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New Modeling Tool Analyzes Floating Platform Concepts For Offshore Wind Turbines Fact Sheet
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Book Synopsis New Modeling Tool Analyzes Floating Platform Concepts for Offshore Wind Turbines (Fact Sheet). by :
Download or read book New Modeling Tool Analyzes Floating Platform Concepts for Offshore Wind Turbines (Fact Sheet). written by and published by . This book was released on 2011 with total page 1 pages. Available in PDF, EPUB and Kindle. Book excerpt: Researchers at the National Renewable Energy Laboratory (NREL) developed a new complex modeling and analysis tool capable of analyzing floating platform concepts for offshore wind turbines. The new modeling tool combines the computational methodologies used to analyze land-based wind turbines with the comprehensive hydrodynamic computer programs developed for offshore oil and gas industries. This new coupled dynamic simulation tool will enable the development of cost-effective offshore technologies capable of harvesting the rich offshore wind resources at water depths that cannot be reached using the current technology.
Book Synopsis New Modeling Tool Analyzes Floating Platform Concepts for Offshore Wind Turbines (Fact Sheet) by :
Download or read book New Modeling Tool Analyzes Floating Platform Concepts for Offshore Wind Turbines (Fact Sheet) written by and published by . This book was released on 2011 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Researchers at the National Renewable Energy Laboratory (NREL) developed a new complex modeling and analysis tool capable of analyzing floating platform concepts for offshore wind turbines. The new modeling tool combines the computational methodologies used to analyze land-based wind turbines with the comprehensive hydrodynamic computer programs developed for offshore oil and gas industries. Thisnew coupled dynamic simulation tool will enable the development of cost-effective offshore technologies capable of harvesting the rich offshore wind resources at water depths that cannot be reached using the current technology.
Book Synopsis Low Wind Speed Technology Phase II by :
Download or read book Low Wind Speed Technology Phase II written by and published by . This book was released on 2006 with total page 1 pages. Available in PDF, EPUB and Kindle. Book excerpt: This fact sheet describes a subcontract with Massachusetts Institute of Technology to study dynamic response simulations to evaluate floating platform concepts for offshore wind turbines.
Book Synopsis Low Wind Speed Technology Phase II by :
Download or read book Low Wind Speed Technology Phase II written by and published by . This book was released on 2006 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This fact sheet describes a subcontract with Massachusetts Institute of Technology to study dynamic response simulations to evaluate floating platform concepts for offshore wind turbines.
Book Synopsis Coupled Dynamic Modeling of Floating Wind Turbine Systems by :
Download or read book Coupled Dynamic Modeling of Floating Wind Turbine Systems written by and published by . This book was released on 2006 with total page 25 pages. Available in PDF, EPUB and Kindle. Book excerpt: This article presents a collaborative research program that the Massachusetts Institute of Technology (MIT) and the National Renewable Energy Laboratory (NREL) have undertaken to develop innovative and cost-effective floating and mooring systems for offshore wind turbines in water depths of 10-200 m. Methods for the coupled structural, hydrodynamic, and aerodynamic analysis of floating wind turbine systems are presented in the frequency domain. This analysis was conducted by coupling the aerodynamics and structural dynamics code FAST [4] developed at NREL with the wave load and response simulation code WAMIT (Wave Analysis at MIT) [15] developed at MIT. Analysis tools were developed to consider coupled interactions between the wind turbine and the floating system. These include the gyroscopic loads of the wind turbine rotor on the tower and floater, the aerodynamic damping introduced by the wind turbine rotor, the hydrodynamic damping introduced by wave-body interactions, and the hydrodynamic forces caused by wave excitation. Analyses were conducted for two floater concepts coupled with the NREL 5-MW Offshore Baseline wind turbine in water depths of 10-200 m: the MIT/NREL Shallow Drafted Barge (SDB) and the MIT/NREL Tension Leg Platform (TLP). These concepts were chosen to represent two different methods of achieving stability to identify differences in performance and cost of the different stability methods. The static and dynamic analyses of these structures evaluate the systems' responses to wave excitation at a range of frequencies, the systems' natural frequencies, and the standard deviations of the systems' motions in each degree of freedom in various wind and wave environments. This article in various wind and wave environments. This article explores the effects of coupling the wind turbine with the floating platform, the effects of water depth, and the effects of wind speed on the systems' performance. An economic feasibility analysis of the two concepts was also performed. Key cost components included the material and construction costs of the buoy; material and installation costs of the tethers, mooring lines, and anchor technologies; costs of transporting and installing the system at the chosen site; and the cost of mounting the wind turbine to the platform. The two systems were evaluated based on their static and dynamic performance and the total system installed cost. Both systems demonstrated acceptable motions, and have estimated costs of $1.4-$1.8 million, not including the cost of the wind turbine, the power electronics, or the electrical transmission.
Book Synopsis Floating Offshore Wind Energy by : Joao Cruz
Download or read book Floating Offshore Wind Energy written by Joao Cruz and published by Springer. This book was released on 2016-08-20 with total page 345 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides a state-of-the-art review of floating offshore wind turbines (FOWT). It offers developers a global perspective on floating offshore wind energy conversion technology, documenting the key challenges and practical solutions that this new industry has found to date. Drawing on a wide network of experts, it reviews the conception, early design stages, load & structural analysis and the construction of FOWT. It also presents and discusses data from pioneering projects. Written by experienced professionals from a mix of academia and industry, the content is both practical and visionary. As one of the first titles dedicated to FOWT, it is a must-have for anyone interested in offshore renewable energy conversion technologies.
Book Synopsis Station Keeping Analysis and Design for New Floating Offshore Wind Turbines by : Pau Trubat Casal
Download or read book Station Keeping Analysis and Design for New Floating Offshore Wind Turbines written by Pau Trubat Casal and published by . This book was released on 2020 with total page 166 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the framework of the reduction of the emissions of greenhouse gases, FOWT will be the technology that will exploit the wind resources in deep seas. In order to achieve a commercial deployment of this technology, a cost reduction is necessary through the optimization of the wind turbine by detailed studies to reduce its design uncertainties. One important aspect is the mooring system, which commonly represents between a 10 to 15 % of the capex. The present research aims to increase the knowledge of the design and analysis of the station keeping systems for floating offshore wind turbines. One of the most important aspects for a correct analysis and design of the mooring system is the simulation of the lines coupled with the floating structure and the wind turbine.In this dissertation, two different mooring line models coupled to a finite element model for the analysis of floating platforms are presented. The first model is a finite element model based on a slender rod approach. The model is extended to consider the rheological damping in the axial and bending direction within the constitutive equations of the problem. The second model is a new approach named quasi-dynamic model. The model assesses the static solution of the catenary equation but updates the line tension based on the external hydrodynamic forces and the inertial forces from the theoretical motion of the mooring line.In the design of mooring lines is important to consider and foresee the different phenomena and loads that can act along on the life span of these elements. Within these phenomena, the effects of the waves forces over the mooring lines o have been studied. The study analyzes the contribution of the wave forces over the mooring lines to determine when it is an important source of damage for the fatigue strength. Finally, new floating platform concepts need to be tested and analyzed in controlled conditions in order to validate the models used for the final designs. It is common that pool and flume basins do not present enough size for the catenary shape mooring systems because they cover a large extension. In this area, an optimization model for a truncated mooring system is presented. The truncated mooring system is formed by two types of chains to emulate the actual prototype mooring system of a scale spar platform in a narrow flume.
Book Synopsis Dynamics Modeling and Loads Analysis of an Offshore Floating Wind Turbine by : Jason Mark Jonkman
Download or read book Dynamics Modeling and Loads Analysis of an Offshore Floating Wind Turbine written by Jason Mark Jonkman and published by . This book was released on 2007 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The objectives of the work described in this report are to develop a comprehensive simulation tool that can model the coupled dynamic response of offshore floating wind turbines, verify the simulation capability through model-to-model comparisons, and apply the simulation tool in an integrated loads analysis for one of the promising floating support platform concepts.
Book Synopsis NREL Software Aids Offshore Wind Turbine Designs (Fact Sheet). by :
Download or read book NREL Software Aids Offshore Wind Turbine Designs (Fact Sheet). written by and published by . This book was released on 2013 with total page 1 pages. Available in PDF, EPUB and Kindle. Book excerpt: NREL researchers are supporting offshore wind power development with computer models that allow detailed analyses of both fixed and floating offshore wind turbines. While existing computer-aided engineering (CAE) models can simulate the conditions and stresses that a land-based wind turbine experiences over its lifetime, offshore turbines require the additional considerations of variations in water depth, soil type, and wind and wave severity, which also necessitate the use of a variety of support-structure types. NREL's core wind CAE tool, FAST, models the additional effects of incident waves, sea currents, and the foundation dynamics of the support structures.
Book Synopsis Design Load Analysis of Two Floating Offshore Wind Turbine Concepts by : Gordon M. Stewart
Download or read book Design Load Analysis of Two Floating Offshore Wind Turbine Concepts written by Gordon M. Stewart and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Much of the United States' wind resource is located over deep water where fixed-bottom offshore wind turbines are cost-prohibitive. To capture this energy, floating offshore wind turbines are being developed. However, current design standards do not explicitly cover issues relating to floating offshore wind turbines, which leads to risk and uncertainty in the design process. Two important issues that this dissertation investigates are the effect of simulation length and wind and wave misalignment on fatigue and ultimate loads. Experience in the offshore floating oil and gas industry has recommended simulation lengths of 3-6 hours, but the wind industry typically simulates between 10 minutes and one hour. The reasons for these simulation lengths is explored and recommendations for floating offshore wind turbines are made. The current offshore wind turbine design standard states that co-aligned wind and waves are a conservative ``worst-case'' scenario for loads, but this assertion may only hold true for fixed-bottom offshore turbines. A large operational design-space set of simulations are run to determine the impact of wind and wave misalignment on floating offshore turbines. Using results from both the simulation length and wind/wave misalignment study, probabilistic methods are used to determine a minimum set of simulations that is able to accurately characterize the loads response of floating platforms. Reduction of avian impacts have long been an important concern for the installation of wind farms. There is large uncertainty in the impacts of offshore wind farms on seabirds in the United States, as no offshore wind farms are currently operating. In this dissertation, experience from Europe is used to create a model of seabirds' interaction with fixed-bottom offshore wind farms. This model is used in a multi-objective optimization of the layout of a generic fixed-bottom offshore wind farm, considering both impacts on birds as well as power production. To simulate a farm comprised of floating offshore wind turbines, uncertainty in the positions of the turbines in the farm is introduced, and the layout is once again subjected to a multi-objective optimization.
Book Synopsis Dynamics Modeling, Simulation and Analysis of a Floating Offshore Wind Turbine by : Mohammed Khair Al-Solihat
Download or read book Dynamics Modeling, Simulation and Analysis of a Floating Offshore Wind Turbine written by Mohammed Khair Al-Solihat and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: " Floating Offshore Wind Turbines (FOWTs) are a promising technology to harness the abundant offshore wind energy resources in open ocean areas. A FOWT consists of a floating platform, the moorings, and the wind turbine structure (tower + Rotor-Nacelle Assembly (RNA)). The main focus of this thesis is to develop multibody dynamic models that integrate the structural dynamics, and hydrostatic, hydrodynamic, aerodynamic and mooring system loads. Special efforts are also devoted to characterize the mooring and hydrostatic loads as main sources of systems stiffness that shapes the dynamic behavior of the system. Two approaches for modeling the platform/tower dynamics are developed, a rigid multibody model and a coupled rigid-flexible multibody model. Both models treat the platform, nacelle and rotor as six-degrees-of-freedom (6-DOF) rigid bodies. However, modeling the wind turbine tower dynamics differs between these approaches. The rigid model considers the tower as a 6-DOF rigid body while the flexible model represents the tower as a three-dimensional (3D) tapered damped Euler-Bernoulli beam undergoing coupled general rigid body and elastic motions. In both approaches, the wind turbine drivetrain dynamics is also considered to capture the rotor spin response. The equations of motions of both models are derived symbolically using Lagrange's equations. The hydrostatic restoring loads are evaluated through development of a novel nonlinear hydrostatic approach. This approach allows evaluating the exact hydrostatic force and moment and position of the center of buoyancy as function of the platform displacement and finite rotation. New exact expressions for the water plane area restoring moments are developed. The hydrostatic stiffness matrix at an arbitrary position and orientation of the platform is subsequently derived. A quasi-static approach is then developed to determine the cable tensions of the single-segment and multi-segment mooring system configurations proposed to moor the platform to the seabed. The approach uses different governing equations, depending on whether the mooring lines partially rest on the seabed; are suspended; or fully taut. The exact mooring stiffness is subsequently derived and the influence of several mooring system parameters on the mooring system stiffness is investigated. As an alternative to the quasi-static cable model, a lumped mass cable model incorporating the cable-seabed contact effect is developed to integrate the cable dynamics into the FOWT system dynamics. The equations of motion of the mooring line nodes are assembled for the two mooring system configurations under consideration. A new methodology is also presented to calculate the equilibrium profile of the mooring line lying on a seabed as desirable initial conditions for solving the discretized cable equations of motion. Finally, the theoretical models are implemented through a large simulation tool to analyze the dynamic behavior of the spar FOWT system under study. A series of simulations under defined external loads (load cases) are performed to validate the dynamic models. The simulation results are compared with similar results obtained from well-known offshore wind design codes. The simulation results are found to be in very good agreement with the reported results. Numerical experiments are also performed to investigate the influence of the tower flexibility, mooring system configuration, tower twist and cable dynamics on the system dynamic behavior. The results show that the system responses obtained from the rigid body model under-predict the platform yaw response and exhibit less damping than those obtained from the flexible model. It is also found that the mooring system configuration choice does not influence the platform roll and pitch responses or tower elastic deflections." --
Book Synopsis Analysis and Study of Floating Offshore Wind Turbines by : Mehran Ahmadi
Download or read book Analysis and Study of Floating Offshore Wind Turbines written by Mehran Ahmadi and published by . This book was released on 2013 with total page 99 pages. Available in PDF, EPUB and Kindle. Book excerpt: Floating wind turbines offer a means to vastly expand the number of possible sites for offshore wind energy plants. By using a floating support platform secured by mooring lines, a wind turbine can be installed in waters exceeding the 30m depth that limits installation of conventional bottom-fixed offshore wind turbines. However, to be economically viable advances in floating offshore wind turbine system design and deployment are necessary to significantly reduce the cost and improve the reliability of floating wind turbines. This thesis develops a model-based simulation of floating offshore wind turbines in the MATLAB/Simulink environment. When necessary, the National Renewable Energy Laboratory's FAST code is used to conduct wind turbine simulations. Methods to link FAST to Simulink are developed in this thesis to accomplish this task. Modeling the wind turbine in the Simulink environment enables an efficient system level view of the entire wind turbine system. A number of design approaches to reduce the cost of offshore turbines are proposed in this thesis and studied in this modeling environment. A doubly-fed induction generator (DFIG) is proposed for wind turbine application. The primary advantage of DFIGs for wind turbines is that they allow the amplitude and frequency of their output voltages to be maintained at a constant value, no matter the wind speed. Because of this feature, DFIGs can be directly connected to the AC power network and remain synchronized at all times with that power network. Another advantage is the ability to control the power factor while keeping the power electronic devices in the wind turbine at a moderate size. In order to link a Simulink DFIG model to FAST, the model must be expressed in time domain. This thesis develops the time-domain modeling and simulation of DFIGs. Floating offshore wind turbines encounter greatly increased loading, which decreases fatigue life. One method to reduce the cost and mitigate offshore wind turbine structural loads is the application of structural control techniques commonly used in skyscrapers and bridges. Tuned mass dampers have been used to reduce loads in simulations of offshore wind turbines. This thesis discusses expanding the structural control methods by developing a set of optimum passive and active tuned mass dampers for offshore wind turbine platforms. Additionally, a new, high-efficiency, DC/DC bidirectional converter for a power quality conditioner for floating offshore wind turbines is proposed and analyzed. The power quality conditioner is used to smooth the variable turbine power and the DC/DC bidirectional converter acts as an interface circuit between the DC bus and ultracapacitors to manage the power flow during charging and discharging modes. Simulation results and experimental results are presented to verify the operation of the converter.
Book Synopsis Design, Analysis, Hybrid Testing and Orientation Control of a Floating Platform with Counter-Rotating Vertical-Axis Wind Turbines by : Samuel Adam Chinman Kanner
Download or read book Design, Analysis, Hybrid Testing and Orientation Control of a Floating Platform with Counter-Rotating Vertical-Axis Wind Turbines written by Samuel Adam Chinman Kanner and published by . This book was released on 2015 with total page 226 pages. Available in PDF, EPUB and Kindle. Book excerpt: The design and operation of two counter-rotating vertical-axis wind turbines on a floating, semi-submersible platform is studied. The technology, called the Multiple Integrated and Synchronized Turbines (MIST) platform has the potential to reduce the cost of offshore wind energy per unit of installed capacity. Attached to the platform are closely-spaced, counter-rotating turbines, which can achieve a higher power density per planform area because of synergistic interaction effects. The purpose of the research is to control the orientation of the platform and rotational speeds of the turbines by modifying the energy absorbed by each of the generators of the turbines. To analyze the various aspects of the platform and wind turbines, the analysis is drawn from the fields of hydrodynamics, electromagnetics, aerodynamics and control theory. To study the hydrodynamics of the floating platform in incident monochromatic waves, potential theory is utilized, taking into account the slow-drift yaw motion of the platform. Steady, second-order moments that are spatially dependent (i.e., dependent on the platform's yaw orientation relative to the incident waves) are given special attention since there are no natural restoring yaw moment. The aerodynamics of the counter-rotating turbines are studied in collaboration with researchers at the UC Berkeley Mathematics Department using a high-order, implicit, large-eddy simulation. An element flipping technique is utilized to extend the method to a domain with counter-rotating turbines and the effects from the closely-spaced turbines is compared with existing experimental data. Hybrid testing techniques on a model platform are utilized to prove the controllability of the platform in lieu of a wind-wave tank. A 1:82 model-scale floating platform is fabricated and tested at the UC Berkeley Physical-Model Testing Facility. The vertical-axis wind turbines are simulated by spinning, controllable actuators that can be updated in real-time of the model scale. Under certain wind and wave headings, it is possible to control the orientation of the platform in regular waves to maximize the power output from the turbines. A time-domain numerical simulation tool is able to confirm some of the experimental findings, taking into account the decoupled properties of the slow-drift hydrodynamics and wind turbine aerodynamics. Future platform designs are discussed, including the French-based, pre-commercial design from Nenuphar Wind, called the TwinFloat, which is closely related to concepts examined in the thesis.
Book Synopsis NREL Software Aids Offshore Wind Turbine Designs (Fact Sheet) by :
Download or read book NREL Software Aids Offshore Wind Turbine Designs (Fact Sheet) written by and published by . This book was released on 2013 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: NREL researchers are supporting offshore wind power development with computer models that allow detailed analyses of both fixed and floating offshore wind turbines. While existing computer-aided engineering (CAE) models can simulate the conditions and stresses that a land-based wind turbine experiences over its lifetime, offshore turbines require the additional considerations of variations inwater depth, soil type, and wind and wave severity, which also necessitate the use of a variety of support-structure types. NREL's core wind CAE tool, FAST, models the additional effects of incident waves, sea currents, and the foundation dynamics of the support structures.
Book Synopsis Loads Analysis of a Floating Offshore Wind Turbine Using Fully Coupled Simulation by :
Download or read book Loads Analysis of a Floating Offshore Wind Turbine Using Fully Coupled Simulation written by and published by . This book was released on 2007 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt: The vast deepwater wind resource represents a potential to use floating offshore wind turbines to power much of the world with renewable energy. Comprehensive simulation tools that account for the coupled excitation and response of the complete system, including the influences of wind-inflow, aerodynamics, structural dynamics, controls, and, for offshore systems, waves, currents, and hydrodynamics, are used to design and analyze wind turbines. The application of such tools in the analysis of floating offshore wind turbines has previously been investigated to only a limited extent. There are numerous possible concepts for floating offshore wind turbine platforms, including a variety of configurations currently used in the offshore oil and gas industries. Coupled analyses are needed to determine their technical and economic feasibility. This paper presents the use of fully coupled aero-hydro-servo-elastic simulation tools to perform a preliminary loads analysis of a 5-MW offshore wind turbine supported by a barge with catenary moorings, which is one of the many promising floating platform concepts.
Book Synopsis Reliability Analysis of a Spar Buoy-supported Floating Offshore Wind Turbine by : Abhinav Sultania
Download or read book Reliability Analysis of a Spar Buoy-supported Floating Offshore Wind Turbine written by Abhinav Sultania and published by . This book was released on 2010 with total page 144 pages. Available in PDF, EPUB and Kindle. Book excerpt: While wind energy has witnessed faster growth than any other renewable energy source in recent years, two issues -- the decreasing availability of large land expanses for new wind farms and transmission difficulties arising from siting wind farms in remote regions far from load centers -- have slowed down this growth considerably. Siting wind turbines offshore places the generating capacity closer to population and load centers; thus, reducing grid congestion. Also, at offshore sites, one can expect higher wind speeds, decreased turbulence, and reduced noise and visual impact constraints. Offshore wind turbines that have been built thus far have had foundations (such as monopiles or jacket structures) that have extended to the seabed. Such offshore wind turbines have thus been confined to shallow waters closer to the shore. Sites farther offshore provide better wind resources (i.e., less turbulence and smoother, stronger winds) while also reducing visual impact, noise, etc. However, deeper waters encountered at such sites make bottom-supported turbines less economical. Wind turbines mounted atop floating platforms are, thus, being considered for deeper water offshore sites. Various floating platform concepts are under consideration; the chief differences among them arise from the way they provide stability to counter the large mass of the rotor-nacelle assembly located high above the mean water level. Of these alternative concepts, the spar buoy platform is a deep draft structure with a low center of gravity, below the center of buoyancy. Reliability analysis of a spar buoy-supported floating offshore 5MW wind turbine based on stochastic simulation is the subject of this study. Environmental data from a selected deepwater reference site are employed in the numerical studies. Using time-domain simulations, the dynamic behavior of the coupled platform-turbine system is studied; statistics of tower and rotor loads as well as platform motions are estimated and critical combinations of wind speed and wave height identified.
Book Synopsis Three-dimensional Equivalent Static Analysis and Design Methodology of a Reinforced Concrete Floating Offshore Wind Turbine Platform by : Amy Carol Doman
Download or read book Three-dimensional Equivalent Static Analysis and Design Methodology of a Reinforced Concrete Floating Offshore Wind Turbine Platform written by Amy Carol Doman and published by . This book was released on 2014 with total page 302 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis presents a three-dimensional static analysis and design procedure for a floating offshore wind turbine support platform constructed of reinforced concrete. Results from a global performance analysis, which considers the dynamic interactions of wind and wave loading, from a conceptual case study by the American Bureau of Shipping are used to infer the equivalent static loading applied to the finite element model. Results from the analysis and applicable load combinations obtained from relevant design guidelines are used to design a floating concrete platform structure that includes precast and cast-in-place components as well as post-tensioning. The proposed concrete platform is a tri-floater, semi-submersible structure that consists of a cylindrical central core column to support the wind turbine tower, stabilized by the three buoyancy columns and a rigid pontoon base. The floating reinforced concrete support platform is shown to be an economically viable option when compared to steel platforms. Floating offshore wind turbine technology is a relatively new multi-disciplinary field of engineering where current design concepts primarily utilize steel floating support platforms. Reinforced concrete is advantageous over steel because of the durability of concrete exposed to a marine environment. Construction recommendations are discussed, as are social and economic considerations for floating offshore wind turbines.
