WorldWideScience

Sample records for wind sensitivity study

  1. Sensitivity analysis of floating offshore wind farms

    International Nuclear Information System (INIS)

    Castro-Santos, Laura; Diaz-Casas, Vicente

    2015-01-01

    Highlights: • Develop a sensitivity analysis of a floating offshore wind farm. • Influence on the life-cycle costs involved in a floating offshore wind farm. • Influence on IRR, NPV, pay-back period, LCOE and cost of power. • Important variables: distance, wind resource, electric tariff, etc. • It helps to investors to take decisions in the future. - Abstract: The future of offshore wind energy will be in deep waters. In this context, the main objective of the present paper is to develop a sensitivity analysis of a floating offshore wind farm. It will show how much the output variables can vary when the input variables are changing. For this purpose two different scenarios will be taken into account: the life-cycle costs involved in a floating offshore wind farm (cost of conception and definition, cost of design and development, cost of manufacturing, cost of installation, cost of exploitation and cost of dismantling) and the most important economic indexes in terms of economic feasibility of a floating offshore wind farm (internal rate of return, net present value, discounted pay-back period, levelized cost of energy and cost of power). Results indicate that the most important variables in economic terms are the number of wind turbines and the distance from farm to shore in the costs’ scenario, and the wind scale parameter and the electric tariff for the economic indexes. This study will help investors to take into account these variables in the development of floating offshore wind farms in the future

  2. Sensitivity study of surface wind flow of a limited area model simulating the extratropical storm Delta affecting the Canary Islands

    OpenAIRE

    Marrero, C.; Jorba, O.; Cuevas, E.; Baldasano, J. M.

    2009-01-01

    In November 2005 an extratropical storm named Delta affected the Canary Islands (Spain). The high sustained wind and intense gusts experienced caused significant damage. A numerical sensitivity study of Delta was conducted using the Weather Research & Forecasting Model (WRF-ARW). A total of 27 simulations were performed. Non-hydrostatic and hydrostatic experiments were designed taking into account physical parameterizations and geometrical factors (size and position of the outer domain, d...

  3. Sensitivity study of surface wind flow of a limited area model simulating the extratropical storm Delta affecting the Canary Islands

    Directory of Open Access Journals (Sweden)

    C. Marrero

    2009-04-01

    Full Text Available In November 2005 an extratropical storm named Delta affected the Canary Islands (Spain. The high sustained wind and intense gusts experienced caused significant damage. A numerical sensitivity study of Delta was conducted using the Weather Research & Forecasting Model (WRF-ARW. A total of 27 simulations were performed. Non-hydrostatic and hydrostatic experiments were designed taking into account physical parameterizations and geometrical factors (size and position of the outer domain, definition or not of nested grids, horizontal resolution and number of vertical levels. The Factor Separation Method was applied in order to identify the major model sensitivity parameters under this unusual meteorological situation. Results associated to percentage changes relatives to a control run simulation demonstrated that boundary layer and surface layer schemes, horizontal resolutions, hydrostaticity option and nesting grid activation were the model configuration parameters with the greatest impact on the 48 h maximum 10 m horizontal wind speed solution.

  4. Global sensitivity analysis in wind energy assessment

    Science.gov (United States)

    Tsvetkova, O.; Ouarda, T. B.

    2012-12-01

    Wind energy is one of the most promising renewable energy sources. Nevertheless, it is not yet a common source of energy, although there is enough wind potential to supply world's energy demand. One of the most prominent obstacles on the way of employing wind energy is the uncertainty associated with wind energy assessment. Global sensitivity analysis (SA) studies how the variation of input parameters in an abstract model effects the variation of the variable of interest or the output variable. It also provides ways to calculate explicit measures of importance of input variables (first order and total effect sensitivity indices) in regard to influence on the variation of the output variable. Two methods of determining the above mentioned indices were applied and compared: the brute force method and the best practice estimation procedure In this study a methodology for conducting global SA of wind energy assessment at a planning stage is proposed. Three sampling strategies which are a part of SA procedure were compared: sampling based on Sobol' sequences (SBSS), Latin hypercube sampling (LHS) and pseudo-random sampling (PRS). A case study of Masdar City, a showcase of sustainable living in the UAE, is used to exemplify application of the proposed methodology. Sources of uncertainty in wind energy assessment are very diverse. In the case study the following were identified as uncertain input parameters: the Weibull shape parameter, the Weibull scale parameter, availability of a wind turbine, lifetime of a turbine, air density, electrical losses, blade losses, ineffective time losses. Ineffective time losses are defined as losses during the time when the actual wind speed is lower than the cut-in speed or higher than the cut-out speed. The output variable in the case study is the lifetime energy production. Most influential factors for lifetime energy production are identified with the ranking of the total effect sensitivity indices. The results of the present

  5. Probabilistic Design of Wind Turbine Structures: Design Studies and Sensitivities to Model Parameters

    DEFF Research Database (Denmark)

    NJOMO WANDJI, Wilfried

    : decrease of conservatism level, improvement of design procedures, and development of innovative structural systems that suit well for large wind turbines. The increasing size of the structure introduces new problems that were not present for small structures. These problems include: (i) the preparation...... substructures. In addition to being aggressive, conditions for offshore environments and the associated models are highly uncertain. Appropriate statistical methodologies should be used in order to design robust structures, which are structures whose engineering performance is not significantly affected....... These research areas are differentially implemented through tasks on various wind turbine structures (shaft, jacket, semi-floater, monopile, and grouted joint). In particular the following research questions are answered: How are extreme and fatigue loads on a given structure influenced by the design of other...

  6. Weather Research and Forecasting Model Wind Sensitivity Study at Edwards Air Force Base, CA

    Science.gov (United States)

    Watson, Leela R.; Bauman, William H., III; Hoeth, Brian

    2009-01-01

    This abstract describes work that will be done by the Applied Meteorology Unit (AMU) in assessing the success of different model configurations in predicting "wind cycling" cases at Edwards Air Force Base, CA (EAFB), in which the wind speeds and directions oscillate among towers near the EAFB runway. The Weather Research and Forecasting (WRF) model allows users to choose among two dynamical cores - the Advanced Research WRF (ARW) and the Non-hydrostatic Mesoscale Model (NMM). There are also data assimilation analysis packages available for the initialization of the WRF model - the Local Analysis and Prediction System (LAPS) and the Advanced Regional Prediction System (ARPS) Data Analysis System (ADAS). Having a series of initialization options and WRF cores, as well as many options within each core, creates challenges for local forecasters, such as determining which configuration options are best to address specific forecast concerns. The goal of this project is to assess the different configurations available and determine which configuration will best predict surface wind speed and direction at EAFB.

  7. Mapping seabird sensitivity to offshore wind farms.

    Directory of Open Access Journals (Sweden)

    Gareth Bradbury

    Full Text Available We present a Geographic Information System (GIS tool, SeaMaST (Seabird Mapping and Sensitivity Tool, to provide evidence on the use of sea areas by seabirds and inshore waterbirds in English territorial waters, mapping their relative sensitivity to offshore wind farms. SeaMaST is a freely available evidence source for use by all connected to the offshore wind industry and will assist statutory agencies in assessing potential risks to seabird populations from planned developments. Data were compiled from offshore boat and aerial observer surveys spanning the period 1979-2012. The data were analysed using distance analysis and Density Surface Modelling to produce predicted bird densities across a grid covering English territorial waters at a resolution of 3 km×3 km. Coefficients of Variation were estimated for each grid cell density, as an indication of confidence in predictions. Offshore wind farm sensitivity scores were compiled for seabird species using English territorial waters. The comparative risks to each species of collision with turbines and displacement from operational turbines were reviewed and scored separately, and the scores were multiplied by the bird density estimates to produce relative sensitivity maps. The sensitivity maps reflected well the amassed distributions of the most sensitive species. SeaMaST is an important new tool for assessing potential impacts on seabird populations from offshore development at a time when multiple large areas of development are proposed which overlap with many seabird species' ranges. It will inform marine spatial planning as well as identifying priority areas of sea usage by marine birds. Example SeaMaST outputs are presented.

  8. Mapping seabird sensitivity to offshore wind farms.

    Science.gov (United States)

    Bradbury, Gareth; Trinder, Mark; Furness, Bob; Banks, Alex N; Caldow, Richard W G; Hume, Duncan

    2014-01-01

    We present a Geographic Information System (GIS) tool, SeaMaST (Seabird Mapping and Sensitivity Tool), to provide evidence on the use of sea areas by seabirds and inshore waterbirds in English territorial waters, mapping their relative sensitivity to offshore wind farms. SeaMaST is a freely available evidence source for use by all connected to the offshore wind industry and will assist statutory agencies in assessing potential risks to seabird populations from planned developments. Data were compiled from offshore boat and aerial observer surveys spanning the period 1979-2012. The data were analysed using distance analysis and Density Surface Modelling to produce predicted bird densities across a grid covering English territorial waters at a resolution of 3 km×3 km. Coefficients of Variation were estimated for each grid cell density, as an indication of confidence in predictions. Offshore wind farm sensitivity scores were compiled for seabird species using English territorial waters. The comparative risks to each species of collision with turbines and displacement from operational turbines were reviewed and scored separately, and the scores were multiplied by the bird density estimates to produce relative sensitivity maps. The sensitivity maps reflected well the amassed distributions of the most sensitive species. SeaMaST is an important new tool for assessing potential impacts on seabird populations from offshore development at a time when multiple large areas of development are proposed which overlap with many seabird species' ranges. It will inform marine spatial planning as well as identifying priority areas of sea usage by marine birds. Example SeaMaST outputs are presented.

  9. INFERENCE AND SENSITIVITY IN STOCHASTIC WIND POWER FORECAST MODELS.

    KAUST Repository

    Elkantassi, Soumaya

    2017-10-03

    Reliable forecasting of wind power generation is crucial to optimal control of costs in generation of electricity with respect to the electricity demand. Here, we propose and analyze stochastic wind power forecast models described by parametrized stochastic differential equations, which introduce appropriate fluctuations in numerical forecast outputs. We use an approximate maximum likelihood method to infer the model parameters taking into account the time correlated sets of data. Furthermore, we study the validity and sensitivity of the parameters for each model. We applied our models to Uruguayan wind power production as determined by historical data and corresponding numerical forecasts for the period of March 1 to May 31, 2016.

  10. INFERENCE AND SENSITIVITY IN STOCHASTIC WIND POWER FORECAST MODELS.

    KAUST Repository

    Elkantassi, Soumaya; Kalligiannaki, Evangelia; Tempone, Raul

    2017-01-01

    Reliable forecasting of wind power generation is crucial to optimal control of costs in generation of electricity with respect to the electricity demand. Here, we propose and analyze stochastic wind power forecast models described by parametrized stochastic differential equations, which introduce appropriate fluctuations in numerical forecast outputs. We use an approximate maximum likelihood method to infer the model parameters taking into account the time correlated sets of data. Furthermore, we study the validity and sensitivity of the parameters for each model. We applied our models to Uruguayan wind power production as determined by historical data and corresponding numerical forecasts for the period of March 1 to May 31, 2016.

  11. On the sensitivity of numerical weather prediction to remotely sensed marine surface wind data - A simulation study

    Science.gov (United States)

    Cane, M. A.; Cardone, V. J.; Halem, M.; Halberstam, I.

    1981-01-01

    The reported investigation has the objective to assess the potential impact on numerical weather prediction (NWP) of remotely sensed surface wind data. Other investigations conducted with similar objectives have not been satisfactory in connection with a use of procedures providing an unrealistic distribution of initial errors. In the current study, care has been taken to duplicate the actual distribution of information in the conventional observing system, thus shifting the emphasis from accuracy of the data to the data coverage. It is pointed out that this is an important consideration in assessing satellite observing systems since experience with sounder data has shown that improvements in forecasts due to satellite-derived information is due less to a general error reduction than to the ability to fill data-sparse regions. The reported study concentrates on the evaluation of the observing system simulation experimental design and on the assessment of the potential of remotely sensed marine surface wind data.

  12. Assessment of Wind Parameter Sensitivity on Extreme and Fatigue Wind Turbine Loads

    Energy Technology Data Exchange (ETDEWEB)

    Robertson, Amy N [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Sethuraman, Latha [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Jonkman, Jason [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Quick, Julian [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2018-01-12

    Wind turbines are designed using a set of simulations to ascertain the structural loads that the turbine could encounter. While mean hub-height wind speed is considered to vary, other wind parameters such as turbulence spectra, sheer, veer, spatial coherence, and component correlation are fixed or conditional values that, in reality, could have different characteristics at different sites and have a significant effect on the resulting loads. This paper therefore seeks to assess the sensitivity of different wind parameters on the resulting ultimate and fatigue loads on the turbine during normal operational conditions. Eighteen different wind parameters are screened using an Elementary Effects approach with radial points. As expected, the results show a high sensitivity of the loads to the turbulence standard deviation in the primary wind direction, but the sensitivity to wind shear is often much greater. To a lesser extent, other wind parameters that drive loads include the coherence in the primary wind direction and veer.

  13. Assessment of Wind Parameter Sensitivity on Ultimate and Fatigue Wind Turbine Loads: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Robertson, Amy N [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Sethuraman, Latha [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Jonkman, Jason [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Quick, Julian [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2018-02-13

    Wind turbines are designed using a set of simulations to ascertain the structural loads that the turbine could encounter. While mean hub-height wind speed is considered to vary, other wind parameters such as turbulence spectra, sheer, veer, spatial coherence, and component correlation are fixed or conditional values that, in reality, could have different characteristics at different sites and have a significant effect on the resulting loads. This paper therefore seeks to assess the sensitivity of different wind parameters on the resulting ultimate and fatigue loads on the turbine during normal operational conditions. Eighteen different wind parameters are screened using an Elementary Effects approach with radial points. As expected, the results show a high sensitivity of the loads to the turbulence standard deviation in the primary wind direction, but the sensitivity to wind shear is often much greater. To a lesser extent, other wind parameters that drive loads include the coherence in the primary wind direction and veer.

  14. Fatigue Load Sensitivity Based Optimal Active Power Dispatch For Wind Farms

    DEFF Research Database (Denmark)

    Zhao, Haoran; Wu, Qiuwei; Huang, Shaojun

    2017-01-01

    This paper proposes an optimal active power dispatch algorithm for wind farms based on Wind Turbine (WT) load sensitivity. The control objectives include tracking power references from the system operator and minimizing fatigue loads experienced by WTs. The sensitivity of WT fatigue loads to power...... sensitivity are derived, which significantly improves the computation efficiency of the local WT controller. The proposed algorithm can be implemented in different active power control schemes. Case studies were conducted with a wind farm under balance control for both low and high wind conditions...

  15. Annual mean sea level and its sensitivity to wind climate

    Science.gov (United States)

    Gerkema, Theo; Duran Matute, Matias

    2017-04-01

    the west-east component of the net wind energy vector, with some further improvement if one also includes the south-north component and annual mean atmospheric pressure. Knowledge of these local correlations can then be used to correct values of annual mean sea for these atmospheric effects. This halves the margin of error (expressed as 95%-confidence interval) for linear trends in a 20-year sea level record. The sensitivity on wind direction has a regional variability, even on a small scale like the Dutch Wadden Sea. Model results illustrate the detailed spatial patterns in inter-annual variability of annual mean sea level. This study also implies that climatic changes in wind direction, or in the strength of winds from a specific direction, may affect local annual mean sea level quite significantly.

  16. CAT LIDAR wind shear studies

    Science.gov (United States)

    Goff, R. W.

    1978-01-01

    The studies considered the major meteorological factors producing wind shear, methods to define and classify wind shear in terms significant from an aircraft perturbation standpoint, the significance of sensor location and scan geometry on the detection and measurement of wind shear, and the tradeoffs involved in sensor performance such as range/velocity resolution, update frequency and data averaging interval.

  17. Wind Farm Group Efficiency - A Sensitivity Analysis with a Mesoscale Model

    DEFF Research Database (Denmark)

    Volker, Patrick; Badger, Jake; Hahmann, Andrea N.

    2014-01-01

    In the North Sea the total installed capacity was in 2012 5GW, and it estimated that it will grow to 40GW by 2020 (EWEA). This will lead to an increasing wind farm density in regions with the most favourable conditions. In this study, we investigate the sensitivity of power density losses to wind...

  18. Wind farm radar study

    International Nuclear Information System (INIS)

    Davies, N.G.

    1995-01-01

    This report examines the possible degradations of radar performance that may be caused by the presence of a wind turbine generator within the radar coverage area. A brief literature survey reviews the previously published work, which is mainly concerned with degradation of broadcast TV reception. Estimates are made of wind turbine generator scattering cross-sections, and of the time and Doppler characteristics of the echo signals from representative wind turbine generator. The general characteristics of radar detection and tracking methods are described, and the behaviour of such systems in the presence of strong returns from a wind turbine generator (or an array of them) is discussed. (author)

  19. Roughness Sensitivity Comparisons of Wind Turbine Blade Sections

    Energy Technology Data Exchange (ETDEWEB)

    Wilcox, Benjamin J. [Texas A & M Univ., College Station, TX (United States). Dept. of Aerospace Engineering; White, Edward B. [Texas A & M Univ., College Station, TX (United States). Dept. of Aerospace Engineering; Maniaci, David Charles [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Wind Energy Technologies Dept.

    2017-10-01

    One explanation for wind turbine power degradation is insect roughness. Historical studies on insect-induced power degradation have used simulation methods which are either un- representative of actual insect roughness or too costly or time-consuming to be applied to wide-scale testing. Furthermore, the role of airfoil geometry in determining the relations between insect impingement locations and roughness sensitivity has not been studied. To link the effects of airfoil geometry, insect impingement locations, and roughness sensitivity, a simulation code was written to determine representative insect collection patterns for different airfoil shapes. Insect collection pattern data was then used to simulate roughness on an NREL S814 airfoil that was tested in a wind tunnel at Reynolds numbers between 1.6 x 106 and 4.0 x 106. Results are compared to previous tests of a NACA 633 -418 airfoil. Increasing roughness height and density results in decreased maximum lift, lift curve slope, and lift-to-drag ratio. Increasing roughness height, density, or Reynolds number results in earlier bypass transition, with critical roughness Reynolds numbers lying within the historical range. Increased roughness sensitivity on the 25% thick NREL S814 is observed compared to the 18% thick NACA 63 3 -418. Blade-element-momentum analysis was used to calculate annual energy production losses of 4.9% and 6.8% for a NACA 633 -418 turbine and an NREL S814 turbine, respectively, operating with 200 μm roughness. These compare well to historical field measurements.

  20. Dynamic Resonance Sensitivity Analysis in Wind Farms

    DEFF Research Database (Denmark)

    Ebrahimzadeh, Esmaeil; Blaabjerg, Frede; Wang, Xiongfei

    2017-01-01

    (PFs) are calculated by critical eigenvalue sensitivity analysis versus the entries of the MIMO matrix. The PF analysis locates the most exciting bus of the resonances, where can be the best location to install the passive or active filters to reduce the harmonic resonance problems. Time...

  1. Wind climate estimation using WRF model output: method and model sensitivities over the sea

    DEFF Research Database (Denmark)

    Hahmann, Andrea N.; Vincent, Claire Louise; Peña, Alfredo

    2015-01-01

    setup parameters. The results of the year-long sensitivity simulations show that the long-term mean wind speed simulated by the WRF model offshore in the region studied is quite insensitive to the global reanalysis, the number of vertical levels, and the horizontal resolution of the sea surface...... temperature used as lower boundary conditions. Also, the strength and form (grid vs spectral) of the nudging is quite irrelevant for the mean wind speed at 100 m. Large sensitivity is found to the choice of boundary layer parametrization, and to the length of the period that is discarded as spin-up to produce...... a wind climatology. It is found that the spin-up period for the boundary layer winds is likely larger than 12 h over land and could affect the wind climatology for points offshore for quite a distance downstream from the coast....

  2. Calculating the sensitivity of wind turbine loads to wind inputs using response surfaces

    International Nuclear Information System (INIS)

    Rinker, Jennifer M.

    2016-01-01

    This paper presents a methodology to calculate wind turbine load sensitivities to turbulence parameters through the use of response surfaces. A response surface is a highdimensional polynomial surface that can be calibrated to any set of input/output data and then used to generate synthetic data at a low computational cost. Sobol sensitivity indices (SIs) can then be calculated with relative ease using the calibrated response surface. The proposed methodology is demonstrated by calculating the total sensitivity of the maximum blade root bending moment of the WindPACT 5 MW reference model to four turbulence input parameters: a reference mean wind speed, a reference turbulence intensity, the Kaimal length scale, and a novel parameter reflecting the nonstationarity present in the inflow turbulence. The input/output data used to calibrate the response surface were generated for a previous project. The fit of the calibrated response surface is evaluated in terms of error between the model and the training data and in terms of the convergence. The Sobol SIs are calculated using the calibrated response surface, and the convergence is examined. The Sobol SIs reveal that, of the four turbulence parameters examined in this paper, the variance caused by the Kaimal length scale and nonstationarity parameter are negligible. Thus, the findings in this paper represent the first systematic evidence that stochastic wind turbine load response statistics can be modeled purely by mean wind wind speed and turbulence intensity. (paper)

  3. Calculating the sensitivity of wind turbine loads to wind inputs using response surfaces

    DEFF Research Database (Denmark)

    Rinker, Jennifer M.

    2016-01-01

    at a low computational cost. Sobol sensitivity indices (SIs) can then be calculated with relative ease using the calibrated response surface. The proposed methodology is demonstrated by calculating the total sensitivity of the maximum blade root bending moment of the WindPACT 5 MW reference model to four......This paper presents a methodology to calculate wind turbine load sensitivities to turbulence parameters through the use of response surfaces. A response surface is a high-dimensional polynomial surface that can be calibrated to any set of input/output data and then used to generate synthetic data...... turbulence input parameters: a reference mean wind speed, a reference turbulence intensity, the Kaimal length scale, and a novel parameter reflecting the nonstationarity present in the inflow turbulence. The input/output data used to calibrate the response surface were generated for a previous project...

  4. Sensitivity analysis of nacelle lidar free stream wind speed measurements to wind-induction reconstruction model and lidar range configuration

    DEFF Research Database (Denmark)

    Svensson, Elin; Borraccino, Antoine; Meyer Forsting, Alexander Raul

    The sensitivity of nacelle lidar wind speed measurements to wind-induction models and lidar range configurations is studied using experimental data from the Nørrekær Enge (NKE) measurement campaign and simulated lidar data from Reynold-Averaged Navier Stokes (RANS) aerodynamic computational fluid...... the ZDM was configured to measure at five distances. From the configured distances, a large number of range configurations were created and systematically tested to determine the sensitivity of the reconstructed wind speeds to the number of ranges, minimum range and maximum range in the range......) of the fitting residuals. The results demonstrate that it is not possible to use RANS CFD simulated lidar data to determine optimal range configurations for real-time nacelle lidars due to their perfect (unrealistic) representation of the simulated flow field. The recommended range configurations are therefore...

  5. Sensitivity of a numerical wave model on wind re-analysis datasets

    Science.gov (United States)

    Lavidas, George; Venugopal, Vengatesan; Friedrich, Daniel

    2017-03-01

    Wind is the dominant process for wave generation. Detailed evaluation of metocean conditions strengthens our understanding of issues concerning potential offshore applications. However, the scarcity of buoys and high cost of monitoring systems pose a barrier to properly defining offshore conditions. Through use of numerical wave models, metocean conditions can be hindcasted and forecasted providing reliable characterisations. This study reports the sensitivity of wind inputs on a numerical wave model for the Scottish region. Two re-analysis wind datasets with different spatio-temporal characteristics are used, the ERA-Interim Re-Analysis and the CFSR-NCEP Re-Analysis dataset. Different wind products alter results, affecting the accuracy obtained. The scope of this study is to assess different available wind databases and provide information concerning the most appropriate wind dataset for the specific region, based on temporal, spatial and geographic terms for wave modelling and offshore applications. Both wind input datasets delivered results from the numerical wave model with good correlation. Wave results by the 1-h dataset have higher peaks and lower biases, in expense of a high scatter index. On the other hand, the 6-h dataset has lower scatter but higher biases. The study shows how wind dataset affects the numerical wave modelling performance, and that depending on location and study needs, different wind inputs should be considered.

  6. Applying value sensitive design (VSD) to wind turbines and wind parks: an exploration.

    Science.gov (United States)

    Oosterlaken, Ilse

    2015-04-01

    Community acceptance still remains a challenge for wind energy projects. The most popular explanation for local opposition, the Not in My Backyard effect, has received fierce criticism in the past decade. Critics argue that opposition is not merely a matter of selfishness or ignorance, but that moral, ecological and aesthetic values play an important role. In order to better take such values into account, a more bottom-up, participatory decision process is usually proposed. Research on this topic focusses on either stakeholder motivations/attitudes, or their behavior during project implementation. This paper proposes a third research focus, namely the 'objects' which elicit certain behavioral responses and attitudes-the wind turbine and parks. More concretely, this paper explores Value Sensitive Design (VSD) as way to arrive at wind turbines and parks that better embed or reflect key values. After a critical discussion of the notion of acceptance versus acceptability and support, the paper discusses existing literature on ecology and aesthetics in relation to wind turbine/park design, which could serve as 'building blocks' of a more integral VSD approach of the topic. It also discusses the challenge of demarcating wind park projects as VSD projects. A further challenge is that VSD has been applied mainly at the level of technical artifacts, whereas wind parks can best be conceptualized as socio-technical system. This new application would therefore expand the current practice of VSD, and may as a consequence also lead to interesting new insights for the VSD community. The paper concludes that such an outcome-oriented approach of wind turbines and park is worth exploring further, as a supplement to rather than a replacement of the process-oriented approach that is promoted by the current literature on community acceptance of wind parks.

  7. Integration of wind power in the Danish generation system. EC wind power penetration study, phase 2

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1989-06-01

    The Commission of the European Communities has asked utilities in the member countries to carry out a coordinated study of the wind energy potential. The main objective is to show the consequences for the future electricity system when integrating wind power production covering 5, 10 or 15% of total demand. In addition to the best estimate scenario believed to be operational, some additional calculations have been carried out: wind power production as a negative load only (not operational for the total system); different levels of investment in wind farms. The methodology is based on the following steps: define a reference scenario for year 2000; define an alternative scenario with a certain amount of wind power production; calculate time-series for electrical load and district heating from combined heat/power production; calculate time-series for wind power production; make economic evaluation and sensitivity analysis; show environmental differences. Incorporation of wind power into the ELSAM power system, with the wind energy meeting, about 5% of demand will give rise to additional control capacity, or call for new contracts with neighbouring countries. The study includes estimated network investments. The simulations have been made with the SIM and SLUMP computer programmes. The economic analyses and the sensitivity analyses have been carried out using spreadsheets. The conclusion concerning profitability - based on the best estimate assumptions - is that the studied wind power scenarios are unprofitable. (EG)

  8. Numeric-modeling sensitivity analysis of the performance of wind turbine arrays

    Energy Technology Data Exchange (ETDEWEB)

    Lissaman, P.B.S.; Gyatt, G.W.; Zalay, A.D.

    1982-06-01

    An evaluation of the numerical model created by Lissaman for predicting the performance of wind turbine arrays has been made. Model predictions of the wake parameters have been compared with both full-scale and wind tunnel measurements. Only limited, full-scale data were available, while wind tunnel studies showed difficulties in representing real meteorological conditions. Nevertheless, several modifications and additions have been made to the model using both theoretical and empirical techniques and the new model shows good correlation with experiment. The larger wake growth rate and shorter near wake length predicted by the new model lead to reduced interference effects on downstream turbines and hence greater array efficiencies. The array model has also been re-examined and now incorporates the ability to show the effects of real meteorological conditions such as variations in wind speed and unsteady winds. The resulting computer code has been run to show the sensitivity of array performance to meteorological, machine, and array parameters. Ambient turbulence and windwise spacing are shown to dominate, while hub height ratio is seen to be relatively unimportant. Finally, a detailed analysis of the Goodnoe Hills wind farm in Washington has been made to show how power output can be expected to vary with ambient turbulence, wind speed, and wind direction.

  9. Advancements in Wind Integration Study Data Modeling: The Wind Integration National Dataset (WIND) Toolkit; Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Draxl, C.; Hodge, B. M.; Orwig, K.; Jones, W.; Searight, K.; Getman, D.; Harrold, S.; McCaa, J.; Cline, J.; Clark, C.

    2013-10-01

    Regional wind integration studies in the United States require detailed wind power output data at many locations to perform simulations of how the power system will operate under high-penetration scenarios. The wind data sets that serve as inputs into the study must realistically reflect the ramping characteristics, spatial and temporal correlations, and capacity factors of the simulated wind plants, as well as be time synchronized with available load profiles. The Wind Integration National Dataset (WIND) Toolkit described in this paper fulfills these requirements. A wind resource dataset, wind power production time series, and simulated forecasts from a numerical weather prediction model run on a nationwide 2-km grid at 5-min resolution will be made publicly available for more than 110,000 onshore and offshore wind power production sites.

  10. Airfoil data sensitivity analysis for actuator disc simulations used in wind turbine applications

    DEFF Research Database (Denmark)

    Nilsson, Karl; Breton, Simon-Philippe; Sørensen, Jens Nørkær

    2014-01-01

    To analyse the sensitivity of blade geometry and airfoil characteristics on the prediction of performance characteristics of wind farms, large-eddy simulations using an actuator disc (ACD) method are performed for three different blade/airfoil configurations. The aim of the study is to determine ...

  11. Corollary discharge inhibition of wind-sensitive cercal giant interneurons in the singing field cricket

    Science.gov (United States)

    Hedwig, Berthold

    2014-01-01

    Crickets carry wind-sensitive mechanoreceptors on their cerci, which, in response to the airflow produced by approaching predators, triggers escape reactions via ascending giant interneurons (GIs). Males also activate their cercal system by air currents generated due to the wing movements underlying sound production. Singing males still respond to external wind stimulation, but are not startled by the self-generated airflow. To investigate how the nervous system discriminates sensory responses to self-generated and external airflow, we intracellularly recorded wind-sensitive afferents and ventral GIs of the cercal escape pathway in fictively singing crickets, a situation lacking any self-stimulation. GI spiking was reduced whenever cercal wind stimulation coincided with singing motor activity. The axonal terminals of cercal afferents showed no indication of presynaptic inhibition during singing. In two ventral GIs, however, a corollary discharge inhibition occurred strictly in phase with the singing motor pattern. Paired intracellular recordings revealed that this inhibition was not mediated by the activity of the previously identified corollary discharge interneuron (CDI) that rhythmically inhibits the auditory pathway during singing. Cercal wind stimulation, however, reduced the spike activity of this CDI by postsynaptic inhibition. Our study reveals how precisely timed corollary discharge inhibition of ventral GIs can prevent self-generated airflow from triggering inadvertent escape responses in singing crickets. The results indicate that the responsiveness of the auditory and wind-sensitive pathway is modulated by distinct CDIs in singing crickets and that the corollary discharge inhibition in the auditory pathway can be attenuated by cercal wind stimulation. PMID:25318763

  12. Global Sensitivity Analysis of High Speed Shaft Subsystem of a Wind Turbine Drive Train

    Directory of Open Access Journals (Sweden)

    Saeed Asadi

    2018-01-01

    Full Text Available The wind turbine dynamics are complex and critical area of study for the wind industry. Quantification of the effective factors to wind turbine performance is valuable for making improvements to both power performance and turbine health. In this paper, the global sensitivity analysis of validated mathematical model for high speed shaft drive train test rig has been developed in order to evaluate the contribution of systems input parameters to the specified objective functions. The drive train in this study consists of a 3-phase induction motor, flexible shafts, shafts’ coupling, bearing housing, and disk with an eccentric mass. The governing equations were derived by using the Lagrangian formalism and were solved numerically by Newmark method. The variance based global sensitivity indices are introduced to evaluate the contribution of input structural parameters correlated to the objective functions. The conclusion from the current research provides informative beneficial data in terms of design and optimization of a drive train setup and also can provide better understanding of wind turbine drive train system dynamics with respect to different structural parameters, ultimately designing more efficient drive trains. Finally, the proposed global sensitivity analysis (GSA methodology demonstrates the detectability of faults in different components.

  13. Wind energy systems information user study

    Energy Technology Data Exchange (ETDEWEB)

    Belew, W.W.; Wood, B.L.; Marle, T.L.; Reinhardt, C.L.

    1981-01-01

    This report describes the results of a series of telephone interviews with potential users of information on wind energy conversion. These interviews, part of a larger study covering nine different solar technologies, attempted to identify: the type of information each distinctive group of information users needed, and the best way of getting information to that group. Groups studied include: wind energy conversion system researchers; wind energy conversion system manufacturer representatives; wind energy conversion system distributors; wind turbine engineers; utility representatives; educators; county agents and extension service agents; and wind turbine owners.

  14. Reminiscences on the study of wind waves

    Science.gov (United States)

    MITSUYASU, Hisashi

    2015-01-01

    The wind blowing over sea surface generates tiny wind waves. They develop with time and space absorbing wind energy, and become huge wind waves usually referred to ocean surface waves. The wind waves cause not only serious sea disasters but also take important roles in the local and global climate changes by affecting the fluxes of momentum, heat and gases (e.g. CO2) through the air-sea boundary. The present paper reviews the selected studies on wind waves conducted by our group in the Research Institute for Applied Mechanics (RIAM), Kyushu University. The themes discussed are interactions between water waves and winds, the energy spectrum of wind waves, nonlinear properties of wind waves, and the effects of surfactant on some air-sea interaction phenomena. PMID:25864467

  15. Wind Generation Feasibility Study in Bethel, AK

    Energy Technology Data Exchange (ETDEWEB)

    Tom Humphrey, YKHC; Lance Kincaid, EMCOR Energy & Technologies

    2004-07-31

    This report studies the wind resources in the Yukon-Kuskokwim Health Corporation (YKHC) region, located in southwestern Alaska, and the applicability of wind generation technologies to YKHC facilities.

  16. Wind energy market study Eastern Europe. Poland

    International Nuclear Information System (INIS)

    Skjerk Christensen, P.

    1994-04-01

    The main objective of the THERMIE Associated Measure WE05 is to study market conditions and estimate the market for wind power in Eastern Europe. This report describes the results of a study of the conditions in Poland, which has been concentrated on the following areas: wind energy potential in Poland; data concerning the present structure of the power production system including costs; payback prices, subsidies, etc. with relation to renewable energy sources, especially wind power; information on existing wine turbines and their production in Poland; possibilities for co-production of wind turbines by Polish and EC factories, and rules and legislation pertaining to the establishment of wind turbines and to power production by wind, eg regulations related to grid connection, safety and environment. According to existing data there are possibilities for using the wind potential in certain parts of poland. The wind data have to be improved if particular sites are considered for wind parks. The current official plans concerning the energy system have taken renewable sources into consideration, including wind power that is estimated to contribute ∼ 1 GWh by 2005-2010. Wind turbines may be connected to the public grid with due regard to the strength of the line. Presently, the owner has to pay all the costs, however, new rules are under consideration. The conditions for the connection and operation of wind turbines have to be discussed with the particular utility on an an-hoc basis. (EG)

  17. A tall tower study of Missouri winds

    Energy Technology Data Exchange (ETDEWEB)

    Fox, Neil I. [Department of Soil, Environmental and Atmospheric Sciences, 332 ABNR Building, University of Missouri, Columbia, MO 65211 (United States)

    2011-01-15

    This paper summarizes the results of a study of wind speeds observed at heights up to 150 m above ground level around Missouri. This is an amalgamation of four projects that allowed a total of eleven tall communication towers to be instrumented with wind observation equipment across the State of Missouri. This provided an assessment of the wind resource and the characteristics of the seasonal and diurnal cycles of wind in different areas of Missouri at the heights of utility scale wind turbines. Comparisons were also made to wind speeds predicted at these levels from a previously published wind map. The main finding was that the observed winds at each tower were smaller than those presented in the wind map. The discrepancy is most likely to be due to underestimation of the surface roughness and turbulence leading to an overestimation of near-surface wind shear. However, the wind shear, as expressed by the shear parameter was consistently greater than the 'standard' value of 1.4. The reconciliation of these two apparently contradictory findings is that the shear varies with the height at which it is measured. In wind resource assessment, wind shear is usually observed below 50 m and is tacitly assumed to be constant with height when used to extrapolate winds to higher levels. The author advocates the use of the friction velocity as a measure of shear in wind power applications in preference to the shear parameter that is usually used. This is because the shear parameter has a velocity bias that can also manifest as a bias with height or season. As wind power resource assessment is starting to use taller towers than the standard 50 m, intercomparison of site resources and extrapolation to turbine heights can be compromised if the shear parameter is used. (author)

  18. Multi-Response Parameter Interval Sensitivity and Optimization for the Composite Tape Winding Process

    Science.gov (United States)

    Yu, Tao; Kang, Chao; Zhao, Pan

    2018-01-01

    The composite tape winding process, which utilizes a tape winding machine and prepreg tapes, provides a promising way to improve the quality of composite products. Nevertheless, the process parameters of composite tape winding have crucial effects on the tensile strength and void content, which are closely related to the performances of the winding products. In this article, two different object values of winding products, including mechanical performance (tensile strength) and a physical property (void content), were respectively calculated. Thereafter, the paper presents an integrated methodology by combining multi-parameter relative sensitivity analysis and single-parameter sensitivity analysis to obtain the optimal intervals of the composite tape winding process. First, the global multi-parameter sensitivity analysis method was applied to investigate the sensitivity of each parameter in the tape winding processing. Then, the local single-parameter sensitivity analysis method was employed to calculate the sensitivity of a single parameter within the corresponding range. Finally, the stability and instability ranges of each parameter were distinguished. Meanwhile, the authors optimized the process parameter ranges and provided comprehensive optimized intervals of the winding parameters. The verification test validated that the optimized intervals of the process parameters were reliable and stable for winding products manufacturing. PMID:29385048

  19. Repowering of wind farms - A case study

    Energy Technology Data Exchange (ETDEWEB)

    Nivedh, B.S. [Quality Engineering and Software Technologies, Bangalore (India); Devi, R.P.K. [College of Engineering. Power Systems Engineering, Guindy (India); Sreevalsan, E. [Gamesa Wind Turbines India Private Limited, Chennai (India)

    2012-07-01

    The main objective of the study is to devise a method for assessing the repowering potential and to improve the energy output from the wind farms and also to understand the impact on the power quality due to repowering. With repowering, the first-generation wind turbines can be replaced with modern multi-megawatt wind turbines. To carry-out the study an old wind farm located at Kayathar, Tamilnadu is selected. The wind farm was commissioned in 1990's with a capacity of 7.35MW, which consists of 36 Wind Turbines each with the capacity of 200kW and 225kW. The present annual energy generation of the wind farm is 7350MWhr with the plant load factor of 11.41%. The intent of this study is to predict the annual energy output of the wind farm after the repowering using WAsP (Wind Atlas Analysis Application Program). Further this study analyses the power quality issues of the various Wind Turbines. In addition, the main feeder, in which the wind farm which is taken for the study also modeled and the impact on power quality due to repowering also studied. Simulations were carried out using MATLAB. The results are analyzed to understand the significance of repowering to overcome the energy crisis of the nation since the best locations for wind in India are occupied by old wind turbines. The following are the observations and conclusions from the above study. Plant load factor (PLF) increased to 24 %, Energy yield increased to more than 4 times and the capacity of the wind farm became double. And in the view of power quality, comparing to the existing Feeder, Repowered Feeder having less reactive power consumption, voltage variations and flickers except the harmonic distortion. (Author)

  20. 2D Numerical Simulation and Sensitive Analysis of H-Darrieus Wind Turbine

    Directory of Open Access Journals (Sweden)

    Seyed Mohammad E. Saryazdi

    2018-02-01

    Full Text Available Recently, a lot of attention has been devoted to the use of Darrieus wind turbines in urban areas. The aerodynamics of a Darrieus turbine are very complex due to dynamic stall and changing forces on the turbine triggered by changing horizontal angles. In this study, the aerodynamics of H-rotor vertical axis wind turbine (VAWT has been studied using computational fluid dynamics via two different turbulence models. Shear stress transport (SST k-ω turbulence model was used to simulate a 2D unsteady model of the H-Darrieus turbine. In order to complete this simulation, sensitivity analysis of the effective turbine parameters such as solidity factor, airfoil shape, wind velocity and shaft diameter were done. To simulate the flow through the turbine, a 2D simplified computational domain has been generated. Then fine mesh for each case consisting of different turbulence models and dimensions has been generated. Each mesh in this simulation dependent on effective parameters consisted of domain size, mesh quality, time step and total revolution. The sliding mesh method was applied to evaluate the unsteady interaction between the stationary and rotating components. Previous works just simulated turbine, while in our study sensitivity analysis of effective parameters was done. The simulation results closely match the experimental data, providing an efficient and reliable foundation to study wind turbine aerodynamics. This also demonstrates computing the best value of the effective parameter. The sensitivity analysis revealed best value of the effective parameter that could be used in the process of designing turbine. This work provides the first step in developing an accurate 3D aerodynamic modeling of Darrieus wind turbines. Article History: Received :August 19th 2017; Received: December 15th 2017; Accepted: Januari 14th 2018; Available online How to Cite This Article: Saryazdi, S. M. E. and Boroushaki, M. (2018 2D Numerical Simulation and Sensitive

  1. National Offshore Wind Energy Grid Interconnection Study

    Energy Technology Data Exchange (ETDEWEB)

    Daniel, John P. [ABB Inc; Liu, Shu [ABB Inc; Ibanez, Eduardo [National Renewable Energy Laboratory; Pennock, Ken [AWS Truepower; Reed, Greg [University of Pittsburgh; Hanes, Spencer [Duke Energy

    2014-07-30

    The National Offshore Wind Energy Grid Interconnection Study (NOWEGIS) considers the availability and potential impacts of interconnecting large amounts of offshore wind energy into the transmission system of the lower 48 contiguous United States. A total of 54GW of offshore wind was assumed to be the target for the analyses conducted. A variety of issues are considered including: the anticipated staging of offshore wind; the offshore wind resource availability; offshore wind energy power production profiles; offshore wind variability; present and potential technologies for collection and delivery of offshore wind energy to the onshore grid; potential impacts to existing utility systems most likely to receive large amounts of offshore wind; and regulatory influences on offshore wind development. The technologies considered the reliability of various high-voltage ac (HVAC) and high-voltage dc (HVDC) technology options and configurations. The utility system impacts of GW-scale integration of offshore wind are considered from an operational steady-state perspective and from a regional and national production cost perspective.

  2. Moroccan wind farm potential feasibility. Case study

    International Nuclear Information System (INIS)

    Nouri, Abdellatif; Ait Babram, Mohamed; Elwarraki, Elmostafa; Enzili, Mustapha

    2016-01-01

    Highlights: • A new methodology for the technical feasibility of wind farm potentials is proposed. • The wind resources of two different sites in Morocco are compared. • Comparison between short and long term data using multivariate analysis is made. • Geographic information system implementation. • A 10 MW wind farm is designed and optimized. - Abstract: The subject of this paper is the elaboration of a methodology to study the technical feasibility of a wind farm potential. The implementation of this methodology allows a comparison between the wind resources of two different sites in Morocco. One site is located in the region of Essaouira, whereas the other one is located in the region of Safi. The comparison is based on real wind data collected from two masts at the heights of 30, 50, and 60 m. Each of the masts is installed at one of the mentioned potential sites over a fixed time period, lasting fifteen months for the first site, and eight months for the second one. The aim is the determination of the most applicable site presenting a good potential for a statistical study in order to predict long-term wind behaviors. Thus, the geographical situation study of the chosen site including topography, roughness and obstacles, is carried out. Furthermore, the wind resource using data, generated by the measuring masts, is evaluated. Finally, the areas which present great wind potential are located and the wind farm turbine locations are optimized by using the WAsP software.

  3. Wind-Battery-Hydrogen Integration Study

    Energy Technology Data Exchange (ETDEWEB)

    Fingersh, L. J.

    2004-05-01

    A study was performed to examine the possibility of using batteries and Hydrogen systems to add dispatchability to wind power. A second study examined the production of hydrogen by wind power for sale into a fuels market. Calendar year 2002 load information from the California ISO was combined with 2002 generated wind power from the Lake Benton wind farm in Minnesota. Control systems were developed and optimized, and grid operation for 2002 was simulated with batteries, electrolyzers, fuel cells or other elements. This report presents the results of the two studies.

  4. Configuration study of large wind parks

    Energy Technology Data Exchange (ETDEWEB)

    Lundberg, Stefan

    2003-07-01

    In this thesis, layouts of various large-scale wind parks, using both AC as well as DC, are investigated. Loss modelling of the wind park components as well as calculations of the energy capture of the turbines using various electrical systems are performed, and the energy production cost of the various park configurations is determined. The most interesting candidate for a DC transmission based wind park was investigated more in detail, the series DC wind park. Finally, the power quality impact in the PCC (point of common coupling) was studied. It was found that from an energy capture point of view, the difference in energy production between various wind turbine systems is very small. Of all the investigated wind park configurations, the wind park with the series connected DC wind turbines seems to have the best potential to give the lowest energy production cost, if the transmission distance is longer then 10-20 km. Regarding the series DC wind park it was found that it is the most difficult one to control. However, a control algorithm for the series park and its turbines was derived and successfully tested. Still, several more details regarding the control of the series wind park has to be dealt with.

  5. Sensitivity of Risk-Based Maintenance Planning of Offshore Wind Turbine Farms

    DEFF Research Database (Denmark)

    Ambühl, Simon; Sørensen, John Dalsgaard

    2017-01-01

    Inspection and maintenance expenses cover a considerable part of the cost of energy from offshore wind turbines. Risk-based maintenance planning approaches are a powerful tool to optimize maintenance and inspection actions and decrease the total maintenance expenses. Risk-based planning is based...... on many input parameters, which are in reality often not completely known. This paper will assess the cost impact of this incomplete knowledge based on a case study following risk-based maintenance planning. The sensitivity study focuses on weather forecast uncertainties, incomplete knowledge about...... the needed repair time on the site as well as uncertainties about the operational range of the boat and helicopter used to access the broken wind turbine. The cost saving potential is estimated by running Crude Monte Carlo simulations. Furthermore, corrective and preventive (scheduled and condition...

  6. Sault Tribe Wind Energy Feasibility Study

    Energy Technology Data Exchange (ETDEWEB)

    Toni Osterhout; Global Energy Concepts

    2005-07-31

    The Sault Tribe conducted a feasibility study on tribal lands in the Upper Peninsula of Michigan to determine the technical and economic feasibility of both small and large-scale wind power development on tribal lands. The study included a wind resource assessment, transmission system analysis, engineering and regulatory analyzes and assessments.

  7. Aleutian Pribilof Islands Wind Energy Feasibility Study

    Energy Technology Data Exchange (ETDEWEB)

    Bruce A. Wright

    2012-03-27

    Under this project, the Aleutian Pribilof Islands Association (APIA) conducted wind feasibility studies for Adak, False Pass, Nikolski, Sand Point and St. George. The DOE funds were also be used to continue APIA's role as project coordinator, to expand the communication network quality between all participants and with other wind interest groups in the state and to provide continued education and training opportunities for regional participants. This DOE project began 09/01/2005. We completed the economic and technical feasibility studies for Adak. These were funded by the Alaska Energy Authority. Both wind and hydro appear to be viable renewable energy options for Adak. In False Pass the wind resource is generally good but the site has high turbulence. This would require special care with turbine selection and operations. False Pass may be more suitable for a tidal project. APIA is funded to complete a False Pass tidal feasibility study in 2012. Nikolski has superb potential for wind power development with Class 7 wind power density, moderate wind shear, bi-directional winds and low turbulence. APIA secured nearly $1M from the United States Department of Agriculture Rural Utilities Service Assistance to Rural Communities with Extremely High Energy Costs to install a 65kW wind turbine. The measured average power density and wind speed at Sand Point measured at 20m (66ft), are 424 W/m2 and 6.7 m/s (14.9 mph) respectively. Two 500kW Vestas turbines were installed and when fully integrated in 2012 are expected to provide a cost effective and clean source of electricity, reduce overall diesel fuel consumption estimated at 130,000 gallons/year and decrease air emissions associated with the consumption of diesel fuel. St. George Island has a Class 7 wind resource, which is superior for wind power development. The current strategy, led by Alaska Energy Authority, is to upgrade the St. George electrical distribution system and power plant. Avian studies in Nikolski

  8. Applying Value Sensitive Design (VSD) to Wind Turbines and Wind Parks : An Exploration

    NARCIS (Netherlands)

    Oosterlaken, E.T.

    2014-01-01

    Community acceptance still remains a challenge for wind energy projects. The most popular explanation for local opposition, the Not in My Backyard effect, has received fierce criticism in the past decade. Critics argue that opposition is not merely a matter of selfishness or ignorance, but that

  9. Oscillatory Stability and Eigenvalue Sensitivity Analysis of A DFIG Wind Turbine System

    DEFF Research Database (Denmark)

    Yang, Lihui; Xu, Zhao; Østergaard, Jacob

    2011-01-01

    This paper focuses on modeling and oscillatory stability analysis of a wind turbine with doubly fed induction generator (DFIG). A detailed mathematical model of DFIG wind turbine with vector-control loops is developed, based on which the loci of the system Jacobian's eigenvalues have been analyzed......, showing that, without appropriate controller tuning a Hopf bifurcation can occur in such a system due to various factors, such as wind speed. Subsequently, eigenvalue sensitivity with respect to machine and control parameters is performed to assess their impacts on system stability. Moreover, the Hopf...

  10. LCA sensitivity analysis of a multi-megawatt wind turbine

    International Nuclear Information System (INIS)

    Martinez, E.; Jimenez, E.; Blanco, J.; Sanz, F.

    2010-01-01

    During recent years renewables have been acquiring gradually a significant importance in the world market (especially in the Spanish energetic market) and in society; this fact makes clear the need to increase and improve knowledge of these power sources. Starting from the results of a Life Cycle Assessment (LCA) of a multi-megawatt wind turbine, this work is aimed to assess the relevance of different choices that have been made during its development. Looking always to cover the largest possible spectrum of options, four scenarios have been analysed, focused on four main phases of lifecycle: maintenance, manufacturing, dismantling, and recycling. These scenarios facilitate to assess the degree of uncertainty of the developed LCA due to choices made, excluding from the assessment the uncertainty due to the inaccuracy and the simplification of the environmental models used or spatial and temporal variability in different parameters. The work has been developed at all times using the of Eco-indicator99 LCA method. (author)

  11. LCA sensitivity analysis of a multi-megawatt wind turbine

    Energy Technology Data Exchange (ETDEWEB)

    Martinez, E. [Grupo Eolicas Riojanas, Carretera de Laguardia, 91-93, 26006 Logrono, La Rioja (Spain); Department of Mechanical Engineering, University of La Rioja, Logrono, La Rioja (Spain); Jimenez, E. [Department of Electrical Engineering, University of La Rioja, Logrono, La Rioja (Spain); Blanco, J.; Sanz, F. [Department of Mechanical Engineering, University of La Rioja, Logrono, La Rioja (Spain)

    2010-07-15

    During recent years renewables have been acquiring gradually a significant importance in the world market (especially in the Spanish energetic market) and in society; this fact makes clear the need to increase and improve knowledge of these power sources. Starting from the results of a Life Cycle Assessment (LCA) of a multi-megawatt wind turbine, this work is aimed to assess the relevance of different choices that have been made during its development. Looking always to cover the largest possible spectrum of options, four scenarios have been analysed, focused on four main phases of lifecycle: maintenance, manufacturing, dismantling, and recycling. These scenarios facilitate to assess the degree of uncertainty of the developed LCA due to choices made, excluding from the assessment the uncertainty due to the inaccuracy and the simplification of the environmental models used or spatial and temporal variability in different parameters. The work has been developed at all times using the of Eco-indicator99 LCA method. (author)

  12. SOX sensitivity study

    Energy Technology Data Exchange (ETDEWEB)

    Martyn, Johann [Johannes Gutenberg-Universitaet, Mainz (Germany); Collaboration: BOREXINO-Collaboration

    2016-07-01

    To this day most experimental results on neutrino oscillations can be explained in the standard three neutrino model. There are however a few experiments that show anomalous behaviour at a very short baselines. These anomalies can hypothetically be explained with the existence of one or additional more light neutrino states that do not take part in weak interactions and are thus called sterile. Although the anomalies only give a hint that such sterile neutrinos could exist the prospect for physics beyond the standard model is a major motivation to investigate the neutrino oscillations in new very short baseline experiments. The SOX (Short distance Oscillations in BoreXino) experiment will use the Borexino detector and a {sup 144}Ce source to search for sterile neutrinos via the occurance of an oscillation pattern at a baseline of several meters. This talk examines the impact of the Borexino detector systematics on the experimental sensitivity of SOX.

  13. The development of an avian wind sensitivity map for South Africa

    Energy Technology Data Exchange (ETDEWEB)

    Retief, Ernst; Anderson, M. D.; Harebottle, D.; Jenkins, A.; Simmons, R.; Smit, H.A.; Rooyen, C. Van; Smallie, J.

    2011-07-01

    Full text: Wind energy is a relative new industry in South Africa. This provides South Africans with the opportunity to ensure that wind farms are placed in areas that are of low sensitivity to birds. With this in mind two environmental NGOs, BirdLife South Africa and the Endangered Wildlife Trust, designed an Avian Wind Sensitivity Map to provide guidance to the wind farm industry about the location of wind turbines. The map is the first of its kind in Africa. The purpose of the map is to provide an indication of the geographic areas in South Africa where the possible establishment of wind farms might have a negative impact on birds. Such a map will identify areas of bird sensitivity, i.e. sites where threatened, endemic and vulnerable bird species occur. The map was designed using a variety of data sources, specifically data acquired through citizen science projects - such as the Southern African Bird Atlas Project 2 and the Coordinated Waterbird Counts Project. The data were analysed using data priority scores based on the conservation concern of each species as well as the risk associated with a species to fly into wind turbines and associated infrastructures. The formal protection status of a geographic area was also taken into account. Extensive use was made of GIS tools to collate, analyse and present the data. A number of African countries are considering establishing wind farms. The lessons learnt during the design process can be used by other African countries as the basis for similar maps which can serve as a mitigation measure against the loss of vulnerable species. (Author)

  14. A Dynamic Wind Generation Model for Power Systems Studies

    OpenAIRE

    Estanqueiro, Ana

    2007-01-01

    In this paper, a wind park dynamic model is presented together with a base methodology for its application to power system studies. This detailed wind generation model addresses the wind turbine components and phenomena more relevant to characterize the power quality of a grid connected wind park, as well as the wind park response to the grid fast perturbations, e.g., low voltage ride through fault. The developed model was applied to the operating conditions of the selected sets of wind turbi...

  15. Sensitivity Analysis of Wind Plant Performance to Key Turbine Design Parameters: A Systems Engineering Approach; Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Dykes, K.; Ning, A.; King, R.; Graf, P.; Scott, G.; Veers, P.

    2014-02-01

    This paper introduces the development of a new software framework for research, design, and development of wind energy systems which is meant to 1) represent a full wind plant including all physical and nonphysical assets and associated costs up to the point of grid interconnection, 2) allow use of interchangeable models of varying fidelity for different aspects of the system, and 3) support system level multidisciplinary analyses and optimizations. This paper describes the design of the overall software capability and applies it to a global sensitivity analysis of wind turbine and plant performance and cost. The analysis was performed using three different model configurations involving different levels of fidelity, which illustrate how increasing fidelity can preserve important system interactions that build up to overall system performance and cost. Analyses were performed for a reference wind plant based on the National Renewable Energy Laboratory's 5-MW reference turbine at a mid-Atlantic offshore location within the United States.

  16. Asymmetry of wind waves studied in a laboratory tank

    Directory of Open Access Journals (Sweden)

    I. A. Leykin

    1995-01-01

    Full Text Available Asymmetry of wind waves was studied in laboratory tank tinder varied wind and fetch conditions using both bispectral analysis of wave records and third-order statistics of the surface elevation. It is found skewness S (the normalized third-order moment of surface elevation describing the horizontal asymmetry waves varies only slightly with the inverse wave u*/Cm (where u* is the air friction velocity and Cm is phase speed of the dominant waves. At the same time asymmetry A, which is determined from the Hilbert transform of the wave record and characterizes the skewness of the rate of change of surface elevation, increase consistently in magnitude with the ratio u*/Cm. This suggests that nonlinear distortion of the wave profile determined by the degree of wind forcing and is a sensitive indicator of wind-wave interaction processes. It is shown that the asymmetric profile of waves can described within the frameworks of the nonlinear nonspectral concept (Plate, 1972; Lake and Yuen, 197 according to which the wind-wave field can be represented as a coherent bound-wave system consisting mainly of dominant component w. and its harmonics propagating with the same speed C. , as observed by Ramamonjiaris and Coantic (1976. The phase shift between o. harmonics is found and shown to increase with the asymmetry of the waves.

  17. Asymmetry of wind waves studied in a laboratory tank

    Science.gov (United States)

    Ileykin, L. A.; Donelan, M. A.; Mellen, R. H.; McLaughlin, D. J.

    1995-03-01

    Asymmetry of wind waves was studied in laboratory tank tinder varied wind and fetch conditions using both bispectral analysis of wave records and third-order statistics of the surface elevation. It is found skewness S (the normalized third-order moment of surface elevation describing the horizontal asymmetry waves) varies only slightly with the inverse wave u*/Cm (where u* is the air friction velocity and Cm is phase speed of the dominant waves). At the same time asymmetry A, which is determined from the Hilbert transform of the wave record and characterizes the skewness of the rate of change of surface elevation, increase consistently in magnitude with the ratio u*/Cm. This suggests that nonlinear distortion of the wave profile determined by the degree of wind forcing and is a sensitive indicator of wind-wave interaction processes. It is shown that the asymmetric profile of waves can described within the frameworks of the nonlinear nonspectral concept (Plate, 1972; Lake and Yuen, 197 according to which the wind-wave field can be represented as a coherent bound-wave system consisting mainly of dominant component w. and its harmonics propagating with the same speed C. , as observed by Ramamonjiaris and Coantic (1976). The phase shift between o). harmonics is found and shown to increase with the asymmetry of the waves.

  18. Airfoil data sensitivity analysis for actuator disc simulations used in wind turbine applications

    International Nuclear Information System (INIS)

    Nilsson, Karl; Breton, Simon-Philippe; Ivanell, Stefan; Sørensen, Jens N

    2014-01-01

    To analyse the sensitivity of blade geometry and airfoil characteristics on the prediction of performance characteristics of wind farms, large-eddy simulations using an actuator disc (ACD) method are performed for three different blade/airfoil configurations. The aim of the study is to determine how the mean characteristics of wake flow, mean power production and thrust depend on the choice of airfoil data and blade geometry. In order to simulate realistic conditions, pre-generated turbulence and wind shear are imposed in the computational domain. Using three different turbulence intensities and varying the spacing between the turbines, the flow around 4-8 aligned turbines is simulated. The analysis is based on normalized mean streamwise velocity, turbulence intensity, relative mean power production and thrust. From the computations it can be concluded that the actual airfoil characteristics and blade geometry only are of importance at very low inflow turbulence. At realistic turbulence conditions for an atmospheric boundary layer the specific blade characteristics play an minor role on power performance and the resulting wake characteristics. The results therefore give a hint that the choice of airfoil data in ACD simulations is not crucial if the intention of the simulations is to compute mean wake characteristics using a turbulent inflow

  19. Sensitivity of Nodal Admittances in an Offshore Wind Power Plant to Parametric Variations in the Collection Grid

    DEFF Research Database (Denmark)

    Vytautas, Kersiulis; Holdyk, Andrzej; Holbøll, Joachim

    2012-01-01

    The paper presents sensitivity studies on nodal admittances in the offshore wind farm to different parameters of the collection grid cable system, including length of cable sections and actual layout configuration. The main aspect of this investigation is to see how parametric variations influence...... admittance and, consequently, voltage transfer in frequency domain. The simulation model of the offshore wind farm was build based on the main components in turbines and the collection grid. The simulation results were compared with data from time domain measurements and showed good agreement. A number...... of nodes were selected for evaluation of the admittances: the connection point to the external grid, a point at the substation and at each wind turbine. The results show that at specific locations resonances occur, where the admittance increases significantly in the 10-100 kHz range, depending...

  20. Wind to Hydrogen in California: Case Study

    Energy Technology Data Exchange (ETDEWEB)

    Antonia, O.; Saur, G.

    2012-08-01

    This analysis presents a case study in California for a large scale, standalone wind electrolysis site. This is a techno-economic analysis of the 40,000 kg/day renewable production of hydrogen and subsequent delivery by truck to a fueling station in the Los Angeles area. This quantity of hydrogen represents about 1% vehicle market penetration for a city such as Los Angeles (assuming 0.62 kg/day/vehicle and 0.69 vehicles/person) [8]. A wind site near the Mojave Desert was selected for proximity to the LA area where hydrogen refueling stations are already built.

  1. Pre-feasibility study of 80mw onshore wind farm

    International Nuclear Information System (INIS)

    Almas, M.S.

    2014-01-01

    This paper discusses a pre-feasibility study of 80MW onshore wind farm in the KPK (Khyber Pakhtunkhwa) province previously known as NWFP (North West Frontier) Province of Pakistan. The realistic data of wind speed is collected from Laboratory of Meteorology and Climatology (University of the Punjab) to study the feasibility of wind farm. Detailed analysis of wind turbines from four different manufacturers is carried out together with justifications of selecting a particular wind turbine. Issues related to site selection, wind farm civil foundation, recommendations for a particular choice of tower along with environmental effects are presented. Wind data analysis is carried out by using WINDROSE PRO software to determine the resultant direction of wind at the selected site for wind farm layout. The wind distribution at hub height of the wind turbine is calculated and is used to compute annual power production by the wind farm using power curves of the wind turbine. Electrical network integration issues of wind farm to the external grid are studied and the optimum point of connection is proposed. Finally, economic analysis of the whole wind farm project depending upon the LCC (Life Cycle Cost Analysis) is presented and the feasibility of the project from the investor's point of view is identified. The study concludes that the cost per kilowatt hour of electricity generated by this wind power plant will be 10.4 PKR/kWh and the payback period for the whole project is about 11.2 years. (author)

  2. Pre-Feasibility Study of 80MW Onshore Wind Farm

    Directory of Open Access Journals (Sweden)

    Muhammad Shoaib Almas

    2014-10-01

    Full Text Available This paper discusses a pre-feasibility study of 80MW onshore wind farm in the KPK (Khyber Pakhtunkhwa province previously known as NWFP (North West Frontier Province of Pakistan. The realistic data of wind speed is collected from Laboratory of Meteorology & Climatology (University of the Punjab to study the feasibility of wind farm. Detailed analysis of wind turbines from four different manufacturers is carried out together with justifications of selecting a particular wind turbine. Issues related to site selection, wind farm civil foundation, recommendations for a particular choice of tower along with environmental effects are presented. Wind data analysis is carried out by using WINDROSE PRO software to determine the resultant direction of wind at the selected site for wind farm layout. The wind distribution at hub height of the wind turbine is calculated and is used to compute annual power production by the wind farm using power curves of the wind turbine. Electrical network integration issues of wind farm to the external grid are studied and the optimum point of connection is proposed. Finally, economic analysis of the whole wind farm project depending upon the LCC (Life Cycle Cost Analysis is presented and the feasibility of the project from the investor?s point of view is identified. The study concludes that the cost per kilowatt hour of electricity generated by this wind power plant will be 10.4 PKR/kWh and the payback period for the whole project is about 11.2 years

  3. Nova Scotia wind integration study : final report

    International Nuclear Information System (INIS)

    2008-01-01

    An independent study was commissioned by the Nova Scotia Department of Energy to identify and assess the impacts of integrating large scale wind power generation into Nova Scotia's electric power system. The purpose of the study was to help Nova Scotia's efforts towards building its renewable energy supply, in order to secure a local energy resource and to protect the environment. This report provided an overview of Nova Scotia's electric power sector, including organizations involved; existing generation system; existing transmission system; renewable energy standards; Nova Scotia Power integrated resource plan; and 2007 renewable energy request for proposals. The major assumptions for the study that were discussed included system parameters; system capacity reserve requirements; expansion plans to 2020; and allocation of new wind generation by zone. Wind resource data and system dispatch modeling were also presented and transmission system modeling was outlined. This included a discussion of steady state reliability requirements; inputs to the load flow model; load flow study and contingency analysis; intra-province transmission congestion; and potential impacts on system security. The report also presented an approach to impact analysis and mitigation such as the impact on greenhouse gas and other air emissions and the impact of wind energy prices on system costs. It was concluded that one of the most important factors in evaluation of the economic impact of wind power integration is the forecasted fuel prices for the thermal units. If the fuel prices had varied significantly from the forecasted values, the study economic impact results could have been quite different. 55 tabs., 64 figs., 1 appendix

  4. Sensitive quench detection of the HTS coil using a co-winding coil

    International Nuclear Information System (INIS)

    Takagi, Tomohiro; Ariyama, Takahiro; Takao, Tomoaki; Tsukamoto, Osami

    2017-01-01

    The authors have studied the co-winding coil method (CW method) using the co-wound coil electrically insulated from the HTS coil. In this method, the quench is detected by the voltage difference between the coil of the HTS tape (HTS coil) and the coil of the normal conductor (CW coil). The voltage induced in the CW coil caused by the change of the magnetic field is almost the same as that in the HTS coil because the coils are magnetically coupled close to each other. Therefore, it is expected that the induced voltage will be canceled with high accuracy and that the resistive voltage in the HTS coil will be detected with greater sensitivity compared to the bridge balance method, which is used commonly. In this study, quench detection applying the CW method is demonstrated using an experimental double-pancake coil. A tape with the copper layer deposited on the polymer substrate was used as the insulated conductor wire to form the CW coil. An additional pancake coil was used to expose the experimental double-pancake coil to the external magnetic field asymmetrically. It was shown that the CW method can detect the resistive voltage with greater sensitivity even when the HTS coil was exposed to the changing asymmetric external magnetic field. (author)

  5. Sensitivity Analysis of Expected Wind Extremes over the Northwestern Sahara and High Atlas Region.

    Science.gov (United States)

    Garcia-Bustamante, E.; González-Rouco, F. J.; Navarro, J.

    2017-12-01

    A robust statistical framework in the scientific literature allows for the estimation of probabilities of occurrence of severe wind speeds and wind gusts, but does not prevent however from large uncertainties associated with the particular numerical estimates. An analysis of such uncertainties is thus required. A large portion of this uncertainty arises from the fact that historical observations are inherently shorter that the timescales of interest for the analysis of return periods. Additional uncertainties stem from the different choices of probability distributions and other aspects related to methodological issues or physical processes involved. The present study is focused on historical observations over the Ouarzazate Valley (Morocco) and in a high-resolution regional simulation of the wind in the area of interest. The aim is to provide extreme wind speed and wind gust return values and confidence ranges based on a systematic sampling of the uncertainty space for return periods up to 120 years.

  6. Sensitivity of ocean oxygenation to variations in tropical zonal wind stress magnitude

    Science.gov (United States)

    Ridder, Nina N.; England, Matthew H.

    2014-09-01

    Ocean oxygenation has been observed to have changed over the past few decades and is projected to change further under global climate change due to an interplay of several mechanisms. In this study we isolate the effect of modified tropical surface wind stress conditions on the evolution of ocean oxygenation in a numerical climate model. We find that ocean oxygenation varies inversely with low-latitude surface wind stress. Approximately one third of this response is driven by sea surface temperature anomalies; the remaining two thirds result from changes in ocean circulation and marine biology. Global mean O2 concentration changes reach maximum values of +4 μM and -3.6 μM in the two most extreme perturbation cases of -30% and +30% wind change, respectively. Localized changes lie between +92 μM under 30% reduced winds and -56 μM for 30% increased winds. Overall, we find that the extent of the global low-oxygen volume varies with the same sign as the wind perturbation; namely, weaker winds reduce the low-oxygen volume on the global scale and vice versa for increased trade winds. We identify two regions, one in the Pacific Ocean off Chile and the other in the Indian Ocean off Somalia, that are of particular importance for the evolution of oxygen minimum zones in the global ocean.

  7. Application of Ensemble Sensitivity Analysis to Observation Targeting for Short-term Wind Speed Forecasting in the Tehachapi Region Winter Season

    Energy Technology Data Exchange (ETDEWEB)

    Zack, John [AWS Truepower, LLC, Albany, NY (United States); Natenberg, Eddie [AWS Truepower, LLC, Albany, NY (United States); Young, Steve [AWS Truepower, LLC, Albany, NY (United States); Van Knowe, Glenn [AWS Truepower, LLC, Albany, NY (United States); Waight, Ken [AWS Truepower, LLC, Albany, NY (United States); Manobainco, John [AWS Truepower, LLC, Albany, NY (United States); Kamath, Chandrika [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2010-10-20

    This study extends the wind power forecast sensitivity work done by Zack et al. (2010a, b) in two prior research efforts. Zack et al. (2010a, b) investigated the relative predictive value and optimal combination of different variables/locations from correlated sensitivity patterns. Their work involved developing the Multiple Observation Optimization Algorithm (MOOA) and applying the algorithm to the results obtained from the Ensemble Sensitivity Analysis (ESA) method (Ancell and Hakim 2007; Torn and Hakim 2008).

  8. Wind Turbine and Wind Power Plant Modelling Aspects for Power System Stability Studies

    DEFF Research Database (Denmark)

    Altin, Müfit; Hansen, Anca Daniela; Göksu, Ömer

    2014-01-01

    Large amount of wind power installations introduce modeling challenges for power system operators at both the planning and operational stages of power systems. Depending on the scope of the study, the modeling details of the wind turbine or the wind power plant are required to be different. A wind...... turbine model which is developed for the short-term voltage stability studies can be inaccurate and sufficient for the frequency stability studies. Accordingly, a complete and detailed wind power plant model for every kind of study is not feasible in terms of the computational time and also...... and wind power plants are reviewed for power system stability studies. Important remarks of the models are presented by means of simulations to emphasize the impact of these modelling details on the power system....

  9. National Offshore Wind Energy Grid Interconnection Study Executive Summary

    Energy Technology Data Exchange (ETDEWEB)

    Daniel, John P. [ABB, Inc., Cary, NC (United States); Liu, Shu [ABB, Inc., Cary, NC (United States); Ibanez, Eduardo [National Renewable Energy Lab. (NREL), Golden, CO (United States); Pennock, Ken [AWS Truepower, Albany, NY (United States); Reed, Gregory [Univ. of Pittsburgh, PA (United States); Hanes, Spencer [Duke Energy, Charlotte, NC (United States)

    2014-07-30

    The National Offshore Wind Energy Grid Interconnection Study (NOWEGIS) considers the availability and potential impacts of interconnecting large amounts of offshore wind energy into the transmission system of the lower 48 contiguous United States.

  10. Nebraska Statewide Wind Integration Study: April 2008 - January 2010

    Energy Technology Data Exchange (ETDEWEB)

    EnerNex Corporation, Knoxville, Tennessee; Ventyx, Atlanta, Georgia; Nebraska Power Association, Lincoln, Nebraska

    2010-03-01

    Wind generation resources in Nebraska will play an increasingly important role in the environmental and energy security solutions for the state and the nation. In this context, the Nebraska Power Association conducted a state-wide wind integration study.

  11. National Offshore Wind Energy Grid Interconnection Study Full Report

    Energy Technology Data Exchange (ETDEWEB)

    Daniel, John P. [ABB, Inc., Cary, NC (United States); Liu, Shu [ABB, Inc., Cary, NC (United States); Ibanez, Eduardo [National Renewable Energy Lab. (NREL), Golden, CO (United States); Pennock, Ken [AWS Truepower, Albany, NY (United States); Reed, Gregory [Univ. of Pittsburgh, PA (United States); Hanes, Spencer [Duke Energy, Charlotte, NC (United States)

    2014-07-30

    The National Offshore Wind Energy Grid Interconnection Study (NOWEGIS) considers the availability and potential impacts of interconnecting large amounts of offshore wind energy into the transmission system of the lower 48 contiguous United States.

  12. Alternative Design Study Report: WindPACT Advanced Wind Turbine Drive Train Designs Study; November 1, 2000 -- February 28, 2002

    Energy Technology Data Exchange (ETDEWEB)

    Poore, R.; Lettenmaier, T.

    2003-08-01

    This report presents the Phase I results of the National Renewable Energy Laboratory's (NREL's) WindPACT (Wind Partnership for Advanced Component Technologies) Advanced Wind Turbine Drive Train Designs Study. Global Energy Concepts, LLC performed this work under a subcontract with NREL. The purpose of the WindPACT project is to identify technology improvements that will enable the cost of energy (COE) from wind turbines to be reduced. Other parts of the WindPACT project have examined blade and logistics scaling, balance-of-station costs, and rotor design. This study was designed to investigate innovative drive train designs.

  13. Wind energy market study Eastern Europe. Czech and Slovak Republics

    International Nuclear Information System (INIS)

    Skjerk Christensen, P.

    1994-06-01

    The main objective of the THERMIE Associated Measure WE05 is to study the conditions for utilising wind power and estimate the market for wind power in Eastern Europe. This report describes the results of a study of the conditions in the Czech and Slovak republics, which has been concentrated on the following areas: A collection of information on the wind energy potential in these countries and the present structure of the power production system including costs; A search for information concerning payback prices, subsidies, etc. with relation to renewable energy sources, especially wind power, existing wind turbines and their production; An estimate of the possibilities for co-production of wind turbines by Czech, Slovak, and EC factories; A compilation of information on rules and legislation pertaining to the establishment of wind turbines and to power production by wind, e.g. regulations related to grid connections, safety, and environmental production. In order to promote the utilisation of wind power in the Czech and Slovak Republics, some recommendations based on this study may be put forward: the operation of pilot plants should be evaluated in order to compare the recorded production with that which is estimated theoretically based on measured wind data. Existing wind data should be supplemented with new measurements especially at sites that based on current knowledge may be suitable for establishing wind parks. The economic feasibility of wind power in these countries should be calculated based on the best available physical and economic data. (EG)

  14. Base line studies North Sea wind farms

    NARCIS (Netherlands)

    Krijgsveld, K.L.; Lieshout, S.M.J.; Schekkerman, H.; Lensink, Rick; Poot, M.J.M.; Dirksen, S.

    2003-01-01

    The Dutch government has granted ‘Noordzeewind’ (Nuon Renewable Energy Projects and Shell Wind Energy) the possibility to build a wind farm consisting of 36 wind turbines off the coast of the Netherlands, near Egmond. This project serves to evaluate the economical, technical, ecological and social

  15. A feasibility study on a wind energy investment fund

    International Nuclear Information System (INIS)

    Mitchell, R.; Vassall-Adams, G.; Lynch, M.; Coates, S.; Willcox, S.

    1994-01-01

    This study seeks to overcome an obstacle to greater use of wind energy in Britain - the difficulties experienced by developers of small wind farms in raising finance for their projects. This need for capital has provided the impetus for this investigation into the possibility of wind funds, which would enable investors to invest in wind energy and provide developers of small wind farms with the financial backing they need. The contents of this report reflect the issues which would be of interest to an organisation wishing to establish a wind fund. These include the environmental concerns which have spurred the development of sustainable energy technologies, the role of government in establishing the framework for wind energy generation in Britain and public concern about the impact of wind farms. (author)

  16. Incorporating forecast uncertainties into EENS for wind turbine studies

    Energy Technology Data Exchange (ETDEWEB)

    Toh, G.K.; Gooi, H.B. [School of EEE, Nanyang Technological University, Singapore 639798 (Singapore)

    2011-02-15

    The rapid increase in wind power generation around the world has stimulated the development of applicable technologies to model the uncertainties of wind power resulting from the stochastic nature of wind and fluctuations of demand for integration of wind turbine generators (WTGs). In this paper the load and wind power forecast errors are integrated into the expected energy not served (EENS) formulation through determination of probabilities using the normal distribution approach. The effects of forecast errors and wind energy penetration in the power system are traversed. The impact of wind energy penetration on system reliability, total cost for energy and reserve procurement is then studied for a conventional power system. The results show a degradation of system reliability with significant wind energy penetration in the generation system. This work provides a useful insight into system reliability and economics for the independent system operator (ISO) to deploy energy/reserve providers when WTGs are integrated into the existing power system. (author)

  17. Electrical system studies for the grid connection of wind farms

    International Nuclear Information System (INIS)

    Arp, K.; Hanson, J.; Hopp, S.; Zimmermann, W.

    2007-01-01

    Wind power is gaining momentum in the world's energy balance. Several issues have to be addressed whenever power-generating devices are connected to the grid. The paper describes studies needed to evaluate the influence of wind farms on the connected transmission system and how faults in the system impact on induction generators in a wind farm. Some generalized results of studies for an offshore wind farm in the North Sea and a Bulgarian wind farm show how studies can influence the layout of the internal network and the electrical equipment. (authors)

  18. Studying Wind Energy/Bird Interactions: A Guidance Document

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, R. [California Energy Commission (US); Morrison, M. [California State Univ., Sacramento, CA (US); Sinclair, K. [Dept. of Energy/National Renewable Energy Lab. (US); Strickland, D. [WEST, Inc. (US)

    1999-12-01

    This guidance document is a product of the Avian Subcommittee of the National Wind Coordinating Committee (NWCC). The NWCC was formed to better understand and promote responsible, credible, and comparable avian/wind energy interaction studies. Bird mortality is a concern and wind power is a potential clean and green source of electricity, making study of wind energy/bird interactions essential. This document provides an overview for regulators and stakeholders concerned with wind energy/bird interactions, as well as a more technical discussion of the basic concepts and tools for studying such interactions.

  19. Application of transfer function based harmonic study method to an offshore wind farm

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Yu; Bollen, Math [STRI AB, Gothenburg (Sweden); Martins, Marcia [Alstom Wind, Barcelona (Spain)

    2012-07-01

    This paper presents the results from a harmonic study for a planned offshore wind farm with 252 MW installed capacity. Both the collection grid and the public grid are modelled in detail using Powerfactory. Both primary emission from wind turbines and secondary emission due to the distortion in the public grid are studied. Besides, due to the presence of HVDC platform and another two wind farms, details of which are not known at the moment, a sensitivity analysis is conducted to investigate the potential influence on the harmonic emission. (orig.)

  20. Design Study of Fully Superconducting Wind Turbine Generators

    DEFF Research Database (Denmark)

    Song, Xiaowei (Andy); Mijatovic, Nenad; Jensen, Bogi Bech

    2015-01-01

    In this paper, two fully superconducting generators employing MgB2 armature winding, with YBCO and MgB2 field winding respectively, are presented and analyzed. The ac loss in armature winding is estimated, and a simple comparative study is carried out. The results show that both electromagnetic...... designs for fully superconducting generators are promising with respect to the power density. However, the cost of removing ac loss in armature winding is as high as $900 000. It is also noted that with the current price of YBCO tape, the generator employing MgB 2 field winding would have lower cost....

  1. CanWEA Pan-Canadian wind integration study paper

    Energy Technology Data Exchange (ETDEWEB)

    Tremblay, Martin [GL Garrad Hassan Canada Inc, Ottawa, ON (Canada); Gardner, Paul [GL Garrad Hassan and Partners, Glasgow (United Kingdom); Price, Doug; Le, Don [GL Garrad Hassan America, San Diego, CA (United States)

    2010-07-01

    GL Garrad Hassan has been contracted by CanWEA to undertake a scoping study for a future Pan-Canadian Wide-Scale Wind Integration Study. The scoping study provides the methodology and the rationale on which the actual wind integration study and request for proposals will be based on. Major system operators and owners of each Canadian Province along with experts involved in major US wind integration studies have been consulted and contributed to the decisional process. This paper provides a summary of the factors considered in the study and outline the actual methodology that was adopted for the future Pan-Canadian wind integration study. (orig.)

  2. European wind power integration study. Periodic report 1

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1992-12-31

    This periodic report no. 1 describes the work done in the Danish part of the European Wind Power Integration Study in the period until 1.4.1991. The R and D project was initiated January 1, 1989 upon prior establishment of registration equipment at 7 wind farms and at the Tjaereborg turbine. ELSAM and the meteorological service centre in Karup (VTC-Karup) have supplied data for the task. Wind Predictability, Potential and Benefits, Wind Farm - Grid Interface, Distribution System Strength, Wind Farm Cost and Operation, and Co-generation Wind Turbines/Other renewables were measured and modelled. The statistical distribution of the wind speed variations (changes in wind speed from one period of time to another) has been established with great certainty in the report. The wind speed variations follow a Weibull distribution, irrespective of the time intervals with which the data are considered. Duration curves and power distributions for the 7 wind farms have been estimated. Registration equipment for one-minute measurements was chosen in order to clarify the short-term variations in the wind power production. The possibility of working out production forecasts, to be applied in the daily load dispatching, were to be assessed for the total amount of wind power production in Jutland and Funen. The report has examined whether it would be possible to have only one wind measurement and then let it be `guiding` for the total wind farm production. Some simulations are to be carried out in the attempt to set up guidelines for the connection between the strength of distribution systems and the requirements which must be made to the wind farms which are to be places in the system. (EG)

  3. Wind resource and plant output data sets for wind integration studies

    Energy Technology Data Exchange (ETDEWEB)

    Frank, Jaclyn D.; Manobianco, John; Alonge, Charles J.; Brower, Michael C. [AWS Truepower, Albany, NY (United States)

    2010-07-01

    One of the first step towards understanding the impact of increasing penetrations of wind is developing data sets of wind power output over large regions. To facilitate the development of these data sets, AWS Truepower (AWST) generated wind speeds over multiple years (2-3) using the Mesoscale Atmospheric Simulation System (MASS). These simulations were performed with high spatial resolution (1-2 km) to capture the wind flows over each area of interest. Output was saved in 10-minute interval to capture variations in wind speed so that plant output could be analyzed against utility load and system operations. This paper will describe the methodology of mesoscale modeling, site selection, conversion to power, and downscaling to high frequency output. Additionally, the generation of synthetic forecasts will be discussed. The validation results from recent studies in the eastern United States and Hawaii will be highlighted. (orig.)

  4. Application of the Tikhonov regularization method to wind retrieval from scatterometer data I. Sensitivity analysis and simulation experiments

    International Nuclear Information System (INIS)

    Zhong Jian; Huang Si-Xun; Du Hua-Dong; Zhang Liang

    2011-01-01

    Scatterometer is an instrument which provides all-day and large-scale wind field information, and its application especially to wind retrieval always attracts meteorologists. Certain reasons cause large direction error, so it is important to find where the error mainly comes. Does it mainly result from the background field, the normalized radar cross-section (NRCS) or the method of wind retrieval? It is valuable to research. First, depending on SDP2.0, the simulated ‘true’ NRCS is calculated from the simulated ‘true’ wind through the geophysical model function NSCAT2. The simulated background field is configured by adding a noise to the simulated ‘true’ wind with the non-divergence constraint. Also, the simulated ‘measured’ NRCS is formed by adding a noise to the simulated ‘true’ NRCS. Then, the sensitivity experiments are taken, and the new method of regularization is used to improve the ambiguity removal with simulation experiments. The results show that the accuracy of wind retrieval is more sensitive to the noise in the background than in the measured NRCS; compared with the two-dimensional variational (2DVAR) ambiguity removal method, the accuracy of wind retrieval can be improved with the new method of Tikhonov regularization through choosing an appropriate regularization parameter, especially for the case of large error in the background. The work will provide important information and a new method for the wind retrieval with real data. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

  5. Wind energy in electric power production. Preliminary study

    Energy Technology Data Exchange (ETDEWEB)

    Lento, R; Peltola, E

    1984-01-15

    The wind speed conditions in Finland have been studied with the aid of the existing statistics of the Finnish Meteorological Institute. With the aid of the statistics also estimates on the available wind energy were made. 800 wind power plants, 1.5 MW each, on the windiest west coast would produce about 2 TWh energy per year. Far more information on the temporal, geographical and vertical distribution of the wind speed than the present statistics include is needed when the available wind energy is estimated, when wind power plants are dimensioned optimally, and when suitable locations are chosen for them. The investment costs of a wind power plant increase when the height of the tower or the diameter of the rotor is increased, but the energy production increases, too. Thus, overdimensioning the wind power plant in view of energy needs or the wind conditions causes extra costs. The cost of energy produced by wind power can not yet compete with conventional energy, but the situation changes to the advantage of wind energy, if the real price of the plants decreases (among other things due to large series production and increasing experience), or if the real price of fuels rises. The inconvinience on the environment caused by the wind power plants is considered insignificant. The noise caused by the plant attenuates rapidly with distance. No harmful effects birds and other animals caused by the wind power plants have been observed in the studies made abroad. Parts of a plant getting loose during an accident, or ice forming on the blades are estimated to fly even from a large plant only a few hundred meters.

  6. IEA Wind Task 24 Integration of Wind and Hydropower Systems; Volume 2: Participant Case Studies

    Energy Technology Data Exchange (ETDEWEB)

    Acker, T.

    2011-12-01

    This report describes the background, concepts, issues and conclusions related to the feasibility of integrating wind and hydropower, as investigated by the members of IEA Wind Task 24. It is the result of a four-year effort involving seven IEA member countries and thirteen participating organizations. The companion report, Volume 2, describes in detail the study methodologies and participant case studies, and exists as a reference for this report.

  7. Black Sea Mixed Layer Sensitivity to Various Wind and Thermal Forcing Products on Climatological Time Scales

    National Research Council Canada - National Science Library

    Kara, A. B; Jurlburt, Harley; Wallcraft, Alan; Bourassa, Mark

    2005-01-01

    This study describes atmospheric forcing parameters constructed from different global climatologies, applied to the Black Sea, and investigates the sensitivity of HYbrid Coordinate Ocean Model (HYCOM...

  8. Feasibility study on the wind farm; Wind farm no kanosei chosa

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-03-01

    For assessment of the possibility of the wind farm (collective wind power facility) in Japan, site conditions, business plans and various issues in development were arranged using some projects in a planning stage. The case study of a system design was also conducted for a typical site. Four sites were selected based on geographical conditions, topographic features and weather conditions. Scales of every site are as large as 1000-3000kW and 400- 750kW in wind turbine capacity. Every developer expects a subsidy, and governmental economic support is indispensable for the wind farm. In the case of Hisai city, Mie prefecture with the most favorable wind condition in Japan, the annual mean wind velocity of the site is valued at nearly 8m/s, suggesting that it is promising for the wind farm. From the planned scale of 750kWtimes4, the annual generated power and availability factor are valued at 9,800,000kWh/y and 37%, respectively. From the construction cost of 1 billion yen including a subsidy of its half, the generation cost is valued at 14.5 yen/kWh in durability of 15 years, and 12.2 yen/kWh in 20 years, and the profitability is dependent on the purchase price of a power company. 27 figs., 36 tabs.

  9. Preliminary manual of the wind farms impacts study

    International Nuclear Information System (INIS)

    2000-11-01

    This document aims to present and propose tools and methods allowing the improve the environmental quality of the future wind farms projects. After a presentation of general notions on the wind farms and the economy of the wind energy, it presents the regulation and the procedures concerning the environmental impact. It proposes then the main possible effects and the impacts study themes. (A.L.B.)

  10. Repository design sensitivity study: Engineering study report

    International Nuclear Information System (INIS)

    1987-01-01

    A preliminary sensitivity study of the salt repository design has been performed to identify critical site and design parameters to help guide future site characterization and design optimization activities. The study considered the SCP-conceptual design at the Deaf Smith County site in Texas with the horizontal waste package emplacement mode as the base case. Relative to this base case, parameter variations were compared. Limited studies were performed which considered the vertical emplacement mode geometry. The report presents the reference data base and design parameters on which the study was based (including the range of parameters that might be expected). Detailed descriptions of the numerical modeling methods and assumptions are included for the thermal, thermomechanical and hydrogeological analyses. The impacts of parameter variations on the sensitivity of the rock mass response are discussed. Recommendations are provided to help guide site characterization activities and advanced conceptual design optimization activities. 47 refs., 119 refs., 22 tabs

  11. Wind tunnel experimental study on the effect of PAM on soil wind erosion control.

    Science.gov (United States)

    He, Ji-Jun; Cai, Qiang-Guo; Tang, Ze-Jun

    2008-10-01

    In recent years, high-molecular-weight anionic polyacrylamide (PAM) have been widely tested on a variety of soils, primarily in water erosion control. However, little information is available regarding the effectiveness of PAM on preventing soil loss from wind erosion. The research adopted room wind tunnel experiment, two kinds of soils were used which were from the agro-pastoral area of Inner Mongolia, the northwest of China, the clay content of soils were 22.0 and 13.7%, respectively. For these tests, all the treatments were performed under the condition of wind velocity of 14 m s(-1) and a blown angle of 8.75%, according to the actual situation of experimented area. The study results indicated that using PAM on the soil surface could enhance the capability of avoiding the wind erosion, at the same time, the effect of controlling wind soil erosion with 4 g m(-2) PAM was better than 2 g m(-2) PAM's. Economically, the 2 g m(-2) PAM used in soil surface can control wind erosion effectively in this region. The prophase PAM accumulated in soil could not improve the capability of avoiding the wind erosion, owing to the degradation of PAM in the soil and the continual tillage year after year. The texture of soil is a main factor influencing the capability of soil avoiding wind erosion. Soil with higher clay content has the higher capability of preventing soil from wind erosion than one with the opposite one under the together action of PAM and water.

  12. Vortex system studies on small wind turbines

    Energy Technology Data Exchange (ETDEWEB)

    Montgomerie, Bjoern; Dahlberg, Jan-Aake [Swedish Defence Research Agency, Stockholm (Sweden). Div. of Aeronautics, FFA

    2003-10-01

    The wind tunnel experiment reported included a small wind turbine setup and smoke to visualize the trailing tip vortices for different wind turbine configurations. Several combinations of tunnel wind speeds and tip speed ratios generated a database where the end result functions were radius and pitch, of the tip vortex spirals, versus the downstream coordinate. The Reynolds number in the experiment was very low compared to that of full size turbines. The results should therefore be seen as valid only for low Reynolds numbers. The models were 18 and 25 cm diameter turbines. This is thought to be complementary to the information obtained in similar wind tunnel investigations for much larger models. The database is meant to be a fundamental tool for the construction of practical aerodynamic induction methods. Such methods typically employ the Biot-Savart law has been shown to lead to a flow field, which deviates considerably from that of reality. E.g. concentration into tip vortices does not happen when the flow is simulated with Biot-Savart law only. Thus, a combination of the induction method and its modification, based on investigations such as the one reported, is foreseen to replace the widely used Blade Element Momentum method for wind turbine loads and performance prediction.

  13. Enhanced Dynamic Voltage Stability Support by VSC-HVDC for Offshore Wind Applications using Trajectory Sensitivity Analysis

    DEFF Research Database (Denmark)

    Liu, Hongzhi; Chen, Zhe; Liu, Leo

    2013-01-01

    The integration of large-scale wind power plants changes the structure, configuration and operation of conventional power systems and brings challenges to the security and stability of power systems. Dynamic voltage stability of power systems with high wind penetration is one of the critical issues....... In this paper, VSC-HVDC transmission system is used to integrate a large-scale wind power plant into the onshore power grid. For different voltage support strategies of VSC-HVDC, a trajectory sensitivity analysisbased approach is proposed to find the minimum onshore VSC capacity with which the VSC-HVDC can...... provide enough support for the improvement of system voltage stability after a disturbance. Sensitivities of reactive power output of VSC to its capacity increase are calculated instead of the sensitivities of bus voltage magnitude towards the reactive power injection variation of VSC. Simulation results...

  14. Complete wind farm electromagnetic transient modelling for grid integration studies

    International Nuclear Information System (INIS)

    Zubia, I.; Ostolaza, X.; Susperregui, A.; Tapia, G.

    2009-01-01

    This paper presents a modelling methodology to analyse the impact of wind farms in surrounding networks. Based on the transient modelling of the asynchronous generator, the multi-machine model of a wind farm composed of N generators is developed. The model incorporates step-up power transformers, distribution lines and surrounding loads up to their connection to the power network. This model allows the simulation of symmetric and asymmetric short-circuits located in the distribution network and the analysis of transient stability of wind farms. It can be also used to study the islanding operation of wind farms

  15. Wind tunnel study of the power output spectrum in a micro wind farm

    International Nuclear Information System (INIS)

    Bossuyt, Juliaan; Meyers, Johan; Howland, Michael F.; Meneveau, Charles

    2016-01-01

    Instrumented small-scale porous disk models are used to study the spectrum of a surrogate for the power output in a micro wind farm with 100 models of wind turbines. The power spectra of individual porous disk models in the first row of the wind farm show the expected -5/3 power law at higher frequencies. Downstream models measure an increased variance due to wake effects. Conversely, the power spectrum of the sum of the power over the entire wind farm shows a peak at the turbine-to-turbine travel frequency between the model turbines, and a near -5/3 power law region at a much wider range of lower frequencies, confirming previous LES results. Comparison with the spectrum that would result when assuming that the signals are uncorrelated, highlights the strong effects of correlations and anti-correlations in the fluctuations at various frequencies. (paper)

  16. Climate change drives wind turbines in China: case study of market based wind power development

    Energy Technology Data Exchange (ETDEWEB)

    Ming Yang [EET Consulting, Glen Waverley, Victoria (Australia)

    2004-07-01

    This paper aims at quantifying the impact of government policy and clean development mechanism (CDM) on wind power development in China. Firstly we review the background of Chinese wind power development and policy, as well as literature of climate change and CDM. We then present methodology, scenarios and data of a case study for the development of a large-scale grid-connected wind farm. We undertake project financial analysis under three scenarios. Our analysis results show that the project FIRR is 8.31% if CDM benefit is not taken into account, 8.72% if CDM benefit is considered with the price of the certified emission reduction (CER) at US dollars 4, and 10.28% if both the CDM benefit and government policy on cutting value added tax (VAT) by 50% are taken into account. This paper concludes that CDM and government preferential policy on value added tax will make wind power development financially viable in China. (author)

  17. Limitations of wind power availability over Europe: a conceptual study

    Directory of Open Access Journals (Sweden)

    P. Kiss

    2008-11-01

    Full Text Available Wind field statistics are evaluated from the ERA-40 data bank covering a period of 44 years with a temporal resolution of 6 h. Instantaneous wind speed values are provided in geographic cells of size 1°×1° (lat/long for surface (10 m and 1000 hPa pressure heights. Potential wind power generation is estimated in two steps. Firstly, the wind speed at hub height is approximated from surface data based on the statistical analysis of the wind and geopotential records for 1000 hPa pressure level. Secondly, the wind speed values are transformed by an idealised power curve fitted for measured data. The model time series are fed into various hypothetical electric networks. The main quantity of interest is the aggregated output from the networks. A reference power time series is determined for a static network connecting each continental site and an envelope of 1° around the shorelines (representing off-shore locations over Europe. This time series exhibits a low average value and a marked annual periodicity. Wind power integration over limited areas results in higher average outputs at the expense of stronger fluctuations. The long-range spatial correlations of the wind field limit the level of fluctuations strongly which can not be eliminated either by an increase of the area of integration or by dynamic control. This study is fully conceptual, however it demonstrates the limitations of wind power integration over Europe.

  18. Comparative study of Danish and foreign wind turbine economics

    International Nuclear Information System (INIS)

    Godtfredsen, F.

    1993-02-01

    This comparative study indicates that Denmark still is the leading nation in wind turbine technology in regard to economics as well as energy output and nacelle weight per swept rotor area. For roughness class 1, the levellized socioeconomic costs of wind power from Danish wind turbines is DKK 0.396 - 0.536 per kWh compared with production costs of DKK 0.525 for the most economic of the foreign wind turbines investigated. Furthermore it is pointed out, that there seems to be no correlation between generator capacity or swept rotor area and costs of windpower for the wind turbines investigated. Nevertheless there are arguments for the statement that large scale wind turbines will be relatively more economic in the future. Danish wind turbine manufacturers only produce tree-bladed, stall- or pitch regulated wind turbines with constant rotational speed. In Holland, Germany and UK two-bladed wind turbines and turbines with variable speed has been introduced. Still the new concepts are less economic, but not without future interest. (au)

  19. Innovative Offshore Wind Plant Design Study

    Energy Technology Data Exchange (ETDEWEB)

    Hurley, William L. [Glosten Associates, Inc., Seattle, WA (United States); Nordstrom, Charles J. [Glosten Associates, Inc., Seattle, WA (United States); Morrison, Brent J. [Glosten Associates, Inc., Seattle, WA (United States)

    2013-12-18

    Technological advancements in the Glosten PelaStar floating wind turbine system have led to projected cost of energy (COE) reductions from today’s best-in-class offshore wind systems. The PelaStar system is projected to deliver a COE that is 35% lower than that delivered by the current offshore wind plants. Several technology developments have been achieved that directly target significant cost of energy reductions. These include: Application of state-of-the-art steel construction materials and methods, including fatigue-resistant welding techniques and technologies, to reduce hull steel weight; Advancements in synthetic fiber tendon design for the mooring system, which are made possible by laboratory analysis of full-scale sub-rope specimens; Investigations into selected anchor technologies to improve anchor installation methods; Refinement of the installation method, specifically through development of the PelaStar Support Barge design. Together, these technology developments drive down the capital cost and operating cost of offshore wind plants and enable access to superb wind resources in deep water locations. These technology developments also reduce the uncertainty of the PelaStar system costs, which increases confidence in the projected COE reductions.

  20. Satellite retrieved cloud optical thickness sensitive to surface wind speed in the subarctic marine boundary layer

    International Nuclear Information System (INIS)

    Glantz, Paul

    2010-01-01

    The optical and microphysical properties of low level marine clouds, presented over the Norwegian Sea and Barents Sea, have been investigated for the period 2000-2006. The air masses were transported for more or less seven days over the warmer North Atlantic before they arrived at the area investigated. The main focus in this study is on investigating the relationship between cloud optical thickness (COT) and surface wind speed (U 10m ) using satellite retrievals in combination with operational meteorological data. A relatively strong correlation (R 2 = 0.97) is obtained for wind speeds up to 12 m s -1 , in air masses that were probably to a major degree influenced by wind shears and to a minor degree by buoyancy. The relationship (U 2.5 ) is also in between those most commonly found in the literature for water vapor (∼U 1 ) and sea salt (∼U 3.4 ). The present results highlight the magnitude of marine sea-spray influence on COT and their global climatic importance.

  1. Feasibility Study for a Hopi Utility-Scale Wind Project

    Energy Technology Data Exchange (ETDEWEB)

    Kendrick Lomayestewa

    2011-05-31

    The goal of this project was to investigate the feasibility for the generation of energy from wind and to parallel this work with the development of a tribal utility organization capable of undertaking potential joint ventures in utility businesses and projects on the Hopi reservation. The goal of this project was to investigate the feasibility for the generation of energy from wind and to parallel this work with the development of a tribal utility organization capable of undertaking potential joint ventures in utility businesses and projects on the Hopi reservation. Wind resource assessments were conducted at two study sites on Hopi fee simple lands located south of the city of Winslow. Reports from the study were recently completed and have not been compared to any existing historical wind data nor have they been processed under any wind assessment models to determine the output performance and the project economics of turbines at the wind study sites. Ongoing analysis of the wind data and project modeling will determine the feasibility of a tribal utility-scale wind energy generation.

  2. The Western Wind and Solar Integration Study Phase 2

    Energy Technology Data Exchange (ETDEWEB)

    Lew, Debra [National Renewable Energy Lab. (NREL), Golden, CO (United States); Brinkman, Greg [National Renewable Energy Lab. (NREL), Golden, CO (United States); Ibanez, E. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Florita, A. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Heaney, M. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Hodge, B. -M. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Hummon, M. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Stark, G. [National Renewable Energy Lab. (NREL), Golden, CO (United States); King, J. [RePPAE; Lefton, S. A. [Intertek-APTECH, Houston, TX (United States); Kumar, N. [Intertek-APTECH, Houston, TX (United States); Agan, D. [Intertek-APTECH, Houston, TX (United States); Jordan, G. [GE Energy, Fairfield, CT (United States); Venkataraman, S. [GE Energy, Fairfield, CT (United States)

    2013-09-01

    The electric grid is a highly complex, interconnected machine, and changing one part of the grid can have consequences elsewhere. Adding wind and solar affects the operation of the other power plants and adding high penetrations can induce cycling of fossil-fueled generators. Cycling leads to wear-and-tear costs and changes in emissions. Phase 2 of the Western Wind and Solar Integration Study (WWSIS-2) evaluated these costs and emissions and simulated grid operations for a year to investigate the detailed impact of wind and solar on the fossil-fueled fleet. This built on Phase 1, one of the largest wind and solar integration studies ever conducted, which examined operational impacts of high wind and solar penetrations in the West(GE Energy 2010).

  3. The Western Wind and Solar Integration Study Phase 2

    Energy Technology Data Exchange (ETDEWEB)

    Lew, D.; Brinkman, G.; Ibanez, E.; Hodge, B. M.; Hummon, M.; Florita, A.; Heaney, M.

    2013-09-01

    The electric grid is a highly complex, interconnected machine, and changing one part of the grid can have consequences elsewhere. Adding wind and solar affects the operation of the other power plants and adding high penetrations can induce cycling of fossil-fueled generators. Cycling leads to wear-and-tear costs and changes in emissions. Phase 2 of the Western Wind and Solar Integration Study (WWSIS-2) evaluated these costs and emissions and simulated grid operations for a year to investigate the detailed impact of wind and solar on the fossil-fueled fleet. This built on Phase 1, one of the largest wind and solar integration studies ever conducted, which examined operational impacts of high wind and solar penetrations in the West.

  4. Wave Tank Studies of Phase Velocities of Short Wind Waves

    Science.gov (United States)

    Ermakov, S.; Sergievskaya, I.; Shchegolkov, Yu.

    Wave tank studies of phase velocities of short wind waves have been carried out using Ka-band radar and an Optical Spectrum Analyser. The phase velocities were retrieved from measured radar and optical Doppler shifts, taking into account measurements of surface drift velocities. The dispersion relationship was studied in centimetre (cm)- and millimetre(mm)-scale wavelength ranges at different fetches and wind speeds, both for a clean water surface and for water covered with surfactant films. It is ob- tained that the phase velocities do not follow the dispersion relation of linear capillary- gravity waves, increasing with fetch and, therefore, depending on phase velocities of dominant decimetre (dm)-centimetre-scale wind waves. One thus can conclude that nonlinear cm-mm-scale harmonics bound to the dominant wind waves and propagat- ing with the phase velocities of the decimetric waves are present in the wind wave spectrum. The resulting phase velocities of short wind waves are determined by re- lation between free and bound waves. The relative intensity of the bound waves in the spectrum of short wind waves is estimated. It is shown that this relation depends strongly on the surfactant concentration, because the damping effect due to films is different for free and bound waves; this results to changes of phase velocities of wind waves in the presence of surfactant films. This work was supported by MOD, UK via DERA Winfrith (Project ISTC 1774P) and by RFBR (Project 02-05-65102).

  5. European wind integration study (EWIS). Towards a successful integration of large scale wind power into European electricity grids. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Winter, W.

    2010-03-15

    representations of the existing electricity markets, network operations, and the physical power flows and other system behaviours that result. The starting point was the actual conditions in 2008 with future challenges assessed against realistic representations of network extensions and reinforcements taken from national development plans. In general, detailed information on user and network developments are only available for a limited number of future years and so 2015 was chosen as a suitable horizon for assessing how current plans will address future challenges. Given the importance of the 2020 targets, however, the study examined the prospects for further developments beyond 2015. In EWIS, scenarios and sensitivity cases were used to explore the following uncertainties concerning conditions in 2015: 5) The nature of future generation developments, especially the total capacity of wind generation installations. 6) The impacts of fuel and CO{sub 2} prices. 7) The effect of different wind patterns across Europe. (LN)

  6. Bird interactions with wind turbines : a Canadian case study

    Energy Technology Data Exchange (ETDEWEB)

    Brown, K.; Hamilton, B. [TAEM Ltd., Calgary, AB (Canada)

    2004-07-01

    An environmental study has been conducted on a wind farm adjacent to Castle River, in the foothills of the Rocky Mountains in Alberta. The objective was to determine the impact of the many wind turbines on birds. The study involved observations of different bird species including raptors, waterfowl and passerines. The observations looked at bird numbers, location relative to turbines, and changes in flight pattern. The study found that raptors flew around or over the turbine blades, while passerines remained below, and waterfowl flew up and over the blades. Very few dead birds were found over the monitoring period, suggesting that wind turbines do not have a major impact on birds. figs.

  7. Proposed Wind Turbine Aeroelasticity Studies Using Helicopter Systems Analysis

    Science.gov (United States)

    Ladkany, Samaan G.

    1998-01-01

    Advanced systems for the analysis of rotary wing aeroelastic structures (helicopters) are being developed at NASA Ames by the Rotorcraft Aeromechanics Branch, ARA. The research has recently been extended to the study of wind turbines, used for electric power generation Wind turbines play an important role in Europe, Japan & many other countries because they are non polluting & use a renewable source of energy. European countries such as Holland, Norway & France have been the world leaders in the design & manufacture of wind turbines due to their historical experience of several centuries, in building complex wind mill structures, which were used in water pumping, grain grinding & for lumbering. Fossil fuel cost in Japan & in Europe is two to three times higher than in the USA due to very high import taxes. High fuel cost combined with substantial governmental subsidies, allow wind generated power to be competitive with the more traditional sources of power generation. In the USA, the use of wind energy has been limited mainly because power production from wind is twice as expensive as from other traditional sources. Studies conducted at the National Renewable Energy Laboratories (NREL) indicate that the main cost in the production of wind turbines is due to the materials & the labor intensive processes used in the construction of turbine structures. Thus, for the US to assume world leadership in wind power generation, new lightweight & consequently very flexible wind turbines, that could be economically mass produced, would have to be developed [4,5]. This effort, if successful, would result in great benefit to the US & the developing nations that suffer from overpopulation & a very high cost of energy.

  8. Studying wind power-bird interactions during the next decade

    Energy Technology Data Exchange (ETDEWEB)

    Holder, M. [TransAlta Wind, Calgary, AB (Canada)

    2010-07-01

    This PowerPoint presentation described TransAlta's ongoing study of wind power and bird interactions, and outlined the company's plans for the future. The deaths of large birds were noticed by the public as well as by the operators of wind farms built in response to the energy crisis of the 1970s. Post-construction casualty monitoring was established in 1994 in order to understand the direct effects of wind power projects on birds as well as to amass data and identify the broader issues affecting bird mortalities. Increased regulatory rigour led to a further clarification of the techniques used to monitor bird deaths. A study of the amassed data demonstrated that birds were not being killed in large numbers, but that common bird species in a given area were the most common casualties observed at wind farms. Particular species were not predisposed to be at risk. Significant declines in bird species have been noted in Canada, and many population declines have occurred in species located in landscapes well-suited for wind farms. The declines have meant that more scrutiny is placed on wind development projects and their potential cumulative effect. The direct effects of wind turbines on birds are not yet well-understood. The requirements for pre- and post-construction data collection must be reviewed and amended. Future studies will consider bird casualties as well as habitat and behavioural changes. tabs., figs.

  9. Western Wind and Solar Integration Study: Phase 2 (Presentation)

    Energy Technology Data Exchange (ETDEWEB)

    Lew, D.; Brinkman, G.; Ibanez, E.; Lefton, S.; Kumar, N.; Venkataraman, S.; Jordan, G.

    2013-09-01

    This presentation summarizes the scope and results of the Western Wind and Solar Integration Study Phase 2, which examined operational impacts of high penetrations of variable renewable generation in the West.

  10. Hurricane Resilient Wind Plant Concept Study Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Dibra, Besart [Keystone Engineering Inc., Vonore, TN (United States); Finucane, Zachary [Keystone Engineering Inc., Vonore, TN (United States); Foley, Benjamin [Keystone Engineering Inc., Vonore, TN (United States); Hall, Rudy [Keystone Engineering Inc., Vonore, TN (United States); Damiani, Rick [National Renewable Energy Lab. (NREL), Golden, CO (United States); Maples, Benjamin [National Renewable Energy Lab. (NREL), Golden, CO (United States); Parker, Zachary [National Renewable Energy Lab. (NREL), Golden, CO (United States); Robertson, Amy [National Renewable Energy Lab. (NREL), Golden, CO (United States); Scott, George [National Renewable Energy Lab. (NREL), Golden, CO (United States); Stehly, Tyler [National Renewable Energy Lab. (NREL), Golden, CO (United States); Wendt, Fabian [National Renewable Energy Lab. (NREL), Golden, CO (United States); Andersen, Mads Boel Overgaard [Siemens Wind Power A/S, Brande (Denmark); Standish, Kevin [Siemens Wind Power A/S, Brande (Denmark); Lee, Ken [Wetzel Engineering Inc., Round Rock, TX (United States); Raina, Amool [Wetzel Engineering Inc., Round Rock, TX (United States); Wetzel, Kyle [Wetzel Engineering Inc., Round Rock, TX (United States); Musial, Walter [National Renewable Energy Lab. (NREL), Golden, CO (United States); Schreck, Scott [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2016-10-01

    Hurricanes occur over much of the U.S. Atlantic and Gulf coasts, from Long Island to the U.S.-Mexico border, encompassing much of the nation's primary offshore wind resource. Category 5 hurricanes have made landfall as far north as North Carolina, with Category 3 hurricanes reaching New York with some frequency. Along the US West coast, typhoons strike with similar frequency and severity. At present, offshore wind turbine design practices do not fully consider the severe operating conditions imposed by hurricanes. Although universally applied to most turbine designs, International Electrotechnical Commission (IEC) standards do not sufficiently address the duration, directionality, magnitude, or character of hurricanes. To assess advanced design features that could mitigate hurricane loading in various ways, this Hurricane-Resilient Wind Plant Concept Study considered a concept design study of a 500-megawatt (MW) wind power plant consisting of 10-MW wind turbines deployed in 25-meter (m) water depths in the Western Gulf of Mexico. This location was selected because hurricane frequency and severity provided a unique set of design challenges that would enable assessment of hurricane risk and projection of cost of energy (COE) changes, all in response to specific U.S. Department of Energy (DOE) objectives. Notably, the concept study pursued a holistic approach that incorporated multiple advanced system elements at the wind turbine and wind power plant levels to meet objectives for system performance and reduced COE. Principal turbine system elements included a 10-MW rotor with structurally efficient, low-solidity blades; a lightweight, permanent-magnet, direct-drive generator, and an innovative fixed substructure. At the wind power plant level, turbines were arrayed in a large-scale wind power plant in a manner aimed at balancing energy production against capital, installation, and operation and maintenance (O&M) costs to achieve significant overall reductions in

  11. Evaluation of annoyance from the wind turbine noise: A pilot study

    Directory of Open Access Journals (Sweden)

    Małgorzata Pawlaczyk-Łuszczyńska

    2014-07-01

    Full Text Available Objectives: The overall aim of this study was to evaluate the perception of and annoyance due to the noise from wind turbines in populated areas of Poland. Material and Methods: The study group comprised 156 subjects. All subjects were asked to fill in a questionnaire developed to enable evaluation of their living conditions, including prevalence of annoyance due to the noise from wind turbines and the self-assessment of physical health and well-being. In addition, current mental health status of the respondents was assessed using Goldberg General Health Questionnaire GHQ-12. For areas where the respondents lived, A-weighted sound pressure levels (SPLs were calculated as the sum of the contributions from the wind power plants in the specific area. Results: It has been shown that the wind turbine noise at the calculated A-weigh­ted SPL of 30-48 dB was noticed outdoors by 60.3% of the respondents. This noise was perceived as annoying outdoors by 33.3% of the respondents, while indoors by 20.5% of them. The odds ratio of being annoyed outdoors by the wind turbine noise increased along with increasing SPLs (OR = 2.1; 95% CI: 1.22-3.62. The subjects' attitude to wind turbines in general and sensitivity to landscape littering was found to have significant impact on the perceived annoyance. About 63% of variance in outdoors annoyance assessment might be explained by the noise level, general attitude to wind turbines and sensitivity to landscape littering. Conclusions: Before firm conclusions can be drawn further studies are needed, including a larger number of respondents with different living environments (i.e., dissimilar terrain, different urbanization and road traffic intensity.

  12. Structural Health and Prognostics Management for Offshore Wind Turbines: Sensitivity Analysis of Rotor Fault and Blade Damage with O&M Cost Modeling

    Energy Technology Data Exchange (ETDEWEB)

    Myrent, Noah J. [Vanderbilt Univ., Nashville, TN (United States). Lab. for Systems Integrity and Reliability; Barrett, Natalie C. [Vanderbilt Univ., Nashville, TN (United States). Lab. for Systems Integrity and Reliability; Adams, Douglas E. [Vanderbilt Univ., Nashville, TN (United States). Lab. for Systems Integrity and Reliability; Griffith, Daniel Todd [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Wind Energy Technology Dept.

    2014-07-01

    Operations and maintenance costs for offshore wind plants are significantly higher than the current costs for land-based (onshore) wind plants. One way to reduce these costs would be to implement a structural health and prognostic management (SHPM) system as part of a condition based maintenance paradigm with smart load management and utilize a state-based cost model to assess the economics associated with use of the SHPM system. To facilitate the development of such a system a multi-scale modeling and simulation approach developed in prior work is used to identify how the underlying physics of the system are affected by the presence of damage and faults, and how these changes manifest themselves in the operational response of a full turbine. This methodology was used to investigate two case studies: (1) the effects of rotor imbalance due to pitch error (aerodynamic imbalance) and mass imbalance and (2) disbond of the shear web; both on a 5-MW offshore wind turbine in the present report. Sensitivity analyses were carried out for the detection strategies of rotor imbalance and shear web disbond developed in prior work by evaluating the robustness of key measurement parameters in the presence of varying wind speeds, horizontal shear, and turbulence. Detection strategies were refined for these fault mechanisms and probabilities of detection were calculated. For all three fault mechanisms, the probability of detection was 96% or higher for the optimized wind speed ranges of the laminar, 30% horizontal shear, and 60% horizontal shear wind profiles. The revised cost model provided insight into the estimated savings in operations and maintenance costs as they relate to the characteristics of the SHPM system. The integration of the health monitoring information and O&M cost versus damage/fault severity information provides the initial steps to identify processes to reduce operations and maintenance costs for an offshore wind farm while increasing turbine availability

  13. Study of applying a hybrid standalone wind-photovoltaic generation system

    Directory of Open Access Journals (Sweden)

    Aissa Dahmani

    2015-01-01

    Full Text Available The purpose of this paper is the study of applying a hybrid system wind/photovoltaic to supply a community in southern Algeria. Diesel generators are always used to provide such remote regions with energy. Using renewable energy resources is a good alternative to overcome such pollutant generators. Hybrid Optimization Model for Electric Renewable (HOMER software is used to determine the economic feasibility of the proposed configuration. Assessment of renewable resources consisting in wind and solar potentials, load profile determination and sensitivity of different parameters analysis were performed. The cost of energy (COE of 0.226 $/kWh is very competitive with those found in literature.

  14. A comparative study of various inflow boundary conditions and turbulence models for wind turbine wake predictions

    Science.gov (United States)

    Tian, Lin-Lin; Zhao, Ning; Song, Yi-Lei; Zhu, Chun-Ling

    2018-05-01

    This work is devoted to perform systematic sensitivity analysis of different turbulence models and various inflow boundary conditions in predicting the wake flow behind a horizontal axis wind turbine represented by an actuator disc (AD). The tested turbulence models are the standard k-𝜀 model and the Reynolds Stress Model (RSM). A single wind turbine immersed in both uniform flows and in modeled atmospheric boundary layer (ABL) flows is studied. Simulation results are validated against the field experimental data in terms of wake velocity and turbulence intensity.

  15. Spin-off wind energy. A study on the economic, sustainability and regional effects of wind energy

    International Nuclear Information System (INIS)

    Terbijhe, A.; Oltmer, K.; Van der Voort, M.

    2009-09-01

    This study focuses on collecting and organizing information. This information can be used as the basis for a policy line by the Dutch Ministry of Agriculture, Nature and Food Quality (LNV) for wind energy in agricultural companies. The aim of the project is to gain insight in: (1) the possible role of agricultural wind energy in the national energy supply; (2) the current and future business economic effects of wind energy on the agricultural farm; and (3) the current and future effect of wind energy on the local rural economy in general and specifically the economic meaning of wind energy for the regional economy in the region of Flevoland. [nl

  16. Condensation of long-term wave climates for the fatigue design of hydrodynamically sensitive offshore wind turbine support structures

    DEFF Research Database (Denmark)

    Passon, Patrik; Branner, Kim

    2016-01-01

    important for hydrodynamically sensitive structures since the applied met-ocean parameters have a non-linear influence on calculated fatigue design loads. The present article introduces a new wave lumping method for condensation of the wave climate. The novelty is predominantly based on refined equivalence......Cost-efficient and reliable fatigue designs of offshore wind turbine support structures require an adequate representation of the site-specific wind–wave joint distribution. Establishment of this wind–wave joint distribution for design load calculation purposes requires typically a correlation...... of the marginal wind and wave distribution. This is achieved by condensation of the site-specific wave climate in terms of wave period or wave height lumping, subsequently used as input for a correlation with the corresponding wind climate. The quality of this resulting wind–wave correlation is especially...

  17. Measuring sensitivity in pharmacoeconomic studies. Refining point sensitivity and range sensitivity by incorporating probability distributions.

    Science.gov (United States)

    Nuijten, M J

    1999-07-01

    The aim of the present study is to describe a refinement of a previously presented method, based on the concept of point sensitivity, to deal with uncertainty in economic studies. The original method was refined by the incorporation of probability distributions which allow a more accurate assessment of the level of uncertainty in the model. In addition, a bootstrap method was used to create a probability distribution for a fixed input variable based on a limited number of data points. The original method was limited in that the sensitivity measurement was based on a uniform distribution of the variables and that the overall sensitivity measure was based on a subjectively chosen range which excludes the impact of values outside the range on the overall sensitivity. The concepts of the refined method were illustrated using a Markov model of depression. The application of the refined method substantially changed the ranking of the most sensitive variables compared with the original method. The response rate became the most sensitive variable instead of the 'per diem' for hospitalisation. The refinement of the original method yields sensitivity outcomes, which greater reflect the real uncertainty in economic studies.

  18. Predicting wind shear effects: A study of Minnesota wind data collected at heights up to 70 meters

    Energy Technology Data Exchange (ETDEWEB)

    Artig, R. [Minnesota Dept. of Public Service, St. Paul, MN (United States)

    1997-12-31

    The Minnesota Department of Public Service (DPS) collects wind data at carefully selected sites around the state and analyzes the data to determine Minnesota`s wind power potential. DPS recently installed advanced new monitoring equipment at these sites and began to collect wind data at 30, 50, and 70 meters above ground level, with two anemometers at each level. Previously, the Department had not collected data at heights above ground level higher than 30 meters. DPS also, with the U.S. Department of Energy (DOE), installed four sophisticated monitoring sites as part of a Tall Tower Wind Shear Study that is assessing the effects of wind shear on wind power potential. At these sites, wind data are being collected at the 10, 30, 40, 50, 60, and 70 meter heights. This paper presents the preliminary results of the analysis of wind data from all sites. These preliminary results indicate that the traditional 1/7 power law does not effectively predict wind shear in Minnesota, and the result is an underestimation of Minnesota`s wind power potential at higher heights. Using a power factor of 1/5 or 1/4 may be more accurate and provide sound justification for installing wind turbines on taller towers in Minnesota.

  19. Study of Wind Effects on Unique Buildings

    Science.gov (United States)

    Olenkov, V.; Puzyrev, P.

    2017-11-01

    The article deals with a numerical simulation of wind effects on the building of the Church of the Intercession of the Holy Virgin in the village Bulzi of the Chelyabinsk region. We presented a calculation algorithm and obtained pressure fields, velocity fields and the fields of kinetic energy of a wind stream, as well as streamlines. Computational fluid dynamic (CFD) evolved three decades ago at the interfaces of calculus mathematics and theoretical hydromechanics and has become a separate branch of science the subject of which is a numerical simulation of different fluid and gas flows as well as the solution of arising problems with the help of methods that involve computer systems. This scientific field which is of a great practical value is intensively developing. The increase in CFD-calculations is caused by the improvement of computer technologies, creation of multipurpose easy-to-use CFD-packagers that are available to a wide group of researchers and cope with various tasks. Such programs are not only competitive in comparison with physical experiments but sometimes they provide the only opportunity to answer the research questions. The following advantages of computer simulation can be pointed out: a) Reduction in time spent on design and development of a model in comparison with a real experiment (variation of boundary conditions). b) Numerical experiment allows for the simulation of conditions that are not reproducible with environmental tests (use of ideal gas as environment). c) Use of computational gas dynamics methods provides a researcher with a complete and ample information that is necessary to fully describe different processes of the experiment. d) Economic efficiency of computer calculations is more attractive than an experiment. e) Possibility to modify a computational model which ensures efficient timing (change of the sizes of wall layer cells in accordance with the chosen turbulence model).

  20. Theoretical design study of the MSFC wind-wheel turbine

    Science.gov (United States)

    Frost, W.; Kessel, P. A.

    1982-01-01

    A wind wheel turbine (WWT) is studied. Evaluation of the probable performance, possible practical applications, and economic viability as compared to other conventional wind energy systems is discussed. The WWT apparatus is essentially a bladed wheel which is directly exposed to the wind on the upper half and exposed to wind through multiple ducting on the lower half. The multiple ducts consist of a forward duct (front concentrator) and two side ducts (side concentrators). The forced rotation of the wheel is then converted to power through appropriate subsystems. Test results on two simple models, a paper model and a stainless steel model, are reported. Measured values of power coefficients over wind speeds ranging from 4 to 16 m/s are given. An analytical model of a four bladed wheel is also developed. Overall design features of the wind turbine are evaluated and discussed. Turbine sizing is specified for a 5 and 25 kW machine. Suggested improvements to the original design to increase performance and performance predictions for an improved WWT design are given.

  1. Western Wind and Solar Integration Study: Hydropower Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Acker, T.; Pete, C.

    2012-03-01

    The U.S. Department of Energy's (DOE) study of 20% Wind Energy by 2030 was conducted to consider the benefits, challenges, and costs associated with sourcing 20% of U.S. energy consumption from wind power by 2030. This study found that with proactive measures, no insurmountable barriers were identified to meet the 20% goal. Following this study, DOE and the National Renewable Energy Laboratory (NREL) conducted two more studies: the Eastern Wind Integration and Transmission Study (EWITS) covering the eastern portion of the U.S., and the Western Wind and Solar Integration Study (WWSIS) covering the western portion of the United States. The WWSIS was conducted by NREL and research partner General Electric (GE) in order to provide insight into the costs, technical or physical barriers, and operational impacts caused by the variability and uncertainty of wind, photovoltaic, and concentrated solar power when employed to serve up to 35% of the load energy in the WestConnect region (Arizona, Colorado, Nevada, New Mexico, and Wyoming). WestConnect is composed of several utility companies working collaboratively to assess stakeholder and market needs to and develop cost-effective improvements to the western wholesale electricity market. Participants include the Arizona Public Service, El Paso Electric Company, NV Energy, Public Service of New Mexico, Salt River Project, Tri-State Generation and Transmission Cooperative, Tucson Electric Power, Xcel Energy and the Western Area Power Administration.

  2. Parameter study of electric power production in wind farms - experiments using two model scale wind turbines

    OpenAIRE

    Ceccotti, Clio

    2015-01-01

    Wind farms are widely developed even if several unsolved problems need to be faced. The rotor-wake interaction involves different physical phenomena, not yet fully understood, directly affecting the overall wind farm power production. Numerical models and engineering rules have always been used to design wind farm layout but a spread between power predictions and results is verified. In this context wind energy research assumes a "back to basic" approach, by means of wind tunne...

  3. Wind tunnel study of a vertical axis wind turbine in a turbulent boundary layer flow

    Science.gov (United States)

    Rolin, Vincent; Porté-Agel, Fernando

    2015-04-01

    Vertical axis wind turbines (VAWTs) are in a relatively infant state of development when compared to their cousins the horizontal axis wind turbines. Very few studies have been carried out to characterize the wake flow behind VAWTs, and virtually none to observe the influence of the atmospheric boundary layer. Here we present results from an experiment carried out at the EPFL-WIRE boundary-layer wind tunnel and designed to study the interaction between a turbulent boundary layer flow and a VAWT. Specifically we use stereoscopic particle image velocimetry to observe and quantify the influence of the boundary layer flow on the wake generated by a VAWT, as well as the effect the VAWT has on the boundary layer flow profile downstream. We find that the wake behind the VAWT is strongly asymmetric, due to the varying aerodynamic forces on the blades as they change their position around the rotor. We also find that the wake adds strong turbulence levels to the flow, particularly on the periphery of the wake where vortices and strong velocity gradients are present. The boundary layer is also shown to cause greater momentum to be entrained downwards rather than upwards into the wake.

  4. A preliminary benefit-cost study of a Sandia wind farm.

    Energy Technology Data Exchange (ETDEWEB)

    Ehlen, Mark Andrew; Griffin, Taylor; Loose, Verne W.

    2011-03-01

    In response to federal mandates and incentives for renewable energy, Sandia National Laboratories conducted a feasibility study of installing an on-site wind farm on Sandia National Laboratories and Kirtland Air Force Base property. This report describes this preliminary analysis of the costs and benefits of installing and operating a 15-turbine, 30-MW-capacity wind farm that delivers an estimated 16 percent of 2010 onsite demand. The report first describes market and non-market economic costs and benefits associated with operating a wind farm, and then uses a standard life-cycle costing and benefit-cost framework to estimate the costs and benefits of a wind farm. Based on these 'best-estimates' of costs and benefits and on factor, uncertainty and sensitivity analysis, the analysis results suggest that the benefits of a Sandia wind farm are greater than its costs. The analysis techniques used herein are applicable to the economic assessment of most if not all forms of renewable energy.

  5. Comparison study between wind turbine and power kite wakes

    Science.gov (United States)

    Haas, T.; Meyers, J.

    2017-05-01

    Airborne Wind Energy (AWE) is an emerging technology in the field of renewable energy that uses kites to harvest wind energy. However, unlike for conventional wind turbines, the wind environment in AWE systems has not yet been studied in much detail. We propose a simulation framework using Large Eddy Simulation to model the wakes of such kite systems and offer a comparison with turbine-like wakes. In order to model the kite effects on the flow, a lifting line technique is used. We investigate different wake configurations related to the operation modes of wind turbines and airborne systems in drag mode. In the turbine mode, the aerodynamic torque of the blades is directly added to the flow. In the kite drag mode, the aerodynamic torque of the wings is directly balanced by an opposite torque induced by on-board generators; this results in a total torque on the flow that is zero. We present the main differences in wake characteristics, especially flow induction and vorticity fields, for the depicted operation modes both with laminar and turbulent inflows.

  6. Comparative Study Between Wind and Photovoltaic (PV) Systems

    Science.gov (United States)

    Taha, Wesam

    This paper reviews two renewable energy systems; wind and photovoltaic (PV) systems. The common debate between the two of them is to conclude which one is better, in terms of cost and efficiency. Therefore, comparative study, in terms of cost and efficiency, is attempted. Regarding total cost of both, wind and PV systems, many parameters must be taken into consideration such as availability of energy (either wind or solar), operation and maintenance, availability of costumers, political influence, and the components used in building the system. The main components and parameters that play major role in determining the overall efficiency of wind systems are the wind turbine generator (WTG), gearbox and control technologies such as power, and speed control. On the other hand, in grid-connected PV systems (GCPVS), converter architecture along with maximum power point tracking (MPPT) algorithm and inverter topologies are the issues that affects the efficiency significantly. Cost and efficiency analyses of both systems have been carried out based on the statistics available till today and would be useful in the progress of renewable energy penetration throughout the world.

  7. Direct employment in the wind energy sector: An EU study

    Energy Technology Data Exchange (ETDEWEB)

    Blanco, Maria Isabel [Department of Economic Analysis, University of Alcala de Henares, 28802 Alcala de Henares (Spain)], E-mail: isabel.blanco@ewea.org; Rodrigues, Gloria [Department of Economic Analysis, University of Alcala de Henares, 28802 Alcala de Henares (Spain)

    2009-08-15

    Wind energy is often said to have positive effects on employment, but few studies have systematically dealt with this matter. This article presents estimates of direct wind energy employment in all EU countries, gathered for the first time. By using a thematic survey, the authors have been able to analyse aspects such as gender distribution, company profiles and the shortage of skilled workers reported by wind energy companies. The outcomes show that wind energy deployment creates a significant number of jobs (over 104,000 in 2008), and does so at a time when other energy sectors are shrinking. There is a clear relationship between MW installed and number of jobs, but the use of a single EU job/MW ratio is not feasible, due to differences in the export/import capacity. Wind turbine manufacturers-including major sub-components-are responsible for the lion's share of the jobs, and there is a marked prevalence of males in the workforce. The scarcity of specialist roles-project managers, engineers and O and M technicians-is not likely to be solved unless a series of educational, mobility and dissemination measures are put into practice.

  8. Direct employment in the wind energy sector. An EU study

    Energy Technology Data Exchange (ETDEWEB)

    Blanco, Maria Isabel; Rodrigues, Gloria [Department of Economic Analysis, University of Alcala de Henares, 28802 Alcala de Henares (Spain)

    2009-08-15

    Wind energy is often said to have positive effects on employment, but few studies have systematically dealt with this matter. This article presents estimates of direct wind energy employment in all EU countries, gathered for the first time. By using a thematic survey, the authors have been able to analyse aspects such as gender distribution, company profiles and the shortage of skilled workers reported by wind energy companies. The outcomes show that wind energy deployment creates a significant number of jobs (over 104,000 in 2008), and does so at a time when other energy sectors are shrinking. There is a clear relationship between MW installed and number of jobs, but the use of a single EU job/MW ratio is not feasible, due to differences in the export/import capacity. Wind turbine manufacturers - including major sub-components - are responsible for the lion's share of the jobs, and there is a marked prevalence of males in the workforce. The scarcity of specialist roles - project managers, engineers and O and M technicians - is not likely to be solved unless a series of educational, mobility and dissemination measures are put into practice. (author)

  9. Direct employment in the wind energy sector: An EU study

    International Nuclear Information System (INIS)

    Blanco, Maria Isabel; Rodrigues, Gloria

    2009-01-01

    Wind energy is often said to have positive effects on employment, but few studies have systematically dealt with this matter. This article presents estimates of direct wind energy employment in all EU countries, gathered for the first time. By using a thematic survey, the authors have been able to analyse aspects such as gender distribution, company profiles and the shortage of skilled workers reported by wind energy companies. The outcomes show that wind energy deployment creates a significant number of jobs (over 104,000 in 2008), and does so at a time when other energy sectors are shrinking. There is a clear relationship between MW installed and number of jobs, but the use of a single EU job/MW ratio is not feasible, due to differences in the export/import capacity. Wind turbine manufacturers-including major sub-components-are responsible for the lion's share of the jobs, and there is a marked prevalence of males in the workforce. The scarcity of specialist roles-project managers, engineers and O and M technicians-is not likely to be solved unless a series of educational, mobility and dissemination measures are put into practice.

  10. Co-located wind-wave farm synergies (Operation and Maintenance): A case study

    International Nuclear Information System (INIS)

    Astariz, S.; Perez-Collazo, C.; Abanades, J.; Iglesias, G.

    2015-01-01

    Highlights: • The shielding effect of WECs located around the wind farm is analysed. • The height wave reductions achieved by 15 different layouts are compared. • The increase in the accessibility to the wind turbines is quantified. • Alpha Ventus offshore wind farm is considered as baseline scenario. • High-resolution numerical modelling (SWAN) and real sea conditions are used. - Abstract: Operation and maintenance can jeopardise the financial viability of an offshore wind energy project due to the cost of downtime, repairs and, above all, the inevitable uncertainties. The variability of wave climate can impede or hinder emergency repairs when a failure occurs, and the resulting delays imply additional costs which ultimately reduce the competitiveness of offshore wind energy as an alternative to fossil fuels. Co-located wind turbines and Wave Energy Converters (WECs) are proposed in this paper as a novel solution: the reduction of the significant wave height brought about by the WECs along the periphery of the wind farm results in a milder wave climate within the farm. This reduction, also called shadow effect, enlarges weather windows for Operation and Maintenance (O and M). The objective of this paper is to investigate the increase in the accessibility time to the turbines and to optimise the layout for the co-located wind-wave farm in order to maximise this time. The investigation is carried out through a case study: Alpha Ventus, an operating offshore wind farm. To maximise the reduction of wave height in the turbine area no fewer than 15 layouts are tested using high-resolution numerical modelling, and a sensitivity analysis is conducted. The results show that, thanks to the wave energy extraction by the WECs, weather windows (access time) can increase very significantly – over 80%. This substantial effect, together with other benefits from the combination of wave and offshore wind power in a co-located farm (common electrical infrastructures

  11. A verification study and trend analysis of simulated boundary layer wind fields over Europe

    Energy Technology Data Exchange (ETDEWEB)

    Lindenberg, Janna

    2011-07-01

    Simulated wind fields from regional climate models (RCMs) are increasingly used as a surrogate for observations which are costly and prone to homogeneity deficiencies. Compounding the problem, a lack of reliable observations makes the validation of the simulated wind fields a non trivial exercise. Whilst the literature shows that RCMs tend to underestimate strong winds over land these investigations mainly relied on comparisons with near surface measurements and extrapolated model wind fields. In this study a new approach is proposed using measurements from high towers and a robust validation process. Tower height wind data are smoother and thus more representative of regional winds. As benefit this approach circumvents the need to extrapolate simulated wind fields. The performance of two models using different downscaling techniques is evaluated. The influence of the boundary conditions on the simulation of wind statistics is investigated. Both models demonstrate a reasonable performance over flat homogeneous terrain and deficiencies over complex terrain, such as the Upper Rhine Valley, due to a too coarse spatial resolution ({proportional_to}50 km). When the spatial resolution is increased to 10 and 20 km respectively a benefit is found for the simulation of the wind direction only. A sensitivity analysis shows major deviations of international land cover data. A time series analysis of dynamically downscaled simulations is conducted. While the annual cycle and the interannual variability are well simulated, the models are less effective at simulating small scale fluctuations and the diurnal cycle. The hypothesis that strong winds are underestimated by RCMs is supported by means of a storm analysis. Only two-thirds of the observed storms are simulated by the model using a spectral nudging approach. In addition ''False Alarms'' are simulated, which are not detected in the observations. A trend analysis over the period 1961 - 2000 is conducted

  12. SLS Trade Study 0058: Day of Launch (DOL) Wind Biasing

    Science.gov (United States)

    Decker, Ryan K.; Duffin, Paul; Hill, Ashley; Beck, Roger; Dukeman, Greg

    2014-01-01

    SLS heritage hardware and legacy designs have shown load exceedances at several locations during Design Analysis Cycles (DAC): MPCV Z bending moments; ICPS Electro-Mechanical Actuator (EMA) loads; Core Stage loads just downstream of Booster forward interface. SLS Buffet Loads Mitigation Task Team (BLMTT) tasked to study issue. Identified low frequency buffet load responses are a function of the vehicle's total angle of attack (AlphaTotal). SLS DOL Wind Biasing Trade team to analyze DOL wind biasing methods to limit maximum AlphaTotal in the M0.8 - 2.0 altitude region for EM-1 and EM-2 missions through investigating: Trajectory design process; Wind wavelength filtering options; Launch availability; DOL process to achieve shorter processing/uplink timeline. Trade Team consisted of personnel supporting SLS, MPCV, GSDO programs.

  13. Generic 12-Bus Test System for Wind Power Integration Studies

    DEFF Research Database (Denmark)

    Adamczyk, Andrzej Grzegorz; Altin, Müfit; Göksu, Ömer

    2012-01-01

    , inertial response, frequency control, damping of electromechanical oscillations, balanced and unbalanced fault management, etc. Hence, the power system components: conventional power plants with controls, transmission lines, transformers and loads should be represented accurately to achieve realistic power......High wind power penetration levels into power systems requires an appropriate power system model when assessing impact on the overall system stability. The model should capture the wide range of dynamics related to the wind integration studies, such as voltage control, synchronizing power control...... system characteristics. Additionally, the power system model should be simple and computationally manageable in order to simulate multiple scenarios with different control parameters in a reasonable time. In this paper, a generic power system model is presented in order to comprehend the wind integration...

  14. Energy Policy Case Study - Texas: Wind, Markets, and Grid Modernization

    Energy Technology Data Exchange (ETDEWEB)

    Orrell, Alice C. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Homer, Juliet S. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Bender, Sadie R. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Weimar, Mark R. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2016-09-19

    This document presents a case study of energy policies in Texas related to power system transformation, renewable energy and distributed energy resources (DERs). Texas has experienced a dramatic increase in installed wind capacity, from 116 MW in 2000 to over 15,000 MW in 2015. This achievement was enabled by the designation of Competitive Renewable Energy Zones (CREZs) and new transmission lines that transmit wind to load centers. This report highlights nascent efforts to include DERs in the ERCOT market. As costs decline and adoption rates increase, ERCOT expects distributed generation to have an increasing effect on grid operations, while bringing potentially valuable new resources to the wholesale markets.

  15. Sensitivity of trajectory calculations to the temporal frequency of wind data

    Science.gov (United States)

    Doty, Kevin G.; Perkey, Donald J.

    1993-01-01

    A mesoscale primitive equation model is used to create a 36-h simulation of the three-dimensional wind field of an intense maritime extratropical cyclone. The control experiment uses the simulated wind field every 15 min in a trajectory model to calculate back trajectories from various horizontal and vertical positions of interest relative to synoptic features of the storm. The latter trajectories are compared to trajectories that were calculated with the simulated wind data degraded in time to 30 min, 1 h, 3 h, 6h, and 12 h. Various error statistics reveal significant deterioration in trajectory accuracy between trajectories calculated with 1- and 3-h data frequencies. Trajectories calculated with 15-min, 30-min, and 1-h data frequencies yielded similar results, while trajectories calculated with data time frequencies 3 h and greater yielded results with unacceptably large errors.

  16. CFD simulation for pedestrian wind comfort and wind safety in urban areas : general decision framework and case study for the Eindhoven University campus

    NARCIS (Netherlands)

    Blocken, B.J.E.; Janssen, W.D.; Hooff, van T.A.J.

    2012-01-01

    Wind comfort and wind safety for pedestrians are important requirements in urban areas. Many city authorities request studies of pedestrian wind comfort and wind safety for new buildings and new urban areas. These studies involve combining statistical meteorological data, aerodynamic information and

  17. Wind energy and power system operations: a review of wind integration studies to date

    Energy Technology Data Exchange (ETDEWEB)

    Cesaro, Jennifer de; Porter, Kevin; Milligan, Michael

    2009-12-15

    Wind integration will not be accomplished successfully by doing ''more of the same.'' It will require significant changes in grid planning and operations, continued technical evolution in the design and operation of wind turbines, further adoption and implementation of wind forecasting in the control room, and incorporation of market and policy initiatives to encourage more flexible generation. (author)

  18. Sensitivity of Gravity Wave Fluxes to Interannual Variations in Tropical Convection and Zonal Wind.

    Science.gov (United States)

    Alexander, M Joan; Ortland, David A; Grimsdell, Alison W; Kim, Ji-Eun

    2017-09-01

    Using an idealized model framework with high-frequency tropical latent heating variability derived from global satellite observations of precipitation and clouds, the authors examine the properties and effects of gravity waves in the lower stratosphere, contrasting conditions in an El Niño year and a La Niña year. The model generates a broad spectrum of tropical waves including planetary-scale waves through mesoscale gravity waves. The authors compare modeled monthly mean regional variations in wind and temperature with reanalyses and validate the modeled gravity waves using satellite- and balloon-based estimates of gravity wave momentum flux. Some interesting changes in the gravity spectrum of momentum flux are found in the model, which are discussed in terms of the interannual variations in clouds, precipitation, and large-scale winds. While regional variations in clouds, precipitation, and winds are dramatic, the mean gravity wave zonal momentum fluxes entering the stratosphere differ by only 11%. The modeled intermittency in gravity wave momentum flux is shown to be very realistic compared to observations, and the largest-amplitude waves are related to significant gravity wave drag forces in the lowermost stratosphere. This strong intermittency is generally absent or weak in climate models because of deficiencies in parameterizations of gravity wave intermittency. These results suggest a way forward to improve model representations of the lowermost stratospheric quasi-biennial oscillation winds and teleconnections.

  19. Cognitive-emotional sensitization contributes to wind-up-like pain in phantom limb pain patients

    DEFF Research Database (Denmark)

    Vase, Lene; Nikolajsen, Lone; Christensen, Bente

    2011-01-01

    ). Catastrophizing accounted for 35% of the variance in phantom limb pain (p=0.001) independently of anxiety and depression. Catastrophizing was also positively associated with wind-up-like pain in non-medicated patients (p=0.015), but not to pain thresholds. These findings suggest that cognitive-emotional...

  20. Sensitivity of a Navy Regional Ocean Model to High-Resolution Atmospheric and Scatterometer Wind Forcing

    Science.gov (United States)

    2003-09-01

    available until June 1999, synthetic QuikSCAT winds were generated using software provided by the Aerospace Corporation ( Stodden and Galasso, 1996...1994: Methods of Satellite Oceanography. Berkeley: University of California Press, 360 pp. Stodden , D.Y., and G.D. Galasso, 1996

  1. Hopf bifurcation and eigenvalue sensitivity analysis of doubly fed induction generator wind turbine system

    DEFF Research Database (Denmark)

    Yang, Li Hui; Xu, Zhao; Østergaard, Jacob

    2010-01-01

    This paper first presents the Hopf bifurcation analysis for a vector-controlled doubly fed induction generator (DFIG) which is widely used in wind power conversion systems. Using three-phase back-to-back pulse-width-modulated (PWM) converters, DFIG can keep stator frequency constant under variabl...

  2. Dependence of Substorm Evolution on Solar Wind Condition: Simulation Study

    Science.gov (United States)

    Kamiyoshikawa, N.; Ebihara, Y.; Tanaka, T.

    2017-12-01

    A substorm is one of the remarkable disturbances occurring in the magnetosphere. It is known that the substorm occurs frequently when IMF is southward and solar wind speed is high. However, the physical process to determine substorm scale is not well understood. We reproduced substorms by using global MHD simulation, calculated auroral electrojet (ionospheric Hall current) flowing in the ionosphere to investigate the dependence of substorm evolution on solar wind condition. Solar wind speed of 372.4 km/s and IMF Bz of 5.0 nT were imposed to, obtain the quasi-stationary state of the magnetosphere. Then the solar wind parameters were changed as a step function. For the solar wind speed, we assumed 300 km/s, 500 km/s and 700 km/s. For IMF, we assumed -1.0 nT, -3.0 nT, -5.0 nT, -7.0 nT and -9.0 nT. In total, 15 simulation runs were performed. In order to objectively evaluate the substorm, the onset was identified with the method based on the one proposed by Newell et al. (2011). This method uses the SME index that is an extension of the AE index. In this study, the geomagnetic variation induced by the ionospheric Hall current was obtained every 1 degree from the magnetic latitude 40 degrees to 80 degrees and in every 0.5 hours in the magnetic region direction. The upper and the lower envelopes of the geomagnetic variation are regarded as SMU index and SML index, respectively. The larger the solar wind speed, the larger the southward IMF, the more the onset tends to be faster. This tendency is consistent with the onset occurrence probability indicated by Newell et al. (2016). Moreover, the minimum value of the SML index within 30 minutes from the beginning of the onset tends to decrease with the solar wind speed and the magnitude of the southward IMF. A rapid decrease of the SML index can be explained by a rapid increase in the field-aligned currents flowing in and out of the nightside ionosphere. This means that electromagnetic energies flowing into the ionosphere

  3. A study on the survey of wind energy resources for potential areas

    Energy Technology Data Exchange (ETDEWEB)

    Park, Kyung Ho; Kim, Keon Hoon; Yoo, Seung Won; Choi, Chang Joon; Ahn, Jung Jong [Korea Inst. of Energy Research, Taejon (Korea, Republic of)

    1995-12-01

    Among the wind energy utilization projects, the siting work for wind turbine installation is one of the most important procedure because the wind energy distribution is very different regionally and wind energy density influences greatly to the feasibility of wind energy utilization. So, the potential sites of wind generating in our country must be surveyed and analyzed the feasibility of wind energy utilization. In addition to this, the technique of wind energy prediction considered of the topography, surface roughness and obstacle condition must be established for the reliable analysis of wind energy utilization. The contents carried out in this project are shown below, 1. Determining of the measuring sites of wind data - Wyoulryung-ri, Youngrag-ri, Gapa-ri in Cheju Province - Heul-ri, Gangwon Province. 2. Analysis of wind energy at measuring sites The characteristics of wind energy at the measured sites were analysed. It will be continued to measure the wind data by wind data logger. 3. A study on wind energy prediction technique It was studied how to obtain the topographic map data for using WAsP(WIndAtlas Analysis and Application Program). (author). 21 refs., 59 figs., 19 tabs.

  4. Numerical study on aerodynamic damping of floating vertical axis wind turbines

    Science.gov (United States)

    Cheng, Zhengshun; Aagaard Madsen, Helge; Gao, Zhen; Moan, Torgeir

    2016-09-01

    Harvesting offshore wind energy resources using floating vertical axis wind turbines (VAWTs) has attracted an increasing interest in recent years. Due to its potential impact on fatigue damage, the aerodynamic damping should be considered in the preliminary design of a floating VAWT based on the frequency domain method. However, currently the study on aerodynamic damping of floating VAWTs is very limited. Due to the essential difference in aerodynamic load characteristics, the aerodynamic damping of a floating VAWT could be different from that of a floating horizontal axis wind turbine (HAWT). In this study, the aerodynamic damping of floating VAWTs was studied in a fully coupled manner, and its influential factors and its effects on the motions, especially the pitch motion, were demonstrated. Three straight-bladed floating VAWTs with identical solidity and with a blade number varying from two to four were considered. The aerodynamic damping under steady and turbulent wind conditions were estimated using fully coupled aero-hydro-servo-elastic time domain simulations. It is found that the aerodynamic damping ratio of the considered floating VAWTs ranges from 1.8% to 5.3%. Moreover, the aerodynamic damping is almost independent of the rotor azimuth angle, and is to some extent sensitive to the blade number.

  5. Comparative study of the behavior of wind-turbines in a wind farm

    Energy Technology Data Exchange (ETDEWEB)

    Migoya, Emilio; Crespo, Antonio; Garcia, Javier; Manuel, Fernando; Jimenez, Angel [Universidad Politecnica de Madrid (UPM), Madrid (Spain). Departamento de Ingenieria Energetica y Fluidomecanica, Laboratorio de Mecanica de Fluidos; Moreno, Fermin [Comision Nacional de la Energia, Madrid (Spain); Costa, Alexandre [Energia Eolica, Division de Energias Renovables, CIEMAT, Madrid (Spain)

    2007-10-15

    The Sotavento wind farm is an experimental wind farm which has different types of wind turbines. It is located in an area whose topography is moderately complex, and where wake effects can be significant. One of the objectives of Sotavento wind farm is to compare the performances of the different machines; particularly regarding power production, maintenance and failures. However, because of wakes and topography, the different machines are not working under identical conditions. Two linearized codes have been used to estimate topography effects: UPMORO and WAsP. For wind directions in which topography is abrupt, the non-linear flow equations have been solved with the commercial code FLUENT, although the results are only qualitatively used. For wake effects, the UPMPARK code has been applied. As a result, the incident velocity over each wind turbine is obtained, and the power production is estimated by means of the power curve of each machine. Experimental measurements give simultaneously the wind characteristics at the measuring stations, the wind velocity, at the nacelle anemometer, and the power production of each wind turbine. These experimental results are employed to validate the numerical predictions. The main objective of this work is to deduce and validate a relationship between the wind characteristics measured in the anemometers and the wind velocity and the power output in each machine. (author)

  6. Quantifying offshore wind resources from satellite wind maps: Study area the North Sea

    DEFF Research Database (Denmark)

    Hasager, Charlotte Bay; Barthelmie, Rebecca Jane; Christiansen, Merete B.

    2006-01-01

    Offshore wind resources are quantified from satellite synthetic aperture radar (SAR) and satellite scatterometer observations at local and regional scale respectively at the Horns Rev site in Denmark. The method for wind resource estimation from satellite observations interfaces with the wind atlas...... of the Horns Rev wind farm is quantified from satellite SAR images and compared with state-of-the-art wake model results with good agreement. It is a unique method using satellite observations to quantify the spatial extent of the wake behind large offshore wind farms. Copyright © 2006 John Wiley & Sons, Ltd....... analysis and application program (WAsP). An estimate of the wind resource at the new project site at Horns Rev is given based on satellite SAR observations. The comparison of offshore satellite scatterometer winds, global model data and in situ data shows good agreement. Furthermore, the wake effect...

  7. Study of a wind energy conversion system in New Hampshire

    Science.gov (United States)

    Lockwood, J.; Kraft, G.; Pregent, G.; Smukler, L.

    1981-08-01

    Concern over conventional energy costs and supplies is currently strong, particularly in New England region where eighty percent of the total energy is oil based; furthermore, forty percent of this region's total energy is OPEC oil. These figures contrast with national averages of forty-seven and thirteen percent, respectively (1). The quest to develop alternative and renewable energy sources indigenous to New England is understandable in light of these figures. The wind is one such source. The study of wind energy can be divided into three basic areas; these are technical, legal-institutional, and financial. The technical area encompasses collection and analysis of wind data, selection and installation of wind turbines and peripheral equipment, and operation and maintenance. The legal-institutional area encompasses the resolution of such issues as land use policies, power contracts, and state and federal regulations. The financial area encompasses the examination of investment opportunities made available by various site-machine combinations and the selling of such opportunities to the investment community.

  8. A kinetic study of solar wind electrons

    International Nuclear Information System (INIS)

    Lie-Svendsen, Oeystein; Leer, Egil

    1996-01-01

    The evolution of the distribution function for a test population of electrons in an isothermal electron-proton corona has been studied using a Fokker-Planck description. The aim is to investigate whether a suprathermal tail forms due to the energy dependence of the Coulomb cross section. We find that a Maxwellian test population, injected into this background close to the coronal base with a temperature equal to that of the background electrons, maintains its shape throughout the transition from collision-dominated to collisionless flow. No significant suprathermal tail in the electron distribution function is seen in the outer corona

  9. Feasibility study for a standalone solar-wind-based hybrid energy system for application in Ethiopia

    International Nuclear Information System (INIS)

    Bekele, Getachew; Palm, Bjoern

    2010-01-01

    The aim of this paper is to investigate the possibility of supplying electricity from a solar-wind hybrid system to a remotely located model community detached from the main electricity grid in Ethiopia. The wind energy potential of four typical locations has been assessed in a previous article. The solar potential has also been investigated and the results are presented in detail in an accompanying article awaiting publication. For one of the sites, Addis Ababa, the results of the investigation are given here in detail. For the other sites, the results are given as sensitivity diagrams only. Based on the findings of the studies into energy potential, a feasibility study has been carried out on how to supply electricity to a model community of 200 families, which comprises 1000 people in total. The community is equipped with a community school and a health post. The electric load consists of both primary and deferrable types and comprises lighting, water pumps, radio receivers, and some clinical equipment. A software tool, Hybrid Optimization Model for Electric Renewables (HOMER) is used for the analysis. The result of the analysis is a list of feasible power supply systems, sorted according to their net present cost. Furthermore, sensitivity diagrams, showing the influence of wind speeds, PV costs, and diesel prices on the optimum solutions are also provided. (author)

  10. Feasibility study for a standalone solar-wind-based hybrid energy system for application in Ethiopia

    Energy Technology Data Exchange (ETDEWEB)

    Bekele, Getachew; Palm, Bjoern [Department of Energy Technology, KTH, Stockholm (Sweden)

    2010-02-15

    The aim of this paper is to investigate the possibility of supplying electricity from a solar-wind hybrid system to a remotely located model community detached from the main electricity grid in Ethiopia. The wind energy potential of four typical locations has been assessed in a previous article. The solar potential has also been investigated and the results are presented in detail in an accompanying article awaiting publication. For one of the sites, Addis Ababa, the results of the investigation are given here in detail. For the other sites, the results are given as sensitivity diagrams only. Based on the findings of the studies into energy potential, a feasibility study has been carried out on how to supply electricity to a model community of 200 families, which comprises 1000 people in total. The community is equipped with a community school and a health post. The electric load consists of both primary and deferrable types and comprises lighting, water pumps, radio receivers, and some clinical equipment. A software tool, Hybrid Optimization Model for Electric Renewables (HOMER) is used for the analysis. The result of the analysis is a list of feasible power supply systems, sorted according to their net present cost. Furthermore, sensitivity diagrams, showing the influence of wind speeds, PV costs, and diesel prices on the optimum solutions are also provided. (author)

  11. Contribution of large scale coherence to wind turbine power: A large eddy simulation study in periodic wind farms

    Science.gov (United States)

    Chatterjee, Tanmoy; Peet, Yulia T.

    2018-03-01

    Length scales of eddies involved in the power generation of infinite wind farms are studied by analyzing the spectra of the turbulent flux of mean kinetic energy (MKE) from large eddy simulations (LES). Large-scale structures with an order of magnitude bigger than the turbine rotor diameter (D ) are shown to have substantial contribution to wind power. Varying dynamics in the intermediate scales (D -10 D ) are also observed from a parametric study involving interturbine distances and hub height of the turbines. Further insight about the eddies responsible for the power generation have been provided from the scaling analysis of two-dimensional premultiplied spectra of MKE flux. The LES code is developed in a high Reynolds number near-wall modeling framework, using an open-source spectral element code Nek5000, and the wind turbines have been modelled using a state-of-the-art actuator line model. The LES of infinite wind farms have been validated against the statistical results from the previous literature. The study is expected to improve our understanding of the complex multiscale dynamics in the domain of large wind farms and identify the length scales that contribute to the power. This information can be useful for design of wind farm layout and turbine placement that take advantage of the large-scale structures contributing to wind turbine power.

  12. Experimental and numerical study of a 10MW TLP wind turbine in waves and wind

    DEFF Research Database (Denmark)

    Pegalajar Jurado, Antonio Manuel; Hansen, Anders Mandrup; Laugesen, Robert

    2016-01-01

    with the tests by matching key system features, namely the steady thrust curve and the decay tests in water. The calibrated model is used to reproduce the wind-wave climates in the laboratory, including regular and irregular waves, with and without wind. The model predictions are compared to the measured data......This paper presents tests on a 1:60 version of the DTU 10MW wind turbine mounted on a tension leg platform and their numerical reproduction. Both the experimental setup and the numerical model are Froude-scaled, and the dynamic response of the floating wind turbine to wind and waves is compared......, and a good agreement is found for surge and heave, while some discrepancies are observed for pitch, nacelle acceleration and line tension. The addition of wind generally improves the agreement with test results. The aerodynamic damping is identified in both tests and simulations. Finally, the sources...

  13. French offshore wind power - Impact studies: how to make them

    International Nuclear Information System (INIS)

    Rap, C.

    2014-01-01

    The first public inquiries for the installation of wind farms off French coasts will take place in 2015 and impact studies appear to be key elements to back discussions and debates. These studies will have to assess the impact of the wind turbines on different aspects of the natural environment. For the landscape aspect, the visual perception of the wind farm from the coast and coastal villages will have to be studied. As for natural life, the impact on the fish resource will have to be assessed as well as the effects on bird, bat and sea mammal populations. The risk of accident with ships or planes will have to be considered. Some impacts will be positive or negative, permanent or temporary, direct or indirect. The final report will have to propose measures to mitigate negative impacts or even remedial measures if necessary to compensate for them. Impact studies imply to make a preliminary study of the environment prior the installation in order to draw the reference situation. (A.C.)

  14. Mapping Suitable Sites for Setting up Wind Farms: A Case Study of ...

    African Journals Online (AJOL)

    Mapping Suitable Sites for Setting up Wind Farms: A Case Study of Nyanga District. ... Ethiopian Journal of Environmental Studies and Management ... sources and continuous power shortages make wind energy a very attractive alternative to ...

  15. Turbulent Flow Inside and Above a Wind Farm: A Wind-Tunnel Study

    Directory of Open Access Journals (Sweden)

    Leonardo P. Chamorro

    2011-11-01

    Full Text Available Wind-tunnel experiments were carried out to better understand boundary layer effects on the flow pattern inside and above a model wind farm under thermally neutral conditions. Cross-wire anemometry was used to characterize the turbulent flow structure at different locations around a 10 by 3 array of model wind turbines aligned with the mean flow and arranged in two different layouts (inter-turbine separation of 5 and 7 rotor diameters in the direction of the mean flow by 4 rotor diameters in its span. Results suggest that the turbulent flow can be characterized in two broad regions. The first, located below the turbine top tip height, has a direct effect on the performance of the turbines. In that region, the turbulent flow statistics appear to reach equilibrium as close as the third to fourth row of wind turbines for both layouts. In the second region, located right above the first one, the flow adjusts slowly. There, two layers can be identified: an internal boundary layer where the flow is affected by both the incoming wind and the wind turbines, and an equilibrium layer, where the flow is fully adjusted to the wind farm. An adjusted logarithmic velocity distribution is observed in the equilibrium layer starting from the sixth row of wind turbines. The effective surface roughness length induced by the wind farm is found to be higher than that predicted by some existing models. Momentum recovery and turbulence intensity are shown to be affected by the wind farm layout. Power spectra show that the signature of the tip vortices, in both streamwise and vertical velocity components, is highly affected by both the relative location in the wind farm and the wind farm layout.

  16. Physics-based Tests to Identify the Accuracy of Solar Wind Ion Measurements: A Case Study with the Wind Faraday Cups

    Science.gov (United States)

    Kasper, J. C.; Lazarus, A. J.; Steinberg, J. T.; Ogilvie, K. W.; Szabo, A.

    2006-01-01

    We present techniques for comparing measurements of velocity, temperature, and density with constraints imposed by the plasma physics of magnetized bi-Maxwellian ions. Deviations from these physics-based constraints are interpreted as arising from measurement errors. Two million ion spectra from the Solar Wind Experiment Faraday Cup instruments on the Wind spacecraft are used as a case study. The accuracy of velocity measurements is determined by the fact that differential flow between hydrogen and helium should be aligned with the ambient magnetic field. Modeling the breakdown of field alignment suggests velocity uncertainties are less than 0.16% in magnitude and 3deg in direction. Temperature uncertainty is found by examining the distribution of observed temperature anisotropies in high-beta solar wind intervals where the firehose, mirror, and cyclotron microinstabilities should drive the distribution to isotropy. The presence of a finite anisotropy at high beta suggests overall temperature uncertainties of 8%. Hydrogen and helium number densities are compared with the electron density inferred from observations of the local electron plasma frequency as a function of solar wind speed and year. We find that after accounting for the contribution of minor ions, the results are consistent with a systematic offset between the two instruments of 34%. The temperature and density methods are sensitive to non-Maxwellian features such as heat flux and proton beams and as a result are more suited to slow solar wind where these features are rare. These procedures are of general use in identifying the accuracy of observations from any solar wind ion instrument.

  17. Benefits for wind energy in electricity markets from using short term wind power prediction tools: a simulation study

    International Nuclear Information System (INIS)

    Usaola, J.; Ravelo, O.; Gonzalez, G.; Soto, F.; Davila, M.C.; Diaz-Guerra, B.

    2004-01-01

    One of the characteristics of wind energy, from the grid point of view, is its non-dispatchability, i.e. generation cannot be ordered, hence integration in electrical networks may be difficult. Short-term wind power prediction-tools could make this integration easier, either by their use by the grid System Operator, or by promoting the participation of wind farms in the electricity markets and using prediction tools to make their bids in the market. In this paper, the importance of a short-term wind power-prediction tool for the participation of wind energy systems in electricity markets is studied. Simulations, according to the current Spanish market rules, have been performed to the production of different wind farms, with different degrees of accuracy in the prediction tool. It may be concluded that income from participation in electricity markets is increased using a short-term wind power prediction-tool of average accuracy. This both marginally increases income and also reduces the impact on system operation with the improved forecasts. (author)

  18. Seawater pumped storage systems and offshore wind parks in islands with low onshore wind potential. A fundamental case study

    International Nuclear Information System (INIS)

    Katsaprakakis, Dimitris Al.; Christakis, Dimitris G.

    2014-01-01

    The scope of this article is to investigate the effects of introducing a WP-PSS (Wind Powered Pumped Storage System) in isolated electricity systems assuming unfavourable conditions such as low onshore wind potential and low PSS head height. These disadvantages can be compensated with the installation of offshore wind parks, larger reservoirs and double penstocks to allow simultaneous water fall and pumping using pipes of the greatest diameter that are currently commercially available. With the above modifications, the energy efficiency of the WP-PSS improves while the installation costs rise. A new operation algorithm for the WP-PSS is created to fully utilize the capacity of the double penstock and ultimately maximise wind energy penetration. A case study for a WP-PSS on the island of Rhodes is presented in this paper. Despite unfavourable conditions, the WP-PSS model leads to the following results: • Annual wind energy penetration exceeds 50% of the annual electricity consumption. • The WP-PSS exhibits attractive financial induces without including any subsidies. The WP-PSS presented in this paper proved to be technically and economically feasible and revealed that WP-PSSs are a guaranteed choice for large scale penetration of R.E.S. in electrical systems. - Highlights: • Offshore wind parks (WPs) and seawater PSS can guarantee power production in autonomous systems. • The examined system is proved technically and economically feasible under unfavourable conditions. • A new operational algorithm is developed to maximise the wind energy penetration. • The annual wind energy penetration exceeds 50%. The economic indexes are acceptable. • The WP-PSS is a guaranteed choice for wind energy penetration maximisation

  19. Cherokee Wind Energy Development - Feasibility and Pre-Construction Studies

    Energy Technology Data Exchange (ETDEWEB)

    McMillan, Andy [Cherokee Nation Businesses, LLC, Catoosa, OK (United States)

    2017-06-30

    Cherokee Nation Businesses (CNB) received a grant from the US Department of Energy to explore feasibility and pursue development of a wind power generation facility on Cherokee land in north-central Oklahoma. This project followed several years of initial study exploring the possibility of commercial-scale wind power generation on primarily agricultural land owned by the Cherokee Nation. This project produced detailed analysis of the legal, financial and market viability of such generation facilities, and encompassed a full technical evaluation of the engineering, environmental, and geotechnical aspects of installing this capacity. During the course of this project, information gleaned from this exploration changed CNB’s thinking about the best course of action for Cherokee participation in the development, eventually moving away from an equity-owner model and towards utilization of the land asset as a resource while mitigating Cherokee financial and operational risk.

  20. Sensor comparison study for load alleviating wind turbine pitch control

    DEFF Research Database (Denmark)

    Kragh, Knud Abildgaard; Hansen, Morten Hartvig; Henriksen, Lars Christian

    2014-01-01

    As the size of wind turbines increases, the load alleviating capabilities of the turbine controller are becoming increasingly important. Load alleviating control schemes have traditionally been based on feedback from load sensor; however, recent developments of measurement technologies have enabled...... control on the basis of preview measurements of the inflow acquired using, e.g., light detection and ranging. The potential of alleviating load variations that are caused by mean wind speed changes through feed-forward control have been demonstrated through both experiments and simulations in several...... studies, whereas the potential of preview control for alleviating the load variations caused by azimuth dependent inflow variations is less described. Individual or cyclic pitch is required to alleviate azimuth dependent load variations and is traditionally applied through feedback control of the blade...

  1. Code of Conduct for wind-power projects - Feasibility study

    International Nuclear Information System (INIS)

    Strub, P.; Ziegler, Ch.

    2009-02-01

    This final report deals with the results of a feasibility study concerning the development of a Code of Conduct for wind-power projects. The aim is to strengthen the acceptance of wind-power by the general public. The necessity of new, voluntary market instruments is discussed. The urgency of development in this area is quoted as being high, and the authors consider the feasibility of the definition of a code of conduct as being proven. The code of conduct can, according to the authors, be of use at various levels but primarily in project development. Further free-enterprise instruments are also suggested that should help support socially compatible and successful market development. It is noted that the predominant portion of those questioned are prepared to co-operate in further work on the subject

  2. A study of offshore wind HVDC system stability and control

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Hanchao; Sun, Jian [Rensselaer Polytechnic Institute, Troy, NY (United States). Dept. of Electrical, Computer and Systems Engineering

    2011-07-01

    This work is concerned with the stability and control of ac power collection buses in offshore wind farms with high-voltage dc (HVDC) transmission connection to onshore power grid. The focus of the work is high-frequency interactions among the wind turbines, the ac collection bus and the filters, as well as the HVDC rectifier. Both voltage-source converter and line-commutated converter based HVDC systems are considered. To study high-frequency stability, particularly harmonic resonance in the ac bus, small-signal impedance models are developed for the wind inverters and the HVDC rectifier by using harmonic linearization techniques. An impedance-based stability criterion is applied to assess system stability in both positive- and negative-sequence domain. Small-signal stability conditions and requirements are developed from analytical impedance models. Detailed system-level simulation is used to validated the small-signal analysis. The goal of the study is to develop system design and control techniques that minimize the cost of the offshore infrastructure while guaranteeing system stability and power quality. (orig.)

  3. A study of wind hydrogen production of systems for Malaysia

    International Nuclear Information System (INIS)

    Ibrahim, M.Z.; Kamaruzzaman Sopian; Wan Ramli Wan Daud; Othman, M.Y.; Baharuddin Yatim; Veziroglu, T.N.

    2006-01-01

    Recently, Malaysia is looking into the potential of using hydrogen as future fuel. By recognizing the potential of hydrogen fuel, the government had channeled a big amount of money in funds to related organizations to embark on hydrogen research and development programmed. The availability of indigenous renewable resources, high trade opportunities, excellent research capabilities and current progress in hydrogen research at the university are some major advantages for the country to attract government and industry investment in hydrogen. It is envisaged that overall energy demand in Malaysia as stated in the Eighth Malaysia Plan (EMP) report will increase by about 7.8 percent per annum in this decade at the present economic growth. Considering the vast potential inherent in renewable energy (RE), it could be a significant contributor to the national energy supply. Malaysia had been blessed with abundant and varied resources of energy, nevertheless, concerted efforts should be undertaken to ensure that the development of energy resources would continue to contribute to the nation's economic expansion. In this regard, an initial study has been carried out to see the available potential of wind energy towards the hydrogen production, that could be utilized in various applications particularly in Malaysian climate condition via a computer simulation (HYDROGEMS), which built for TRNSYS (a transient system simulation program) version 15. The system simulated in this study consist of one unit (1 kW) wind turbine, an electrolyze (1 kW), a hydrogen (H 2 ) storage tank, and a power conditioning system. A month hourly data of highest wind speed is obtained from the local weather station that is at Kuala Terengganu Air Port located at 5''o 23'' latitude (N) and 103''o 06'' Longitude (E). The results show, wind energy in Malaysian Climate has a potential to generate hydrogen with the minimum rate approximately 9 m 3 /hr and storage capacity of 60 Nm 3 , State of Charge (SOC

  4. A study of the solar wind deceleration in the Earth's foreshock region

    Science.gov (United States)

    Zhang, T.-L.; Schwingenschuh, K.; Russell, C. T.

    1995-01-01

    Previous observations have shown that the solar wind is decelerated and deflected in the earth's upstream region populated by long-period waves. This deceleration is corelated with the 'diffuse' but not with the 'reflected' ion population. The speed of the solar wind may decrease tens of km/s in the foreshock region. The solar wind dynamic pressure exerted on the magnetopause may vary due to the fluctuation of the solar wind speed and density in the foreshock region. In this study, we examine this solar wind deceleration and determine how the solar wind deceleration varies in the foreshock region.

  5. Wind Speed Pattern in Nigeria (A Case Study of Some Coastal and ...

    African Journals Online (AJOL)

    ADOWIE PERE

    Department of Physics and Solar Energy, Bowen University Iwo, Osun State, Nigeria ... ABSTRACT: In this study, wind speeds were analysed using the daily wind data obtained from Nigeria ..... Selected sites from Three Geopolitical Zones in.

  6. Voltage sensitivity based reactive power control on VSC-HVDC in a wind farm connected hybrid multi-infeed HVDC system

    DEFF Research Database (Denmark)

    Liu, Yan; Chen, Zhe

    2013-01-01

    With increasing application of both Line Commutated Converter based High Voltage Direct Current (LCC-HVDC) systems and Voltage Source Converter based HVDC (VSC-HVDC) links, a new type of system structure named Hybrid Multi-Infeed HVDC (HMIDC) system is formed in the modern power systems. This paper...... presents the operation and control method of the wind farm connected HMIDC system. The wind power fluctuation takes large influence to the system voltages. In order to reduce the voltage fluctuation of LCC-HVDC infeed bus caused by the wind power variation, a voltage sensitivity-based reactive power...

  7. Sensitivity of Turbine-Height Wind Speeds to Parameters in Planetary Boundary-Layer and Surface-Layer Schemes in the Weather Research and Forecasting Model

    Science.gov (United States)

    Yang, Ben; Qian, Yun; Berg, Larry K.; Ma, Po-Lun; Wharton, Sonia; Bulaevskaya, Vera; Yan, Huiping; Hou, Zhangshuan; Shaw, William J.

    2017-01-01

    We evaluate the sensitivity of simulated turbine-height wind speeds to 26 parameters within the Mellor-Yamada-Nakanishi-Niino (MYNN) planetary boundary-layer scheme and MM5 surface-layer scheme of the Weather Research and Forecasting model over an area of complex terrain. An efficient sampling algorithm and generalized linear model are used to explore the multiple-dimensional parameter space and quantify the parametric sensitivity of simulated turbine-height wind speeds. The results indicate that most of the variability in the ensemble simulations is due to parameters related to the dissipation of turbulent kinetic energy (TKE), Prandtl number, turbulent length scales, surface roughness, and the von Kármán constant. The parameter associated with the TKE dissipation rate is found to be most important, and a larger dissipation rate produces larger hub-height wind speeds. A larger Prandtl number results in smaller nighttime wind speeds. Increasing surface roughness reduces the frequencies of both extremely weak and strong airflows, implying a reduction in the variability of wind speed. All of the above parameters significantly affect the vertical profiles of wind speed and the magnitude of wind shear. The relative contributions of individual parameters are found to be dependent on both the terrain slope and atmospheric stability.

  8. Study on optimal design of wind turbine blade airfoil and its application

    International Nuclear Information System (INIS)

    Sun, Min Young; Kim, Dong Yong; Lim, Jae Kyoo

    2012-01-01

    This study was carried out with two goals. One was the development of a model of a wind turbine blade airfoil and the other was the application of the folding blade. In general, in large sized (MW) wind turbines, damage is prevented in small wind turbines since equipment costs and maintenance costs are high, and therefore, the blade will cause serious damage. The wind turbine proposed in this study does not require maintenance, and the blades do not break during high winds because they are folded in accordance with changes in the wind speed. But generators are not cut out, while maintaining a constant angle will continue to produce. The focus of this study, the wind turbine is continued by folding blade system in strong winds and gusts without stopping production

  9. Study on optimal design of wind turbine blade airfoil and its application

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Min Young; Kim, Dong Yong; Lim, Jae Kyoo [Chonbuk Nat' l Univ., Jeonju (Korea, Republic of)

    2012-05-15

    This study was carried out with two goals. One was the development of a model of a wind turbine blade airfoil and the other was the application of the folding blade. In general, in large sized (MW) wind turbines, damage is prevented in small wind turbines since equipment costs and maintenance costs are high, and therefore, the blade will cause serious damage. The wind turbine proposed in this study does not require maintenance, and the blades do not break during high winds because they are folded in accordance with changes in the wind speed. But generators are not cut out, while maintaining a constant angle will continue to produce. The focus of this study, the wind turbine is continued by folding blade system in strong winds and gusts without stopping production.

  10. Effect of Wind Turbine Noise on Workers' Sleep Disorder: A Case Study of Manjil Wind Farm in Northern Iran

    Science.gov (United States)

    Abbasi, Milad; Monnazzam, Mohammad Reza; Zakerian, Sayedabbolfazl; Yousefzadeh, Arsalan

    2015-04-01

    Noise from wind turbines is one of the most important factors affecting the health, welfare, and human sleep. This research was carried out to study the effect of wind turbine noise on workers' sleep disorder. For this, Manjil Wind Farm, because of the greater number of staff and turbines than other wind farms in Iran, was chosen as case study. A total number of 53 participants took part in this survey. They were classified into three groups of mechanics, security, and official. In this study, daytime sleepiness data of workers were gathered using Epworth Sleepiness Scales (ESS) was used to determine the level of daytime sleepiness among the workers. The 8-h equivalent sound level (LAeq,8h) was measured to determine the individuals' exposure at each occupational group. Finally, the effect of sound, age, and workers' experience on individuals' sleep disorder was analyzed through multiple regression analysis in the R software. The results showed that there was a positive and significant relationship between age, workers' experience, equivalent sound level, and the level of sleep disorder. When age is constant, sleep disorder will increase by 26% as per each 1 dB increase in equivalent sound level. In situations where equivalent sound level is constant, an increase of 17% in sleep disorder is occurred as per each year of work experience. Because of the difference in sound exposure in different occupational groups. The effect of noise in repairing group was about 6.5 times of official group and also 3.4 times of the security group. Sleep disorder effect caused by wind turbine noise in the security group is almost two times more than the official group. Unlike most studies on wind turbine noise that address the sleep disorder among inhabitants nearby wind farms, this study, for the first time in the world, examines the impact of wind turbine noise on sleep disorder of workers who are more closer to wind turbines and exposed to higher levels of noise. So despite all the

  11. Offshore and onshore wind turbine wake meandering studied in an ABL wind tunnel

    DEFF Research Database (Denmark)

    Barlas, Emre; Buckingham, Sophia; Glabeke, Gertjan

    2015-01-01

    Scaled wind turbine models have been installed in the VKI L1-B atmospheric boundary layer wind tunnel at offshore and onshore conditions. Time-resolved measurements were carried out with three component hot wire anemometry and stereo-PIV in the middle vertical plane of the wake up to eleven turbine...... diameter downstream. The results show an earlier wake recovery for the onshore case. The effect of inflow conditions and the wind turbine’s working conditions on wake meandering was investigated. Wake meandering was detected by hot wire anemometry through a low frequency peak in the turbulent power...

  12. Pressure-Sensitive Paint Measurements on the NASA Common Research Model in the NASA 11-ft Transonic Wind Tunnel

    Science.gov (United States)

    Bell, James H.

    2011-01-01

    The luminescence lifetime technique was used to make pressure-sensitive paint (PSP) measurements on a 2.7% Common Research Model in the NASA Ames 11ft Transonic Wind Tunnel. PSP data were obtained on the upper and lower surfaces of the wing and horizontal tail, as well as one side of the fuselage. Data were taken for several model attitudes of interest at Mach numbers between 0.70 and 0.87. Image data were mapped onto a three-dimensional surface grid suitable both for comparison with CFD and for integration of pressures to determine loads. Luminescence lifetime measurements were made using strobed LED (light-emitting diode) lamps to illuminate the PSP and fast-framing interline transfer cameras to acquire the PSP emission.

  13. NREL Studies Wind Farm Aerodynamics to Improve Siting (Fact Sheet)

    Energy Technology Data Exchange (ETDEWEB)

    2012-04-01

    NREL researchers have used high-tech instruments and high-performance computing to understand atmospheric turbulence and turbine wake behavior in order to improve wind turbine design and siting within wind farms.

  14. Environmental impacts of wind power. Case study of wind turbines in living environment; Vindkraftens Miljoepaaverkan. Fallstudie av vindkraftverk i boendemiljoe

    Energy Technology Data Exchange (ETDEWEB)

    Widing, Angelica; Britse, Gunilla; Wizelius, Tore [Gotland Univ., Visby (Sweden). Windpower information centre

    2006-06-15

    The aim of this project has been to get more knowledge about the impact of noise, shadows and on the view of the landscape from wind turbines. Further to be able to increase the reliability and relevance of the methods used to calculate and evaluate nuisances from wind turbines in applications for wind power development. We have also tried to find other factors that can play a role for the evaluation of wind turbines, if they will be considered as a nuisance or not. The research has focused on a critical review of the methods and regulations that are used in Sweden and other countries, and case studies to find out how people living neighbors with wind turbines will be affected by noise, rotating shadows, visual intrusion and other factors. This report includes the case studies of wind turbine areas at Gotland. Three different areas on the island Gotland in the Baltic Sea, with wind turbines in the close neighborhood, were chosen for case studies: Naer, Klintehamn, Naesudden. In these places only persons who live close to wind turbines have been interviewed; in Nar all who live within 1100 meters from two large wind turbines, in Klintehamn a sample of those who live ESE of the turbines and get shadow flicker from them during sunset, and on Naesudden those households that live in the middle of a large wind farm with 81 turbines. In total 94 persons in 69 households have been interviewed. The acceptance of wind power among people living as close neighbors is quite high. However, the nuisance and annoyance can be reduced further, if the recommended values for noise immission etc are applied correctly. To do that the ability of project developers and authorities that grant permissions to evaluate the calculated immission has to be raised, since specialist competence and experience is necessary to do predictions of actual immission from the models used for calculations. The recommended minimum distances between wind turbines and houses that some communities have

  15. Sensitivity studies for supernovae type Ia

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, Thien Tam; Goebel, Kathrin; Reifarth, Rene [Goethe University Frankfurt am Main (Germany); Calder, Alan [SUNY - Department of Physics and Astronomy, New York (United States); Pignatari, Marco [Konkoly Observatory of the Hungarian Academy of Sciences (Hungary); Townsley, Dean [The University of Alabama (United States); Travaglio, Claudia [INAF - Astrophysical Observatory, Turin (Italy); Collaboration: NuGrid collaboration

    2016-07-01

    The NuGrid research platform provides a simulation framework to study the nucleosynthesis in multi-dimensional Supernovae Type Ia models. We use a large network of over 5,000 isotopes and more than 60,000 reactions. The nucleosynthesis is investigated in post-processing simulations with temperature and density profiles, initial abundance distributions and a set of reaction rates as input. The sensitivity of the isotopic abundances to α-, proton-, and neutron-capture reaction, their inverse reactions, as well as fusion reactions were investigated. First results have been achieved for different mass coordinates of the exploding star.

  16. Wind turbine power coefficient estimation by soft computing methodologies: Comparative study

    International Nuclear Information System (INIS)

    Shamshirband, Shahaboddin; Petković, Dalibor; Saboohi, Hadi; Anuar, Nor Badrul; Inayat, Irum; Akib, Shatirah; Ćojbašić, Žarko; Nikolić, Vlastimir; Mat Kiah, Miss Laiha; Gani, Abdullah

    2014-01-01

    Highlights: • Variable speed operation of wind turbine to increase power generation. • Changeability and fluctuation of wind has to be accounted. • To build an effective prediction model of wind turbine power coefficient. • The impact of the variation in the blade pitch angle and tip speed ratio. • Support vector regression methodology application as predictive methodology. - Abstract: Wind energy has become a large contender of traditional fossil fuel energy, particularly with the successful operation of multi-megawatt sized wind turbines. However, reasonable wind speed is not adequately sustainable everywhere to build an economical wind farm. In wind energy conversion systems, one of the operational problems is the changeability and fluctuation of wind. In most cases, wind speed can vacillate rapidly. Hence, quality of produced energy becomes an important problem in wind energy conversion plants. Several control techniques have been applied to improve the quality of power generated from wind turbines. In this study, the polynomial and radial basis function (RBF) are applied as the kernel function of support vector regression (SVR) to estimate optimal power coefficient value of the wind turbines. Instead of minimizing the observed training error, SVR p oly and SVR r bf attempt to minimize the generalization error bound so as to achieve generalized performance. The experimental results show that an improvement in predictive accuracy and capability of generalization can be achieved by the SVR approach in compare to other soft computing methodologies

  17. Feasibility study of offshore wind turbine installation in Iran compared with the world

    Energy Technology Data Exchange (ETDEWEB)

    Mostafaeipour, Ali [Industrial Engineering Department, Yazd University, Yazd (Iran)

    2010-09-15

    Renewable energies have potential for supplying of relatively clean and mostly local energy. Wind energy generation is expected to increase in the near future and has experienced dramatic growth over the past decade in many countries. Offshore winds are generally stronger and more constant than onshore winds in many areas. The economic feasibility for utilization of offshore wind energy depends on the favorable wind conditions in the area. The present paper analyses offshore wind speed in global scale and also studies feasibility of introducing this technology for harnessing wind in Persian Gulf, Caspian Sea, Urmia Lake and Gulf of Oman. Wind speed data were collected from different sources. The ocean surface winds at a 10 m height from satellite passes as processed by NOAA/NESDIS, from near real-time data collected by NASA/JPL's Sea Winds Scatterometer aboard the QuikSCAT. Development of renewable energy is one of priority research goals in Iran. There are many installed wind turbines in suitable regions like Manjil and Binalood, but there has not been any offshore wind installation yet in Iran. It is suggested that policy makers to invest and pay more attentions toward harnessing renewable energy sources like offshore wind in Persian Gulf and Gulf of Oman in southern parts of Iran. (author)

  18. Wind tunnel study of helical and straight-bladed vertical-axis wind turbine wakes

    Science.gov (United States)

    Bagheri, Maryam; Araya, Daniel

    2017-11-01

    It is hypothesized that blade curvature can serve as a passive means to control fluid entrainment and wake recovery in vertical-axis wind turbine (VAWT) arrays. We test this experimentally in a wind tunnel using two different VAWT configurations, one with straight blades and another with helical blades, keeping all other experimental parameters fixed. A small-scale, commercially available VAWT (15W max power) is used as the baseline wind tunnel model in each case. The commercial VAWT blades are replaced with either straight or helical blades that are 3D-printed extrusions of the same airfoil cross-section. Results from smoke flow visualization, three-component wake velocity measurements, and turbine power data are presented. These results give insight into the potential use of VAWTs with curved blades in utility-scale wind farms.

  19. Shadowing effects of offshore wind farms - an idealised mesoscale model study

    DEFF Research Database (Denmark)

    Volker, Patrick; Badger, Jake; Hahmann, Andrea N.

    The study of wind farm (WF) interaction is expected to gain importance, since the offshore wind farm density will increase especially in the North Sea in the near future. We present preliminary results of wind farm interaction simulated by mesoscale models. We use the Explicit Wake Parametrisatio...

  20. Deterministic and Stochastic Study of Wind Farm Harmonic Currents

    DEFF Research Database (Denmark)

    Sainz, Luis; Mesas, Juan Jose; Teodorescu, Remus

    2010-01-01

    Wind farm harmonic emissions are a well-known power quality problem, but little data based on actual wind farm measurements are available in literature. In this paper, harmonic emissions of an 18 MW wind farm are investigated using extensive measurements, and the deterministic and stochastic char...

  1. Coastal wind study based on Sentinel-1 and ground-based scanning lidar

    DEFF Research Database (Denmark)

    Hasager, Charlotte Bay; Badger, Merete; Pena Diaz, Alfredo

    Winds in the coastal zone have importance for near-shore wind farm planning. Recently the Danish Energy Agency gave new options for placing offshore wind farms much closer to the coastlines than previously. The new tender areas are located from 3 to 8 km from the coast. Ground-based scanning lidar...... located on land can partly cover this area out to around 15 km. In order to improve wind farm planning for near-shore coastal areas, the project‘Reducing the Uncertainty of Near-shore Energy estimates from meso- and micro-scale wind models’ (RUNE) is established. The measurement campaign starts October....... The various observation types have advantages and limitations; one advantage of both the Sentinel-1 and the scanning lidar is that they both observe wind fields covering a large area and so can be combined for studying the spatial variability of winds. Sentinel-1 are being processed near-real-time at DTU Wind...

  2. Societal acceptance of wind farms: Analysis of four common themes across Australian case studies

    International Nuclear Information System (INIS)

    Hall, N.; Ashworth, P.; Devine-Wright, P.

    2013-01-01

    Australia's renewable energy target (RET) seeks to provide 20 per cent of Australia's electricity generation from renewable energy sources by 2020. As wind power is relatively advanced, it was anticipated that wind power will contribute a major component of the early target. However, high levels of societal resistance to wind farms, combined with new regulatory policies, indicate the RET may not be dominated by wind power. This research involved an examination of seven case studies around wind farm deployment. Qualitative interviews were the primary data for the case studies and analysed using methods informed by grounded theory. Despite the diversity of stakeholder views, the qualitative analysis identified strong community support for wind farms but four common themes emerged that influence this societal acceptance of wind farms in Australia: trust, distributional justice, procedural justice and place attachment. Without addressing these factors through integration into policy development and engagement approaches, wind energy is unlikely to provide the early and majority of new renewable energy. Similar international experiences are incorporated in the discussion of the Australian wind industry's societal acceptance. - Highlights: ► Seven case studies of wind farms in Australia are described. ► Acceptance affects whether wind significantly contributes to the Aust. RE target. ► Four themes were identified regarding societal acceptance of Australian wind farms. ► Four themes are trust, distributional and procedural justice, and place attachment. ► International similarities to the Australian experience are provided

  3. Experimental study of dynamic stall on Darrieus wind turbine blades

    Science.gov (United States)

    Brochier, G.; Fraunie, P.; Beguier, C.; Paraschivoiu, I.

    1985-12-01

    An experimental study of periodic vortex phenomena was performed on a model of a two straight-bladed Darrieus wind turbine under controlled-rotation conditions in the IMST water tunnel. The main focus of interest was the tip-speed ratios at which dynamic stall appears. Observations of this phenomenon from dye emission and the formation of hydrogen bubbles were made in the form of photographs, film and video recordings. Velocity measurements were obtained using the Laser-Doppler Velocimeter and components of velocity fluctuations could be determined quantitatively.

  4. A brief comparative study of the wind and nuclear energy

    International Nuclear Information System (INIS)

    Flores, Tarcisio Santos

    2015-01-01

    It is apparent the human need to use electricity in the current globalized world. And along with the social and industrial and beyond the everyday comfort evolution came the abuse of power. Aware that Brazil is used as an energy source originating from hydroelectric and that it does not include all domestic demand, should be studied energy sources that can assist it. Two clean and cheap energy alternatives which can contribute to reducing the environmental impacts such as global warming and water shortages are wind and nuclear energy. Which again, exhibit ideal characteristics to serve as alternative sources for electricity production, mainly in the dry season. (author)

  5. Modeling of wind turbines for power system studies

    Energy Technology Data Exchange (ETDEWEB)

    Petru, T.

    2001-05-01

    When wind turbines are installed into the electric grid, the power quality is affected. Today, strict installation recommendations often prevail due to a lack of knowledge on this subject. Consequently, it is important to predict the impact of wind turbines on the electric grid before the turbines are installed. The thesis describes relevant power quality issues, discusses different configurations of wind turbines with respect to power quality and draw requirements regarding wind turbine modeling. A model of a stall-regulated, fixed-speed wind turbine system is introduced and its power quality impact on the electric grid is evaluated. The model is verified with field measurements.

  6. An appraisal of wind speed distribution prediction by soft computing methodologies: A comparative study

    International Nuclear Information System (INIS)

    Petković, Dalibor; Shamshirband, Shahaboddin; Anuar, Nor Badrul; Saboohi, Hadi; Abdul Wahab, Ainuddin Wahid; Protić, Milan; Zalnezhad, Erfan; Mirhashemi, Seyed Mohammad Amin

    2014-01-01

    Highlights: • Probabilistic distribution functions of wind speed. • Two parameter Weibull probability distribution. • To build an effective prediction model of distribution of wind speed. • Support vector regression application as probability function for wind speed. - Abstract: The probabilistic distribution of wind speed is among the more significant wind characteristics in examining wind energy potential and the performance of wind energy conversion systems. When the wind speed probability distribution is known, the wind energy distribution can be easily obtained. Therefore, the probability distribution of wind speed is a very important piece of information required in assessing wind energy potential. For this reason, a large number of studies have been established concerning the use of a variety of probability density functions to describe wind speed frequency distributions. Although the two-parameter Weibull distribution comprises a widely used and accepted method, solving the function is very challenging. In this study, the polynomial and radial basis functions (RBF) are applied as the kernel function of support vector regression (SVR) to estimate two parameters of the Weibull distribution function according to previously established analytical methods. Rather than minimizing the observed training error, SVR p oly and SVR r bf attempt to minimize the generalization error bound, so as to achieve generalized performance. According to the experimental results, enhanced predictive accuracy and capability of generalization can be achieved using the SVR approach compared to other soft computing methodologies

  7. Sensitivity of Key Parameters in Aerodynamic Wind Turbine Rotor Design on Power and Energy Performance

    International Nuclear Information System (INIS)

    Bak, Christian

    2007-01-01

    In this paper the influence of different key parameters in aerodynamic wind turbine rotor design on the power efficiency, C p , and energy production has been investigated. The work was divided into an analysis of 2D airfoils/blade sections and of entire rotors. In the analysis of the 2D airfoils it was seen that there was a maximum of the local C p for airfoils with finite maximum C l /C d values. The local speed ratio should be between 2.4 and 3.8 for airfoils with maximum c l /c d between 50 and 200, respectively, to obtain maximum local C p . Also, the investigation showed that Re had a significant impact on CP and especially for Re p for rotors was made with three blades and showed that with the assumption of constant maximum c l /c d along the entire blade, the design tip speed ratio changed from X=6 to X=12 for c l /cd=50 and c l /c d =200, respectively, with corresponding values of maximum c p of 0.46 and 0.525. An analysis of existing rotors re-designed with new airfoils but maintaining the absolute thickness distribution to maintain the stiffness showed that big rotors are more aerodynamic efficient than small rotors caused by higher Re. It also showed that the design tip speed ratio was very dependent on the rotor size and on the assumptions of the airfoil flow being fully turbulent (contaminated airfoil) or free transitional (clean airfoil). The investigations showed that rotors with diameter D=1.75m, should be designed for X around 5.5, whereas rotors with diameter D=126m, should be designed for Xbetween 6.5 and 8.5, depending on the airfoil performance

  8. The necessary distance between large wind farms offshore - study

    DEFF Research Database (Denmark)

    Frandsen, S.; Barthelmie, R.J.; Pryor, S.C.

    2005-01-01

    the new Storpark Analytical Model has been developed and evaluated. As it is often the need for offshore wind farms, the model handles a regular array-geometry with straight rows of wind turbines and equidistantspacing between units in each row and equidistant spacing between rows. Firstly, the case...... with the flow direction being parallel to rows in a rectangular geometry is considered by defining three flow regimes. Secondly, when the flow is not in line withthe main rows, solutions are found for the patterns of wind turbine units emerging corresponding to each wind direction. The model complex......A review of state of the art wake and boundary layer wind farms was conducted. The predictions made for wind recovery distances (that might be used to estimate optimal placing of neighbouring wind farms) range between 2 and 14 km. In order to model thelink between wakes and the boundary layer...

  9. Overview of the New England wind integration. Study and selected results

    Energy Technology Data Exchange (ETDEWEB)

    Norden, John R.; Henson, William L.W. [ISO New England, Holyoke, MA (United States)

    2010-07-01

    ISO New England commissioned a comprehensive wind integration study to be completed in the early fall of 2010: the New England Wind Integration Study (NEWIS). The NEWIS assesses the efects of scenarios that encompass a range of wind-power penetrations in New England using statistical and simulation analysis including the development of a mesoscale wind-to-power model for the New England and Maritime wind resources areas. It also determines the impacts of integrating increasing amounts of wind generation resources for New England, as well as, the measures that may be available to the ISO for responding to any challenges while enabling the integration of wind-power. This paper provides an overview of the study then focuses on selected near final results, particularly with regard to the varying capacity factor, capacity value and siting that were determined as part of the study. The full results of the NEWIS will be released in the fall of 2010. (orig.)

  10. WindPACT Turbine Rotor Design Study: June 2000--June 2002 (Revised)

    Energy Technology Data Exchange (ETDEWEB)

    Malcolm, D. J.; Hansen, A. C.

    2006-04-01

    This report presents the results of the turbine rotor study completed by Global Energy Concepts (GEC) as part of the U.S. Department of Energy's WindPACT (Wind Partnership for Advanced Component Technologies) project. The purpose of the WindPACT project is to identify technology improvements that will enable the cost of energy from wind turbines to fall to a target of 3.0 cents/kilowatt-hour in low wind speed sites. The study focused on different rotor configurations and the effect of scale on those rotors.

  11. Fermeuse wind power project Newfoundland : noise and visual analysis studies

    Energy Technology Data Exchange (ETDEWEB)

    Henn, P.; Turgeon, J.; Heraud, P.; Belanger, S.; Dakousian, S.; Lamontagne, C.; Soares, D. [Helimax Energy Inc., Montreal, PQ (Canada); Basil, C.; Boulianne, S.; Salacup, S.; Thompson, C. [Skypower, Toronto, ON (Canada)

    2008-03-15

    This paper discussed the noise and visual analyses used to assess the potential impacts of a wind energy project on the east coast of the Avalon Peninsula near St. John's, Newfoundland. The proposed farm will be located approximately 1 km away from the town of Fermeuse, and will have an installed capacity of 27 MW from 9 turbines. The paper provided details of the consultation process conducted to determine acceptable distance and site locations for the wind turbines from the community. Stakeholders were identified during meetings, events, and discussions with local authorities. Consultations were also held with government agencies and municipal councils. A baseline acoustic environment study was conducted, and details of anticipated environmental impacts during the project's construction, operation, and decommissioning phases were presented. The visual analysis study was divided into the following landscape units: town, shoreline, forest, open land and lacustrine landscapes. The effect of the turbines on the landscapes were assessed from different viewpoints using visual simulation programs. The study showed that the visual effects of the project are not considered as significant because of the low number of turbines. It was concluded that the effect of construction on ambient noise levels is of low concern as all permanent dwellings are located at least 1 km away from the turbines. 2 refs., 4 tabs., 4 figs.

  12. Wind Energy Study and Energy Cost of Wind Electricity Generation in Nigeria: Past and Recent Results and a Case Study for South West Nigeria

    Directory of Open Access Journals (Sweden)

    Oluseyi O. Ajayi

    2014-12-01

    Full Text Available The study assessed the wind energy potential of ten selected sites in the south western region of Nigeria and carried out a cost benefit analysis of wind power generation at those sites. Twenty four years’ (1987 to 2010 wind speed data at 10 m height obtained from the Nigerian meteorological agency were employed to classify the sites wind profiles for electricity generation. The energy cost analysis of generating wind electricity from the sites was also carried out. The outcome showed that sites in Lagos and Oyo States were adequately suited for large scale generation with average wind speeds ranged between 2.9 and 5.8 m/s. Those from other sites may be suitable for small scale generation or as wind farms, with several small turbines connected together, to generate large enough wind power. The turbine matching results shows that turbines cut-in and rated wind speeds of between 2.0 and 3.0 m/s, and between 10 and 12.0 m/s respectively will be very suited to all the sites, particularly those in locations outside Lagos and Oyo States. The energy cost analysis shows that generation cost can be as low as 0.02 €/kWh and as high as 5.03/kWh, depending on the turbine model employed.

  13. Wind Loads on Structures

    DEFF Research Database (Denmark)

    Dyrbye, Claes; Hansen, Svend Ole

    Wind loads have to be taken into account when designing civil engineering structures. The wind load on structures can be systematised by means of the wind load chain: wind climate (global), terrain (wind at low height), aerodynamic response (wind load to pressure), mechanical response (wind...... pressure to structural response) and design criteria. Starting with an introduction of the wind load chain, the book moves on to meteorological considerations, atmospheric boundary layer, static wind load, dynamic wind load and scaling laws used in wind-tunnel tests. The dynamic wind load covers vibrations...... induced by wind turbulence, vortex shedding, flutter and galloping. The book gives a comprehensive treatment of wind effects on structures and it will be useful for consulting engineers designing wind-sensitive structures. It will also be valuable for students of civil engineering as textbook...

  14. A numerical study on the mechanism and optimization of wind-break structures for indirect air-cooling towers

    International Nuclear Information System (INIS)

    Gu, Hongfang; Wang, Haijun; Gu, Yuqian; Yao, Jianan

    2016-01-01

    Highlights: • Numerical study on the optimization of windbreak structure for IDAC was conducted. • Windbreak wall is the most effective structure but is affected by wind direction. • The louver is next best and it can be flexibly adjusted at the windy conditions. • An optimal louver opening was obtained for achieving a good cooling performance. - Abstract: The heat transfer performance of indirect air-cooling (IDAC) towers in large power stations is sensitive to the ambient wind velocity. To ensure the economic and reliable operation of units under windy conditions, it is important to conduct research on the optimization of different wind-break structures. This paper uses computational fluid dynamics method (CFD) to simulate the heat transfer performance of a 1000 MW IDAC tower power stations with four different wind-break structures namely, cross walls, wind-break walls, cross line-screen, and louvers. The research results show that the order of the effective heat transfer improvement of four wind-break structures is the wind-break, cross wall, line-screen and louvers. The wind-break wall is the most optimal structure, but its performance is strictly influenced by the direction and velocity of the wind, and the cross walls and cross line-screen structure have similar limitation in the practice operation. The louver is installed in each sector, and it is the next best option for increasing the heat transfer performance. It can be flexibly adjusted based on the wind direction and velocity. With the decrease in the louver opening, k, there is a decrease in the heat transfer rate of the windward sectors, and a significant increase in the heat transfer rate of the leeward sectors. Thus the total heat transfer rate of the IDAC tower can be improved tremendously. Based on the analysis of heat transfer and air flow mechanisms, there is an optimal opening, k, which achieves the largest heat transfer performance in an IDAC tower at each wind velocity. This study

  15. IEA Wind Task 26 - Multi-national Case Study of the Financial Cost of Wind Energy; Work Package 1 Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Schwabe, P.; Lensink, S.; Hand, M.

    2011-03-01

    The lifetime cost of wind energy is comprised of a number of components including the investment cost, operation and maintenance costs, financing costs, and annual energy production. Accurate representation of these cost streams is critical in estimating a wind plant's cost of energy. Some of these cost streams will vary over the life of a given project. From the outset of project development, investors in wind energy have relatively certain knowledge of the plant's lifetime cost of wind energy. This is because a wind energy project's installed costs and mean wind speed are known early on, and wind generation generally has low variable operation and maintenance costs, zero fuel cost, and no carbon emissions cost. Despite these inherent characteristics, there are wide variations in the cost of wind energy internationally, which is the focus of this report. Using a multinational case-study approach, this work seeks to understand the sources of wind energy cost differences among seven countries under International Energy Agency (IEA) Wind Task 26 - Cost of Wind Energy. The participating countries in this study include Denmark, Germany, the Netherlands, Spain, Sweden, Switzerland, and the United States. Due to data availability, onshore wind energy is the primary focus of this study, though a small sample of reported offshore cost data is also included.

  16. A comparative study between three sensorless control strategies for PMSG in wind energy conversion system

    Energy Technology Data Exchange (ETDEWEB)

    Brahmi, Jemaa; Krichen, Lotfi; Ouali, Abderrazak [Advanced Control and Energy Management Research Unit ENIS, Department of Electrical Engineering, University of Sfax, 3038 Sfax (Tunisia)

    2009-09-15

    This paper presents a comparative study of sliding mode, artificial neural network and model reference adaptive speed observers for a speed sensorless permanent magnet synchronous generator (PMSG) in wind energy conversion system (WECS). Wind velocity and position sensorless operating methods for wind generation system using observer are proposed only by measuring phase voltages and currents. Maximum wind energy extraction is achieved by running the wind turbine generator in variable-speed mode. In addition the three speed observers are compared to verify the robustness against parameter variations. (author)

  17. Simulation study for the Stratospheric Inferred Wind (SIW) sub-millimeter limb sounder

    Science.gov (United States)

    Baron, Philippe; Murtagh, Donal; Eriksson, Patrick; Ochiai, Satoshi

    2017-04-01

    The Stratospheric Inferred Wind is a micro satellite mission studied within the Swedish Innosat program. The objective of the Innosat program is to launch a scientific satellite every two years [1]. SIW has been selected together with two other missions as a candidate for the 2nd launch planned in 2020. If realized, SIW will be the first sub-millimetre (SMM) satellite mission designed for measuring horizontal wind between 30-80 km. It has been shown that such systems can provide relevant wind information in this altitude range where other satellite techniques lack sensitivity [2,3]. The other objective of the mission will be to continue the stratospheric monitoring at a time in which the current observing systems will probably be ended. SIW is equipped with a small payload (40x40x44 cm3, 17 kg and power of 47 W) consisting of a radiometer cooled to 70 K, an auto-correlator spectrometer (8 GHz bandwidth, 1 MHz resolution), and an antenna of 30 cm. The atmospheric limb will be scanned from 10 to 80 km at two perpendicular directions in order to reconstruct the horizontal wind vectors from the measured line-of-sight winds. Those are obtained from the small Doppler shift of molecular lines contained in two spectral bands simultaneously measured with the double-side band radiometer. One of the bands is centred at 655 GHz to measure a cluster of strong O3 lines. It is the best spectral band for wind measurements [4]. The second band is centred near 625 GHz, and together with the first band, it will allow us to measure a large number of molecules relevant for studying the stratospheric dynamics and chemistry (N2O, H2O, ClO, HCl, BrO, NO, HNO3,...). The 655 GHz O3 lines also provide temperature between 10-80 km with similar performances as those obtained if an oxygen line would have been used instead. In this presentation we will introduce SIW and discuss the measurement performances derived from simulations studies. [1] http://www.ohb.de/press-releases-details/ohb-sweden

  18. Modelling impacts of offshore wind farms on trophic web: the Courseulles-sur-Mer case study

    Science.gov (United States)

    Raoux, Aurore; Pezy, Jean-Philippe; Dauvin, Jean-Claude; Tecchio, samuele; Degraer, Steven; Wilhelmsson, Dan; Niquil, Nathalie

    2016-04-01

    The French government is planning the construction of three offshore wind farms in Normandy. These offshore wind farms will integrate into an ecosystem already subject to a growing number of anthropogenic disturbances such as transportation, fishing, sediment deposit, and sediment extraction. The possible effects of this cumulative stressors on ecosystem functioning are still unknown, but they could impact their resilience, making them susceptible to changes from one stable state to another. Understanding the behaviour of these marine coastal complex systems is essential in order to anticipate potential state changes, and to implement conservation actions in a sustainable manner. Currently, there are no global and integrated studies on the effects of construction and exploitation of offshore wind farms. Moreover, approaches are generally focused on the conservation of some species or groups of species. Here, we develop a holistic and integrated view of ecosystem impacts through the use of trophic webs modelling tools. Trophic models describe the interaction between biological compartments at different trophic levels and are based on the quantification of flow of energy and matter in ecosystems. They allow the application of numerical methods for the characterization of emergent properties of the ecosystem, also called Ecological Network Analysis (ENA). These indices have been proposed as ecosystem health indicators as they have been demonstrated to be sensitive to different impacts on marine ecosystems. We present here in detail the strategy for analysing the potential environmental impacts of the construction of the Courseulles-sur-Mer offshore wind farm (Bay of Seine) such as the reef effect through the use of the Ecopath with Ecosim software. Similar Ecopath simulations will be made in the future on the Le Tréport offshore wind farm site. Results will contribute to a better knowledge of the impacts of the offshore wind farms on ecosystems. They also allow to

  19. Western Wind and Solar Integration Study Phase 2 (Presentation)

    Energy Technology Data Exchange (ETDEWEB)

    Lew, D.; Brinkman, G.; Ibanez, E.; Kumar, N.; Lefton, S.; Jordan, G.; Venkataraman, S.; King, J.

    2013-06-01

    This presentation accompanies Phase 2 of the Western Wind and Solar Integration Study, a follow-on to Phase 1, which examined the operational impacts of high penetrations of variable renewable generation on the electric power system in the West and was one of the largest variable generation studies to date. High penetrations of variable generation can induce cycling of fossil-fueled generators. Cycling leads to wear-and-tear costs and changes in emissions. Phase 2 calculated these costs and emissions, and simulated grid operations for a year to investigate the detailed impact of variable generation on the fossil-fueled fleet. The presentation highlights the scope of the study and results.

  20. The Wind Forecast Improvement Project (WFIP). A Public/Private Partnership for Improving Short Term Wind Energy Forecasts and Quantifying the Benefits of Utility Operations -- the Northern Study Area

    Energy Technology Data Exchange (ETDEWEB)

    Finley, Cathy [WindLogics, St. Paul, MN (United States)

    2014-04-30

    individual wind plant and at the system-wide aggregate level over the one year study period showed that the research weather model-based power forecasts (all types) had lower overall error rates than the current operational weather model-based power forecasts, both at the individual wind plant level and at the system aggregate level. The bulk error statistics of the various model-based power forecasts were also calculated by season and model runtime/forecast hour as power system operations are more sensitive to wind energy forecast errors during certain times of year and certain times of day. The results showed that there were significant differences in seasonal forecast errors between the various model-based power forecasts. The results from the analysis of the various wind power forecast errors by model runtime and forecast hour showed that the forecast errors were largest during the times of day that have increased significance to power system operators (the overnight hours and the morning/evening boundary layer transition periods), but the research weather model-based power forecasts showed improvement over the operational weather model-based power forecasts at these times.

  1. Study of wind turbine foundations in cold climates

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2012-11-01

    This report provides an overview of the processes at work in soil in cold climates and their effect on wind turbine foundations. Havsnaes wind farm consists of 48 turbines located in Jaemtland county in central Sweden. Havsnaes has provided an appropriate research environment to investigate the engineering challenges related to the design and construction of wind turbine foundations in sub-arctic conditions and the experienced gained from this project informs this report.

  2. Prediction of tropical cyclone over North Indian Ocean using WRF model: sensitivity to scatterometer winds, ATOVS and ATMS radiances

    KAUST Repository

    Dodla, Venkata B.

    2016-05-03

    Tropical cyclone prediction, in terms of intensification and movement, is important for disaster management and mitigation. Hitherto, research studies were focused on this issue that lead to improvement in numerical models, initial data with data assimilation, physical parameterizations and application of ensemble prediction. Weather Research and Forecasting (WRF) model is the state-of-art model for cyclone prediction. In the present study, prediction of tropical cyclone (Phailin, 2013) that formed in the North Indian Ocean (NIO) with and without data assimilation using WRF model has been made to assess impacts of data assimilation. WRF model was designed to have nested two domains of 15 and 5 km resolutions. In the present study, numerical experiments are made without and with the assimilation of scatterometer winds, and radiances from ATOVS and ATMS. The model performance was assessed in respect to the movement and intensification of cyclone. ATOVS data assimilation experiment had produced the best prediction with least errors less than 100 km up to 60 hours and producing pre-deepening and deepening periods accurately. The Control and SCAT wind assimilation experiments have shown good track but the errors were 150-200 km and gradual deepening from the beginning itself instead of sudden deepening.

  3. PDF sensitivity studies from ATLAS measurements

    CERN Document Server

    Hanna, Remie; The ATLAS collaboration

    2015-01-01

    Several measurements performed by the ATLAS collaboration are either useful to constrain the proton structure or are affected by its associated uncertainties. The strange-quark density is rather poorly known at low x. Measurements of the W+c production and the inclusive W and Z differential cross sections are found to constrain the strange-quark density. Drell-Yan cross section measurements performed above and below the Z peak region have a different sensitivity to parton flavour, parton momentum fraction x and scale Q compared to measurements on the Z peak and can also be used to constrain the photon content of the proton. Measurements of the inclusive jet and photon cross sections are standard candles and can be useful to constrain the medium and high x gluon densities. Precision electroweak studies performed by ATLAS can be limited by the current knowledge on the proton structure. Among those are the measurement of the effective weak mixing angle and the mass of the W boson. Dedicated PDF studies were perf...

  4. Do Wind Turbines Affect Weather Conditions?: A Case Study in Indiana

    Directory of Open Access Journals (Sweden)

    Meghan F. Henschen

    2011-01-01

    Full Text Available Wind turbines are becoming increasingly widespread in the United States as the world looks for cleaner sources of energy. Scientists, policymakers, and citizens have strong opinions regarding the positive and negative effects of wind energy projects, and there is a great deal of misinformation about wind energy circulating on the Web and other media sources. The purpose of this study is to gain a better understanding of how the rotation of hundreds of turbines can influence local weather conditions within a wind farm and in the surrounding areas. This experiment measures temperature, atmospheric pressure, wind speed, wind direction, relative humidity, and evaporation with five weather instruments at Meadow Lake Wind Farm located in White, Jasper, and Benton Counties, Indiana, from November 4 through November 18, 2010. The data show that as wind passes throughout the wind farm, the air warms during the overnight and early morning hours and cools during daytime hours. Observed lower humidity rates and higher evaporation rates downwind also demonstrate that the air dries out as it travels through the wind farm. Further research over multiple seasons is necessary to examine the effects of warmer nighttime temperatures and drier conditions progressively downwind of the installation. Nevertheless, wind turbines did not negatively affect local weather patterns in our small-scale research and may actually prevent frost, which could have important positive implications for farmers by potentially prolonging the growing season.

  5. Experimental study of the impact of large-scale wind farms on land–atmosphere exchanges

    International Nuclear Information System (INIS)

    Zhang Wei; Markfort, Corey D; Porté-Agel, Fernando

    2013-01-01

    Large-scale wind farms, covering a significant portion of the land and ocean surface, may affect the transport of momentum, heat, mass and moisture between the atmosphere and the land locally and globally. To understand the wind-farm–atmosphere interaction, we conducted wind-tunnel experiments to study the surface scalar (heat) flux using model wind farms, consisting of more than ten rows of wind turbines—having typical streamwise and spanwise spacings of five and four rotor diameters—in a neutral boundary layer with a heated surface. The spatial distribution of the surface heat flux was mapped with an array of surface heat flux sensors within the quasi-developed regime of the wind-farm flow. Although the overall surface heat flux change produced by the wind farms was found to be small, with a net reduction of 4% for a staggered wind farm and nearly zero change for an aligned wind farm, the highly heterogeneous spatial distribution of the surface heat flux, dependent on the wind-farm layout, was significant. The difference between the minimum and maximum surface heat fluxes could be up to 12% and 7% in aligned and staggered wind farms, respectively. This finding is important for planning intensive agriculture practice and optimizing farm land use strategy regarding wind energy project development. The well-controlled wind-tunnel experiments presented in this study also provide a first comprehensive dataset on turbulent flow and scalar transport in wind farms, which can be further used to develop and validate new parameterizations of surface scalar fluxes in numerical models. (letter)

  6. Exploring Intercultural Sensitivity in Early Adolescence: A Mixed Methods Study

    Science.gov (United States)

    Mellizo, Jennifer M.

    2017-01-01

    The purpose of this mixed methods study was to explore levels of intercultural sensitivity in a sample of fourth to eighth grade students in the United States (n = 162). "Intercultural sensitivity" was conceptualised through Bennett's Developmental Model of Sensitivity, and assessed through the Adapted Intercultural Sensitivity Index.…

  7. Unique proteomic signature for radiation sensitive patients; a comparative study between normo-sensitive and radiation sensitive breast cancer patients

    Energy Technology Data Exchange (ETDEWEB)

    Skiöld, Sara [Center for Radiation Protection Research, Department of Molecular Biosciences, The Wernner-Gren Institute, Stockholm University, Stockholm (Sweden); Azimzadeh, Omid [Institute of Radiation Biology, German Research Center for Environmental Health, Helmholtz Zentrum München (Germany); Merl-Pham, Juliane [Research Unit Protein Science, German Research Center for Environmental Health, Helmholtz Zentrum München, Neuherberg (Germany); Naslund, Ingemar; Wersall, Peter; Lidbrink, Elisabet [Division of Radiotherapy, Radiumhemmet, Karolinska University Hospital, Stockholm (Sweden); Tapio, Soile [Institute of Radiation Biology, German Research Center for Environmental Health, Helmholtz Zentrum München (Germany); Harms-Ringdahl, Mats [Center for Radiation Protection Research, Department of Molecular Biosciences, The Wernner-Gren Institute, Stockholm University, Stockholm (Sweden); Haghdoost, Siamak, E-mail: Siamak.Haghdoost@su.se [Center for Radiation Protection Research, Department of Molecular Biosciences, The Wernner-Gren Institute, Stockholm University, Stockholm (Sweden)

    2015-06-15

    Highlights: • The unique protein expression profiles were found that separate radiosensitive from normal sensitive breast cancer patients. • The oxidative stress response, coagulation properties and acute phase response suggested to be the hallmarks of radiation sensitivity. - Abstract: Radiation therapy is a cornerstone of modern cancer treatment. Understanding the mechanisms behind normal tissue sensitivity is essential in order to minimize adverse side effects and yet to prevent local cancer reoccurrence. The aim of this study was to identify biomarkers of radiation sensitivity to enable personalized cancer treatment. To investigate the mechanisms behind radiation sensitivity a pilot study was made where eight radiation-sensitive and nine normo-sensitive patients were selected from a cohort of 2914 breast cancer patients, based on acute tissue reactions after radiation therapy. Whole blood was sampled and irradiated in vitro with 0, 1, or 150 mGy followed by 3 h incubation at 37 °C. The leukocytes of the two groups were isolated, pooled and protein expression profiles were investigated using isotope-coded protein labeling method (ICPL). First, leukocytes from the in vitro irradiated whole blood from normo-sensitive and extremely sensitive patients were compared to the non-irradiated controls. To validate this first study a second ICPL analysis comparing only the non-irradiated samples was conducted. Both approaches showed unique proteomic signatures separating the two groups at the basal level and after doses of 1 and 150 mGy. Pathway analyses of both proteomic approaches suggest that oxidative stress response, coagulation properties and acute phase response are hallmarks of radiation sensitivity supporting our previous study on oxidative stress response. This investigation provides unique characteristics of radiation sensitivity essential for individualized radiation therapy.

  8. Unique proteomic signature for radiation sensitive patients; a comparative study between normo-sensitive and radiation sensitive breast cancer patients

    International Nuclear Information System (INIS)

    Skiöld, Sara; Azimzadeh, Omid; Merl-Pham, Juliane; Naslund, Ingemar; Wersall, Peter; Lidbrink, Elisabet; Tapio, Soile; Harms-Ringdahl, Mats; Haghdoost, Siamak

    2015-01-01

    Highlights: • The unique protein expression profiles were found that separate radiosensitive from normal sensitive breast cancer patients. • The oxidative stress response, coagulation properties and acute phase response suggested to be the hallmarks of radiation sensitivity. - Abstract: Radiation therapy is a cornerstone of modern cancer treatment. Understanding the mechanisms behind normal tissue sensitivity is essential in order to minimize adverse side effects and yet to prevent local cancer reoccurrence. The aim of this study was to identify biomarkers of radiation sensitivity to enable personalized cancer treatment. To investigate the mechanisms behind radiation sensitivity a pilot study was made where eight radiation-sensitive and nine normo-sensitive patients were selected from a cohort of 2914 breast cancer patients, based on acute tissue reactions after radiation therapy. Whole blood was sampled and irradiated in vitro with 0, 1, or 150 mGy followed by 3 h incubation at 37 °C. The leukocytes of the two groups were isolated, pooled and protein expression profiles were investigated using isotope-coded protein labeling method (ICPL). First, leukocytes from the in vitro irradiated whole blood from normo-sensitive and extremely sensitive patients were compared to the non-irradiated controls. To validate this first study a second ICPL analysis comparing only the non-irradiated samples was conducted. Both approaches showed unique proteomic signatures separating the two groups at the basal level and after doses of 1 and 150 mGy. Pathway analyses of both proteomic approaches suggest that oxidative stress response, coagulation properties and acute phase response are hallmarks of radiation sensitivity supporting our previous study on oxidative stress response. This investigation provides unique characteristics of radiation sensitivity essential for individualized radiation therapy

  9. Wind driven mobile charging of automobile battery- A case study ...

    African Journals Online (AJOL)

    This paper deals with implementation of mobile wind driven generator technology to produce electricity in charging of two wheeler (12V) automobile battery. The use of PWM methodology with pulse charging method at a constant rate has been adopted for this purpose. The low speed PMSG driven by wind at speed of ...

  10. Virginia Offshore Wind Cost Reduction Through Innovation Study (VOWCRIS) (Poster)

    Energy Technology Data Exchange (ETDEWEB)

    Maples, B.; Campbell, J.; Arora, D.

    2014-10-01

    The VOWCRIS project is an integrated systems approach to the feasibility-level design, performance, and cost-of-energy estimate for a notional 600-megawatt offshore wind project using site characteristics that apply to the Wind Energy Areas of Virginia, Maryland and North Carolina.

  11. Preliminary modelling study of ice accretion on wind turbines

    DEFF Research Database (Denmark)

    Pedersen, Marie Cecilie; Yin, Chungen

    2014-01-01

    One of the main challenges associated with cold-climate wind energy is icing on wind turbines and a series of icing-induced problems such as production loss, blade fatigue and safety issues. Because of the difficulties with on-site measurements, simulations are often used to understand and predic...

  12. Control strategies for wind farm power optimization: LES study

    Science.gov (United States)

    Ciri, Umberto; Rotea, Mario; Leonardi, Stefano

    2017-11-01

    Turbines in wind farms operate in off-design conditions as wake interactions occur for particular wind directions. Advanced wind farm control strategies aim at coordinating and adjusting turbine operations to mitigate power losses in such conditions. Coordination is achieved by controlling on upstream turbines either the wake intensity, through the blade pitch angle or the generator torque, or the wake direction, through yaw misalignment. Downstream turbines can be adapted to work in waked conditions and limit power losses, using the blade pitch angle or the generator torque. As wind conditions in wind farm operations may change significantly, it is difficult to determine and parameterize the variations of the coordinated optimal settings. An alternative is model-free control and optimization of wind farms, which does not require any parameterization and can track the optimal settings as conditions vary. In this work, we employ a model-free optimization algorithm, extremum-seeking control, to find the optimal set-points of generator torque, blade pitch and yaw angle for a three-turbine configuration. Large-Eddy Simulations are used to provide a virtual environment to evaluate the performance of the control strategies under realistic, unsteady incoming wind. This work was supported by the National Science Foundation, Grants No. 1243482 (the WINDINSPIRE project) and IIP 1362033 (I/UCRC WindSTAR). TACC is acknowledged for providing computational time.

  13. Final Project Report, Bristol Bay Native Corporation Wind and Hydroelectric Feasibility Study

    Energy Technology Data Exchange (ETDEWEB)

    Vaught, Douglas J.

    2007-03-31

    The Bristol Bay Native Corporation (BBNC) grant project focused on conducting nine wind resource studies in eight communities in the Bristol Bay region of southwest Alaska and was administered as a collaborative effort between BBNC, the Alaska Energy Authority, Alaska Village Electric Cooperative, Nushagak Electric Cooperative (NEC), Naknek Electric Association (NEA), and several individual village utilities in the region. BBNC’s technical contact and the project manager for this study was Douglas Vaught, P.E., of V3 Energy, LLC, in Eagle River, Alaska. The Bristol Bay region of Alaska is comprised of 29 communities ranging in size from the hub community of Dillingham with a population of approximately 3,000 people, to a few Native Alaska villages that have a few tens of residents. Communities chosen for inclusion in this project were Dillingham, Naknek, Togiak, New Stuyahok, Kokhanok, Perryville, Clark’s Point, and Koliganek. Selection criteria for conduction of wind resource assessments in these communities included population and commercial activity, utility interest, predicted Class 3 or better wind resource, absence of other sources of renewable energy, and geographical coverage of the region. Beginning with the first meteorological tower installation in October 2003, wind resource studies were completed at all sites with at least one year, and as much as two and a half years, of data. In general, the study results are very promising for wind power development in the region with Class 6 winds measured in Kokhanok; Class 4 winds in New Stuyahok, Clark’s Point, and Koliganek; Class 3 winds in Dillingham, Naknek, and Togiak; and Class 2 winds in Perryville. Measured annual average wind speeds and wind power densities at the 30 meter level varied from a high of 7.87 meters per second and 702 watts per square meter in Kokhanok (Class 6 winds), to a low of 4.60 meters per second and 185 watts per square meter in Perryville (Class 2 winds).

  14. Microplastics in a wind farm area: A case study at the Rudong Offshore Wind Farm, Yellow Sea, China.

    Science.gov (United States)

    Wang, Teng; Zou, Xinqing; Li, Baojie; Yao, Yulong; Li, Jiasheng; Hui, Hejiu; Yu, Wenwen; Wang, Chenglong

    2018-03-01

    Despite the rapid construction of offshore wind farms, the available information regarding the risks of this type of development in terms of emerging pollutants, particularly microplastics, is scarce. In this study, we quantified the level of microplastic pollution at an offshore wind farm in the Yellow Sea, China, in 2016. The abundance of microplastics was 0.330 ± 0.278 items/m 3 in the surface water and 2.58 ± 1.14 items/g (dry) in the sediment. To the best of our knowledge, the level of microplastic pollution in our study area was slightly higher than that in coastal areas around the world. The microplastics detected in the surface waters and sediments were mainly fibrous (75.3% and 68.7%, respectively) and consisted of some granules and films. The microplastics in the samples might originate from garments or ropes via wastewater discharge. The abundance of plastic in the water and sediment samples collected from the wind farm area was lower than that in the samples collected from outside the wind farm area. The anthropogenic hydrodynamic effect was the main factor affecting the local distribution of microplastics. The presence of a wind farm could increase the bed shear stress during ebb tide, disturbing the bed sediment, facilitating its initiation and transport, and ultimately increasing the ease of washing away the microplastics adhered to the sediment. This study will serve as a reference for further studies of the distribution and migration of microplastics in coastal zones subjected to similar marine utilization. Copyright © 2018 Elsevier Ltd. All rights reserved.

  15. The necessary distance between large wind farms offshore - study

    Energy Technology Data Exchange (ETDEWEB)

    Frandsen, S.; Barthelmie, R.; Pryor, S.; Rathmann, O.; Larsen, S.; Hoejstrup, J.; Nielsen, P.; Lybech Thoegersen, M.

    2004-08-01

    A review of state of the art wake and boundary layer wind farms was conducted. The predictions made for wind recovery distances (that might be used to estimate optimal placing of neighbouring wind farms) range between 2 and 14 km. In order to model the link between wakes and the boundary layer the new Storpark Analytical Model has been developed and evaluated. As it is often the need for offshore wind farms, the model handles a regular array-geometry with straight rows of wind turbines and equidistant spacing between units in each row and equidistant spacing between rows. Firstly, the case with the flow direction being parallel to rows in a rectangular geometry is considered by defining three flow regimes. Secondly, when the flow is not in line with the main rows, solutions are found for the patterns of wind turbine units emerging corresponding to each wind direction. The model complex will be adjusted and calibrated with measurements in the near future. (au)

  16. Modelling wind speed parameters for computer generation of wind speed in Flanders. A case study using small wind turbines in an urban environment

    Energy Technology Data Exchange (ETDEWEB)

    Gay, Michael; Dessel, Michel van [Lessius Mechelen, Campus De Nayer (Belgium). Dept. of Applied Engineering; Driesen, Johan [Leuven Univ. (Belgium). Dept. of Electrical Engineering / ESAT

    2012-07-01

    The calculation of wind energy parameters is made for small wind turbines on moderate height in a suburban environment. After using the measured data, the same parameters were calculated using first order Markov chain computer generated data. Some characteristics of the wind and the wind power were preserved using Markov, other were not. (orig.)

  17. Large-scale wind power in New Brunswick : a regional scenario study towards 2025

    International Nuclear Information System (INIS)

    2008-08-01

    This paper discussed the large-scale development of wind power in New Brunswick and evaluated Danish experiences with wind development as a template for developing wind resources in the Maritimes region. The study showed that New Brunswick and the Maritimes region have good wind resources, and that the province will gain significant economic benefits from deploying between 5500 and 7500 MW of wind power capacity by 2025. Wind power development will contribute to the security of supply in the region and reduce air pollution. Carbon regulation and renewable portfolio standards will improve the competitiveness of wind power. Electricity generated by wind power plants in the Maritimes can be sold to other provinces in Canada, as well as to the heavily populated New England region of the United States. A high level of cooperation between markets in the Maritimes area and neighbouring New England and Quebec systems will be required in addition to load flow analyses of electricity systems. Denmark's experiences with developing wind power indicate that existing market designs must be restructured to allow for higher levels of competition. A strong system operator is required to integrate wind power into the system. It was concluded that strong political leadership is required to ensure the sustainable development of the region. 5 refs., 4 tabs., 9 figs

  18. Effect of turbulence intensity on PM emission of heavy duty diesel trucks - Wind tunnel studies

    Science.gov (United States)

    Littera, D.; Cozzolini, A.; Besch, M.; Carder, D.; Gautam, M.

    2017-08-01

    Stringent emission regulations have forced drastic technological improvements in diesel aftertreatment systems, particularly in reducing Particulate Matter (PM) emissions. The formation and evolution of PM from modern engines are more sensitive to overall changes in the dilution process, such as rapidity of mixing, background PM present in the air. These technological advancements were made in controlled laboratory environments compliant with measurement standards (i.e. Code of Federal Regulation CFR in the USA) and are not fully representative of real-world emissions from these engines or vehicles. In light of this, a specifically designed and built wind tunnel by West Virginia University (WVU) is used for the study of the exhaust plume of a heavy-duty diesel vehicle, providing a better insight in the dilution process and the representative nanoparticles emissions in a real-world scenario. The subsonic environmental wind tunnel is capable of accommodating a full-sized heavy-duty truck and generating wind speeds in excess of 50mph. A three-dimensional gantry system allows spanning the test section and sample regions in the plume with accuracy of less than 5 mm. The gantry system is equipped with engine exhaust gas analyzers and PM sizing instruments. The investigation involves three different heavy-duty Class-8 diesel vehicles representative of three emission regulation standards, namely a US-EPA 2007 compliant, a US-EPA 2010 compliant, and a baseline vehicle without any aftertreatment technologies as a pre US-EPA 2007, respectively. The testing procedure includes three different vehicle speeds: idling, 20mph, and 35mph. The vehicles were tested on WVU's medium-duty chassis dynamometer, with the load applied to the truck reflecting the road load equation at the corresponding vehicle test speeds. Wind tunnel wind speed and vehicle speed were maintained in close proximity to one another during the entire test. Results show that the cross-sectional plume area

  19. Vandenberg Air Force Base Pressure Gradient Wind Study

    Science.gov (United States)

    Shafer, Jaclyn A.

    2013-01-01

    Warning category winds can adversely impact day-to-day space lift operations at Vandenberg Air Force Base (VAFB) in California. NASA's Launch Services Program and other programs at VAFB use wind forecasts issued by the 30 Operational Support Squadron Weather Flight (30 OSSWF) to determine if they need to limit activities or protect property such as a launch vehicle. The 30 OSSWF tasked the AMU to develop an automated Excel graphical user interface that includes pressure gradient thresholds between specific observing stations under different synoptic regimes to aid forecasters when issuing wind warnings. This required the AMU to determine if relationships between the variables existed.

  20. Alliance created to study wind-generated power potential

    International Nuclear Information System (INIS)

    Anon.

    1991-01-01

    Wind-generated power may get a boost from a new consortium of companies that have joined together to expand the potential across the country for this cheap, renewable energy source. Niagara Mohawk Power Corporation has announced that it will join with the Pacific Gas and Electric Company (PG ampersand E), the Electric Power Research Institute (EPRI) and US Windpower, Inc., in developing an advanced, 33-meter, variable-speed wind turbine that reduced the cost and improves the power quality of wind energy. The majority of the estimated $20 million cost will be provided by US Windpower

  1. Evaluation of the Trajectory Sensitivity Analysis of the DFIG Control Parameters in Response to Changes in Wind Speed and the Line Impedance Connection to the Grid DFIG

    Directory of Open Access Journals (Sweden)

    Mehdi Fooladgar

    2015-01-01

    Full Text Available Economic and environmental conditions often make large stations and transmission lines, restrictions are placed. Small and medium-sized production units connected to existing systems as a strategy is in progress. These units are usually near the center of the load placed and distributed generators (DG famous are the DG are allowed types vary, such as induction generators rack squirrel-connected wind turbines, generators fed induction double mounted wind turbines, fuel cells connected to the system by power electronic converters or synchronous generator connected to the turbine combustion [10]. This way sensitivity analysis in systems of distributed generation (DG is assessed. It is shown that the method can detect the effect of control parameters listed wind turbine connected to a double-fed induction generator (DFIG Badoou the impedance of the changing the speed of on the stability of the transmission line useful system invested. The control parameters of the importance of influencing the behavior of DFIG are divided.

  2. Ornithological studies of the Cold Northcott Wind Farm in the spring/summer 1994

    International Nuclear Information System (INIS)

    1996-01-01

    Results of ornithological studies carried out at Cold Northcott Wind Farm in North Cornwall during 1994 are presented. Flight patterns of species using the area were studied as were breeding patterns and bird mortality due to collisions with wind turbines. No significant effect on the spring and summer bird communities was observed. Long-term influences on the birds seem, rather, to stem from large scale population changes and local agricultural practice. Wind strength was shown to affect flight patterns in some species, but turbine operation seems unrelated. Death by collision with wind turbines is shown to be very rare. (UK)

  3. Study on Determination Method of Fatigue Testing Load for Wind Turbine Blade

    Science.gov (United States)

    Liao, Gaohua; Wu, Jianzhong

    2017-07-01

    In this paper, the load calculation method of the fatigue test was studied for the wind turbine blade under uniaxial loading. The characteristics of wind load and blade equivalent load were analyzed. The fatigue property and damage theory of blade material were studied. The fatigue load for 2MW blade was calculated by Bladed, and the stress calculated by ANSYS. Goodman modified exponential function S-N curve and linear cumulative damage rule were used to calculate the fatigue load of wind turbine blades. It lays the foundation for the design and experiment of wind turbine blade fatigue loading system.

  4. Should we build wind farms close to load or invest in transmission to access better wind resources in remote areas? A case study in the MISO region

    International Nuclear Information System (INIS)

    Lamy, Julian V.; Jaramillo, Paulina; Azevedo, Inês L.; Wiser, Ryan

    2016-01-01

    Wind speeds in remote areas are sometimes very high, but transmission costs to access these locations can be prohibitive. We present a conceptual model to estimate the economics of accessing high quality wind resources in remote areas to comply with renewable energy policy targets, and apply the model to the Midwestern grid (MISO) as a case study. We assess the goal of providing 40 TWh of new wind generation while minimizing costs, and include temporal aspects of wind power (variability costs and correlation to market prices) as well as total wind power produced from different farms. We find that building wind farms in North/South Dakota (windiest states) compared to Illinois (less windy, but close to load) would only be economical if the incremental transmission costs to access them were below $360/kW of wind capacity (break-even value). Historically, the incremental transmission costs for wind development in North/South Dakota compared to in Illinois are about twice this value. However, the break-even incremental transmission cost for wind farms in Minnesota/Iowa (also windy states) is $250/kW, which is consistent with historical costs. We conclude that wind development in Minnesota/Iowa is likely more economical to meet MISO renewable targets compared to North/South Dakota or Illinois. - Highlights: •We evaluate the economics of building wind farms in remote areas in MISO. •We present a conceptual wind site selection model to meet 40 TWh of new wind. •We use the model to compare remote windy sites to less windy ones closer to load. •We show break-even transmission costs that would justify remote wind development. •Comparing break-even values to historical costs, MN/IA sites are most economical.

  5. Noise from wind power plants. A study in anticipation of the recommendation from the Swedish Environmental Protection Agency

    International Nuclear Information System (INIS)

    Almgren, Martin

    2006-03-01

    Noise from wind turbines are today treated as industrial noise sources according to the guidelines for external industry noise set by Naturvaardsverket (the Swedish Environmental Protection Agency) in RR 1978:5. A praxis has been established with recommended limit 40 dBA equivalent continuous sound pressure level outside dwellings day, evening and night. Naturvaardsverket is planning new guidelines specific for wind turbine noise. A draft was presented at an information meeting 13th May 2005. Special requirements, which in some cases may be far-reaching, are planned for wind turbines. The purpose of this investigation is to illustrate the fairness of the planned requirements. Application of the recommended prediction model for sound propagation above a sea surface in the draft of Naturvaardsverket may lead to serious consequences for the planning of wind power plants near the coast. Research with measurements on sound propagation above water is at present made by the Royal Institute of Technology in Kalmarsund in Sweden. The results of these measurements, which probably will be completed during the spring 2006, should be waited for before a prediction model is recommended. If the model would be valid for sound propagation from wind turbines at sea, there should be some reports on complaint on noise from offshore based wind power plants. We have not been able to locate such complaints in Sweden (Bockstigen), in Denmark (Middelgrunden, Nystedts havmoellepark and Horns rev) or in the Netherlands. For Middelgrund and Nysted, the sound level calculated with Naturvaardsverkets model at 4,5 km and 7 km respectively is around 48 dBA. According to Swedish studies, such a level is annoying to many people. Two methods to set out limits for wind turbine noise are used internationally. In the first an absolute limit for the equivalent continuous sound pressure level is set. In the other, the sound pressure level is related to the background noise level. Naturvaardsverket is

  6. Interacting Winds in Eclipsing Symbiotic Systems – The Case Study ...

    Indian Academy of Sciences (India)

    produced by the collision of two stellar winds (Vogel 1991, 1993; Girard & Willson ... Therefore, in the nebular environment an energetic zone .... 1b and 1d). .... By applying Kepler's second law, we obtain the time required to cover the corre-.

  7. Saturn radio emission and the solar wind - Voyager-2 studies

    International Nuclear Information System (INIS)

    Desch, M.D.; Rucker, H.O.; Observatorium Lustbuhel, Graz, Austria)

    1985-01-01

    Voyager 2 data from the Plasma Science experiment, the Magnetometer experiment and the Planetary Radio Astronomy experiment were used to analyze the relationship between parameters of the solar wind/interplanetary medium and the nonthermal Saturn radiation. Solar wind and interplanetary magnetic field properties were combined to form quantities known to be important in controlling terrestrial magnetospheric processes. The Voyager 2 data set used in this investigation consists of 237 days of Saturn preencounter measurements. However, due to the immersion of Saturn and the Voyager 2 spacecraft into the extended Jupiter magnetic tail, substantial periods of the time series were lacking solar wind data. To cope with this problem a superposed epoch method (CHREE analysis) was used. The results indicate the superiority of the quantities containing the solar wind density in stimulating the radio emission of Saturn - a result found earlier using Voyager 1 data - and the minor importance of quantities incorporating the interplanetary magnetic field. 10 references

  8. Study of the AC machines winding having fractional q

    Science.gov (United States)

    Bespalov, V. Y.; Sidorov, A. O.

    2018-02-01

    The winding schemes with a fractional numbers of slots per pole and phase q have been known and used for a long time. However, in the literature on the low-noise machines design there are not recommended to use. Nevertheless, fractional q windings have been realized in many applications of special AC electrical machines, allowing to improve their performance, including vibroacoustic one. This paper deals with harmonic analysis of windings having integer and fractional q in permanent magnet synchronous motors, a comparison of their characteristics is performed, frequencies of subharmonics are revealed. Optimal winding pitch design is found giving reduce the amplitudes of subharmonics. Distribution factors for subharmonics, fractional and high-order harmonics are calculated, results analysis is represented, allowing for giving recommendations how to calculate distribution factors for different harmonics when q is fractional.

  9. Wind profile radar for study of Antarctic air circulation

    International Nuclear Information System (INIS)

    Ragaini, E.; Sarango, M.F.; Vasquez, E.H.

    1992-01-01

    After a brief discussion of meteorological methods used in the Antarctic, the paper gives an outline of a coordinated international research project whose objective is to set up a wind profiler radar station that would give meteorologists information regarding Antarctic atmospheric dynamics useful in their investigation of the causes and effects of the hole in the ozone layer. The radar instrumentation is to provide continuous readings of wind velocity at varying altitudes above the polar continent

  10. Wind Tunnel Experiments to Study Chaparral Crown Fires.

    Science.gov (United States)

    Cobian-Iñiguez, Jeanette; Aminfar, AmirHessam; Chong, Joey; Burke, Gloria; Zuniga, Albertina; Weise, David R; Princevac, Marko

    2017-11-14

    The present protocol presents a laboratory technique designed to study chaparral crown fire ignition and spread. Experiments were conducted in a low velocity fire wind tunnel where two distinct layers of fuel were constructed to represent surface and crown fuels in chaparral. Chamise, a common chaparral shrub, comprised the live crown layer. The dead fuel surface layer was constructed with excelsior (shredded wood). We developed a methodology to measure mass loss, temperature, and flame height for both fuel layers. Thermocouples placed in each layer estimated temperature. A video camera captured the visible flame. Post-processing of digital imagery yielded flame characteristics including height and flame tilt. A custom crown mass loss instrument developed in-house measured the evolution of the mass of the crown layer during the burn. Mass loss and temperature trends obtained using the technique matched theory and other empirical studies. In this study, we present detailed experimental procedures and information about the instrumentation used. The representative results for the fuel mass loss rate and temperature filed within the fuel bed are also included and discussed.

  11. Different Models for Forecasting Wind Power Generation: Case Study

    Directory of Open Access Journals (Sweden)

    David Barbosa de Alencar

    2017-11-01

    Full Text Available Generation of electric energy through wind turbines is one of the practically inexhaustible alternatives of generation. It is considered a source of clean energy, but still needs a lot of research for the development of science and technologies that ensures uniformity in generation, providing a greater participation of this source in the energy matrix, since the wind presents abrupt variations in speed, density and other important variables. In wind-based electrical systems, it is essential to predict at least one day in advance the future values of wind behavior, in order to evaluate the availability of energy for the next period, which is relevant information in the dispatch of the generating units and in the control of the electrical system. This paper develops ultra-short, short, medium and long-term prediction models of wind speed, based on computational intelligence techniques, using artificial neural network models, Autoregressive Integrated Moving Average (ARIMA and hybrid models including forecasting using wavelets. For the application of the methodology, the meteorological variables of the database of the national organization system of environmental data (SONDA, Petrolina station, from 1 January 2004 to 31 March 2017, were used. A comparison among results by different used approaches is also done and it is also predicted the possibility of power and energy generation using a certain kind of wind generator.

  12. Aerodynamic study of a small horizontal-axis wind turbine

    Directory of Open Access Journals (Sweden)

    Cornelia NITA

    2012-06-01

    Full Text Available The wind energy is deemed as one of the most durable energetic variants of the future because the wind resources are immense. Furthermore, one predicts that the small wind turbine will play a vital role in the urban environment. Unfortunately, nowadays, the noise emissions from wind turbines represent one of the main obstacles to widespread the use in populated zones. Moreover, the energetic efficiency of these wind turbines has to be high even at low and medium wind velocities because, usually the cities are not windy places. The numerical results clearly show that the wakes after the trailing edge are the main noise sources. In order to decrease the power of these noise sources, we should try to decrease the intensity of wakes after the trailing edge, i.e. the aerodynamic fields from pressure and suction sides would have to be almost the same near trailing edge. Furthermore, one observes a strong link between transport (circumferential velocity and acoustic power level, i.e. if the transport velocity increases, the acoustic power level also augments.

  13. A Study of Wind Farm Stabilization Using DFIG or STATCOM Considering Grid Requirements

    Directory of Open Access Journals (Sweden)

    K. E Okedu

    2010-01-01

    Full Text Available Recently, the grid codes require taking into account the reactive power of the wind farm in order to contribute to the networkstability, thus operating the wind farm as active compensator devices. This paper presents a comparative study of stabilizinga wind farm using (Doubly Fed Induction Generators DFIGs or using a (Static Synchronous Compensator STATCOM duringwind speed change and grid fault. Simulation results show that the wind farm could be effectively stabilized with bothsystems, but at a reduced cost with the DFIGs system because it can provide reactive power through its frequency converterswithout an external reactive power compensation unit like the STATCOM system significant.

  14. Critical evaluation of financial supporting schemes for wind-based projects: Case study Greece

    International Nuclear Information System (INIS)

    Kaldellis, J.K.

    2011-01-01

    After a long stagnating period during the second half of the 1990s, the market of wind energy in Greece was described by remarkable but unstable growth rates that resulted in the operation of 1 GW of wind power by the end of 2009. Still though, penetration of wind energy is not the one anticipated. On the other hand, national targets regarding the Renewable Energy Sources' (RES) contribution and existence of excellent wind potential areas across Greece challenge new wind energy investments. Acknowledging the unsteady development rates of wind power in Greece, efficiency of the State support mechanisms is currently investigated. Based on an analytical evaluation model, the investigation undertaken is extended to provide a detailed cost-benefit analysis of several wind energy case studies, including mainland and island applications as well as comparison with both conventional power stations and photovoltaic plants. For this purpose, the financial support provided by the State is directly compared with benefits accruing from the operation of wind parks, considering also the avoidance of social costs deriving from thermal power stations. Based on the results obtained, the beneficial characteristics of wind energy applications for the Greek society are clearly demonstrated, especially in the case of non-interconnected island grids. - Research highlights: → Since the mid-1990s, growth of wind power capacity in Greece has been unstable. → As a result, integration of wind energy is not the one anticipated. → Considering the situation, efficiency of State support mechanisms is evaluated. → An analytical cost-benefit model is developed and applied to various case studies. → Benefits from wind energy, especially in island regions, are designated.

  15. Wind Power Forecasting Error Frequency Analyses for Operational Power System Studies: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Florita, A.; Hodge, B. M.; Milligan, M.

    2012-08-01

    The examination of wind power forecasting errors is crucial for optimal unit commitment and economic dispatch of power systems with significant wind power penetrations. This scheduling process includes both renewable and nonrenewable generators, and the incorporation of wind power forecasts will become increasingly important as wind fleets constitute a larger portion of generation portfolios. This research considers the Western Wind and Solar Integration Study database of wind power forecasts and numerical actualizations. This database comprises more than 30,000 locations spread over the western United States, with a total wind power capacity of 960 GW. Error analyses for individual sites and for specific balancing areas are performed using the database, quantifying the fit to theoretical distributions through goodness-of-fit metrics. Insights into wind-power forecasting error distributions are established for various levels of temporal and spatial resolution, contrasts made among the frequency distribution alternatives, and recommendations put forth for harnessing the results. Empirical data are used to produce more realistic site-level forecasts than previously employed, such that higher resolution operational studies are possible. This research feeds into a larger work of renewable integration through the links wind power forecasting has with various operational issues, such as stochastic unit commitment and flexible reserve level determination.

  16. Experimental study of improved HAWT performance in simulated natural wind by an active controlled multi-fan wind tunnel

    Science.gov (United States)

    Toshimitsu, Kazuhiko; Narihara, Takahiko; Kikugawa, Hironori; Akiyoshi, Arata; Kawazu, Yuuya

    2017-04-01

    The effects of turbulent intensity and vortex scale of simulated natural wind on performance of a horizontal axis wind turbine (HAWT) are mainly investigated in this paper. In particular, the unsteadiness and turbulence of wind in Japan are stronger than ones in Europe and North America in general. Hence, Japanese engineers should take account of the velocity unsteadiness of natural wind at installed open-air location to design a higher performance wind turbine. Using the originally designed five wind turbines on the basis of NACA and MEL blades, the dependencies of the wind frequency and vortex scale of the simulated natural wind are presented. As the results, the power coefficient of the newly designed MEL3-type rotor in the simulated natural wind is 130% larger than one in steady wind.

  17. A study of single multiplicative neuron model with nonlinear filters for hourly wind speed prediction

    International Nuclear Information System (INIS)

    Wu, Xuedong; Zhu, Zhiyu; Su, Xunliang; Fan, Shaosheng; Du, Zhaoping; Chang, Yanchao; Zeng, Qingjun

    2015-01-01

    Wind speed prediction is one important methods to guarantee the wind energy integrated into the whole power system smoothly. However, wind power has a non–schedulable nature due to the strong stochastic nature and dynamic uncertainty nature of wind speed. Therefore, wind speed prediction is an indispensable requirement for power system operators. Two new approaches for hourly wind speed prediction are developed in this study by integrating the single multiplicative neuron model and the iterated nonlinear filters for updating the wind speed sequence accurately. In the presented methods, a nonlinear state–space model is first formed based on the single multiplicative neuron model and then the iterated nonlinear filters are employed to perform dynamic state estimation on wind speed sequence with stochastic uncertainty. The suggested approaches are demonstrated using three cases wind speed data and are compared with autoregressive moving average, artificial neural network, kernel ridge regression based residual active learning and single multiplicative neuron model methods. Three types of prediction errors, mean absolute error improvement ratio and running time are employed for different models’ performance comparison. Comparison results from Tables 1–3 indicate that the presented strategies have much better performance for hourly wind speed prediction than other technologies. - Highlights: • Developed two novel hybrid modeling methods for hourly wind speed prediction. • Uncertainty and fluctuations of wind speed can be better explained by novel methods. • Proposed strategies have online adaptive learning ability. • Proposed approaches have shown better performance compared with existed approaches. • Comparison and analysis of two proposed novel models for three cases are provided

  18. Studying wind energy/bird interactions: a guidance document. Metrics and methods for determining or monitoring potential impacts on birds at existing and proposed wind energy sites

    Science.gov (United States)

    Anderson, R.; Morrison, M.; Sinclair, K.; Strickland, D.; Davis, H.; Kendall, W.

    1999-01-01

    In the 1980s little was known about the potential environmental effects associated with large scale wind energy development. Although wind turbines have been used in farming and remote location applications throughout this country for centuries, impacts on birds resulting from these dispersed turbines had not been reported. Thus early wind energy developments were planned, permitted, constructed, and operated with little consideration for the potential effects on birds. In the ensuing years wind plant impacts on birds became a source of concern among a number of stakeholder groups. Based on the studies that have been done to date, significant levels of bird fatalities have been identified at only one major commercial wind energy development in the United States. Research on wind energy/bird interactions has spanned such a wide variety of protocols and vastly different levels of study effort that it is difficult to make comparisons among study findings. As a result there continues to be interest, confusion, and concern over wind energy development's potential impacts on birds. Some hypothesize that technology changes, such as less dense wind farms with larger, slower-moving turbines, will decrease the number of bird fatalities from wind turbines. Others hypothesize that, because the tip speed may be the same or faster, new turbines will not result in decreased bird fatalities but may actually increase bird impacts. Statistically significant data sets from scientifically rigorous studies will be required before either hypothesis can be tested.

  19. Study on the snow drifting modelling criteria in boundary layer wind tunnels

    Directory of Open Access Journals (Sweden)

    Georgeta BĂETU

    2014-07-01

    Full Text Available The paper presents a study on modelling the wind drifting of the snow deposited on the flat roofs of buildings in wind tunnel. The physical model of snow drifting in wind tunnel simulating the urban exposure to wind action is not frequently reported in literature, but is justified by the serious damages under accidental important snow falls combined with strong wind actions on the roofs of various buildings. A uniform layer of snow deposited on the flat roof was exposed to wind action in order to obtain the drifting. The parameters involved in the modelling at reduced scale, with particles of glass beads, of the phenomenon of transportation of the snow from the roof were analysed, particularly the roughness length and the friction wind speed. A numerical simulation in ANSYS CFX program was developed in parallel, by which a more accurate visualization of the particularities of the wind flow over the roof was possible, in the specific areas where the phenomenon of snow transportation was more susceptible to occur. Modified roughness length and friction wind speed were determined through methods used in the literature, an attempt being made in this work to analyse the factors that influence their values.

  20. Review of high-sensitivity Radon studies

    Science.gov (United States)

    Wojcik, M.; Zuzel, G.; Simgen, H.

    2017-10-01

    A challenge in many present cutting-edge particle physics experiments is the stringent requirements in terms of radioactive background. In peculiar, the prevention of Radon, a radioactive noble gas, which occurs from ambient air and it is also released by emanation from the omnipresent progenitor Radium. In this paper we review various high-sensitivity Radon detection techniques and approaches, applied in the experiments looking for rare nuclear processes happening at low energies. They allow to identify, quantitatively measure and finally suppress the numerous sources of Radon in the detectors’ components and plants.

  1. Bats and offshore wind turbines studied in southern Scandinavia

    Energy Technology Data Exchange (ETDEWEB)

    Ahlen, Ingemar; Bach, Lothar; Baagoee, Hans J.; Pettersson, Jan

    2007-07-15

    A pilot study 2002-2003 at turbines on land showed that certain locations in the landscape could explain some of the casualty risks and the main reasons for collisions were found. During the 2005 introductory studies and in the project 2006 on bats in offshore areas in Kalmarsund we could confirm earlier known flyways from coastal points and found an extensive activity of passing migrants but also of resident species coming from various directions to areas with an abundance of insects. Observations were made at Utgrunden and Yttre Stengrund in Kalmarsund in the Baltic Sea and in Oeresund between Sweden and Denmark. The observers onboard the boats and at the coastal points where bats take off used ultrasound detectors, strong portable spotlights and at special times also thermal camera. Boxes for automatic recording of bats were used on land, were placed on the turbines, and on the boat's cap. These methods resulted in a total of 12,354 observations of bats, 3,830 over the sea and 8,524 on land. Bats fly over the sea in winds up to about 10 m/s, a major part of the activity took place at wind speeds less than 5 m/s. Bats of 10 species were observed on the open sea and all of them were foraging at suitable weather conditions, which means calm weather or light breeze. The bats did not avoid the turbines. On the contrary they stayed for shorter or longer periods hunting close to the windmills because of the accumulation of flying insects. Hunting close to the blades was observed, why the risk of colliding might be comparable to land-based turbines. Bats also used wind turbines for resting. Insects were collected at places and times when bats were observed feeding. Chironomids were dominating, but we also found many other flying species of other insect groups. Insects, but probably also crustaceans, were caught by bats in the water surface. Some terrestrial species occurred among the insects and spiders that were drifting in the air. At times we suppose that their

  2. Study on Pyroelectric Harvesters Integrating Solar Radiation with Wind Power

    Directory of Open Access Journals (Sweden)

    Chun-Ching Hsiao

    2015-07-01

    Full Text Available Pyroelectric harvesters use temperature fluctuations to generate electrical outputs. Solar radiation and waste heat are rich energy sources that can be harvested. Pyroelectric energy converters offer a novel and direct energy-conversion technology by transforming time-dependent temperatures directly into electricity. Moreover, the great challenge for pyroelectric energy harvesting lies in finding promising temperature variations or an alternating thermal loading in real situations. Hence, in this article, a novel pyroelectric harvester integrating solar radiation with wind power by the pyroelectric effect is proposed. Solar radiation is a thermal source, and wind is a dynamic potential. A disk generator is used for harvesting wind power. A mechanism is considered to convert the rotary energy of the disk generator to drive a shutter for generating temperature variations in pyroelectric cells using a planetary gear system. The optimal period of the pyroelectric cells is 35 s to harvest the stored energy, about 70 μJ, while the rotary velocity of the disk generator is about 31 RPM and the wind speed is about 1 m/s. In this state, the stored energy acquired from the pyroelectric harvester is about 75% more than that from the disk generator. Although the generated energy of the proposed pyroelectric harvester is less than that of the disk generator, the pyroelectric harvester plays a complementary role when the disk generator is inactive in situations of low wind speed.

  3. Study on Parameters Modeling of Wind Turbines Using SCADA Data

    Directory of Open Access Journals (Sweden)

    Yonglong YAN

    2014-08-01

    Full Text Available Taking the advantage of the current massive monitoring data from Supervisory Control and Data Acquisition (SCADA system of wind farm, it is of important significance for anomaly detection, early warning and fault diagnosis to build the data model of state parameters of wind turbines (WTs. The operational conditions and the relationships between the state parameters of wind turbines are complex. It is difficult to establish the model of state parameter accurately, and the modeling method of state parameters of wind turbines considering parameter selection is proposed. Firstly, by analyzing the characteristic of SCADA data, a reasonable range of data and monitoring parameters are chosen. Secondly, neural network algorithm is adapted, and the selection method of input parameters in the model is presented. Generator bearing temperature and cooling air temperature are regarded as target parameters, and the two models are built and input parameters of the models are selected, respectively. Finally, the parameter selection method in this paper and the method using genetic algorithm-partial least square (GA-PLS are analyzed comparatively, and the results show that the proposed methods are correct and effective. Furthermore, the modeling of two parameters illustrate that the method in this paper can applied to other state parameters of wind turbines.

  4. Experimental wind tunnel study of a smart sensing skin for condition evaluation of a wind turbine blade

    Science.gov (United States)

    Downey, Austin; Laflamme, Simon; Ubertini, Filippo

    2017-12-01

    Condition evaluation of wind turbine blades is difficult due to their large size, complex geometry and lack of economic and scalable sensing technologies capable of detecting, localizing, and quantifying faults over a blade’s global area. A solution is to deploy inexpensive large area electronics over strategic areas of the monitored component, analogous to sensing skin. The authors have previously proposed a large area electronic consisting of a soft elastomeric capacitor (SEC). The SEC is highly scalable due to its low cost and ease of fabrication, and can, therefore, be used for monitoring large-scale components. A single SEC is a strain sensor that measures the additive strain over a surface. Recently, its application in a hybrid dense sensor network (HDSN) configuration has been studied, where a network of SECs is augmented with a few off-the-shelf strain gauges to measure boundary conditions and decompose the additive strain to obtain unidirectional surface strain maps. These maps can be analyzed to detect, localize, and quantify faults. In this work, we study the performance of the proposed sensing skin at conducting condition evaluation of a wind turbine blade model in an operational environment. Damage in the form of changing boundary conditions and cuts in the monitored substrate are induced into the blade. An HDSN is deployed onto the interior surface of the substrate, and the blade excited in a wind tunnel. Results demonstrate the capability of the HDSN and associated algorithms to detect, localize, and quantify damage. These results show promise for the future deployment of fully integrated sensing skins deployed inside wind turbine blades for condition evaluation.

  5. Detailed Equivalent VSC-HVDC Modelling for Time Domain Harmonic Stability Studies in Wind Power Plants

    DEFF Research Database (Denmark)

    Glasdam, Jakob Bærholm; Bak, Claus Leth; Kocewiak, Lukasz Hubert

    2018-01-01

    system with 201 voltage levels, without loss of accuracy compared to conventional modelling of the converter. Harmonic stability is a core concern for both existing and future offshore wind power plants (OWPPs). A harmonic stability study will be undertaken with focus on the number of wind turbine...

  6. Reliability, availability and maintenance aspects of large-scale offshore wind farms, a concepts study

    NARCIS (Netherlands)

    Van Bussel, G.J.W.; Zaayer, M.B.

    2001-01-01

    The DOWEC projects aims at implementation of large wind turbines in large scale wind farms. part of the DOWEC project a concepts study was performed regarding the achievable reliability and availability levels. A reduction with a factor of 2 with regard to the present state of the art seems fairly

  7. Wind Turbine Acoustic Investigation: Infrasound and Low-Frequency Noise--A Case Study

    Science.gov (United States)

    Ambrose, Stephen E.; Rand, Robert W.; Krogh, Carmen M. E.

    2012-01-01

    Wind turbines produce sound that is capable of disturbing local residents and is reported to cause annoyance, sleep disturbance, and other health-related impacts. An acoustical study was conducted to investigate the presence of infrasonic and low-frequency noise emissions from wind turbines located in Falmouth, Massachusetts, USA. During the…

  8. Remote Sensing Wind and Wind Shear System.

    Science.gov (United States)

    Contents: Remote sensing of wind shear and the theory and development of acoustic doppler; Wind studies; A comparison of methods for the remote detection of winds in the airport environment; Acoustic doppler system development; System calibration; Airport operational tests.

  9. The Technical and Economic Study of Solar-Wind Hybrid Energy System in Coastal Area of Chittagong, Bangladesh

    Directory of Open Access Journals (Sweden)

    Shuvankar Podder

    2015-01-01

    Full Text Available The size optimization and economic evaluation of the solar-wind hybrid renewable energy system (RES to meet the electricity demand of 276 kWh/day with 40 kW peak load have been determined in this study. The load data has been collected from the motels situated in the coastal areas of Patenga, Chittagong. RES in standalone as well as grid connected mode have been considered. The optimal system configurations have been determined based on systems net present cost (NPC and cost of per unit energy (COE. A standalone solar-wind-battery hybrid system is feasible and economically comparable to the present cost of diesel based power plant if 8% annual capacity shortage is allowed. Grid tied solar-wind hybrid system, where more than 70% electricity contribution is from RES, is economically comparable to present grid electricity price. Moreover, grid tied RES results in more than 60% reduction in greenhouse gases emission compared to the conventional grid. Sensitivity analysis has been performed in this study to determine the effect of capital cost variation or renewable resources variation on the system economy. Simulation result of sensitivity analysis has showed that 20% reduction of installation cost results in nearly 9%–12% reductions in cost of per unit energy.

  10. Land suitability assessment for wind power plant site selection using ANP-DEMATEL in a GIS environment: case study of Ardabil province, Iran.

    Science.gov (United States)

    Azizi, Ali; Malekmohammadi, Bahram; Jafari, Hamid Reza; Nasiri, Hossein; Amini Parsa, Vahid

    2014-10-01

    Wind energy is a renewable energy resource that has increased in usage in most countries. Site selection for the establishment of large wind turbines, called wind farms, like any other engineering project, requires basic information and careful planning. This study assessed the possibility of establishing wind farms in Ardabil province in northwestern Iran by using a combination of analytic network process (ANP) and decision making trial and evaluation laboratory (DEMATEL) methods in a geographical information system (GIS) environment. DEMATEL was used to determine the criteria relationships. The weights of the criteria were determined using ANP and the overlaying process was done on GIS. Using 13 information layers in three main criteria including environmental, technical and economical, the land suitability map was produced and reclassified into 5 equally scored divisions from least suitable to most suitable areas. The results showed that about 6.68% of the area of Ardabil province is most suitable for establishment of wind turbines. Sensitivity analysis shows that significant portions of these most suitable zones coincide with suitable divisions of the input layers. The efficiency and accuracy of the hybrid model (ANP-DEMATEL) was evaluated and the results were compared to the ANP model. The sensitivity analysis, map classification, and factor weights for the two methods showed satisfactory results for the ANP-DEMATEL model in wind power plant site selection.

  11. Study of LANs access technologies in wind power system

    DEFF Research Database (Denmark)

    Wei, Mu; Chen, Zhe

    2010-01-01

    Due to the energy challenges in the world, new types of generation technologies, such as renewable energy based generators, attract great attention and are being quickly developed, which results in the dramatic developments and changes in modern power systems, the communication technologies play...... a increasingly important role in guaranteeing the power system’s stability, reliability, and security. In this paper the necessity of communication technologies employed in wind power system are introduced. According the International Standards Organization (ISO) reference 7-layered model, the communication...... power environment are explained and discussed. Furthermore the simulation of application of Ethernet in an offshore wind farm communication network by a software, OPNET, is elaborated. With the investigation of the communication technologies in this paper, the offshore wind farm SCADA system can...

  12. Study on visual detection method for wind turbine blade failure

    Science.gov (United States)

    Chen, Jianping; Shen, Zhenteng

    2018-02-01

    Start your abstract here…At present, the non-destructive testing methods of the wind turbine blades has fiber bragg grating, sound emission and vibration detection, but there are all kinds of defects, and the engineering application is difficult. In this regard, three-point slope deviation method, which is a kind of visual inspection method, is proposed for monitoring the running status of wind turbine blade based on the image processing technology. A better blade image can be got through calibration, image splicing, pretreatment and threshold segmentation algorithm. Design of the early warning system to monitor wind turbine blade running condition, recognition rate, stability and impact factors of the method were statistically analysed. The experimental results shown showed that it has highly accurate and good monitoring effect.

  13. Wind energy applications of synthetic aperture radar

    Energy Technology Data Exchange (ETDEWEB)

    Bruun Christiansen, M.

    2006-11-15

    Synthetic aperture radars (SAR), mounted on satellites or aircraft, have proven useful for ocean wind mapping. Wind speeds at the height 10 m may be retrieved from measurements of radar backscatter using empirical model functions. The resulting wind fields are valuable in offshore wind energy planning as a supplement to on site measurements, which are costly and sparse, and model wind fields, which are not fully validated. Two applications of SAR measurements in offshore wind energy planning are addressed here: the study of wind farm wake effects and the potential of using SAR winds in offshore wind resource assessment. Firstly, wind wakes behind two large offshore wind farms in Denmark Horns Rev and Nysted are identified. A region of reduced wind speed is found downstream of both wind farms from the SAR wind fields. The wake extent and magnitude depends on the wind speed, the atmospheric stability, and the fraction of turbines operating. Wind farm wake effects are detected up to 20 km downwind of the last turbine. This distance is longer than predicted by state-of-the art wake models. Wake losses are typically 10-20% near the wind farms. Secondly, the potential of using SAR wind maps in offshore wind resource assessment is investigated. The resource assessment is made through Weibull fitting to frequency observations of wind speed and requires at least 100 satellite observations per year for a given site of interest. Predictions of the energy density are very sensitive to the wind speed and the highest possible accuracy on SAR wind retrievals is therefore sought. A 1.1 m s{sup -1} deviation on the mean wind speed is found through comparison with mast measurements at Horns Rev. The accuracy on mean wind speeds and energy densities found from satellite measurements varies with different empirical model functions. Additional uncertainties are introduced by the infrequent satellite sampling at fixed times of the day. The accuracy on satellite based wind resource

  14. Betting on wind energy

    International Nuclear Information System (INIS)

    2009-11-01

    In the first part of this study, the authors try to identify whether the economical and environmental context is adapted to the wind energy development. In order to do so, they discuss wind energy as a possible answer to climate emergency, critics formulated against wind energy, the effects of the financial crisis and the opportunities offered by wind energy within this crisis. In the second part, they discuss the French context and the debates on wind energy, highlighting the importance of some parameters in the cost analysis of wind turbine, presenting the results of a sensitivity analysis, and highlighting the importance of the over-cost calculation. They assess the current development status of the French wind energy industry and underline the opportunities for the future. In the third part, they describe the development status, lever and perspectives in different countries: Germany where the development of this sector has been successful, China which is becoming a major actor, the United States which are displaying the highest growth in this area, and Denmark which is the world leader

  15. The use of Markov chains in forecasting wind speed: Matlab source code and applied case study

    Directory of Open Access Journals (Sweden)

    Ionuţ Alexandru Petre

    2017-01-01

    Full Text Available The ability to predict the wind speed has an important role for renewable energy industry which relies on wind speed forecasts in order to calculate the power a wind farm can produce in an area. There are several well-known methods to predict wind speed, but in this paper we focus on short-term wind forecasting using Markov chains. Often gaps can be found in the time series of the wind speed measurements and repeating the measurements is usually not a valid option. In this study it is shown that using Markov chains these gaps from the time series can be filled (they can be generated in an efficient way, but only when the missing data is for a short period of time. Also, the developed Matlab programms that are used in the case study, are included in the paper beeing presented and commented by the authors. In the case study data from a wind farm in Italy is used. The available data are as average wind speed at an interval of 10 minutes in the time period 11/23/2005 - 4/27/2006.

  16. Preliminary study of long-term wind characteristics of the Mexican Yucatan Peninsula

    International Nuclear Information System (INIS)

    Soler-Bientz, Rolando; Watson, Simon; Infield, David

    2009-01-01

    Mexico's Yucatan Peninsula is one of the most promising areas for wind energy development within the Latin American region but no comprehensive assessment of wind resource has been previously published. This research presents a preliminary analysis of the meteorological parameters relevant to the wind resource in order to find patterns in their long-term behaviour and to establish a foundation for subsequent research into the wind power potential of the Yucatan Peninsula. Three meteorological stations with data measured for a period between 10 and 20 years were used in this study. The monthly trends of ambient temperature, atmospheric pressure and wind speed data were identified and are discussed. The directional behaviour of the winds, their frequency distributions and the related Weibull parameters are presented. Wind power densities for the study sites have been estimated and have been shown to be relatively low (wind power class 1), though a larger number of suitable sites needs to be studied before a definitive resource evaluation can be reported.

  17. Pre- and post-construction studies of conflicts between birds and wind turbines in coastal Norway (BirdWind)

    Energy Technology Data Exchange (ETDEWEB)

    Bevanger, K.; Berntsen, F.; Clausen, S.; Dahl, E.L.; Flagstad, Oe.; Follestad, A.; Halley, D.; Hanssen, F.; Hoel, P.L.; Johnsen, L.; Kvaloey, P.; May, R.; Nygaard, T.; Pedersen, H.C.; Reitan, O.; Steinheim, Y.; Vang, R.

    2009-12-15

    The project is named Pre- and post-construction studies of conflicts between birds and wind turbines in coastal Norway (BirdWind). BirdWind is approaching its finalization; with 2010 as the last ordinary year where data-collecting activities takes place. In 2009 the project was significantly strengthened through a new PhD-position. The overall aim of the work conducted by the PhD-student is to model the future white-tailed eagle (WTE) population development based on reproduction and mortality data. Weekly searches with dogs for birds killed within the wind-power plant have been carried out throughout the year; in general searches are conducted every 7 days. 25 'primary turbines' are selected and searched together with one of two dogs. A full search of all turbines is performed at larger intervals. In 2009 31 specimens of at least 8 species have been re-corded. The most frequent victims are willow ptarmigan and WTE with 10 and 7 carcasses, respectively. Of waders 3 common snipes have been recorded. Five carcasses were recorded of hooded crow, and single carcasses of parrot crossbill, northern wheat ear, teal and mallard. Some records from earlier years have been revised as collision victims or not. Also in 2009 censuses for willow ptarmigan have been carried out in spring and autumn on Smoela and Hitra. The preliminary results do not indicate any obvious differences between the two areas, but autumn density in the wind-power plant area seems to be more stable compared to the control area. Interestingly the higher density within the wind-power plant area in autumn is evened out in spring each year, so also in spring 2009. To obtain data on habitat selection, movements, collision risks, survival of eggs, chicks and adults and general population dynamic parameters, willow ptarmigan specimen have been radio-tagged in 2008-2009. The activities regarding breeding waders and small birds (mainly passerines) have this year focused on the EIA-activities on Hitra in

  18. CubeSat Constellation Cloud Winds(C3Winds) A New Wind Observing System to Study Mesoscale Cloud Dynamics and Processes

    Science.gov (United States)

    Wu, D. L.; Kelly, M.A.; Yee, J.-H.; Boldt, J.; Demajistre, R.; Reynolds, E. L.; Tripoli, G. J.; Oman, L. D.; Prive, N.; Heidinger, A. K.; hide

    2016-01-01

    The CubeSat Constellation Cloud Winds (C3Winds) is a NASA Earth Venture Instrument (EV-I) concept with the primary objective to better understand mesoscale dynamics and their structures in severe weather systems. With potential catastrophic damage and loss of life, strong extratropical and tropical cyclones (ETCs and TCs) have profound three-dimensional impacts on the atmospheric dynamic and thermodynamic structures, producing complex cloud precipitation patterns, strong low-level winds, extensive tropopause folds, and intense stratosphere-troposphere exchange. Employing a compact, stereo IR-visible imaging technique from two formation-flying CubeSats, C3Winds seeks to measure and map high-resolution (2 km) cloud motion vectors (CMVs) and cloud geometric height (CGH) accurately by tracking cloud features within 5-15 min. Complementary to lidar wind observations from space, the high-resolution wind fields from C3Winds will allow detailed investigations on strong low-level wind formation in an occluded ETC development, structural variations of TC inner-core rotation, and impacts of tropopause folding events on tropospheric ozone and air quality. Together with scatterometer ocean surface winds, C3Winds will provide a more comprehensive depiction of atmosphere-boundary-layer dynamics and interactive processes. Built upon mature imaging technologies and long history of stereoscopic remote sensing, C3Winds provides an innovative, cost-effective solution to global wind observations with potential of increased diurnal sampling via CubeSat constellation.

  19. Spatiotemporal distribution of nitrogen dioxide within and around a large-scale wind farm – a numerical case study

    Directory of Open Access Journals (Sweden)

    J. Mo

    2017-12-01

    Full Text Available As a renewable and clean energy source, wind power has become the most rapidly growing energy resource worldwide in the past decades. Wind power has been thought not to exert any negative impacts on the environment. However, since a wind farm can alter the local meteorological conditions and increase the surface roughness lengths, it may affect air pollutants passing through and over the wind farm after released from their sources and delivered to the wind farm. In the present study, we simulated the nitrogen dioxide (NO2 air concentration within and around the world's largest wind farm (Jiuquan wind farm in Gansu Province, China using a coupled meteorology and atmospheric chemistry model WRF-Chem. The results revealed an edge effect, which featured higher NO2 levels at the immediate upwind and border region of the wind farm and lower NO2 concentration within the wind farm and the immediate downwind transition area of the wind farm. A surface roughness length scheme and a wind turbine drag force scheme were employed to parameterize the wind farm in this model investigation. Modeling results show that both parameterization schemes yield higher concentration in the immediate upstream of the wind farm and lower concentration within the wind farm compared to the case without the wind farm. We infer this edge effect and the spatial distribution of air pollutants to be the result of the internal boundary layer induced by the changes in wind speed and turbulence intensity driven by the rotation of the wind turbine rotor blades and the enhancement of surface roughness length over the wind farm. The step change in the roughness length from the smooth to rough surfaces (overshooting in the upstream of the wind farm decelerates the atmospheric transport of air pollutants, leading to their accumulation. The rough to the smooth surface (undershooting in the downstream of the wind farm accelerates the atmospheric transport of air pollutants, resulting in

  20. Preliminary study of a SAVONIUS rotor and its adaptation to a pumping system using wind energy

    Energy Technology Data Exchange (ETDEWEB)

    Lebchek, Kamel; Outtas, T.; Mesmoudi, K. [Mechanical Engineering Departement, Faculty of Engineering Sciences, University of Batna, Batna (Algeria)

    2013-07-01

    The Wind energy is an uncertain and discontinuous energy in the time, asking for no primary extraction, it is free and its capture is without serious influence on the climate and doesn't produce none poisonous residues for the atmosphere. The capture of the Wind energy is assured by the wind rotors, and among a big number of variants rotors, those with vertical axis present the advantage of construction simplicity, because they don't require any system of orientation and a simple pylon can serve like support. In this setting, our work consists in a experimental study of a rotor with vertical axis called SAVONIUS and its adaptation to a pumping system using the Wind energy. The experimental study has been achieved in subsonic wind tunnel, after realisation of a model of the SAVONIUS rotor and a special installation of transmission of the energy. The adaptation of the experimental results to a pumping system in the real case, permitted us the determination of the variation of (ıCp) and (ıı) according to the speed of wind and the establishment of a range of debits of the pump according to a range of wind speeds chosen by the meteorological evaluations of Batna region . Key words: Wind energy, SAVONIUS rotor, pumping system , coefficient of strength, transmission of energy.

  1. The Cost of Transmission for Wind Energy: A Review of Transmission Planning Studies

    Energy Technology Data Exchange (ETDEWEB)

    Mills, Andrew D.; Wiser, Ryan; Porter, Kevin

    2009-02-02

    The rapid development of wind power that the United States has experienced over the last several years has been coupled with a growing concern that wind development will require substantial additions to the nation's transmission infrastructure. Transmission is particularly important for wind power due to the locational dependence of wind resources, the relatively low capacity factor of wind plants, and the mismatch between the short lead time to build a new wind project and the longer lead time often needed to plan, permit, and construct transmission. It is clear that institutional issues related to transmission planning, siting, and cost allocation will pose major obstacles to accelerated wind power deployment, but also of concern is the potential cost of this infrastructure build out. Simply put, how much extra cost will society bear to deliver wind power to load centers? Without an answer to this question, there can be no consensus on whether or not the cost of developing transmission for wind will be a major barrier to further wind deployment, or whether the institutional barriers to transmission expansion are likely to be of more immediate concern. In this report, we review a sample of 40 detailed transmission studies that have included wind power. These studies cover a broad geographic area, and were completed from 2001-2008. Our primary goal in reviewing these studies is to develop a better understanding of the transmission costs needed to access growing quantities of wind generation. A secondary goal is to gain a better appreciation of the differences in transmission planning approaches in order to identify those methodologies that seem most able to estimate the incremental transmission costs associated with wind development. Finally, we hope that the resulting dataset and discussion might be used to inform the assumptions, methods, and results of higher-level assessment models that are sometimes used to estimate the cost of wind deployment (e.g. NEMS

  2. Worldwide wind/diesel hybrid power system study: Potential applications and technical issues

    Energy Technology Data Exchange (ETDEWEB)

    King, W.R.; Johnson, B.L. III (Science Applications International Corp., McLean, VA (USA))

    1991-04-01

    The world market potential for wind/diesel hybrid technology is a function of the need for electric power, the availability of sufficient wind resource to support wind/diesel power, and the existence of buyers with the financial means to invest in the technology. This study includes data related to each of these three factors. This study does not address market penetration, which would require analysis of application specific wind/diesel economics. Buyer purchase criteria, which are vital to assessing market penetration, are discussed only generally. Countries were screened for a country-specific market analysis based on indicators of need and wind resource. Both developed countries and less developed countries'' (LDCs) were screened for wind/diesel market potential. Based on the results of the screening, ten countries showing high market potential were selected for more extensive market analyses. These analyses provide country-specific market data to guide wind/diesel technology developers in making design decisions that will lead to a competitive product. Section 4 presents the country-specific data developed for these analyses, including more extensive wind resource characterization, application-specific market opportunities, business conditions, and energy market characterizations. An attempt was made to identify the potential buyers with ability to pay for wind/diesel technology required to meet the application-specific market opportunities identified for each country. Additionally, the country-specific data are extended to corollary opportunities in countries not covered by the study. Section 2 gives recommendations for wind/diesel research based on the findings of the study. 86 refs.

  3. Worldwide wind/diesel hybrid power system study: Potential applications and technical issues

    Science.gov (United States)

    King, W. R.; Johnson, B. L., III

    1991-04-01

    The world market potential for wind/diesel hybrid technology is a function of the need for electric power, the availability of sufficient wind resource to support wind/diesel power, and the existence of buyers with the financial means to invest in the technology. This study includes data related to each of these three factors. This study does not address market penetration, which would require analysis of application specific wind/diesel economics. Buyer purchase criteria, which are vital to assessing market penetration, are discussed only generally. Countries were screened for a country-specific market analysis based on indicators of need and wind resource. Both developed countries and less developed countries (LDCs) were screened for wind/diesel market potential. Based on the results of the screening, ten countries showing high market potential were selected for more extensive market analyses. These analyses provide country-specific market data to guide wind/diesel technology developers in making design decisions that will lead to a competitive product. Section 4 presents the country-specific data developed for these analyses, including more extensive wind resource characterization, application-specific market opportunities, business conditions, and energy market characterizations. An attempt was made to identify the potential buyers with ability to pay for wind/diesel technology required to meet the application-specific market opportunities identified for each country. Additionally, the country-specific data are extended to corollary opportunities in countries not covered by the study. Section 2 gives recommendations for wind/diesel research based on the findings of the study.

  4. Room for wind. An investigation into the possibilities for the erection of large numbers of wind turbines. Ruimte voor wind. Een studie naar de plaatsingsmogelijkheden van grote aantallen windturbines

    Energy Technology Data Exchange (ETDEWEB)

    Arkesteijn, L; Van Huis, G; Reckman, E

    1987-01-01

    The Dutch government aims to realize a wind power capacity in The Netherlands of 1000 MW in the year 2000. Environmental impacts of the erection of a large number of 200 kW and 1 MW wind turbines are studied. Four siting models have been developed in which attention is paid to environmental and economic aspects, the possibilities to introduce the electric power into the national power grid and the availability and reliability of enough wind. Noise pollution and danger for birds are to be avoided. The choice between the construction of wind parks where a number of wind turbines is concentrated in a small area or a more dispersed construction is somewhat difficult if all relevant factors are to be taken into consideration. Without government's interference the target of 1000 MW in the year 2000 will probably not be attained. It is therefore desirable to practise an active energy policy in favor of wind energy, for which many ways are possible.

  5. An experimental study of the effect of mooring systems on the dynamics of a SPAR buoy-type floating offshore wind turbine

    Directory of Open Access Journals (Sweden)

    Sinpyo Hong

    2015-05-01

    Full Text Available An experimental study of the effect of mooring systems on the dynamics of a SPAR buoy-type floating offshore wind turbine is presented. The effects of the Center of Gravity (COG, mooring line spring constant, and fair-lead location on the turbine’s motion in response to regular waves are investigated. Experimental results show that for a typical mooring system of a SPAR buoy-type Floating Offshore Wind Turbine (FOWT, the effect of mooring systems on the dynamics of the turbine can be considered negligible. However, the pitch decreases notably as the COG increases. The COG and spring constant of the mooring line have a negligible effect on the fairlead displacement. Numerical simulation and sensitivity analysis show that the wind turbine motion and its sensitivity to changes in the mooring system and COG are very large near resonant frequencies. The test results can be used to validate numerical simulation tools for FOWTs.

  6. Study on Micro Wind Generator System for Automobile

    Science.gov (United States)

    Fujimoto, Koji; Washizu, Shinsuke; Ichikawa, Tomohiko; Yukita, Kazuto; Goto, Yasuyuki; Ichiyanagi, Katsuhiro; Oshima, Takamitsu; Hayashi, Niichi; Tobi, Nobuo

    This paper proposes the micro wind generator system for automobile. This proposes system is composed of the deflector, the micro windmill, the generator, and electric storage device. Then, the effectiveness is confirmed from an examination using air blower. Therefore, new energy can be expected to be obtained by installing this system in the truck.

  7. Numerical study on small scale vertical axis wind turbine

    Directory of Open Access Journals (Sweden)

    Parra-Santos Teresa

    2016-01-01

    Full Text Available The performance of a Vertical Axis Wind Turbine (VAWT is numerically analyzed. The set-up is Hdarrieus with three straight blades airfoils NACA attached to a rotating vertical shaft. The wind turbine has solidity equals to the unity operating with wind velocity of 7 m/s. Influence of pitch angle is tested to get design tendencies. 2D, transient, Navier Stokes equations are solved using the code Ansys-Fluent. Conservation equations were solved with a Third-Order MUSCL scheme using SIMPLE to couple pressure and velocity. More than six revolutions must be simulated to get the periodic behavior. Two models of turbulence have been contrasted Realizable k-epsilon and Transition SST concluding the last one show more realistic flow features. Pitch angles of 0º, -6º and -10º have been tested with Tip Speed Ratios ranging from 0.7 and 1.6. The no null pitch angles improve the performance of the wind turbine. Instantaneous and averaged power coefficients as well as detailed flow field around the airfoils are showed.

  8. Review Space Weather and Solar Wind Studies with OWFA

    Indian Academy of Sciences (India)

    In this paper, we review the results of interplanetary scintillation (IPS) observations made with the legacy .... complex flow of solar wind at different time and spa- ..... in a step of ∼20 .... observing program with the legacy system of the ORT.

  9. Occupational Health and Industrial Wind Turbines: A Case Study

    Science.gov (United States)

    Rand, Robert W.; Ambrose, Stephen E.; Krogh, Carmen M. E.

    2011-01-01

    Industrial wind turbines (IWTs) are being installed at a fast pace globally. Researchers, medical practitioners, and media have reported adverse health effects resulting from living in the environs of IWTs. While there have been some anecdotal reports from technicians and other workers who work in the environs of IWTs, little is known about the…

  10. Wind Shear Systems Implementation Plan, Benefit/Cost Study.

    Science.gov (United States)

    1980-08-01

    not. Accordingly, the three self contained Wind Shear Systems currently being marketed by avionics manufacturers are considered to have lower relative... RESEARC { AND I’iVEIOPMEN1 The FAA research ni d development ffort has taken a threefold appro,,ch to the vind sh#ear problem. Ore. approach was to

  11. Final Report - Wind and Hydro Energy Feasibility Study - June 2011

    Energy Technology Data Exchange (ETDEWEB)

    Jim Zoellick; Richard Engel; Rubin Garcia; Colin Sheppard

    2011-06-17

    This feasibility examined two of the Yurok Tribe's most promising renewable energy resources, wind and hydro, to provide the Tribe detailed, site specific information that will result in a comprehensive business plan sufficient to implement a favorable renewable energy project.

  12. Wind Turbine Gearbox Condition Monitoring Round Robin Study - Vibration Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Sheng, S.

    2012-07-01

    The Gearbox Reliability Collaborative (GRC) at the National Wind Technology Center (NWTC) tested two identical gearboxes. One was tested on the NWTCs 2.5 MW dynamometer and the other was field tested in a turbine in a nearby wind plant. In the field, the test gearbox experienced two oil loss events that resulted in damage to its internal bearings and gears. Since the damage was not severe, the test gearbox was removed from the field and retested in the NWTCs dynamometer before it was disassembled. During the dynamometer retest, some vibration data along with testing condition information were collected. These data enabled NREL to launch a Wind Turbine Gearbox Condition Monitoring Round Robin project, as described in this report. The main objective of this project was to evaluate different vibration analysis algorithms used in wind turbine condition monitoring (CM) and find out whether the typical practices are effective. With involvement of both academic researchers and industrial partners, the project sets an example on providing cutting edge research results back to industry.

  13. Wind farm related mortality among avian migrants - a remote sensing study and model analysis

    Energy Technology Data Exchange (ETDEWEB)

    Desholm, M

    2006-11-15

    This thesis is the result of a PhD study on bird-wind farm collisions and consists of a synopsis, five published papers, one submitted manuscript and another ready for submission. The papers describe the findings from pre- and post-construction visual, radar and thermal imaging studies (1999-2006) of migrating birds at the Nysted offshore wind farm in the Baltic Sea, Denmark. This thesis poses and answers the following questions: a) what hazard factors do offshore wind farming pose to wild birds, b) how should one choose the key focal species to study, c) how can remote sensing techniques be applied to the study of bird wind farm interactions, and d) specifically, how do water birds react when approaching an offshore wind farm? The main aim of the study was the development of a predictive bird-wind farm collision model that incorporates the avoidance rate of birds at multiple scales. Out of 235,136 migrating sea ducks only 47 individuals were predicted to collide with the wind turbine rotor-blades, equivalent to an overall mean collision risk of c. 0.02%. This thesis shows the added value of modelling in supplementing sound empirical studies in accessing the effects of major human development pressures on migratory bird populations. (au)

  14. A study on evaluating the power generation of solar-wind hybrid systems in Izmir, Turkey

    Energy Technology Data Exchange (ETDEWEB)

    Ulgen, K. [Ege Univ., Solar Energy Inst., Izmir (Turkey); Hepbasli, A. [Ege Univ., Dept. of Mechanical Engineering, Izmir (Turkey)

    2003-03-15

    Turkey is abundant in terms of renewable energy resources. Residential and industrial utilization of solar energy started in the 1980s, while the first Build-Operate-Transfer (BOT) windmill park, located at Alacati, Izmir, was commissioned in 1998. Additionally, power generation through solar-wind hybrid systems has recently appeared on the Turkish market. This study investigates the wind and solar thermal power availability in Izmir, located in the western part of Turkey. Simple models were developed to determine wind, solar, and hybrid power resources per unit area. Experimental data, consisting of hourly records over a 5 yr period, 1995-1999, were measured in the Solar/Wind Meteorological Station of the Solar Energy Institute at Ege University. Correlations between solar and wind power data were carried out on an hourly, a daily, and a monthly basis. It can be concluded that possible applications of hybrid systems could be considered for the efficient utilization of these resources. (Author)

  15. Great Lakes O shore Wind Project: Utility and Regional Integration Study

    Energy Technology Data Exchange (ETDEWEB)

    Sajadi, Amirhossein [Case Western Reserve Univ., Cleveland, OH (United States); Loparo, Kenneth A. [Case Western Reserve Univ., Cleveland, OH (United States); D' Aquila, Robert [General Electric (GE), Albany, NY (United States); Clark, Kara [National Renewable Energy Lab. (NREL), Golden, CO (United States); Waligorski, Joseph G. [FirstEnergy, Akron, OH (United States); Baker, Scott [PJM Interconnection, Audubon, PA (United States)

    2016-06-30

    This project aims to identify transmission system upgrades needed to facilitate offshore wind projects as well as operational impacts of offshore generation on operation of the regional transmission system in the Great Lakes region. A simulation model of the US Eastern Interconnection was used as the test system as a case study for investigating the impact of the integration of a 1000MW offshore wind farm operating in Lake Erie into FirstEnergy/PJM service territory. The findings of this research provide recommendations on offshore wind integration scenarios, the locations of points of interconnection, wind profile modeling and simulation, and computational methods to quantify performance, along with operating changes and equipment upgrades needed to mitigate system performance issues introduced by an offshore wind project.

  16. PV-wind hybrid system performance. A new approach and a case study

    Energy Technology Data Exchange (ETDEWEB)

    Arribas, Luis; Cano, Luis; Cruz, Ignacio [Departamento de Energias Renovables, CIEMAT, Avda. Complutense 22, 28040 Madrid (Spain); Mata, Montserrat; Llobet, Ermen [Ecotecnia, Roc Boronat 78, 08005 Barcelona (Spain)

    2010-01-15

    Until now, there is no internationally accepted guideline for the measurement, data exchange and analysis of PV-Wind Hybrid Systems. As there is a need for such a tool, so as to overcome the barrier that the lack of confidence due to the absence of reliability means for the development of the market of Hybrid Systems, an effort has been made to suggest one tool for PV-Wind Hybrid Systems. The suggested guidelines presented in this work are based on the existing guidelines for PV Systems, as a PV-Wind Hybrid system can be roughly thought of as a PV System to which wind generation has been added. So, the guidelines for PV Systems are valid for the PV-Wind System, and only the part referred to wind generation should be included. This has been the process followed in this work. The proposed method is applied to a case study, the CICLOPS Project, a 5 kW PV, 7.5 kW Wind Hybrid system installed at the Isolated Wind Systems Test Site that CIEMAT owns in CEDER (Soria, Spain). This system has been fully monitored through a year and the results of the monitoring activity, characterizing the long-term performance of the system are shown in this work. (author)

  17. PV-wind hybrid system performance. A new approach and a case study

    International Nuclear Information System (INIS)

    Arribas, Luis; Cano, Luis; Cruz, Ignacio; Mata, Montserrat; Llobet, Ermen

    2010-01-01

    Until now, there is no internationally accepted guideline for the measurement, data exchange and analysis of PV-Wind Hybrid Systems. As there is a need for such a tool, so as to overcome the barrier that the lack of confidence due to the absence of reliability means for the development of the market of Hybrid Systems, an effort has been made to suggest one tool for PV-Wind Hybrid Systems. The suggested guidelines presented in this work are based on the existing guidelines for PV Systems, as a PV-Wind Hybrid system can be roughly thought of as a PV System to which wind generation has been added. So, the guidelines for PV Systems are valid for the PV-Wind System, and only the part referred to wind generation should be included. This has been the process followed in this work. The proposed method is applied to a case study, the CICLOPS Project, a 5 kW PV, 7.5 kW Wind Hybrid system installed at the Isolated Wind Systems Test Site that CIEMAT owns in CEDER (Soria, Spain). This system has been fully monitored through a year and the results of the monitoring activity, characterizing the long-term performance of the system are shown in this work. (author)

  18. Sustainable development of the wind power industry in a complex environment: a flexibility study

    International Nuclear Information System (INIS)

    Zhao, Zhen-Yu; Zhu, Jiang; Zuo, Jian

    2014-01-01

    As a new and developing green energy business in emerging economies such as China, the wind power industry chain faces some complex issues that are further compounded by turbulent internal and external environments. To deal with the complex environment, the wind power industry needs to improve its level of flexibility so that it can become more adaptable to the changing environment. Hence it is important to explore the dynamics of the wind power industry chain flexibility with respect to the ever changing environment. This study uses questionnaire surveys and expert interviews to identify the influential flexibility components of the wind power industry chain. Subsequently a fuzzy cognitive mapping (FCM) methodology was used to establish a flexibility operating mechanism model. The research found that special attention should be paid to competition flexibility, technology flexibility, and intellectual property and talent flexibility. Policies play a pivotal role in regulating the driving effects of these components of flexibility with the aim being long term sustainability of a healthy level of overall flexibility of the wind power industry chain. This should in turn facilitate the sustainable development of the industry. - Highlights: • Wind power industry shall improve flexibility to deal with complex environment. • Critical components of flexibility of wind power industry chain were identified. • An operating mechanism model for flexibility of wind power industry is proposed. • Fuzzy cognitive mapping method is employed to model the dynamics of flexibility. • Policies play a pivotal role in fostering an industry environment toward flexibility

  19. WindPACT Turbine Design Scaling Studies: Technical Area 4 - Balance-of-Station Cost; ANNUAL

    International Nuclear Information System (INIS)

    Shafer, D. A.; Strawmyer, K. R.; Conley, R. M.; Guidinger J. H.; Wilkie, D. C.; Zellman, T. F.

    2001-01-01

    DOE's Wind Partnerships for Advanced Component Technologies (WindPACT) program explores the most advanced wind-generating technologies for improving reliability and decreasing energy costs. The first step in the WindPact program is a scaling study to bound the optimum sizes for wind turbines, to define size limits for certain technologies, and to scale new technologies. The program is divided into four projects: Composite Blades for 80-120-meter Rotors; Turbine, Rotor, and Blade Logistics; Self-Erecting Tower and Nacelle Feasibility; and Balance-of-Station Cost. This report discusses balance-of-station costs, which includes the electrical power collector system, wind turbine foundations, communications and controls, meteorological equipment, access roadways, crane pads, and the maintenance building. The report is based on a conceptual 50-megawatt (MW) wind farm site near Mission, South Dakota. Cost comparisons are provided for four sizes of wind turbines: 750 kilowatt (kW), 2.5 MW, 5.0 MW, and 10.0 MW

  20. Collision sensitive niche profile of the worst affected bird-groups at wind turbine structures in the Federal State of Brandenburg, Germany.

    Science.gov (United States)

    Bose, Anushika; Dürr, Tobias; Klenke, Reinhard A; Henle, Klaus

    2018-02-28

    Biodiversity-related impacts at wind energy facilities have increasingly become a cause of conservation concern, central issue being the collision of birds. Utilizing spatial information of their carcass detections at wind turbines (WTs), we quantified the detections in relation to the metric distances of the respective turbines to different land-use types. We used ecological niche factor analysis (ENFA) to identify combinations of land-use distances with respect to the spatial allocation of WTs that led to higher proportions of collisions among the worst affected bird-groups: Buntings, Crows, Larks, Pigeons and Raptors. We also assessed their respective similarities to the collision phenomenon by checking for overlaps amongst their distance combinations. Crows and Larks showed the narrowest "collision sensitive niche"; a part of ecological niche under higher risk of collisions with turbines, followed by that of Buntings and Pigeons. Raptors had the broadest niche showing significant overlaps with the collision sensitive niches of the other groups. This can probably be attributed to their larger home range combined with their hunting affinities to open landscapes. Identification of collision sensitive niches could be a powerful tool for landscape planning; helping avoid regions with higher risks of collisions for turbine allocations and thus protecting sensitive bird populations.

  1. Experimental studies on the nature of sensitive skin.

    Science.gov (United States)

    Kligman, A M; Sadiq, Iqbal; Zhen, Yaxian; Crosby, Marilyn

    2006-11-01

    In the USA, Europe and Japan 40 to 50% of women report that they have sensitive skin, defined as abnormal sub-clinical sensory responses to drugs, cosmetics and toiletries in the absence of visible signs of irritation. Itching, burning, stinging and tightness are the commonest complaints, which mainly afflict women. Manufacturers of skin care products have made available a large variety of products which are designed for persons with sensitive skin. Such products are not required by regulatory agencies to submit evidence of safety and efficacy, allowing marketers to make claims that are often exaggerated, irrational and even preposterous. The consumer with self-assessed sensitive skin has no way of judging which products are likely to be most beneficial and least harmful. The marketplace is awash with products for which there is no evidence that the rosy claims have been substantiated by appropriate testing procedures. There is no internationally accepted consensus regarding the criteria which define sensitive skin. Many papers have been published in the last 15 years, mainly originating from industry, which express widely differing views regarding what constitutes sensitive skin. For some, any adverse reaction to a product topically applied to sensitive skin, including breakouts, redness, scaling etc., a panoply of adverse reactions which is virtually meaningless. Others include environmental factors as causative, including cold, dry wind, heat and high humidity, solar radiation, etc., which add to the manifest complexities of the subject. This is the first paper in a series which provides a comprehensive review of the subject, emphasizing the all too many controversies and confusions arising from the lack of a consensus regarding the identification, classification, epidemiology, prevalence and pathogenesis of sensitive skin. Sensitive skin is a biologic reality and not a psychological, fashionable fantasy on the part of impressionable women. There is an urgent

  2. Pre- and post-construction studies of conflicts between birds and wind turbines in coastal Norway (BirdWind)

    Energy Technology Data Exchange (ETDEWEB)

    Bevanger, K.; Berntsen, Finn; Clausen, Stig; Dahl, E.L.; Flagstad, Oe.; Follestad, A.; Halley, Duncan; Hanssen, Frank; Johnsen, L.; Kvaloey, P.; Lund-Hoel, P.; May, Roel; Nygaard, T.; Pedersen, H.C.; Reitan, O.; Roeskaft, E.; Steinheim, Y.; Stokke, B.; Vang, R.

    2011-07-01

    The BirdWind project (2007-2010) is now concluded. This report summarises the main findings. Several scientific papers are in the process of preparation for publication in international peer re-view journals; this report only provides a brief overview. The main project objective has been to study species-, site- and seasonal-specific bird mortality; and to identify vulnerable species and site-specific factors that should be considered to improve the basis for future pre- and post construction EIAs in connection with wind power-plant constructions. To reach these goals work pack-ages and sub-projects have focused on behavioural and response studies at individual and population levels, for selected model species. The white-tailed eagle has been a focal species during the studies, as several fatalities were recorded in connection with the Smoela Wind-Power Plant (SWPP) even before the project started; the SWPP has been the main arena for project fieldwork. Modelling the WTE collision risk and making a WTE population model were important elements of the project activities. The development of methodologies and technical tools for data collection and mitigating measures has also been an important part of the project. For practical convenience the project was divided into eight sub projects focusing on 1) bird mortality, 2) willow ptarmigan, 3) breeding waders and smaller passerines, 4) white-tailed eagle, 5) bird radar, 6) mitigating technology, 7) data flow and storage systems and 8) GIS, visualization and terrain modelling. Results and preliminary conclusions related to each of these sub tasks are reported. (Author)

  3. Oxygen-Independent Pressure Sensitive Paint, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — Pressure sensitive paint (PSP) systems are excellent tools for performing global pressure measurements in aerodynamic testing, especially in wind tunnel studies. The...

  4. Validity of VR Technology on the Smartphone for the Study of Wind Park Soundscapes

    Directory of Open Access Journals (Sweden)

    Tianhong YU

    2018-04-01

    Full Text Available The virtual reality of the landscape environment supplies a high level of realism of the real environment, and may improve the public awareness and acceptance of wind park projects. The soundscape around wind parks could have a strong influence on the acceptance and annoyance of wind parks. To explore this VR technology on realism and subjective responses toward different soundscapes of ambient wind parks, three different types of virtual reality on the smartphone tests were performed: aural only, visual only, and aural–visual combined. In total, 21 aural and visual combinations were presented to 40 participants. The aural and visual information used were of near wind park settings and rural spaces. Perceived annoyance levels and realism of the wind park environment were measured. Results indicated that most simulations were rated with relatively strong realism. Perceived realism was strongly correlated with light, color, and vegetation of the simulation. Most wind park landscapes were enthusiastically accepted by the participants. The addition of aural information was found to have a strong impact on whether the participant was annoyed. Furthermore, evaluation of the soundscape on a multidimensional scale revealed the key components influencing the individual’s annoyance by wind parks were the factors of “calmness/relaxation” and “naturality/pleasantness”. “Diversity” of the soundscape might correlate with perceived realism. Finally, the dynamic aural–visual stimuli using virtual reality technology could improve the environmental assessment of the wind park landscapes, and thus, provide a more comprehensible scientific decision than conventional tools. In addition, this study could improve the participatory planning process for more acceptable wind park landscapes.

  5. Opportunity study and a business plan for a wind power plant

    International Nuclear Information System (INIS)

    Nikolov, Marjan; Naumov, Risto

    2006-01-01

    This paper provides illustration of opportunity study and a business plan for utilizing the wind renewable resource for electricity production in Macedonia. The study is prepared under UNIDO recommendations for feasibility studies (see [1]) and following the IAS, by Marjan Nikolov and Risto Naumov. This is a project simulation for a small wind farm comprising 3 power plant units. We use price list from 'Proven Engineering Products Ltd' UK.

  6. Wind power and market integration, comparative study of financing schemes

    International Nuclear Information System (INIS)

    2013-10-01

    The financing scheme of renewable energies is a key factor for their development pace and cost. As some countries like France, Germany or Spain have chosen a Feed-in Tariff (FiT) scheme, there are in fact four possible financing schemes: FiT, ex-post prime, ex-ante prime, and quotas (green certificates). A market convergence is then supposed to meet two main objectives: the control of market distortions related to wind energy development, and the optimization of wind energy production with respect to market signals. The authors analyse the underlying economic challenges and the ability of financing schemes to meet these objectives within a short term horizon (2015). They present the different financing schemes, analyse the impact of three key economic factors (market distortion, production optimization, financing costs)

  7. Offshore wind; proposed study areas; Havvind; forslag til utredningsomraader

    Energy Technology Data Exchange (ETDEWEB)

    Drivenes, Arvid; Eirum, Tale; Johnson, Nils Henrik; Mindeberg, Sigrun Kavli; Lunde, Synnoeve; Undem, Linn Silje; Veggeland, Kirsti; Veie-Rosvoll, Brit; Voksoe, Astrid

    2010-10-15

    The report suggests areas that may be suitable for establishing of offshore wind power, and should be further evaluated in a strategic environmental impact assessment, as it is designed to through Proposition. No. 107 (2008-2009). The proposed areas is shown in Figure 1 Eleven of the areas suitable for fixed installations and four sites suitable for floating installations. The work of the report has been carried out by a Directorate group led by the Norwegian Water Resources and Energy Directorate. (AG)

  8. European Wind Farm Project Costs History and Projections 2008 Study

    Energy Technology Data Exchange (ETDEWEB)

    2008-10-15

    At the request of Enova (the 'Client'), Garrad Hassan and Partners Limited ('GH') has provided technical advice on capital cost expectations for wind farm developments. In summary, the work provides a survey of the present and future 5-year prognosis for costs and conditions facing developers and suppliers in the European wind power market. The report will be used as a benchmark to support tendering for future Norwegian projects. As such, it will also provide discussion of how project characteristics can influence project cost. Data Used in the Analysis GH has obtained data on the investment costs for 35 projects developed or in development in Europe. The projects represent to the extent possible the characteristics representative of potential Norwegian projects. The data used in this analysis are from actual projects in: France, Germany, Hungary, Ireland, Italy, Northern Ireland, Portugal, Scotland, Spain and Wales. The turbine capacities represented in the data are typically 2 MW or above, except in one case where a mix of turbines sizes was used at the project. GH highlights that because of high demand for turbines, the main manufacturers have recently been offering to meet delivery schedules for new orders from late 2010. For new tenders it is likely that delivery time frames offered will now be for 2011 deliveries. As a result of the current 'Seller's Market', production capacity typically relates directly to the number of turbines sold in the year; therefore for 2007 the annual production capacity was approximately 22 GW. GH is aware that turbine suppliers across the market are working to increase their production capacity in order to ease the pressure on the market, however, there are bottlenecks through the supply chain at the sub component level. As a result, increases in production capacity will likely remain at a relatively steady state in the short term. Energy Assessment The energy assessment of a project is the area

  9. Wind Energy Applications for Municipal Water Services: Opportunities, Situation Analyses, and Case Studies; Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Flowers, L.; Miner-Nordstrom, L.

    2006-01-01

    As communities grow, greater demands are placed on water supplies, wastewater services, and the electricity needed to power the growing water services infrastructure. Water is also a critical resource for thermoelectric power plants. Future population growth in the United States is therefore expected to heighten competition for water resources. Many parts of the United States with increasing water stresses also have significant wind energy resources. Wind power is the fastest-growing electric generation source in the United States and is decreasing in cost to be competitive with thermoelectric generation. Wind energy can offer communities in water-stressed areas the option of economically meeting increasing energy needs without increasing demands on valuable water resources. Wind energy can also provide targeted energy production to serve critical local water-system needs. The research presented in this report describes a systematic assessment of the potential for wind power to support water utility operation, with the objective to identify promising technical applications and water utility case study opportunities. The first section describes the current situation that municipal providers face with respect to energy and water. The second section describes the progress that wind technologies have made in recent years to become a cost-effective electricity source. The third section describes the analysis employed to assess potential for wind power in support of water service providers, as well as two case studies. The report concludes with results and recommendations.

  10. Different Shades of Green: A Case Study of Support for Wind Farms in the Rural Midwest

    Science.gov (United States)

    Mulvaney, Kate K.; Woodson, Patrick; Prokopy, Linda Stalker

    2013-05-01

    Benton County, in north-central Indiana, USA has successfully sited more than 500 turbines. To understand Benton County's acceptance of wind farms, a holistic case study was conducted that included a document review, a survey of local residents and interviews with key stakeholders. Survey questionnaires were sent to 750 residents asking questions about attitudes toward the wind farms, perceived benefits and impacts from the wind farms, environmental attitudes, and demographic information. Key stakeholders were also interviewed for a deeper understanding of the historical timeline and community acceptance of the wind farm development. While there is limited opposition to the turbines, on the whole the community presents a front of acceptance. Financial, rather than environmental, benefits are the main reason for the acceptance. Although significant in other case studies, transparency and participation do not play a large role in Benton County's acceptance. Most residents are not concerned with either visual impacts or noise from the wind turbines. More concrete benefits to the community, such as reduced energy bills for county residents, could help to extend acceptance even further within the community. Although there are concerns about the acceptance of wind farms and the impacts of those farms on local residents in both peer-reviewed literature and popular media, we found little evidence of those concerns in Benton County. Instead, we found Benton County to be a community largely accepting of wind farms.

  11. Wind farm related mortality among avian migrants - a remote sensing study and model analysis

    DEFF Research Database (Denmark)

    Desholm, M.

    ,136 migrating sea ducks only 47 individuals were predicted to collide with the wind turbine rotor-blades, equivalent to an overall mean collision risk of c. 0.02%. This thesis shows the added value of modelling in supplementing sound empirical studies in accessing the effects of major human development......This thesis is the result of a PhD study on bird-wind farm collisions and consists of a synopsis, five published papers, one submitted manuscript and another ready for submission. The papers describe the fi ndings from pre- and post-construction visual, radar and thermal imaging studies (1999......-2006) of migrating birds at the Nysted offshore wind farm in the Baltic Sea, Denmark. This thesis poses and answers the following questions: a) what hazard factors do offshore wind farming pose to wild birds, b) how should one choose the key focal species to study, c) how can remote sensing techniques be applied...

  12. Experimental Vision Studies of Flow and Structural Effects on Wind Turbines

    DEFF Research Database (Denmark)

    Najafi, Nadia

    In the present thesis, two modern vision technologies are developed and used to study wind turbines: 1- Stereo vision to study vibrations and dynamics of the Vertical Axes Wind Turbine (VAWT) via operational modal analysis (OMA) 2- Background-oriented Schlieren (BOS) method to study the tip...... vortices that are shed from a Horizontal Axis Wind Turbine (HAWT) blades The thesis starts with an introduction to the stereo vision and OMA and is followed by two practical implementations of the basics derived in the introduction. In the first experiment, we developed the image processing tools...... a Nordtank horizontal axis wind turbine based on the density gradient in the vortex. The BOS method does not need complicated equipment such as special cameras or seeded flow, which makes it a convenient method to study large scale flows. However, the challenging part in the current case is the small...

  13. Lewis Research Center studies of multiple large wind turbine generators on a utility network

    Science.gov (United States)

    Gilbert, L. J.; Triezenberg, D. M.

    1979-01-01

    A NASA-Lewis program to study the anticipated performance of a wind turbine generator farm on an electric utility network is surveyed. The paper describes the approach of the Lewis Wind Energy Project Office to developing analysis capabilities in the area of wind turbine generator-utility network computer simulations. Attention is given to areas such as, the Lewis Purdue hybrid simulation, an independent stability study, DOE multiunit plant study, and the WEST simulator. Also covered are the Lewis mod-2 simulation including analog simulation of a two wind turbine system and comparison with Boeing simulation results, and gust response of a two machine model. Finally future work to be done is noted and it is concluded that the study shows little interaction between the generators and between the generators and the bus.

  14. Performance of the CORDEX regional climate models in simulating offshore wind and wind potential

    Science.gov (United States)

    Kulkarni, Sumeet; Deo, M. C.; Ghosh, Subimal

    2018-03-01

    This study is oriented towards quantification of the skill addition by regional climate models (RCMs) in the parent general circulation models (GCMs) while simulating wind speed and wind potential with particular reference to the Indian offshore region. To arrive at a suitable reference dataset, the performance of wind outputs from three different reanalysis datasets is evaluated. The comparison across the RCMs and their corresponding parent GCMs is done on the basis of annual/seasonal wind statistics, intermodel bias, wind climatology, and classes of wind potential. It was observed that while the RCMs could simulate spatial variability of winds, well for certain subregions, they generally failed to replicate the overall spatial pattern, especially in monsoon and winter. Various causes of biases in RCMs were determined by assessing corresponding maps of wind vectors, surface temperature, and sea-level pressure. The results highlight the necessity to carefully assess the RCM-yielded winds before using them for sensitive applications such as coastal vulnerability and hazard assessment. A supplementary outcome of this study is in form of wind potential atlas, based on spatial distribution of wind classes. This could be beneficial in suitably identifying viable subregions for developing offshore wind farms by intercomparing both the RCM and GCM outcomes. It is encouraging that most of the RCMs and GCMs indicate that around 70% of the Indian offshore locations in monsoon would experience mean wind potential greater than 200 W/m2.

  15. Prediction of tropical cyclone over North Indian Ocean using WRF model: sensitivity to scatterometer winds, ATOVS and ATMS radiances

    KAUST Repository

    Dodla, Venkata B.; Srinivas, Desamsetti; Dasari, Hari Prasad; Gubbala, Chinna Satyanarayana

    2016-01-01

    prediction with least errors less than 100 km up to 60 hours and producing pre-deepening and deepening periods accurately. The Control and SCAT wind assimilation experiments have shown good track but the errors were 150-200 km and gradual deepening from

  16. Estimating near-shore wind resources

    DEFF Research Database (Denmark)

    Floors, Rogier Ralph; Hahmann, Andrea N.; Peña, Alfredo

    An evaluation and sensitivity study using the WRF mesoscale model to estimate the wind in a coastal area is performed using a unique data set consisting of scanning, profiling and floating lidars. The ability of the WRF model to represent the wind speed was evaluated by running the model for a four...... grid spacings were performed for each of the two schemes. An evaluation of the wind profile using vertical profilers revealed small differences in modelled mean wind speed between the different set-ups, with the YSU scheme predicting slightly higher mean wind speeds. Larger differences between...... the different simulations were observed when comparing the root-mean-square error (RMSE) between modelled and measured wind, with the ERA interim-based simulations having the lowest errors. The simulations with finer horizontal grid spacing had a larger MSE. Horizontal transects of mean wind speed across...

  17. Wind energy generation for electric power production, preliminary studies. Part I

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, A

    1976-03-01

    Studies of wind power generation done by SAAB-Scania during 1975 are described. The project deals with generation of electricity for delivery to the transmission system. Both plants with horizontal axis and plants with vertical axis have been studied. A projected pilot plant with a rotor of 18 meter and an effect of 50 kW at 10 m/s wind velocity is described. Suggestions are made for a continuation of the project.

  18. Wind-direction analysis in coastal mountainous sites: An experimental study within the Gulf of Corinth, Greece

    International Nuclear Information System (INIS)

    Xydis, G.

    2012-01-01

    Highlights: ► Focus was given to the forced airflow around mountains and the effect on wind profile. ► WAsP model correlated measured and predicted wind directions in 4 coastal areas. ► The difference between simulated and measured values was always less than 8.35%. ► The clear forefront, distance from the mast and the shore influences the wind rose. - Abstract: The wind potential around several coastal areas within the Gulf of Corinth has been studied and an experimental analysis implemented accentuates the level of significance that local winds have in wind farm development and planning. The purpose of this study was to examine wind direction of coastal areas based on field measurements and correlate the results with ruggedness and distance. Four coastal mountainous areas, situated within the Gulf of Corinth, were examined and simulated results were compared to measurements aiming in explaining substantially the wind direction profile. Understanding wind flow interdependent not only from local wind, but also in the wider area of large mountains masses is of great importance for estimating wind resource in rough coastal terrain. In the present paper wind resource analysis results impose new views on the relation among masts’ horizontal distance, difference of ruggedness index, and wind direction in coastal sites.

  19. Stochastic Optimization Model to STudy the Operational Impacts of High Wind Penetrations in Ireland

    DEFF Research Database (Denmark)

    Meibom, Peter; Barth, R.; Hasche, B.

    2011-01-01

    A stochastic mixed integer linear optimization scheduling model minimizing system operation costs and treating load and wind power production as stochastic inputs is presented. The schedules are updated in a rolling manner as more up-to-date information becomes available. This is a fundamental...... change relative to day-ahead unit commitment approaches. The need for reserves dependent on forecast horizon and share of wind power has been estimated with a statistical model combining load and wind power forecast errors with scenarios of forced outages. The model is used to study operational impacts...

  20. Some studies of zonal and meridional wind characteristics at low latitude Indian stations

    Science.gov (United States)

    Nagpal, O. P.; Kumar, S.

    1985-12-01

    At the beginning of the Indian Middle Atmosphere Programme (IMAP), it was decided that the preparation of consolidation reports of already available parameters for the middle atmosphere would be useful. Atmospheric wind data obtained by rockets and balloons constituted one such parameter which had to be consolidated. The present paper summaries the results of this consolidation study. Both zonal and meridional components of winds at four low latitude Indian stations namely Thumba, Shar, Hyderabad, and Balasore, have been analyzed to yield reference wind profiles for each month. The montly mean values have been used to bring out the amplitudes and phases of the annual, semiannual and quasi-biennial oscillations.

  1. Study on Modelling Standardization of Double-fed Wind Turbine and Its Application

    Directory of Open Access Journals (Sweden)

    Li Xiang

    2016-01-01

    Full Text Available Based on the standardized modelling of the International Modelling Team, study on double-fed induction generator (DFIG wind turbine is processed in this paper, aiming at capability of universally and reasonably reflecting key performance related to large scale system analysis. The standardized model proposed is of high degree of structural modularity, easy functional extension and universalization of control strategy and signal. Moreover, it is applicable for wind turbines produced by different manufacturers through model parameter adjustment. The complexity of the model can meet both needs of grid-connected characteristic simulation of wind turbine and large scale power system simulation.

  2. Some studies of zonal and meridional wind characteristics at low latitude Indian stations

    Science.gov (United States)

    Nagpal, O. P.; Kumar, S.

    1985-01-01

    At the beginning of the Indian Middle Atmosphere Programme (IMAP), it was decided that the preparation of consolidation reports of already available parameters for the middle atmosphere would be useful. Atmospheric wind data obtained by rockets and balloons constituted one such parameter which had to be consolidated. The present paper summaries the results of this consolidation study. Both zonal and meridional components of winds at four low latitude Indian stations namely Thumba, Shar, Hyderabad, and Balasore, have been analyzed to yield reference wind profiles for each month. The montly mean values have been used to bring out the amplitudes and phases of the annual, semiannual and quasi-biennial oscillations.

  3. Effects of wind shear on the consequence model of the reactor safety study

    International Nuclear Information System (INIS)

    Sprung, J.L.; Church, H.W.

    1977-01-01

    The effects of explicit incorporation of wind shear into the consequence model of the Reactor Safety study have been investigated. The integral of exposure (X/Q) over area is unchanged by directional shear and decreased by speed shear. Consequence model predictions of early fatalities are always decreased by wind shear. Where early fatalities are decreased, survivors are subject to latent effects and, therefore, latent effects increase. However, aggregate early fatalities and latent effects always are decreased. Because the magnitude of these changes is within the present uncertainties of the consequence model, explicit incorporation of wind shear in the consequence model is not now warranted

  4. Anti-deuteron sensitivity studies at LHCb

    CERN Multimedia

    Baker, Sophie Katherine

    2018-01-01

    Measurements of anti-deuterons in collider experiments can help to reduce systematic uncertainties in indirect searches for dark matter. Two predominant unknowns in these searches are the production of secondary anti-deuterons in the cosmos from spallation processes, and anti-deuteron production from annihilating dark matter. LHCb is a forward spectrometer on the LHC ring, designed to measure b-hadron decays from high energy proton-proton collisions. With the detector's excellent particle identification capabilities, deuteron and anti-deuteron measurements at LHCb could help to parametrise the two cosmological processes. Recent studies of (anti-)deuteron identification at LHCb and the prospects for measuring prompt (anti-)deuterons from pp-collisions will be presented, as well as a working analysis of b-baryrons decaying to deuterons.

  5. Study on offshore wind farm wakes based on Envisat ASAR, Radarsat-2 and Sentinel-1

    DEFF Research Database (Denmark)

    Hasager, Charlotte Bay; Badger, Merete; Badger, Jake

    energy production in clustered wind farms. Envisat ASAR, Radarsat-2 and Sentinel-1 are used in the study covering wind farms in the North Sea and Kattegat Strait. Three types of analysis are performed. The first is a case based on a Radarsat-2 Scan-SAR wide VV scene (30th April 2013 at 17:41 UTC...... is rotation of the data such that all scenes are aligned with inflow and downstream (wake region) based on the wind direction in the wind field maps. The rotation is done at 1 degree intervals. The data from rotated circles (not geo-collocated) are normalized with the winds at the side-lobes. Side......-lobes are regions expected to be undisturbed by the wind farm wake. The key result of the analysis is the significant wind wake deficit at the inner circle, decreasing at outer circles, as expected. The SAR-based results strongly support the wake model results based on PARK and WRF (Hasager et al. 2015b). The third...

  6. Estimating the wake deflection downstream of a wind turbine in different atmospheric stabilities: an LES study

    Directory of Open Access Journals (Sweden)

    L. Vollmer

    2016-09-01

    Full Text Available An intentional yaw misalignment of wind turbines is currently discussed as one possibility to increase the overall energy yield of wind farms. The idea behind this control is to decrease wake losses of downstream turbines by altering the wake trajectory of the controlled upwind turbines. For an application of such an operational control, precise knowledge about the inflow wind conditions, the magnitude of wake deflection by a yawed turbine and the propagation of the wake is crucial. The dependency of the wake deflection on the ambient wind conditions as well as the uncertainty of its trajectory are not sufficiently covered in current wind farm control models. In this study we analyze multiple sources that contribute to the uncertainty of the estimation of the wake deflection downstream of yawed wind turbines in different ambient wind conditions. We find that the wake shapes and the magnitude of deflection differ in the three evaluated atmospheric boundary layers of neutral, stable and unstable thermal stability. Uncertainty in the wake deflection estimation increases for smaller temporal averaging intervals. We also consider the choice of the method to define the wake center as a source of uncertainty as it modifies the result. The variance of the wake deflection estimation increases with decreasing atmospheric stability. Control of the wake position in a highly convective environment is therefore not recommended.

  7. Carolina Offshore Wind Integration Case Study: Phases I and II Final Technical Report

    Energy Technology Data Exchange (ETDEWEB)

    Fallon, Christopher [Duke Energy Business Services, LLC, Charlotte, NC (United States); Piper, Orvane [Duke Energy Business Services, LLC, Charlotte, NC (United States); Hazelip, William [Duke Energy Business Services, LLC, Charlotte, NC (United States); Zhao, Yishan [Duke Energy Business Services, LLC, Charlotte, NC (United States); Salvador, Lisa [Duke Energy Business Services, LLC, Charlotte, NC (United States); Pruitt, Tom [Duke Energy Business Services, LLC, Charlotte, NC (United States); Peterson, Jeffrey [Duke Energy Business Services, LLC, Charlotte, NC (United States); Ashby, Rebecca [Duke Energy Business Services, LLC, Charlotte, NC (United States); Pierce, Bob [Duke Energy Business Services, LLC, Charlotte, NC (United States); Burner, Bob [Duke Energy Business Services, LLC, Charlotte, NC (United States); Daniel, John [ABB, Inc., Cary, NC (United States); Zhu, Jinxiang [ABB, Inc., Cary, NC (United States); Moore, Maria [ABB, Inc., Cary, NC (United States); Liu, Shu [ABB, Inc., Cary, NC (United States); Pennock, Ken [AWS Truepower, LLC, Albany, NY (United States); Frank, Jaclyn [AWS Truepower, LLC, Albany, NY (United States); Ibanez, Eduardo [National Renewable Energy Lab. (NREL), Golden, CO (United States); Heaney, Michael [National Renewable Energy Lab. (NREL), Golden, CO (United States); Bloom, Aaron [National Renewable Energy Lab. (NREL), Golden, CO (United States); Zhang, Yingchen [National Renewable Energy Lab. (NREL), Golden, CO (United States); Elliott, Dennis [National Renewable Energy Lab. (NREL), Golden, CO (United States); Seim, Harvey E. [Univ. of North Carolina, Chapel Hill, NC (United States)

    2015-04-30

    Duke Energy performed a phase 1 study to assess the impact of offshore wind development in the waters off the coasts of North Carolina and South Carolina. The study analyzed the impacts to the Duke Energy Carolinas electric power system of multiple wind deployment scenarios. Focusing on an integrated utility system in the Carolinas provided a unique opportunity to assess the impacts of offshore wind development in a region that has received less attention regarding renewables than others in the US. North Carolina is the only state in the Southeastern United States that currently has a renewable portfolio standard (RPS) which requires that 12.5% of the state’s total energy requirements be met with renewable resources by 2021. 12.5% of the state’s total energy requirements in 2021 equates to approximately 17,000 GWH of energy needed from renewable resources. Wind resources represent one of the ways to potentially meet this requirement. The study builds upon and augments ongoing work, including a study by UNC to identify potential wind development sites and the analysis of impacts to the regional transmission system performed by the NCTPC, an Order 890 planning entity of which DEC is a member. Furthermore, because the region does not have an independent system operator (ISO) or regional transmission organization (RTO), the study will provide additional information unique to non-RTO/ISO systems. The Phase 2 study builds on the results of Phase 1 and investigates the dynamic stability of the electrical network in Task 4, the operating characteristics of the wind turbines as they impact operating reserve requirements of the DEC utility in Task 5, and the production cost of integrating the offshore wind resources into the DEC generation fleet making comparisons to future planned operation without the addition of the wind resources in Task 6.

  8. Feasibility study of 5MW superconducting wind turbine generator

    DEFF Research Database (Denmark)

    Abrahamsen, Asger Bech; Jensen, Bogi Bech; Seiler, E.

    2011-01-01

    The feasibility of installing a direct drive superconducting generator in the 5MW reference offshore wind turbine of the National Renewable Energy Laboratory (NREL) has been examined. The engineering current densities Je obtained in a series of race track coils have been combined with magnetization...... measurements to estimate the properties of suitable field coils for a synchronous generator, which is more light weight than the conventional used combination of a gear box and a fast rotating generator. An analytical model and finite element simulations have been used to estimate the active mass of generators...

  9. The visual impact of Taff Ely wind farm - a case study using GIS

    International Nuclear Information System (INIS)

    Kidner, D.B.

    1997-01-01

    This paper describes a project being undertaken to validate the performance of a Geographical Information System (GIS) being developed to predict, quantify and qualify the visual impact of proposed wind farm developments. In order to determine the optimal choice of terrain data model, elevation and topographic data sets, and visibility algorithms, a validation study for the Taff Ely Wind Farm has been commissioned. The issues involved in calculating and presenting visual impact are discussed, whilst a methodology for verifying the results is also described. Existing methods for presenting for visual impact of wind farms are limited and susceptible to error, whilst the interpretation of the results can often do more harm than good. The use of GIS to visualise the probable impacts is illustrated to add meaning to the results of a wind farm visibility study. (author)

  10. Impacts of climate change on wind energy resources in France: a regionalization study

    International Nuclear Information System (INIS)

    Najac, J.

    2008-11-01

    In this work, we study the impact of climate change on surface winds in France and draw conclusions concerning wind energy resources. Because of their coarse spatial resolution, climate models cannot properly reproduce the spatial variability of surface winds. Thus, 2 down-scaling methods are developed in order to regionalize an ensemble of climate scenarios: a statistical method based on weather typing and a statistic-dynamical method that resorts to high resolution mesoscale modelling. By 2050, significant but relatively small changes are depicted with, in particular, a decrease of the wind speed in the southern and an increase in the northern regions of France. The use of other down-scaling methods enables us to study several uncertainty sources: it appears that most of the uncertainty is due to the climate models. (author)

  11. Metric of the 2–6 day sea-surface temperature response to wind stress in the Tropical Pacific and its sensitivity to the K-Profile Parameterization of vertical mixing

    KAUST Repository

    Wagman, Benjamin M.

    2014-05-04

    Uncertainty in wind forcing has long hampered direct tests of ocean model output against observations for the purpose of refining the boundary layer K-Profile Parameterization (KPP) of oceanic vertical mixing. Considered here is a short-term metric that could be sensitive to the ways in which the KPP directly affects the adjustment of sea surface temperatures for a given change in wind stress. In particular a metric is developed based on the lagged correlation between the 2–6 day filtered wind stress and sea surface temperature. The metric is normalized by estimated observational and model uncertainties such that the significance of differences may be assessed. For this purpose multiple wind reanalysis products and their blended combinations were used to represent the range of forcing uncertainty, while perturbed KPP parameter model runs explore the sensitivity of the metric to the parameterization of vertical mixing. The correlation metric is sensitive to perturbations to most KPP parameters, in ways that accord with expectations, although only a few parameters show a sensitivity on the same order as the sensitivity to switching between wind products. This suggests that uncertainties in wind forcing continue to be a significant limitation for applying direct observational tests of KPP physics. Moreover, model correlations are biased high, suggesting that the model lacks or does not resolve sources of variability on the 2–6 day time scale.

  12. Metric of the 2–6 day sea-surface temperature response to wind stress in the Tropical Pacific and its sensitivity to the K-Profile Parameterization of vertical mixing

    KAUST Repository

    Wagman, Benjamin M.; Jackson, Charles S.; Yao, Fengchao; Zedler, Sarah; Hoteit, Ibrahim

    2014-01-01

    Uncertainty in wind forcing has long hampered direct tests of ocean model output against observations for the purpose of refining the boundary layer K-Profile Parameterization (KPP) of oceanic vertical mixing. Considered here is a short-term metric that could be sensitive to the ways in which the KPP directly affects the adjustment of sea surface temperatures for a given change in wind stress. In particular a metric is developed based on the lagged correlation between the 2–6 day filtered wind stress and sea surface temperature. The metric is normalized by estimated observational and model uncertainties such that the significance of differences may be assessed. For this purpose multiple wind reanalysis products and their blended combinations were used to represent the range of forcing uncertainty, while perturbed KPP parameter model runs explore the sensitivity of the metric to the parameterization of vertical mixing. The correlation metric is sensitive to perturbations to most KPP parameters, in ways that accord with expectations, although only a few parameters show a sensitivity on the same order as the sensitivity to switching between wind products. This suggests that uncertainties in wind forcing continue to be a significant limitation for applying direct observational tests of KPP physics. Moreover, model correlations are biased high, suggesting that the model lacks or does not resolve sources of variability on the 2–6 day time scale.

  13. Bird impact study on the 10 MW wind farm of La Pena (Tarifa)

    International Nuclear Information System (INIS)

    Cererols, N.; Martinez, A.; Ferrer, M.

    1996-01-01

    This paper shows the conclusions of a 16 month study of the possible impacts on the local and migrating population of birds of a wind farm located in the passageway of migrating birds between Africa and Europe. On the whole, the wind farm did not prove to represent an important impact on the birds present in its surroundings and, on the contrary, created a new habitat for some species not present in adjacent areas. (author)

  14. The Feasibility Study on Thermal Loading Control of Wind Power Converters with a Flexible Switching Frequency

    DEFF Research Database (Denmark)

    Qin, Zian; Wang, Huai; Blaabjerg, Frede

    2015-01-01

    Thermal loading of wind power converters is critical to their reliability performance. Especially for IGBT modules applied in a converter, both of the mean value and variation of the junction temperature have significant impact on the lifetime. Besides other strategies to reduce the thermal loadi...... the temperature fluctuations due to wind speed variations. The trade-off between the reduced amplitude of temperature fluctuations and the additional power losses that may be introduced is quantitatively studied....

  15. A numerical study on the flow upstream of a wind turbine on complex terran

    DEFF Research Database (Denmark)

    Meyer Forsting, Alexander Raul; Bechmann, Andreas; Troldborg, Niels

    2016-01-01

    The interaction of a wind turbine with the upstream flow-field in complex and flat terrain is studied using Reynolds-averaged Navier-Stokes (RANS) simulations with a two equation turbulence closure. The complex site modelled is Perdigao (Portugal), where a turbine is located on one of two parallel...... the wind turbine wake trajectory which in turn governs the orientation of the induction zone...

  16. The role of taxation policy and incentives in wind-based distributed generation projects viability. Ontario case study

    International Nuclear Information System (INIS)

    Albadi, M.H.; El-Saadany, E.F.

    2009-01-01

    Taxation policy and incentives play a vital role in wind-based distributed generation projects viability. In this paper, a thorough techno-economical evaluation of wind-based distributed generation projects is conducted to investigate the effect of taxes and incentives in the economic viability of investments in this sector. This paper considers the effects of Provincial income taxes, capital cost allowance (CCA), property taxes, and wind power production Federal incentives. The case study is conducted for different wind turbines and wind speed scenarios. Given turbine and wind speed data, the Capacity Factor (CF) of each turbine and wind speed scenario was calculated. Net Present Value (NPV) and Internal Rate of Return (IRR) for different scenarios were then used to assess the project's viability considering Ontario Standard Offer Program (SOP) for wind power. (author)

  17. CFD Study on Aerodynamic Power Output Changes with Inter-Turbine Spacing Variation for a 6 MW Offshore Wind Farm

    Directory of Open Access Journals (Sweden)

    Nak Joon Choi

    2014-11-01

    Full Text Available This study examined the aerodynamic power output change of wind turbines with inter-turbine spacing variation for a 6 MW wind farm composed of three sets of 2 MW wind turbines using computational fluid dynamics (CFD. The wind farm layout design is becoming increasingly important as the use of wind energy is steadily increasing. Among the many wind farm layout design parameters, the inter-turbine spacing is a key factor in the initial investment cost, annual energy production and maintenance cost. The inter-turbine spacing should be determined to maximize the annual energy production and minimize the wake effect, turbulence effect and fatigue load during the service lifetime of wind turbines. Therefore, some compromise between the aerodynamic power output of wind turbines and the inter-turbine spacing is needed. An actuator disc model with the addition of a momentum source was not used, and instead, a full 3-dimensional model with a tower and nacelle was used for CFD analysis because of its great technical significance. The CFD analysis results, such as the aerodynamic power output, axial direction wind speed change, pressure drop across the rotor of wind turbine, and wind speed deficit due to the wake effect with inter-turbine spacing variation, were studied. The results of this study can be applied effectively to wind farm layout design and evaluation.

  18. Cape Blanco wind energy feasibility study. Terrestrial ecology

    Science.gov (United States)

    1986-04-01

    The project site is a series of grassland bench terraces on a bluff above the Pacific Ocean. Because the site has a long history of use for sheep grazing, the vegetation is mainly pasture grasses (64 percent of the site), with patches of mixed forest cover (26 percent), and wetlands (10 percent) in the ravine dividing the site. Because of the open nature of the site, the proposed arrangement of the wind turbines and relatively little need for site modification, there are few environmental concerns. The main concerns are the potential for bird collisions with the turbines and associated apparatus and threatened and endangered bird species. The expected impacts of the project on vegetation, mammals, amphibians, reptiles, and fish have been determined to be minor. A series of calculations were made using formulas from the literature to estimate bird kills from collisions with the wind turbines and associated apparatus. Less than one-tenth of 1 percent of the vulnerable migrating bird population was determined to be subject to death by collision. Thus, impacts to birds were also determined to be insignificant. The other major concern is the potential impacts of the project on five species of birds from the area that are recognized as threatened or endangered. The site provides no unique or especially important habitat for any of the five species. The likelihood of project impacts to any of them is low.

  19. Aeroelastic Uncertainty Quantification Studies Using the S4T Wind Tunnel Model

    Science.gov (United States)

    Nikbay, Melike; Heeg, Jennifer

    2017-01-01

    This paper originates from the joint efforts of an aeroelastic study team in the Applied Vehicle Technology Panel from NATO Science and Technology Organization, with the Task Group number AVT-191, titled "Application of Sensitivity Analysis and Uncertainty Quantification to Military Vehicle Design." We present aeroelastic uncertainty quantification studies using the SemiSpan Supersonic Transport wind tunnel model at the NASA Langley Research Center. The aeroelastic study team decided treat both structural and aerodynamic input parameters as uncertain and represent them as samples drawn from statistical distributions, propagating them through aeroelastic analysis frameworks. Uncertainty quantification processes require many function evaluations to asses the impact of variations in numerous parameters on the vehicle characteristics, rapidly increasing the computational time requirement relative to that required to assess a system deterministically. The increased computational time is particularly prohibitive if high-fidelity analyses are employed. As a remedy, the Istanbul Technical University team employed an Euler solver in an aeroelastic analysis framework, and implemented reduced order modeling with Polynomial Chaos Expansion and Proper Orthogonal Decomposition to perform the uncertainty propagation. The NASA team chose to reduce the prohibitive computational time by employing linear solution processes. The NASA team also focused on determining input sample distributions.

  20. A Numerical Study on a Vertical-Axis Wind Turbine with Inclined Arms

    Directory of Open Access Journals (Sweden)

    Agostino De Marco

    2014-01-01

    Full Text Available This work focuses on a particular type of vertical-axis wind turbine, in which a number of inclined arms with airfoil-shaped cross-sections are mounted to connect the principal blades to their hub. While the majority of the known studies on vertical-axis turbines is devoted to the role of principal blades, in most of the cases without taking into account other parts of the wind turbine, the objective of this work is to investigate the effect of uncommon arm geometries, such as the inclined arms. The inclined arms are known to have a potentially beneficial role in the power extraction from the wind current but, due to the complexity of the phenomena, the investigation on aerodynamics of this type of turbine is often impossible through analytical models, such as blade-element momentum theory. It turns out that adequate studies can only be carried out by wind tunnel experiments or CFD simulations. This work presents a methodical CFD study on how inclined arms can be used on a selected wind turbine configuration to harvest additional power from the wind. The turbine configuration, geometry, and some fundamental definitions are introduced first. Then an in-depth CFD analysis is presented and discussed.

  1. Pre- and post-construction studies of conflicts between birds and wind turbines in coastal Norway (BirdWind). Report on findings 2007-2010

    OpenAIRE

    Bevanger, Kjetil Modolv; Berntsen, Finn Erik Harald; Clausen, Stig Morten; Dahl, Espen Lie; Flagstad, Øystein; Follestad, Arne; Halley, Duncan John; Hanssen, Frank Ole; Johnsen, Lars; Kvaløy, Pål; Lund-Hoel, Pernille*; May, Roelof Frans; Nygård, Torgeir; Pedersen, Hans-Christian; Reitan, Ole

    2011-01-01

    Bevanger, K., Berntsen, F., Clausen, S., Dahl, E.L., Flagstad, Ø. Follestad, A., Halley, D., Hanssen, F., Johnsen, L., Kvaløy, P., Lund-Hoel, P., May, R., Nygård, T., Pedersen, H.C., Reitan, O., Røskaft, E., Steinheim, Y., Stokke, B. & Vang, R. 2010. Pre- and post-construction studies of conflicts between birds and wind turbines in coastal Norway (BirdWind). Report on findings 2007-2010. – NINA Report 620. 152 pp. The BirdWind project (2007-2010) is now concluded. This report summarises th...

  2. Wind turbine blades: A study of prototypes in a steady regime - Unsteady considerations

    Science.gov (United States)

    Leblanc, R.; Goethals, R.; de Saint Louvent, B.

    1981-11-01

    The results of comparisons of numerical models with experimental results for the performance of prototype wind turbines in steady flows are presented, along with preliminary results on behavior in unsteady flows. The numerical models are based on previous schemes devised for propellers, with modifications for small perturbations, significant radial velocity effects from the wake, and the fact that the speed is induced. Two computational methods are currently used, one a method of short blades, the other the Prandtl lifting line theory. Trials have been run in the T4 wind tunnel using a 3 m horizontal axis machine and a 2.5 m Darrieus. Attention is given to modeling the structural dynamics and turbulent flow structures encountered by wind turbines. Experimental results relating windspeed, angle of attack, and output are presented. Optimization studies have indicated that wind farms will require a 6-7 blade diameter unit spacing to maintain satisfactory group output efficiencies.

  3. An experimental and numerical study of the atmospheric stability impact on wind turbine wakes

    DEFF Research Database (Denmark)

    Machefaux, Ewan; Larsen, Gunner Chr.; Koblitz, Tilman

    2016-01-01

    campus test site. Wake measurements are averaged within a mean wind speed bin of 1 m s1 and classified according to atmospheric stability using three different metrics: the Obukhov length, the Bulk–Richardson number and the Froude number. Three test cases are subsequently defined covering various...... atmospheric conditions. Simulations are carried out using large eddy simulation and actuator disk rotor modeling. The turbulence properties of the incoming wind are adapted to the thermal stratification using a newly developed spectral tensor model that includes buoyancy effects. Discrepancies are discussed......In this paper, the impact of atmospheric stability on a wind turbine wake is studied experimentally and numerically. The experimental approach is based on full-scale (nacelle based) pulsed lidar measurements of the wake flow field of a stall-regulated 500 kW turbine at the DTU Wind Energy, Risø...

  4. Momentum flux of the solar wind near planetary magnetospheres: a comparative study

    International Nuclear Information System (INIS)

    Perez de Tejada, H.

    1985-01-01

    A study of the velocity profiles of the shocked solar wind exterior to the magnetospheres of the Earth, Mars and Venus is presented. A characteristic difference exists between the conditions present in planets with and without a strong intrinsic magnetic field. In a strongly magnetized planet (as it is the case in the earth), the velocity of the solar wind near the magnetopause remains nearly constant along directions normal to that boundary. In weakly magnetized planets (Venus, Mars), on the other hand, the velocity profile near the magnetopause/ionopause exhibits a transverse gradient which implies decreased values of the momentum flux of the solar wind in those regions. The implications of the different behavior of the shocked solar wind are discussed in connection with the nature of the interaction process that takes place in each case. (author)

  5. Numerical study on aerodynamic damping of floating vertical axis wind turbines

    DEFF Research Database (Denmark)

    Cheng, Zhengshun; Aagaard Madsen, Helge; Gao, Zhen

    2016-01-01

    Harvesting offshore wind energy resources using floating vertical axis wind turbines (VAWTs) has attracted an increasing interest in recent years. Due to its potential impact on fatigue damage, the aerodynamic damping should be considered in the preliminary design of a floating VAWT based...... on the frequency domain method. However, currently the study on aerodynamic damping of floating VAWTs is very limited. Due to the essential difference in aerodynamic load characteristics, the aerodynamic damping of a floating VAWT could be different from that of a floating horizontal axis wind turbine (HAWT...... to four were considered. The aerodynamic damping under steady and turbulent wind conditions were estimated using fully coupled aero-hydro-servo-elastic time domain simulations. It is found that the aerodynamic damping ratio of the considered floating VAWTs ranges from 1.8% to 5.3%. Moreover...

  6. Beam tracking strategies for studies of kinetic scales in the solar wind with THOR-CSW

    Science.gov (United States)

    De Keyser, Johan; Lavraud, Benoit; Neefs, Eddy; Berkenbosch, Sophie; Anciaux, Michel; Maggiolo, Romain

    2016-04-01

    Modern plasma spectrometers for monitoring the solar wind attempt to intelligently track the energy and direction of the solar wind beam in order to obtain solar wind velocity distributions more efficiently. Such beam tracking strategies offer some benefits, but also have their limitations and drawbacks. Benefits include an improved resolution and/or a faster velocity distribution function acquisition time. Limitations are due to instrument characteristics that tend to be optimized for a particular range of particle energies and arrival directions. A drawback is the risk to miss an important part of the velocity distribution or to lose track of the beam altogether. A comparison is presented of different beam tracking strategies under consideration for the THOR-CSW instrument in order to highlight a number of design decisions and their impact on the acquired velocity distributions. The gain offered by beam tracking in terms of increased time resolution turns out to be essential for studies of solar wind physics at kinetic scales.

  7. Production of electricity from the wind: a preliminary feasibility study for Greece

    Energy Technology Data Exchange (ETDEWEB)

    Galanis, N

    1977-01-01

    Wind statistics for Greece show that the conditions prevailing on the Aegean islands--i.e. considerable amounts of wind energy, small electrical loads and high generation costs--are especially favorable for the installation of wind turbine generators (WTGs). This study gives preliminary design parameters for WTGs at six locations and evaluates their performance. The duration of operation varies from 5000 to 7400 hours annually and the specific production is between 2300 and 3600 kwh/kw. The installation of the WTGs would result in diesel fuel savings corresponding to a month's consumption. Finally, the cost of wind generated electricity will be lower than that from diesel engines one to three years after the installation of the WTGs.

  8. Studies for Characterisation of Electrical Properties of DC Collection System in Offshore Wind Farms

    DEFF Research Database (Denmark)

    Chen, Yu-Hsing; Dincan, Catalin Gabriel; Olsen, Rolant Joannesarson

    2016-01-01

    Offshore HVDC-connected wind farms where the wind plant power collection network becomes DC, rather than AC, offer reduced electrical losses, lower equipment ratings potentially leading to lower bill-of-material cost, and undiminished functionality. However, no standards exist for an offshore...... medium-voltage DC power collection cable-based system, routing power from MVDC wind turbines all the way to the HVDC export cable. To progress, it is therefore important to establish some common reference for the design and performance of the components needed in an MVDC collection network. Any suggested...... of the MVDC power collection, regardless of choice of turbine converter circuit, MVDC cable configuration, use of DC circuit breakers, substation converter circuit, control and protection. The paper presents the necessary list of studies, and includes examples of simulation results for an exemplary MVDC wind...

  9. Western Wind and Solar Integration Study Phase 3 – Frequency Response and Transient Stability

    Energy Technology Data Exchange (ETDEWEB)

    Miller, N. W. [GE Energy Management, Schenectady, NY (United States); Shao, M. [GE Energy Management, Schenectady, NY (United States); Pajic, S. [GE Energy Management, Schenectady, NY (United States); D' Aquila, R. [GE Energy Management, Schenectady, NY (United States)

    2014-12-01

    Power system operators and utilities worldwide have concerns about the impact of high-penetration wind and solar generation on electric grid reliability (EirGrid 2011b, Hydro-Quebec 2006, ERCOT 2010). The stability of North American grids under these conditions is a particular concern and possible impediment to reaching future renewable energy goals. Phase 3 of the Western Wind and Solar Integration Study (WWSIS-3) considers a 33% wind and solar annual energy penetration level that results in substantial changes to the characteristics of the bulk power system, including different power flow patterns, different commitment and dispatch of existing synchronous generation, and different dynamic behavior of wind and solar generation. WWSIS-3 evaluates two specific aspects of fundamental frequency system stability: frequency response and transient stability.

  10. CFD and Experimental Studies on Wind Turbines in Complex Terrain by Improved Actuator Disk Method

    Science.gov (United States)

    Liu, Xin; Yan, Shu; Mu, Yanfei; Chen, Xinming; Shi, Shaoping

    2017-05-01

    In this paper, an onshore wind farm in mountainous area of southwest China was investigated through numerical and experimental methods. An improved actuator disk method, taking rotor data (i.e. blade geometry information, attack angle, blade pitch angle) into account, was carried out to investigate the flow characteristic of the wind farm, especially the wake developing behind the wind turbines. Comparing to the classic AD method and the situ measurements, the improved AD shows better agreements with the measurements. The turbine power was automatically predicted in CFD by blade element method, which agreed well with the measurement results. The study proved that the steady CFD simulation with improved actuator disk method was able to evaluate wind resource well and give good balance between computing efficiency and accuracy, in contrary to much more expensive computation methods such as actuator-line/actuator-surface transient model, or less accurate methods such as linear velocity reduction wake model.

  11. On sensitivity value of pair-matched observational studies

    OpenAIRE

    Zhao, Qingyuan

    2017-01-01

    An observational study may be biased for estimating causal effects by failing to control for unmeasured confounders. This paper proposes a new quantity called the "sensitivity value", which is defined as the minimum strength of unmeasured confounders needed to change the qualitative conclusions of a naive analysis assuming no unmeasured confounder. We establish the asymptotic normality of the sensitivity value in pair-matched observational studies. The theoretical results are then used to app...

  12. Clinical study of the hypothesis of endogenous collateral wind on acute coronary syndrome: a review.

    Science.gov (United States)

    Wang, Xian; Zhang, Cong; Yang, Ran; Zhu, Haiyan; Zhao, Huaibing; Li, Xiaoming

    2014-01-01

    Acute Coronary Syndrome (ACS), is a serious threat to people's health, and life, and in recent years, the incidence has increased yearly. This study was to propose the hypothesis of "endogenous collateral wind" based on the patho-mechanism of thrombogenesis complicated by ruptured plaque on ACS, and the theory of traditional Chinese medicine. Through successful coronary angiography (CAG), and intravascular ultrasound (IVUS), patients with coronary artery disease were made the differential diagnosis such as blood stasis, blood stasis due to phlegm obstruction, and endogenous collateral wind. The levels of plasma inflammatory marker were measured to study on the characteristics of "endogenous collateral wind". Luo heng dripping pills with promoting blood circulation to expel wind-evil, and remove wetness were made based on the hypothesis of "endogenous collateral wind" on ACS. Patients with unstable angina were randomly divided into 3, groups based on therapeutic methods: conventional therapy group, Luo Heng dripping pills group and Tongxinluo caps. Differences among groups were compared. There were great changes in number and degree of coronary arteriostenosis confirmed by CAG, the types of ACC/AHA lesion and Levin lesion confirmed by CAG, remodeling index, positive or negative remodeling percentage measured by IVUS, the plasma levels of plasma inflammatory marker measured by ELLSA in the patients with endogenous collateral wind, compared with patients with blood stasis and blood stasis due to phlegm obstruction. The total effective rate of improved angina in Luo Heng dripping pills group was significantly higher than those in other two groups. The levels of plasma inflammatory marker were significantly lower in Luo Heng dripping pills group. There were some pathological basis which were found about the hypothesis of "endogenous collateral wind" on acute coronary syndrome. It provided evidences for patients with coronary artery disease treated by medicines with

  13. Statistical study of chorus wave distributions in the inner magnetosphere using Ae and solar wind parameters

    Science.gov (United States)

    Aryan, Homayon; Yearby, Keith; Balikhin, Michael; Agapitov, Oleksiy; Krasnoselskikh, Vladimir; Boynton, Richard

    2014-08-01

    Energetic electrons within the Earth's radiation belts represent a serious hazard to geostationary satellites. The interactions of electrons with chorus waves play an important role in both the acceleration and loss of radiation belt electrons. The common approach is to present model wave distributions in the inner magnetosphere under different values of geomagnetic activity as expressed by the geomagnetic indices. However, it has been shown that only around 50% of geomagnetic storms increase flux of relativistic electrons at geostationary orbit while 20% causes a decrease and the remaining 30% has relatively no effect. This emphasizes the importance of including solar wind parameters such as bulk velocity (V), density (n), flow pressure (P), and the vertical interplanetary magnetic field component (Bz) that are known to be predominately effective in the control of high energy fluxes at the geostationary orbit. Therefore, in the present study the set of parameters of the wave distributions is expanded to include the solar wind parameters in addition to the geomagnetic activity. The present study examines almost 4 years (1 January 2004 to 29 September 2007) of Spatio-Temporal Analysis of Field Fluctuation data from Double Star TC1 combined with geomagnetic indices and solar wind parameters from OMNI database in order to present a comprehensive model of wave magnetic field intensities for the chorus waves as a function of magnetic local time, L shell (L), magnetic latitude (λm), geomagnetic activity, and solar wind parameters. Generally, the results indicate that the intensity of chorus emission is not only dependent upon geomagnetic activity but also dependent on solar wind parameters with velocity and southward interplanetary magnetic field Bs (Bz < 0), evidently the most influential solar wind parameters. The largest peak chorus intensities in the order of 50 pT are observed during active conditions, high solar wind velocities, low solar wind densities, high

  14. Using data-driven approach for wind power prediction: A comparative study

    International Nuclear Information System (INIS)

    Taslimi Renani, Ehsan; Elias, Mohamad Fathi Mohamad; Rahim, Nasrudin Abd.

    2016-01-01

    Highlights: • Double exponential smoothing is the most accurate model in wind speed prediction. • A two-stage feature selection method is proposed to select most important inputs. • Direct prediction illustrates better accuracy than indirect prediction. • Adaptive neuro fuzzy inference system outperforms data mining algorithms. • Random forest performs the worst compared to other data mining algorithm. - Abstract: Although wind energy is intermittent and stochastic in nature, it is increasingly important in the power generation due to its sustainability and pollution-free. Increased utilization of wind energy sources calls for more robust and efficient prediction models to mitigate uncertainties associated with wind power. This research compares two different approaches in wind power forecasting which are indirect and direct prediction methods. In indirect method, several times series are applied to forecast the wind speed, whereas the logistic function with five parameters is then used to forecast the wind power. In this study, backtracking search algorithm with novel crossover and mutation operators is employed to find the best parameters of five-parameter logistic function. A new feature selection technique, combining the mutual information and neural network is proposed in this paper to extract the most informative features with a maximum relevancy and minimum redundancy. From the comparative study, the results demonstrate that, in the direct prediction approach where the historical weather data are used to predict the wind power generation directly, adaptive neuro fuzzy inference system outperforms five data mining algorithms namely, random forest, M5Rules, k-nearest neighbor, support vector machine and multilayer perceptron. Moreover, it is also found that the mean absolute percentage error of the direct prediction method using adaptive neuro fuzzy inference system is 1.47% which is approximately less than half of the error obtained with the

  15. Environmental studies related to the operation of wind energy conversion systems. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Rogers, S.E.; Cornaby, B.W.; Rodman, C.W.; Sticksel, P.R.; Tolle, D.A.

    1977-12-01

    This biophysical impact assessment explores the environmental consequences of the emerging wind energy conversion technology through field studies done at the DOE/NASA 100-kW Experimental Wind Turbine located at NASA Lewis Research Center's Plum Brook Station near Sandusky, Ohio. A micrometeorological field program monitored changes in the downwind wake of the wind turbine. Horizontal and/or vertical measurements of wind speed, temperature, carbon dioxide concentration, precipitation, and incident solar radiation showed measurable variation within the wake only for precipitation and wind speed. The changes were minor and not likely to result in any secondary effects to vegetation, including crops, because they are within the natural range of variability in the site environment. Effects are negligible beyond the physically altered area of the tower pad, access, and control structures. The wind turbine has not proved to be a high risk to airborne fauna, including the most vulnerable night-migrating songbirds. Behavioral studies indicate the birds will avoid the turbine if they can see it.

  16. Contribution to the study of the wind and solar radiation over Guadeloupe

    International Nuclear Information System (INIS)

    Bertin, A.; Frangi, J.P.

    2013-01-01

    Highlights: • We study wind and solar resource in Guadeloupe (FWI). • Weibull distributions reveal a nocturnal radiative layer blocking wind at airport. • We provide monthly and annual irradiations, horizontal and tilted, for four sites. • Five Linke turbidity coefficient calculation methods are reviewed and compared. - Abstract: Guadeloupean archipelago must reach energy autonomy in 2030 and include at least 50% of renewables in 2020, where wind and photovoltaics can play a significant role. Still, Guadeloupe gathers a lot of landscapes having great impact on wind and solar resource. Study of three 10-years database and one 5-year database locates a nocturnal radiative layer above the airport meteorological station, drastically limiting the wind potential there, and gives all the irradiation components (monthly sums) and therefore key parameters for photovoltaic energy yield. This paper also points out the underestimation of Linke turbidity coefficient in the airport station with Solar Radiation Database (SoDa), compared to ground-based determination, and calculates the value of this coefficient for three stations across Guadeloupe. All those parameters are discussed, as being of importance to make fair predictions of statistical relationships involving preliminary assessment and modeling of wind and solar energy systems. These results can then be used in neighboring countries, Guadeloupe having various meteorological conditions retrieved in Caribbean

  17. Hybrid Model of Inhomogeneous Solar Wind Plasma Heating by Alfven Wave Spectrum: Parametric Studies

    Science.gov (United States)

    Ofman, L.

    2010-01-01

    Observations of the solar wind plasma at 0.3 AU and beyond show that a turbulent spectrum of magnetic fluctuations is present. Remote sensing observations of the corona indicate that heavy ions are hotter than protons and their temperature is anisotropic (T(sub perpindicular / T(sub parallel) >> 1). We study the heating and the acceleration of multi-ion plasma in the solar wind by a turbulent spectrum of Alfvenic fluctuations using a 2-D hybrid numerical model. In the hybrid model the protons and heavy ions are treated kinetically as particles, while the electrons are included as neutralizing background fluid. This is the first two-dimensional hybrid parametric study of the solar wind plasma that includes an input turbulent wave spectrum guided by observation with inhomogeneous background density. We also investigate the effects of He++ ion beams in the inhomogeneous background plasma density on the heating of the solar wind plasma. The 2-D hybrid model treats parallel and oblique waves, together with cross-field inhomogeneity, self-consistently. We investigate the parametric dependence of the perpendicular heating, and the temperature anisotropy in the H+-He++ solar wind plasma. It was found that the scaling of the magnetic fluctuations power spectrum steepens in the higher-density regions, and the heating is channeled to these regions from the surrounding lower-density plasma due to wave refraction. The model parameters are applicable to the expected solar wind conditions at about 10 solar radii.

  18. Simulation and study of power quality issues in a fixed speed wind farm substation.

    Science.gov (United States)

    Magesh, T; Chellamuthu, C

    2015-01-01

    Power quality issues associated with the fixed speed wind farm substation located at Coimbatore district are investigated as the wind generators are tripping frequently. The investigations are carried out using two power quality analyzers, Fluke 435 and Dranetz PX5.8, with one of them connected at group control breaker of the 110 kV feeder and the other at the selected 0.69 kV generator busbar during the period of maximum power generation. From the analysis of the recorded data it is found that sag, swell, and transients are the major events which are responsible for the tripping of the generators. In the present study, simulation models for wind, turbine, shaft, pitch mechanism, induction generator, and grid are developed using DIgSILENT. Using the turbine characteristics, a two-dimensional lookup table is designed to generate a reference pitch angle necessary to simulate the power curve of the passive stall controlled wind turbine. Various scenarios and their effects on the performance of the wind farm are studied and validated with the recorded data and waveforms. The simulation model will be useful for the designers for planning and development of the wind farm before implementation.

  19. Simulation and Study of Power Quality Issues in a Fixed Speed Wind Farm Substation

    Directory of Open Access Journals (Sweden)

    T. Magesh

    2015-01-01

    Full Text Available Power quality issues associated with the fixed speed wind farm substation located at Coimbatore district are investigated as the wind generators are tripping frequently. The investigations are carried out using two power quality analyzers, Fluke 435 and Dranetz PX5.8, with one of them connected at group control breaker of the 110 kV feeder and the other at the selected 0.69 kV generator busbar during the period of maximum power generation. From the analysis of the recorded data it is found that sag, swell, and transients are the major events which are responsible for the tripping of the generators. In the present study, simulation models for wind, turbine, shaft, pitch mechanism, induction generator, and grid are developed using DIgSILENT. Using the turbine characteristics, a two-dimensional lookup table is designed to generate a reference pitch angle necessary to simulate the power curve of the passive stall controlled wind turbine. Various scenarios and their effects on the performance of the wind farm are studied and validated with the recorded data and waveforms. The simulation model will be useful for the designers for planning and development of the wind farm before implementation.

  20. Raptor interactions with wind energy: Case studies from around the world

    Science.gov (United States)

    Watson, Richard T.; Kolar, Patrick S.; Ferrer, Miguel; Nygård, Torgeir; Johnston, Naira; Hunt, W. Grainger; Smit-Robinson, Hanneline A.; Farmer, Christopher J; Huso, Manuela; Katzner, Todd

    2018-01-01

    The global potential for wind power generation is vast, and the number of installations is increasing rapidly. We review case studies from around the world of the effects on raptors of wind-energy development. Collision mortality, displacement, and habitat loss have the potential to cause population-level effects, especially for species that are rare or endangered. The impact on raptors has much to do with their behavior, so careful siting of wind-energy developments to avoid areas suited to raptor breeding, foraging, or migration would reduce these effects. At established wind farms that already conflict with raptors, reduction of fatalities may be feasible by curtailment of turbines as raptors approach, and offset through mitigation of other human causes of mortality such as electrocution and poisoning, provided the relative effects can be quantified. Measurement of raptor mortality at wind farms is the subject of intense effort and study, especially where mitigation is required by law, with novel statistical approaches recently made available to improve the notoriously difficult-to-estimate mortality rates of rare and hard-to-detect species. Global standards for wind farm placement, monitoring, and effects mitigation would be a valuable contribution to raptor conservation worldwide.

  1. Finite element structural study of the VGOT wind turbine

    Energy Technology Data Exchange (ETDEWEB)

    Otero, A.D. [University of Buenos Aires (Argentina). College of Engineering; Ponta, F.L. [University of Illinois, Urbana, IL (United States). Dept. of Theoretical and Applied Mechanics

    2004-07-01

    We analyse the implementation of the finite element method to simulate the structural behaviour of the blade-wagons of variable-geometry oval-trajectory (VGOT) Darrieus wind turbines. The key feature of a VGOT machine is that each blade, instead of rotating around a central vertical axis, slides over rails mounted on a wagon formed by a tubular reticulated structure supported by standard train bogies. The structure should be designed to absorb the efforts in the vertical and traverse directions of the railroad due to the aerodynamic loads, the weight of the components and the centrifugal acceleration along the curved tracks. We show some results for the tip deflection and the tip torsion of the blade, the frontal and lateral angle variations in the blade bottom and the Von Misses tensions of five sample beams, all of them in function of the trajectory-length parameter; and some examples of the deformed configuration of the reticulated structure. (author)

  2. Potential risks at an industrial site: A wind tunnel study

    Czech Academy of Sciences Publication Activity Database

    Jaňour, Zbyněk; Jurčáková, Klára; Brych, Karel; Dittrt, František; Dittrich, F.

    2010-01-01

    Roč. 88, č. 3 (2010), s. 185-190 ISSN 0957-5820 R&D Projects: GA MŠk(CZ) OC 113 Institutional research plan: CEZ:AV0Z20760514; CEZ:AV0Z20600510 Keywords : atmospheric turbulence * flow visualization * wind tunnel modeling Subject RIV: DG - Athmosphere Sciences, Meteorology Impact factor: 1.453, year: 2010 http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B8JGG-4Y7P8YF-1&_user=640952&_coverDate=05%2F31%2F2010&_rdoc=1&_fmt=high&_orig=search&_sort=d&_docanchor=&view=c&_searchStrId=1433050901&_rerunOrigin= google &_acct=C000034318&_version=1&_urlVersion=0&_userid=640952&md5=b036d2c5d747eadc03ff5697ea45e6a2

  3. Expert judgment study on wind pressure coefficients. Part 2 : Unprocessed data: Expert rationales Wind tunnel data. Final report

    NARCIS (Netherlands)

    De Wit, S.

    1999-01-01

    In the design of low-rise buildings, wind tunnel experiments are scarcely employed to assess the wind-induced pressures, which are required e.g. for the simulation of ventilation flows or for the evaluation of the structural integrity. Instead, techniques are used, which predominandy rely on inter-

  4. Comparison of two LES codes for wind turbine wake studies

    International Nuclear Information System (INIS)

    Sarlak, H; Mikkelsen, R; Sørensen, J N; Pierella, F

    2014-01-01

    For the third time a blind test comparison in Norway 2013, was conducted comparing numerical simulations for the rotor C p and C t and wake profiles with the experimental results. As the only large eddy simulation study among participants, results of the Technical University of Denmark (DTU) using their in-house CFD solver, EllipSys3D, proved to be more reliable among the other models for capturing the wake profiles and the turbulence intensities downstream the turbine. It was therefore remarked in the workshop to investigate other LES codes to compare their performance with EllipSys3D. The aim of this paper is to investigate on two CFD solvers, the DTU's in-house code, EllipSys3D and the open-sourse toolbox, OpenFoam, for a set of actuator line based LES computations. Two types of simulations are performed: the wake behind a signle rotor and the wake behind a cluster of three inline rotors. Results are compared in terms of velocity deficit, turbulence kinetic energy and eddy viscosity. It is seen that both codes predict similar near-wake flow structures with the exception of OpenFoam's simulations without the subgrid-scale model. The differences begin to increase with increasing the distance from the upstream rotor. From the single rotor simulations, EllipSys3D is found to predict a slower wake recovery in the case of uniform laminar flow. From the 3-rotor computations, it is seen that the difference between the codes is smaller as the disturbance created by the downstream rotors causes break down of the wake structures and more homogenuous flow structures. It is finally observed that OpenFoam computations are more sensitive to the SGS models

  5. A Standardized Based Approach to Managing Atmosphere Studies For Wind Energy Research

    Science.gov (United States)

    Stephan, E.; Sivaraman, C.

    2015-12-01

    Atmosphere to Electrons (A2e) is a multi-year U.S. Department of Energy (DOE) research initiative targeting significant reductions in the cost of wind energy through an improved understanding of the complex physics governing wind flow into and through wind farms. Better insight into the flow physics has the potential to reduce wind farm energy losses by up to 20%, to reduce annual operational costs by hundreds of millions of dollars, and to improve project financing terms to more closely resemble traditional capital projects. The Data Archive and Portal (DAP) is a key capability of the A2e initiative. The DAP is a cloud-based distributed system known as the 'Wind Cloud' that functions as a repository for all A2e data. This data includes numerous historic and on-going field studies involving in situ and remote sensing instruments, simulations, and scientific analysis. Significantly it is the integration and sharing of these diverse data sets through the DAP that is key to meeting the goals of A2e. This cloud will be accessible via an open and easy-to navigate user interface that facilitates community data access, interaction, and collaboration. DAP management is working with the community, industry, and international standards bodies to develop standards for wind data and to capture important characteristics of all data in the Wind Cloud. Security will be provided to facilitate storage of proprietary data alongside publicly accessible data in the Wind Cloud, and the capability to generate anonymized data will be provided to facilitate using private data by non-privileged users (when appropriate). Finally, limited computing capabilities will be provided to facilitate co-located data analysis, validation, and generation of derived products in support of A2e science.

  6. A preliminary study of thermosphere and mesosphere wind observed by Fabry-Perot over Kelan, China

    Science.gov (United States)

    Yu, Tao; Huang, Cong; Zhao, Guangxin; Mao, Tian; Wang, Yungang; Zeng, Zhongcao; Wang, Jingsong; Xia, Chunliang

    2014-06-01

    A Fabry-Perot interferometer (FPI) system was deployed in Kelan (38.7°N, 111.6°E), center China in November 2011, which observes the airglows at wavelengths of 892.0 nm, 557.7 nm, and 630.0 nm from OH and OI emissions in the upper atmosphere, to derive the wind and temperature at heights around 87 km, 97 km, and 250 km, respectively. From late 2011 through 2013 a series of more than 4500 measurements at each height are validated according to manufacture data quality criteria. By using these data, the morphology of wind in the mesosphere and thermosphere is investigated in this study. Preliminary results are as follows: (1) As for the diurnal variation, meridional and zonal winds at heights of 87 km and 97 km, which are derived through 892.0 nm and 557.7 nm airglows, usually range from -50 m/s to 30 m/s and -50 m/s to 50 m/s, respectively, with typical random errors of about 6-10 m/s at 87 km and 2-3 m/s at 97 km. Meridional winds usually are northward at dusk, southward at middle night, and back to northward at dawn; and zonal winds usually are eastward at dusk, westward at middle night, and back to eastward at dawn. The monthly mean winds are in good agreement with those of HWM93 results. Meridional and zonal winds at a height of 250 km, which are derived through 630.0 nm nightglow, range from -110 m/s to 80 m/s with typical random errors of about 8-10 m/s. Meridional winds usually are northward at dusk, southward at middle night, and back to northward at dawn; and zonal winds usually are eastward at dusk, zero at middle night, and westward at dawn; and they are also well consistent with HWM93 results. (2) As for the seasonal variation, meridional winds at the heights of 87 km and 97 km have a visible annual variation at 12-17 LT and with a little semiannual variation at all other hours, but the zonal winds at the heights of 87 km and 97 km have a semiannual variation all night. The seasonal dependence of the winds, both meridional and zonal winds, at the height

  7. Current scenario of the wind energy in Pakistan challenges and future perspectives: A case study

    Directory of Open Access Journals (Sweden)

    Mazhar H. Baloch

    2016-11-01

    Full Text Available Electricity plays an important role in the socioeconomic growth and social prosperity of any country. It is to be considered as the basic need for human development. Nowadays, low production of electricity is a serious problem in Pakistan, which directly restricts the development of the state. One-third of Pakistan’s population does not have any electricity in the rural areas and about 10–12 hours load shedding in urban areas and is quite common. Although, the state of Pakistan always shows a deficit in the conventional resources, but no progress was also being made in the renewable resources such as the wind and solar energy. Therefore, it is better to utilize these natural assets in order to fulfill the electricity supply the country. In this manuscript, our main objective is to study and outlooks the country energy profile situation vis-à-vis wind energy potential characteristics of the most important wind corridor in the southern part of the country. Pakistan has around 1100 kilometers (km coastal line for the wind energy potential, but in this manuscript, we have chosen one of the most suitable wind corridors of the southern part of the country. We also tried to prove theoretically that this wind zone is more favorable for country consumer demand. Moreover, future perspective and the major challenges during windmill implementation is also being discussed herein.

  8. Experimental study of separator effect and shift angle on crossflow wind turbine performance

    Science.gov (United States)

    Fahrudin, Tjahjana, Dominicus Danardono Dwi Prija; Santoso, Budi

    2018-02-01

    This paper present experimental test results of separator and shift angle influence on Crossflow vertical axis wind turbine. Modification by using a separator and shift angle is expected to improve the thrust on the blade so as to improve the efficiency. The design of the wind turbine is tested at different wind speeds. There are 2 variations of crossflow turbine design which will be analyzed using an experimental test scheme that is, 3 stage crossflow and 2 stage crossflow with the shift angle. Maximum power coefficient obtained as Cpmax = 0.13 at wind speed 4.05 m/s for 1 separator and Cpmax = 0.12 for 12° shear angle of wind speed 4.05 m/s. In this study, power characteristics of the crossflow rotor with separator and shift angle have been tested. The experimental data was collected by variation of 2 separator and shift angle 0°, 6°, 12° and wind speed 3.01 - 4.85 m/s.

  9. Large-scale introduction of wind power stations in the Swedish grid: a simulation study

    Energy Technology Data Exchange (ETDEWEB)

    Larsson, L

    1978-08-01

    This report describes a simulation study on the factors to be considered if wind power were to be introduced to the south Swedish power grid on a large scale. The simulations are based upon a heuristic power generation planning model, developed for the purpose. The heuristic technique reflects the actual running strategies of a big power company with suitable accuracy. All simulations refer to certain typical days in 1976 to which all wind data and system characteristics are related. The installed amount of wind power will not be subject to optimization. All differences between planned and real wind power generation is equalized by regulation of the hydro power. The simulations made differ according to how the installed amount of wind power is handled in the power generation planning. The simulations indicate that the power system examined could well bear an introduction of wind power up to a level of 20% of the total power installed. This result is of course valid only for the days examined and does not necessarily apply to the present day structure of the system.

  10. Experimental Study of a Small Scale Hydraulic System for Mechanical Wind Energy Conversion into Heat

    Directory of Open Access Journals (Sweden)

    Tadas Zdankus

    2016-07-01

    Full Text Available Significant potential for reducing thermal energy consumption in buildings of moderate and cold climate countries lies within wind energy utilisation. Unlike solar irradiation, character of wind speeds in Central and Northern Europe correspond to the actual thermal energy demand in buildings. However, mechanical wind energy undergoes transformation into electrical energy before being actually used as thermal energy in most wind energy applications. The study presented in this paper deals with hydraulic systems, designed for small-scale applications to eliminate the intermediate energy transformation as it converts mechanical wind energy into heat directly. The prototype unit containing a pump, flow control valve, oil tank and piping was developed and tested under laboratory conditions. Results of the experiments showed that the prototype system is highly efficient and adjustable to a broad wind velocity range by modifying the definite hydraulic system resistance. Development of such small-scale replicable units has the potential to promote “bottom-up” solutions for the transition to a zero carbon society.

  11. WindPACT Turbine Design Scaling Studies Technical Area 2: Turbine, Rotor and Blade Logistics; TOPICAL

    International Nuclear Information System (INIS)

    Smith, K.

    2001-01-01

    Through the National Renewable Energy Laboratory (NREL), the United States Department of Energy (DOE) implemented the Wind Partnership for Advanced Component Technologies (WindPACT) program. This program will explore advanced technologies that may reduce the cost of energy (COE) from wind turbines. The initial step in the WindPACT program is a series of preliminary scaling studies intended to determine the optimum sizes for future turbines, help define sizing limits for certain critical technologies, and explore the potential for advanced technologies to contribute to reduced COE as turbine scales increase. This report documents the results of Technical Area 2-Turbine Rotor and Blade Logistics. For this report, we investigated the transportation, assembly, and crane logistics and costs associated with installation of a range of multi-megawatt-scale wind turbines. We focused on using currently available equipment, assembly techniques, and transportation system capabilities and limitations to hypothetically transport and install 50 wind turbines at a facility in south-central South Dakota

  12. Experimental study of wind tunnel performance by a two-component laserDopplerAnemometer

    Directory of Open Access Journals (Sweden)

    M Pourmahabadian

    2005-10-01

    Full Text Available Background and Aims: This survey studies the wind tunnel performance by a two- componentlaser Doppler Anemometer, so some experiments were carried out to assess the performance of awind tunnel.Method: The tunnel was capable to produce air velocity of up to 40 m/s.. Measurements ofvelocity profiles have been made actors the test section of wind tunnel through the using a twocomponentfiber optic Laser Doppler anemometer. Measurements of velocity profiles andturbulence intensities have been made across the test section of the wind tunnel using a twocomponentfiber optic Laser Doppler anemometer (I.D.A for wind speeds ranging from 1 to3m/s.Results: Performance rests of velocity profiles at a given flow rate and various position of aerosolgenerator showed that although uniformity of flow dependent to the place of an atomizer (asaerosol generator but the variation of wind speed across the test section meets the wind speedrequirements, as specified by US EPAfor 3m/s only.Conclusion:At time which particles velocity reach to less than one micron, the air velocity relateson the similarity of particles and

  13. Modelling Wind for Wind Farm Layout Optimization Using Joint Distribution of Wind Speed and Wind Direction

    OpenAIRE

    Ju Feng; Wen Zhong Shen

    2015-01-01

    Reliable wind modelling is of crucial importance for wind farm development. The common practice of using sector-wise Weibull distributions has been found inappropriate for wind farm layout optimization. In this study, we propose a simple and easily implementable method to construct joint distributions of wind speed and wind direction, which is based on the parameters of sector-wise Weibull distributions and interpolations between direction sectors. It is applied to the wind measurement data a...

  14. Health impact of wind farms.

    Science.gov (United States)

    Kurpas, Donata; Mroczek, Bozena; Karakiewicz, Beata; Kassolik, Krzysztof; Andrzejewski, Waldemar

    2013-01-01

    Wind power is employed worldwide as an alternative source of energy. At the same time, however, the health effects of wind turbines have become a matter of discussion. The purpose of this study is a critical review of available reports providing arguments both for and against the construction of wind farms. The authors also attempt to propose recommendations in accordance with the Evidence-Based Medicine (EBM) guidelines. In the case of exposure to wind farms, a randomized controlled trial (RCT) is impossible. To obtain the highest-level recommendations, analysis of case-control studies or cohort studies with control groups should be performed. Preferably, it should include geostatistical analysis conducted with the use of variograms and the kriging technique. Combinations of key words were entered into the Thomson Reuters Web of Knowledge (SM) and the Internet search engine Google. SHORT DESCRIPTION OF STATE OF THE ART: The nuisance caused by wind turbines is stereotypically linked with the noise that they produce. Nevertheless, the visual aspect of wind farms, opinions about them, and sensitivity to sound seem to be of the greater importance. To date, the direct correlations between the vicinity of modern wind farms, the noise that wind turbines make, and possible consequences to health have not been described in peer reviewed articles. Health effects are more probably associated with some environmental factors leading to annoyance or frustration. All types of studies share the same conclusion: wind turbines can provoke annoyance. As with any project involving changes in the local environment, a certain level of irritation among the population can be expected. There are elected officials and government representatives who should decide what level of social annoyance is acceptable, and whether wind power advantages outweigh its potential drawbacks. The influence of wind turbines on human emotional and physical health is a relatively new field of research. Further

  15. Understanding the environmental implications of energy transitions. A case study for wind power

    Energy Technology Data Exchange (ETDEWEB)

    Arvesen, Anders

    2013-03-01

    of recycling benefits in analyses, lack of detailed considerations of installation and use phases, and lack of future-oriented assessments. The scenario-based LCA is an initial attempt to integrate global energy scenario analysis and LCA in order to assess the economy-wide environmental costs and benefits of wind power. The study estimates aggregated global emissions caused by wind power toward 2050, following the International Energy Agency#Right Single Quotation Mark#s BLUE scenarios. It takes into account replacement at end-of-life and changing electricity mix in manufacturing, and distinguishes emissions occurring prior to, during and after the useful life of wind turbines. Results indicate emissions of 2.3 (3.5) gigatonnes Co2 from wind power in 2007-50 in a scenario with 12% (22%) share of wind in electricity supply in 2050. A second key element of the analysis is that life cycle inventories for fossil fuel-based electricity are used to evaluate emissions savings from wind power; the evaluation is performed on the assumption that additional wind electricity, compared with a baseline, displaces fossil fuel electricity. Results suggest that emissions savings grossly exceed emissions caused by wind power, and thus confirm emission benefits of wind power. Uncertainty and limitations in scope of analysis need to be borne in mind when interpreting results. The LCA of an offshore wind farm places special emphasis on marine vessel activities and supply of spare parts. The proposed Havsul I wind farm, Norway is used as a model. Total carbon footprint is estimated to 34 grams Co2 per kWh. Results indicate greater contributions from vessels and spare parts than has previously been thought: Offshore activities during installation and use phases contribute 25-35% to totals for several impact categories (e.g., climate change, acidification) and 43% for photochemical oxidant formation. Supply of spare parts causes 7% of climate impacts and 13% of freshwater ecotoxicity

  16. Techno economic analysis of a wind-photovoltaic-biomass hybrid renewable energy system for rural electrification: A case study of Kallar Kahar

    DEFF Research Database (Denmark)

    Ahmad, Jameel; Imran, Muhammad; Khalid, Abdullah

    2018-01-01

    . The comprehensive resource assessment of wind, biomass and solar energy is carried out for grid integration. Homer Pro software is used to model a hybrid microgrid system. Optimization results and sensitivity analysis is carried out to ensure the robustness and cost-effectiveness of the proposed hybrid microgrid......This paper focuses on the techno-economic feasibility of a grid-tied hybrid microgrid system for local inhabitants of Kallar Kahar near Chakwal city of Punjab province in Pakistan and investigates the potential for electricity generation through hybrid wind, photovoltaic and biomass system...... system. The total load has been optimally shared among generated power through wind, photovoltaic and biomass resources and surplus power is supplied to the national grid in case of low local demand of the load. The results of techno-economic feasibility study show that hybrid power system can generate...

  17. Factors of Renewable Energy Deployment and Empirical Studies of United States Wind Energy

    Science.gov (United States)

    Can Sener, Serife Elif

    Considered essential for countries' development, energy demand is growing worldwide. Unlike conventional sources, the use of renewable energy sources has multiple benefits, including increased energy security, sustainable economic growth, and pollution reduction, in particular greenhouse gas emissions. Nevertheless, there is a considerable difference in the share of renewable energy sources in national energy portfolios. This dissertation contains a series of studies to provide an outlook on the existing renewable energy deployment literature and empirically identify the factors of wind energy generation capacity and wind energy policy diffusion in the U.S. The dissertation begins with a systematic literature review to identify drivers and barriers which could help in understanding the diverging paths of renewable energy deployment for countries. In the analysis, economic, environmental, and social factors are found to be drivers, whereas political, regulatory, technical potential and technological factors are not classified as either a driver or a barrier (i.e., undetermined). Each main category contains several subcategories, among which only national income is found to have a positive impact, whereas all other subcategories are considered undetermined. No significant barriers to the deployment of renewable energy sources are found over the analyzed period. Wind energy deployment within the states related to environmental and economic factors was seldom discussed in the literature. The second study of the dissertation is thus focused on the wind energy deployment in the United States. Wind energy is among the most promising clean energy sources and the United States has led the world in per capita newly installed generation capacity since 2000. In the second study, using a fixed-effects panel data regression analysis, the significance of a number of economic and environmental factors are investigated for 39 states from 2000 to 2015. The results suggested that the

  18. Westerly Wind Bursts: a Synoptic-Dynamic Study

    Science.gov (United States)

    Hartten, Leslie Marie

    This research examines the synoptic and climatological settings of westerly wind bursts (WWBs) during the 1980s and the dynamical processes active during them. Probabilities of strong westerly and easterly 1000 mb winds over the western equatorial Pacific are presented. Westerlies exhibit a clear annual cycle, appearing in the north in July, moving southeastward as the year progresses, and disappearing by June. Conditional probabilities, dependent on the value of the SOI, show that strong westerlies are more likely and more geographically extensive when the SOI is low, especially from July through January. A newly developed two-dimensional classification scheme qualitatively describes the near-surface synoptic flow of almost 90% of the 131 WWBs identified during the decade. Only 8% of the WWBs are described by the pattern involving twin cyclonic circulations straddling the equator. The trades, tropical cyclones, and the southeast Asian monsoon are all at times linked to WWBs, and the synoptic patterns often contain a significant barotropic component. Breaks in WWB activity are well correlated with a cooler than normal western Pacific warm pool. However, near-equatorial WWBs do not show a good correlation with the Madden-Julian Oscillation. Four near-equatorial WWBs are examined in detail. All are associated with broad cross-equatorial flow; two also have a cyclonic circulation poleward of the westerlies. Anticyclonic relative vorticity equatorward of the burst displaces the zero line of absolute vorticity, eta, into the burst hemisphere. In the three Southern Hemisphere cases, horizontal advection in a region extending from north of New Guinea east-southeast toward the dateline is crucial to the generation and maintenance of the eta pattern. Vorticity stretching associated with convection helps maintain a tight gradient of eta near and poleward of the burst, but also drives the eta = 0 line back towards the equator as the burst ends. In the Northern Hemisphere case

  19. Feasibility study of a hybrid wind turbine system – Integration with compressed air energy storage

    International Nuclear Information System (INIS)

    Sun, Hao; Luo, Xing; Wang, Jihong

    2015-01-01

    Highlights: • A new hybrid wind turbine system is proposed and feasibility study if conducted. • A complete mathematical model is developed and implemented in a software environment. • Multi-mode control strategy is investigated to ensure the system work smoothly and efficiently. • A prototype for implementing the proposed mechanism is built and tested as proof of the concept. • The proposed system is proved to be technically feasible with energy efficiency around 50%. - Abstract: Wind has been recognized as one of major realistic clean energy sources for power generation to meet the continuously increased energy demand and to achieve the carbon emission reduction targets. However, the utilisation of wind energy encounters an inevitable challenge resulting from the nature of wind intermittency. To address this, the paper presents the recent research work at Warwick on the feasibility study of a new hybrid system by integrating a wind turbine with compressed air energy storage. A mechanical transmission mechanism is designed and implemented for power integration within the hybrid system. A scroll expander is adopted to serve as an “air-machinery energy converter”, which can transmit additional driving power generalized from the stored compressed air to the turbine shaft for smoothing the wind power fluctuation. A mathematical model for the complete hybrid process is developed and the control strategy is investigated for corresponding cooperative operations. A prototype test rig for implementing the proposed mechanism is built for proof of the concept. From the simulated and experimental studies, the energy conversion efficiency analysis is conducted while the system experiences different operation conditions and modes. It is proved that the proposed hybrid wind turbine system is feasible technically

  20. Comparative study of chaotic features in hourly wind speed using recurrence quantification analysis

    Science.gov (United States)

    Adeniji, A. E.; Olusola, O. I.; Njah, A. N.

    2018-02-01

    Due to the shortage in electricity supply in Nigeria, there is a need to improve the alternative power generation from wind energy by analysing the wind speed data available in some parts of the country, for a better understanding of its underlying dynamics for the purpose of good prediction and modelling. The wind speed data used in this study were collected over a period of two years by National Space Research and Development Agency (NASRDA) from five different stations in the tropics namely; Abuja (7050'02.09"N and 6004'29.97"E), Akungba (6059'05.40"N and 5035'52.23"E), Nsukka (6051'28.14"N and 7024'28.15"E), Port Harcourt (4047'05.41"N and 6059'30.62"E), and Yola (9017'33.58"N and 12023'26.69"E). In this paper, recurrence plot (RP) and recurrence quantification analysis (RQA) are applied to investigate a non-linear deterministic dynamical process and non-stationarity in hourly wind speed data from the study areas. Using RQA for each month of the two years, it is observed that wind speed data for the wet months exhibit higher chaoticity than that of the dry months for all the stations, due to strong and weak monsoonal effect during the wet and dry seasons respectively. The results show that recurrence techniques are able to identify areas and periods for which the harvest of wind energy for power generation is good (high predictability) and poor (low predictability) in the study areas. This work also validates the RQA measures (Lmax, DET and ENT) used and establishes that they are similar/related as they give similar results for the dynamical characterization of the wind speed data.

  1. Comparative study of chaotic features in hourly wind speed using recurrence quantification analysis

    Directory of Open Access Journals (Sweden)

    A. E. Adeniji

    2018-02-01

    Full Text Available Due to the shortage in electricity supply in Nigeria, there is a need to improve the alternative power generation from wind energy by analysing the wind speed data available in some parts of the country, for a better understanding of its underlying dynamics for the purpose of good prediction and modelling. The wind speed data used in this study were collected over a period of two years by National Space Research and Development Agency (NASRDA from five different stations in the tropics namely; Abuja (7050'02.09"N and 6004'29.97"E, Akungba (6059'05.40"N and 5035'52.23"E, Nsukka (6051'28.14"N and 7024'28.15"E, Port Harcourt (4047'05.41"N and 6059'30.62"E, and Yola (9017'33.58"N and 12023'26.69"E. In this paper, recurrence plot (RP and recurrence quantification analysis (RQA are applied to investigate a non-linear deterministic dynamical process and non-stationarity in hourly wind speed data from the study areas. Using RQA for each month of the two years, it is observed that wind speed data for the wet months exhibit higher chaoticity than that of the dry months for all the stations, due to strong and weak monsoonal effect during the wet and dry seasons respectively. The results show that recurrence techniques are able to identify areas and periods for which the harvest of wind energy for power generation is good (high predictability and poor (low predictability in the study areas. This work also validates the RQA measures (Lmax, DET and ENT used and establishes that they are similar/related as they give similar results for the dynamical characterization of the wind speed data.

  2. RETRAN sensitivity studies of light water reactor transients. Final report

    International Nuclear Information System (INIS)

    Burrell, N.S.; Gose, G.C.; Harrison, J.F.; Sawtelle, G.R.

    1977-06-01

    This report presents the results of sensitivity studies performed using the RETRAN/RELAP4 transient analysis code to identify critical parameters and models which influence light water reactor transient predictions. Various plant transients for both boiling water reactors and pressurized water reactors are examined. These studies represent the first detailed evaluation of the RETRAN/RELAP4 transient code capability in predicting a variety of plant transient responses. The wide range of transients analyzed in conjunction with the parameter and modeling studies performed identify several sensitive areas as well as areas requiring future study and model development

  3. Use of FFTBM by signal mirroring for sensitivity study

    International Nuclear Information System (INIS)

    Prošek, Andrej; Leskovar, Matjaž

    2015-01-01

    Highlights: • The fast Fourier transform based tool was applied for a sensitivity analysis. • The calculations of the BEMUSE programme LOFT L2-5 test were used in the study. • The most influential input parameters were identified and their influence quantified. • It was shown that FFTBM-SM is best suited for conducting quick sensitivity analyses. - Abstract: The state of the art best estimate safety analyses for nuclear reactors use best estimate thermal–hydraulic computer codes with an evaluation of the uncertainties to compare the results of calculations with acceptance criteria. The uncertainty quantification is typically accompanied by a sensitivity analysis, in which the influence of the individual contributors to the uncertainty is determined. The objective of the performed study is to demonstrate that the fast Fourier transform based method by signal mirroring (FFTBM-SM) can be very efficiently used for the sensitivity analysis when one parameter is varied at a time. The sensitivity study was conducted for the LOFT L2-5 test, which simulates the large break loss of coolant accident. The LOFT L2-5 test was analysed in the frame of the Organisation for Economic Co-operation and Development (OECD) Best Estimate Methods – Uncertainty and Sensitivity Evaluation (BEMUSE) programme, where each of the 14 participants performed a reference calculation and up to 15 sensitivity runs of the test. The results show that with the FFTBM-SM the analyst can get the time dependent picture of the input parameter influence on the results. The results suggest that FFTBM-SM is especially appropriate for a sensitivity analysis in which several calculations need to be compared

  4. EARTH, WIND AND FIRE: BUILDING METEOROLOGICALLY-SENSITIVE BIOGENIC AND WILDLAND FIRE EMISSION ESTIMATES FOR AIR QUALITY MODELS

    Science.gov (United States)

    Emission estimates are important for ensuring the accuracy of atmospheric chemical transport models. Estimates of biogenic and wildland fire emissions, because of their sensitivity to meteorological conditions, need to be carefully constructed and closely linked with a meteorolo...

  5. Study on Load-Bearing Characteristics of a New Pile Group Foundation for an Offshore Wind Turbine

    Directory of Open Access Journals (Sweden)

    Ruiqing Lang

    2014-01-01

    Full Text Available Because offshore wind turbines are high-rise structures, they transfer large horizontal loads and moments to their foundations. One of the keys to designing a foundation is determining the sensitivities and laws affecting its load-bearing capacity. In this study, this procedure was carried out for a new high-rise cap pile group foundation adapted to the loading characteristics of offshore wind turbines. The sensitivities of influential factors affecting the bearing properties were determined using an orthogonal test. Through a combination of numerical simulations and model tests, the effects of the inclination angle, length, diameter, and number of side piles on the vertical bearing capacity, horizontal bearing capacity, and bending bearing capacity were determined. The results indicate that an increase in the inclination angle of the side piles will increase the vertical bearing capacity, horizontal bearing capacity, and bending bearing capacity. An increase in the length of the side piles will increase the vertical bearing capacity and bending bearing capacity. When the length of the side piles is close to the central pile, the increase is more apparent. Finally, increasing the number of piles will increase the horizontal bearing capacity; however, the growth rate is small because of the pile group effect.

  6. Study on load-bearing characteristics of a new pile group foundation for an offshore wind turbine.

    Science.gov (United States)

    Lang, Ruiqing; Liu, Run; Lian, Jijian; Ding, Hongyan

    2014-01-01

    Because offshore wind turbines are high-rise structures, they transfer large horizontal loads and moments to their foundations. One of the keys to designing a foundation is determining the sensitivities and laws affecting its load-bearing capacity. In this study, this procedure was carried out for a new high-rise cap pile group foundation adapted to the loading characteristics of offshore wind turbines. The sensitivities of influential factors affecting the bearing properties were determined using an orthogonal test. Through a combination of numerical simulations and model tests, the effects of the inclination angle, length, diameter, and number of side piles on the vertical bearing capacity, horizontal bearing capacity, and bending bearing capacity were determined. The results indicate that an increase in the inclination angle of the side piles will increase the vertical bearing capacity, horizontal bearing capacity, and bending bearing capacity. An increase in the length of the side piles will increase the vertical bearing capacity and bending bearing capacity. When the length of the side piles is close to the central pile, the increase is more apparent. Finally, increasing the number of piles will increase the horizontal bearing capacity; however, the growth rate is small because of the pile group effect.

  7. Study on Load-Bearing Characteristics of a New Pile Group Foundation for an Offshore Wind Turbine

    Science.gov (United States)

    Liu, Run; Lian, Jijian; Ding, Hongyan

    2014-01-01

    Because offshore wind turbines are high-rise structures, they transfer large horizontal loads and moments to their foundations. One of the keys to designing a foundation is determining the sensitivities and laws affecting its load-bearing capacity. In this study, this procedure was carried out for a new high-rise cap pile group foundation adapted to the loading characteristics of offshore wind turbines. The sensitivities of influential factors affecting the bearing properties were determined using an orthogonal test. Through a combination of numerical simulations and model tests, the effects of the inclination angle, length, diameter, and number of side piles on the vertical bearing capacity, horizontal bearing capacity, and bending bearing capacity were determined. The results indicate that an increase in the inclination angle of the side piles will increase the vertical bearing capacity, horizontal bearing capacity, and bending bearing capacity. An increase in the length of the side piles will increase the vertical bearing capacity and bending bearing capacity. When the length of the side piles is close to the central pile, the increase is more apparent. Finally, increasing the number of piles will increase the horizontal bearing capacity; however, the growth rate is small because of the pile group effect. PMID:25250375

  8. Evaluation of global onshore wind energy potential and generation costs.

    Science.gov (United States)

    Zhou, Yuyu; Luckow, Patrick; Smith, Steven J; Clarke, Leon

    2012-07-17

    In this study, we develop an updated global estimate of onshore wind energy potential using reanalysis wind speed data, along with updated wind turbine technology performance, land suitability factors, cost assumptions, and explicit consideration of transmission distance in the calculation of transmission costs. We find that wind has the potential to supply a significant portion of the world energy needs, although this potential varies substantially by region and with assumptions such as on what types of land can be used to site wind farms. Total global economic wind potential under central assumptions, that is, intermediate between optimistic and pessimistic, is estimated to be approximately 119.5 petawatt hours per year (13.6 TW) at less than 9 cents/kWh. A sensitivity analysis of eight key parameters is presented. Wind potential is sensitive to a number of input parameters, particularly wind speed (varying by -70% to +450% at less than 9 cents/kWh), land suitability (by -55% to +25%), turbine density (by -60% to +80%), and cost and financing options (by -20% to +200%), many of which have important policy implications. As a result of sensitivities studied here we suggest that further research intended to inform wind supply curve development focus not purely on physical science, such as better resolved wind maps, but also on these less well-defined factors, such as land-suitability, that will also have an impact on the long-term role of wind power.

  9. Sensitivity and uncertainty studies of the CRAC2 computer code

    International Nuclear Information System (INIS)

    Kocher, D.C.; Ward, R.C.; Killough, G.G.; Dunning, D.E. Jr.; Hicks, B.B.; Hosker, R.P. Jr.; Ku, J.Y.; Rao, K.S.

    1985-05-01

    This report presents a study of the sensitivity of early fatalities, early injuries, latent cancer fatalities, and economic costs for hypothetical nuclear reactor accidents as predicted by the CRAC2 computer code (CRAC = Calculation of Reactor Accident Consequences) to uncertainties in selected models and parameters used in the code. The sources of uncertainty that were investigated in the CRAC2 sensitivity studies include (1) the model for plume rise, (2) the model for wet deposition, (3) the procedure for meteorological bin-sampling involving the selection of weather sequences that contain rain, (4) the dose conversion factors for inhalation as they are affected by uncertainties in the physical and chemical form of the released radionuclides, (5) the weathering half-time for external ground-surface exposure, and (6) the transfer coefficients for estimating exposures via terrestrial foodchain pathways. The sensitivity studies were performed for selected radionuclide releases, hourly meteorological data, land-use data, a fixed non-uniform population distribution, a single evacuation model, and various release heights and sensible heat rates. Two important general conclusions from the sensitivity and uncertainty studies are as follows: (1) The large effects on predicted early fatalities and early injuries that were observed in some of the sensitivity studies apparently are due in part to the presence of thresholds in the dose-response models. Thus, the observed sensitivities depend in part on the magnitude of the radionuclide releases. (2) Some of the effects on predicted early fatalities and early injuries that were observed in the sensitivity studies were comparable to effects that were due only to the selection of different sets of weather sequences in bin-sampling runs. 47 figs., 50 tabs

  10. Intercultural Sensitivity through Short-Term Study Abroad

    Science.gov (United States)

    Bloom, Melanie; Miranda, Arturo

    2015-01-01

    One of the foremost-cited rationales for study abroad during college is the development of a global perspective and intercultural sensitivity. Although this argument is mentioned frequently in promotional materials for study abroad, it has not yet been backed by research based on the outcomes of students' study abroad experiences. As more…

  11. Study into the Potential and Feasibility of a Standalone Solar-Wind Hybrid Electric Energy Supply System

    Energy Technology Data Exchange (ETDEWEB)

    Bekele, Getachew

    2009-12-15

    specific to the sites in question. Based on the sunshine duration data, the monthly average daily sunshine amount for each of the places has also been computed and given in a form of plot. Through additional work on the results of the calculations, the solar energy potential has been given in the form of solar radiation plots for each of the selected sites. As expected, the results indicated an abundance of solar energy potential. It is based on the promising findings of these two energy resource potentials, wind and solar, that the feasibility study for a standalone solar-wind hybrid energy supply system has proceeded, targeting the community mentioned earlier. The hybrid system consisted of Wind turbine, Photovoltaic panel, diesel generator and a bank of batteries, with a power conditioning converter included in the system.The hybrid stand-alone supply system is intended to provide electricity toa model community of 200 families with five to six family members in each. The community is equipped with a primary load, a deferrable load, a community school and a health post. An electric load which includes lighting, water pumping, a radio receiver, and some clinical equipment has been suggested. Hybrid Optimization Model for Electric Renewables, HOMER, software has been used for the analysis. The average wind speed and average solar radiation calculated from the data for all of the selected sites has been used to input into the software. The hybrid system design is approached in three different ways. The first approach is to include within the hybrid system those components which are locally available, without giving special attention to their efficiencies and proceed with the design work. The second approach is to thoroughly search the market for the best and most efficient technological products and to select the best components for the analysis. A third approach considered in an attempt of cost minimization is to see if a self-contained type of design can be a better

  12. Ethical problems and moral sensitivity in physiotherapy: a descriptive study.

    Science.gov (United States)

    Kulju, Kati; Suhonen, Riitta; Leino-Kilpi, Helena

    2013-08-01

    This study identified and described ethical problems encountered by physiotherapists in their practice and physiotherapists' moral sensitivity in ethical situations. A questionnaire-based survey was constructed to identify ethical problems, and the Moral Sensitivity Questionnaire Revised version was used to measure moral sensitivity. Physiotherapists (n = 116) working in public health services responded to the questionnaire. Based on the results, most of the physiotherapists encounter ethical problems weekly. They concern mainly financial considerations, equality and justice, professionalism, unethical conduct of physiotherapists or other professions and patients' self-determination. The dimension of moral strength was emphasised in physiotherapists' self-evaluations of their moral sensitivity. As a conclusion, ethical problems do occur not only at individual level but also at organisational and society level. Physiotherapists seem to have moral strength for speaking on behalf of the patient. Scarce resources make them feel insufficient but much could still be done to provide quality care in co-operation with other health-care professionals.

  13. Impact of an offshore wind farm on wave conditions and shoreline development

    DEFF Research Database (Denmark)

    Christensen, Erik Damgaard; Kristensen, Sten Esbjørn; Deigaard, Rolf

    2014-01-01

    the shoreline’s sensitivity to the distance from the OWF to the shoreline was studied. The effect of the reduced wind speed inside and on the lee side of the offshore wind farm was incorporated in a parameterized way in a spectral wind wave model. The shoreline impact was studied with a one-line model....

  14. Sensitivity analysis of the reactor safety study. Final report

    International Nuclear Information System (INIS)

    Parkinson, W.J.; Rasmussen, N.C.; Hinkle, W.D.

    1979-01-01

    The Reactor Safety Study (RSS) or Wash 1400 developed a methodology estimating the public risk from light water nuclear reactors. In order to give further insights into this study, a sensitivity analysis has been performed to determine the significant contributors to risk for both the PWR and BWR. The sensitivity to variation of the point values of the failure probabilities reported in the RSS was determined for the safety systems identified therein, as well as for many of the generic classes from which individual failures contributed to system failures. Increasing as well as decreasing point values were considered. An analysis of the sensitivity to increasing uncertainty in system failure probabilities was also performed. The sensitivity parameters chosen were release category probabilities, core melt probability, and the risk parameters of early fatalities, latent cancers and total property damage. The latter three are adequate for describing all public risks identified in the RSS. The results indicate reductions of public risk by less than a factor of two for factor reductions in system or generic failure probabilities as high as one hundred. There also appears to be more benefit in monitoring the most sensitive systems to verify adherence to RSS failure rates than to backfitting present reactors. The sensitivity analysis results do indicate, however, possible benefits in reducing human error rates

  15. A Study of the Solar Wind-Magnetosphere Coupling Using Neural Networks

    Science.gov (United States)

    Wu, Jian-Guo; Lundstedt, Henrik

    1996-12-01

    The interaction between solar wind plasma and interplanetary magnetic field (IMF) and Earth's magnetosphere induces geomagnetic activity. Geomagnetic storms can cause many adverse effects on technical systems in space and on the Earth. It is therefore of great significance to accurately predict geomagnetic activity so as to minimize the amount of disruption to these operational systems and to allow them to work as efficiently as possible. Dynamic neural networks are powerful in modeling the dynamics encoded in time series of data. In this study, we use partially recurrent neural networks to study the solar wind-magnetosphere coupling by predicting geomagnetic storms (as measured by the Dstindex) from solar wind measurements. The solar wind, the IMF and the geomagnetic index Dst data are hourly averaged and read from the National Space Science Data Center's OMNI database. We selected these data from the period 1963 to 1992, which cover 10552h and contain storm time periods 9552h and quiet time periods 1000h. The data are then categorized into three data sets: a training set (6634h), across-validation set (1962h), and a test set (1956h). The validation set is used to determine where the training should be stopped whereas the test set is used for neural networks to get the generalization capability (the out-of-sample performance). Based on the correlation analysis between the Dst index and various solar wind parameters (including various combinations of solar wind parameters), the best coupling functions can be found from the out-of-sample performance of trained neural networks. The coupling functions found are then used to forecast geomagnetic storms one to several hours in advance. The comparisons are made on iterating the single-step prediction several times and on making a non iterated, direct prediction. Thus, we will present the best solar wind-magnetosphere coupling functions and the corresponding prediction results. Interesting Links: Lund Space Weather and AI

  16. Study and experimental verification of control tuning strategies in a variable speed wind energy conversion system

    Energy Technology Data Exchange (ETDEWEB)

    Zaragoza, Jordi; Pou, Josep; Arias, Antoni [Electronic Engineering Dept., Technical University of Catalonia, Campus Terrassa, C. Colom 1, 08222 Terrassa (Spain); Spiteri, Cyril [Department of Industrial Electrical Power Conversion, University of Malta, Faculty of Engineering, Msida (Malta); Robles, Eider; Ceballos, Salvador [Energy Unit, Robotiker-Tecnalia Technology Corporation, Zamudio, Basque Country (Spain)

    2011-05-15

    This paper analyzes and compares different control tuning strategies for a variable speed wind energy conversion system (WECS) based on a permanent-magnet synchronous generator (PMSG). The aerodynamics of the wind turbine (WT) and a PMSG have been modeled. The control strategy used in this research is composed of three regulators, which may be based on either linear or nonlinear controllers. In this analysis, proportional-integral (PI) linear controllers have been used. Two different tuning strategies are analyzed and compared. The main goal is to enhance the overall performance by achieving a low sensitivity to disturbances and minimal overshoot under variable operating conditions. Finally, the results have been verified by an experimental WECS laboratory prototype. (author)

  17. Final Technical Report: Supporting Wind Turbine Research and Testing - Gearbox Durability Study

    Energy Technology Data Exchange (ETDEWEB)

    Matthew Malkin

    2012-04-30

    The combination of premature failure of wind turbine gearboxes and the downtime caused by those failures leads to an increase in the cost of electricity produced by the wind. There is a need for guidance to asset managers regarding how to maximize the longevity of their gearboxes in order to help keep the cost of wind energy as low as possible. A low cost of energy supports the US Department of Energy's goal of achieving 20% of the electricity in the United States produced by wind by the year 2030. DNV KEMA has leveraged our unique position in the industry as an independent third party engineering organization to study the problem of gearbox health management and develop guidance to project operators. This report describes the study. The study was conducted in four tasks. In Task 1, data that may be related to gearbox health and are normally available to wind project operators were collected for analysis. Task 2 took a more in-depth look at a small number of gearboxes to gain insight in to relevant failure modes. Task 3 brought together the previous tasks by evaluating the available data in an effort to identify data that could provide early indications of impending gearbox failure. Last, the observations from the work were collected to develop recommendations regarding gearbox health management.

  18. What hinder the further development of wind power in China?—A socio-technical barrier study

    International Nuclear Information System (INIS)

    Zhao, Zhen-Yu; Chang, Rui-Dong; Chen, Yu-Long

    2016-01-01

    Promoting wind power is a long-term strategy of China to respond to both energy shortage and environmental pollution. Stimulated by various incentive policies, wind power generation in China has achieved tremendous growth, with the cumulative installed capacity being the largest worldwide for five consecutive years since 2010. However, obstructed by various barriers, wind power provides only 2.6% of national electricity generation in China, despite the strong support from the government. From a socio-technical transition perspective, this paper aims to systematically analyze the barriers hindering the further development of China's wind power. A wind power niche model is established to illustrate the complex interactions among actors in the wind power industry and electricity supply regime. Then, qualitative content analysis is adopted to process the related evidence and data, and four categories of socio-technical barriers are identified, including technology, governance, infrastructure and culture barriers. The study shows that various interrelated barriers form a blocking mechanism which prohibits the further development of wind power in China. Policy suggestions are proposed to eliminate the barriers and further empower the wind power niche. The lesson learned from China can offer useful references for other economies to promote wind power industries of their own. - Highlights: • Use wind power niche model to illustrate the interactions among actors in the industry. • Analyze technological, governance, infrastructural and cultural barriers. • Multidimensionality and interconnectedness of the barriers are illustrated. • Policy suggestions are proposed to deal with the wind power development barriers.

  19. Climate sensitivity of marine energy

    International Nuclear Information System (INIS)

    Harrison, G.P.; Wallace, A.R.

    2005-01-01

    Marine energy has a significant role to play in lowering carbon emissions within the energy sector. Paradoxically, it may be susceptible to changes in climate that will result from rising carbon emissions. Wind patterns are expected to change and this will alter wave regimes. Despite a lack of definite proof of a link to global warming, wind and wave conditions have been changing over the past few decades. Changes in the wind and wave climate will affect offshore wind and wave energy conversion: where the resource is constrained, production and economic performance may suffer; alternatively, stormier climates may create survival issues. Here, a relatively simple sensitivity study is used to quantify how changes in mean wind speed - as a proxy for wider climate change - influence wind and wave energy production and economics. (author)

  20. Western Wind and Solar Integration Study Phase 3A: Low Levels of Synchronous Generation

    Energy Technology Data Exchange (ETDEWEB)

    Miller, Nicholas W. [GE Energy Management, Atlanta, GA (United States); Leonardi, Bruno [GE Energy Management, Atlanta, GA (United States); D' Aquila, Robert [GE Energy Management, Atlanta, GA (United States); Clark, Kara [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2015-11-17

    The stability of the North American electric power grids under conditions of high penetrations of wind and solar is a significant concern and possible impediment to reaching renewable energy goals. The 33% wind and solar annual energy penetration considered in this study results in substantial changes to the characteristics of the bulk power system. This includes different power flow patterns, different commitment and dispatch of existing synchronous generation, and different dynamic behavior from wind and solar generation. The Western Wind and Solar Integration Study (WWSIS), sponsored by the U.S. Department of Energy, is one of the largest regional solar and wind integration studies to date. In multiple phases, it has explored different aspects of the question: Can we integrate large amounts of wind and solar energy into the electric power system of the West? The work reported here focused on the impact of low levels of synchronous generation on the transient stability performance in one part of the region in which wind generation has displaced synchronous thermal generation under highly stressed, weak system conditions. It is essentially an extension of WWSIS-3. Transient stability, the ability of the power system to maintain synchronism among all elements following disturbances, is a major constraint on operations in many grids, including the western U.S. and Texas systems. These constraints primarily concern the performance of the large-scale bulk power system. But grid-wide stability concerns with high penetrations of wind and solar are still not thoroughly understood. This work focuses on 'traditional' fundamental frequency stability issues, such as maintaining synchronism, frequency, and voltage. The objectives of this study are to better understand the implications of low levels of synchronous generation and a weak grid on overall system performance by: 1) Investigating the Western Interconnection under conditions of both high renewable

  1. Autocorrelation Study of Solar Wind Plasma and IMF Properties as Measured by the MAVEN Spacecraft

    Science.gov (United States)

    Marquette, Melissa L.; Lillis, Robert J.; Halekas, J. S.; Luhmann, J. G.; Gruesbeck, J. R.; Espley, J. R.

    2018-04-01

    It has long been a goal of the heliophysics community to understand solar wind variability at heliocentric distances other than 1 AU, especially at ˜1.5 AU due to not only the steepening of solar wind stream interactions outside 1 AU but also the number of missions available there to measure it. In this study, we use 35 months of solar wind and interplanetary magnetic field (IMF) data taken at Mars by the Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft to conduct an autocorrelation analysis of the solar wind speed, density, and dynamic pressure, which is derived from the speed and density, as well as the IMF strength and orientation. We found that the solar wind speed is coherent, that is, has an autocorrelation coefficient above 1/e, over roughly 56 hr, while the density and pressure are coherent over smaller intervals of roughly 25 and 20 hr, respectively, and that the IMF strength is coherent over time intervals of approximately 20 hr, while the cone and clock angles are considerably less steady but still somewhat coherent up to time lags of roughly 16 hr. We also found that when the speed, density, pressure, or IMF strength is higher than average, the solar wind or IMF becomes uncorrelated more quickly, while when they are below average, it tends to be steadier. This analysis allows us to make estimates of the values of solar wind plasma and IMF parameters when they are not directly measured and provide an approximation of the error associated with that estimate.

  2. VLTI-AMBER Velocity-Resolved Aperture-Synthesis Imaging of Eta Carinae with a Spectral Resolution of 12 000: Studies of the Primary Star Wind and Innermost Wind-Wind Collision Zone

    Science.gov (United States)

    Weigelt, G.; Hofmann, K.-H.; Schertl, D.; Clementel, N.; Corcoran, M. F.; Damineli, A.; de Wit, W.-J.; Grellmann, R.; Groh, J.; Guieu, S.; hide

    2016-01-01

    The mass loss from massive stars is not understood well. Eta Carinae is a unique object for studying the massive stellar wind during the luminous blue variable phase. It is also an eccentric binary with a period of 5.54 yr. The nature of both stars is uncertain, although we know from X-ray studies that there is a wind-wind collision whose properties change with orbital phase. Aims. We want to investigate the structure and kinematics of Car's primary star wind and wind-wind collision zone with a high spatial resolution of approx.6 mas (approx.14 au) and high spectral resolution of R = 12 000. Methods. Observations of Car were carried out with the ESO Very Large Telescope Interferometer (VLTI) and the AMBER instrument between approximately five and seven months before the August 2014 periastron passage. Velocity-resolved aperture-synthesis images were reconstructed from the spectrally dispersed interferograms. Interferometric studies can provide information on the binary orbit, the primary wind, and the wind collision. Results. We present velocity-resolved aperture-synthesis images reconstructed in more than 100 di erent spectral channels distributed across the Br(gamma) 2.166 micron emission line. The intensity distribution of the images strongly depends on wavelength. At wavelengths corresponding to radial velocities of approximately -140 to -376 km/s measured relative to line center, the intensity distribution has a fan-shaped structure. At the velocity of -277 km/s, the position angle of the symmetry axis of the fan is 126. The fan-shaped structure extends approximately 8.0 mas (approx.18:8 au) to the southeast and 5.8 mas (approx.13:6 au) to the northwest, measured along the symmetry axis at the 16% intensity contour. The shape of the intensity distributions suggests that the obtained images are the first direct images of the innermost wind-wind collision zone. Therefore, the observations provide velocity-dependent image structures that can be used to test three

  3. Development of a representative model of a wind turbine in order to study the installation of several machines on a wind park

    International Nuclear Information System (INIS)

    Jourieh, M.

    2007-12-01

    This thesis is devoted to the study of aerodynamics in wind turbines. It is divided into two main parts, one is experimental, and the other deals with modelling and numerical simulation. The velocity field downstream from a three-bladed wind turbine with a horizontal axis is explored in the wind tunnel at ENSAM-Paris. Two measurement techniques are used: hot wire anemometry and Particle Image Velocimetry (PIV). Experimental work gives a clear idea of the structure of the near wake and provides useful data to validate the numerical simulations and the hybrid models which are studied in this thesis. In the work concerning numerical simulation, two hybrid models are defined and implemented: a model of actuator disc and a model of actuator cylinder, coupled with a simulation based on the numerical resolution of the Navier-Stokes equations. These models are validated by the power of the wind turbine and on the velocity field in the near wake of the rotor. The numerical results are compared with the experimental data resulting from the tests carried out by the NREL for NREL phase II and VI cases. The experimental and numerical velocity fields are also compared in the wake of a wind turbine Rutland 503. In both validation cases, power and wake, the experimental data are in accordance with the results provided by the hybrid models. After this validation, the interaction between several wind turbines is studied and quantified. The tested hybrid models are also used to study the interaction between identical wind turbines placed one behind the other. The obtained results highlight the effect of spacing between the machines as well as the effect of free stream velocity. (author)

  4. Using artificial neural networks to determine the location of wind farms. Miedzna district case study

    Directory of Open Access Journals (Sweden)

    Pokonieczny Krzysztof

    2016-09-01

    Full Text Available The article concerns issues pertaining to of selecting suitable areas for wind farms. The basic assumption of the study was to take into account both criteria related to the profitability of this type of power plant, as well as public interest, which means the harmonious and not burdensome functioning of these installations for local communities. The problem of wind farm localization may be solved by the application of artificial neural networks (ANN, which are a computational intelligence element. In the conducted analysis, the possibility of wind farm localization was considered for the primary grid field with dimensions of 100 by 100 m. To prepare the training set, topographic vector data from the VMap L2 and SRTM (Shuttle Radar Topography Mission digital terrain model were used. For each 100-meter × 100-meter grid, the input data was prepared, consisting of the factors which are important from the point of view of wind farm localization (forests, rivers, built-up areas etc.. Studies show that a properly trained neural network (using a representative number of samples and for the appropriate architecture, allows to process automation area classification in terms of placement on the wind turbines.

  5. Study on Unified Chaotic System-Based Wind Turbine Blade Fault Diagnostic System

    Science.gov (United States)

    Kuo, Ying-Che; Hsieh, Chin-Tsung; Yau, Her-Terng; Li, Yu-Chung

    At present, vibration signals are processed and analyzed mostly in the frequency domain. The spectrum clearly shows the signal structure and the specific characteristic frequency band is analyzed, but the number of calculations required is huge, resulting in delays. Therefore, this study uses the characteristics of a nonlinear system to load the complete vibration signal to the unified chaotic system, applying the dynamic error to analyze the wind turbine vibration signal, and adopting extenics theory for artificial intelligent fault diagnosis of the analysis signal. Hence, a fault diagnostor has been developed for wind turbine rotating blades. This study simulates three wind turbine blade states, namely stress rupture, screw loosening and blade loss, and validates the methods. The experimental results prove that the unified chaotic system used in this paper has a significant effect on vibration signal analysis. Thus, the operating conditions of wind turbines can be quickly known from this fault diagnostic system, and the maintenance schedule can be arranged before the faults worsen, making the management and implementation of wind turbines smoother, so as to reduce many unnecessary costs.

  6. A Feasibility Study to Evaluate Wind Energy Potential on the Navajo Nation

    Energy Technology Data Exchange (ETDEWEB)

    Terry Battiest

    2012-11-30

    The project, A Feasibility Study to Evaluate Wind Energy Potential on the Navajo Nation, is funded under a solicitation issued by the U.S. Department of Energy Tribal Energy Program. Funding provided by the grant allowed the Navajo Nation to measure wind potential at two sites, one located within the boundaries of the Navajo Nation and the other off-reservation during the project period (September 5, 2005 - September 30, 2009). The recipient for the grant award is the Navajo Tribal Utility Authority (NTUA). The grant allowed the Navajo Nation and NTUA manage the wind feasibility from initial site selection through the decision-making process to commit to a site for wind generation development. The grant activities help to develop human capacity at NTUA and help NTUA to engage in renewable energy generation activities, including not only wind but also solar and biomass. The final report also includes information about development activities regarding the sited included in the grant-funded feasibility study.

  7. Simulation study of solar wind push on a charged wire: basis of solar wind electric sail propulsion

    Directory of Open Access Journals (Sweden)

    P. Janhunen

    2007-03-01

    Full Text Available One possibility for propellantless propulsion in space is to use the momentum flux of the solar wind. A way to set up a solar wind sail is to have a set of thin long wires which are kept at high positive potential by an onboard electron gun so that the wires repel and deflect incident solar wind protons. The efficiency of this so-called electric sail depends on how large force a given solar wind exerts on a wire segment and how large electron current the wire segment draws from the solar wind plasma when kept at a given potential. We use 1-D and 2-D electrostatic plasma simulations to calculate the force and present a semitheoretical formula which captures the simulation results. We find that under average solar wind conditions at 1 AU the force per unit length is (5±1×10−8 N/m for 15 kV potential and that the electron current is accurately given by the well-known orbital motion limited (OML theory cylindrical Langmuir probe formula. Although the force may appear small, an analysis shows that because of the very low weight of a thin wire per unit length, quite high final speeds (over 50 km/s could be achieved by an electric sailing spacecraft using today's flight-proved components. It is possible that artificial electron heating of the plasma in the interaction region could increase the propulsive effect even further.

  8. Simulation study of solar wind push on a charged wire: basis of solar wind electric sail propulsion

    Directory of Open Access Journals (Sweden)

    P. Janhunen

    2007-03-01

    Full Text Available One possibility for propellantless propulsion in space is to use the momentum flux of the solar wind. A way to set up a solar wind sail is to have a set of thin long wires which are kept at high positive potential by an onboard electron gun so that the wires repel and deflect incident solar wind protons. The efficiency of this so-called electric sail depends on how large force a given solar wind exerts on a wire segment and how large electron current the wire segment draws from the solar wind plasma when kept at a given potential. We use 1-D and 2-D electrostatic plasma simulations to calculate the force and present a semitheoretical formula which captures the simulation results. We find that under average solar wind conditions at 1 AU the force per unit length is (5±1×10−8 N/m for 15 kV potential and that the electron current is accurately given by the well-known orbital motion limited (OML theory cylindrical Langmuir probe formula. Although the force may appear small, an analysis shows that because of the very low weight of a thin wire per unit length, quite high final speeds (over 50 km/s could be achieved by an electric sailing spacecraft using today's flight-proved components. It is possible that artificial electron heating of the plasma in the interaction region could increase the propulsive effect even further.

  9. Field and numerical study of wind and surface waves at short fetches

    Science.gov (United States)

    Baydakov, Georgy; Kuznetsova, Alexandra; Sergeev, Daniil; Papko, Vladislav; Kandaurov, Alexander; Vdovin, Maxim; Troitskaya, Yuliya

    2016-04-01

    Measurements were carried out in 2012-2015 from May to October in the waters of Gorky Reservoir belonging to the Volga Cascade. The methods of the experiment focus on the study of airflow in the close proximity to the water surface. The sensors were positioned at the oceanographic Froude buoy including five two-component ultrasonic sensors WindSonic by Gill Instruments at different levels (0.1, 0.85, 1.3, 2.27, 5.26 meters above the mean water surface level), one water and three air temperature sensors, and three-channel wire wave gauge. One of wind sensors (0.1 m) was located on the float tracking the waveform for measuring the wind speed in the close proximity to the water surface. Basic parameters of the atmospheric boundary layer (the friction velocity u∗, the wind speed U10 and the drag coefficient CD) were calculated from the measured profiles of wind speed. Parameters were obtained in the range of wind speeds of 1-12 m/s. For wind speeds stronger than 4 m/s CD values were lower than those obtained before (see eg. [1,2]) and those predicted by the bulk parameterization. However, for weak winds (less than 3 m/s) CD values considerably higher than expected ones. The new parameterization of surface drag coefficient was proposed on the basis of the obtained data. The suggested parameterization of drag coefficient CD(U10) was implemented within wind input source terms in WAVEWATCH III [3]. The results of the numerical experiments were compared with the results obtained in the field experiments on the Gorky Reservoir. The use of the new drag coefficient improves the agreement in significant wave heights HS [4]. At the same time, the predicted mean wave periods are overestimated using both built-in source terms and adjusted source terms. We associate it with the necessity of the adjusting of the DIA nonlinearity model in WAVEWATCH III to the conditions of the middle-sized reservoir. Test experiments on the adjusting were carried out. The work was supported by the

  10. Impact of wind turbine sound on general health, sleep disturbance and annoyance of workers: a pilot- study in Manjil wind farm, Iran.

    Science.gov (United States)

    Abbasi, Milad; Monazzam, Mohammad Reza; Akbarzadeh, Arash; Zakerian, Seyyed Abolfazl; Ebrahimi, Mohammad Hossein

    2015-01-01

    The wind turbine's sound seems to have a proportional effect on health of people living near to wind farms. This study aimed to investigate the effect of noise emitted from wind turbines on general health, sleep and annoyance among workers of manjil wind farm, Iran. A total number of 53 workers took part in this study. Based on the type of job, they were categorized into three groups of maintenance, security and office staff. The persons' exposure at each job-related group was measured by eight-hour equivalent sound level (LAeq, 8 h). A Noise annoyance scale, Epworth sleepiness scale and 28-item general health questionnaire was used for gathering data from workers. The data were analyzed through Multivariate Analysis of variance (MANOVA) test, Pillai's Trace test, Paired comparisons analysis and Multivariate regression test were used in the R software. The results showed that, response variables (annoyance, sleep disturbance and health) were significantly different between job groups. The results also indicated that sleep disturbance as well as noise exposure had a significant effect on general health. Noise annoyance and distance from wind turbines could significantly explain about 44.5 and 34.2 % of the variance in sleep disturbance and worker's general health, respectively. General health was significantly different in different age groups while age had no significant impact on sleep disturbance. The results were reverse for distance because it had no significant impact on health, but sleep disturbance was significantly affected. We came to this conclusion that wind turbines noise can directly impact on annoyance, sleep and health. This type of energy generation can have potential health risks for wind farm workers. However, further research is needed to confirm the results of this study.

  11. Aspartame sensitivity? A double blind randomised crossover study.

    Directory of Open Access Journals (Sweden)

    Thozhukat Sathyapalan

    Full Text Available Aspartame is a commonly used intense artificial sweetener, being approximately 200 times sweeter than sucrose. There have been concerns over aspartame since approval in the 1980s including a large anecdotal database reporting severe symptoms. The objective of this study was to compare the acute symptom effects of aspartame to a control preparation.This was a double-blind randomized cross over study conducted in a clinical research unit in United Kingdom. Forty-eight individual who has self reported sensitivity to aspartame were compared to 48 age and gender matched aspartame non-sensitive individuals. They were given aspartame (100mg-containing or control snack bars randomly at least 7 days apart. The main outcome measures were acute effects of aspartame measured using repeated ratings of 14 symptoms, biochemistry and metabonomics.Aspartame sensitive and non-sensitive participants differed psychologically at baseline in handling feelings and perceived stress. Sensitive participants had higher triglycerides (2.05 ± 1.44 vs. 1.26 ± 0.84mmol/L; p value 0.008 and lower HDL-C (1.16 ± 0.34 vs. 1.35 ± 0.54 mmol/L; p value 0.04, reflected in 1H NMR serum analysis that showed differences in the baseline lipid content between the two groups. Urine metabonomic studies showed no significant differences. None of the rated symptoms differed between aspartame and control bars, or between sensitive and control participants. However, aspartame sensitive participants rated more symptoms particularly in the first test session, whether this was placebo or control. Aspartame and control bars affected GLP-1, GIP, tyrosine and phenylalanine levels equally in both aspartame sensitive and non-sensitive subjects.Using a comprehensive battery of psychological tests, biochemistry and state of the art metabonomics there was no evidence of any acute adverse responses to aspartame. This independent study gives reassurance to both regulatory bodies and the public that

  12. Aspartame sensitivity? A double blind randomised crossover study.

    Science.gov (United States)

    Sathyapalan, Thozhukat; Thatcher, Natalie J; Hammersley, Richard; Rigby, Alan S; Courts, Fraser L; Pechlivanis, Alexandros; Gooderham, Nigel J; Holmes, Elaine; le Roux, Carel W; Atkin, Stephen L

    2015-01-01

    Aspartame is a commonly used intense artificial sweetener, being approximately 200 times sweeter than sucrose. There have been concerns over aspartame since approval in the 1980s including a large anecdotal database reporting severe symptoms. The objective of this study was to compare the acute symptom effects of aspartame to a control preparation. This was a double-blind randomized cross over study conducted in a clinical research unit in United Kingdom. Forty-eight individual who has self reported sensitivity to aspartame were compared to 48 age and gender matched aspartame non-sensitive individuals. They were given aspartame (100mg)-containing or control snack bars randomly at least 7 days apart. The main outcome measures were acute effects of aspartame measured using repeated ratings of 14 symptoms, biochemistry and metabonomics. Aspartame sensitive and non-sensitive participants differed psychologically at baseline in handling feelings and perceived stress. Sensitive participants had higher triglycerides (2.05 ± 1.44 vs. 1.26 ± 0.84mmol/L; p value 0.008) and lower HDL-C (1.16 ± 0.34 vs. 1.35 ± 0.54 mmol/L; p value 0.04), reflected in 1H NMR serum analysis that showed differences in the baseline lipid content between the two groups. Urine metabonomic studies showed no significant differences. None of the rated symptoms differed between aspartame and control bars, or between sensitive and control participants. However, aspartame sensitive participants rated more symptoms particularly in the first test session, whether this was placebo or control. Aspartame and control bars affected GLP-1, GIP, tyrosine and phenylalanine levels equally in both aspartame sensitive and non-sensitive subjects. Using a comprehensive battery of psychological tests, biochemistry and state of the art metabonomics there was no evidence of any acute adverse responses to aspartame. This independent study gives reassurance to both regulatory bodies and the public that acute ingestion of

  13. Poetics of Narrative: A Study on the "Sons of the Wind" by Laila Al Atrash

    Science.gov (United States)

    Al Zuraigat, Asma M.; Zeidanin, Hussein Hasan

    2015-01-01

    This study aims at identifying the poetic devices overlapping with the genre of fiction in Laila Al Atrash's novel "The Sons of the Wind". The devices the study explores are the poetics of the title, poetics of the prologue and poetics of the language upon which the writer relies to support her point of view about the topics and issues…

  14. Wind farm layout optimization in complex terrain: A preliminary study on a Gaussian hill

    DEFF Research Database (Denmark)

    Feng, Ju; Shen, Wen Zhong

    2014-01-01

    this problem for WFs in flat terrain or offshore has been investigated in many studies, it is still a challenging problem for WFs in complex terrain. In this preliminary study, the wind flow conditions of complex terrain without WTs are first obtained from computational fluid dynamics (CFD) simulation...

  15. Preliminary study of the offshore wind and temperature profiles at the North of the Yucatan Peninsula

    International Nuclear Information System (INIS)

    Soler-Bientz, Rolando; Watson, Simon; Infield, David; Ricalde-Cab, Lifter

    2011-01-01

    Highlights: → This is the first study that reports the properties of the vertical wind resources for the offshore conditions of the North coast of the Yucatan Peninsula. → A significant and detailed analysis of the thermal patterns has revealed a complex structure of the atmospheric boundary layer close to the shore. → The structure of the diurnal wind patterns was assessed to produce an important reference for the wind resource availability in the study region. → It was identified that the sea breeze blows in directions almost parallel to the shoreline of the North of the Yucatan Peninsula during the majority of the 24 h cycle. → The analysis of the offshore data revealed a persistent non-uniform surface boundary layer developed as result of the advection of a warn air over a cold sea. - Abstract: The stability conditions in the atmospheric boundary layer, the intensity of the wind speeds and consequently the energy potential available in offshore conditions are highly influenced by the distance from the coastline and the differences between the air and sea temperatures. This paper presents a preliminary research undertook to study the offshore wind and temperature vertical profiles at the North-West of the Yucatan Peninsula coast. Ten minute averages were recorded over approximately 2 years from sensors installed at two different heights on a communication tower located at 6.65 km from the coastline. The results have shown that the offshore wind is thermally driven by differential heating of land and sea producing breeze patterns which veer to blow parallel to the coast under the action of the Coriolis force. To investigate further, a dataset of hourly sea surface temperatures derived from GEOS Satellite thermal maps was combined with the onsite measured data to study its effect on the vertical temperature profile. The results suggested largely unstable conditions and the potentially development of a shallow Stable Internal Boundary Layer which occurs

  16. Sensitivity analysis and power for instrumental variable studies.

    Science.gov (United States)

    Wang, Xuran; Jiang, Yang; Zhang, Nancy R; Small, Dylan S

    2018-03-31

    In observational studies to estimate treatment effects, unmeasured confounding is often a concern. The instrumental variable (IV) method can control for unmeasured confounding when there is a valid IV. To be a valid IV, a variable needs to be independent of unmeasured confounders and only affect the outcome through affecting the treatment. When applying the IV method, there is often concern that a putative IV is invalid to some degree. We present an approach to sensitivity analysis for the IV method which examines the sensitivity of inferences to violations of IV validity. Specifically, we consider sensitivity when the magnitude of association between the putative IV and the unmeasured confounders and the direct effect of the IV on the outcome are limited in magnitude by a sensitivity parameter. Our approach is based on extending the Anderson-Rubin test and is valid regardless of the strength of the instrument. A power formula for this sensitivity analysis is presented. We illustrate its usage via examples about Mendelian randomization studies and its implications via a comparison of using rare versus common genetic variants as instruments. © 2018, The International Biometric Society.

  17. Wind tunnel study of natural ventilation of building integrated photovoltaics double skin façade

    Directory of Open Access Journals (Sweden)

    Hudişteanu Sebastian Valeriu

    2018-01-01

    Full Text Available The paper presents a wind tunnel experimental analysis of a small-scale building model (1:30. The objective of the study is to determine the wind influence on the ventilation of a double skin façade channel (DSF and the cooling effect over integrated photovoltaic panels. The tests were achieved by conceiving and implementation of an experimental program using a wind tunnel with atmospheric boundary layer. The effect of the wind over the ventilation of the horizontal channels of double skin façades is evaluated for different incident velocities. The results are generalized for the average steady state values of the velocities analysed. The experimental results put in evidence the correlation between the reference wind velocity and the dynamics of the air movement inside the double skin façade. These values are used to determine the convective heat transfer and the cooling effect of the air streams inside the channel upon the integrated photovoltaic panels. The decrease of the photovoltaic panels temperature determines a raise of 11% in efficiency and power generated.

  18. Wind tunnel study of natural ventilation of building integrated photovoltaics double skin façade

    Science.gov (United States)

    Hudişteanu, Sebastian Valeriu; Popovici, Cătălin George; Cherecheş, Nelu-Cristian

    2018-02-01

    The paper presents a wind tunnel experimental analysis of a small-scale building model (1:30). The objective of the study is to determine the wind influence on the ventilation of a double skin façade channel (DSF) and the cooling effect over integrated photovoltaic panels. The tests were achieved by conceiving and implementation of an experimental program using a wind tunnel with atmospheric boundary layer. The effect of the wind over the ventilation of the horizontal channels of double skin façades is evaluated for different incident velocities. The results are generalized for the average steady state values of the velocities analysed. The experimental results put in evidence the correlation between the reference wind velocity and the dynamics of the air movement inside the double skin façade. These values are used to determine the convective heat transfer and the cooling effect of the air streams inside the channel upon the integrated photovoltaic panels. The decrease of the photovoltaic panels temperature determines a raise of 11% in efficiency and power generated.

  19. The discourse of "social licence to operate": case study of the Australian wind industry

    Directory of Open Access Journals (Sweden)

    Nina L. Hall

    2014-12-01

    Full Text Available Social Licence to Operate is a concept from the mining industry that reflects the ongoing acceptance or approval for a development granted by local stakeholders. It is now being applied by wind farm developers. Using the Australian wind industry as a case study, this discourse analysis examined how Social Licence to Operate is perceived and operationalised, and the key themes in this conceptual and applied discourse. Discourse analysis acknowledges that language choices are not accidental and discourse reflects power relationships. The wind industry representatives interviewed considered power over the Social Licence to Operate was shared with community stakeholders. They recognised the stakeholders' power to delay or prevent projects, but rejected the notion that every stakeholder group should have veto power. Social Licence to Operate is seen by the wind industry through a business-oriented perspective, with an emphasis on business risk, and they describe the opposition to wind farms by invoking a metaphor of "battle". The industry respondents described Social Licence to Operate as incorporating the values of trust, transparency and participation—which all contribute to creating "authentic" relationships. These findings can inform Social Licence to Operate research, engagement practices, and also encourage reflection by industry representatives on their implicit intentions for stakeholder engagement.

  20. Wind-induced transmission tower foundation loads. A field study-design code comparison

    Energy Technology Data Exchange (ETDEWEB)

    Savory, E. [Department of Mechanical and Materials Engineering, University of Western Ontario, London, Ont. (Canada); Parke, G.A.R.; Disney, P.; Toy, N. [School of Engineering, University of Surrey, Guildford, Surrey GU2 7XH (United Kingdom)

    2008-06-15

    This paper presents a comparison between the wind-induced foundation loads measured on a type L6 transmission line tower during a field study in the UK and those computed using the UK Code of Practice for lattice tower and transmission line design (BS8100). In this work, the Code provisions have been generalised to give the wind-induced strain in each of the tower legs immediately above the foundation as a function of wind direction and wind speed at the top of the tower. The complete data set from the field monitoring has been decomposed to provide a similar formulation for comparison purposes. The analysis shows excellent agreement between the Code calculations and the measured results, within the overall accuracy of the field data. This indicates that, at least for the tower type examined here, the existing design Code provides a reliable transformation of the local wind speed at the top of the tower into tension and compression loads on the foundations. (author)

  1. Experimental and Numerical Study of the Aerodynamic Characteristics of an Archimedes Spiral Wind Turbine Blade

    Directory of Open Access Journals (Sweden)

    Kyung Chun Kim

    2014-11-01

    Full Text Available A new type of horizontal axis wind turbine adopting the Archimedes spiral blade is introduced for urban-use. Based on the angular momentum conservation law, the design formula for the blade was derived using a variety of shape factors. The aerodynamic characteristics and performance of the designed Archimedes wind turbine were examined using computational fluid dynamics (CFD simulations. The CFD simulations showed that the new type of wind turbine produced a power coefficient (Cp of approximately 0.25, which is relatively high compared to other types of urban-usage wind turbines. To validate the CFD results, experimental studies were carried out using a scaled-down model. The instantaneous velocity fields were measured using the two-dimensional particle image velocimetry (PIV method in the near field of the blade. The PIV measurements revealed the presence of dominant vortical structures downstream the hub and near the blade tip. The interaction between the wake flow at the rotor downstream and the induced velocity due to the tip vortices were strongly affected by the wind speed and resulting rotational speed of the blade. The mean velocity profiles were compared with those predicted by the steady state and unsteady state CFD simulations. The unsteady CFD simulation agreed better with those of the PIV experiments than the steady state CFD simulations.

  2. Wind Tunnel Study on Flows over Various Two-dimensional Idealized Urban-liked Surfaces

    Science.gov (United States)

    Ho, Yat-Kiu; Liu, Chun-Ho

    2013-04-01

    Extensive human activities (e.g. increased traffic emissions) emit a wide range of pollutants resulting in poor urban area air quality. Unlike open, flat and homogenous rural terrain, urban surface is complicated by the presence of buildings, obstacles and narrow streets. The irregular urban surfaces thus form a random roughness that further modifies the near-surface flows and pollutant dispersion. In this study, a physical modelling approach is employed to commence a series of wind tunnel experiments to study the urban-area air pollution problems. The flow characteristics over different hypothetical urban roughness surfaces were studied in a wind tunnel in isothermal conditions. Preliminary experiments were conducted based on six types of idealized two-dimensional (2D) street canyon models with various building-height-to-street-width (aspect) ratios (ARs) 1, 1/2, 1/4, 1/8, 1/10 and 1/12. The main instrumentation is an in-house 90o X-hotwire anemometry. In each set of configuration, a sampling street canyon was selected near the end of the streamwise domain. Its roof level, i.e. the transverse between the mid points of the upstream and downstream buildings, was divided into eight segments. The measurements were then recorded on the mid-plane of the spannwise domain along the vertical profile (from building roof level to the ceiling of wind tunnel) of the eight segments. All the data acquisition processes were handled by the NI data acquisition modules, NI 9239 and CompactDAQ-9188 hardware. Velocity calculation was carried out in the post-processing stage on a digital computer. The two-component flow velocities and velocity fluctuations were calculated at each sampling points, therefore, for each model, a streamwise average of eight vertical profiles of mean velocity and velocity fluctuations was presented. A plot of air-exchange rate (ACH) against ARs was also presented in order to examine the ventilation performance of different tested models. Preliminary results

  3. Comparative numerical and experimental study of two combined wind and wave energy concepts

    Directory of Open Access Journals (Sweden)

    Zhen Gao

    2016-01-01

    Full Text Available With a successful and rapid development of offshore wind industry and increased research activities on wave energy conversion in recent years, there is an interest in investigating the technological and economic feasibility of combining offshore wind turbines (WTs with wave energy converters (WECs. In the EU FP7 MARINA Platform project, three floating combined concepts, namely the spar torus combination (STC, the semi-submersible flap combination (SFC and the oscillating water column (OWC array with a wind turbine, were selected and studied in detail by numerical and experimental methods. This paper summarizes the numerical modeling and analysis of the two concepts: STC and SFC, the model tests at a 1:50 scale under simultaneous wave and wind excitation, as well as the comparison between the numerical and experimental results. Both operational and survival wind and wave conditions were considered. The numerical analysis was based on a time-domain global model using potential flow theory for hydrodynamics and blade element momentum theory (for SFC or simplified thrust force model (for STC for aerodynamics. Different techniques for model testing of combined wind and wave concepts were discussed with focus on modeling of wind turbines by disk or redesigned small-scale rotor and modeling of power take-off (PTO system for wave energy conversion by pneumatic damper or hydraulic rotary damper. In order to reduce the uncertainty due to scaling, the numerical analysis was performed at model scale and both the numerical and experimental results were then up-scaled to full scale for comparison. The comparison shows that the current numerical model can well predict the responses (motions, PTO forces, power production of the combined concepts for most of the cases. However, the linear hydrodynamic model is not adequate for the STC concept in extreme wave conditions with the torus fixed to the spar at the mean water level for which the wave slamming on the

  4. Cherokee Nation Enterprises Wind Energy Feasibility Study Final Report to U.S. DOE

    Energy Technology Data Exchange (ETDEWEB)

    Carol E. Wyatt

    2006-04-30

    CNE has conducted a feasibility study on the Chilocco property in north-central Oklahoma since the grant award on July 20, 2003. This study has concluded that there is sufficient wind for a wind farm and that with the Production Tax Credits and Green Tags, there will be sufficient energy to, not only cover the costs of the Nation’s energy needs, but to provide a profit. CNE has developed a wind energy team and is working independently and with industry partners to bring its renewable energy resources to the marketplace. We are continuing with the next phase in conducting avian, cultural and transmission studies, as well as continuing to measure the wind with the SoDAR unit. Cherokee Nation Enterprises, Inc. is a wholly-owned corporation under Cherokee Nation and has managed the Department of Energy grant award since July 20, 2003. In summary, we have determined there is sufficient wind for a wind farm at the Chilocco property where Cherokee Nation owns approximately 4,275 acres. The primary goal would be more of a savings in light of the electricity used by Cherokee Nation and its entities which totals an estimated eight million dollars per year. Cherokee Nation Enterprises (CNE), working independently and with industry partners, plans to bring its renewable energy resources into the marketplace through a well-documented understanding of our undeveloped resource. Our plan is to cultivate this resource in a way that will ensure the development and use for our energy will be in an environmentally and culturally acceptable form.

  5. Sensitivity and uncertainty studies of the CRAC2 computer code

    International Nuclear Information System (INIS)

    Kocher, D.C.; Ward, R.C.; Killough, G.G.; Dunning, D.E. Jr.; Hicks, B.B.; Hosker, R.P. Jr.; Ku, J.Y.; Rao, K.S.

    1987-01-01

    The authors have studied the sensitivity of health impacts from nuclear reactor accidents, as predicted by the CRAC2 computer code, to the following sources of uncertainty: (1) the model for plume rise, (2) the model for wet deposition, (3) the meteorological bin-sampling procedure for selecting weather sequences with rain, (4) the dose conversion factors for inhalation as affected by uncertainties in the particle size of the carrier aerosol and the clearance rates of radionuclides from the respiratory tract, (5) the weathering half-time for external ground-surface exposure, and (6) the transfer coefficients for terrestrial foodchain pathways. Predicted health impacts usually showed little sensitivity to use of an alternative plume-rise model or a modified rain-bin structure in bin-sampling. Health impacts often were quite sensitive to use of an alternative wet-deposition model in single-trial runs with rain during plume passage, but were less sensitive to the model in bin-sampling runs. Uncertainties in the inhalation dose conversion factors had important effects on early injuries in single-trial runs. Latent cancer fatalities were moderately sensitive to uncertainties in the weathering half-time for ground-surface exposures, but showed little sensitivity to the transfer coefficients for terrestrial foodchain pathways. Sensitivities of CRAC2 predictions to uncertainties in the models and parameters also depended on the magnitude of the source term, and some of the effects on early health effects were comparable to those that were due only to selection of different sets of weather sequences in bin-sampling

  6. Comparison of two LES codes for wind turbine wake studies

    DEFF Research Database (Denmark)

    Chivaee, Hamid Sarlak; Pierella, F.; Mikkelsen, Robert Flemming

    2014-01-01

    of this paper is to investigate on two CFD solvers, the DTU's in-house code, EllipSys3D and the open-sourse toolbox, OpenFoam, for a set of actuator line based LES computations. Two types of simulations are performed: the wake behind a signle rotor and the wake behind a cluster of three inline rotors. Results...... are compared in terms of velocity deficit, turbulence kinetic energy and eddy viscosity. It is seen that both codes predict similar near-wake flow structures with the exception of OpenFoam's simulations without the subgrid-scale model. The differences begin to increase with increasing the distance from...... of the wake structures and more homogenuous flow structures. It is finally observed that OpenFoam computations are more sensitive to the SGS models....

  7. Feasibility Study of Energy Storage Systems in Wind/Diesel Applications Using the HOMER Model

    Directory of Open Access Journals (Sweden)

    Andrew Stiel

    2012-10-01

    Full Text Available With an increased focus on solutions to the ensuing “climate crisis”, the need for energy storage systems is becoming increasingly important as a means to increase the penetration of renewable technologies such as wind energy. The Vanadium Redox Battery is one such energy storage system showing considerable potential owing to its flexibility in power output and capacity, high efficiency and long operating life. This study models the use of the Vanadium Redox Battery as an integration technology in realistic large-scale remote wind/diesel power systems using the HOMER Micropower Optimization Model computer program developed by the US National Renewable Energy Laboratory. Results from this modelling demonstrate the significant financial and environmental benefits to be gained in installing energy storage in a wind farm. The storage system considered here was a Vanadium Redox Battery.

  8. Design study of high-temperature superconducting generators for wind power systems

    Energy Technology Data Exchange (ETDEWEB)

    Maki, N [Technova Inc. 13th Fl. Imperial Hotel Tower, 1-chome, Chiyoda-ku, Tokyo 100-0011 (Japan)], E-mail: naokmaki@technova.co.jp

    2008-02-15

    Design study on high-temperature superconducting machines (HTSM) for wind power systems was carried out using specially developed design program. Outline of the design program was shown and the influence of machine parameters such as pole number, rotor outer diameter and synchronous reactance on the machine performance was clarified. Three kinds of generator structure are considered for wind power systems and the HTSM operated under highly magnetic saturated conditions with conventional rotor and stator has better performance than the other types of HTSM. Furthermore, conceptual structure of 8 MW, 20 pole HTSM adopting salient-pole rotor as in the case of water turbine generators and race-truck shaped HTS field windings like Japanese Maglev was shown.

  9. A study of the financial viability of grid-connected wind turbines for farmers

    International Nuclear Information System (INIS)

    Hunter, A.G.M.; Graham, R.; Morgan, O.W.

    1997-01-01

    There is a large niche market for wind turbines on farms in the UK but firm data on financial viability in today's restricted market for electricity, and in the liberalised market after 1998, are lacking. There are many farms where high wind speed, or high electricity demand, or a combination of both, will make effective generating costs low. A methodology using the SAC systems model has now been established to study individual cases in a large sample of farms, and to examine the cumulative outcome across a geographic region. It appears that a viable generating cost of under 1.5 p/kWh would apply to some thousand farms in Scotland, potentially adding 50% to the contracted wind generating capacity of SRO-1. The systems model provides a decision support tool to inform government policy in two important areas, renewable energy and rural development. (Author)

  10. A 200-kW wind turbine generator conceptual design study

    Science.gov (United States)

    1979-01-01

    A conceptual design study was conducted to define a 200 kW wind turbine power system configuration for remote applications. The goal was to attain an energy cost of 1 to 2 cents per kilowatt-hour at a 14-mph site (mean average wind velocity at an altitude of 30 ft.) The costs of the Clayton, New Mexico, Mod-OA (200-kW) were used to identify the components, subsystems, and other factors that were high in cost and thus candidates for cost reduction. Efforts devoted to developing component and subsystem concepts and ideas resulted in a machine concept that is considerably simpler, lighter in weight, and lower in cost than the present Mod-OA wind turbines. In this report are described the various innovations that contributed to the lower cost and lighter weight design as well as the method used to calculate the cost of energy.

  11. Design study of high-temperature superconducting generators for wind power systems

    International Nuclear Information System (INIS)

    Maki, N

    2008-01-01

    Design study on high-temperature superconducting machines (HTSM) for wind power systems was carried out using specially developed design program. Outline of the design program was shown and the influence of machine parameters such as pole number, rotor outer diameter and synchronous reactance on the machine performance was clarified. Three kinds of generator structure are considered for wind power systems and the HTSM operated under highly magnetic saturated conditions with conventional rotor and stator has better performance than the other types of HTSM. Furthermore, conceptual structure of 8 MW, 20 pole HTSM adopting salient-pole rotor as in the case of water turbine generators and race-truck shaped HTS field windings like Japanese Maglev was shown

  12. Local acceptance of wind energy: Factors of success identified in French and German case studies

    International Nuclear Information System (INIS)

    Jobert, Arthur; Laborgne, Pia; Mimler, Solveig

    2007-01-01

    The objective of this paper is to identify and analyse factors that are important for winning acceptance of wind-energy parks on the local level. The developers of wind-energy parks need to know how to manage 'social acceptance' at the different stages of planning, realisation and operation. Five case studies in France and Germany focused on factors of success in developing a wind-energy project on a given site and illuminated how policy frameworks influence local acceptance. Our hypothesis is that these factors fall into two categories: institutional conditions, such as economic incentives and regulations; and site-specific conditions (territorial factors), such as the local economy, the local geography, local actors, and the actual on-site planning process (project management)

  13. Wind‐gust parametrizations at heights relevant for wind energy: a study based on mast observations

    DEFF Research Database (Denmark)

    Suomi, I.; Vihma, T.; Gryning, Sven-Erik

    2013-01-01

    Wind gusts are traditionally observed and reported at the reference height of 10 m and most gust parametrization methods have been developed only for this height. In many practical applications, e.g. in wind energy, the relevant heights are, however, up to a few hundred metres. In this study, mean...... speed, which is parametrized on the basis of the surface friction velocity, the Obukhov length and height and the boundary‐layer height. The new gust parametrization method outperformed the two older methods: the effects of surface roughness, stability and the height above the surface were well...

  14. Sensitivity study of the Continuous Release Dispersion Model (CRDM) for radioactive pollutants

    International Nuclear Information System (INIS)

    Camacho, F.

    1987-08-01

    The Continuous Release Dispersion Model (CRDM) is used to calculate spatial distribution of pollutants and their radiation doses in the event of accidental releases of radioactive material from Nuclear Generation Stations. A sensitivity analysis of the CRDM was carried out to develop a method for quantifying the expected output uncertainty due to inaccuracies and uncertainties in the input values. A simulation approach was used to explore the behaviour of the sensitivity functions. It was found that the most sensitive variable is wind speed, the least sensitive is the ambient temperature, and that largest values of normalized concentrations are likely to occur for small values of wind speed and highly stable atmospheric conditions. It was also shown that an error between 10% and 25% should be expected in the output values for a 1% overall error in the input values, and this factor could be much larger in certain situations

  15. Sensitivity study of the monogroove with screen heat pipe design

    Science.gov (United States)

    Evans, Austin L.; Joyce, Martin

    1988-01-01

    The present sensitivity study of design variable effects on the performance of a monogroove-with-screen heat pipe obtains performance curves for maximum heat-transfer rates vs. operating temperatures by means of a computer code; performance projections for both 1-g and zero-g conditions are obtainable. The variables in question were liquid and vapor channel design, wall groove design, and the number of feed lines in the evaporator and condenser. The effect on performance of three different working fluids, namely ammonia, methanol, and water, were also determined. Greatest sensitivity was to changes in liquid and vapor channel diameters.

  16. Sensitivity study of reduced models of the activated sludge process ...

    African Journals Online (AJOL)

    2009-08-07

    Aug 7, 2009 ... Sensitivity study of reduced models of the activated sludge process, for the purposes of parameter estimation and process optimisation: Benchmark process with ASM1 and UCT reduced biological models. S du Plessis and R Tzoneva*. Department of Electrical Engineering, Cape Peninsula University of ...

  17. Design tradeoff studies and sensitivity analysis. Appendix B

    Energy Technology Data Exchange (ETDEWEB)

    1979-05-25

    The results of the design trade-off studies and the sensitivity analysis of Phase I of the Near Term Hybrid Vehicle (NTHV) Program are presented. The effects of variations in the design of the vehicle body, propulsion systems, and other components on vehicle power, weight, cost, and fuel economy and an optimized hybrid vehicle design are discussed. (LCL)

  18. Short-Term Wind Speed Hybrid Forecasting Model Based on Bias Correcting Study and Its Application

    OpenAIRE

    Mingfei Niu; Shaolong Sun; Jie Wu; Yuanlei Zhang

    2015-01-01

    The accuracy of wind speed forecasting is becoming increasingly important to improve and optimize renewable wind power generation. In particular, reliable short-term wind speed forecasting can enable model predictive control of wind turbines and real-time optimization of wind farm operation. However, due to the strong stochastic nature and dynamic uncertainty of wind speed, the forecasting of wind speed data using different patterns is difficult. This paper proposes a novel combination bias c...

  19. A WRF sensitivity study for summer ozone and winter PM events in California

    Science.gov (United States)

    Zhao, Z.; Chen, J.; Mahmud, A.; Di, P.; Avise, J.; DaMassa, J.; Kaduwela, A. P.

    2014-12-01

    Elevated summer ozone and winter PM frequently occur in the San Joaquin Valley (SJV) and the South Coast Air Basin (SCAB) in California. Meteorological conditions, such as wind, temperature and planetary boundary layer height (PBLH) play crucial roles in these air pollution events. Therefore, accurate representation of these fields from a meteorological model is necessary to successfully reproduce these air pollution events in subsequent air quality model simulations. California's complex terrain and land-sea interface can make it challenging for meteorological models to replicate the atmospheric conditions over the SJV and SCAB during extreme pollution events. In this study, the performance of the Weather Research and Forecasting Model (WRF) over these two regions for a summer month (July 2012) and a winter month (January 2013) is evaluated with different model configurations and forcing. Different land surface schemes (Pleim-Xiu vs. hybrid scheme), the application of observational and soil nudging, two SST datasets (the Global Ocean Data Assimilation Experiment (GODAE) SST vs. the default SST from North American Regional Reanalysis (NARR) reanalysis), and two land use datasets (the National Land Cover Data (NLCD) 2006 40-category vs. USGS 24-category land use data) have been tested. Model evaluation will focus on both surface and vertical profiles for wind, temperature, relative humidity, as well as PBLH. Sensitivity of the Community Multi-scale Air Quality Model (CMAQ) results to different WRF configurations will also be presented and discussed.

  20. Highly reliable wind-rolling triboelectric nanogenerator operating in a wide wind speed range

    Science.gov (United States)

    Yong, Hyungseok; Chung, Jihoon; Choi, Dukhyun; Jung, Daewoong; Cho, Minhaeng; Lee, Sangmin

    2016-01-01

    Triboelectric nanogenerators are aspiring energy harvesting methods that generate electricity from the triboelectric effect and electrostatic induction. This study demonstrates the harvesting of wind energy by a wind-rolling triboelectric nanogenerator (WR-TENG). The WR-TENG generates electricity from wind as a lightweight dielectric sphere rotates along the vortex whistle substrate. Increasing the kinetic energy of a dielectric converted from the wind energy is a key factor in fabricating an efficient WR-TENG. Computation fluid dynamics (CFD) analysis is introduced to estimate the precise movements of wind flow and to create a vortex flow by adjusting the parameters of the vortex whistle shape to optimize the design parameters to increase the kinetic energy conversion rate. WR-TENG can be utilized as both a self-powered wind velocity sensor and a wind energy harvester. A single unit of WR-TENG produces open-circuit voltage of 11.2 V and closed-circuit current of 1.86 μA. Additionally, findings reveal that the electrical power is enhanced through multiple electrode patterns in a single device and by increasing the number of dielectric spheres inside WR-TENG. The wind-rolling TENG is a novel approach for a sustainable wind-driven TENG that is sensitive and reliable to wind flows to harvest wasted wind energy in the near future. PMID:27653976

  1. Healthy offshore workforce? A qualitative study on offshore wind employees' occupational strain, health, and coping.

    Science.gov (United States)

    Mette, Janika; Velasco Garrido, Marcial; Harth, Volker; Preisser, Alexandra M; Mache, Stefanie

    2018-01-23

    Offshore work has been described as demanding and stressful. Despite this, evidence regarding the occupational strain, health, and coping behaviors of workers in the growing offshore wind industry in Germany is still limited. The purpose of our study was to explore offshore wind employees' perceptions of occupational strain and health, and to investigate their strategies for dealing with the demands of offshore work. We conducted 21 semi-structured telephone interviews with employees in the German offshore wind industry. The interviews were transcribed and analyzed in a deductive-inductive approach following Mayring's qualitative content analysis. Workers generally reported good mental and physical health. However, they also stated perceptions of stress at work, fatigue, difficulties detaching from work, and sleeping problems, all to varying extents. In addition, physical health impairment in relation to offshore work, e.g. musculoskeletal and gastrointestinal complaints, was documented. Employees described different strategies for coping with their job demands. The strategies comprised of both problem and emotion-focused approaches, and were classified as either work-related, health-related, or related to seeking social support. Our study is the first to investigate the occupational strain, health, and coping of workers in the expanding German offshore wind industry. The results offer new insights that can be utilized for future research in this field. In terms of practical implications, the findings suggest that measures should be carried out aimed at reducing occupational strain and health impairment among offshore wind workers. In addition, interventions should be initiated that foster offshore wind workers' health and empower them to further expand on effective coping strategies at their workplace.

  2. Sensitivity studies on TIME2 Version 1.0

    International Nuclear Information System (INIS)

    1988-03-01

    The results of a sensitivity analysis of Version 1.0 of the TIME2 computer code to certain aspects of the input data set are presented. Parameters evaluated were: river dimensions, the density and grain size of sediment carried by the river, human intrusion data, sea level rise rate, erosion factors and meander modelling data. The sensitivity of the code to variation of single value parameters was evaluated by means of graphical comparisons. For parameters specified as probability density functions (pdf's), the Kolmogorov-Smirnov test was used. The study assists in the specification of data for TIME2 by identifying parameters to which the models used are particularly sensitive and also suggests that some input currently specified as pdf's could be replaced with single values without affecting the quality of the results obtained. (author)

  3. Linear Array Ultrasonic Transducers: Sensitivity and Resolution Study

    International Nuclear Information System (INIS)

    Kramb, V.A.

    2005-01-01

    The University of Dayton Research Institute (UDRI) under contract by the US Air Force has designed and integrated a fully automated inspection system for the inspection of turbine engines that incorporates linear phased array ultrasonic transducers. Phased array transducers have been successfully implemented into weld and turbine blade root inspections where the defect types are well known and characterized. Embedded defects in aerospace turbine engine components are less well defined, however. In order to determine the applicability of linear arrays to aerospace inspections the sensitivity of array transducers to embedded defects in engine materials must be characterized. In addition, the implementation of array transducers into legacy inspection procedures must take into account any differences in sensitivity between the array transducer and that of the single element transducer currently used. This paper discusses preliminary results in a study that compares the sensitivity of linear array and conventional single element transducers to synthetic hard alpha defects in a titanium alloy

  4. Wind turbine wake interactions at field scale: An LES study of the SWiFT facility

    International Nuclear Information System (INIS)

    Yang, Xiaolei; Boomsma, Aaron; Sotiropoulos, Fotis; Barone, Matthew

    2014-01-01

    The University of Minnesota Virtual Wind Simulator (VWiS) code is employed to simulate turbine/atmosphere interactions in the Scaled Wind Farm Technology (SWiFT) facility developed by Sandia National Laboratories in Lubbock, TX, USA. The facility presently consists of three turbines and the simulations consider the case of wind blowing from South such that two turbines are in the free stream and the third turbine in the direct wake of one upstream turbine with separation of 5 rotor diameters. Large-eddy simulation (LES) on two successively finer grids is carried out to examine the sensitivity of the computed solutions to grid refinement. It is found that the details of the break-up of the tip vortices into small-scale turbulence structures can only be resolved on the finer grid. It is also shown that the power coefficient C P of the downwind turbine predicted on the coarse grid is somewhat higher than that obtained on the fine mesh. On the other hand, the rms (root-mean-square) of the C P fluctuations are nearly the same on both grids, although more small-scale turbulence structures are resolved upwind of the downwind turbine on the finer grid

  5. Using Deep Learning to Predict Complex Systems: A Case Study in Wind Farm Generation

    Directory of Open Access Journals (Sweden)

    J. M. Torres

    2018-01-01

    Full Text Available Making every component of an electrical system work in unison is being made more challenging by the increasing number of renewable energies used, the electrical output of which is difficult to determine beforehand. In Spain, the daily electricity market opens with a 12-hour lead time, where the supply and demand expected for the following 24 hours are presented. When estimating the generation, energy sources like nuclear are highly stable, while peaking power plants can be run as necessary. Renewable energies, however, which should eventually replace peakers insofar as possible, are reliant on meteorological conditions. In this paper we propose using different deep-learning techniques and architectures to solve the problem of predicting wind generation in order to participate in the daily market, by making predictions 12 and 36 hours in advance. We develop and compare various estimators based on feedforward, convolutional, and recurrent neural networks. These estimators were trained and validated with data from a wind farm located on the island of Tenerife. We show that the best candidates for each type are more precise than the reference estimator and the polynomial regression currently used at the wind farm. We also conduct a sensitivity analysis to determine which estimator type is most robust to perturbations. An analysis of our findings shows that the most accurate and robust estimators are those based on feedforward neural networks with a SELU activation function and convolutional neural networks.

  6. A case study for evaluating potential soil sensitivity in aridland systems.

    Science.gov (United States)

    Peterman, Wendy L; Ferschweiler, Ken

    2016-04-01

    Globally, ecosystems are subjected to prolonged droughts and extreme heat events, leading to forest die-offs and dominance shifts in vegetation. Some scientists and managers view soil as the main resource to be considered in monitoring ecosystem responses to aridification. As the medium through which precipitation is received, stored, and redistributed for plant use, soil is an important factor in the sensitivity of ecosystems to a drying climate. This study presents a novel approach to evaluating where on a landscape soils may be most sensitive to drying, making them less resilient to disturbance, and where potential future vegetation changes could lead to such disturbance. The drying and devegetation of arid lands can increase wind erosion, contributing to aerosol and dust emissions. This has implications for air quality, human health, and water resources. This approach combines soil data with vegetation simulations, projecting future vegetation change, to create maps of potential areas of concern for soil sensitivity and dust production in a drying climate. Consistent with recent observations, the projections show shifts from grasslands and woodlands to shrublands in much of the southwestern region. An increase in forested area occurs, but shifts in the dominant types and spatial distribution of the forests also are seen. A net increase in desert ecosystems in the region and some changes in alpine and tundra ecosystems are seen. Approximately 124,000 km(2) of soils flagged as "sensitive" are projected to have vegetation change between 2041 and 2050, and 82,927 km(2) of soils may become sensitive because of future vegetation changes. These maps give managers a way to visualize and identify where soils and vegetation should be investigated and monitored for degradation in a drying climate, so restoration and mitigation strategies can be focused in these areas. © 2015 SETAC.

  7. Wind energy in industrial areas optional, but not obvious. A study on the chances and constraints for the use of wind energy in industrial parks

    International Nuclear Information System (INIS)

    Schoolderman, J.A.; Verbeet, E.; Jochems, A.; Versteeg, K.

    2000-06-01

    The feasibility of installing wind turbines in industrial parks in the Netherlands has been investigated. An overview is given of possibilities and constraints to fit in wind turbines in industrial areas, based on the results of a literature study, a market consultation of sectoral organizations, representatives of local industrial circles and industrial experts in the field of renewable energy. Also a telephone survey was carried out among 130 entrepreneurs in the Netherlands to determine their attitudes towards the use of sustainable energy and wind energy in industrial parks. The results of the attitude study are published in a separate report for which a separate abstract has been prepared. The intermediate results were discussed at a meeting (23 February 2000), in which representatives from the industry, provinces, municipalities and the government participated

  8. Preliminary manual of the wind farms impacts study; Manuel preliminaire de l'etude d'impact des parcs eoliens

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-11-01

    This document aims to present and propose tools and methods allowing the improve the environmental quality of the future wind farms projects. After a presentation of general notions on the wind farms and the economy of the wind energy, it presents the regulation and the procedures concerning the environmental impact. It proposes then the main possible effects and the impacts study themes. (A.L.B.)

  9. Wind erosion on Deliblato (the largest European continental sandy terrain) studied using 210Pbex and 137Cs measurements

    International Nuclear Information System (INIS)

    Krmar, M.; Hansman, J.; Todorovic, N.; Mihailovic, A.; Vucinic-Vasic, M.; Savic, R.

    2015-01-01

    The objective of this paper is to estimate the difference in wind erosion between two extreme situations: sandy soil permanently covered by grass and the nearby frequently ploughed area highly susceptible to wind erosion. The spatial pattern of soil erosion rate was investigated using 137 Cs and 210 Pb ex tracing technique. The spatial pattern of erosion rate obtained within the studied area reveal influence of topography as well as direction of prevailing winds on mobilization and transport of the soil particles. (author)

  10. 2D study of wind forces around multiple cooling towers using ...

    African Journals Online (AJOL)

    A comprehensive numerical study for the determination of wind pressure coefficients on multiple cooling towers by simulating turbulence using Reynolds Averaged Navier-Stokes Equations (RANS) models of Computational Fluid Dynamics techniques (CFD) such as, Standard k −ε , RNG k −ε , Realizable k −ε and Reynolds ...

  11. Study of wind forces on low-rise hip-roof building | Jameel ...

    African Journals Online (AJOL)

    A comprehensive numerical study of wind effects using Computational Fluid Dynamics (CFD) techniques on the low-rise hipped roof building is presented in this paper. Two Reynolds Averaged Navier–Stokes Equations (RANS) techniques such as the Standard k -e turbulence model and the Renormalization group (RNG) k ...

  12. Standard metrics and methods for conducting Avian/wind energy interaction studies

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, R.L. [California Energy Commission, Sacramento, CA (United States); Davis, H. [National Renewable Energy Lab., Golden, CO (United States); Kendall, W. [National Biological Service, Laurel, MD (United States)] [and others

    1997-12-31

    The awareness of the problem of avian fatalities at large scale wind energy developments first emerged in the late 1980`s at the Altamont Pass Wind Resource Area (WRA) in Central California. Observations of dead raptors at the Altamont Pass WRA triggered concern on the part of regulatory agencies, environmental/conservation groups, resource agencies, and wind and electric utility industries. This led the California Energy Commission staff, along with the planning departments of Alameda, Contra Costa, and Solano counties, to commission a study of bird mortality at the Altamont Pass WRA. In addition to the Altamont Pass WRA, other studies and observations have established that windplants kill birds. Depending upon the specific factors, this may or may not be a serious problem. The current level of scrutiny and caution exhibited during the permitting of a new windplant development in the United States results in costly delays and studies. This is occurring during a highly competitive period for electrical production companies in the USA. Clarification of the bird fatality issue is needed to bring it into perspective. This means standardizing metrics, defining terms, and recommending methods to be used in addressing or studying wind energy/bird interactions.

  13. Do regional weather models contribute to better wind power forecasts? A few Norwegian case studies

    DEFF Research Database (Denmark)

    Bremnes, John Bjørnar; Giebel, Gregor

    2017-01-01

    resolution of this grid determines how accurate meteorological processes can be modeled and thereby also limits forecast quality. In this study, two global and four regional operational NWP models with spatial horizontal resolutions ranging from 1 to 32 km were applied to make wind power forecasts up to 66...

  14. An Experimental Study on the Wind-Induced Response of Variable Message Signs

    Directory of Open Access Journals (Sweden)

    Debbie Meyer

    2017-11-01

    Full Text Available Variable message sign (VMS systems are widely used in motorways to provide traffic information to motorists. Such systems are subjected to wind-induced structural vibration that can lead to damage due to fatigue. The limited information that is available on the safe wind design of VMS motivated a large scale testing that was conducted at the wall of wind (WOW Experimental Facility at Florida International University (FIU. One of the objectives of the present study was to experimentally assess the wind-induced force coefficients on VMS of different geometries and utilize these results to provide improved design guidelines. A comprehensive range of VMS geometries was tested, and mean normal and lateral force coefficients, in addition to the twisting moment coefficient and eccentricity ratio, were determined using the measured data for each model, for wind directions of 0° and 45°. The results confirmed that the mean drag coefficient on a prismatic VMS is smaller than the value of 1.7 suggested by American Association of State Highway and Transportation Officials (AASHTO. An alternative to this value is presented in the form of a design matrix with coefficients ranging from 0.98 to 1.28, depending on the aspect and depth ratio of the VMS. Furthermore, results indicated that the corner modification on a VMS with chamfered edges demonstrated a reduction in the drag coefficient compared to sharper edges. Finally, the dynamic loading effects were considered by evaluating the gust effect factor, using the ASCE 7 formulations, for various VMS weights and geometries. The findings revealed a wide range of possible gust effect factors, both above and below the current AASHTO specification of 1.14. Future research may include different geometries of VMS and a wider range of wind directions.

  15. A statistical study on the correlations between plasma sheet and solar wind based on DSP explorations

    Directory of Open Access Journals (Sweden)

    G. Q. Yan

    2005-11-01

    Full Text Available By using the data of two spacecraft, TC-1 and ACE (Advanced Composition Explorer, a statistical study on the correlations between plasma sheet and solar wind has been carried out. The results obtained show that the plasma sheet at geocentric distances of about 9~13.4 Re has an apparent driving relationship with the solar wind. It is found that (1 there is a positive correlation between the duskward component of the interplanetary magnetic field (IMF and the duskward component of the geomagnetic field in the plasma sheet, with a proportionality constant of about 1.09. It indicates that the duskward component of the IMF can effectively penetrate into the near-Earth plasma sheet, and can be amplified by sunward convection in the corresponding region at geocentric distances of about 9~13.4 Re; (2 the increase in the density or the dynamic pressure of the solar wind will generally lead to the increase in the density of the plasma sheet; (3 the ion thermal pressure in the near-Earth plasma sheet is significantly controlled by the dynamic pressure of solar wind; (4 under the northward IMF condition, the ion temperature and ion thermal pressure in the plasma sheet decrease as the solar wind speed increases. This feature indicates that plasmas in the near-Earth plasma sheet can come from the magnetosheath through the LLBL. Northward IMF is one important condition for the transport of the cold plasmas of the magnetosheath into the plasma sheet through the LLBL, and fast solar wind will enhance such a transport process.

  16. A dynamic processes study of PM retention by trees under different wind conditions.

    Science.gov (United States)

    Xie, Changkun; Kan, Liyan; Guo, Jiankang; Jin, Sijia; Li, Zhigang; Chen, Dan; Li, Xin; Che, Shengquan

    2018-02-01

    Particulate matter (PM) is one of the most serious environmental problems, exacerbating respiratory and vascular illnesses. Plants have the ability to reduce non-point source PM pollution through retention on leaves and branches. Studies of the dynamic processes of PM retention by plants and the mechanisms influencing this process will help to improve the efficiency of urban greening for PM reduction. We examined dynamic processes of PM retention and the major factors influencing PM retention by six trees with different branch structure characteristics in wind tunnel experiments at three different wind speeds. The results showed that the changes of PM numbers retained by plant leaves over time were complex dynamic processes for which maximum values could exceed minimum values by over 10 times. The average value of PM measured in multiple periods and situations can be considered a reliable indicator of the ability of the plant to retain PM. The dynamic processes were similar for PM 10 and PM 2.5 . They could be clustered into three groups simulated by continually-rising, inverse U-shaped, and U-shaped polynomial functions, respectively. The processes were the synthetic effect of characteristics such as species, wind speed, period of exposure and their interactions. Continually-rising functions always explained PM retention in species with extremely complex branch structure. Inverse U-shaped processes explained PM retention in species with relatively simple branch structure and gentle wind. The U-shaped processes mainly explained PM retention at high wind speeds and in species with a relatively simple crown. These results indicate that using plants with complex crowns in urban greening and decreasing wind speed in plant communities increases the chance of continually-rising or inverse U-shaped relationships, which have a positive effect in reducing PM pollution. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. Wind farm layout optimization in complex terrain: A preliminary study on a Gaussian hill

    International Nuclear Information System (INIS)

    Feng, J; Shen, W Z

    2014-01-01

    One of the crucial problems for wind farm (WF) development is wind farm layout optimization. It seeks to find the optimal positions of wind turbines (WTs) inside a WF, so as to maximize and/or minimize a single objective or multiple objectives, while satisfying certain constraints. Although this problem for WFs in flat terrain or offshore has been investigated in many studies, it is still a challenging problem for WFs in complex terrain. In this preliminary study, the wind flow conditions of complex terrain without WTs are first obtained from computational fluid dynamics (CFD) simulation, then an adapted Jensen wake model is developed by considering the terrain features and taking the inflow conditions as input. Using this combined method, the wake effects of WF in complex terrain are properly modelled. Besides, a random search (RS) algorithm proposed in previous study is improved by adding some adaptive mechanisms and applied to solve the layout optimization problem of a WF on a Gaussian shape hill. The layout of the WF with a certain number of WTs is optimized to maximize the total power output, which obtained steady improvements over expert guess layouts

  18. Radiation sensitization studies by silymarin on HCT-15 cells

    International Nuclear Information System (INIS)

    Lal, Mitu; Gupta, Damodar; Arora, R.

    2014-01-01

    Radiotherapy has been widely used for treatment of human cancers. However, cancer cells develop radioresistant phenotypes following multiple exposures to the treatment agent that decrease the efficacy of radiotherapy. Here it was investigated that the radiation sensitization effects of silymarin found in colon cancer. The aim of this study was to investigate mechanisms involved in radiation sensitization growth inhibitory effect of silymarin in combination with radiation, in Human colon carcinoma (HCT-15). The human colon carcinoma was utilized and SRB-assay was performed to study anti-proliferative effect of silymarin in combination with gamma radiation (2 Gy) appropriate radiation dose was optimized and confirmed by clonogenic assay. Microscopic analysis was done by staining with Hoechst-33342, DAPI, Propidium iodide to confirm the presence of apoptosis. Nitric oxide production, changes in lipid peroxidation, Cell cycle analysis were carried out and mitochondrial membrane potential was measured by uptake of cationic dye JC-1 by using flow cytometer. Silymarin in combination with radiation (2 Gy) inhibited 70% ± 5% population growth of HCT-15 cells in time and dose dependent manner. Pre treatment of cells with silymarin for 30 min before radiation was found to be most effective for radiation sensitization. There was 25% increase in levels of nitric oxide as compare to control, whereas 2.5 fold change in lipid peroxidation with respect to control. IR-induced apoptosis in HCT-15 cell line was significantly enhanced by silymarin, as reflected by viability, DNA fragmentation, and mitochondrial dysfunction. Additionally, silymarin in combination with IR is found to be effective in sensitization of HCT-15 cells. In vivo studies on development of tumor and sensitization aspects needs to done in future. (author)

  19. Noise annoyances from wind power: Survey of the population living close to a wind power plant. Final report: Part 3 Main study

    International Nuclear Information System (INIS)

    Pedersen, Eja; Persson-Waye, K.

    2002-02-01

    To evaluate the occurrence of annoyance from wind turbines, a study was performed in Laholm in May 2000. The aim was to obtain dose response relationships between calculated sound levels and noise annoyance and appropriate sound description as well as analysing the influence of other variables on noise annoyance. A questionnaire survey was performed in 6 areas comprising 16 wind turbines, of which 14 had an effect of 600 kW. The purpose of the study was masked. Among questions on living conditions in the countryside, questions directly related to wind turbines were included. The study population (n=518) comprised one randomly selected subject between the ages of 18 to 75 years in each household living within a calculated wind turbine sound level of 25 to 40 dBA. The response rate was 68.7% (n=356). Calculated distributions of A-weighted sound level were performed for each area and plotted on geographical maps in 2.5 dBA steps. Each dwelling could thus be given a sound level within an interval of 2.5 dBA. The most frequently occurring source of noise annoyance was noise from rotor blades. The proportions of respondents annoyed by noise increased with calculated sound level. Among respondents exposed to sound levels of 35.0-37.5 dBA, 43% responded themselves to be rather or much annoyed. A-weighted sound level was only one variable explaining annoyance. Annoyance was correlated to a larger extent by the intrusiveness of the sound character swishing. Noise annoyance was interrelated to the respondents' opinion of the visual impact of wind turbines, while attitude towards wind power in general had no greater influence. Disturbance of spoilt view was reported to a similar degree as noise disturbance. Further investigations are needed to clarify factors of importance for the disturbance of view. All the wind turbines in the study had constant rotation speed. The greater wind turbines that are now erected often have variable speed, which may lead to a sound comprising

  20. Role of Surface Energy Exchange for Simulating Wind Turbine Inflow: A Case Study in the Southern Great Plains, USA

    Directory of Open Access Journals (Sweden)

    Sonia Wharton

    2014-12-01

    Full Text Available The Weather Research and Forecasting (WRF model is used to investigate choice of land surface model (LSM on the near surface wind profile, including heights reached by multi-megawatt (MW wind turbines. Simulations of wind profiles and surface energy fluxes were made using five LSMs of varying degrees of sophistication in dealing with soil–plant–atmosphere feedbacks for the Department of Energy (DOE Southern Great Plains (SGP Atmospheric Radiation Measurement Program (ARM Central Facility in Oklahoma, USA. Surface flux and wind profile measurements were available for validation. WRF was run for three, two-week periods covering varying canopy and meteorological conditions. The LSMs predicted a wide range of energy flux and wind shear magnitudes even during the cool autumn period when we expected less variability. Simulations of energy fluxes varied in accuracy by model sophistication, whereby LSMs with very simple or no soil–plant–atmosphere feedbacks were the least accurate; however, the most complex models did not consistently produce more accurate results. Errors in wind shear were also sensitive to LSM choice and were partially related to energy flux accuracy. The variability of LSM performance was relatively high suggesting that LSM representation of energy fluxes in WRF remains a large source of model uncertainty for simulating wind turbine inflow conditions.

  1. FY 1998 Report on development of large-scale wind power generation systems. Feasibility study on development of new technologies for wind power generation, and study on local wind resource prediction model; 1998 nendo ogata furyoku hatsuden system kaihatsu seika hokokusho. Furyoku hatsuden shingijutsu kaihatsu kanosei chosa (kyokusho fukyo yosoku shuho ni kansuru chosa)

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-03-01

    Described herein are the FY 1998 results of the study on local wind resource prediction model. The local wind resource prediction models developed so far apply the solutions based on the existing linear models (WASP and AVENU) for relatively flat terrain. These models are studied for their applicability limits. The study covers wind direction and speed patterns of the surface wind and upper winds at 3 sites in Hokkaido, Fukushima Pref. and Shizuoka Pref. The surface winds are found to be correlated with the upper winds both for wind direction and wind speed in almost all cases. Next, wind resources simulations are carried out for each of the classified weather patterns using the existing models, and the prediction errors are studied. The results show that the prediction accuracy of the existing linear models is highly dependent on inputs of observed data, and that the accuracy tends to decrease for the situations where the upper and surface wind conditions greatly differ from each other, as in the case of a land and sea breeze of thermal origin. It is also confirmed that prediction accuracy is lower on complex terrain than on flat terrain. (NEDO)

  2. Wind energy

    International Nuclear Information System (INIS)

    Anon.

    1992-01-01

    This chapter discusses the role wind energy may have in the energy future of the US. The topics discussed in the chapter include historical aspects of wind energy use, the wind energy resource, wind energy technology including intermediate-size and small wind turbines and intermittency of wind power, public attitudes toward wind power, and environmental, siting and land use issues

  3. Statistical study of waves distribution in the inner magnetosphere using geomagnetic indices and solar wind parameters

    Science.gov (United States)

    Aryan, H.; Yearby, K.; Balikhin, M. A.; Krasnoselskikh, V.; Agapitov, O. V.

    2013-12-01

    The interaction of gyroresonant wave particles with chorus waves largely determine the dynamics of the Earth's radiation belts that effects the acceleration and loss of radiation belt electrons. The common approach is to present model waves distribution in the inner magnetosphere under different values of geomagnetic activity as expressed by the geomagnetic indices. However it is known that solar wind parameters such as bulk velocity (V) and density (n) are more effective in the control of high energy fluxes at the geostationary orbit. Therefore in the present study the set of parameters of the wave distribution is expanded to include the solar wind parameters in addition to the geomagnetic indices. The present study examines almost four years (01, January, 2004 to 29, September, 2007) of Cluster STAFF-SA, Double Star TC1 and OMNI data in order to present a combined model of wave magnetic field intensities for the chorus waves as a function of magnetic local time (MLT), L-shell (L*), geomagnetic activity, and solar wind velocity and density. Generally, the largest wave intensities are observed during average solar wind velocities (3006cm-3. On the other hand the wave intensity is lower and limited between 06:00 to 18:00 MLT for V700kms-1.

  4. Wave Tank Studies of Strong Modulation of Wind Ripples Due To Long Waves

    Science.gov (United States)

    Ermakov, S.; Sergievskaya, I.; Shchegolkov, Yu.

    Modulation of wind capillary-gravity ripples due to long waves has been studied in wave tank experiment at low wind speeds using Ka-band radar. The experiments were carried out both for clean water and the water surface covered with surfactant films. It is obtained that the modulation of radar signals is quite strong and can increase with surfactant concentration and fetch. It is shown that the hydrodynamic Modulation Transfer Function (MTF) calculated for free wind ripples and taking into account the kinematic (straining) effect, variations of the wind stress and variations of surfactant concentration strongly underestimates experimental MTF-values. The effect of strong modulation is assumed to be connected with nonlinear harmonics of longer dm-cm- scale waves - bound waves ("parasitic ripples"). The intensity of bound waves depends strongly on the amplitude of decimetre-scale waves, therefore even weak modulation of the dm-scale waves due to long waves results to strong ("cascade") modulation of bound waves. Modulation of the system of "free/bound waves" is estimated using results of wave tank studies of bound waves generation and is shown to be in quali- tative agreement with experiment. This work was supported by MOD, UK via DERA Winfrith (Project ISTC 1774P) and by RFBR (Project 02-05-65102).

  5. STUDY OF PATHOGENESIS AND ITS SENSITIVITY PATTERN IN UTI

    Directory of Open Access Journals (Sweden)

    Rajendra Prasad Kathula

    2016-06-01

    Full Text Available BACKGROUND Urinary tract infections are common causes of both community acquired and nosocomial infections in adult patients admitted in the hospitals. Urinary tract infections can be defined as the presence of pathogenic bacteria in significant colony count in the bladder of upper urinary tract with its associated consequences. Asymptomatic bacteriuria is a term used to designate urinary tract infections in the absence of symptoms with the growth of bacteria colonies often crossing 1,00,000/mL in a freshly voided midstream urine sample. Urethritis and cystitis are characterised by the inflammation of the urethra and bladder with symptoms of dysuria, frequency and lower pubic pain and it is associated with fever. Acute pyelonephritis is the bacterial infection of renal parenchyma and it is characterised by fever with rigors, flank pain, vomiting, costovertebral tenderness with or without symptoms of cystitis. It may be associated with pus formation. Prostatitis is quiet common and it involves infective inflammation of the prostate associated with dysuria, urgency, frequency and pain in the lower abdomen, perineum, or base of the penis. A sincere effort has been made towards this study on pathogenesis and its sensitivity pattern in UTI. METHODS One hundred cases who visited the Department of Surgery, Government Medical College, Nizamabad were used as the sample size of the study. The plethora of the signs and symptoms which were seen were noted and the mid catch of the urine was done and sent to the Department of Microbiology for the pathogens to be identified. The sensitivity pattern was also studied and reported. The study was done from October 2012 to November 2013. RESULT The most common pathogen was E. coli and the most sensitivity of the commonest pathogen (E. coli was found to be towards Nitrofurantoin. CONCLUSION In this study, the most common pathogens which causes the UTI and the sensitivity pattern has been reported. The study is

  6. Analysis of vehicle dynamics under sadden cross wind

    Science.gov (United States)

    Walczak, S.

    2016-09-01

    In this paper, the way of calculating aerodynamic forces acting on a vehicle passing in the region of sadden cross wind was presented. The CarDyn, a vehicle dynamics simulation program, developed by the author was used. The effects of the cross wind were studied with a fixed steering wheel simulation. On the base of computer simulations the car cross wind sensitivity were determined, and vehicle responses such as lateral offset, side acceleration and yaw angular velocity are presented.

  7. Studies on radiation-sensitive nonsilver halide materials, (2)

    International Nuclear Information System (INIS)

    Komizu, Hideo; Honda, Koichi; Yabe, Akira; Kawasaki, Masami; Yamanaka, Takeshi.

    1980-01-01

    Dye-precursors made from furfural and some aniline derivatives become red-colored upon irradiation with ionization radiatios in PVC matrix, forming Stenhouse salts with the HCl evolved from the matrix. The coloration of the precursor from N-methylaniline, having the most excellent potential for dosimetry among the precursors, was studied for the irradiation of electron beam (60 kV) and X-ray (50 - 240 kVp). The following conclusions were obtained for the electron beam bombardment. (1) The response range is 10 -8 - 10 -6 C/cm 2 or 10 3 - 10 5 rad, where good linearity between coloration and charge density exists. (2) The highest sensitivity is obtained when the concentration of the precursor is >=5 wt% for the amount of PVC and the film thickness is >=32 μm. (3) Addition of 25 wt% of DOP enhances not only the sensitivity by ca. 20% but also the stability of the color from several days to several months. (4) The sensitivity is increased by ca. 15% when a conductive base is used for the film. (5) G value for the formation of the dye, i.e., that for the formation of HCl is 13.5 - 15.5. The followings were obtained for the irradiation of X-ray. (1) The response range is 10 3 - 10 5 R or rad. (2) The sensitivity for the absorbed dose is independent of the energy but is approximately proportional to the film thickness. (3) The sensitivity is higher than that for electrons by the factor of ca. 1.6, reflecting the higher G(HCl) value, 23 - 25. (author)

  8. Cost-benefit analysis of remote hybrid wind-diesel power stations: Case study Aegean Sea islands

    International Nuclear Information System (INIS)

    Kaldellis, J.K.; Kavadias, K.A.

    2007-01-01

    More than one third of world population has no direct access to interconnected electrical networks. Hence, the electrification solution usually considered is based on expensive, though often unreliable, stand-alone systems, mainly small diesel-electric generators. Hybrid wind-diesel power systems are among the most interesting and environmental friendly technological alternatives for the electrification of remote consumers, presenting also increased reliability. More precisely, a hybrid wind-diesel installation, based on an appropriate combination of a small diesel-electric generator and a micro-wind converter, offsets the significant capital cost of the wind turbine and the high operational cost of the diesel-electric generator. In this context, the present study concentrates on a detailed energy production cost analysis in order to estimate the optimum configuration of a wind-diesel-battery stand-alone system used to guarantee the energy autonomy of a typical remote consumer. Accordingly, the influence of the governing parameters-such as wind potential, capital cost, oil price, battery price and first installation cost-on the corresponding electricity production cost is investigated using the developed model. Taking into account the results obtained, hybrid wind-diesel systems may be the most cost-effective electrification solution for numerous isolated consumers located in suitable (average wind speed higher than 6.0 m/s) wind potential regions

  9. A study on the possibility of cooling of schools by natural wind flow. Paper no. IGEC-1-146

    International Nuclear Information System (INIS)

    Setodemaram, K.; Golneshan, A.A.; Jafarpur, Kh.

    2005-01-01

    In this paper, the possibility of using 'wind' to cool (by wind tower) the air spaces in schools is studied. In order to study the effect of wind tower on natural cooling of schools, one has to determine the value of convective heat transfer coefficient in the classes. For this purpose, a 1:35 scale plexi glass model of a typical 8- classes school was made and a series of experiments were conducted in a wind tunnel. Mass transfer analogy using naphthalene sublimation was employed to measure the convective heat transfer coefficient in the model. It's worth mentioning that the plexi-model was equipped with a Baud-geer (wind tower) for studying of air into classes. After determining the convective heat transfer coefficient, effect of students and night ventilation on temperature variations in the classes was studied by computer simulation. (author)

  10. Identifying predictors of attitudes towards local onshore wind development with reference to an English case study

    International Nuclear Information System (INIS)

    Jones, Christopher R.; Eiser, J. Richard

    2009-01-01

    The threats posed by climate change are placing governments under increasing pressure to meet electricity demand from low-carbon sources. In many countries, including the UK, legislation is in place to ensure the continued expansion of renewable energy capacity. Onshore wind turbines are expected to play a key role in achieving these aims. However, despite high levels of public support for onshore wind development in principle, specific projects often experience local opposition. Traditionally this difference in general and specific attitudes has been attributed to NIMBYism (not in my back yard), but evidence is increasingly calling this assumption into question. This study used multiple regression analysis to identify what factors might predict attitudes towards mooted wind development in Sheffield, England. We report on the attitudes of two groups; one group (target) living close to four sites earmarked for development and an unaffected comparison group (comparison). We found little evidence of NIMBYism amongst members of the target group; instead, differences between general and specific attitudes appeared attributable to uncertainty regarding the proposals. The results are discussed with respect to literature highlighting the importance of early, continued and responsive community involvement in combating local opposition and facilitating the deployment of onshore wind turbines.

  11. Observational and numerical study of the Vardaris wind regime in northern Greece

    Science.gov (United States)

    Koletsis, I.; Giannaros, T. M.; Lagouvardos, K.; Kotroni, V.

    2016-05-01

    The Axios Valley, located in central-northern Greece, is surrounded by complex topography that plays a significant role in the modification of wind flow, both in terms of speed and direction. The characteristic wind regime of this valley is Vardaris, a northwesterly wind that prevails in this region, especially during the cold period of the year. Vardaris is well known for its consistent direction and high intensity, as well as for the effective advection of cold and dry air, often resulting to significant damages in local infrastructures and agriculture. A field campaign under the name AXIOS took place during the period from November 2007 through May 2008 in order to examine this particular wind flow. The analysis of the in situ observational data, which was funded by the research program THESPIA-KRIPIS, showed that topography plays a key role in intensifying Vardaris, generating gusts that approximated 30 m s- 1 during the experimental period. The air temperature and humidity fields were also found to be significantly influenced. In addition to the observational study, an intense Vardaris episode was simulated with the Weather Research and Forecasting (WRF) model at high horizontal resolution. Results revealed that the model was able to reproduce the favorable environmental conditions that lead to Vardaris occurrence, providing a useful insight on the physical mechanisms explaining its structure.

  12. Study of Vertical Axis Wind Turbine for Energy Harvester in A Fishing Boat

    Science.gov (United States)

    Budi, E. M.; Banjarnahor, D. A.; Hanifan, M.

    2017-07-01

    The wind speed in the southern beach of West Java Indonesia is quite promising for wind energy harvesting. A field survey reported that the wind speed reached 10 m/s, while the average recorded in a year is about 4.7 m/s. In this study, two vertical axis wind turbines (VAWT) were compared to be used in that area through calculation as well as experiments. The experiments measured that the turbines can produce about 7.82W and 2.33W of electricity respectively. These experiments are compared with theoretical calculation to obtain the performance of both turbines used. The coefficient of performance (cp) experimentally is 0.09 for Turbine 1 (hybrid Savonius-Darrieus rotor) and 0.14 for Turbine 2 (Savonius rotor). While, rotor’s mechanical performance Cpr, obtained theoritically through calculation, is 0.36 for Turbine 1 and 0.12 for Turbine 2. These results are analysed from mechanical and electrical view.

  13. Voltage control of a variable speed wind turbine connected to an isolated load: Experimental study

    International Nuclear Information System (INIS)

    Masmoudi, Abdelkarim; Krichen, Lotfi; Ouali, Abderrazak

    2012-01-01

    Highlights: ► We develop an experimental test bench of a wind energy conversion system. ► A DC motor is emulating a variable speed wind turbine using a DS1104 card. ► The production unit is supplying a three-phase load. ► A voltage control is established in order to regulate the DC bus voltage and the line-to-line voltages. - Abstract: This study is interested in the development of an experimental test bench of an autonomous wind energy conversion system (WECS) based on a permanent magnet synchronous generator (PMSG). After the description of the test bench, the elements constituting the WECS are presented. Then, a real time model implemented under a digital signal processor (DSP) system is established. The first objective of this work is to validate the functionality of the test bench leading to experiment some principles developed in theory. The second objective is to control the load connection voltages and the DC bus voltage. For the first control, two resonant controllers are used and for the second one, a dump load, connected to the DC bus, offers the possibility to maintain a balance between production and consumption in spite of wind fluctuations and load variations. The experimental results show the effectiveness of the test bench trying out in real time the behavior of a WECS supplying an isolated load.

  14. Observations and numerical studies of gamma-ray emission in colliding-wind binaries

    International Nuclear Information System (INIS)

    Reitberger, K.

    2014-01-01

    Massive stars in binary systems have long been regarded as potential sources of high-energy gamma rays. The emission is thought to arise in the region where the stellar winds collide, thereby producing accelerated particles which subsequently emit gamma rays.This scenario is supported by observations with the Fermi Large Area Telescope presented in this thesis. To address the underlying emission mechanisms in a quantitative way, numerical simulations that incorporate hydrodynamics, the acceleration of charged particles as well as the subsequent gamma-ray emission were found to be needed.This thesis presents the analysis of a high-energy gamma-ray source and its identification with the particle-accelerating colliding-wind binary system Eta Carinae. In order to go beyond the present understanding of such objects, this work provides detailed description of a new 3D-hydrodynamical model, which incorporates the line-driven acceleration of the winds, gravity, orbital motion and the radiative cooling of the shocked plasma, as well as the diffusive shock acceleration of charged particles in the wind collision region. In a subsequent step we simulate and study the resulting gamma-ray emission via relativistic bremsstrahlung, anisotropic inverse Compton radiation and neutral pion decay. (author) [de

  15. Investigation of the potential of wind energy applications in the Sct. Petersburg region. Pre-feasibility study report. Phase 1

    International Nuclear Information System (INIS)

    1995-11-01

    It was proposed to initiate an investigation and, if found to be viable, a feasibility study of the possibilities for partly substituting and supplementing the existing nuclear and fossil fuel based energy supply of the St. Petersburg region with environmentally benign wind energy. The feasibility study is expected to lead to one or more pilot projects. The proposal outlines a three-phased project including an investigation, a feasibility study and a full scale demonstration of wind energy in this region. A 4th phase is envisaged, and this will include the large scale introduction of wind energy applications using national and international financing and resulting in increased local production. The report covers the first phase, the investigation which includes data acquisition and desk studies. It is shown that technically exploitable wind potential exists in the St. Petersburg region, that local production of wind turbine equipment will reduce wind turbine costs due to decreased transport costs and lower local salaries, that suitable sites for the demonstration of both grid-connected wind farms and wind-diesel systems have been preliminarily identified and that the demonstration plants investigated have exhibited reasonable economic parameters - IRR in the range of 9 - 15%. But a feasibility study phase (2) including engineering and economic analyses must be carried out in order to reach the necessary detailed understanding of the technical and economic implications of full scale demonstration projects. (EG)

  16. The role of wind in hydrochorous mangrove propagule dispersal

    NARCIS (Netherlands)

    Van der Stocken, T.; De Ryck, D.J.R.; Balke, T.; Bouma, T.J.; Dahdouh-Guebas, F.; Koedam, N.

    2013-01-01

    Although wind has been recognized to be an important factor in the dispersal of hydrochorous mangrove propagules, and hence in the quantification of (meta)population dynamics, the species-specific sensitivity to wind effects has not been studied. We combined observations from a controlled experiment

  17. Stochastic dynamic stiffness of surface footing for offshore wind turbines

    DEFF Research Database (Denmark)

    Vahdatirad, Mohammadjavad; Andersen, Lars Vabbersgaard; Ibsen, Lars Bo

    2014-01-01

    Highlights •This study concerns the stochastic dynamic stiffness of foundations for large offshore wind turbines. •A simple model of wind turbine structure with equivalent coupled springs at the base is utilized. •The level of uncertainties is quantified through a sensitivity analysis. •Estimation...

  18. Washing with the Wind: A Study of Scripting towards Sustainability

    DEFF Research Database (Denmark)

    Jensen, Rikke Hagensby; Raptis, Dimitrios; Kjeldskov, Jesper

    2018-01-01

    Within sustainable HCI research, we have witnessed a growing interest in studying interaction designs that support households to ‘shift’ energy usage to times when it is sustainably favourable. In this paper, we investigate shifting through a purposely provocative and scripted design, which chall...

  19. Numerical study of Wavy Blade Section for Wind Turbines

    DEFF Research Database (Denmark)

    Kobæk, C. M.; Hansen, Martin Otto Laver

    2016-01-01

    than a flipper having a smooth trailing edge and thus could be potentially beneficial when catching food. A thorough literature study of the Wavy Blade concept is made and followed by CFD computations of two wavy blade geometries and a comparison with their baseline S809 airfoil at conditions more...

  20. A review of recent studies on the mechanisms and analysis methods of sub-synchronous oscillation in wind farms

    Science.gov (United States)

    Wang, Chenggen; Zhou, Qian; Gao, Shuning; Luo, Jia; Diao, Junchao; Zhao, Haoran; Bu, Jing

    2018-04-01

    This paper reviews the recent studies of Sub-Synchronous Oscillation(SSO) in wind farms. Mechanisms and analysis methods are the main concerns of this article. A classification method including new types of oscillation occurred between wind farms and HVDC systems and oscillation caused by Permanent Magnet Synchronous Generators(PMSG) is proposed. Characteristics of oscillation analysis techniques are summarized.

  1. Improved design of large wind turbine blade of fibre composites based on studies of scale effects (Phase 1). Summary report

    DEFF Research Database (Denmark)

    Sørensen, Bent F.; Jørgensen, E.; Debel, C.P.

    2004-01-01

    The main aim of the present study was to enhance the understanding of damage evolution in wind turbine blades by a combination of structural- and material modelling. Basic damage modes were identified in wind turbines tested to failure under static andcyclic loadings. Two of the observed damage...

  2. Wind Turbine Converter Control Interaction with Complex Wind Farm Systems

    DEFF Research Database (Denmark)

    Kocewiak, Lukasz Hubert; Hjerrild, Jesper; Bak, Claus Leth

    2013-01-01

    . The same wind turbine converter control strategy is evaluated in two different wind farms. It is emphasised that the grid-side converter controller should be characterised by sufficient harmonic/noise rejection and adjusted depending on wind farms to which it is connected. Various stability indices......This study presents wind turbine converter stability analysis of wind farms in frequency domain. The interaction between the wind turbine control system and the wind farm structure in wind farms is deeply investigated. Two wind farms (i.e. Horns Rev II and Karnice) are taken into consideration...... in this study. It is shown that wind farm components, such as long high-voltage alternating current cables and park transformers, can introduce significant low-frequency series resonances seen from the wind turbine terminals that can affect wind turbine control system operation and overall wind farm stability...

  3. Seismic analysis of steam generator and parameter sensitivity studies

    International Nuclear Information System (INIS)

    Qian Hao; Xu Dinggen; Yang Ren'an; Liang Xingyun

    2013-01-01

    Background: The steam generator (SG) serves as the primary means for removing the heat generated within the reactor core and is part of the reactor coolant system (RCS) pressure boundary. Purpose: Seismic analysis in required for SG, whose seismic category is Cat. I. Methods: The analysis model of SG is created with moisture separator assembly and tube bundle assembly herein. The seismic analysis is performed with RCS pipe and Reactor Pressure Vessel (RPV). Results: The seismic stress results of SG are obtained. In addition, parameter sensitivities of seismic analysis results are studied, such as the effect of another SG, support, anti-vibration bars (AVBs), and so on. Our results show that seismic results are sensitive to support and AVBs setting. Conclusions: The guidance and comments on these parameters are summarized for equipment design and analysis, which should be focused on in future new type NPP SG's research and design. (authors)

  4. WindNet: Improving the impact assessment of wind power projects

    Directory of Open Access Journals (Sweden)

    Christopher R. Jones

    2014-12-01

    Full Text Available Growing international demand for renewable energy has led to rapid growth in the wind power sector and wind farms are becoming an increasingly common feature of landscapes and seascapes in many countries. However, as the most appropriate locations within established markets are taken up, and as wind power penetrates new markets, there is an increasing likelihood that proposed projects will encroach on sensitive landscapes and residential areas. This will present challenges for the industry, particularly due to the impact that public opinion can have upon the outcomes of planning decisions about specific projects. This article introduces the four key dimensions of the WindNet programme, which are helping to elucidate some of the socio-technical debates that will likely shape the future of the wind power sector. The article outlines studies investigating (1 public responses to cumulative landscape and visual impacts, (2 the auditory impact of wind power projects on human health, (3 the science of wind farm design and its implications for planning, and (4 the relevance of the democratic deficit explanation of the so-called "social gap" in wind farm siting. The outcomes of the research being conducted by WindNet stand to help reduce uncertainty within the planning process and assist in providing a more comprehensive and fairer assessment of the possible impacts associated with wind power project development.

  5. Cost-benefit analysis of wind energy. A case study of Kayathar wind mills in Tamil Nadu

    International Nuclear Information System (INIS)

    Varadarajan, D.B.

    1995-01-01

    In recent years we have been encountering what is termed as Energy Crisis. Energy crisis is not only a threat to any economy but also posses a challenge in correcting the deficiency. India which is going in for massive industrialization is a population giant and has to reckon with the very relevant issue of energy crisis. In this regard the Indian Government has laid a great deal of emphasis on the development and harnessing of alternative sources of energy. Among the various types of renewable energy sources wind energy is present by the only proven alternative in the energy structure. Along with the evolution of man form primitive stage to the present civilisation, the wind energy has also moved with time from its ancient period to the present stage of sophistication which can be adopted to various needs like water pumping and power generation. (author)

  6. Cost-benefit analysis of wind energy. A case study of Kayathar wind mills in Tamil Nadu

    Energy Technology Data Exchange (ETDEWEB)

    Varadarajan, D B [Madurai Kamaraj Univ., Madurai (India). Dept. of Environmental Economics

    1996-12-31

    In recent years we have been encountering what is termed as Energy Crisis. Energy crisis is not only a threat to any economy but also posses a challenge in correcting the deficiency. India which is going in for massive industrialization is a population giant and has to reckon with the very relevant issue of energy crisis. In this regard the Indian Government has laid a great deal of emphasis on the development and harnessing of alternative sources of energy. Among the various types of renewable energy sources wind energy is present by the only proven alternative in the energy structure. Along with the evolution of man form primitive stage to the present civilisation, the wind energy has also moved with time from its ancient period to the present stage of sophistication which can be adopted to various needs like water pumping and power generation. (author)

  7. Cost-benefit analysis of wind energy. A case study of Kayathar wind mills in Tamil Nadu

    Energy Technology Data Exchange (ETDEWEB)

    Varadarajan, D.B. [Madurai Kamaraj Univ., Madurai (India). Dept. of Environmental Economics

    1995-12-31

    In recent years we have been encountering what is termed as Energy Crisis. Energy crisis is not only a threat to any economy but also posses a challenge in correcting the deficiency. India which is going in for massive industrialization is a population giant and has to reckon with the very relevant issue of energy crisis. In this regard the Indian Government has laid a great deal of emphasis on the development and harnessing of alternative sources of energy. Among the various types of renewable energy sources wind energy is present by the only proven alternative in the energy structure. Along with the evolution of man form primitive stage to the present civilisation, the wind energy has also moved with time from its ancient period to the present stage of sophistication which can be adopted to various needs like water pumping and power generation. (author)

  8. Modelling of pedestrian level wind environment on a high-quality mesh: A case study for the HKPolyU campus

    DEFF Research Database (Denmark)

    Du, Yaxing; Mak, Cheuk Ming; Ai, Zhengtao

    2018-01-01

    Quality and efficiency of computational fluid dynamics (CFD) simulation of pedestrian level wind environment in a complex urban area are often compromised by many influencing factors, particularly mesh quality. This paper first proposes a systematic and efficient mesh generation method and then p......Quality and efficiency of computational fluid dynamics (CFD) simulation of pedestrian level wind environment in a complex urban area are often compromised by many influencing factors, particularly mesh quality. This paper first proposes a systematic and efficient mesh generation method...... and then performs detailed sensitivity analysis of some important computational parameters. The geometrically complex Hong Kong Polytechnic University (HKPolyU) campus is taken as a case study. Based on the high-quality mesh system, the influences of three important computational parameters, namely, turbulence...... model, near-wall mesh density and computational domain size, on the CFD predicted results of pedestrian level wind environment are quantitatively evaluated. Validation of CFD models is conducted against wind tunnel experimental data, where a good agreement is achieved. It is found that the proposed mesh...

  9. Climate-sensitive urban design through Envi-Met simulation: case study in Kemayoran, Jakarta

    Science.gov (United States)

    Kusumastuty, K. D.; Poerbo, H. W.; Koerniawan, M. D.

    2018-03-01

    Indonesia as a tropical country which the character of its climate are hot and humid, the outdoor activity applications are often disrupted due to discomfort in thermal conditions. Massive construction of skyscrapers in urban areas are caused by the increase of human population leads to reduced green and infiltration areas that impact to environmental imbalances and triggering microclimate changes with rising air temperatures on the surface. The area that significantly experiences the rise of temperature in the Central Business District (CBD), which has need an analysis to create thermal comfort conditions to improve the ease of outdoor activities by an approach. This study aims to design the Kemayoran CBD through Climate Sensitive Urban Design especially in hot and humid tropical climate area and analyze thermal comfort level and optimal air conditioning in the outdoor area. This research used a quantitative method by generating the design using Climate Sensitive Urban Design principle through Envi-met 4.1 simulation program to find out the value of PMV, air temperature, wind speed and relative humidity conditions. The design area considers the configuration of buildings such as the distance between buildings, the average height, the orientation of the building, and the width of the road.

  10. Short-term nighttime wind turbine noise and cardiovascular events: A nationwide case-crossover study from Denmark.

    Science.gov (United States)

    Poulsen, Aslak Harbo; Raaschou-Nielsen, Ole; Peña, Alfredo; Hahmann, Andrea N; Nordsborg, Rikke Baastrup; Ketzel, Matthias; Brandt, Jørgen; Sørensen, Mette

    2018-05-01

    The number of people exposed to wind turbine noise (WTN) is increasing. WTN is reported as more annoying than traffic noise at similar levels. Long-term exposure to traffic noise has consistently been associated with cardiovascular disease, whereas effects of short-term exposure are much less investigated due to little day-to-day variation of e.g. road traffic noise. WTN varies considerably due to changing weather conditions allowing investigation of short-term effects of WTN on cardiovascular events. We identified all hospitalisations and deaths from stroke (16,913 cases) and myocardial infarction (MI) (17,559 cases) among Danes exposed to WTN between 1982 and 2013. We applied a time-stratified, case-crossover design. Using detailed data on wind turbine type and hourly wind data at each wind turbine, we simulated mean nighttime outdoor (10-10,000 Hz) and nighttime low frequency (LF) indoor WTN (10-160 Hz) over the 4 days preceding diagnosis and reference days. For indoor LF WTN between 10 and 15 dB(A) and above 15 dB(A), odds ratios (ORs) for MI were 1.27 (95% confidence interval (CI): 0.97-1.67; cases = 198) and 1.62 (95% CI: 0.76-3.45; cases = 21), respectively, when compared to indoor LF WTN below 5 dB(A). For stroke, corresponding ORs were 1.17 (95% CI: 0.95-1.69; cases = 166) and 2.30 (95% CI: 0.96-5.50; cases = 15). The elevated ORs above 15 dB(A) persisted across sensitivity analyses. When looking at specific lag times, noise exposure one day before MI events and three days before stroke events were associated with the highest ORs. For outdoor WTN at night, we observed both increased and decreased risk estimates. This study did not provide conclusive evidence of an association between WTN and MI or stroke. It does however suggest that indoor LF WTN at night may trigger cardiovascular events, whereas these events seemed largely unaffected by nighttime outdoor WTN. These findings need reproduction, as they were based on few cases

  11. A systematic approach of bottom-up assessment methodology for an optimal design of hybrid solar/wind energy resources – Case study at middle east region

    International Nuclear Information System (INIS)

    Ifaei, Pouya; Karbassi, Abdolreza; Jacome, Gabriel; Yoo, ChangKyoo

    2017-01-01

    Highlights: • Proposing DaSOSaCa flowchart as a novel hybrid solar/wind assessment approach. • Calculating four key parameters to generate synthetic wind hourly data for Iran. • Proposing technical and economic hybrid solar/wind GIS maps of Iran. • Revising renewable energies management plans of Iran by macroeconomic evaluation. - Abstract: In the current study, an algorithm-based data processing, sizing, optimization, sensitivity analysis and clustering approach (DaSOSaCa) is proposed as an efficient simultaneous solar/wind assessment methodology. Accordingly, data processing is performed to obtain reliable high quality meteorological data among various datasets, which are used for hybrid photovoltaic/wind turbine/storage/converter system optimal design for consequent sites in a large region. The optimal hybrid systems are consequently simulated to meet hourly power demand in various sites. The solar/wind fraction and net present cost of the systems are then used as the technical and economic clustering variables, respectively. The clustering results are finally used as input to obtain novel hybrid solar/wind GIS maps. Iran is selected as the case study to validate the proposed methodology and detail its applicability. Ten minute annual global horizontal radiation, wind speed, and temperature data are analyzed, and the optimal, robust hybrid systems are simulated for various sites in order to classify the country. The generated GIS maps show that Iran can be efficiently clustered into four technical and five economic clusters under optimal conditions. The clustering results prove that Iran is mainly a solar country with approximately 74% solar power fraction under optimum conditions. A macroeconomic evaluation using DaSOSaCa also reveals that the nominal discount rate is recommended to be greater than 20% considering the current economic situation for the renewable energy sector in Iran. An environmental analysis results show that an average 106.68 tonCO 2

  12. A study on the power generation potential of mini wind turbine in east coast of Peninsular Malaysia

    Science.gov (United States)

    Basrawi, Firdaus; Ismail, Izwan; Ibrahim, Thamir Khalil; Idris, Daing Mohamad Nafiz Daing; Anuar, Shahrani

    2017-03-01

    A small-scale wind turbine is an attractive renewable energy source, but its economic viability depends on wind speed. The aim of this study is to determine economic viability of small-scale wind turbine in East Coast of Peninsular Malaysia. The potential energy generated has been determined by wind speed data and power curved of. Hourly wind speed data of Kuantan throughout 2015 was collected as the input. Then, a model of wind turbine was developed based on a commercial a 300W mini wind turbine. It was found that power generation is 3 times higher during northeast monsoon season at 15 m elevation. This proved that the northeast monsoon season has higher potential in generating power by wind turbine in East Coast of Peninsular Malaysia. However, only a total of 153.4 kWh/year of power can be generated at this condition. The power generator utilization factor PGUI or capacity ratio was merely 0.06 and it is not technically viable. By increasing the height of wind turbine to 60 m elevation, power generation amount drastically increased to 344 kWh/year, with PGUI of 0.13. This is about two-thirds of PGUI for photovoltaic technology which is 0.21 at this site. If offshore condition was considered, power generation amount further increased to 1,328 kWh/year with PGUI of 0.51. Thus, for a common use of mini wind turbine that is usually installed on-site at low elevation, it has low power generation potential. But, if high elevation as what large wind turbine needed is implemented, it is technically viable option in East Coast of Peninsular Malaysia.

  13. RANS study of unsteady flow around a profile blade : application to stall of horizontal axis wind turbine

    Energy Technology Data Exchange (ETDEWEB)

    Belkheir, N. [Khemis Miliana Univ., Ain Defla (Algeria); Dizene, R. [Univ. des Sciences et de la Technologie Houari Boumediene, Algiers (Algeria). Laboratoire de Mecanique Avancee; Khelladi, S.; Massouh, F.; Dobrev, I. [Arts et Metiers Paris Tech., Paris (France)

    2010-07-01

    The shape of an airfoil is designed to achieve the best aerodynamic performance. An aerofoil section undergoes dynamic stall when subjected to any form of unsteady angle of pitch. The study of a horizontal-axis wind turbine (HAWT) under wind operating conditions is complex because it is subject to instantaneous speed and wind direction variation. When turbine blades are driven into a dynamic stall, the lift coefficient drops suddenly resulting in a degradation in aerodynamic performance. This study presented steady and unsteady wind load predictions over an oscillating S809 airfoil tested in a subsonic wind tunnel. A model of sinusoidal pitch oscillations was used. The values for the angles of attack in steady state ranged from -20 to +40 degrees. The model considered 3 frequencies and 2 amplitudes. The two-dimensional numerical model simulated the instantaneous change of wind direction with respect to the turbine blade. Results were compared with data measurements of S809 aerofoil. Reasonable deviations were obtained between the predicted and experimental results for pitch oscillations. The URANS approach was used to predict the stall while the software FLUENT was used for the numerical solution. It was concluded that the behaviour of the unsteady flow in the wind farm must be considered in order to obtain an accurate estimate of the wind turbine aerodynamic load. 12 refs., 5 figs.

  14. The Offshore New European Wind Atlas

    Science.gov (United States)

    Karagali, I.; Hahmann, A. N.; Badger, M.; Hasager, C.; Mann, J.

    2017-12-01

    The New European Wind Atlas (NEWA) is a joint effort of research agencies from eight European countries, co-funded under the ERANET Plus Program. The project is structured around two areas of work: development of dynamical downscaling methodologies and measurement campaigns to validate these methodologies, leading to the creation and publication of a European wind atlas in electronic form. This atlas will contain an offshore component extending 100 km from the European coasts. To achieve this, mesoscale models along with various observational datasets are utilised. Scanning lidars located at the coastline were used to compare the coastal wind gradient reproduced by the meso-scale model. Currently, an experimental campaign is occurring in the Baltic Sea, with a lidar located in a commercial ship sailing from Germany to Lithuania, thus covering the entire span of the south Baltic basin. In addition, satellite wind retrievals from scatterometers and Synthetic Aperture Radar (SAR) instruments were used to generate mean wind field maps and validate offshore modelled wind fields and identify the optimal model set-up parameters.The aim of this study is to compare the initial outputs from the offshore wind atlas produced by the Weather & Research Forecasting (WRF) model, still in pre-operational phase, and the METOP-A/B Advanced Scatterometer (ASCAT) wind fields, reprocessed to stress equivalent winds at 10m. Different experiments were set-up to evaluate the model sensitivity for the various domains covered by the NEWA offshore atlas. ASCAT winds were utilised to assess the performance of the WRF offshore atlases. In addition, ASCAT winds were used to create an offshore atlas covering the years 2007 to 2016, capturing the signature of various spatial wind features, such as channelling and lee effects from complex coastal topographical elements.

  15. On the aerodynamics of a vertical axis wind turbine wake : An experimental and numerical study

    NARCIS (Netherlands)

    Tescione, G.

    2016-01-01

    THE recent trend in wind energy industry, with the increasing deployment of offshore wind farms, has revived the interest in the concept of a vertical axis wind turbine. The scientific, technological and economical challenges of the next generation of wind turbines indicate that a transformative

  16. Review of relevant studies of isolated systems[Integration of wind energy

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, L.H.; Lundsager, P.

    2000-12-01

    The report presents the results of a review of studies relating to integration of wind energy in isolated power supply systems, based on a systematic literature survey. The purpose of the study is to develop a methodology consisting of a set of guidelines for wind energy projects in isolated energy systems and a set of tools and models that are operational on an engineering level. The review is based on a literature search in the ETDE Energy Database with a main search covering the period 7/88 to 6/97 and supplemented by partial update periods. A few newer references have been included in the review, most notably the IEC/PAS 62111 specification. The amount of wind energy literature related to the subject is excessively large, and a complete review in which every relevant abstract is identified and examined is not feasible within the framework of this (or probably any other) study. The review results have been organised according to the following keywords: methods & guides, economics, concept of application, system solutions, case studies, financial programmes, dedicated software tools. None of the found references presents methods or tools that contradict the philosophy of Risoe's methodology as it is described in the report. It is therefore concluded that Risoe's methodology makes a good platform for further development. (au)

  17. The wind forecasting improvement project. Description and results from the Southern study region

    Energy Technology Data Exchange (ETDEWEB)

    Freedman, Jeffrey [AWS Truepower LLC, Albany, NY (United States); Benjamin, Stan; Wilczak, James [National Oceanic and Atmospheric Administration, Washington, DC and Boulder, CO (United States)] [and others

    2012-07-01

    The Wind Forecasting Improvement Project (WFIP) is a multi-year U.S. Department of Energy (DOE)/National Oceanographic and Atmospheric Administration (NOAA) sponsored study whose main purpose is to demonstrate the scientific and economic benefits of additional atmospheric observations and model enhancements on wind energy production forecasts. WFIP covers two geographical regions of the U.S.: (1) the upper Great Plains, or Northern Study Area, and (2) most of Texas-the Southern Study Area. The Southern campaign is being led by AWS Truepower LLC, and includes a team of private, government, and academic partners with collective experience and expertise in all facets required to ensure a successful completion of the project. In addition presenting a summary of the state-of-the-art forecasting techniques used and phenomena-based analysis mentioned above, a brief synopsis of how ''lessons learned'' from the WFIP Southern Study Area can be articulated and applied to other wind resource regions will be described. (orig.)

  18. Design study of a 10 MW MgB2 superconductor direct drive wind turbine generator

    DEFF Research Database (Denmark)

    Abrahamsen, Asger Bech; Magnusson, Niklas; Liu, Dong

    2014-01-01

    A design study of a 10 MW direct drive wind turbine generator based on MgB2 superconducting wires is presented and the cost of the active materials of the generator is estimated to be between 226 €/kW and 84 €/kw, which is lower than the threshold values of 300 €/kW of the INNWIND.EU project. A n...

  19. A study of the radar backscattering from the breaking of wind waves on the sea

    International Nuclear Information System (INIS)

    Ivanov, V.A.; Yurovskij, Yu.Yu.; Malinovskij, V.V.

    2011-01-01

    The results of a field study of the relationship between radar backscattering parameters and geometrical characteristics of the wind wave breaking are presented. The radar cross-section of a whitecap is found to be proportional to the breaking crest length. It is shown that the accounting for a change of the non-Bragg scattering in the presence of an oil slick on the sea surface allows one to interpret experimental data correctly.

  20. Wakes behind wind turbines. Studies on tip vortex evolution and stability

    Energy Technology Data Exchange (ETDEWEB)

    Odemark, Ylva

    2012-07-01

    The increased fatigue loads and decreased power output of a wind turbine placed in the wake of another turbine is a well-known problem when building new wind power farms. In order to better estimate the total power output of a wind power farm, knowledge about the development and stability of wind turbine wakes is crucial. In the present thesis, the wake behind a small-scale model turbine was investigated experimentally in a wind tunnel. The velocity in the wake was measured with hot-wire anemometry, for different free stream velocities and tip speed ratios. To characterize the behaviour of the model turbine, the power output, thrust force and rotational frequency of the model were also measured. These results were then compared to calculations using the Blade Element Momentum (BEM) method. New turbine blades for the model was constructed using the same method, in order to get an estimate of the distribution of the lift and drag forces along the blades. This information is needed for comparisons with certain numerical simulations, which however remains to be performed.By placing the turbine at different heights in a turbulent boundary layer, the effects of forest turbulence on wind turbine outputs (power and thrust) could also be investigated.The evolution of the tip vortices shed from the turbine blades was studied by performing velocity measurements around the location of the tip vortex breakdown. The vortices' receptivity to disturbances was then studied by introducing a disturbance in the form of two pulsed jets, located in the rear part of the nacelle. In order to introduce a well-defined disturbance and perform phase-locked measurements, a new experimental setup was constructed and successfully tested for two different disturbance frequencies. The mean stream wise velocity and the stream wise turbulence intensity was found to scale well with the free stream velocity and the spreading of the wake was found to be proportional to the square root of the

  1. Study of large-scale vertical axis wind turbine wake through numerical modelling and fullscale experiments

    DEFF Research Database (Denmark)

    Immas, Alexandre; Kluczewska-Bordier, Joanna; Beneditti, Pascal

    Offshore wind capacity is increasing exponentially over the years in Europe, taking advantage of the strong winds available over the ocean and of the political incentives to reduce greenhouse gases. The technology is however not yet competitive when compared to fossil fuels or onshore wind. One k...... horizontal axis wind turbine wind farm....... improvement that could make offshore wind more attractive is the reduction of the wake effect [1]. The latter corresponds to the velocity deficit generated by each wind turbine wake which affects the production of the others. This effect accounts for approximately 10% of the energy losses for a typical......Offshore wind capacity is increasing exponentially over the years in Europe, taking advantage of the strong winds available over the ocean and of the political incentives to reduce greenhouse gases. The technology is however not yet competitive when compared to fossil fuels or onshore wind. One key...

  2. Study of the stall delay phenomenon and of wind turbine blade dynamics using numerical approaches and NREL's wind tunnel tests

    Energy Technology Data Exchange (ETDEWEB)

    Breton, Simon-Philippe

    2008-06-15

    the modeling of the stall phenomenon which involves very complex aerodynamics. The NREL wind tunnel results were further scrutinized in term of the root flapwise and edgewise bending moments. This allowed to study the dynamics of the NREL blades, at the same time as verifying the consistency between these moments and different loads measured in these tests. Measurements of these moments at the root of the rigid NREL blades in head-on flow showed vibrations corresponding to the two first oscillation modes of the blades, in respectively the flapwise and edgewise directions. These features observed in both an upwind and a downwind configuration were presumed to follow from the presence of the tower. In the downwind configuration, dynamic effects affecting one blade when going through the shadow of the tower were found to be transmitted to the other blade in both the teetered and the rigid configurations. Modelling of the root edgewise and flapwise bending moments was performed by calculating two dynamic estimates based on forces measured respectively along the blade and in the hub region. The simulations generally reproduced the dynamic effects well, and they suggested a systematic error in the measurement of the root flapwise bending moment in the upwind configuration. Inaccuracies in measuring the tangential forces on the blade at high wind speeds were also detected. Offshore wind energy, that is expected to soon lead the development of the wind energy technology, was thereafter studied, where downwind turbines that were given special attention in the dynamic analysis above might reveal themselves as a more adapted solution. The many advantages as well as challenges related to this technology were acknowledged. The status of this technology was investigated in both Europe and North America, and it revealed that Europe is in advance regarding all aspects of wind energy over North America, where it still is at a planning stage. Important plans were however found to exist

  3. A sensitivity study for soil-structure interaction

    International Nuclear Information System (INIS)

    Kunar, R.R.; White, D.C.; Ashdown, M.J.; Waker, C.H.; Daintith, D.

    1981-01-01

    This paper presents the results of a study in which the sensitivity of a containment building typical of one type of construction used in the nuclear reprocessing industry is examined for variations in soil data and seismic input. A number of dynamic soil-structure interaction analyses are performed on the structure and its foundations using parametric variations of the depth of soil layer, soil material properties, bedrock flexibility, seismic input location and time and phase characteristics of the earthquake excitation. Previous experience is combined with the results obtained to gneralise conclusions regarding the conditions under which each of the uncertainties will be significant enough to merit proper statistical treatment. (orig.)

  4. Ambient pressure sensitivity of microbubbles investigated through a parameter study

    DEFF Research Database (Denmark)

    Andersen, Klaus Scheldrup; Jensen, Jørgen Arendt

    2009-01-01

    Measurements on microbubbles clearly indicate a relation between the ambient pressure and the acoustic behavior of the bubble. The purpose of this study was to optimize the sensitivity of ambient pressure measurements, using the subharmonic component, through microbubble response simulations....... The behavior of two microbubbles corresponding to two different contrast agents was investigated as a function of driving pulse and ambient overpressure, pov. Simulations of Levovist using a rectangular driving pulse show an almost linear reduction in the subharmonic component as pov is increased. For a 20...... found, although the reduction is not completely linear as a function of the ambient pressure....

  5. An FMEA-Based Risk Assessment Approach for Wind Turbine Systems: A Comparative Study of Onshore and Offshore

    Directory of Open Access Journals (Sweden)

    Mahmood Shafiee

    2014-02-01

    Full Text Available Failure mode and effects analysis (FMEA has been extensively used by wind turbine assembly manufacturers for analyzing, evaluating and prioritizing potential/known failure modes. However, several limitations are associated with its practical implementation in wind farms. First, the Risk-Priority-Number (RPN of a wind turbine system is not informative enough for wind farm managers from the perspective of criticality; second, there are variety of wind turbines with different structures and hence, it is not correct to compare the RPN values of different wind turbines with each other for prioritization purposes; and lastly, some important economical aspects such as power production losses, and the costs of logistics and transportation are not taken into account in the RPN value. In order to overcome these drawbacks, we develop a mathematical tool for risk and failure mode analysis of wind turbine systems (both onshore and offshore by integrating the aspects of traditional FMEA and some economic considerations. Then, a quantitative comparative study is carried out using the traditional and the proposed FMEA methodologies on two same type of onshore and offshore wind turbine systems. The results show that the both systems face many of the same risks, however there are some main differences worth considering.

  6. Grid Integration Research | Wind | NREL

    Science.gov (United States)

    Grid Integration Research Grid Integration Research Researchers study grid integration of wind three wind turbines with transmission lines in the background. Capabilities NREL's grid integration electric power system operators to more efficiently manage wind grid system integration. A photo of

  7. Cometary jets in interaction with the solar wind: a hybrid simulation study

    Science.gov (United States)

    Wiehle, Stefan; Motschmann, Uwe; Gortsas, Nikolaos; Mueller, Joachim; Kriegel, Hendrik; Koenders, Christoph; Glassmeier, Karl-Heinz

    The effect of a cometary jet on the solar wind interaction is studied using comet 67P/Churyumov-Gerasimenko as case study. This comet is the target of the Rosetta-mission which will arrive in 2014. Observations suggest that cometary outgassing is confined to only a few percent of the cometary surface; thus, the measurement of jets is expected. Most former comet simulations did not attend to this fact and used an isotropic outgassing scheme or simplified outgassing patterns. Here, a single sun-facing jet is set to be the only source of cometary gas produc-tion. Using an analytic profile, this outgassing jet was implemented in a hybrid simulation code which treats protons and cometary heavy ions as particles and electrons as massless fluid. In a simulation series, the geometric parameters of the jet were varied to study the effect of different opening angles while the integrated outgassing rate remained constant. It was shown that the resulting solar wind interaction is highly dependent on the geometry of the jet. The plasma-structures like the solar wind pile-up found in the situation with isotropic outgassing are moved more and more sunward as the opening angle of the jet decreases. Furthermore, the cometary ion tail shows some kind of splitting which is not known from isotropic models.

  8. Wind energy technology development and diffusion: a case study of Inner Mongolia, China

    International Nuclear Information System (INIS)

    Xiliang Zhang; Shuhua Gu; Wenqiang Liu; Lin Gan

    2001-01-01

    This article reviews the spread of small household wind generators and the development of wind farms in Inner Mongolia, China with emphasis on policy and institutional perspectives. It analyses the patterns of wind technology dissemination within social, economic, and environmental contexts. It also discusses international investment and technology transfer relating to wind energy technology. The economics of windfarm development are examined and the role of alternative policy instruments analysed. Major constraints to wind technology development are identified and relevant policy recommendations suggested. (Author)

  9. Wind energy technology development and diffusion: a case study of Inner Mongolia, China

    International Nuclear Information System (INIS)

    Zhang Xiliang; Liu Wenqiang; Gu Shuhua; Gan Lin

    2001-01-01

    This article reviews the spread of small household wind generators and the development of wind farms in Inner Mongolia, China with emphasis on policy and institutional perspectives. It analyzes the patterns of wind technology dissemination within social, economic, and environmental contexts. It also discusses international investment and technology transfer relating to wind energy technology. The economics of windfarm development are examined and the role of alternative policy instruments analyzed. Major constraints to wind technology development are identified and relevant policy recommendations suggested. (author)

  10. Reindeer and Wind Power - Study from the installation of two wind farms in Mala sameby; Renar och Vindkraft - Studie fraan anlaeggningen av tvaa vindkraftparker i Malaa sameby

    Energy Technology Data Exchange (ETDEWEB)

    Skarin, Anna; Nellemann, Christian; Sandstroem, Per; Roennegaard, Lars; Lundqvist, Henrik

    2013-05-15

    In the track of ever-expanding new infrastructure, such as wind power, roads and power lines, it becomes increasingly important to map and understand how free-ranging animals and wildlife respond. During the past decades, human - rangifer interactions have been assessed in over a hundred studies, with a strong bias on wild reindeer and caribou, although more recently also studies on domesticated reindeer in Norway, Finland, Sweden and Russia have been done with similar results. To clarify further the possible responses of domesticated reindeer to various disturbance sources, a review was made of over 15 existing disturbance studies of domesticated reindeer, we also discuss the effect of domestication on reindeer. The review shows the same pattern of avoidance in domesticated reindeer as for wild reindeer and caribou despite the domestication process. Sami reindeer husbandry today is an extensive form of pastoralism, which has led to a low degree of tameness among the reindeer. Domesticated reindeer can avoid infrastructure and human activity up to 12 km from the disturbance source and the avoided distance may shift between seasons and years and type of disturbance source, as well as diminish during periods of extreme starvation or insect harassment, similar to observation in wild reindeer and caribou. To get an overall picture of how the reindeer use their grazing land, it is therefore important to study large-scale and long-term habitat use of the reindeer whether they are domesticated or not. In this report, we want to share new information on how existing infrastructure such as roads and power lines in the landscape and construction phase of a new infrastructure for a wind farm affects the free roaming of the reindeer in a summer grazing area in a managed forest in northern Sweden.

  11. Nordic reference study on uncertainty and sensitivity analysis

    International Nuclear Information System (INIS)

    Hirschberg, S.; Jacobsson, P.; Pulkkinen, U.; Porn, K.

    1989-01-01

    This paper provides a review of the first phase of Nordic reference study on uncertainty and sensitivity analysis. The main objective of this study is to use experiences form previous Nordic Benchmark Exercises and reference studies concerning critical modeling issues such as common cause failures and human interactions, and to demonstrate the impact of associated uncertainties on the uncertainty of the investigated accident sequence. This has been done independently by three working groups which used different approaches to modeling and to uncertainty analysis. The estimated uncertainty interval for the analyzed accident sequence is large. Also the discrepancies between the groups are substantial but can be explained. Sensitivity analyses which have been carried out concern e.g. use of different CCF-quantification models, alternative handling of CCF-data, time windows for operator actions and time dependences in phase mission operation, impact of state-of-knowledge dependences and ranking of dominating uncertainty contributors. Specific findings with respect to these issues are summarized in the paper

  12. Sensitivity analysis in multiple imputation in effectiveness studies of psychotherapy.

    Science.gov (United States)

    Crameri, Aureliano; von Wyl, Agnes; Koemeda, Margit; Schulthess, Peter; Tschuschke, Volker

    2015-01-01

    The importance of preventing and treating incomplete data in effectiveness studies is nowadays emphasized. However, most of the publications focus on randomized clinical trials (RCT). One flexible technique for statistical inference with missing data is multiple imputation (MI). Since methods such as MI rely on the assumption of missing data being at random (MAR), a sensitivity analysis for testing the robustness against departures from this assumption is required. In this paper we present a sensitivity analysis technique based on posterior predictive checking, which takes into consideration the concept of clinical significance used in the evaluation of intra-individual changes. We demonstrate the possibilities this technique can offer with the example of irregular longitudinal data collected with the Outcome Questionnaire-45 (OQ-45) and the Helping Alliance Questionnaire (HAQ) in a sample of 260 outpatients. The sensitivity analysis can be used to (1) quantify the degree of bias introduced by missing not at random data (MNAR) in a worst reasonable case scenario, (2) compare the performance of different analysis methods for dealing with missing data, or (3) detect the influence of possible violations to the model assumptions (e.g., lack of normality). Moreover, our analysis showed that ratings from the patient's and therapist's version of the HAQ could significantly improve the predictive value of the routine outcome monitoring based on the OQ-45. Since analysis dropouts always occur, repeated measurements with the OQ-45 and the HAQ analyzed with MI are useful to improve the accuracy of outcome estimates in quality assurance assessments and non-randomized effectiveness studies in the field of outpatient psychotherapy.

  13. Sensitivity studies for a space-based methane lidar mission

    Directory of Open Access Journals (Sweden)

    C. Kiemle

    2011-10-01

    Full Text Available Methane is the third most important greenhouse gas in the atmosphere after water vapour and carbon dioxide. A major handicap to quantify the emissions at the Earth's surface in order to better understand biosphere-atmosphere exchange processes and potential climate feedbacks is the lack of accurate and global observations of methane. Space-based integrated path differential absorption (IPDA lidar has potential to fill this gap, and a Methane Remote Lidar Mission (MERLIN on a small satellite in polar orbit was proposed by DLR and CNES in the frame of a German-French climate monitoring initiative. System simulations are used to identify key performance parameters and to find an advantageous instrument configuration, given the environmental, technological, and budget constraints. The sensitivity studies use representative averages of the atmospheric and surface state to estimate the measurement precision, i.e. the random uncertainty due to instrument noise. Key performance parameters for MERLIN are average laser power, telescope size, orbit height, surface reflectance, and detector noise. A modest-size lidar instrument with 0.45 W average laser power and 0.55 m telescope diameter on a 506 km orbit could provide 50-km averaged methane column measurement along the sub-satellite track with a precision of about 1% over vegetation. The use of a methane absorption trough at 1.65 μm improves the near-surface measurement sensitivity and vastly relaxes the wavelength stability requirement that was identified as one of the major technological risks in the pre-phase A studies for A-SCOPE, a space-based IPDA lidar for carbon dioxide at the European Space Agency. Minimal humidity and temperature sensitivity at this wavelength position will enable accurate measurements in tropical wetlands, key regions with largely uncertain methane emissions. In contrast to actual passive remote sensors, measurements in Polar Regions will be possible and biases due to aerosol

  14. Studies on radiation-sensitive nonsilver halide materials, (1)

    International Nuclear Information System (INIS)

    Komizu, Hideo; Honda, Koichi; Yabe, Akira; Kawasaki, Masami; Fujii, Etsuo

    1978-01-01

    In order to discover new radiation-sensitive nonsilver halide materials, the coloration based on the formation of Stenhouse salts was studied in the following three systems: (a) furfural-amine/HCl aq/methanol solution, (b) furfural-amine/polyhalogenide/PMMA matrix, (c) furfural-amine/PVC matrix. Firstly, forty-five aromatic amines were surveyed to find out the amines suitable for the color precursors (reactant from furfural and amine) in the system (a). As a result, the five amines, which gave the precursors in good yields by the reaction with furfural, were selected: m-nitroaniline, N-methylaniline, m-methyl-N-methylaniline, aniline, and o-methoxyaniline. Secondly, the coloration induced by electron beam bombardment was studied in the systems (b) and (c) containing the color precursors (the