Evaluation of a Wind Power Parameterization Using Tower Observations

The spatial and temporal components of a published wind power parameterization method are evaluated using observed winds (9 m to 90 m) from 7 years of data collected at 4 towers in the Kennedy Space Center/Cape Canaveral Air Force Station network. The temporal component is governed by two parameterization inputs which represent the amplitude and mean of an assumed sinusoidal diurnal variation of the ratio of the 80 m-to-10 m winds respectively. Comparison with tower observations show that the estimates of the mean ratio are robust but biased high -indicating that the temporal variation of the observations can be approximated by, but is not, a pure sinusoid. The observed and parameterized amplitude are poorly correlated as the amplitude estimate is sensitive to small phase shifts in the diurnal variation of the ratio of the wind speeds. The observed annual wind power, for the site, is consistent with what is known about the wind energy potential in Florida while wind power estimates based on the temporal extrapolation are more than twice that observed. The erroneous wind power estimate is shown to be related to an assumption that negative amplitude estimates are indicative of a diurnal phase shift in the ratio of the 80 m-to-10 m winds. When the assumed phase shift is removed from the data and the observed inputs are applied, the parameterized 80 m wind power estimates were comparable to those observed. The spatial component of the parameterization depends on a least squares fit of four different wind extrapolation methods to 00 and 12 UTC wind profiles. Comparison of the observed 80 m winds with those obtained via the least squares method indicates that the 00 UTC 80 m wind and power estimates, exceed (by as much as 1 m/s, 200 W/m2 respectively) the observed 80 m winds and power for all months. When compared against the 00 UTC regression, the 12 UTC 80 m wind and power estimates are closer to the observed power for all months. The power law often yields