Wind power generation prediction in a complex site by comparing different numerical tools

Abstract

This paper focuses on the estimation of annual energy production (AEP) by simulating the flowfield on a complex terrain located in the northeast region of Brazil using different numerical approaches: CFD RANS with k-ε and k-ω turbulence models (WindSim), simple mass-conserving (WindMap), and refined mesoscale (SiteWind). The last two are run through OpenWind software. Wind observations from five meteorological masts are used to adjust the models. Optimal layouts for a hypothetical wind farm with 50 wind turbines are obtained over each of the four wind fields to predict the power generation. As non-negligible differences are found on the spatial distribution of the winds simulated by the different models, the layouts are also substantially different. The AEP is calculated to compare scenarios varying the layouts over the wind fields. The distinct micrositing generate differences of up to 13 % on AEP prediction, which could mean the impact of an improper siting on the wind farm profitability. It is not plausible to categorically claim the superiority of accuracy of one model over the others. Nonetheless, the observed data provide an indicative that the refined mesoscale model was able to better capture the wind acceleration in the western region of the studied site.