In this historical phase of action against climate change, an important role is played by renewable energy sources such as wind energy sources. This thesis describes the implementation of the Blade Element Momentum (BEM) method in a MATLAB code which allows the evaluation of the aerodynamic performances for a given horizontal-axis wind turbine (HAWT). Moreover, the Matlab code integrates the aerodynamic performance calculations with Computer-Aided Design (CAD) to accelerate the preliminary design process. The geometrical characteristics of the wind turbine are inputs for the MATLAB code, which in turn automatically produces an output CAD file for the CATIA environment. Once the CAD file has been created, the MATLAB code provides the airfoil polars by either using the software XFoil or importing the polar data available in the literature; the aerodynamic coefficients of the airfoils are then used in the BEM algorithm.