Abstract. In the present study, combination of the standalone dynamic wake meandering (DWM) model with Reynolds-averaged Navier-Stokes (RANS) CFD solutions for ambient ABL flows is introduced, and its predictive performance for annual energy production (AEP) is evaluated against Vestas' SCADA data for six operating wind farms over semi-complex terrains under neutral conditions. The performances of conventional linear and quadratic wake superposition techniques are also compared, together with the in-house implemention of successive hierarchical merging approaches. As compared to our standard procedure based on the Jensen model in WindPRO, the overall results are promising, leading to a significant improvement in AEP accuracy for four of the six sites. While the conventional linear superposition shows the best performance for the improved four sites, the hierarchical square superposition shows the least deteriorated result for the other two sites.
IntroductionAs investments on large-scale wind farms grow, precise estimation of annual energy production (AEP) is becoming increasingly important, especially during the planning phase of a project, in order to guarantee business case certainty. The challenge of AEP evaluation mainly originates from its multi-disciplinary nature, where prediction uncertainties from various elementary sources such as ambient ABLs, wakes, power curves and risk mitigation strategies are all blended together. Preliminary uncertainty analyses suggest that no single uncertainty source plays a dominant role but rather the most limiting factor varies case by case [1]. Therefore, integration of most advanced models for all individual elementary physics would be a key step towards improved AEP accuracy.Vestas has devoted substantial efforts to ensure most up-to-date CFD capabilities, including highfidelity simulation techniques as well as steady/unsteady Reynolds-averaged Navier-Stokes (RANS) models. In our standard micro-siting approach, AEP is estimated by combining a wind resource file (RSF) from RANS simulation with the Jensen model within the software WindPRO. The objective of the present study is to introduce the dynamic wake meandering (DWM) model to our process in order to account for wake physics of higher complexity at an affordable cost, and validate its predictive performance for AEP against Vestas' SCADA data for various operating wind farms.