What is wind shear?

Wind shear refers to the change in wind direction with altitude. It is an integral consideration when calculating the output of wind power systems, as wind speeds and wind shear can significantly impact turbine performance.

Does shear affect wind speed?

Even before turbines extended beyond 100 m above the surface, some researchers pointed out the effects of shear on the shape of wind speed profiles and therefore turbine power production. Because of shear and veer, hub-height wind speeds alone may not be representative of the flow over the entire rotor disk.

Does wind shear reduce energy production?

Analysis of data from a US Great Plains wind plant suggests that wind shear defined by a power law coefficient α greater than 0.2 reduces annual energy production (AEP) by approximately 1.1–1.2%, depending on wind speed (Rareshide et al. (2009).

What is the speed shear range of a wind turbine?

Most observations within this speed shear range took place between 6.5 and 8 m s −1 (Fig. 12), corresponding to the most affected turbine performance–speed regimes. On the other hand, highly stratified atmospheric conditions, characterized by large speed shear (), evidenced statistically distinct power differences for larger wind speeds (Fig. 15b).

Does speed and direction shear separate over- and underperformance at a wind farm?

Segregating normalized turbine power into speed shear (α) and direction shear (β) combinations revealed a threshold (referred to as α∕β threshold from now on) that separates over- and underperformance at this wind farm (Fig. 14). Speed and direction shear combinations that satisfy Eq.

Does turbine efficiency depend on the shear situation?

Only by using the equivalent wind speed it is possible to see if the turbine efficiency actually depends on the shear situation, i.e. if the turbine extracts less power in some shear situations than in others whereas the energy available in the wind is the same.