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11 – 20 of over 3000M. Grujicic, S. Ramaswami, J.S. Snipes, R. Galgalikar, V. Chenna and R. Yavari
Wind energy is one of the most promising and the fastest growing alternative-energy production technologies, which have been developed in response to stricter environmental…
Abstract
Purpose
Wind energy is one of the most promising and the fastest growing alternative-energy production technologies, which have been developed in response to stricter environmental regulations, the depletion of fossil-fuel reserves, and the world's ever-growing energy needs. This form of alternative energy is projected to provide 20 percent of the US energy needs by 2030. For economic reasons, wind turbines (articulated structures that convert wind energy into electrical energy) are expected to operate, with only regular maintenance, for at least 20 years. However, some key wind turbine components (especially the gearbox) tend to wear down, malfunction and fail in a significantly shorter time, often three to five years after installation, causing an increase in the wind-energy cost and in the cost of ownership of the wind turbine. Clearly, to overcome this problem, a significant increase in long-term gearbox reliability needs to be achieved.
Design/methodology/approach
While purely empirical efforts aimed at identifying shortcomings in the current design of the gearboxes are of critical importance, the present work demonstrates that the use of advanced computational engineering analyses, like the finite-element stress analysis and a post-processing fatigue-life assessment analysis, can also be highly beneficial.
Findings
The results obtained in the present work clearly revealed how a variety of normal operating and extreme wind-loading conditions can influence the service-life of a wind-turbine gearbox in the case when the service-life is controlled by the gear-tooth bending-fatigue.
Originality/value
The present work attempts to make a contribution to the resolution of an important problem related to premature-failure and inferior reliability of wind-turbine gearboxes.
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Lingcheng Kong, Ling Liang, Jianhong Xu, Weisi Zhang and Weijun Zhu
Although the wind power industry has been booming in China during the last decade, the development of wind turbine aftermarket service is still lagging behind, which seriously…
Abstract
Purpose
Although the wind power industry has been booming in China during the last decade, the development of wind turbine aftermarket service is still lagging behind, which seriously affects the operational efficiency of wind farms. If wind turbine manufacturers get involved in the aftermarket, the service pricing policy will impact the profits of both the manufacturer and the wind farm. Therefore, it is necessary to discuss an optimal service pricing strategy in the wind turbine aftermarket and design a method to improve electricity generation efficiency through service contract design. The paper aims to discuss these issues.
Design/methodology/approach
In order to decide the maintenance quantity and channel effort level, the authors design a normal Stackelberg game and an efficiency value-added revenue-sharing contract and discuss two kinds of revenue increment sharing models under situations, in which the supply chain’s leaders are the wind farm and the wind turbine manufacturer, respectively.
Findings
The results show that in either case, there exist optimal power generation revenue-sharing ratios that can maximize profit. At the same time, the authors outline an optimal service pricing policy, maintenance demand policy and channel service effort-level policy. The results summarize the influences of wind aftermarket services on wind farms’ and wind turbine manufacturers’ profit, which provides managerial insights into the process of manufacturing servitization.
Practical implications
The manufacturer’s channel effort level will influence the power generation increments very much, so the authors have developed a mechanism to stimulate the manufacturer improving the efficiency of aftermarket services.
Originality/value
Taking the power generation increment revenue as the profit increment function, the authors discuss the influence of service price on the profit increment of the wind farm and the wind turbine manufacturer and also consider the influence of service price on the wind farms maintenance quantity and wind turbine manufacturers channel effort level.
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Mohd Zamri Ibrahim and Aliashim Albani
This paper aims to present a method of the wind turbine ranking, either stall or pitch-regulated wind turbine (WTG), to determine the suitability of wind turbine in a selected…
Abstract
Purpose
This paper aims to present a method of the wind turbine ranking, either stall or pitch-regulated wind turbine (WTG), to determine the suitability of wind turbine in a selected site.
Design/methodology/approach
The method included the wind park target capacity, the maximum hub-height, the standard rotor diameter and the characteristic of wind speed on the site. As the method had been applied to a wind park, with more than one wind turbine, the wake losses had been considered by subtracting the gross capacity factor. Besides, the turbine-site matching index (TSMI) was computed by dividing the net capacity factor with the total installed capital cost per kilowatt.
Findings
The components of the total installed capital cost were cost of turbine, installation, as well as operation and maintenance. Meanwhile, the target capacity index (TCI) was calculated by dividing the estimated wind park capacity with the target wind park capacity.
Originality/value
Both TSMI and TCI were used together to rank the wind turbines. Furthermore, a site in the eastern part of Kudat was selected as the case study site, where ten models of wind turbines were tested and ranked.
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Krzysztof Olasek, Maciej Karczewski, Michal Lipian, Piotr Wiklak and Krzysztof Józwik
A solution to increase the energy production rate of the wind turbine is proposed by forcing more air to move through the turbine working section. This can be achieved by…
Abstract
Purpose
A solution to increase the energy production rate of the wind turbine is proposed by forcing more air to move through the turbine working section. This can be achieved by equipping the rotor with a diffusing channel ended with a brim (diffuser augmented wind turbine – DAWT). The purpose of this paper is to design an experimental stand and perform the measurements of velocity vector fields through the diffuser and power characteristic of the wind turbine.
Design/methodology/approach
The experiments were carried out in a small subsonic wind tunnel at the Institute of Turbomachinery, Lodz University of Technology. An experimental stand design process as well as measurement results are presented. Model size sensitivity study was performed at the beginning. The experimental campaign consisted of velocity measurements by means of particle image velocimetry (PIV) and pneumatic pitot probe as well as torque and rotational velocity measurements.
Findings
Characteristics (power coefficient vs tip speed ratio) of the bare and shrouded wind turbine were obtained. The results show an increase in the wind turbine power up to 70-75 per cent by shrouding the rotor with a diffuser. The mechanisms responsible for such a power increase were well explained by the PIV and pneumatic measurement results revealing the nature of the flow through the diffuser.
Research limitations/implications
Experimental stand for wind turbine rotor testing is of a preliminary character. Most optimal methodology for obtaining power characteristic should be determined now. Presented results can serve as good input for choice of stable and reliable control system of wind turbine operational parameters.
Practical implications
A 3 kW DAWT is being developed at the Institute of Turbomachinery, Lodz University of Technology. Aim of the study is to design a compact and smart wind turbine optimised for low wind speed conditions. Developed wind turbine has a potential to be used as an effective element within a net of distributed generation, e.g. for domestic use.
Originality/value
Research carried out is the continuation of theoretical study began in 1970s. It was also inspired by practical solutions proposed by Japanese researchers few years ago. Presented paper is the summary of work devoted to optimisation of the DAWT for wind conditions in the region. Original solution has been applied, e.g. for experimental stand design (3D printing application).
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Becca Castleberry and John Scott Greene
Oklahoma has seen rapid growth in the development of wind energy over the past decade. Residents are concerned about the negative impacts of turbines such as noise or their…
Abstract
Purpose
Oklahoma has seen rapid growth in the development of wind energy over the past decade. Residents are concerned about the negative impacts of turbines such as noise or their appearance. This has raised concerns about property values. Thus, this paper aims to examine and quantify the overall impact of wind turbines upon real estate prices in Western Oklahoma.
Design/methodology/approach
Sales prices and the history of approximately 23,000 residential real estate records for both platted and unplatted properties in five counties were examined prior to the announcement of construction, after announcement and after construction. A hedonic analysis was undertaken to examine the real estate prices of the properties near wind farms.
Findings
While there may be isolated instances of lower property values for homes near wind turbines, results show no significant decreases in property values over homes near wind farms in the study area. Similar results are found for the unplatted properties.
Practical implications
This paper highlights that in spite of mixed attitudes toward wind farms and misconceptions regarding the link between turbines and property values, Oklahoma’s growing wind industry can continue to thrive without negatively impacting nearby home and land values and prices.
Originality/value
Although there have been numerous studies examining the relationship between wind turbine locations and real estate prices, no study has combined the large quantity of records (over 23,000) as well as both platted and unplatted locations.
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Abhijeet M. Malge and Prashant Maruti Pawar
Three different configurations of vertical axis wind turbines (VAWT) were fabricated by changing the storey height and their orientations. The purpose of this study is to find the…
Abstract
Purpose
Three different configurations of vertical axis wind turbines (VAWT) were fabricated by changing the storey height and their orientations. The purpose of this study is to find the effect of storey height and orientation on the performance of wind turbines. The multistory VAWT has three storeys. The first configuration had increased middle storey height, with 0–90-0 orientation of blades. Wherein the second turbine had equal storey heights. The third configuration had increased middle storey height with 0–120-240 orientation of blades. The blades were tested numerically and experimentally.
Design/methodology/approach
In this research work, prototypes of innovative multistory VAWT were built with different configurations and orientations. Three configurations of three-storey VAWT were fabricated by varying the height of storey of turbines. The orientations were made by keeping the storeys orthogonal to each other. Multistory VAWT was tested numerically and experimentally. ANSYS Fluent was used for computational fluid dynamic analysis of VAWT. K-epsilon model was used for numerical analysis of wind turbine. Experimentation was carried out in a wind tunnel for different tip speed ratios (TSR).
Findings
The three configurations of innovative multistory VAWT were tested numerically and experimentally for different TSR. It has been found that the VAWT with equal storey height had a better performance as compared to the other two configurations with increased middle storey height. The power coefficient of equal storey height VAWT was about 22%, wherein the power coefficient of turbines with reduced upper and lower storey height was between 5%–8%.
Research limitations/implications
The research work of multi-storey VAWT is very novel and original. The findings of the research will contribute to the existing work done in the field of VAWT. This will help other researchers to have insight into the development of multistory VAWT. The effect of storey height and configuration of multi-storey VAWT is studied numerically and experimentally, which concludes that the performance of equal storey is superior as compared to other configurations.
Practical implications
The multi-storey concept of VAWT was developed to counter the problem of wind direction. The blades of each storey were arranged orthogonal to each other. This helped to harness wind power irrespective of the direction of the wind. This will make the VAWT more sustainable and financially viable for domestic use.
Social implications
The turbines are specially designed for remotely located housed in rural areas where the power grid is not yet reached. Users can install the turbine on their rooftop and harness wind power of 100 W capacity. This will help them to make their life easy.
Originality/value
This research work is very original and first of a kind. The multistory concept of the wind turbine was checked for the effect of storey height and orientations of blades on its performance. Different configurations and orientations of the vertical axis were designed and developed for the first time.
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Stephen B. Harsh, Lynn Hamilton and Eric Wittenberg
As the interest in renewable energy increases and the number of federal and state incentives to support renewable energy has also grown in recent years, it seems worthwhile to…
Abstract
Purpose
As the interest in renewable energy increases and the number of federal and state incentives to support renewable energy has also grown in recent years, it seems worthwhile to explore the economics of using small wind energy systems to offset electricity costs on farms. The purpose of this paper is to explore the economics of small wind turbine installations on a dairy in Michigan through case study analysis.
Design/methodology/approach
An Excel‐based capital budgeting model is developed that contains two sub‐modules: one that estimates the value of the wind energy based on the measured wind resource, and an investment module that includes factors such as investment cost, financing parameters, sales of electricity; grants and tax credits and tax information. Cases using 20 and 50 kW turbine systems are analyzed.
Findings
The results of the case studies show that in a favorable wind resource, the federal tax and United States Department of Agriculture incentives as well as state policies such as net metering can make wind turbines a good investment with an internal rate of return of 12.5 percent in this example. However, if the wind resource is not sufficient, even favorable renewable energy policies will not offset the lost value of the power generation, and thus a wind turbine will be a poor investment decision. Farm businesses should carefully consider all factors before investing in a wind turbine.
Originality/value
This paper is the first in recent years to combine capital budgeting analysis, wind resource data and the implications of federal and state policies to determine if small wind turbines are a sound investment decision for farm businesses.
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Z.Q. Zhu and Jiabing Hu
Power‐electronic systems have been playing a significant role in the integration of large‐scale wind turbines into power systems due to the fact that during the past three decades…
Abstract
Purpose
Power‐electronic systems have been playing a significant role in the integration of large‐scale wind turbines into power systems due to the fact that during the past three decades power‐electronic technology has experienced a dramatic evolution. This second part of the paper aims to focus on a comprehensive survey of power converters and their associated control systems for high‐power wind energy generation applications.
Design/methodology/approach
Advanced control strategies, i.e. field‐oriented vector control and direct power control, are initially reviewed for wind‐turbine driven doubly fed induction generator (DFIG) systems. Various topologies of power converters, comprising back‐to‐back (BTB) connected two‐ and multi‐level voltage source converters (VSCs), BTB current source converters (CSCs) and matrix converters, are identified for high‐power wind‐turbine driven PMSG systems, with their respective features and challenges outlined. Finally, several control issues, viz., basic control targets, active damping control and sensorless control schemes, are elaborated for the machine‐ and grid‐side converters of PMSG wind generation systems.
Findings
For high‐power PMSG‐based wind turbines ranging from 3 MW to 5 MW, parallel‐connected 2‐level LV BTB VSCs are the most cost‐effective converter topology with mature commercial products, particularly for dual 3‐phase stator‐winding PMSG generation systems. For higher‐capacity wind‐turbine driven PMSGs rated from 5 MW to 10 MW, medium voltage multi‐level converters, such as 5‐level regenerative CHB, 3‐ and 4‐level FC BTB VSC, and 3‐level BTB VSC, are preferred. Among them, 3‐level BTB NPC topology is the favorite with well‐proven technology and industrial applications, which can also be extensively applicable with open‐end winding and dual stator‐winding PMSGs so as to create even higher voltage/power wind generation systems. Sensorless control algorithms based on fundamental voltages/currents are suggested to be employed in the basic VC/DPC schemes for enhancing the robustness in the entire PMSG‐based wind power generation system, due to that the problems related with electromagnetic interferences in the position signals and the failures in the mechanical encoders can be avoided.
Originality/value
This second part of the paper for the first time systematically reviews the latest state of arts with regard to power converters and their associated advanced control strategies for high‐power wind energy generation applications. It summarizes a variety of converter topologies with pros and cons highlighted for different power ratings of wind turbines.
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M. Grujicic, V. Chenna, R. Galgalikar, J.S. Snipes, S. Ramaswami and R. Yavari
A simple economic analysis has revealed that in order for wind energy to be a viable alternative, wind-turbines (convertors of wind energy into electrical energy) must be able to…
Abstract
Purpose
A simple economic analysis has revealed that in order for wind energy to be a viable alternative, wind-turbines (convertors of wind energy into electrical energy) must be able to operate for at least 20 years, with only regular maintenance. However, wind-turbines built nowadays do not generally possess this level of reliability and durability. Specifically, due to the malfunction and failure of drive-trains/gear-boxes, many wind-turbines require major repairs after only three to five years in service. The paper aims to discuss these issues.
Design/methodology/approach
The subject of the present work is the so-called white etch cracking, one of the key processes responsible for the premature failure of gear-box roller-bearings. To address this problem, a multi-physics computational methodology is developed and used to analyze the problem of wind-turbine gear-box roller-bearing premature-failure. The main components of the proposed methodology include the analyses of: first, hydrogen dissolution and the accompanying grain-boundary embrittlement phenomena; second, hydrogen diffusion from the crack-wake into the adjacent unfractured material; third, the inter-granular fracture processes; and fourth, the kinematic and structural response of the bearing under service-loading conditions.
Findings
The results obtained clearly revealed the operation of the white-etch cracking phenomenon in wind-turbine gear-box roller-bearings and its dependence on the attendant loading and environmental conditions.
Originality/value
The present work attempts to make a contribution to the resolution of an important problem related to premature-failure and inferior reliability of wind-turbine gearboxes.
Details
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Sally Sims and Peter Dent
The Government's aim to curb CO2 emissions from energy production has resulted in the growth of a new environmental feature; the wind turbine. Whilst this may help tackle climate…
Abstract
Purpose
The Government's aim to curb CO2 emissions from energy production has resulted in the growth of a new environmental feature; the wind turbine. Whilst this may help tackle climate change, there is concern that the visual and aural presence of these turbines could have a negative impact on house prices. Opinion studies undertaken within the UK appear to show significant variations in attitudes towards wind farms in different locations (in particular between Scotland and southern England) and at different stages during the development process. However, to date, no research has established the actual impact on proximate house values. Therefore, the purpose of this study, sponsored by the RICS, is to develop a methodology to measure the likely impact of onshore wind farms on house prices in the UK.
Design/methodology/approach
This study focused on residential property surrounding two wind farms in Cornwall. Transaction data for 1,052 house sales completed between 2000 and 2004 were obtained and analysed using regression modelling and comparative sales analysis. A second study undertook an analysis of the planning objections to wind farms in this location.
Findings
The analysis of transaction data found some correlation between distance from a wind farm, and value. However, the data were insufficiently detailed to draw any sound conclusions. The analysis of planning objections revealed that 95 percent of objections came from people living outside Cornwall.
Research limitations/implications
Whilst the methodology is sound, the available data were limited to house type and selling price, and therefore not sufficiently detailed to highlight any small changes in value.
Originality/value
The paper establishes general criteria which could be used to evaluate the potential impact of onshore wind farms on property values.
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