During the past decade, the demand for clean renewable energy continues to rise drastically in Europe, the US, and other countries. Wind energy in the ocean can possibly be one of those future renewable clean energy sources as long it is economically feasible and technologically manageable. So far, most of the offshore wind farm research has been limited to fixed platforms in shallow-water areas. In the water depth deeper than 30m, however, floating-type wind farms tend to be more feasible. Then, the overall design and engineering becomes more complicated than fixed platforms including the coupled dynamics of platforms, mooring lines, and blades. In the present study, a numerical time-domain model has been developed for the fully coupled dynamic analysis of an offshore floating wind turbine system including blade-rotor dynamics and platform motions. As a test case, the TLP-type floater system with 3 blades of 70-m diameter designed by the National Renewable Energy Laboratory (NREL) is selected to analyze the dynamic coupling effects among floating system, mooring lines, and wind turbine. The performance of the selected system in a typical wind-wave-current condition has been simulated and analyzed. A similar study for the floater and rotor coupled dynamic analysis was conducted by MIT and NREL. However, in the present case, the dynamic coupling between platform and mooring lines are also considered in addition to the rotor-floater dynamic coupling. It is seen that the rotor-floater coupling effects increase with wind velocity and blade size. The increased coupling effects tend to increase the dynamic tension of TLP tethers. The developed technology and numerical tool are applicable to the new offshore floating wind farms planned in the future.

Offshore wind farms are widely considered to become a cornerstone of energy transition for securing energy supply and tackling climate change simultaneously. But recent developments have demonstrated that the siting of offshore wind farms is far from being conflict-free, evoking confrontations with a number of stakeholder interests. Such real-life evidence implies a reductio ad absurdum, as offshore wind farms are generally supposed to be less contested than the ones onshore and therefore more convenient for local communities. By drawing on two case studies in Scotland and Germany (Argyll Array / Baltic 1), this thesis examines various conflicts that emerge from the siting of offshore wind farms and compares their underlying causes as well as their implications and institutional consideration in the planning process. In order to understand the conflicts over offshore wind farms, the research employs the epistemological framework of ‘space-related conflicts’ which turns the attention to conflicting interests, values and practices of affected actors as well as to the significance of structural and spatial conditions. Throughout the thesis, it will be argued that it is not the wind farms per se that are contested, but that the conflicts rather revolve around the places and spaces which are meant to be changed by the siting of offshore wind farms. The findings show that both case studies reflect similar conflicts, where adverse impacts on coastal tourism and environmental impacts turned out to be the key issues for local opponents from the public. However, even though key controversies are comparable, major differences result from the rationales that opponents invoke to substantiate their concerns and more dominantly from the existing planning frameworks which pre-structure the power relations and dynamics of public engagement. The comparative study concludes by suggesting some policy recommendations for future practices of dealing with affected actors. Therefore, the research findings do not just provide a contribution to the theoretical debates about the formation of resistance to renewables, but they also present practical implications relevant to policy-makers.

Wind energy development and its stigma of avian mortality provide a case for exploring the complexities that can occur between science, law, politics, and planning. The present method of measuring mortality appears flawed and may hamper the ability of resource agencies, the public, and industry in making educated decisions about siting wind farms and protecting species. The U.S. Fish and Wildlife Service has the ability to take an active role and affect a project already constructed. The Migratory Bird Treaty Act appears to keep the issue of avian mortality within the minds of wind energy developers. Protecting species on the brink of extinction is codified in the Endangered Species Act, which seems to be well suited for protecting most species. The significance of avian mortality can be linked to public perceptions. The industry in Texas has taken the approach of not sharing avian-related data, except in very few instances. Providing such substantial federal incentives through the Production Tax Credit rather than direct federal funding bypasses the National Environmental Policy Act and its requirement that federal governments consider impacts to the environment. / text

This dissertation addresses the modeling of wind turbine systems (WTS) and wind farms. The WTS reliability model provides the generation state space of a WTS. The generation states are derived from the combinations of the wind states from given wind data and the condition states of each component in a WTS. Wake effect is accounted when there are neighboring WTSs. The results of the reliability model of a WTS are associated with the generation states of the WTS, which include the probability, transition rates to other states, frequency of transitions to other states, and duration. The reliability model of the wind farm is derived by combining the wind states, WTS states and the distribution line states. The results of the reliability model of a wind farm are associated with the generation states of the wind farm, which include the probability, transition rates to other states, frequency to other states, and duration. The reliability model of the wind turbine system and the reliability model of the wind farm presented in this dissertation bring contribution to the planning and operation of bulk power systems with wind farm integration. The developed models can provide the system operator with clear reliability indices in terms of generation states of wind turbine systems and wind farms along with their probability, duration and frequency of transitions.

This research study presents the wind resource assessment at two potential onshore wind sites at the Western Cape of South Africa for small and large scale wind energy generation. It is anticipated that by virtue of the enormous wind resources prevalent along the South Africa West Coast, it is economical and cost effective to generate electricity from the wind to offset the increasing cost of energy generation from non-renewable sources (coal-fired, nuclear, gas etc.) which are the major source of power generation. Despite the environmental benefit and economic potentials of the wind energy, its variability and the inability to accurately predict (estimate) the long term energy generation potentials usually lead to difficulties in the selection and development of a suitable wind site for any proposed wind farm project(s) in the country.

Atmospheric boundary layer flows around wind turbines distributed in a large wind farm can be examined by the use of large eddy simulation (LES), which is based on the assumption that large eddies in the flow are anisotropic and depend on the mean flow and the configuration geometry, while smaller eddies are isotropic and homogeneous, and can be modeled via subgrid scale models. In this thesis, a pseudo-spectral LES code with inflow conditions imposed through a precursor concurrent simulation is utilized to model the flow around a single wind turbine or a large wind farm operating in thermally-stratified conditions. The effect of the wind turbines on humidity is monitored through an additional scalar convection equation. It is found that on average, the effect of an individual wind turbine on the humidity is less than 1%, while the effect of the wind farm on humidity can reach 1-2% in the cumulative wakes.

abstract: This research work uses the Weather Research and Forecasting Model to study the effect of large wind farms with an area of 900 square kilometers and a high power density of 7.58 W/m2 on regional climate. Simulations were performed with a wind farm parameterization scheme turned on in south Oregon. Control cases were also run with the parameterization scheme turned off. The primary emphasis was on offshore wind farms. Some analysis on onshore wind farms was also performed. The effects of these wind farms were studied on the vertical profiles of temperature, wind speed, and moisture as well as on temperature and on wind speed near the surface and at hub height. The effects during the day and at night were compared. Seasonal variations were also studied by performing simulations in January and in July. It was seen that wind farms produce a reduction in wind speed at hub height and that the downward propagation of this reduction in wind speed lessens as the atmosphere becomes more stable. In all the cases studied, the wind farms produced a warming effect near the surface, with greater atmospheric stability leading to higher near-surface temperatures. It was also observed that wind farms caused a drying effect below the hub height and a moistening effect above it, because they had facilitated vertical transport of moisture in the air from the lower layers of the atmosphere to the layers of the atmosphere above the wind farm. / Dissertation/Thesis / Masters Thesis Mechanical Engineering 2016

Published Article / The world is increasingly being misused by its inhabitants by the wasteful manner that its resources are utilized and the amount of pollution that is generated in the environment. This practice is unsustainable and it is incumbent on the present generation of decision-makers to rectify this phenomenon if our descendants are to have an opportunity to live life in the same manner as we do. Special emphasis should be placed on a reduction in the amount of air pollution that is created by electrical power generating plants, as well as the manner in which potable water is utilized and wasted. In this article the local situation with respect to the generation and use of electrical energy and water is discussed. It is encouraging to see that the National Government is taking strong steps to address these problems. Yet, it might not have the required ability to finance these efforts fully.

A spectral wave model (SWAN) coupled with a depth averaged hydrodynamic model (Delft3D) was used to understand the wave and flow dynamics of the Kingston Basin of Lake Ontario during large winter storm events. This model was then used to assess the impact of an offshore wind farm in the Kingston Basin. Results over different model domains with various forcing methods were compared to achieve the highest correlation with wave, current and water level observations from several locations. Storm events were modelled over the complex bathymetry of the basin and results were verified using wave and current profiler data collected during the winters of 2009-10 and 2011-12. Waves were composed of both locally generated wind sea and swell from the main basin of Lake Ontario, while flows throughout the Kingston Basin showed a complex circulation pattern. This circulation is composed of several wind-driven gyres, which are magnified during storm events. The impact of waves on the circulation patterns within the basin is highest in shallow areas where wave breaking drives circulation. To simulate a wind farm, a transmission coefficient was used in the wave model to represent the effects on waves, and an energy loss term was added to the hydrodynamic momentum equations to represent the added drag of the piles on the circulation. The results indicate that the coastal areas in eastern Lake Ontario will be minimally affected. The headlands of Big Sandy Bay, Wolfe Island, could see the largest coastal effects with changes in significant wave height predicted to be < 2%. The majority of impacts to circulation occur in the near-field, with changes in current magnitude of < 0.08 m s-1 (up to 50%). Areas near Wolfe Island exhibit changes of ~ 0.05 m s-1 (30 %), although overall circulation patterns throughout the basin are not affected. The majority of changes to surface waves and wind-driven currents are due to wind farm position with respect to wind direction and the re-direction of flows and waves as they pass through the wind farm. / Thesis (Master, Civil Engineering) -- Queen's University, 2013-09-30 09:30:01.042

Πολλές χώρες υποστηρίζουν και προωθούν την ανάπτυξη των χερσαίων και των υπεράκτιων αιολικών πάρκων ως μέρος της στρατηγικής τους για την εδραίωση ανανεώσιμων πηγών ενέργειας. Αυτό έχει ως αποτέλεσμα την ταχεία αύξηση των προτάσεων κατασκευής αιολικών πάρκων τα με προοπτική ακόμη μεγαλύτερης αύξησης. Ωστόσο, πρόσφατες μελέτες που έχουν διεξαχθεί από το Υπουργείο Άμυνας του Ηνωμένου Βασιλείου (UK Ministry of Defence) έχουν εξάγει ενδιαφέροντα συμπεράσματα τα οποία βρίσκονται στον αντίποδα της απροβλημάτιστης εδραίωσής τους, δηλαδή ότι τα αιολικά πάρκα μπορούν να επιδράσουν αρνητικά την απόδοση των στρατιωτικών και πολιτικών συστημάτων RADAR τα οποία λειτουργούν μέσα στη δραστική εμβέλεια τους και επιπλέον έχουν Οπτική Επαφή (Line Of Sight) με τις ανεμογεννήτριες. Κατά συνέπεια, λόγω της ευρείας διάδοσης της εκμετάλλευσης αιολικών πάρκων ανά τον κόσμο, είναι σημαντικό να αναπτυχθεί παράλληλα μια ισχυρή τεχνική κατανόηση σχετικά με την αλληλεπίδραση των ανεμογεννητριών και των RADAR άμυνας ή επίθεσης. Αυτή η κατανόηση θα ενισχύσει τις δυνατότητες για τη βελτιστοποίηση της χωροθέτησης των μελλοντικών αιολικών πάρκων που προτείνονται για εγκατάσταση, με σκοπό την ελαχιστοποίηση των αρνητικών επιπτώσεων. / --