Wind power density loss for wind turbines due to upstream hills

摘要

The installation of wind turbines in hilly terrain is not straightforward. For the planning, an accurate and reliable estimation of the annual energy production has to be performed. The local wind potential is a crucial quantity within this assessment, however, it is unknown in most cases. In order to obtain more reliable data about wind potential in hilly terrain, an investigation in an atmospheric boundary layer tunnel is presented, delivering detailed information on the interaction of upstream hills and wind power potential for wind turbines. The investigations were performed for the case, when wind turbine height and hill height are at least in the same order of magnitude. Specific exposure coefficients are given depending on the distance of the upstream hill, the surface roughness of the terrain and the ratio of turbine height to hill height.