PNNL

Abstract

As wind energy deployment grows, interactions between wind plants and the surrounding environment become more prevalent. The current investigation seeks to understand these interactions by characterizing the impact of wind plants on the planetary boundary layer height (PBLH), utilizing observations from the American WAKE ExperimeNt (AWAKEN) campaign. Given the ambiguity of the PBLH under stable atmospheric conditions, a comparison of different methods for identifying PBLH is first conducted. Then, using one of those methods that is thermodynamic-based and another that is turbulence-based, the distributions of PBLH measured at spatially distributed sites are compared under a range of atmospheric conditions. Both methods show a clear increase in PBLH downstream of a wind plant for stable conditions. These impacts are strongest when the upstream PBLH is shallow, with the thermodynamic method showing a PBLH increase of 33-39\% and the turbulence-based method showing a 141\% increase. At 20~km downstream of the wind plant, these effects are no longer observed. The results of this investigation show that wind plants can modify the surrounding atmosphere, but that these impacts are confined to the immediate vicinity of the plant.