Turbulent Air Reduces Wind Energy

The amount of Energy produced by the wind turbines of a wind farm depends not only on wind speed, but also on the stability of atmospheric conditions

Two US researchers, Sonia Wharton from the Lawrence Livermore National Laboratory (California) and Julie Lundquist from the University of Colorado, have found that, with equal wind speed, stable atmospheric conditions enhance energy production. On the contrary, when the conditions are unstable, the average wind power output falls by 15%.

The atmosphere becomes unsteady when the vertical shifts of hot and cold air are significant. In turn, this situation has to do with the temperature variations between altitudes and the ground. Indeed, unstable climate conditions favour turbulences and wind shears, which reduce wind turbine production.

The research, published in January 2012 on the journal Environmental Research Letters, was conducted over one year in a large-scale wind farm in California, and is based on a wider range of data compared with previous studies. It considered heights up to 200 metres, thus providing useful information on the stability of the atmosphere.

The findings of the study show that climate conditions need more in-depth studies, and that plant management should focus with greater attention on the assessment of atmospheric instability. Thus will allow a more accurate forecast of electricity production at a specific time, with the possibility of improving estimates of distribution network loads.