The impact of baroclinicity on wind farm performance and wind farm wakes

The performance of wind farms strongly depends on the interaction with the atmospheric boundary layer (ABL). In simulations of wind farms, the ABL is typically assumed barotropic, i.e. the pressure gradient forcing the wind is vertically uniform. In practice, the ABL often tends to be baroclinic; the pressure gradient changes with altitude. This alters the atmospheric turbulence and wind resources above the wind farm, and affects the wind farm-atmosphere interactions [1,2]. We used large-eddy simulations to evaluate the wind farm performance and wake recovery in four baroclinic scenarios and compared them to a barotropic reference case.



We found that changes in atmospheric turbulence alter the recovery of the first turbine wakes, such that the power production of the initial rows can increase by up to 20% or decrease by up to 11%. Furthermore, differences in velocity resources aloft alter the turbulent entrainment of kinetic energy downstream in the wind farm, yielding differences in power ranging from -5% to +10%. Additionally, baroclinicity affects the wind farm wake recovery rate, as it is also governed by turbulent entrainment.



These results demonstrate that baroclinicity should be incorporated in wind farm design tools.



[1] Momen, J. Atmos. Sci. 75, 3797–3821 (2018).

[2] Stieren et al., PRX Energy. 1, 023007 (2022).