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

Barber, Sarah; Schubiger, Alain; Koller, Sara; Eggli, Dominik; Radi, Alexander; Rumpf, Andreas; Knaus, Hermann

doi:10.5194/wes-2021-158

Cited by 2 publications

(9 citation statements)

References 22 publications

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“…The fourth study involves recent work by the current authors, which compared the accuracy of simulations using seven different WRA workflows at five different complex sites in terms of wind speed and AEP [19]. The wind speed accuracy was assessed by averaging the absolute difference between simulated and measured wind speeds for each 12 simulated wind direction sectors.…”

Section: Evaluation Of Wind Energy Toolsmentioning

confidence: 99%

“…In this section, the decision process is tested on one site and demonstrated on four further sites based on simulations from a range of WRA workflows as described in detail in [19]. After the tests on the first site, the weightings of the "skill score before" parameters were adjusted to optimise the results, and then applied to the other four sites.…”

Section: Decision Process Test and Demonstrationmentioning

confidence: 99%

“…Site 5 is a planned site that cannot be described in detail here for confidentiality reasons. More details about the sites can be found in [19].…”

Section: Sites and Workflowsmentioning

confidence: 99%

“…Seven different WRA workflows based on the wind modelling tools WindPro (labelled "WF-1"), WindSim ("WF-2"), ANSYS CFX ("WF-3"), ANSYS Fluent (RANS: "WF-4"; SBES: "WF-5"), PALM ("WF-6") and E-Wind ("WF-7") were applied, as described below: Further details can be found in [19].…”

Section: Sites and Workflowsmentioning

confidence: 99%

“…Detailed simulation results can be found in [19]. The resulting skill vs. costs plots for all sites are shown in Figure 5.…”

Section: Test Of Decision Process At Site 1 321 Skill Vs Costs Plotsmentioning

confidence: 99%

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A New Decision Process for Choosing the Wind Resource Assessment Workflow with the Best Compromise between Accuracy and Costs for a Given Project in Complex Terrain

et al. 2022

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In wind energy, the accuracy of the estimation of the wind resource has an enormous effect on the expected rate of return of a project. For a given project, the wind resource assessor is faced with a difficult choice of a wide range of simulation tools and workflows with varying accuracies (or “skill”) and costs. There is currently no guideline or process available in the industry for helping with the decision of the most “optimal” choice—and this is particularly challenging in mountainous (or “complex”) terrain. In this work, a new decision process for selecting the Wind Resource Assessment (WRA) workflow that would expect to deliver the best compromise between skill and costs for a given wind energy project is developed, with a focus on complex terrain. This involves estimating the expected skill and cost scores using a set of pre-defined weighted parameters. The new process is designed and tested by applying seven different WRA workflows to five different complex terrain sites. The quality of the decision process is then assessed for all the sites by comparing the decision made (i.e., choice of optimal workflow) using the expected skill and cost scores with the decision made using the actual skill and cost scores (obtained by comparing measurements and simulations at a validation location). The results show that the decision process works well, but the accuracy decreases as the site complexity increases. It is therefore concluded that some of the parameter weightings should be dependent on site complexity. On-going work involves collecting more data from a large range of sites, implementing measures to reduce the subjectivity of the process and developing a reliable and robust automated decision tool for the industry.

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Section: Evaluation Of Wind Energy Toolsmentioning

confidence: 99%

Section: Decision Process Test and Demonstrationmentioning

confidence: 99%

“…Site 5 is a planned site that cannot be described in detail here for confidentiality reasons. More details about the sites can be found in [19].…”

Section: Sites and Workflowsmentioning

confidence: 99%

Section: Sites and Workflowsmentioning

confidence: 99%

“…Detailed simulation results can be found in [19]. The resulting skill vs. costs plots for all sites are shown in Figure 5.…”

Section: Test Of Decision Process At Site 1 321 Skill Vs Costs Plotsmentioning

confidence: 99%

See 3 more Smart Citations

A New Decision Process for Choosing the Wind Resource Assessment Workflow with the Best Compromise between Accuracy and Costs for a Given Project in Complex Terrain

et al. 2022

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Computational fluid dynamics studies on wind turbine interactions with the turbulent local flow field influenced by complex topography and thermal stratification

2022

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Abstract. This paper shows the results of computational fluid dynamics (CFD) studies of turbulent flow fields and their effects on a wind turbine in complex terrain. As part of the WINSENT project, a research test site comprising four meteorological masts and two research wind turbines is currently being constructed in the Swabian Alps in southern Germany. This work is an essential part of the research of the southern German wind energy research cluster WindForS. The test site in complex terrain is characterised by a densely forested escarpment and a flat plateau downstream of the slope. The met masts and wind turbines are built on this plateau. In the first part, high-resolution delayed detached eddy simulations are performed to separately investigate the effects of the forested escarpment and of thermal stratification on the flow field and accordingly on the wind turbine. In the second part, both these effects are included for a real observed case in March 2021. There, unstable conditions prevailed and the forest showed low leaf area densities due to the winter conditions. It is shown that atmospheric turbulence, forests, orographies, and thermal stratification must be considered when assessing the impact on wind turbines in complex terrain. All of these effects influence the flow field both at the turbine position and in its wake. The wind speed at the test site is accelerated by up to 60 %, which could affect the annual energy production significantly. But otherwise turbulent structures of the forest wake cross the rotor plane temporarily and thereby affect the turbine inflow. Moreover, convective conditions and upward flows caused by the orography have an impact on the turbine's power output as inclined flows result in asymmetric torque distributions. The wind turbine wake and the forest wake mix further downstream, resulting in a faster decay of the turbine wake than in neutral conditions or without forest. The paper also describes how the turbulent flow in the wake changes in the presence of thermal stratification, which is evident in order to be able to numerically represent the flow-physical changes in the diurnal cycle well.

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

Cited by 2 publications

References 22 publications

A New Decision Process for Choosing the Wind Resource Assessment Workflow with the Best Compromise between Accuracy and Costs for a Given Project in Complex Terrain

A New Decision Process for Choosing the Wind Resource Assessment Workflow with the Best Compromise between Accuracy and Costs for a Given Project in Complex Terrain

Computational fluid dynamics studies on wind turbine interactions with the turbulent local flow field influenced by complex topography and thermal stratification

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