Energies

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25 pages, 34215 KiB

Open AccessArticle

A Novel Tripod Concept for Onshore Wind Turbine Towers

by Charis J. Gantes, Maria Villi Billi, Mahmut Güldogan and Semih Gül

Energies 2021, 14(18), 5772; https://doi.org/10.3390/en14185772 - 13 Sep 2021

Cited by 2 | Viewed by 3535

A wind turbine tower assembly is presented, consisting of a lower “tripod section” and an upper tubular steel section, aiming at enabling very tall hub heights for optimum exploitation of the wind potential. The foundation consists of sets of piles connected at their [...] Read more.

A wind turbine tower assembly is presented, consisting of a lower “tripod section” and an upper tubular steel section, aiming at enabling very tall hub heights for optimum exploitation of the wind potential. The foundation consists of sets of piles connected at their top by a common pile cap below each tripod leg. The concept can be applied for the realization of new or the upgrade of existing wind turbine towers. It is adjustable to both onshore and offshore towers, but emphasis is directed towards overcoming the stricter onshore transportability constraints. For that purpose, pre-welded individual tripod parts are transported and are then bolted together during erection, contrary to fully pre-welded tripods that have been used in offshore towers. Alternative constructional details of the tripod joints are therefore proposed that address the fabrication, transportability, on-site erection and maintenance requirements and can meet structural performance criteria. The main structural features are demonstrated by means of a typical case study comprising a 180-m-tall tower, consisting of a 120-m-tall tubular superstructure on top of a 60-m-tall tripod substructure. Realistic cross-sections are calculated, leading to weight and cost estimations, thus demonstrating the feasibility and competitiveness of the concept. Full article

(This article belongs to the Special Issue Advances in Wind Energy Structures)

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17 pages, 2102 KiB

Open AccessArticle

Economic Emission Dispatch for Wind Power Integrated System with Carbon Trading Mechanism

by Jingliang Jin, Qinglan Wen, Xianyue Zhang, Siqi Cheng and Xiaojun Guo

Energies 2021, 14(7), 1870; https://doi.org/10.3390/en14071870 - 28 Mar 2021

Cited by 14 | Viewed by 2249

Abstract

Nowadays, the power system is faced with some new changes from low-carbon approaches, though these approaches have proved to be effective in developing low-carbon electricity. Specifically, wind power integration and carbon trading influence the traditional economic emission dispatch (EED) mode, allowing for the [...] Read more.

Nowadays, the power system is faced with some new changes from low-carbon approaches, though these approaches have proved to be effective in developing low-carbon electricity. Specifically, wind power integration and carbon trading influence the traditional economic emission dispatch (EED) mode, allowing for the disturbance of wind power uncertainties and the fluctuation of carbon trading price. Aiming at the above problems, this study firstly builds a stochastic EED model in the form of chance-constrained programming associated with wind power reliability. Next, wind power features are deduced from the statistic characteristics of wind speed, and thus the established model is converted to a deterministic form. After that, an auxiliary decision-making method based on the technique for order preference by similarity to an ideal solution (TOPSIS) is designed to draw the optimal solution based upon the specific requirements of carbon emission control. The simulation results eventually indicate that the minimization of fuel costs and carbon emissions comes at the expense of wind power reliability. Meanwhile, carbon emission reduction can be effectively realized by carbon trading rather than a substantial increase in fuel costs, and carbon trading may help to improve power generation efficiency. Furthermore, carbon trading prices could be determined by the demands of carbon emission reduction and power generation efficiency improvement. Full article

(This article belongs to the Special Issue Advances in Wind Energy Structures)

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21 pages, 8321 KiB

Open AccessArticle

Lattice and Tubular Steel Wind Turbine Towers. Comparative Structural Investigation

by Nafsika Stavridou, Efthymios Koltsakis and Charalampos C. Baniotopoulos

Energies 2020, 13(23), 6325; https://doi.org/10.3390/en13236325 - 8 Dec 2020

Cited by 6 | Viewed by 5995

Abstract

Renewable energy is expected to experience epic growth in the coming decade, which is reflected in the record new installations since 2010. Wind energy, in particular, has proved its leading role among sustainable energy production means, by the accelerating rise in total installed [...] Read more.

Renewable energy is expected to experience epic growth in the coming decade, which is reflected in the record new installations since 2010. Wind energy, in particular, has proved its leading role among sustainable energy production means, by the accelerating rise in total installed capacity and by its consistently increasing trend. Taking a closer look at the history of wind power development, it is obvious that it has always been a matter of engineering taller turbines with longer blades. An increase in the tower height means an increase in the material used, thereby, impacting the initial construction cost and the total energy consumed. In the present study, a numerical investigation is carried out in order to actively compare conventional cylindrical shell towers with lattice towers in terms of material use, robustness and environmental impact. Lattice structures are proved to be equivalently competitive to conventional cylindrical solutions since they can be designed to be robust enough while being a much lighter tower in terms of material use. With detailed design, lattice wind turbine towers can constitute the new generation of wind turbine towers. Full article

(This article belongs to the Special Issue Advances in Wind Energy Structures)

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14 pages, 3116 KiB

Open AccessArticle

Influence of Clumps-Weighted Moorings on a Spar Buoy Offshore Wind Turbine

by Niccolo Bruschi, Giulio Ferri, Enzo Marino and Claudio Borri

Energies 2020, 13(23), 6407; https://doi.org/10.3390/en13236407 - 4 Dec 2020

Cited by 12 | Viewed by 3028

Abstract

The spar buoy platform for offshore wind turbines is the most utilized type and the OC3 Hywind system design is largely used in research. This system is usually moored with three catenary cables with 120° between each other. Adding clump weights to the [...] Read more.

The spar buoy platform for offshore wind turbines is the most utilized type and the OC3 Hywind system design is largely used in research. This system is usually moored with three catenary cables with 120° between each other. Adding clump weights to the mooring lines has an influence on the platform response and on the mooring line tension. However, the optimal choice for their position and weight is still an open issue, especially considering the multitude of sea states the platform can be exposed to. In this study, therefore, an analysis on the influence of two such variables on the platform response and on the mooring line tension is presented. FAST by the National Renewable Energy Laboratory (NREL) is used to perform time domain simulations and Response Amplitude Operators are adopted as the main indicators of the clump weights effects. Results show that the clump weight mass is not as influential as the position, which turns out to be optimal, especially for the Surge degree of freedom, when closest to the platform. Full article

(This article belongs to the Special Issue Advances in Wind Energy Structures)

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33 pages, 21580 KiB

Open AccessArticle

Buckling Analysis for Wind Turbine Tower Design: Thrust Load versus Compression Load Based on Energy Method

by Yang Ma, Pedro Martinez-Vazquez and Charalampos Baniotopoulos

Energies 2020, 13(20), 5302; https://doi.org/10.3390/en13205302 - 12 Oct 2020

Cited by 8 | Viewed by 5259

Abstract

Tubular steel towers are the most common design solution for supporting medium-to-high-rise wind turbines. Notwithstanding, historical failure incidence records reveal buckling modes as a common type of failure of shell structures. It is thus necessary to revisit the towers’ performance against bending-compression interactions [...] Read more.

Tubular steel towers are the most common design solution for supporting medium-to-high-rise wind turbines. Notwithstanding, historical failure incidence records reveal buckling modes as a common type of failure of shell structures. It is thus necessary to revisit the towers’ performance against bending-compression interactions that could unchain buckling modes. The present investigation scrutinises buckling performances of a cylindrical steel shell under combined load, by means of the energy method. Within the proposed framework, the differential equations to obtain dimensionless expressions showed the energy-displacement relations taking place along the shell surface. Furthermore, shell models integrated with initial imperfection have been embedded into finite element algorithms based on the Riks method. The results show buckling evolution paths largely affected by bending moments lead to section distortions (oval-shaped) that in turn change the strain energy dissipation routine and section curvature. The shell geometrical parameters also show a strong influence on buckling effects seemingly linked to a noticeable reduction of the shell bearing capacity during the combined loading scenarios. Full article

(This article belongs to the Special Issue Advances in Wind Energy Structures)

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22 pages, 9982 KiB

Open AccessArticle

Role of Inflow Turbulence and Surrounding Buildings on Large Eddy Simulations of Urban Wind Energy

by Giulio Vita, Syeda Anam Hashmi, Simone Salvadori, Hassan Hemida and Charalampos Baniotopoulos

Energies 2020, 13(19), 5208; https://doi.org/10.3390/en13195208 - 6 Oct 2020

Cited by 8 | Viewed by 3137

Abstract

Predicting flow patterns that develop on the roof of high-rise buildings is critical for the development of urban wind energy. In particular, the performance and reliability of devices largely depends on the positioning strategy, a major unresolved challenge. This work aims at investigating [...] Read more.

Predicting flow patterns that develop on the roof of high-rise buildings is critical for the development of urban wind energy. In particular, the performance and reliability of devices largely depends on the positioning strategy, a major unresolved challenge. This work aims at investigating the effect of variations in the turbulent inflow and the geometric model on the flow patterns that develop on the roof of tall buildings in the realistic configuration of the University of Birmingham’s campus in the United Kingdom (UK). Results confirm that the accuracy of Large Eddy Simulation (LES) predictions is only marginally affected by differences in the inflow mean wind speed and turbulence intensity, provided that turbulence is not absent. The effect of the presence of surrounding buildings is also investigated and found to be marginal to the results if the inflow is turbulent. The integral length scale is the parameter most affected by the turbulence characteristics of the inflow, while gustiness is only marginally influenced. This work will contribute to LES applications on the urban wind resource and their computational setup simplification. Full article

(This article belongs to the Special Issue Advances in Wind Energy Structures)

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19 pages, 14028 KiB

Open AccessArticle

Study of the Bearing Capacity of Stiffened Tall Offshore Wind Turbine Towers during the Erection Phase

by Yu Hu, Jian Yang and Charalampos Baniotopoulos

Energies 2020, 13(19), 5102; https://doi.org/10.3390/en13195102 - 1 Oct 2020

Cited by 11 | Viewed by 3003

Abstract

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 [...] Read more.

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. Full article

(This article belongs to the Special Issue Advances in Wind Energy Structures)

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21 pages, 3054 KiB

Open AccessArticle

Life Cycle Assessment of Tall Onshore Hybrid Steel Wind Turbine Towers

by Michaela Gkantou, Carlos Rebelo and Charalampos Baniotopoulos

Energies 2020, 13(15), 3950; https://doi.org/10.3390/en13153950 - 1 Aug 2020

Cited by 33 | Viewed by 6039

Abstract

Increasing needs for taller wind turbines with bigger capacities, intended for places with high wind velocities or at higher altitudes, have led to new technologies in the wind energy industry. A recently introduced structural system for onshore wind turbine towers is the hybrid [...] Read more.

Increasing needs for taller wind turbines with bigger capacities, intended for places with high wind velocities or at higher altitudes, have led to new technologies in the wind energy industry. A recently introduced structural system for onshore wind turbine towers is the hybrid steel tower. Comprehension of the environmental response of this hybrid steel structural system is warranted. Even though life cycle assessments (LCAs) for conventional wind turbine tubular towers exist, the environmental performance of this new hybrid structure has not been reported. The present paper examines the LCA of 185 m tall hybrid towers. Considerations made for the LCA procedure are meticulously described, including particular attention at the erection and transportation stage. The highest environmental impacts arise during the manufacturing stage followed by the erection stage. The tower is the component with the largest carbon emissions and energy requirements. The obtained LCA footprints of hybrid towers are also compared to the literature data on conventional towers, resulting in similar environmental impacts. Full article

(This article belongs to the Special Issue Advances in Wind Energy Structures)

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23 pages, 10523 KiB

Open AccessArticle

On the Wind Energy Resource above High-Rise Buildings

by Giulio Vita, Anina Šarkić-Glumac, Hassan Hemida, Simone Salvadori and Charalampos Baniotopoulos

Energies 2020, 13(14), 3641; https://doi.org/10.3390/en13143641 - 15 Jul 2020

Cited by 21 | Viewed by 4492

Abstract

One of the main challenges of urban wind energy harvesting is the understanding of the flow characteristics where urban wind turbines are to be installed. Among viable locations within the urban environment, high-rise buildings are particularly promising due to the elevated height and [...] Read more.

One of the main challenges of urban wind energy harvesting is the understanding of the flow characteristics where urban wind turbines are to be installed. Among viable locations within the urban environment, high-rise buildings are particularly promising due to the elevated height and relatively undisturbed wind conditions. Most research studies on high-rise buildings deal with the calculation of the wind loads in terms of surface pressure. In the present paper, flow pattern characteristics are investigated for a typical high-rise building in a variety of configurations and wind directions in wind tunnel tests. The aim is to improve the understanding of the wind energy resource in the built environment and give designers meaningful data on the positioning strategy of wind turbines to improve performance. In addition, the study provides suitable and realistic turbulence characteristics to be reproduced in physical or numerical simulations of urban wind turbines for several locations above the roof region of the building. The study showed that at a height of 10 m from the roof surface, the flow resembles atmospheric turbulence with an enhanced turbulence intensity above 10% combined with large length scales of about 200 m. Results also showed that high-rise buildings in clusters might provide a very suitable configuration for the installation of urban wind turbines, although there is a strong difference between the performance of a wind turbine installed at the centre of the roof and one installed on the leeward and windward corners or edges, depending on the wind direction. Full article

(This article belongs to the Special Issue Advances in Wind Energy Structures)

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