Further Evidence on Modeling Wind Speed and Time-Varying Turbulence

In a recent study of the simultaneous modeling of mean wind speed and its volatility, [Ewing, Kruse, and Thompson (2008), Analysis of time-varying turbulence in geographically-dispersed wind energy markets, Energy Sources, Part B: Economics, Planning, and Policy, 3:340-347] employ an ARMA-GARCH-M model to find that (1) current wind speed is dependent on immediate past wind speed; (2) regardless of location wind speed exhibits time-varying turbulence; and (3) the degree to which turbulence and wind speed are statistically correlated varies by location. This study extends the ARMA-GARCH-M model by examining the ARMA-Component GARCH-M model to differentiate between the permanent and transitory components of the conditional volatility (turbulence) associated with wind speed. The results indicate that shocks to wind speed (i.e., wind gusts) have varying effects on the transitory and permanent components of wind turbulence. At measurement heights of 20 and 40 meters, the shocks primarily affect the permanent component whereas the transitory component is larger than the permanent component at measurement heights of 70, 77, and 78 meters.