Forecasting Wind Speed Using the Proposed Wavelet Neural Network

Abstract

Wind energy is one of the speedy processing technologies in the energy generation industry and the most economical methods of electrical power generation. For the reliability of system, it is wanted to improve highly appropriate wind speed forecasting methods. The wavelet transform is a powerful mathematical technique that converts an analyzed signal into a time-frequency representation. This technique has proven useful in a nonstationary time series forecasting. The aims of this study are to propose a wavelet function by derivation of a quotient from two different Lucas polynomials, as well as a comparison between an artificial neural network (ANN) and wavelet-artificial neural network (WNN). We used the proposed wavelet, Mexican hat, Morlet, Gaussian, Haar, Daubechies, and Coiflet to transform the wind speed data using the continuous wavelet transform (CWT). MATLAB software was used to implement the CWT and ANN. The proposed models were applied in the meteorological field to forecast the daily wind speed data that were collected from the meteorological directorate of Sulaymaniyah which is a city located in the Kurdistan region of Iraq for the period (Jan. 2011–Dec. 2020). Five different performance criteria during calibration and validation, the root mean square error ( $\mathrm{R}\mathrm{M}\mathrm{S}\mathrm{E}$ ), mean square error ( $\mathrm{M}\mathrm{S}\mathrm{E}$ ), mean absolute percentage error $\mathrm{M}\mathrm{A}\mathrm{P}\mathrm{E}$ , mean absolute error $\mathrm{M}\mathrm{A}\mathrm{E}$ , and coefficient of determination ( $R^2$ ), were evaluated. When studying, analyzing, and comparing these models, the results of the study concluded that the proposed wavelet-ANN is the best result ( $\mathrm{M}\mathrm{S}\mathrm{E}=0.00072$ , $\mathrm{R}\mathrm{M}\mathrm{S}\mathrm{E}=0.02683$ , $\mathrm{M}\mathrm{A}\mathrm{P}\mathrm{E}=2.32400$ , and $\left.R^2=0.99983\right)$ .