Accounting for Tree Growth in Resource Assessment: A Case Study using the VENTOS Code on Kyle Wind Farm
A study was carried out to determine the wind fow map around the proposed 200 MW Kyle wind farm site in Scotland. A comparison was made between the wind flow map in 2005 and in 2017, according to a proposed forestry management plan. Estimated tree heights in 2005 and 2017, for each parcel of forest, were determined based on plantation date, species and rate of growth. The VENTOS CFD code was used, including a specially implemented canopy model. Results showed increased wind speed in 2017, and a reduction in turbulence intensity of several percent. For the 2005 case, the model yielded a speedup ratio between the two 50 m site masts, within 2% of measured, for those directions where this comparison was possible. This gives some con
dence when applying the model to the future case. Canopy characteristics immediately around a turbine have a critical impact on production, pointing up the importance of collecting accurate forestry data. This study highlighted the dynamic nature of forestry and showed that a solution based on the state as-is before site construction is unlikely to be representative over the lifetime of the wind park. This is particularly true of managed forest plantations, where this study indicated that careful forest management can improve site performance, while avoiding wholesale clearing of large areas of forest.
