An Application of the Weather Prediction Model and the Wind Statistics in Wind Farm Development

Offshore wind energy have played an important role in sustainable energy recently. In the development of the offshore wind farm, two regional wind resources assessments (WRA): 1.wind statistics on the measurements of meteorological mast and 2.application of numerical weather prediction (NWP) to wind simulation are significant and indispensable without doubts. On the other hand, in order to generate more electrical power, the size of the wind turbine has been enlarged for extracting more momentum from the atmosphere. However, it also implies that the influences of the atmospheric boundary layer and the environment will be significantly occurred. Thus, issues such as the environmental impacts on the atmosphere due to the wind farm operation are worthy to be alerted. According to the above statements, in this study, the simulation by conducting atmospheric research software (WRF model) with the comparison of data provided by the Fu-Hai met mast is drawn to present the offshore wind energy of Changhua, Taiwan. Further, the wind farm development taken in combination with the engineering perspectives are also addressed. Considering the wind farm operation, parameterization of the wind turbine proposed by Fitch et al. was applied to simulate the 30 SWT-4.0-120 wind turbines (Phase I + II) designed by the Fuhai Wind Farm Corporation at offshore Changhua. Results of the parameterization showed a distinct wake with a nearly 2 (m/s) velocity deficit behind the scheduled wind farm. To verify them, a 1D momentum theory is used for fundamental validation and the further evaluation of the wake effect such as the wake characteristics, wake fluctuation and related properties are followed. Moreover, a modified wake model based on Jensen’s approaches is proposed to preliminarily evaluate the wake effect of wind farm. Having compared with the results of the modified wake model and Fitch scheme, it was found that the wake decay constant of wind farm had a substantially connection to the suggestion of single wind turbine. It is, therefore indirect to indicate the wake performance of wind farm can be imitated to a single wind turbine. In addition to numerical simulation, the objective assessment of wind resources at offshore Changhua is concerned. Based on the regular criterion proposed by the IEC standards, the wind statistics on the measurements of one month winter (Oct. 7~Nov. 7, 2015) and summer (May, 2016) data are presented to evaluate the seasonal wind potential. Finally, the typical extreme weather condition of Taiwan are illustrated by the wind data of Du- Juan Typhoon (Sep. 27~29, 2015). Additionally, to verify the maximum allowable wind condition of the scheduled wind turbine, the results were compared with the extreme wind speed model (EWM) suggested by IEC standards. To conclude, in Taiwan, this is a first study which might be of importance in applying the NWP model to wind farm development, attempting to explain the wake effect of wind farm with engineering perspectives, as well as in providing the wind statistics with a comprehensive understanding of the offshore wind resources of Changhua.