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Theoretical and Technical Challenges in Offshore Wind Power

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A special issue of Energies (ISSN 1996-1073). This special issue belongs to the section "A3: Wind, Wave and Tidal Energy".

Deadline for manuscript submissions: closed (10 August 2023) | Viewed by 10393

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Special Issue Editors

Prof. Dr. Xin Cai

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Guest Editor

College of Mechanics and Materials, Hohai University, Nanjing 211100, China
Interests: offshore wind power; modern design theory of engineering structure; high dam structure and complex foundation; modern model trials and tests; engineering mechanics; hydraulic structure engineering

Dr. Hao Wang

E-Mail Website
Guest Editor

College of Mechanics and Materials, Hohai University, Nanjing 211100, China
Interests: offshore wind power; wind engineering and industrial aerodynamics; wind energy utilization; engineering disaster prevention; ocean engineering

Dr. Bofeng Xu

E-Mail Website
Guest Editor

1. College of Energy and Electrical Engineering, Hohai University, Nanjing 211100, China
2. School of Engineering, Newcastle University, Newcastle upon Tyne NE1 7RU, UK
Interests: offshore wind power; aerodynamics of wind turbines; optimization design of wind turbine blades

Special Issue Information

Dear Colleagues,

Offshore wind energy is becoming a leader in the renewable energy sector. Furthermore, the target for achieving net-zero greenhouse gas emissions is a matter of urgency. However, expanding the development of offshore wind globally requires further innovation and lower energy costs. Economic pressure has driven the global offshore wind industry continuously towards using larger wind turbines that have larger, longer, and consequently more flexible towers and blades, as well as more complex floating platforms. This Special Issue will deal with theoretical and technical challenges in offshore wind power.

We invite scholars, industrial researchers, and government representatives around the world to submit papers for a Special Issue of Energies entitled “Theoretical and Technical Challenges in Offshore Wind Power”. Topics of interest include, but are not limited to:

Assessment of marine wind resources.
Structure safety of offshore wind turbine.
Flow field simulation of floating offshore wind turbines.
Hydrodynamic performance of floating platforms of offshore wind turbines.
Operation and maintenance strategies for offshore wind power.
Grid systems of offshore wind farms.
Tropical cyclone impact on offshore wind farms.
Environmental impact of offshore wind farms.

Prof. Dr. Xin Cai
Dr. Hao Wang
Dr. Bofeng Xu
Guest Editors

Manuscript Submission Information

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Keywords

marine wind resources
offshore wind turbine
offshore wind energy
offshore wind power
offshore wind farms
net-zero greenhouse gas emissions

Published Papers (7 papers)

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Research

19 pages, 8001 KiB

Open AccessArticle

Study on the Effect of Initial Delamination on Tensile Behavior of Offshore Wind Turbine Blade Spar Cap

by Wen Xin, Hui Li, Xiaolong Lu and Bo Zhou

Energies 2023, 16(8), 3607; https://doi.org/10.3390/en16083607 - 21 Apr 2023

Viewed by 1177

Abstract

Delamination damage to spar caps seriously endangers the operation safety of offshore wind turbines. The effect of initial delamination of various depths and areas on the ultimate tensile load of laminates is studied based on experiments and numerical simulation, and an effective method for predicting the residual tensile strength of laminates with high thickness is proposed. Three groups of initial delamination specimens with different characteristics were fabricated, and static displacement tensile tests were carried out. An accurate three-dimensional numerical analysis model was established, and the results were in good agreement with the experimental values, with the overall error of the failure load being less than 6%. Furthermore, a numerical model for a 20-ply high-thickness spar cap laminate was established to predict the effect of delamination on tensile strength. The results showed that, for the same depth of initial delamination, the difference in delamination area had little influence on the tensile strength. The dangerous locations of delamination were at the shallow surface and at the ratio of 0.3–0.4 in the thickness direction, and the maximum decrease in tensile strength was 14.86%; meanwhile, it was found that delamination on the middle surface had no significant effect on tensile strength. Full article

(This article belongs to the Special Issue Theoretical and Technical Challenges in Offshore Wind Power)

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13 pages, 4885 KiB

Open AccessArticle

Comparison of Blade Aeroelastic Responses between Upwind and Downwind of 10 MW Wind Turbines under the Shear Wind Condition

by Haojie Kang, Bofeng Xu, Xiang Shen, Zhen Li, Xin Cai and Zhiqiang Hu

Energies 2023, 16(6), 2567; https://doi.org/10.3390/en16062567 - 08 Mar 2023

Viewed by 1220

Abstract

This paper examines the potential for reducing the cost of energy for super-scale wind turbines through the use of a downwind configuration. Using nonlinear aeroelastic modeling, the responses of 10 MW upwind and downwind wind turbine blades are simulated and compared under shear wind conditions. The study evaluates the impact of both nonlinear and linear aeroelastic models on the dynamic response of different blade sizes, highlighting the need for a nonlinear approach. Results indicate that the linear model overestimates blade deformations (18.14%) and the nonlinear model is more accurate for predicting the aeroelastic response of ultra-long blades of 86.35 m. The study also finds that the downwind turbine blade experiences smaller flapwise moment (17.53%), and blade tip flapwise deformation (33.97%) than the upwind turbine blade, with increased load and deformation fluctuation as wind shear increases. Full article

(This article belongs to the Special Issue Theoretical and Technical Challenges in Offshore Wind Power)

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17 pages, 4366 KiB

Open AccessArticle

Research of Turbine Tower Optimization Based on Criterion Method

by Dan Li, Hongbing Bao and Ning Zhao

Energies 2023, 16(2), 906; https://doi.org/10.3390/en16020906 - 13 Jan 2023

Cited by 1 | Viewed by 1173

Abstract

Tower cost makes up an important part in the whole wind turbine construction especially for offshore wind farms. The main method to reduce tower cost is to reduce tower weight by optimum design. This paper proposes a two-level optimization criterion method for the optimal design of steel conical tower considering different structural reliability and uncertainty, along with the discreteness of design variables such as tower thickness and bolt type. In the first level, the tower shell geometry can be obtained by section design method; in the second level, bolted connections and flanges are designed based on the results of the first level. Then, summarized analysis and iterative calculation is performed to obtain optimum tower design with constant strength and rigidness. This method will play an important role in offshore customized turbine design. Full article

(This article belongs to the Special Issue Theoretical and Technical Challenges in Offshore Wind Power)

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24 pages, 22310 KiB

Open AccessArticle

Repair Parameter Design of Outer Reinforcement Layers of Offshore Wind Turbine Blade Spar Cap Based on Structural and Aerodynamic Analysis

by Hui Li, Xiaolong Lu, Wen Xin, Zhihui Guo, Bo Zhou, Baokuan Ning and Hongbing Bao

Energies 2023, 16(2), 712; https://doi.org/10.3390/en16020712 - 07 Jan 2023

Cited by 1 | Viewed by 1435

Abstract

The influence of the outer reinforcement layers on the repair structure and aerodynamic performance was studied. Firstly, a continuous damage mechanics model was established, and the 3D Hashin criterion and cohesive zone material model were used to analyze the damage repair model. The [...] Read more.

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transition model and SST–ω turbulence model, the aerodynamic analysis model of DU300 airfoil was established. The numerical simulation results showed that the lift coefficient and pressure distribution at the angle of attack of 10° and 15° were deviated from the experimental values by 2%. Furthermore, 27 structural repair models, nine 2D aerodynamic repair models, and a 3D full-scale blade model were designed. It was found that, when the repair length accounted for 60% of the total model length, the failure load increased by 22%, but the aerodynamic power with the repair length of 10 m was decreased by 0.137%. When the repair area was large and the repair height was from 4 mm to 6 mm, the failure load was greatly increased by about 30%, and the aerodynamic pressure distribution and static pressure field fluctuated significantly. The results show that the structural and aerodynamic characteristics were closely related to the repair parameters. Full article

(This article belongs to the Special Issue Theoretical and Technical Challenges in Offshore Wind Power)

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15 pages, 3182 KiB

Open AccessArticle

Joint Planning of Offshore Wind Power Storage and Transmission Considering Carbon Emission Reduction Benefits

by Honglin Chen, Hao Yu, Xiaojuan Yang, Yong Lin, Suhua Lou and Sui Peng

Energies 2022, 15(20), 7599; https://doi.org/10.3390/en15207599 - 14 Oct 2022

Cited by 4 | Viewed by 1251

Abstract

There are two situations of transmission redundancy and transmission congestion when large-scale offshore wind farms send power out. The energy storage system can store the power blocked by wind power due to insufficient transmission capacity and release it in the period when the wind power output level is low. In this paper, a full-life-cycle cost model is established for energy storage, and a joint planning model for offshore wind power storage and transmission considering carbon emission reduction benefits is established, which integrates power grid transmission benefits, carbon emission reduction benefits, energy storage construction costs, transmission project construction costs and wind abandonment penalty costs. The channel construction and energy storage configuration scheme with the greatest net benefit can be obtained. The relationship between the transmission channel capacity setting and the energy storage parameter configuration under this model is studied, and the combined effect of transmission channel and energy storage system in improving the level of wind power transmission is analyzed. The sensitivity analysis of the influence of the optimal storage and transmission planning scheme of the offshore wind farms is carried out from the perspectives of transmission line engineering cost and transmission channel curve type. Full article

(This article belongs to the Special Issue Theoretical and Technical Challenges in Offshore Wind Power)

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11 pages, 1534 KiB

Open AccessArticle

Performance Analysis of Ultra-Scale Downwind Wind Turbine Based on Rotor Cone Angle Control

by Zhen Li, Bofeng Xu, Xiang Shen, Hang Xiao, Zhiqiang Hu and Xin Cai

Energies 2022, 15(18), 6830; https://doi.org/10.3390/en15186830 - 18 Sep 2022

Viewed by 1777

Abstract

The theoretical feasibility of the power output strategy based on rotor cone angle control for ultra-scale downwind wind turbines is studied in this paper via the Open FAST simulation platform. The performance of five cases, namely UW, DW, DWC, DW6, and DW6IC, which have different rotor parameters or control strategies compared with the reference DTU 10 MW wind turbine, are calculated and analyzed. It is found that the downwind rotors have significant advantages in reducing the blade root load. The DW case reduces the peak load at the blade root by 22.54% at the cost of 1.57% annual energy production loss. By extending the length and redesigning the stiffness of the blade, the DW6 case achieves 14.82% reduction in the peak load at the blade root and 1.67% increase in the annual energy production under the same blade weight as that of the UW. The DWC case with rotor cone angle control has the same aerodynamic performance as the DW case with the same blade parameters. However, when the wind speed achieves or exceeds the rated speed, the blade root load decreases at a greater rate with the increasing wind speeds, and achieves minimum load with a wind speed of 16 m/s. Compared with the UW case, the DW6IC case with the improved rotor cone angle control reduces the peak load of the blade root by 22.54%, leading to an increase in annual energy production by 1.12% accordingly. Full article

(This article belongs to the Special Issue Theoretical and Technical Challenges in Offshore Wind Power)

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11 pages, 3714 KiB

Open AccessArticle

Study of Tower Clearance Safety Protection during Extreme Gust Based on Wind Turbine Monitoring Data

by Yazhou Wang, Xin Cai, Shifa Lin, Bofeng Xu, Yuan Zhang and Saixian Bian

Energies 2022, 15(12), 4400; https://doi.org/10.3390/en15124400 - 16 Jun 2022

Cited by 2 | Viewed by 1231

Abstract

Large-scale wind turbines often face the problem of tower clearance safety under extreme gust conditions. Since gust intensity is positively correlated with the change rate of the generator’s speed, a gust identification method is proposed based on wind turbine monitoring data. Furthermore, a novel tower clearance safety protection strategy is proposed, which superimposes some additional speed requirements on the basis of normal pitch rate when identifying extreme gust so as to alleviate the dynamic response of the wind turbine. Simulations and comparison of a 5 MW wind turbine, before and after applying the new strategy, showed that the new strategy can induce an increase in pitch angle for the wind turbine and, simultaneously, avoids the emergency stop caused by the generator’s overspeed. Meanwhile, when the new strategy is adopted, the blade tip’s deformation and the load on the top of the tower are reduced by 19.9% and 52.2%, respectively. Therefore, the proposed strategy can not only protect the safety of the wind turbine but it also reduces costs. Full article

(This article belongs to the Special Issue Theoretical and Technical Challenges in Offshore Wind Power)

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