A new method for the pragmatic choice of wind models for Wind Resource Assessment in complex terrain

Barber, Sarah; Schubiger, Alain; Wagenbrenner, N. S.; Fatras, Nicolas; Nordborg, Henrik

doi:10.5194/wes-2019-95

Cited by 4 publications

(13 citation statements)

References 7 publications

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“…Detailed simulation results for each site can be found in the final project report (Barber et al, 2001). This includes speedup factors and turning between calibration and validation locations, comparisons of simulated and measured wind speed and direction profiles for all wind directions and wind speed contours.…”

Section: Simulation Results -Wind Speedsmentioning

confidence: 99%

“…However, the effect of the weighted averaging is not insignificant. This was found to be because the largest deviations from the measurements occurred at the more frequent wind speeds, and is discussed further in Barber et al (2001). In this section, the results at the validation location for each site are shown in terms of AEP, which was calculated site from the simulation results for each workflow as described in Section 2.…”

Section: Sitementioning

confidence: 96%

“…Details of the variations of the AEP for each wind direction sector can be found in Barber et al (2001). It was found that the large over-prediction in AEP by the WF-3 and WF-4 workflows mainly occurs because of the over-prediction in the 240°sector, because this is the most frequently occurring sector.…”

Section: Sitementioning

confidence: 99%

“…A very small difference was observed. Details of the variations of the AEP for each wind direction sector can be found in Barber et al (2001). It was found that a large variation between model and sector exists, without a particular trend.…”

Section: Sitementioning

confidence: 99%

“…Details of the variations of the AEP for each wind direction sector can be found in Barber et al (2001). It was found that the AEP was under-predicted in the three most frequent sectors (120°, 270°and 300°), leading to an overall under-prediction of AEP.…”

Section: Sitementioning

confidence: 99%

See 4 more Smart Citations

The wide range of factors contributing to Wind Resource Assessment accuracy in complex terrain

Barber¹,

Schubiger²,

Koller

et al. 2022

Preprint

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Abstract. Understanding the uncertainties of Wind Resource Assessments (WRA) is key to reducing project risks, and this is particularly challenging in mountainous terrain. In the academic literature, many complex flow sites have been investigated, but they all focus on comparing wind speeds from selected wind directions, and do not focus on the overall AEP. In this work, a range of simulations are carried out with seven different wind modelling tools at five different complex terrain sites and the results compared to wind speed measurements at validation locations. This is then extended to AEP estimations (without wake effects), showing that wind profile prediction accuracy does not translate directly or linearly to AEP accuracy. This is firstly because there is a surprisingly large variation in energy production calculation techniques between tools, and secondly because the AEP depends strongly upon the relative strength and occurrence of the wind speed in the most commonly-occurring wind direction sectors. This means that the wind model that produces the most accurate wind predictions for a certain wind direction over a certain time period does not always result in the most suitable model for the AEP estimation of a given complex terrain site. In fact, the large number of steps within the WRA process often lead to the choice of wind model being less important for the overall WRA accuracy than would suggest by only looking at wind speeds. It is therefore concluded that it is vitally important for researchers to consider overall AEP – and all the steps towards calculating it – when evaluating simulation accuracies of flow over complex terrain.

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Section: Simulation Results -Wind Speedsmentioning

confidence: 99%

Section: Sitementioning

confidence: 96%

Section: Sitementioning

confidence: 99%

Section: Sitementioning

confidence: 99%

Section: Sitementioning

confidence: 99%

See 3 more Smart Citations

The wide range of factors contributing to Wind Resource Assessment accuracy in complex terrain

Barber¹,

Schubiger²,

Koller

et al. 2022

Preprint

Self Cite

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Actual Total Cost reduction of commercial CFD modelling tools for Wind Resource Assessment in complex terrain

Barber

Schubiger

Koller

et al. 2020

J. Phys.: Conf. Ser.

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In this paper, new automated processes for applying the commercial Computational Fluid Dynamics (CFD) tools ANSYS Fluent and ANSYS CFX to wind modelling in complex terrain are developed with the goal of decreasing the Actual Total Costs (ATC) related to planning wind energy projects. Simulations are carried out at the complex terrain site Stotten in southern Germany using ANSYS Fluent and ANSYS CFX, and the ATCs related to the simulations estimated. The simulation set-up and post-processing effort are identified as having the highest effect on the ATC, and therefore the automated processes focus on reducing the effort of these tasks. Simulations of the same test site are carried out with the new automated processes, and compared to the manual processes as well as to an industry-standard tool, WindSim. The new automated tools are found to reduce the ATC of this case by a factor of 12 for Fluent and seven for CFX, to approximately half the value of WindSim. All three simulations show similar deviations compared to measurements and therefore these results are comparable. It should be noted that these results are highly specific to this case, and the absolute cost-saving values cannot be directly transferred to other cases. Nevertheless, it can be concluded that these new processes have significantly reduced the Actual Total Cost and are likely to have a large effect on the choice of the most cost-effective model for a given wind energy project. On-going work involves quantifying the effect of these cost savings on the choice of most appropriate model for this simulation site and further comparing the results to measurements.

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Comparison Metrics Microscale Simulation Challenge for Wind Resource Assessment

Hammer

Barber

Remmler³

et al. 2023

Preprint

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Abstract. The main goals of a wind resource assessment (WRA) at a given site are to estimate the wind speed and annual energy production (AEP) of the planned wind turbines. Several steps are involved in going from initial wind speed estimations of specific locations to a comprehensive full-scale AEP assessment. These steps differ significantly between the chosen tool and the individuals performing the examination. The goal of this work is to compare different WRA simulation tools at the Perdigão site in Portugal, for which a large amount of wind measurement data is available, in terms of both accuracy and costs. Results from nine different simulations from five different modellers were obtained via the "IEA Wind Task 31 Comparison metrics simulation challenge for wind resource assessment in complex terrain", consisting of a range of linear models, Reynolds-Averaged Navier-Stokes (RANS) computational fluid dynamics models and Large Eddy Simulations (LES). The wind speed and AEP prediction errors for three different met mast positions across the site were investigated and further translated into relative “skill” and “cost” scores, using a method previously developed by the authors. This allowed the most optimal simulation tool in terms of accuracy and cost to be chosen for this site. It was found that the RANS simulations achieved very high prediction accuracy at relatively low costs for both wind speed and AEP estimations. The LES simulations achieved great wind speed prediction for certain conditions, but at a much higher cost, which in turn also reduced the number of possible simulations, leading to a decrease in AEP prediction accuracy. For some of the simulations, the forest canopy was explicitly modelled, which was proven to be beneficial for wind speed predictions at lower heights above the ground, but lead to under-estimations of wind speeds at upper heights, decreasing the AEP prediction accuracy. Lastly, low correlation qualities between wind speed and AEP prediction error were found for each position, showing that accurate wind modelling is not necessarily the only important variable in the WRA process, and that all the steps must be considered.

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A new method for the pragmatic choice of wind models for Wind Resource Assessment in complex terrain

Cited by 4 publications

References 7 publications

The wide range of factors contributing to Wind Resource Assessment accuracy in complex terrain

The wide range of factors contributing to Wind Resource Assessment accuracy in complex terrain

Actual Total Cost reduction of commercial CFD modelling tools for Wind Resource Assessment in complex terrain

Comparison Metrics Microscale Simulation Challenge for Wind Resource Assessment

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