This thesis details potential design improvements by exploiting a new general grid model utilizing multiple wind and solar energy plants. A single renewable energy plant which relies on wind speed or solar insolation is unreliable because of the stochastic nature of weather patterns. To allow such a plant to match the requirements of a variable load some form of energy storage must be incorporated. To ensure a low loss of load expectation (LOLE) the size of this energy storage must be large to cope with the strong fluctuations in energy production. It is theorized that by using multiple renewable energy plants in separate areas of a region, the different weather conditions might approach a probabilistically independent relationship. The probability of energy generated from combined plants will then approach a Gaussian distribution by the central limit theorem. While maintaining the same LOLE as a single renewable plant this geographic separation model theoretically stabilizes the energy production and reduces the system variables: energy storage size, energy storage efficiency, and cumulative plant capacity. New generic weather models that incorporate levels of independence are created for wind speeds and solar insolations at different locations to support the geographic separation model. As the number of geographically separated plants increases and the weather approaches independence the system variables are reduced.

Fei, Fei. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2011. / Includes bibliographical references (leaves 102-106). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.

The purpose of this work is to develop a maximum power tracking control strategy for variable speed wind turbine systems. Modern wind turbine control systems are slow, and they depend on the design parameters of the turbine and use wind and/or rotor speed measurements as control variable inputs. The dependence on the accuracy of the measurement devices makes the controller less reliable. The proposed control scheme is based on the stiff system concept and provides a fast response and a dynamic solution to the complicated aerodynamic system. This control scheme provides a response to the wind changes without the knowledge of wind speed and turbine parameters. The system consists of a permanent magnet synchronous machine (PMSM), a passive rectifier, a dc/dc boost converter, a current controlled voltage source inverter, and a microcontroller that commands the dc/dc converter to control the generator for maximum power extraction. The microcontroller will also be able to control the current output of the three-phase inverter. In this work, the aerodynamic characteristics of wind turbines and the power conversion system topology are explained. The maximum power tracking control algorithm with a variable step estimator is introduced and the modeling and simulation of the wind turbine generator system using the MATLAB/SIMULINK® software is presented and its results show, at least in principle, that the maximum power tracking algorithm developed is suitable for wind turbine generation systems.

The purpose of this work is to develop a maximum power tracking control strategy for variable speed wind turbine systems. Modern wind turbine control systems are slow, and they depend on the design parameters of the turbine and use wind and/or rotor speed measurements as control variable inputs. The dependence on the accuracy of the measurement devices makes the controller less reliable. The proposed control scheme is based on the stiff system concept and provides a fast response and a dynamic solution to the complicated aerodynamic system. This control scheme provides a response to the wind changes without the knowledge of wind speed and turbine parameters. The system consists of a permanent magnet synchronous machine (PMSM), a passive rectifier, a dc/dc boost converter, a current controlled voltage source inverter, and a microcontroller that commands the dc/dc converter to control the generator for maximum power extraction. The microcontroller will also be able to control the current output of the three-phase inverter. In this work, the aerodynamic characteristics of wind turbines and the power conversion system topology are explained. The maximum power tracking control algorithm with a variable step estimator is introduced and the modeling and simulation of the wind turbine generator system using the MATLAB/SIMULINK® software is presented and its results show, at least in principle, that the maximum power tracking algorithm developed is suitable for wind turbine generation systems.

A wind resource assessment of two sites in the Waterloo region, WRESTRC and RIM Park, was conducted using wind speed, wind direction, temperature and pressure data collected from meteorological towers for over two years. The study was undertaken as part of the W3 Wind Energy Project, and the equipment was purchased from NRG Systems and R. M. Young Company. The data was filtered to reduce the effect of icing and tower shadow, and was analyzed using MATLAB software. Based on the mean wind speeds, small wind turbines less than 50 kW in capacity would be appropriate at both sites. Wind speeds tended to be stronger during the winter than the summer, and during the afternoon than the rest of the day. Both sites also exhibited a strong dominant wind direction -- from the northwest. Due to the terrain, the wind shear and turbulence intensity at WRESTRC were moderate when the wind flowed from the dominant direction, but very high from other directions. The wind shear and turbulence intensity at RIM Park were consistently moderate in all directions. Although the terrain seems more complex at WRESTRC, the wind speed distribution and estimated annual energy production were higher at WRESTRC than at RIM Park, which indicates that it is a more viable site. The estimated capacity factors ranged from 9.4% to 22% depending on the hub height, which is not nearly high enough to suggest a commercial wind farm would be viable at either site. A small 5 kW to 15 kW wind turbine in the Waterloo region could offset the electricity usage of an average home. A two-parameter power law model of wind shear was explored and compared with the standard one-parameter model. In terms of goodness-of-fit, the two-parameter model did perform better. But in terms of accuracy of extrapolation, it was not conclusively better or worse than a one-parameter model forced through the known data point closest to the prediction height. The relationship between turbulence intensity and measurement interval was examined. Since atmospheric flow is unsteady, they are not independent. The perceived turbulence intensity was found to increase exponentially with time intervals under 24 hours. Two linear regression-based Measure-Correlate-Predict methods were evaluated using long-term data from a weather station also at WRESTRC. The ordinary least squares method was considered the baseline given its simplicity. The variance ratio method improved upon it by ensuring that the variance of the wind speed distribution at the target site was preserved.

Wind energy provides an environmentally friendly and renewable source of electricity, that can help meet Canada's Kyoto commitments, help safeguard against future blackouts, reduce air pollution and create economic opportunities in the form of manufacturing jobs and land leases for farmers. From a land use planning perspective, however, wind turbines create challenges that municipalities and planners have to deal with more frequently. Ontario in particular lags behind countries such as Ireland and Australia in terms of providing a clear, equitable and comprehensive land use planning framework to deal with wind energy. <br /><br /> What is lacking in particular is a clear understanding of how Ontario municipalities are dealing with the issue of wind energy developments, whether the policies that are being developed adhere to good planning principles, what are the land use planning issues that are impacting wind energy development in Ontario and what are some recommendations that could be made to improve wind energy policies. A secondary goal of this thesis was to identify common elements of good wind energy planning frameworks that could be used to develop wind energy planning policies in the City of Stratford, which currently does not have any policies or a wind energy land use planning framework and is also where the author is employed as the City Planner. <br /><br /> To address this lack of information, this report focuses on the current state of wind energy planning policy development in southwestern Ontario and in particular; the types of wind energy planning frameworks have been developed in the world, the elements of "good" planning principles and frameworks and whether or not they are found in these frameworks, whether there are components of these policies that would be appropriate for wider adoption in Ontario and finally, what types of framework should the City of Stratford develop for wind energy? <br /><br /> To address these questions, a literature review was conducted on wind energy land use planning issues and examples of international wind energy planning guidelines were reviewed. Additionally, five southwestern Ontario municipalities with wind energy policies were selected as case studies and Planners and other wind energy stakeholders were interviewed. <br /><br /> This study found that the main issues and barriers surrounding wind energy planning policy development in Ontario are visual impact, lack of education and a lack of a municipal planning framework. It was also determined that, the public reaction to wind energy proposals in Southwestern Ontario has been mostly positive and the conflicts that have arisen have been in instances where wind turbines are proposed in the vicinity of recreational properties. In terms of a wind energy planning framework, southwestern Ontario municipalities have for the most part opted for General Official Plan policies supporting wind energy development in principle and directing its development to certain land use designations subject to a zoning by-law amendment. The planning frameworks in the case studies for the most part conform to good planning principles identified, however, there was a large variation between the municipalities in terms of the level of detail within the planning framework. Finally, it was determined that the City of Stratford Official Plan and Zoning By-law are inadequate in terms of policy and regulations for wind energy. <br /><br /> This study recommends that the Ontario Provincial Government should follow up on the Wind Energy Information Sheet and the recent Provincial Policy Statement with a comprehensive land use-planning framework for wind energy developments that should borrow on existing international guidelines that have been developed. This study also recommends that the City of Stratford should update its Official Plan to include policies that address wind energy generation, should initiate a study to determine if there are any areas within the City that are considered to be natural heritage views or areas that should be protected from the visual impacts of wind energy production, should investigate permitting wind energy facilities in certain industrial areas of the City, subject to a zoning by-law amendment and should work with the County of Perth to develop a common set of zoning by-law regulations for wind energy developments.

Wind energy resources, unlike dispatchable central station generation, produce power dependable on external irregular source and that is the incident wind speed which does not always blow when electricity is needed. This results in the variability, unpredictability, and uncertainty of wind resources. Therefore, the integration of wind facilities to utility electrical grid presents a major challenge to power system operator. Such integration has significant impact on the optimum power flow, transmission congestion, power quality issues, system stability, load dispatch, and economic analysis. Due to the irregular nature of wind power production, accurate prediction represents the major challenge to power system operators. Therefore, in this thesis two novel models are proposed for wind speed and wind power prediction. One proposed model is dedicated to short-term prediction (one-hour ahead) and the other involves medium term prediction (one-day ahead). The accuracy of the proposed models is revealed by comparing their results with the corresponding values of a reference prediction model referred to as the persistent model. Utility grid operation is not only impacted by the uncertainty of the future production of wind farms, but also by the variability of their current production and how the active and reactive power exchange with the grid is controlled. To address this particular task, a control technique for wind turbines, driven by doubly-fed induction generators (DFIGs), is developed to regulate the terminal voltage by equally sharing the generated/absorbed reactive power between the rotor-side and the grid-side converters. To highlight the impact of the new developed technique in reducing the power loss in the generator set, an economic analysis is carried out. Moreover, a new aggregated model for wind farms is proposed that accounts for the irregularity of the incident wind distribution throughout the farm layout. Specifically, this model includes the wake effect and the time delay of the incident wind speed of the different turbines on the farm, and to simulate the fluctuation in the generated power more accurately and more closer to real-time operation. Recently, wind farms with considerable output power ratings have been installed. Their integrating into the utility grid will substantially affect the electricity markets. This thesis investigates the possible impact of wind power variability, wind farm control strategy, wind energy penetration level, wind farm location, and wind power prediction accuracy on the total generation costs and close to real time electricity market prices. These issues are addressed by developing a single auction market model for determining the real-time electricity market prices.

Wind energy provides an environmentally friendly and renewable source of electricity, that can help meet Canada's Kyoto commitments, help safeguard against future blackouts, reduce air pollution and create economic opportunities in the form of manufacturing jobs and land leases for farmers. From a land use planning perspective, however, wind turbines create challenges that municipalities and planners have to deal with more frequently. Ontario in particular lags behind countries such as Ireland and Australia in terms of providing a clear, equitable and comprehensive land use planning framework to deal with wind energy. <br /><br /> What is lacking in particular is a clear understanding of how Ontario municipalities are dealing with the issue of wind energy developments, whether the policies that are being developed adhere to good planning principles, what are the land use planning issues that are impacting wind energy development in Ontario and what are some recommendations that could be made to improve wind energy policies. A secondary goal of this thesis was to identify common elements of good wind energy planning frameworks that could be used to develop wind energy planning policies in the City of Stratford, which currently does not have any policies or a wind energy land use planning framework and is also where the author is employed as the City Planner. <br /><br /> To address this lack of information, this report focuses on the current state of wind energy planning policy development in southwestern Ontario and in particular; the types of wind energy planning frameworks have been developed in the world, the elements of "good" planning principles and frameworks and whether or not they are found in these frameworks, whether there are components of these policies that would be appropriate for wider adoption in Ontario and finally, what types of framework should the City of Stratford develop for wind energy? <br /><br /> To address these questions, a literature review was conducted on wind energy land use planning issues and examples of international wind energy planning guidelines were reviewed. Additionally, five southwestern Ontario municipalities with wind energy policies were selected as case studies and Planners and other wind energy stakeholders were interviewed. <br /><br /> This study found that the main issues and barriers surrounding wind energy planning policy development in Ontario are visual impact, lack of education and a lack of a municipal planning framework. It was also determined that, the public reaction to wind energy proposals in Southwestern Ontario has been mostly positive and the conflicts that have arisen have been in instances where wind turbines are proposed in the vicinity of recreational properties. In terms of a wind energy planning framework, southwestern Ontario municipalities have for the most part opted for General Official Plan policies supporting wind energy development in principle and directing its development to certain land use designations subject to a zoning by-law amendment. The planning frameworks in the case studies for the most part conform to good planning principles identified, however, there was a large variation between the municipalities in terms of the level of detail within the planning framework. Finally, it was determined that the City of Stratford Official Plan and Zoning By-law are inadequate in terms of policy and regulations for wind energy. <br /><br /> This study recommends that the Ontario Provincial Government should follow up on the Wind Energy Information Sheet and the recent Provincial Policy Statement with a comprehensive land use-planning framework for wind energy developments that should borrow on existing international guidelines that have been developed. This study also recommends that the City of Stratford should update its Official Plan to include policies that address wind energy generation, should initiate a study to determine if there are any areas within the City that are considered to be natural heritage views or areas that should be protected from the visual impacts of wind energy production, should investigate permitting wind energy facilities in certain industrial areas of the City, subject to a zoning by-law amendment and should work with the County of Perth to develop a common set of zoning by-law regulations for wind energy developments.

Wind energy resources, unlike dispatchable central station generation, produce power dependable on external irregular source and that is the incident wind speed which does not always blow when electricity is needed. This results in the variability, unpredictability, and uncertainty of wind resources. Therefore, the integration of wind facilities to utility electrical grid presents a major challenge to power system operator. Such integration has significant impact on the optimum power flow, transmission congestion, power quality issues, system stability, load dispatch, and economic analysis. Due to the irregular nature of wind power production, accurate prediction represents the major challenge to power system operators. Therefore, in this thesis two novel models are proposed for wind speed and wind power prediction. One proposed model is dedicated to short-term prediction (one-hour ahead) and the other involves medium term prediction (one-day ahead). The accuracy of the proposed models is revealed by comparing their results with the corresponding values of a reference prediction model referred to as the persistent model. Utility grid operation is not only impacted by the uncertainty of the future production of wind farms, but also by the variability of their current production and how the active and reactive power exchange with the grid is controlled. To address this particular task, a control technique for wind turbines, driven by doubly-fed induction generators (DFIGs), is developed to regulate the terminal voltage by equally sharing the generated/absorbed reactive power between the rotor-side and the grid-side converters. To highlight the impact of the new developed technique in reducing the power loss in the generator set, an economic analysis is carried out. Moreover, a new aggregated model for wind farms is proposed that accounts for the irregularity of the incident wind distribution throughout the farm layout. Specifically, this model includes the wake effect and the time delay of the incident wind speed of the different turbines on the farm, and to simulate the fluctuation in the generated power more accurately and more closer to real-time operation. Recently, wind farms with considerable output power ratings have been installed. Their integrating into the utility grid will substantially affect the electricity markets. This thesis investigates the possible impact of wind power variability, wind farm control strategy, wind energy penetration level, wind farm location, and wind power prediction accuracy on the total generation costs and close to real time electricity market prices. These issues are addressed by developing a single auction market model for determining the real-time electricity market prices.

Next generation horizontal-axis wind turbines (HAWTs) will operate at very high wind speeds. Existing engineering approaches for modeling the flow phenomena are based on blade element theory, and cannot adequately account for 3-D separated, unsteady flow effects. Therefore, researchers around the world are beginning to model these flows using first principles-based computational fluid dynamics (CFD) approaches. In this study, an existing first principles-based Navier-Stokes approach is being enhanced to model HAWTs at high wind speeds. The enhancements include improved grid topology, implicit time-marching algorithms, and advanced turbulence models. The advanced turbulence models include the Spalart-Allmaras one-equation model, k-epsilon, k-omega and Shear Stress Transport (k-omega-SST) models. These models are also integrated with detached eddy simulation (DES) models. Results are presented for a range of wind speeds, for a configuration termed National Renewable Energy Laboratory Phase VI rotor, tested at NASA Ames Research Center. Grid sensitivity studies are also presented. Additionally, effects of existing transition models on the predictions are assessed. Data presented include power/torque production, radial distribution of normal and tangential pressure forces, root bending moments, and surface pressure fields. Good agreement was obtained between the predictions and experiments for most of the conditions, particularly with the Spalart-Allmaras-DES model.