Validation of boundary layer parameterization schemes in the weather research and forecasting model under the aspect of offshore wind energy applications- Part I: Average wind speed and wind shear

Optimization of the autonomous wind-diesel plants composition and of their power for guaranteed energy supply, despite the long history of research, the diversity of approaches and methods, is an urgent problem. In this paper, a detailed analysis of the wind energy characteristics is proposed to shape an autonomous power system for a guaranteed power supply with predominance wind energy. The analysis was carried out on the basis of wind speed measurements in the south of the European part of Russia during 8 months at different heights with a discreteness of 10 minutes. As a result, we have obtained a sequence of average daily wind speeds and the sequences constructed by arbitrary variations in the distribution of average daily wind speeds in this interval. These sequences have been used to calculate energy balances in systems (wind turbines + diesel generator + consumer with constant and limited daily energy demand) and (wind turbines + diesel generator + consumer with constant and limited daily energy demand + energy storage). In order to maximize the use of wind energy, the wind turbine integrally for the period in question is assumed to produce the required amount of energy. For the generality of consideration, we have introduced the relative values of the required energy, relative energy produced by the wind turbine and the diesel generator and relative storage capacity by normalizing them to the swept area of the wind wheel. The paper shows the effect of the average wind speed over the period on the energy characteristics of the system (wind turbine + diesel generator + consumer). It was found that the wind turbine energy produced, wind turbine energy used by the consumer, fuel consumption, and fuel economy depend (close to cubic dependence) upon the specified average wind speed. It was found that, for the same system with a limited amount of required energy and high average wind speed over the period, the wind turbines with lower generator power and smaller wind wheel radius use wind energy more efficiently than the wind turbines with higher generator power and larger wind wheel radius at less average wind speed. For the system (wind turbine + diesel generator + energy storage + consumer) with increasing average speed for a given amount of energy required, which in general is covered by the energy production of wind turbines for the period, the maximum size capacity of the storage device decreases. With decreasing the energy storage capacity, the influence of the random nature of the change in wind speed decreases, and at some values of the relative capacity, it can be neglected.

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Wind Energy Potential in Nine Coastal Sites in Malaysia

مجلة جامعة فلسطين التقنية للأبحاث ◽

10.53671/ptukrj.v1i1.7 ◽

2013 ◽

Vol 1 (1) ◽

pp. 10-15

Author(s):

Kamaruzzaman Sopian ◽

Tamer Khatib

Keyword(s):

Wind Speed ◽

Wind Energy ◽

Data Bank ◽

Energy Potential ◽

Average Wind Speed ◽

Speed Distribution ◽

Average Wind ◽

Wind Speed Distribution ◽

Wind Energy Potential ◽

Swept Area

In this paper, the wind energy potential in Malaysia is examined by analyzing hourly wind speed data for nine coastal sites namely Bintulu, Kota Kinabalu, Kuala Terengganu, Kuching, Kudat, Mersing, Sandakan, Tawau and Pulau Langkawi. The monthly averages of wind speed and wind energy are calculated. Moreover, the wind speed distribution histogram is constructed for these sites. The results showed that the average wind speed for these sites is in the range of (1.8-2.9) m/s while the annual energy of the wind hitting a wind turbine with a 1 m2 swept area is in the range of (15.4-25.2) kWh/m2.annum. This paper provides a data bank for wind energy for Malaysia.

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An Evaluation of the Wind Energy Resources along the Spanish Continental Nearshore

Energies ◽

10.3390/en13153986 ◽

2020 ◽

Vol 13 (15) ◽

pp. 3986 ◽

Cited By ~ 1

Author(s):

Florin Onea ◽

Andrés Ruiz ◽

Eugen Rusu

Keyword(s):

Wind Speed ◽

Wind Energy ◽

Wind Turbines ◽

Offshore Wind ◽

Time Interval ◽

Average Wind Speed ◽

Important Conclusion ◽

Comprehensive Picture ◽

Mean Wind Speed ◽

Wind Resources

The main objective of the present work is to provide a comprehensive picture of the wind conditions in the Spanish continental nearshore considering a state-of-the-art wind dataset. In order to do this, the ERA5 wind data, covering the 20-year time interval from 1999 to 2018, was processed and evaluated. ERA stands for ’ECMWF Re-Analysis’ and refers to a series of research projects at ECMWF (European Centre for Medium-Range Weather Forecasts) which produced various datasets. In addition to the analysis of the wind resources (reported for a 100 m height), the performances of several wind turbines, ranging from 3 to 9.5 MW, were evaluated. From the analysis of the spatial maps it was observed that the Northern part of this region presents significant wind resources, the mean wind speed values exceeding 9 m/s in some locations. On the other hand, in regard to the Southern sector, more energetic conditions are visible close to the Strait of Gibraltar and to the Gulf of Lion. Nevertheless, from the analysis of the data corresponding to these two Southern nearshore points it was observed that the average wind speed was lower than 8 m/s in both summer and winter months. Regarding the considered wind turbines, the capacity factor did in general not exceed 20%—however, we did observe some peaks that could reach to 30%. Finally, it can be highlighted that the Northern part of the Spanish continental nearshore is significant from the perspective of extracting offshore wind energy, especially considering the technologies based on floating platforms. Furthermore, because of the clear synergy between wind and wave energy, which are characteristic to this coastal environment, an important conclusion of the present work is that the implementation of joint wind–wave projects might be effective in the Northwestern side of the Iberian nearshore.

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Large-eddy simulation sensitivities to variations of configuration and forcing parameters in canonical boundary-layer flows for wind energy applications

Wind Energy Science ◽

10.5194/wes-3-589-2018 ◽

2018 ◽

Vol 3 (2) ◽

pp. 589-613 ◽

Cited By ~ 11

Author(s):

Jeffrey D. Mirocha ◽

Matthew J. Churchfield ◽

Domingo Muñoz-Esparza ◽

Raj K. Rai ◽

Yan Feng ◽

...

Keyword(s):

Boundary Layer ◽

Wind Speed ◽

Wind Energy ◽

Physical Factors ◽

Convective Conditions ◽

Measurement Variability ◽

Energy Applications ◽

Model Configuration ◽

Large Eddy ◽

Quantities Of Interest

Abstract. The sensitivities of idealized large-eddy simulations (LESs) to variations of model configuration and forcing parameters on quantities of interest to wind power applications are examined. Simulated wind speed, turbulent fluxes, spectra and cospectra are assessed in relation to variations in two physical factors, geostrophic wind speed and surface roughness length, and several model configuration choices, including mesh size and grid aspect ratio, turbulence model, and numerical discretization schemes, in three different code bases. Two case studies representing nearly steady neutral and convective atmospheric boundary layer (ABL) flow conditions over nearly flat and homogeneous terrain were used to force and assess idealized LESs, using periodic lateral boundary conditions. Comparison with fast-response velocity measurements at 10 heights within the lowest 100 m indicates that most model configurations performed similarly overall, with differences between observed and predicted wind speed generally smaller than measurement variability. Simulations of convective conditions produced turbulence quantities and spectra that matched the observations well, while those of neutral simulations produced good predictions of stress, but smaller than observed magnitudes of turbulence kinetic energy, likely due to tower wakes influencing the measurements. While sensitivities to model configuration choices and variability in forcing can be considerable, idealized LESs are shown to reliably reproduce quantities of interest to wind energy applications within the lower ABL during quasi-ideal, nearly steady neutral and convective conditions over nearly flat and homogeneous terrain.

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Extreme wind shear events in US offshore wind energy areas and the role of induced stratification

Wind Energy Science ◽

10.5194/wes-6-1043-2021 ◽

2021 ◽

Vol 6 (4) ◽

pp. 1043-1059

Author(s):

Mithu Debnath ◽

Paula Doubrawa ◽

Mike Optis ◽

Patrick Hawbecker ◽

Nicola Bodini

Keyword(s):

Wind Speed ◽

Wind Energy ◽

Wind Shear ◽

New York State ◽

Vertical Gradient ◽

Detection Algorithm ◽

Offshore Wind ◽

Offshore Wind Energy ◽

High Wind ◽

Independent Events

Abstract. As the offshore wind industry emerges on the US East Coast, a comprehensive understanding of the wind resource – particularly extreme events – is vital to the industry's success. Such understanding has been hindered by a lack of publicly available wind profile observations in offshore wind energy areas. However, the New York State Energy Research and Development Authority recently funded the deployment of two floating lidars within two current lease areas off the coast of New Jersey. These floating lidars provide publicly available wind speed data from 20 to 200 m height with a 20 m vertical resolution. In this study, we leverage a year of these lidar data to quantify and characterize the frequent occurrence of high-wind-shear and low-level-jet events, both of which will have a considerable impact on turbine operation. In designing a detection algorithm for these events, we find that the typical, non-dimensional power-law-based wind shear exponent is insufficient to identify many of these extreme, high-wind-speed events. Rather, we find that the simple vertical gradient of wind speed better captures the events. Based on this detection method, we find that almost 100 independent events occur throughout the year with mean wind speed at 100 m height and wind speed gradient of 16 m s−1 and 0.05 s−1, respectively. The events have strong seasonal variability, with the highest number of events in summer and the lowest in winter. A detailed analysis reveals that these events are enabled by an induced stable stratification when warmer air from the south flows over the colder mid-Atlantic waters, leading to a positive air–sea temperature difference.

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Weibull Probability Distribution of Wind Speed for Gaza Strip for 10 Years

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.892.284 ◽

2019 ◽

Vol 892 ◽

pp. 284-291

Author(s):

Ahmed S.A. Badawi ◽

Nurul Fadzlin Hasbullah ◽

Siti Hajar Yusoff ◽

Sheroz Khan ◽

Aisha Hashim ◽

...

Keyword(s):

Wind Speed ◽

Probability Density Function ◽

Probability Distribution ◽

Wind Energy ◽

Probability Density ◽

Density Function ◽

Gaza Strip ◽

Actual Data ◽

Average Wind Speed ◽

Average Wind

The need of clean and renewable energy, as well as the power shortage in Gaza strip with few wind energy studies conducted in Palestine, provide the importance of this paper. Probability density function is commonly used to represent wind speed frequency distributions for the evaluation of wind energy potential in a specific area. This study shows the analysis of the climatology of the wind profile over the State of Palestine; the selections of the suitable probability density function decrease the wind power estimation error percentage. A selection of probability density function is used to model average daily wind speed data recorded at for 10 years in Gaza strip. Weibull probability distribution function has been estimated for Gaza based on average wind speed for 10 years. This assessment is done by analyzing wind data using Weibull probability function to find out the characteristics of wind energy conversion. The wind speed data measured from January 1996 to December 2005 in Gaza is used as a sample of actual data to this study. The main aim is to use the Weibull representative wind data for Gaza strip to show how statistical model for Gaza Strip over ten years. Weibull parameters determine by author depend on the pervious study using seven numerical methods, Weibull shape factor parameter is 1.7848, scale factor parameter is 4.3642 ms-1, average wind speed for Gaza strip based on 10 years actual data is 2.95 ms-1 per a day so the behavior of wind velocity based on probability density function show that we can produce energy in Gaza strip.

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Evaluation of wind speed estimates in reanalyses for wind energy applications

Advances in Science and Research ◽

10.5194/asr-18-115-2021 ◽

2021 ◽

Vol 18 ◽

pp. 115-126

Author(s):

Sebastian Brune ◽

Jan D. Keller ◽

Sabrina Wahl

Keyword(s):

Wind Speed ◽

Wind Energy ◽

Surface Characteristics ◽

Horizontal Resolution ◽

Hilly Terrain ◽

Average Wind Speed ◽

Wind Speeds ◽

Energy Applications ◽

Spatio Temporal ◽

Regional Reanalysis

Abstract. A correct spatio-temporal representation of retrospective wind speed estimates is of large interest for the wind energy sector. In this respect, reanalyses provide an invaluable source of information. However, the quality of the various reanalysis estimates for wind speed are difficult to assess. Therefore, this study compares wind measurements at hub heights from 14 locations in Central Europe with two global (ERA5, MERRA-2) and one regional reanalysis (COSMO-REA6). Employing metrics such as bias, RMSE and correlation, we evaluate the performance of the reanalyses with respect to (a) the local surface characteristics (offshore, flat onshore, hilly onshore), (b) various height levels (60 to 200 m) and (c) the diurnal cycle. As expected, we find that the reanalyses show the smallest errors to observations at offshore sites. Over land, MERRA-2 generally overestimates wind speeds, while COSMO-REA6 and ERA5 represent the average wind speed more realistically. At sites with flat terrain, ERA5 correlates better with observations than COSMO-REA6. In contrast, COSMO-REA6 performs slightly better over hilly terrain, which can be explained by the higher horizontal resolution. In terms of diurnal variation, ERA5 outperforms both other reanalyses. While the overestimation of MERRA-2 is consistent throughout the day, COSMO-REA6 significantly underestimates wind speed at night over flat and hilly terrain due to a misrepresentation of nightly low level jets and mountain and valley breezes. Regarding the representation of downtime of wind turbines due to low/high wind speeds, we find that MERRA-2 is consistently underperforming with respect to the other reanalyses. Here COSMO-REA6 performs better over the ocean, while ERA5 shows the best results over land.

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Wind Energy Potential in Nine Coastal Sites in Malaysia

مجلة جامعة فلسطين التقنية للأبحاث ◽

10.53671/pturj.v1i1.7 ◽

2013 ◽

Vol 1 (1) ◽

pp. 10-15

Author(s):

Kamaruzzaman Sopian ◽

Tamer Khatib

Keyword(s):

Wind Speed ◽

Wind Energy ◽

Data Bank ◽

Energy Potential ◽

Average Wind Speed ◽

Speed Distribution ◽

Average Wind ◽

Wind Speed Distribution ◽

Wind Energy Potential ◽

Swept Area

In this paper, the wind energy potential in Malaysia is examined by analyzing hourly wind speed data for nine coastal sites namely Bintulu, Kota Kinabalu, Kuala Terengganu, Kuching, Kudat, Mersing, Sandakan, Tawau and Pulau Langkawi. The monthly averages of wind speed and wind energy are calculated. Moreover, the wind speed distribution histogram is constructed for these sites. The results showed that the average wind speed for these sites is in the range of (1.8-2.9) m/s while the annual energy of the wind hitting a wind turbine with a 1 m2 swept area is in the range of (15.4-25.2) kWh/m2.annum. This paper provides a data bank for wind energy for Malaysia.

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A methodology for the design and testing of atmospheric boundary layer models for wind energy applications

Wind Energy Science ◽

10.5194/wes-2-35-2017 ◽

2017 ◽

Vol 2 (1) ◽

pp. 35-54 ◽

Cited By ~ 11

Author(s):

Javier Sanz Rodrigo ◽

Matthew Churchfield ◽

Branko Kosovic

Keyword(s):

Boundary Layer ◽

Wind Speed ◽

Wind Energy ◽

Atmospheric Boundary Layer ◽

Wind Direction ◽

Added Value ◽

Mean Flow ◽

Energy Applications ◽

Single Column ◽

Design And Testing

Abstract. The GEWEX Atmospheric Boundary Layer Studies (GABLS) 1, 2 and 3 are used to develop a methodology for the design and testing of Reynolds-averaged Navier–Stokes (RANS) atmospheric boundary layer (ABL) models for wind energy applications. The first two GABLS cases are based on idealized boundary conditions and are suitable for verification purposes by comparing with results from higher-fidelity models based on large-eddy simulation. Results from three single-column RANS models, of 1st, 1.5th and 2nd turbulence closure order, show high consistency in predicting the mean flow. The third GABLS case is suitable for the study of these ABL models under realistic forcing such that validation versus observations from the Cabauw meteorological tower are possible. The case consists on a diurnal cycle that leads to a nocturnal low-level jet and addresses fundamental questions related to the definition of the large-scale forcing, the interaction of the ABL with the surface and the evaluation of model results with observations. The simulations are evaluated in terms of surface-layer fluxes and wind energy quantities of interest: rotor equivalent wind speed, hub-height wind direction, wind speed shear and wind direction veer. The characterization of mesoscale forcing is based on spatially and temporally averaged momentum budget terms from Weather Research and Forecasting (WRF) simulations. These mesoscale tendencies are used to drive single-column models, which were verified previously in the first two GABLS cases, to first demonstrate that they can produce similar wind profile characteristics to the WRF simulations even though the physics are more simplified. The added value of incorporating different forcing mechanisms into microscale models is quantified by systematically removing forcing terms in the momentum and heat equations. This mesoscale-to-microscale modeling approach is affected, to a large extent, by the input uncertainties of the mesoscale tendencies. Deviations from the profile observations are reduced by introducing observational nudging based on measurements that are typically available from wind energy campaigns. This allows the discussion of the added value of using remote sensing instruments versus tower measurements in the assessment of wind profiles for tall wind turbines reaching heights of 200 m.

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