conditions are investigated using the coupled method and the simplified method, which do not include the effect of the tower top motion in the aerodynamic calculation. The results show that the dynamic responses of the WindFloat SFOWT, including the platform motions, tower loads, and mooring line tensions, perform fairly well at a moderate water depth. A comparison between the coupled method and simplified method shows that the calculated results are slightly different between the different conditions for the time domain results, response spectra results, and fatigue results. In addition, mooring line 1 (ML 1) suffers higher fatigue damage than ML2, which should be paid more attention.


Author(s):  
Sukanta Roy ◽  
Hubert Branger ◽  
Christopher Luneau ◽  
Denis Bourras ◽  
Benoit Paillard

The rapid shrinkage of fossil fuel sources and contrary fast-growing energy needs of social, industrial and technological enhancements, necessitate the need of different approaches to exploit the various renewable energy sources. Among the several technological alternatives, wind energy is one of the most emerging prospective because of its renewable, sustainable and environment friendly nature, especially at its offshore locations. The recent growth of the offshore wind energy market has significantly increased the technological importance of the offshore vertical axis wind turbines, both as floating or fixed installations. Particularly, the class of lift-driven vertical axis wind turbines is very promising; however, the existing design and technology is not competent enough to meet the global need of offshore wind energy. In this context, the project AEROPITCH co-investigated by EOLFI, CORETI and IRPHE aims at the development of a robust and sophisticated offshore vertical axis wind turbine, which would bring decisive competitive advantage in the offshore wind energy market. In this paper, simulations have been performed on the various airfoils of NACA 4-series, 5-series and Selig profiles at different chord Reynolds numbers of 60000, 100000 and 140000 using double multiple streamtube model with tip loss correction. Based on the power coefficient, the best suitable airfoil S1046 has been selected for a 3-bladed vertical axis wind turbine. Besides the blade profile, the turbine design parameters such as aspect ratio and solidity ratio have also been investigated by varying the diameter and chord of the blade. Further, a series of wind tunnel experiments will be performed on the developed wind turbine, and the implementation of active pitch control in the developed turbine will be investigated in future research.


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