In the article, a modeling block diagram was developed in the Matlab/Simulink environment for a horizontal-axis wind energy system with a rated power of 20.5 kW. This model makes it possible to analyze the energy performance of the turbine under variable wind flows and different blade pitch angles. According to the research results, when the wind speed varies within the range of 3–12 m/s and the blade installation angles are between 0° and 10°, the rotor rotational speed is 7–25 rad/s, the turbine mechanical torque is 45.71–821 Nm, and the turbine mechanical power is 0.32–20.6 kW. It has been substantiated that when the wind turbine blades are installed at a pitch angle of 0°, the optimal tip-speed ratio is equal to 8.1.