scholarly journals Turbulence coherence and its impact on wind-farm power fluctuations

2018 ◽  
Vol 855 ◽  
pp. 1116-1129 ◽  
Author(s):  
Nicolas Tobin ◽  
Leonardo P. Chamorro
Keyword(s):  
Power Spectrum ◽  
Atmospheric Turbulence ◽  
Turbulent Diffusion ◽  
Wind Farm ◽  
Spectral Characteristics ◽  
Wind Farms ◽  
High Frequencies ◽  
Power Fluctuations ◽  
The Impact ◽  
Coherence Spectrum

Using a physics-based approach, we infer the impact of the coherence of atmospheric turbulence on the power fluctuations of wind farms. Application of the random-sweeping hypothesis reveals correlations characterized by advection and turbulent diffusion of coherent motions. Those contribute to local peaks and troughs in the power spectrum of the combined units at frequencies corresponding to the advection time between turbines, which diminish in magnitude at high frequencies. Experimental inspection supports the results from the random-sweeping hypothesis in predicting spectral characteristics, although the magnitude of the coherence spectrum appears to be over-predicted. This deviation is attributed to the presence of turbine wakes, and appears to be a function of the turbulence approaching the first turbine in a pair.

scholarly journals Spatiotemporal Correlations in the Power Output of Wind Farms: On the Impact of Atmospheric Stability

Energies ◽  
2019 ◽  
Vol 12 (8) ◽  
pp. 1486 ◽  
Author(s):  
Nicolas Tobin ◽  
Adam Lavely ◽  
Sven Schmitz ◽  
Leonardo P. Chamorro
Keyword(s):  
Power Output ◽  
Wind Farm ◽  
Statistical Significance ◽  
Atmospheric Stability ◽  
Wind Farms ◽  
Temporal Correlations ◽  
Theoretical Predictions ◽  
Power Variance ◽  
Ambient Turbulence ◽  
The Impact

The dependence of temporal correlations in the power output of wind-turbine pairs on atmospheric stability is explored using theoretical arguments and wind-farm large-eddy simulations. For this purpose, a range of five distinct stability regimes, ranging from weakly stable to moderately convective, were investigated with the same aligned wind-farm layout used among simulations. The coherence spectrum between turbine pairs in each simulation was compared to theoretical predictions. We found with high statistical significance (p < 0.01) that higher levels of atmospheric instability lead to higher coherence between turbines, with wake motions reducing correlations up to 40%. This is attributed to higher dominance of atmospheric motions over wakes in strongly unstable flows. Good agreement resulted with the use of an empirical model for wake-added turbulence to predict the variation of turbine power coherence with ambient turbulence intensity (R 2 = 0.82), though other empirical relations may be applicable. It was shown that improperly accounting for turbine–turbine correlations can substantially impact power variance estimates on the order of a factor of 4.

An ecosystem approach for studying the impact of offshore wind farms: a French case study

2018 ◽  
Vol 77 (3) ◽  
pp. 1238-1246 ◽  
Author(s):  
Jean-Philippe Pezy ◽  
Aurore Raoux ◽  
Jean-Claude Dauvin
Keyword(s):  
Network Analysis ◽  
Wind Farm ◽  
Wind Farms ◽  
Sampling Strategy ◽  
Ecosystem Approach ◽  
Offshore Wind ◽  
Ecosystem Structure ◽  
Offshore Wind Farms ◽  
Ecopath Model ◽  
The Impact

Abstract The French government is planning the construction of offshore wind farms (OWF) in the next decade (around 2900 MW). Following the European Environmental Impact Assessment Directive 85/337/EEC, several studies have been undertaken to identify the environmental conditions and ecosystem functioning at selected sites prior to OWF construction. However, these studies are generally focused on the conservation of some species and there is no holistic approach for analysing the effects arising from OWF construction and operation. The objective of this article is to promote a sampling strategy to collect data on the different ecosystem compartments of the future Dieppe-Le Tréport (DLT) wind farm site, adopting an ecosystem approach, which could be applied to other OWFs for the implementation of a trophic network analysis. For that purpose, an Ecopath model is used here to derive indices from Ecological Network Analysis (ENA) to investigate the ecosystem structure and functioning. The results show that the ecosystem is most likely detritus-based, associated with a biomass dominated by bivalves, which could act as a dead end for a classic trophic food web since their consumption by top predators is low in comparison to their biomass. The systemic approach developed for DLT OWF site should be applied for other French and European installations of Offshore Wind Farm.

scholarly journals Noise assessment of the small-scale wind farm

2019 ◽  
Vol 112 ◽  
pp. 02011
Author(s):  
Cristian-Gabriel Alionte ◽  
Daniel-Constantin Comeaga
Keyword(s):  
Power Systems ◽  
Large Scale ◽  
Wind Farm ◽  
Wind Farms ◽  
Small Scale ◽  
Large Power ◽  
Small Power ◽  
Noise Assessment ◽  
The Impact

The importance of renewable energy and especially of eolian systems is growing. For this reason, we propose the investigation of an important pollutant - the noise, which has become so important that European Commission and European Parliament introduced Directive 2002/49/CE relating to the assessment and management of environmental noise. So far, priority has been given to very large-scale systems connected to national energy systems, wind farms whose highly variable output power could be regulated by large power systems. Nowadays, with the development of small storage capacities, it is feasible to install small power wind turbines in cities of up to 10,000 inhabitants too. As a case study, we propose a simulation for a rural locality where individual wind units could be used. This specific case study is interesting because it provides a new perspective of the impact of noise on the quality of life when the use of this type of system is implemented on a large scale. This option, of distributed and small power wind turbine, can be implemented in the future as an alternative or an adding to the common systems.

An Analysis about Wind Farm Construction Based on the Perspective of the Development of Ecological Environment

2013 ◽  
Vol 772 ◽  
pp. 619-621
Author(s):  
Zi Wei Bai
Keyword(s):  
Wind Power ◽  
Electromagnetic Interference ◽  
Wind Farm ◽  
Wind Farms ◽  
Control Measures ◽  
Ecological Environment ◽  
Public Attention ◽  
Natural Landscape ◽  
And Control ◽  
The Impact

Advantages of wind power are self-evident, but the impact of wind power project on the local ecological environment and natural landscape is also increasingly subject to public attention. It mainly reflects in the visual pollution of the wind turbine (or natural landscape problems), noise, bird safety and electromagnetic interference. The paper analyzed the impact of wind farms on the environment, and recommended appropriate preventions and control measures to reduce it to an acceptable level.

TROUBLES WITH A WIND FARM PROECT

2020 ◽  
Vol 7 (2) ◽  
Author(s):  
Keenan Nakagawa ◽  
Amarjit Singh
Keyword(s):  
Renewable Energy ◽  
Wind Energy ◽  
Wind Farm ◽  
Focal Point ◽  
Wind Farms ◽  
Adverse Health Effects ◽  
New Development ◽  
Local Residents ◽  
Native Birds ◽  
The Impact

The Kahuku Wind Farm of Hawaii has been laden with controversy since its inception in 2011. Although it was one of the two wind farms on Oahu responsible for supplying a combined 14% of the island’s renewable energy in 2018, citizens have been outspoken in their criticism of the facility. Local residents have cited concerns regarding adverse health effects to the surrounding community, as well as deaths of native birds and endangered bats caused by the turbines. The impact on the Hawaiian hoary bat population has been a focal point of numerous complaints, as more bats are being killed than initially predicted. To the dismay of their opponents, eight additional turbines are being erected in Kahuku as part of the Na Pua Makani Wind Energy Project. And, as of November 2019, approximately 200 individuals have been arrested while protesting it. To add to the controversy, wind farm officials are currently facing legal hurdles, as challengers are skeptical on whether the project’s environmental review correctly estimates the number of birds and bats that will fall victim to this new development. The purpose of this study is to analyze and evaluate the issues associated with the Kahuku Wind Farm and Na Pua Makani Wind Energy Project, as well as the position and arguments of stakeholders and litigants.

Study on a Service Mechanism that Wind/Photovoltaic/Energy Storage Power Station Help Wind Farms Tracking Generation Schedule Curve

2013 ◽  
Vol 860-863 ◽  
pp. 1909-1913
Author(s):  
Hai Xiang Xu ◽  
Peng Wang ◽  
Xiao Meng Ren
Keyword(s):  
Energy Storage ◽  
Wind Power ◽  
Wind Farm ◽  
Wind Farms ◽  
Power Station ◽  
Forecasting Accuracy ◽  
Wind Power Forecasting ◽  
Assessment Standard ◽  
The Impact ◽  
Power Forecasting

At present, the technology of wind power forecasting isn‘t mature enough in china, so some grid-connected wind farms will be assessed when theirs power forecasting accuracy cant reach the assessment standard. In response to the situation, combined with the characteristics of WPSPS and wind farms, this paper designs a service mechanism that WPSPS help wind farms tracking generation schedule curve, namely, encouraging WPSPS to supply output compensation service for wind farm by market means to increase the accuracy of wind power forecasting. By this mechanism, not only WPSPS and wind farms will achieve win-win, but also the impact on the grid caused by fluctuations of wind powers output will reduce.

scholarly journals Assessing the impact of marine wind farms on birds through movement modelling

2012 ◽  
Vol 9 (74) ◽  
pp. 2120-2130 ◽  
Author(s):  
Elizabeth A. Masden ◽  
Richard Reeve ◽  
Mark Desholm ◽  
Anthony D. Fox ◽  
Robert W. Furness ◽  
...  
Keyword(s):  
Wind Farm ◽  
Wind Farms ◽  
Offshore Wind ◽  
Somateria Mollissima ◽  
Trajectory Data ◽  
Power Sector ◽  
Planning Stage ◽  
Movement Models ◽  
Competing Models ◽  
The Impact

Advances in technology and engineering, along with European Union renewable energy targets, have stimulated a rapid growth of the wind power sector. Wind farms contribute to carbon emission reductions, but there is a need to ensure that these structures do not adversely impact the populations that interact with them, particularly birds. We developed movement models based on observed avoidance responses of common eider Somateria mollissima to wind farms to predict, and identify potential measures to reduce, impacts. Flight trajectory data that were  collected post-construction of the Danish Nysted offshore wind farm were used to parameterize competing models of bird movements around turbines. The model most closely fitting the observed data incorporated individual variation in the minimum distance at which birds responded to the turbines. We show how such models can contribute to the spatial planning of wind farms by assessing their extent, turbine spacing and configurations on the probability of birds passing between the turbines. Avian movement models can make new contributions to environmental assessments of wind farm developments, and provide insights into how to reduce impacts that can be identified at the planning stage.

scholarly journals Aligned and Staggered Layouts: What is the Impact on Wind Farms Land-Use?

2020 ◽  
Author(s):  
Rafael Valotta Rodrigues ◽  
Corinne Lengsfeld
Keyword(s):  
Land Use ◽  
Output Power ◽  
Wind Farm ◽  
Wind Farms ◽  
Short Term ◽  
Continuous Increase ◽  
Onshore Wind ◽  
Wake Interaction ◽  
The Impact ◽  
Blade Element

The use of wind energy has been developing fast over the last years. The global cumulative wind power capacity increased by 10.5% in 2019, most of which comes from onshore wind farms. One of the consequences of this continuous increase is the use of land for onshore wind farms. There are already cases worldwide where lack of well-established plans and strategies have caused delays in projects. The need for efficiently using land for wind farms will be mandatory in the short term. In this work, we present a numerical analysis to evaluate wind farm land-use. By defining the ratio between mechanical output power over an area as a parameter called land-use ratio, this work focused on comparing several cases of aligned and staggered layouts. Mechanical output power was estimated using a validated code based on Blade Element Momentum code, and the wake velocities and wake interaction effects were estimated using a validated wind turbine CFD model. In terms of output power, staggered designs are more efficient than aligned designs. However, the results showed that even though staggered designs produced higher output power, aligned farms with tight lateral spacing could be as efficient as staggered ones in terms of land-use but using fewer turbines. In summary, tightly aligned designs should be a tendency in the future towards efficient use of land in wind farms.

scholarly journals Cost Benefit of Implementing Advanced Monitoring and Predictive Maintenance Strategies for Offshore Wind Farms

Energies ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4922
Author(s):  
Alan Turnbull ◽  
James Carroll
Keyword(s):  
Wind Farm ◽  
Cost Benefit ◽  
Wind Farms ◽  
Cost Effective ◽  
Predictive Maintenance ◽  
Offshore Wind ◽  
Component Failure ◽  
Maintenance Strategies ◽  
Early Results ◽  
The Impact

Advancements in wind turbine condition monitoring systems over the last decade have made it possible to optimise operational performance and reduce costs associated with component failure and other unplanned maintenance activities. While much research focuses on providing more automated and accurate fault diagnostics and prognostics in relation to predictive maintenance, efforts to quantify the impact of such strategies have to date been comparatively limited. Through time-based simulation of wind farm operation, this paper quantifies the cost benefits associated with predictive and condition-based maintenance strategies, taking into consideration both direct O&M costs and lost production. Predictive and condition-based strategies have been modelled by adjusting known component failure and repair rates associated with a more reactive approach to maintenance. Results indicate that up to 8% of direct O&M costs can be saved through early intervention along with up to 11% reduction in lost production, assuming 25% of major failures of the generator and gearbox can be diagnosed through advanced monitoring and repaired before major replacement is required. Condition-based approaches can offer further savings compared to predictive strategies by utilising more component life before replacement. However, if weighing up the risk between component failure and replacing a component too early, results suggest that it is more cost effective to intervene earlier if heavy lift vessels can be avoided, even if that means additional major repairs are required over the lifetime of the site.

scholarly journals A pressure-driven atmospheric boundary layer model satisfying Rossby and Reynolds number similarity

2021 ◽  
Vol 6 (3) ◽  
pp. 777-790
Author(s):  
Maarten Paul van der Laan ◽  
Mark Kelly ◽  
Mads Baungaard
Keyword(s):  
Boundary Layer ◽  
Reynolds Number ◽  
Atmospheric Boundary Layer ◽  
Wind Farm ◽  
Three Dimensional ◽  
Computation Time ◽  
Wind Farms ◽  
The Mean ◽  
The Impact ◽  
Pressure Driven

Abstract. Idealized models of the atmospheric boundary layer (ABL) can be used to leverage understanding of the interaction between the ABL and wind farms towards the improvement of wind farm flow modeling. We propose a pressure-driven one-dimensional ABL model without wind veer, which can be used as an inflow model for three-dimensional wind farm simulations to separately demonstrate the impact of wind veer and ABL depth. The model is derived from the horizontal momentum equations and follows both Rossby and Reynolds number similarity; use of such similarity reduces computation time and allows rational comparison between different conditions. The proposed ABL model compares well with solutions of the mean momentum equations that include wind veer if the forcing variable is employed as a free parameter.

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